Ellis Surgical Approaches to the Facial Skeleton PDF

Contents Section I General Principles for Approaches to the Facial Skeleton 1 1 General Principles for Approaches to the Facial Skeleton 3 Section II Periorbita Approaches 7 2 Lower Eyelid Approach 9 3 Transconjunctival Approach 38 4 Supraorbital Eyebrow Approach 51 5 Upper Eyelid Approach 55 Section III Coronal Approach 63 6 Coronal Approach 65 Section IV Transoral Approachs to the Facial Skeleton 95 7 Maxillary Vestibular Approach 97 8 Mandibular Vestibular Approach 109 Section V Transfacial Approaches to the Mandible 121 9 Submandibular Approach 123 10 Retromandibular Approach 139 11 Rhytidectomy Approach 154 Section VI Approaches to the Temporomandibular Joint 161 12 Preauricular Approach 163 Section VII Surgical Approaches to the Nasal Skeleton 187 13 External (Open) Approach 189 14 Endonasal Approach 204 Index 217 xiii SECTION I GENERAL PRINCIPLES FOR APPROACHES TO THE FACIAL SKELETON 1 General Principles For Approaches To The Facial Skeleton aximum success in skeletal surgery depends on adequate access to and exposure of the M skeleton. Skeletal surgery is simplified and expedited when the involved parts are sufficiently exposed. In orthopedic surgery, especially of the appendicular skeleton, a basic rule is to select the most direct approach possible to the underlying bone. Thus, incisions are usually placed very near the area of interest while major nerves and blood vessels are retracted. This involves little regard for aesthetics, allowing the orthopedics surgeon greater leeway in the location, direction, and length of the incision. Surgery of the facial skeleton, however, differs from general orthopedics surgery in several important ways. First, the primary factor in incision placement is not surgical convenience but facial esthetics. The face is plainly visible to everyone, and a conspicuous scar may create a cosmetic deformity that can be as troubling to the individual as the reason for which the surgery was performed. Cosmetic considerations are critical in light of the emphasis that Western society places on facial appearance. Thus, as we will see in this text, all of the incisions used on the face must be placed in inconspicuous areas, sometimes very distant from the underlying osseous skeleton on which the surgery is being performed. For instance, placement of incisions in the oral cavity allows superb exposure of much of the facial skeleton with a completely hidden scar. A second factor that differentiates incision placement on the face from that anywhere else on the body is the presence of the muscles and nerve (cranial nerve VII) of facial expression. The muscles are subcutaneous structures, and the facial nerve branches that supply them can be traumatized if incisions are placed in their path. This can result in a “paralyzed” face, which is not only a severe cosmetic deformity but can have great functional ramifications as well. For instance, if the ability to close the eye is lost, corneal damage can ensue, affecting sight. Thus, placement of incisions and dissections that expose the facial skeleton must ensure that damage to the facial nerve is unlikely. Many dissections to expose the skeleton require care and electrical nerve stimulation to identify and protect the nerve. Approaches using incisions in the facial skin must take into consideration the muscles of facial expression. This is especially important for approaches to the orbit, where the orbicularis oculi muscle must be traversed. Closure of some incisions also affects the muscle of facial expression. For instance, if a maxillary vestibular incision is closed without proper reorientation of the perinasal muscle, widening of the nasal base will occur. A third factor in facial incision placement is the presence of many important sensory nerves exiting the skull at multiple locations. The facial soft tissues have more sensory input per unit area than soft tissues anywhere else in the body. Loss of this sensory input can be a great inconvenience to the individual. Thus, the incision and approaches used must attempt to spare the sensory nerves from injury. An example is dissection of the supraorbital nerve from its foramen/notch in the coronal approach. 3 Other important factors are the age of the patient, existing unique anatomy, and patient expectations. The age of the patient is important because of the possible presence of the wrinkles that come with age. Skin wrinkles serve as a guide and offer the surgeon the opportunity to place incisions within or parallel to them. Existing anatomic features unique to the individual cal also facilitate or hamper incision placement. For instance, pre-existent lacerations can be used by themselves or extended to provide surgical exposure of the underlying skeleton. The position, direction, and depth of a laceration are important variables in determining its utility. The presence of old scars may direct incision placement; the old scar may be excised and used to approach the skeleton. On other occasions, an old scar may not lend itself to use and may even cause the new incision to be placed at a position that will avoid it. Hair distribution may also direct the position of incisions. For instance, the incision for the coronal approach is largely determined by the position of the hairline. Ethnic characteristics also have a bearing on whether or not an incision will be placed in a conspicuous area. History or ethnic propensity for hypertrophic scarring, keloid formation, and hyper- or hypopigmentation may alter the decision as to whether or where to place an incision. The pacient’s expectations and wishes must always be considered in any decision made about incision location. For instance, patients who repeatedly require treatment for facial injuries may not be concerned with local cutaneous approaches to the naso-orbito-ethmoid region, whereas other individuals may be very concerned. Therefore the choice of surgical approach depends at least partly on the patient. PRINCIPLES OF INCISION PLACEMENT Incision placed in areas that are not readily visible, such as within the oral cavity or far behind the hairline, are not of esthetic concern. Incisions placed on exposed surfaces of the face, however, must follow some basic principles so that the scar will be less conspicuous. These principles are outlined in the following text. Avoid Important Neurovascular Structures Although this is an obvious consideration, placement of incisions to avoid anatomic hazards is a secondary consideration in the face. Instead, placing the incision in a cosmetically acceptable location takes priority. Important neurovascular structures encountered during the dissection must deal with by dissecting around them or retracting them. Use as Long an Incision as Necessary Many surgeons have a tendency to use short incisions. If the soft tissues around a short incision must be stretched to obtain sufficient exposure of the skeleton, the additional retraction trauma may create a less satisfactory scar than a longer incision. A well-placed long incision may be less perceptible than a short incision that is placed poorly or requires great retraction. A long incision heals as quickly as a short one. Place Incision Perpendicular to the Surface of Nonhair-bearing Skin Except in some very specific regions, an incision perpendicular to the skin surface permits the wound margins to be reapproximated in an accurate, layer-to-layer fashion. Incisions performed obliquely to the surface of the skin are susceptible to marginal necrosis and overlapping of the edges during closure. Incisions in hair-bearing tissue, however, should parallel the direction of the hair so that fewer follicles are transected. An oblique incision requires a more meticulous closure because of the tendency of the margins to overlap during suturing. Subcutaneous may have to be placed more deeply to avoid necrosis of an oblique edge overlap 4 Place Incisions in the Line of Minimal Tension The lines of minimal tension, also called relaxed skin tension lines, are result of the skin’s adaptation to function and are also related to the elastic nature of the underlying dermis (Fig. 1-1). The intermittent and chronic contraction of the muscles of facial expression create depressed Figure 1- 1 - lines of minimal tension (released skin tension lines ) are very conspicuous in the aged face. These lines of creases are good choices for incision placement because the scars resulting from the incision are imperceptible. 5 creases in the skin of the face. These creases become more visible and depressed as one ages. For instance, the supraorbital wrinkle lines and the transverse lines of the forehead are caused by the contraction of the frontalis muscles, which insert into the skin of the lower forehead. In the upper eyelids, many fine perpendicular strands of fibers of the elevator aponeurosis terminate in the dermis of the skin an along the tarsus to form the supratarsal fold. Similar insertions in the lower lid create fine horizontal lines, which are accentuates by the circumferential contraction of the orbicularis oculi muscle. Incision lines should be made within the lines of minimal tension. Incision made in or parallel to such a line or crease will become inconspicuous if careful closure is performed. Any incision or portion of an incision that crosses such a crease, however, is often very conspicuous. Seek for Other Favorable Sites for Incision Placement If incision cannot be placed in the lines of minimal tension, they can be made inconspicuous by placement inside an orifice such as the mouth, nose, or eyelid; within hair-bearing areas or location that can be covered by hair; or at the junction of two anatomic landmarks such as the esthetic units of the face. 6 SECTION II PERIORBITAL APPROACHES A standard series of incisions has been used extensively to approach the inferior and lateral orbital rims. Properly placed incisions offer excellent access with minimal morbidity and scarring. The most commonly used approaches are those made on the external surface of the lower eyelid, the conjunctival side of the lower eyelid, the skin of the lateral brow, and the skin of the lower eyelid. This section describes these four approaches. Other periorbital approaches exists and can be useful. Existing lacerations of 2 cm or larger can also be used to approach the orbit. 