Principles of Reconstructive Surgery - CVM 737A Lecture Notes PDF

CVM 737A Introduction to Surgery Principles of Reconstructive Surgery - SA Lecture 18 - 1 Lecture Hour January 16, 2025 R. Randall Thompson, DVM, MSpVM (SA Surgery) Liaison, DeBusk Veterinary Teaching Center Associate Professor of Small Animal Surgery ...

CVM 737A Introduction to Surgery Principles of Reconstructive Surgery - SA Lecture 18 - 1 Lecture Hour January 16, 2025 R. Randall Thompson