2 Lower Eyelid Approach Approaches through the external side of the lower eyelid offer superb exposure to the inferior orbital rim, the floor of the orbit, the lateral orbit, and the inferior portion of the medial orbital rim and wall. These approaches are given many names in the literature, based primarily on the position of the skin incision in the lower eyelid (e.g., blepharoplasty, subciliary, lower lid, subtarsal, infraorbital). Because of the natural skin creases in the lower eyelid and the thinness of eyelid skin, scars become inconspicuous with time. The laxity of skin here also makes the eyelid virtually immune to keloid formation. The infraorbital incision, however, is almost noticeable to some degree. SURGICAL ANATOMY Lower Eyelid (1) In the sagittal section, the lower eyelid consists of at least four distinct layers – the skin and subcutaneous tissue, the orbicularis oculi muscle, the tarsus (upper 4 to 5 mm) or orbital septum, and the conjunctiva (Fig. 2-1). Skin. The outermost layer is the skin, comprising the epidermis and the very thin dermis. The skin of the eyelids is the thinnest skin in the body, and has many elastic fibers that allow it to be stretched during dissection and retraction. It is loosely attached to the underlying muscle; hence, in contrast to the situation in most areas of the face, relatively large quantities of fluid may accumulate subcutaneously in this loose connective tissue. The skin derives its blood supply from the underlying perforating muscle vessel (see subsequent text). Muscle. Subjacent and adherent to the skin lies the orbicularis oculi muscle, the sphincter of the eyelids (Fig. 2-2). This muscle completely encircles the palpebral fissure and extends over the skeleton of the orbit. In can thus be divided into orbital and palpebral portions (Fig. 2-3). The palpebral portion can be further subdivided into the pretarsal portion (the muscle superficial to the tarsal plates) and the preseptal portion (the muscle superficial to the orbital septum). The palpebral portions of the orbicularis oculi muscle are very thin ion cross section, especially at the junction of the pretarsal and preseptal portion. The orbital portion of the orbicularis oculi muscle takes its origin medially from the bones of the medial orbital rim and the medial canthal tendon. The peripheral fibers sweep across the eyelid over the orbital margin in a series of concentric loops, the more central ones forming almost complete rings. In the lower eyelid, the orbital portion extends below the inferior orbital rim onto the cheek, and covers the origins of the elevator muscle of the upper lip and nasal ala. The orbital portion of the orbicuralis oculi muscle is responsible for the tight closure of the eye. The preseptal portion of the orbicularis oculi muscle originates from the medial canthal tendon and lacrimal diaphragm and passes across the lid as a series of half-ellipses, meeting at the lateral canthal tendon. The upper and lower pretarsal muscles contribute to a common lateral canthal tendon about 7 mm from the lateral orbital tubercle, where it inserts. Medially, they unite to form the medial canthal tendon, which inserts on the medial orbital margin, the anterior crest, and nasal bones. The palpebral portions of the orbicularis oculi muscle function to close the eye without effort, as in blinking. It also functions to maintain contact between the lower lid and the ocular globe. 9 Figure 2- 1 Sagital section through orbit and globe. C=palpebral conjuntiva; IO=inferior oblique muscle; IR=inferior rectus muscle; OO=orbicularis oculi muscle; OS=orbital septum;P=periosteum/periorbita; TP=tarsal plate. 10 Figure 2- 2 Anatomic dissection of orbicularis oculi muscle fibers. Note the extreme thinness in this older specimen Figure 2- 3 Orbital and palpebral portions of orbicularis oculi muscle. The palpebral portion is divided into the fibers in front of the tarsus (pretarsal portion) and those in front of the orbital septum (preseptal portion). 11 The orbicularis oculi muscle receives innervation from the lateral side, from branches of the facial nerve that enter the muscle on its deep surface. The blood supply to the orbicularis oculi muscle is from the external facial artery tributaries that come from deep branches of the ophthalmic artery. These arterial branches form a marginal arcade, traversing between the tarsal plate and muscle and giving rise to branches perforating the substance of the muscle, orbital septum, and tarsal plate. Orbital Septum/Tarsus. The orbital septum is a fascial structure that forms a diaphragm between the contents of the orbit and the superficial face (Figs. 2-1 and 2-4). It is usually more dense laterally than medially, but varies considerably in thickness from one individual to another. The orbital septum is a fascial extension of the periosteum of the bones of the face and orbit. It takes its origin along the orbital rim for most of its extent. Laterally and inferolaterally, however, it arises from the periosteum 1 to 2 mm beyond the rim of the orbit. Thus, it is necessary to dissect a few mm lateral and/or inferior to the orbital rim before incising the periosteum to prevent incising through the orbital septum. The orbital septum in the lower eyelid inserts onto the inferior margin of the lower tarsus. The tarsal plate of the lower eyelid is a somewhat thin, pliable fibrocartilaginous structure that gives form and support to the lower eyelid (Figs. 2-5 and 2-6). The edge of the tarsus adjacent to the free border of the lid parallels the palpebral fissure, while the deeper (inferior) border is curved so that the tarsus is somewhat semilunar in shape. It is also, of course, curved to conform to the outer Figure 2- 4 Anatomic dissection of orbital septum in the lower eyelid. Note the thinness in this older specimen. 12 Figure 2- 5 Anterior surface of tarsal plates and canthal tendons (left eye). Note the difference in size between the upper and lower tarsal plates. surface of the eyeball. The inferior tarsus is considerably smaller than the superior one, the greatest height of the inferior being about 4 to 5 mm and that of the superior about 10 mm. The tarsal glands sandwiched between the layer of fibrocartilage in the lower eyelid are smaller than their upper eyelid counterpart, and exit on the lid margin near the lash follicles. The lashes are supported by their roots, attached to fibrous tissue on the tarsal plate, not in the orbicularis oculi muscle anterior to the tarsal plate. Laterally, the tarsal plate becomes a fibrous band that adjoins the structural counterpart from the upper lid, forming the lateral canthal tendon. Medially, the tarsal plate also becomes fibrous and shelters the inferior lacrimal canaliculus behind as it becomes the medial canthal tendon. Embedded within the tarsal plates are large sebaceous glands called the tarsal or Meibomian glands, whose ducts may be seen along the lid margin. A grayish line or a slight groove sometimes visible between the lashes and the openings of the tarsal glands represents the junction of the two fundamental portions of the eyelid, the skin and muscle on one hand and the tarsus (the plate of closely packed tarsal glands) and conjunctiva on the other. This indicates a plane along which the lid may be split into anterior and posterior portion with minimal scarring. Figure 2- 6 Posterior surface of the tarsal plates and canthal tendons (left eye). Note the vertically arranged Meibomian glands, visible through the thin 13 Palpebral Conjunctiva. The conjunctiva that lines the inner surface of the eyelids is called the palpebral conjunctiva (see Fig. 2-1). It adheres firmly to the tarsal plate, and as it extends inferiorly toward the inferior conjunctival fornix, it becomes more loosely bound. At the inferior conjunctival fornix, the conjunctiva sweeps onto the ocular globe to become the bulbar conjunctiva. Lateral Canthal Tendon The lateral canthal tendon, ligament, or raphé as it is frequently called, is a fibrous extension of the tarsal plates laterally toward the orbital rim (fig. 2-7). As will be seen in the medial canthal tendon, the lateral tendon has a superficial and deep component. The base of the ligamentous complex is shaped like a Y and is attached to the external angle of the two tarsi (Fig. 2-8). The two divisions diverge from the tarsi and the superficial component extends laterally just under, or intermingling with the orbicularis oculi muscle. It continues lateral to the orbital rim and inserts into the periosteum overlying the lateral orbital rim and the temporalis fascia just lateral to the orbital rim. The thicker, stronger deep component of the lateral canthal tendon courses posterolaterally, inserting into the periosteum of the orbital tubercle of the zygoma, approximately 2 to 3 mm posterior to the orbital rim. The space between the two bundles of the lateral canthal tendon is filled with loose connective tissue. Figure 2- 7 Anatomic dissection of the deep portion of the lateral canthal tendon. Note that it attaches posterior to the orbital rim. 14 Figure 2- 8 Medial and lateral canthal tendon complexes. Note that the anterior limb of the medial canthal tendon (AL, MCT) and the posterior limb of the lateral canthal tendon (PL LCT) are thicker. The thicker anterior portion of the medial canthal tendon attaches to the anterior lacrimal crest of the maxilla and the frontal process of the maxilla. The thinner posterior limb of the medial canthal tendon (PL MCT) attaches along the posterior lacrimal crest of the lacrimal bone. The thick posterior portion of the lateral canthal tendon (PL LCT) attaches to the orbital (Whitnall’s) tubercle of the zygoma, 3 to 4 mm posterior to the lateral orbital rim. The thinner anterior fibers course laterally to mingle with the orbicularis oculi muscle fibers and the periosteum of the lateral orbital rim. 15 Medial Canthal Tendon The medial canthal tendon attaches to the medial bony orbit by superficial and deep components that attach to the anterior and posterior lacrimal crests (Fig 2-8 and 2-9) (2,3). The medial canthal tendon originates at the nasal border of the upper and lower tarsi, where the preseptal muscle divide into superficial and deeps heads (4). The lacrimal puncta are located here. Thus, the lacrimal canaliculi of the upper and lower lid margins extend from the medial border of the tarsi toward and behind the medial canthus. Continuing medially, the tendon fans out to insert into the anterior lacrimal crest and beyond onto the frontal process of the maxilla. The anterior lacrimal crest, which is 2 to 3 mm medial to the canthal apex, protects the lacrimal sac. Thus, an incision farther medial than 3 mm from the canthus misses both the canaliculi and the sac. The anterior horizontal segment is the strongest component of the medial canthal tendon complex and is attached most firmly at the anterior lacrimal crest. The thinner posterior limb inserts on the posterior lacrimal crest and functions to maintain the eyelids in a posture tangent to the globe. The resultant vectors of all of the canthal attachments suggests that resuspension of the entire complex following disruption should be posterior and superior to the anterior lacrimal crest. Figure 2-9 Anatomic specimen showing the anterior and posterior components of the medial canthal tendon complex. AL MCT=anterior limb; ALC=anterior lacrimal crest; LS=lacrimal sac; PL MCT=posterior lomb; PLC=posterior lacrimal crest. 16 Infraorbital Groove The infraorbital neurovascular bundle enters the posterior orbit through the inferior orbital fissure and runs almost straight anteriorly in the infraorbital groove of the orbital floor (Fig. 2-10). More anteriorly, the infraorbital groove is usually roofed over with a thin layer of bone, forming the infraorbital canal, which leads the neurovascular bundle through the infraorbital foramen to the superficial structures of the face. Figure 2 10 Anatomic dissection of the orbital floor, lateral and inferior orbital rims. IOF=Inferior orbital fissure anfter incision of contents; ION-Infraorbital nerve in canal/groove after unroofing; ZFN=zygomaticofacial nerve; ZTN=zygomaticotemporal nerve. 17 TECHNIQUE Several external incisions of the lower eyelid to gain access to the infraorbital rim and orbital floor have been described. The major difference between them is the level at which the incision is placed in the skin of the eyelid and the level at which the muscle is thansected to expose the orbital septum/periosteum. Each incision has advantages and disadvantages. The approach shown here, however, is a standard approach that encompasses all of the techniques used in the others. It is most commonly called subciliary incision, but is also known as infraciliary or blefharoplasty incision. This incision is merely a lower lid incision at a higher level that in the lower lid incision, made just below the eyelashes. The main advantage of this incision is the imperceptible scar that it creates. Further, it can be extended laterally for additional exposure of the entire lateral orbital rim. Once the skin is incised, the surgeon has three options. The first is to dissect between the skin and the muscle until the orbital rim is reached, at which point another incision through muscle and periosteum is made to the bone. The second option is to incise through muscle at the same level as the skin incision and dissect down just anterior to the orbital septum to the orbital rim. The third option is a combination of these in which subcutaneous dissection toward the rim proceeds for a few millimeters followed by incision through the muscle at a lower level, producing a step-incision, then following the orbital septum to the rim. Although all three options are advocated by several surgeons, each has advantages and disadvantages. The first option, in which a subcutaneous dissection to the level of the infraorbital rim is made, leaves an extremely thin skin flap. This flap is technically difficult to elevate, and accidental "buttonhole" dehiscence can occur. A further problem that may occasionally be seen is a slight darkening of the skin in this area after healing. Presumably, the skin flap becomes avascular and essentially acts as a skin graft. An increase in the incidence of ectropion has also been noted by some investigators with this approach. Entropion and lash problems have occasionally been experienced after this "skin only" flap. The second option, in which the dissection is made between muscle and orbital septum, is technically less difficult. Care must be taken, however, because the thin orbital septum can be easily violated, causing periorbital fat to herniate into the wound. In practice, this is more a nuisance than a problem. The skin and muscle flap, however, presumably maintains a better blood supply to the skin, and pigmentation of the lower lid has not been seen. The third technique, in which a layered dissection is used, avoids the disadvantages of the others. The main advantage of the "stepped" incision through skin and muscle is that the pretarsal fibers of the orbicularis oculi can be kept attached to the tarsal plate, presumably assisting in maintaninig the position of the eyelid and its contact with the globe postoperatively. 18 Step 1. Protection of the Globe Protection of the cornea during operative procedures around the orbit may reduce ocular injuries. If one is operating on the skin side of the eyelids to approach the orbital rim and/or orbital floor, a temporary tarsorrhaphy or scleral shell may be useful. These are simply removed at the completion of the operation (Figs. 2-11 and 2-12). Figure 2-11 Placement of tarsorrhaphy suture. 19 Figure 2-12 tarsorrhaphy suture placed. The suture is left long to be used as a traction suture for dissection. 20 Step 2. Identification of and Marking Incision Line One should carefully evaluate the skin creases around the orbit. If the tissues are edematous, the skin surrounding the opposite orbit can be used to obtain an appreciation for the direction of creases. If one chooses to use a crease at the midlevel of the lower eyelid, he should note carefully the direction of the skin crease. Commonly, the crease tails off inferiorly as it extends laterally (Fig. 2-13). If access to the orbital floor and inferior orbital rim are all that is necessary, this "lower lid" incision is satisfactory and will result in an imperceptible scar. This incision, however, should not change direction from the original skin crease or a noticeable scar will result. The tendency is to curve the incision superiorly as it extends laterally. This should be avoided, with the incision placed in the middle of the lower lid unless a natural skin crease does the same. Figure 2-13 Subciliary incision being made. The incision is approximately 2 mm below the eyelashes and can be extended laterally as necessary (top dashed line). It is made throug skin only. If one chooses to use a natural skin crease located more inferiorly for incision (lower dashed line), the incision must follow the crease as it tails off inferiorly. One should not use the lower incision and then extend the incision more superiorly as the lateral orbital rim is approached or the relaxed skin tension lines will be crossed, 21 Step 3. Vasoconstriction The incision line is marked before infiltration of a vasoconstrictor. One must remember that the tissues will distort after infiltration and a perceptible crease may disappear following the injection. Dilute epinephrine solutions before incision are useful for hemostasis and to separate the tissue planes intentionally before incision. This later use, i.e., to "balloon out" the tissue, facilitates incision in the thin lids. Step 4. Skin Incision The incision for a subciliary approach is made approximately 2 mm inferior to the lashes, along the entire length of the lid (Fig. 2-13). The incision may be extended laterally approximately 1 to 1,5 cm in a natural crease if more exposure is necessary (see subsequent text). If no natural skin crease extends laterally from the lateral palpebral fissure, the extension can usually be made straight laterally or slightly inferolaterally. The depth of the inicial incision is through the skin only. One should see the underlying muscle when the skin in incised completely (Fig. 2-13). Figure 2-14 Subcutaneous dissection of skin, leaving pretarsal portion of orbicularis muscle attached to the tarsus. Dissection 4 to 6 mm inferiorly in this plane is adequate. 22 Step 5. Subcutaneous Dissection Subcutaneous dissection toward the inferior orbital rim proceeds for a few millimeters using sharp dissection with a scalpel or scissors (Fig. 2-14 and 2-15). The tarsorrhaphy suture is used to retract the lower lid superiorly to assist in the dissection. The skin should be separated from the pretarsal portion of the orbicularis oculi muscle along the entire extent of the incision. Approximately 4 to 6 mm of subcutaneous dissection is ample. Figure 2-15 Sagital plane through the orbit and globe demonstrating the subcutaneous dissection of the lid margin. 23 Step 6. Sub-Orbicularis Dissection Scissors with slightly blunted tips are used to dissect through the orbicularis oculi muscle (by spreading in the direction of the muscle) to the periosteum overlying the lateral orbital rim (Fig. 2- 16). The muscle is dissected initially over the bony rim because the depth is much easier to determine here than over the orbital septum. Supraperiosteal dissection continues in this submuscular plane inferiorly along the lateral rim, over the anterior edge of the infraorbital rim, and finally, the scissors are used to spread upward in this pocket into the lower eyelid (Figs. 2-17 and 2- 18). The supraperiosteal dissection places the instrument in the proper plane for dissection into the lower eyelid, i.e., between the orbicularis oculi muscle and the orbital septum. The convexity of the curved scissors is outward. Figure 2-16 Use of scissors to dissect through orbicularis oculi muscle over lateral orbital rim to identify periosteum. 24 Figure 2-17 Dissection between orbicularis oculi muscle and orbital septum. The dissection should extend completely along the orbital rim and superiorly to the level of subcutaneous dissection. 25 Figure 2-18 Sagital plane through orbit showing level and extent of dissection. Note the bridge of orbicularis oculi muscle remaining between the lid and skin/muscle flap. 26 Step 7. Incision Between Pretarsal and Preseptal Portions of Orbicularis Oculi Muscle An attachment of orbicularis oculi muscle will remain, extending from the tarsal plane to the skin muscle flap, which was just elevated from the orbital septum (Fig.2-19). This muscle is now incised with scissors inferior to the level of the initial skin incision (Fig. 2-20). Figure 2-19 Incision through the bridge of orbicularis oculi muscle. 27 Figure 2-20 Sagital plane through orbit showing incision of the bridge of orbicularis oculi muscle. 28 Step 8. Periosteal Incision Once the skin/muscle flap of tissue is elevated from the lower eyelid, it can be retracted inferiorly, extending below the inferior orbital rim. If no violation of the orbital septum occurred, one should see the tarsal plate above with the pretarsal portion of orbicularis oculi still attached, and the orbital septum below extending to the infraorbital rim. An incision through the periosteum on the anterior surface of the maxilla and zygoma, 2 to 3 mm below or lateral the orbital rim, can be made with a scalpel (Fig. 2-21). The incision through the periosteum at this level avoids the insertion of the orbital septum along the orbital margin. The infraorbital nerve is approximately 5 to 7 mm inferior to the orbital rim and should be avoided when the periosteal incision is made. Figure 2-21 Incision through periosteum along anterior maxilla, 3 to 4 mm inferior to infraorbital rim. Note the pretarsal muscle still remaining on the inferior tarsus and the orbital septum, which restricts the orbital fat from entering the field. 29 Step 9. Subperiosteal Dissection of Anterior Maxilla and/or Orbit The sharp end of a periosteal elevator is pulled across the full length of the periosteal incision to separate the incised edges. Periosteal elevators are then used to strip the periosteum from the underlying osseous skeleton, both along the anterior surface of the maxilla and zygoma and inside the orbit. The inferior orbital rim is superior to the orbital floor just behind it. After the periosteum of the infraorbital rim is elevated, the elevator is positioned vertically, stripping inferiorly as it proceeds posteriorly for the first centimeter or so (Figs. 2-22 and 2-23). The bony origin of the inferior oblique muscle, the only muscle in the orbit that does not arise from its apex, will be stripped during the subperiosteal dissection. The muscle arises from the floor of the medial orbit Figure 2-22 Subperiosteal dissection of anterior maxilla and orbital floor. Note that the periosteal elevator entering the orbit is placed almost vertically as dissection proceeds behind the rim. In the anterior region, the floor of the orbit is at a lower level than the crest of the rim, necessitating dissection inferiorly just behind the crest of the rim. 30 Figure 2-23 Sagital plane through orbit showing subperiosteal dissection of the anterior maxilla and orbital floor. 31 just posterior to the orbital rim and lateral to the upper aperture of the nasolacrimal canal, and may also arise partly from the lacrimal fascia over the lacrimal sac (Fig. 2-24). During dissection, one will readily encounter the inferior orbital fissure. The periosteum of the orbit (periorbita) sweeps downward into the fissure. If necessary, the contents of the inferior orbital fissure can be incised to provide more exposure (Figs. 2-25 and 2-26). Figure 2-24 Anatomic dissection showing the position of the inferior oblique muscle (*). It should not be directly visualized if one stays in the subperiosteal plane because its origin will be stripped from the orbital floor along with the periosteum. 32 Figure 2-25 Anatomic dissection showing incision through the contents of the inferior orbital fissure to facilitate orbital dissection. These tissues should first be cauterized with bipolar electrocoagulation to prevent bleeding when incised. Figure 2-26 Anatomic dissection showing increased exposure of orbit after incision of contents of inferior orbital fissure. 33 Step 10. Closure Closure is usually performed in two layers - the periosteum and skin (Fig.2-27). Suturing of the orbicularis oculi muscle is difficult and of little value. Interrupted or running ressorbable periosteal sutures, such as 5-0 catgut, ensure that the soft tissue stripped from the anterior surface of the maxilla and zygoma are repositioned. A 6-0 nonresorbable or fast-resorbing suture is then run along the skin margin. If a lateral extension was made, one should place one or two deep resorbable sutures in the incised orbicularis oculi muscle overlying the lateral orbital rim. Figure 2 27 Closure of periosteum with interrupted resorbable sutures. 34 Step 11. Suspensory Suture for Lower Eyelid One problem that may accompany any incision to gain access to the infraorbital rim and orbital floor is a vertical shortening of the lower lid after healing. This probably occurs as a result of scarring and shortening of the orbital septum. To reduce the incidence of this problem, superior support of the lower lid for several days (or until gross edema has resolved) after surgery is beneficial. The most direct method involves the use of a suture placed through the skin surface of the lower lid just inferior to the gray line that is taped to the forehead (Fig. 2-28). This lifts and supports the lower eyelids in a lengthened position, and helps dissipate lid edema. One may examine the globe and vision simply by removing the tape from the forehead and opening the eyelids. To maintain gentle upward support to the lower eyelid, it is important that the suture be taped to prevent if from slipping. To accomplish this, a three-tape technique has proven effective. The first layer of tape is attached to the skin as a base. The suture is then drawn over the first layer and a second layer of tape applied, with the suture held to the base layer of tape. The suture, however, can still slip between the two layers of tape. To prevent this, the suture is drawn inferiorly over the face of the second layer of tape, and a third layer of tape is then placed over the second. Figure 2-28 Lower eyelid suspensory suture placed at completion of surgery. The suture is placed just below the lower eyelashes (just above the subciliary incision), taking care to engage the tarsal plate. it is taped to the forehead in the manner shown to provide firm suspension. 35 ALTERNATIVE TECHNIQUE: EXTENDED LOWER EYELID APPROACH The extended lower eyelid approach provides access to the entire lateral orbital rim to a point approximately 10 to 12 mm superior to the frontozygomatic suture. For this added exposure, however, amore generous incision and wide undermining are necessary. Additionally, the lateral canthal tendon must be stripped from its insertions and carefully repositioned. In spite of these concerns, the approach is useful when one requires access to the entire lateral orbit, lateral orbital rim, orbital floor, and inferior orbital rim. The incision for the "extended" subciliary approach is exactly as described for the standard subciliary incision, but the incision must be extended laterally approximately 1 to 1,5 cm in a natural crease (see Fig. 2-13). If no natural skin crease extends laterally from the lateral palpebral fissure, the extension can usually be made straight laterally, or slightly inferolaterally. Supraperiosteal dissection of the entire lateral orbital rim is performed with scissor dissection to a point above the frontozygomatic suture (Fig. 2-29). The orbicularis oculi musculature and superficial portion of the lateral canthal tendon are retracted as the dissection proceeds. Figure 2-29 Technique used to obtain increased exposure of the lateral orbital rim. The initial incision is extended laterally 1 to 1,5 cm, and supraperiosteal dissection along the lateral orbital rim proceeds 36 With retraction, an incision through the periosteum 2 to 3 mm lateral to the lateral orbital rim is made from the highest point obtained with supraperiosteal dissection (Fig. 2-30). The periosteal incision is connected to the one described from the standard approach to the orbital floor and infraorbital rim (see previous text). Subperiosteal dissection must strip all of the tissue from the orbital floor and lateral orbital wall. This includes stripping the insertions of the deep portion of the lateral canthal tendon, Lockwood's suspensory ligament, and the lateral check ligament, from the orbital (Whitnall's) tubercle of the zygoma. Generous subperiosteal dissection deep into the lateral orbit allows retraction of these tissues to expose the frontozygomatic suture. Figure 2 30 Dissection to the level of the frontozygomatic suture. The tissues superficial to the periosteum are retracted superiorly with a small retractor and an incision through periosteum is made 3 to 4 mm lateral to the lateral orbital rim. Subperiosteal dissection exposes the entire lateral orbital rim. Dissection into the lateral orbit frees the tissues and allows retraction superiorly. No lateral canthopexy is necessary if careful repositioning and suturing of periosteum along the lateral orbital rim are performed. This maneuver brings the superficial portion of the lateral canthal tendon into proper position, giving the lateral palpebral fissure satisfactory appearance. REFERENCES 1. Zide BM, Jelks Gw : Surgical Anatomy of the Orbit. New York, Raven Press, 1985 2. Anderson RC: The medial canthal tendon branches out, Arch Ophthalmol 95:2051, 1977 3. Zide BM, McCarthy JG : The medial canthus revised. An anatomical basis for canthopexy, Ann Plast Surg 11:1, 1983 4. Rodriguez RL, Zide BM : Reconstruction of the medial canthus. Clin Plast Surg 15:255, 1988. 37 3 Transconjunctival Approach T he transconjuntival incision, also called the inferior fornix incision, is a popular approach for exposure of the orbital floor and infraorbital rim. Two basic transconjuntival approaches, the preseptal and retroseptal, have been described. These approaches vary in the relationship of the orbital septum to the path of dissection (Fig. 3-1). The retroseptal approach is more direct than the preseptal approach and easier to perform. The periorbital fat may be encountered during the retroseptal approach, but this is of little concern and causes no ill effects. A lateral canthotomy is frequently used with transconjunctival incisions for improved lateral exposure. The approach that will be demonstrated here is the retroseptal transconjunctival approach with a lateral canthotomy. The main advantage of tranconjunctival approaches is that they produce excellent cosmetic results because the scar is hidden in the conjunctiva. If a canthotomy is performed in conjunction with the approach, the only visible scar is the lateral extension, which heals with an inconspicuous scar. Another advantage is that these techniques are rapid, and no skin or muscle dissection is necessary. One disadvantage of the transconjunctival approach is that the medial extent of the incision is limited by the lacrimal drainage system. If access to the medial third of the orbital rim is needed, cutaneous approaches through the lower eyelid should be considered because they allow extension of the incision as far medially as necessary. Figure 3 1 Sagital section through orbit showing preseptal and retroseptal placement of incision. 38 SURGICAL ANATOMY Lower Eyelid In addition to an understanding of the anatomy described in Chapter 2 for the lower eyelid approach, the transconjunctival approach requires understanding of a few additional matters. Lower Lid Retractors. During full downward gaze, the lower lid descends approximately 2 mm in conjunction with movement of the globe itself. The inferior rectus muscle, which rotates the globe downward, simultaneously uses its fascial extension to retract the lower eyelid. This extension, which arises from the inferior rectus, contains sympathetic-innervated muscle fibers and is commonly called the capsulopalpebral fascia (Fig. 3-2). This fascia is incised during the transconjunctival approach to the orbit, but seems to be inconsequential from a clinical standpoint. Figure 3 2 Sagital section through orbit and globe. C=palpebral conjunctiva; IO=inferior oblique muscle; IR=inferior rectus muscle; LLR=lower lid retractors; OO=orbicularis oculi muscle; OS=orbital septum; P=periosteum/periorbita; TP=tarsal plate. 39 TECHNIQUE Step 1. Protection of the Globe Protection of the cornea during operative procedures around the orbit is beneficial. Because tarsorrhphy is precluded with this approach, a corneal shield may be placed to protect the globe (Fig. 3-3). Figure 3 3 Placement of a corneal protector (shield). Two or three traction sutures placed through the lower lid assist in the placement of the shield and in subsequent surgery. 40 Step 2. Vasoconstriction A vasoconstrictor can be injected under the conjunctiva to aid in hemostasis. A minimal amount is necessary. Additional solution is infiltrated in the area of the lateral canthotomy. Step 3. Traction Sutures in Lower Eyelid The lower eyelid is everted with fine forceps and two or three traction sutures are placed through the eyelid (see Fig. 3-3). These should be placed stright through the eyelid, from palpebral conjunctiva to skin, approximately 4 to 5 mm below the lid margin to ensure that the tarsal plate is included in the suture. Step 4. Lateral Canthotomy and Inferior Cantholysis If a lateral canthotomy is used, the approach begins with it. One tip of pointed scissors is placed inside the palpebral fissure, extending laterally to the depth of the underlying lateral orbital rim (approximately 7 to 10 mm). The scissors are used to cut horizontally through the lateral palpebral fissure (Fig. 3-4). The structure cut in the horizontal plane are skin, orbicularis muscle, orbital septum, lateral canthal tendon, and conjunctiva. Figure 3 4 Initial incision for lateral canthotomy. 41 The traction sutures are used to evert the lower lid. Note that the lower lid is still tethered to the lateral orbital rim by the inferior limb of the lateral canthal tendon (Fig. 3-5). This is isolated by retraction and incised with scissors. To perform the contholysis, the scissors will need to be positioned with a vertical orientation (Fig. 3-6). Once the cantholysis is complete, an immediate release of the lower lid from the lateral orbital rim is noted (Fig. 3-7). The surgeon will be able to evert the lower lid more effectivelly. Figure 3 5 Anatomic dissection shoing result after initial canthopexy illustrated in Figure 3-3. Note that the inferior limb of the lateral canthal tendon (*) is still attached to the lower tarsus, preventing mobilization. 42 Figure 3 6 Technique of inferior cantholysis. Figure 3 7 Anatomic dissection shoing rsult after cantholysis illustrated in Figure 3-5. Note that the inferior limb of the lateral canthal tendon (*) has been severed, allowing the lower lid great mobility. 43 Step 5. Transconjunctival Incision Once the lower lid is everted, note the position of the lower tarsal plate through the conjunctiva. Blunt-tipped pointed scissors are used to dissect through the small incision through the conjunctiva made during the lateral canthotomy, inferiorly toward the infraorbital rim. The traction sutures are used to evert the lower eyelid during the dissection. Spread the scissors to clear a pocket just posterior to the orbital septum, ending just posterior to the orbital rim (Fig. 3-8). Figure 3 8 Scissors placed into the initial canthopexy incision to dissect in the subconjunctival plane. The dissection should be just below the tarsal plate and extend no farther medially than the lacrimal punctum. Note how the traction sutures through the lower lid assist in this dissection. 44 Scissors are used to icise the conjunctiva and lower lid retractors midway between the inferior margin of the tarsal plate and the inferior conjunctival fornix (Figs. 3-9 and 3-10). The incision should not extend farther medially than the lacrimal punctum. A traction suture through the cut edge of the bulbar conjunctiva can be placed to assist in retraction and to hold the corneal shield in place (Fig. 3-11). Figure 3 9 Incision of the conjunctiva below the tarsal plate. 45 Figure 3 10 Sagital plane through the orbit and globe demonstrating level and plane of incision. The conjunctiva and lower lid retractors are incised with scissors. 46 Step 6. Periosteal Incision With retraction of the orbital contents and the lower lid, using suitable retractors, a scalpel is used to icise the periorbita, taking care to stay lateral to the lacrimal sac (Fig. 3-11). The incision through the periorbita is just posterior to the orbital rim when the retroseptal approach is used. Figure 3 11 Incision through periosteum. To facilitate this maneuver, a traction suture is placed through the cut end of the conjunctiva to retract the tissue and maintain the position of the corneal shield. Small retractors are placed so that the lower lid is retracted to the level of the anterior surface of the infraorbital rim. A broad retractor is placed just posterior to the infraorbital rim, confinig the orbital fat. The intervening tissue along the infraorbital rim is the periosteum. The incision is made through the periosteum just posterior to the infraorbital rim. 47 Step 7. Subperiosteal Orbital Dissection Periosteal elevators are used to strip the periosteum over the orbital rim and anterior surface of the maxilla and zygoma, and orbital floor (Fig. 3-12). A broad malleable retractor should be placed as soon as feasible to protect the orbit and to confine any herniating periorbital fat. Figure 3 12 Subperiosteal dissection of the orbital floor. Note the traction suture placed through the cut end of the conjunctiva, which assists in retracting the conjunctiva and maintains the corneal shield in place. 48 Step 8. Closure Periosteal sutures are not absolutely necessary, but if exposure permits, the can be placed, The conjunctiva is closed with a running 6-0 chromic gut suture. The ends of the suture may be buried. No attempt is made to reapproximate the lower lid retractors because they are intimately in contact with the conjunctiva and will be adequately repositioned with closure of that layer. Once the conjunctiva is closed, an inferior canthopexy is performed (Fig. 3-13). Figure 3 13 Closure of transconjunctival incision and inferior canthopexy. A running 6-0 gut suture is initially placed through the conjunctiva (and lower lid retractors). The inferior canthopexy suture is placed next, followed by skin sutures along the dermal canthotomy incision. 49 A 4-0 polyglactin or other long lasting suture is used to reattach the lateral portion of the inferior tarsal plate to the superior portion of the canthal tendon and surrounding tissues. It is important that this suture be securely placed in the appropriate location or the lateral canthal area will never appear normal. When the inferior limb of the canthal tendon is severed during the approach, only a minute amount of canthal tendon remains attached to the lower tarsus. Therefore the canthopexy suture can be placed through the lateral border of the tarsus if the tendon attached is insufficient to hold a suture. It is easier to pass the suture through the lateral border of the lower tarsus and/or cut portion of the lateral canthal tendon if the skin is dissected slightly from them. This is very easily performed by taking a #15 scalpel and incising between the tarsus and the skin. A cleavage plane exists in this location, and the tissue readily separates. The tarsus is grasped with forceps and a suture is passed through either the cut tendon or the lateral border of the tarsus in such a fashion that a firm bit of tissue is engaged. Once a goode bite of lower tarsus has been taken with the suture, the suture needle should be placed through the superior limb of the lateral canthal tendon. The bulk of the lateral canthal tendon attaches to the orbital tubercle, 3 to 4 mm posterior to the orbital margin. Following canthotomy, the superior limb of the canthal tendon is still attached to the orbital tubercle. It is important to place the suture as deep behind the orbital rim as possible to adapt the lower eyelid to the globe. If the suture is not properly placed, the eyelid will not contact the globe laterally, giving an unnatural appearance. Therefore, the suture needle should pass very far posteriorly and superiorly to ensure that it grasps the superior limb of the tendon. An effective method to pass this suture is to identify the superior limb of the canthal tendon first with small, toothed forceps placed into the incision. The forceps are passe along the medial side of the lateral orbital rim for a few mm until the dense fibers of the superior limb are located. While the tendon is held, the suture needle is passed through the tendon. The surgeon should pull on the two ends of the suture to enclosure that the suture is firmly attached to ligamentous tissue. The suture is then tied, with the lower lid drawn into position. Finally, subcutaneous sutures and 6-0 skin suture are placed along the horizontal lateral canthotomy. 50 4 Supraorbital Eyebrow Approach SURGICAL ANATOMY A previously popular incision used to gain access to the superolateral orbital rim is the eyebrow incision. No important neurovascular structures are involved in this approach, and it gives simple and rapid access to the frontozygomatic area. If the incision is made almost entirely within the confines of the eyebrow, the scar is usually imperceptible. Occasionally, however, some hair loss occurs, making the scar perceptible. Unfortunately, in individual who has no eyebrows extending laterally and inferiorly along the orbital margin, this approach is undesirable. Incisions made along the lateral orbital rim outside of the eyebrow are very conspicuous in such individuals, and another type of incision may be indicated. The main disadvantage of the approach is extremely limited access. TECHNIQUE Step 1. Vasoconstriction A local anesthetic with a vasoconstrictor is injected into the subcutaneous tissues over the lateral orbital rim to aid in hemostasis. Step 2. Skin Incision The eyebrow is not shaved. The skin is straddled over the orbital rim using two fingers and a 2 cm incision is made. The incision should be parallel to the hair of the eyebrow to avoid cutting hair shafts. Which might retard growth of the eyebrow hair. The incision may be made to the depth of the periosteum in one stroke (Fig. 4-1). The skin is freely movable in this plane. Access can be improved by extending the incision more anteriorly within the confines of the eyebrow. Extending the incision inferiorly along the orbital rim should be avoided because the incision crosses the lines of resting skin tension, making the scar very conspicuous. If more inferior exposure is required, the incision should extend laterally into a crow's foot wrinkle at least 6 mm above the level of the lateral canthus. 51 Figure 4 1 Placement of incision within confines of eyebrow hair. The incision is made through skin and subcutaneous tissue to the level of the periosteum in one stroke. 52 Step 3. Periosteal Incision After undermining in the supraperiosteal plane, the skin is retracted until it is over the area of interest. Another incision through the periosteum completes the sharp dissection (Fig. 4-2). Figure 4 2 Incision through periosteum along lateral orbital rim and subperiosteal dissection into lacrimal fossa. Because of the concavity just behind the orbital rim in this area, the periosteal elevator is oriented laterally as dissection proceeds posteriorly. 53 Step 4. Subperiosteal Dissection of Lateral Orbital Rim and Lateral Orbit Two sharp periosteal elevators are used to expose the lateral orbital rim on the lateral, medial (intraorbital), and, if necessary, posterior (temporal) surfaces (Fig. 4-2). Wide undermining of the skin and periosteum allows the tissues to be retracted inferiorly, providing better access to the lower portions of the lateral orbital rim. If one stays in the subperiosteal space, there is virtually no chance of damaging structures. Step 5. Closure The incision is closed in two layers, the periosteum and the skin. 54 5 Upper Eyelid Approach The upper eyelid approach to the superolateral orbital rim is also called upper blepharoplasty, upper eyelid crease, and supratarsal fold approach. In this approach, a natural skin crease in the upper eyelid is used to make the incision. The advantage of this approach is the inconspicuous scar it creates, which makes it one of the best approaches to the region of the superolateral orbital complex. SURGICAL ANATOMY Upper Eyelid In sagital section, the upper eyelid consists of at least five distinct layers: the skin, the orbicularis oculi muscle, the orbital septum above or levator palpebrae superioris aponeurosis below, Müller's muscle/tarsus complex, and the conjunctiva (Fig. 5-1). The skin, orbicularis oculi muscle, and conjunctiva of the upper eyelid are similar to those of the lower eyelid (see previous text). The upper eyelid differs from the lower eyelid, however, by the presence of the levator palpebral superioris aponeurosis and Müller's muscle. Orbital Septum/Levator Aponeurosis Complex. Deep to the orbicularis oculi muscle lies the orbital septum/levator aponeurosis complex. Unlike the situation in the lower eyelid, where the orbital septum inserts into the tarsal plate, in the upper eyelid the orbital septum extends inferiorly and blends with the levator aponeurosis approximately 10 to 15 mm above the upper eyelid margin. The levator muscle usually becomes aponeurotic at the equator of the globe in the superior orbit. The aponeurosis courses anteriorly to insert onto the anterior surface of the lower two thirds of the tarsal plate. Extensions of the levator aponeurosis also extend anteriorly into the skin of the lower portion of the upper eyelid. The aponeurotic portion of the levator behind the orbital septum is much wider than the muscle from which it is derived, and its medial and lateral extensions are known as horns or cornua. The lateral horn is prominent and deeply indents the anterior portion of the lacrimal gland to divide it into thin palpebral and thick orbital portions; its lateral extension attaches to the orbital wall at the orbital (Whitnall's) tubercle. The weaker medial horn of the levator aponeurosis blends with the orbital septum and the medial check ligament. 55 Figure 5 1 Sagittal section through orbit and globe. C=Palpebral conjunctiva; LA=levator palpebral superioris aponeurosis; MM=Müller's muscle; OO=orbicularis oculi muscle; OS=orbital septum; 56 Müller's Muscle/Tarsus Complex. Deep to the levator aponeurosis is Müller's muscle superiorly and the tarsus along the lid margin. Müller's muscle is a nonstriated, sympathetically innervated elevator of the upper eyelid. It takes its origin from the inner surface of the levator aponeurosis and inserts onto the superior surface of the upper tarsal plate. The tarsal plate of the upper eyelid is a thin, pliable fibrocartilaginous structure that gives form and support the upper eyelid. Embedded within the tarsal plate are large sebaceous glands, the tarsal or Meibomian glands. The edge of the tarsus adjacent to the free border of the lid parallels this, while the deeper (superior) border is curved so that the tarsus is somewhat semilunar in shape. It is also, of course, curved to conform the outer surface of the eyeball. The superior tarsus is considerably larger than the inferior one, the greatest height of the superior being about 10 mm and that of the inferior about 4 to 5 mm (see Figs. 2-5 and 2-6). The tarsal glands sandwiched between the layer of fibrocartilage in the upper eyelid exit on the lid margin near the lash follicles. The lashes are supported by their roots, attached to fibrous tissue on the tarsal plate, not in the orbicularis oculi muscle anterior to the tarsal plate. Laterally, the tarsal plate becomes a fibrous band that adjoins the structural counterpart from the lower lid, forming the lateral canthal tendon. Medially, the tarsal plate also becomes fibrous and shelters the superior lacrimal canaliculus behind as it becomes the medial canthal tendon. TECHNIQUE Step 1. Protection of Globe Protection of the cornea during operative procedures around the orbit is an excellent precautionary measure. If one is operating on the skin side of the eyelids to approach the orbital rim and/or orbital floor, a temporary tarsorrhaphy or scleral shell may be used after apllication of a bland eye ointment. These are simply removed at the completion of the operation. Step 2. Identification of and marking Incision Line Carefully evaluate the skin creases around the orbit. If tissues are edematous, the skin surrounding the opposite orbit can be used to obtain an appreciation for the direction of creases. If a lid crease is not readily detectable, a curvilinear incision along the area of the supratarsal fold that tails off laterally over the lateral orbital rim works well. The incision should be similar in location and shape to the superior incision in a blepharoplasty (Fig. 5-2). The incision, however, may be extended farther laterally as necessary for surgical access. The incision should begin at least 10 mm superior to the upper lid margin and be 6 mm above the lateral canthus as it extends laterally. The incision line is marked before infiltration of a vasoconstrictor. The tissues distort following infiltration, and therefore a perceptible crease may disappear after injection. Step 3. Vasoconstricton Local anesthesia with a vasoconstrictor is injected under the eyelid skin and orbicularis oculi muscle along the incision line. Additional vasoconstrictor solution is injected supraperiosteally in the area to be surgically exposed. 57 Step 4. Skin Incision The incision is through both skin and orbicularis oculi muscle (Fig. 5-2). The vaculature of the muscle maintains the viability of the skin when they are elevated together, and this leads to excellent healing. Figure 5 2 Position of incision. The incision may be extended farther laterally if necessary. The initial incision is made through skin and muscle. 58 Step 5. Underminig of Skin-Muscle Flap A skin-muscle flap is developed superiorly, laterally, and if necessary, medially, using scissor dissection in a plane deep to the orbicularis oculi muscle (Fig. 5-3). The dissection is carried over the orbital rim, exposing the periosteum. Figure 5 3 Sagittal section through orbit and globe showing dissection between orbicularis oculi muscle and the levator aponeurosis below and orbital septum above. 59 Step 6. Periosteal Incision The skin-muscle flap is retracted until the area of interest is exposed. The periosteum is divided 2 to 3 mm posterior to the orbital rim with a scalpel (Fig. 5-4). Figure 5 4 Incision through periosteum along lateral orbital rim and subperiosteal dissection into lacrimal fossa. To facilitate retraction of the skin/muscle flap, it can be widely undermined laterally and retracted with small retractors. Because of the concavity just behind the orbital rim in this area, the periosteal elevator is oriented laterally as dissection proceeds posteriorly. 60 Step 7. Subperiosteal Dissection of Lateral Orbital Rim and Lateral Orbit Periosteal elevators are used to perform subperiosteal dissection of the orbit and orbital rims (Fig. 5- 4). One must be cognizant of the lacrimal fossa, a deep concavity in the superolateral orbit. When reflecting periosteum from the lateral orbital rim into the orbit, one must turn the periosteal elevator so that it extends almost directly laterally inside the orbital rim. If the periostem is violated, the lacrimal gland will herniate through the periosteum into the surgical field. Step 8. Closure The wound is closed in two layers, periosteum and skin/muscle. 61 SECTION III CORONAL APPROACH 6 Coronal Approach The coronal or bi-temporal incision is a versatile surgical approach to the upper and middle regions of the facial skeleton, including the zygomatic arch. It provides excellent access to these areas with minimal complications (1). A major advantage is that most of the surgical scar is hidden within the hairline. When the incision is extended into the preauricular area, the surgical scar is inconspicuous. SURGICAL ANATOMY Layers if the Scalp The basic mnemonic for the layers of the scalp (Fig. 6-1) is : S = skin C = subcutaneous tissue A = aponeurosis and muscle L = loose areolar tissue P = pericranium (periosteum) The skin and subcutaneous tissue of the scalp are surgically inseparable, unlike these same structures elsewhere in the body. Many hair follicles and sweat glands are found in the fat just beneath the dermis. Also, no easy plane of cleavage exists between the fat and the musculoaponeurotic layer. The musculoaponeurotic layer, also inappropriately called the galea (which refers to aponeurosis only), consists of the paired frontalis (epicranius) and occipitalis muscle, the auricular muscles, plus a broad aponeurosis. The aponeurosis is the true galea and has two portions, an extensive intermediate aponeurosis between the frontalis and occipitalis muscles and a lateral extension into the temporoparietal region known as the temporoparietal fascia. Farther inferiorly, the temporoparietal fascia is continuous with the superficial musculoaponeurotic layer of the face (SMAS). The paired frontalis muscles originate from the galeal aponeurosis and insert into the dermis at the level of the eyebrows. An extension of the galea separates the two quadrilateral frontalis muscle in the middle of the forehead. The galea is a dense, glistening sheet of fibrous tissue, approximately 0,5 mm thick, stretching between the occipitalis and frontalis muscles. When the galea moves, the skin and fat move with it because of their close attachment. Laterally, the galea (or temporoparietal fascia as it is usually called) becomes less dense, but is still readily dissectable. The superficial temporal artery lies on or in this layer. The subgaleal fascia is the layer usually referred to as the "loose areolar layer" or the "subaponeurotic plane". This layer cleaves readily, allowing the skin, subcutaneous tissue 65 Figure 6 1 Layers of the scalp above the superior temporal line (top insert) and below the superior temporal line (right inset). Top inset : Skin, subcutaneous tissue, the musculoaponeurotic layer (galea in this illustration), the subgaleal layer of loose tissue, periosteum (pericranium), and bone of the skull. Right inset : Skin, subcutaneous tissues, the temporoparietal fascia (note temporal branch of VII N), the superficial layer of the temporalis fascia, a superficial pad of fat, the deep layer of temporalis fascia, the temporalis muscle above, the buccal fat pad below, skull. 66 musculoaponeurotic layers to be stripped from the pericranium.It is in this fascial plane that cleavage occurs during traumatic avulsion of the scalp. The loose tissue of the subgaleal fascia allows free movement of the skin over the periosteum when the frontalis muscle is contracted. Anatomic dissection have also revealed that the subgaleal frontalis muscle is contracted. Anatomic dissections have also revealed that the subgaleal fascia can be mobilized as an independent fascial layer. For the routine coronal approach to the fascial skeleton, however, this fascial layer is used only for its ease of cleavage. Anteriorly, the subgaleal fascia is continuous with the loose areolar layer deep to the orbicularis oculi muscles. Laterally, it is attached to the frontal process of the zygoma. This attachment continues along the superior surface of the zygomatic arch, above the external auditory meatus, and over the mastoid process. It terminates by fusing with the periosteum along the superior nuchal line. The pericranium is the periosteum of the skull. The pericranium can be elevated from the skull, although it is more firmly attached along cranial sutures. When released by subperiosteal dissection, the pericranium retracts owing to its elasticity. Layers of the Temporoparietal Region (see Fig. 6-1) The temporoparietal fascia is the most superficial layer beneath the subcutaneous fat. Frequently called the superficial temporal fascia or the zygomatic SMAS, this fascia layer is the lateral extension of the galea and is continuous with the SMAS of the face (Fig. 6-2). Because this fascia is just beneath the skin, it may go unrecognized after incision. The blood vessels of the scalp, such as the superficial temporal vessels, run along its outer aspect, adjacent to the subcutaneous fat. The motor nerves, such as the temporal branch of the facial nerve, run on its deep surface. Figure 6 2 Anatomic dissection of the temporal region showing temporoparietal fascia (lower forceps) and subgaleal fascia (upper forceps). Skin and subcutaneous tissues have been removed. Just deep to the subgaleal fascia is the temporalis fascia. 67 The subgaleal fascia in the temporoparietal region is well developed and can be dissected as a discrete fascial layer, although it is used only as a cleavage plane in the standard coronal approach (see Fig. 6-2). The temporalis fascia is the fascia of the temporalis muscle. This thick layer arises from the superior temporal line, where it fuses with the pericranium (see Fig. 6-1). The temporalis muscle arises from the deep surface of the temporalis fascia and the whole of the temporal fossa. At the level of the superior orbital rim, the temporalis fascia splints into the superficial layer attaching to the lateral border and the deep layer attaching to the medial border of the zygomatic arch. A small quantity of fat, sometimes called the superficial temporal fat pad, separates the two layers. Dissection through the medial layer of the temporalis fascia reveals another layer of fat, the temporal portion of the buccal fat pad, which is continuous with the other portion of the buccal fat pad of the cheek below the zygomatic arch. This fat pad separates the temporalis muscle from the zygomatic arch and from the other muscles of mastigation, allowing a smooth gliding motion during function. Temporal Branch of Facial Nerve The temporal branches of the facial nerve are often called the frontal branches when they reach the supraciliary region. The nerves provide motor innervation to the frontalis, the corrugator, the procerus, and, occasionally, a portion of the orbicularis oculi muscles. Nerve injury is revealed by inability to raise the eyebrow or wrinkle the forehead. The temporal branch or branches of the facial nerve leave the parotid gland immediately inferior to the zygomatic arch (Fig. 6-3). The general course is from a point 0,5 cm below the tragus to a point 1,5 cm above the lateral eyebrow (2). It crosses superficial to the zygomatic arch an average of 2 cm anterior to the anterior concavity of the external auditory canal, but in some cases, it is as near as 0,8 cm and as far as 3.5 cm anterior to the external auditory canal (Fig. 6-4) (3). As it crosses the lateral surface of the arch, the temporal branch courses along the undersurface of the temporoparietal fascia, and subgaleal fascia (see Fig. 6-1). As the nerve courses anterosuperiorly toward the frontalis muscle, it lies on the undersurface of the temporoparietal fascia (Fig. 6-5), and Figure 6- 3 Anatomic dissection showing branches of the facial nerve. Note the relationship of the temporal branch to the zygomatic arch (*). In this specimen, the branch crosses just anterior to the articular eminence of the temporomandibular joint. 68 Figure 6-4 Branches of the facial nerve. The distance from the anterior concavity of the external auditory canal to the crossing of the zygomatic arch (arrow) by the temporal branch varies from 8 to 35 mm. Figure 6- 5 Anatomic dissection showing position of the temporal branch of the facial nerve in relation to the temporoparietal fascia and zygomatic arch. The temporoparietal fascia is retracted inferiorly. The temporal branch of the facial nerve courses on its deep surface (or within the layer of fascia) anteriorly and superiorly (dashed lines), between the temporoparietal fascia and the fusion of the superficial layer of the temporalis fascia with the periosteum of the zygomatic arch. 69 enters the frontalis muscle no more inferiorly than 2 cm above the level of the superior orbital rim. It commonly branches into three or four rami long its course. The anterior branches supply the superior portion of the orbicularis oculi muscle and the frontalis muscle. The posterior branch innervates the anterior auricular muscles. The medial Orbit The medial orbital wall is composed of several bones: the frontal process of the maxilla, the lacrimal bone, the lamina papyracea of the ethmoid, and part of the lesser wing of the sphenoid. In terms of function, the medial orbit can be divided into anterior, middle, and posterior thirds. Anterior One Third of the Medial Orbital Wall. The medial orbital rim and the anterior one third of the medial orbit comprise the frontal process of the maxilla, the maxillary process of the frontal bone, and the lacrimal bone. The lacrimal fossa for the lacrimal sac lies between the anterior and posterior lacrimal crest. The anterior crest is a continuation of the frontal process of the maxilla. The posterior lacrimal crest is an extension of the lacrimal bone. The bone of the lateral nasal wall contains the nasolacrimal duct, which enters the nasal cavity through the inferior meatus located beneath the inferior turbinate. Middle One Third of the Medial Orbital Wall This part of the medial orbital wall, largely made of the lamina papyracea of the ethmoid bone, is thin, but is reinforced by the buttress effect of the ethmoid air cells. The only vascular structures of any significance are the anterior and the posterior ethmoidal arteries. The foramina for the anterior and posterior ethmoid arteries and nerves are found in, or just above, the frontoethmoid suture line at the level of the cribriform plate. The anterior ethmoid foramen is located approximately 24 mm posterior to the anterior lacrimal crest (4) (Fig. 6-6). The posterior ethmoid foramen or foramina (25% are multiple) are located approximately 36 mm posterior to the anterior lacrimal crest (4). The optic canal is located approximately 42 mm posterior to the anterior lacrimal crest. The distance between the posterior ethmoidal artery and the optic nerve is variable, but it is never less than 3 mm (4). Figure 6- 6 Medial orbital wall of the skull. Note the position of the anterior and posterior ethmoidal foramina (arrows). They are not located at the most superior portion of the orbit but at the level of the cribriform plate. 70 Posterior One Third of the Medial Orbital Wall. The posterior part of the orbit is made of thick bone surrounding the optic foramen and superior orbital fissure. TECHNIQUE The coronal approach can be used to expose different areas of the upper and middle face, The layer of dissection and the amount of exposure depend on the particular surgical procedure for which the coronal approach is used. In some instances, it may be prudent to perform a subperiosteal elevation of the flap from the point of incision. The periosteum is freed with a scalpel along the superior temporal lines as one proceeds anteriorly with the dissection, leaving the temporalis muscle attached to the skull. In most cases, however, dissection and elevation of the flap are in the easily cleaved subgaleal plane. For illustrative purposes, the following description is that of complete exposure of the upper and middle face, including the zygomatic arch, using a subgaleal dissection for most of the flap elevation. Step 1. Locating the Incision Line and Preparation Two factors are considered when designing the line of incision. The first is the hairline of the patient. In males, expected recession at the widow's peak as well as male pattern baldness should be contemplated. The incision for balding males might be placed along a line extending from one preauricular area to the other, several centimeters behind the hairline (Fig. 6-7), or even more posteriorly. Incision made farther posteriorly need not reduce access to the operative field, because Figure 6- 7 Incision placement for patients with male pattern hair recession. The incision is stepped posteriorly just above the attachment of the helix of the ear. The incision can be moved posteriorly as necessary. 71 the amount of skeletal exposure depends on the inferior extent of the incision, not on the anteroposterior position. In most females and nonbalding males, the incision may be curved anteriorly at the vertex, paralleling but remaining 4 to 5 cm within the hairline (Fig. 6-8). In children, the incision is preferably placed well behind the hairline to allow for migration of the scar with growth. If a hemicoronal incision is planned, the incision curves forward at the midline, ending just posterior to the hairline. Curving the hemicoronal incision anteriorly provides the relaxation necessary for retraction of the flap. Figure 6- 8 Incision placement for most female patients and males with no signs or family history of baldness. The incision is kept approximately 4 cm behind the hairline. 72 The second factor considered in designing the location of the incision is the amount of inferior access required for the procedure. When exposure of the zygomatic arch is unnecessary, extension of the coronal incision inferiorly to the level of the helix may be all that is necessary. The coronal incision can extended inferiorly, however, to the level of the lobe of the ear as a preauricular incision. This maneuver allows exposure of the zygomatic arch, temporomandibular joint (TMJ), and/or infraorbital rims. Extensive shaving of the head before incision is not medically necessary. In fact, direction of the hair shafts may be used as a guide for incision bevel to minimize damage to the follicles. The presence of hair makes closure more difficult, but does not seem to cause an increase in the rate of infection. A comb can be used to separate the hair along the proposed incision line. Long hair can be held in clumps with elastics placed either before or after sterile preparation. This measure minimizes the annoyance of loose hair in the operative field (Fig. 6-9). If shaving the hair is desired, it need not to be extensive - a small strip, approximately 12 to 15 ,,. Is adequate. The drapes can be sutured or stapled to the scalp approximately 1,5 cm posterior to the planned incision site, covering the posterior scalp and confining this hair. Figure 6- 9 Technique of gathering hair into clumps and securing the clumps with small elastics bands. Small bundles of the hair are twisted with the fingers and each is grasped in the middle with a hemostat loaded with an elastic band. The elastic band is rolled off the hemostat onto the hair bundle below the tips of the hemostat, which can be removed. 73 Step 3. Incision Cross hatches or dye markings across the proposed site of incision assist in properly aligning the scalp during closure. The first is made in the midline and subsequent marks are made laterally at approximately equal distances from the midline (Fig. 6-10). Crosshatches made with a scalpel tip should be deep enough (until bleeding) so that their location is visible at the end of the surgical procedure. The initial portion of the incision is made with a no. 10 blade or special diathermy knife, extending from one superior temporal line to the other. For routine coronal exposure, the incision is made through skin, subcutaneous tissue, and galea (see Fig. 6-10), revealing the subgaleal plane of loose areolar connective tissue overlying the pericranium. The flap margin may be rapidly and easily lifted and dissected above the pericranium. Limiting the initial incision through the temporalis fascia into the temporalis musculature, which bleeds freely. The skin incision below the superior temporal line should be to the depth of the glistening superficial layer of temporalis fascia. This depth is into the subgaleal plane, continuous with the dissection above the superior temporal line. An easy method to ensure that the incision is made to the proper depth is to bluntly dissect in the subgaleal plane from above, toward the zygomatic arch, with curved scissors and incising to that depth (Fig. 6-11). Preauricular extension of the incision is within a preauricular skin fold to the level of the lobule. The dissection severs the preauricular muscle and follows the cartilaginous external auditory canal, similar to the dissection described in Chapter 12. 74 Figure 6- 10 Draping of the patient and the initial incision. The drapes are secured with staples and/or sutures just posterior to the location of the planned incision. Cross-hatches are scored into the scalp at several locations for realignment of the flap during closure. The initial incision extends from one superior temporal line to the other, to the depth of the pericranium (see inset). The dissection will be in the subgaleal plane, which is loose connective tissue and cleaves readily. 75 Figure 6- 2 11 One technique for incising the scalp in the temporal region. Scissor dissection of the scalp in the subgaleal plane can proceed inferiorly from the previous incision made above the superior temporal line. While the scissors are spread, a scalpel incises to them, preventing the surgeon from incising the temporalis fascia and the muscle, which bleeds freely. 76 Step 4. Elevation of the Coronal Flap and Exposure of the Zygomatic Arch After elevation of the anterior and posterior wound margins for 1 to 2 cm, hemostatic clips (Raney clips) are applied or bleeding vessels are isolated and cauterized. Indiscriminate cauterization of the edge of the incised scalp can result in areas of alopecia and should be avoided. A technique to expedite clip removal before closure involves positioning an unfolded gauze sponge the cut edge of the scalp before clip application. The gauze can be pulled off the scalp before closure, removing the accompanying row of clips. In some instances, bleeding encountered during the procedures is from small emissary veins exiting through the pericranium or exposed skull. Cauterization, bone wax, or both are useful for these vessels. Figure 6- 12 Two methods of dissecting the flap in the subgaleal plane. Left, finger dissection readily cleaves the areolar tissue in the subgaleal plane. Several centimeters above the orbital rims, however, the pericranium is more tightly bound to the frontalis muscle and the periosteum may strip from the bone when using this technique in this location. Right, dissection with a scalpel. The flap is lifted gently with retractors and/or hooks to maintain gentle tension. The back (dull) edge of the scalpel rests on the pericranium and is swept back and forth, allowing the point of the scalpel to incise the subgaleal tissue. This technique is especially useful in flaps elevated for a second or third time, where adhesion in the subgaleal layer are more common and must be sharply incised. 77 The flap may be elevated atop the pericranium with finger dissection, with blunt periosteal elevators, or by back-cutting with scalpel (Fig. 6-12). As dissection proceeds anteriorly tension develops because the flap is still attached laterally over the temporalis muscles. Dissecting that portion of the flap below the superior temporal line from the temporalis fascia relieves this tension and allows the flap to retract farther anteriorly. Along the lateral aspect of the skull, the glistering white temporalis fascia becomes visible where it blends with the pericranium at the superior temporal line. The plane of dissection is just superficial to this thick fascial sheet. Dissection of the flap continues anteriorly in the subgaleal fascial plane to a point 3 to 4 cm superior to the supraorbital rims. A finger is used to palpate and locate the superior temporal lines, and a horizontal incision is made through pericranium from one superior temporal line to the other (Fig. 6-13). The surgeon should not extend the incision beyond the superior temporal line or the temporalis muscle will be cut and begin to bleed. A subperiosteal dissection then continues to the supraorbital rims. Figure 6-13 Incision of periosteum across the forehead from one superior temporal line to the other. The tension through periosteum should be 3 to 4 cm superior to the orbital rims. 78 Figure 6 -14 Anatomic dissection showing incision through the superficial layer of temporalis fascia (forceps) several centimeters above the zygomatic arch. Note the underlying fat between this layer of fascia and the deep layer of temporalis fascia. The tempoparietal fascia with the temporal branch of the facial nerve is folded inferiorly (below). The lateral portion of the flaps is dissected inferiorly atop the temporalis fascia. Once the lateral portion of the flap has been elevated to within 3 to 4 cm of the body of the zygoma and zygomatic arch, these structures usually can be palpated through the covering fascia. Near the ear, the flap is dissected inferiorly to the root of the zygomatic arch. The superficial layer of temporalis fascia is incised at the root of the zygomatic arch, just in front of the ear, and continues anteriorly and superiorly at a 45o angle, joining the cross-forehead incision previous made through pericranium at the superior temporal line. Incision of the superficial layer of temporalis fascia reveals fat and areolar tissue (Fig. 6-14). Further dissection inferiorly within this layer provides a safe route of access to the zygomatic arch, because the temporal branch of the facial nerve is always lateral to the superficial layer of temporalis fascia (Fig. 6-15). Metzenbaun scissors are used to bluntly dissect just under the superficial layer of temporalis fascia, within the space containing the superficial temporal fat pad (see Fig 6-15). Once the superior surface of the zygomatic arch and posterior border of the body of the zygoma are palpable or visible, an incision through periosteum is made along their superior surface. The incision progresses superiorly along the posterior border of the body of the zygoma and orbital rim, ultimately meeting the cross-forehead horizontal incision through pericranium. Subperiosteal elevation exposes the lateral surfaces of the zygomatic arch, body of the zygoma, and a lateral orbital rim (Fig. 6-16). To allow the flap to fold anteriorly, it may be necessary to continue the preauricular component inferiorly and to dissect the flap from the TMJ capsule. 79 Figure 6-15 Incision made through the superficial layer of the temporalis fascia. Incision begins at the root of the zygomatic arch (above the temporomandibular joint) upward and forward to join the incision made across the forehead in periosteum. One method to approach the posterior portion of the lateral orbital rim and superior surface of the zygomatic arch is also demonstrated. Dissection with incisors is continued deep to the superficial layer of temporalis fascia (see inset), within the superficial temporal fat pad, until bone is encountered. Sharp incision is then made through the periosteum on the superior surface of the zygomatic arch and the posterior surface of the zygoma. 80 Figure 6-16 Anatomic dissection showing the zygomatic arch (ZA) and body (ZB). The superficial layer of the temporalis fascia and periosteum is retracted inferiorly and anteriorly. Note the masseter muscle (MM) attachment to the inferior portion of the zygomatic arch. 81 Step 5. Subperiosteal Exposure of the Periorbital Areas To allow functional access to the superior orbits and/or nasal region, it is necessary to release the supraorbital neurovascular bundle from its notch or foramen. This maneuver involves dissecting in the subperiosteal plane completely around the bundle, including inside the orbit. If no bone is noted inferior to the bundle, the bundle can be gently removed from the bony bridge along the supraorbital rim to release the bundle (Fig. 6-17). Figure 6-17 Technique of removing bone inferior to the supraorbital foramen (when present) so the neurovascular bundle can be released. Relaxing incisions in the sagital plane through the elevated periosteum over the bridge of the nose are also shown. Use of this technique greatly facilitates dissection more inferiorly along the nasal dorsum. 82 Further retraction of the flap inferiorly may be accomplished by subperiosteal dissection into the orbits. The orbital contents attached to the lateral orbital tubercle are stripped, allowing dissection deep into the lateral orbit. Release of the periosteum around the inferior rim of the orbit allows exposure of the entire orbital floor and infraorbital region. Access to the infraorbital area is easiest after overlying tissue of the zygomatic arch and body are released to relax the overlying envelope. Dissection of the periosteum from the superior and medial orbital walls releases the flap and allows retraction down to the level of the junction of the nasal bones and upper lateral cartilages. This technique is facilitated by carefully incising the periosteum of the nasofrontal region (see Fig. 6-17). Dissection can proceed along the dorsum to the nasal tip, if necessary (Fig. 6-18). Figure 6-18 Dissection inferiorly to the top of the nose with a periosteal elevator. 83 The medial canthal tendons should not be inadvertently stripped from their attachments to the posterior and anterior lacrimal crest. They are identified as dense fibrous attachments in the nasolacrimal fossa (Fig. 6-19). The entire medial orbital wall may

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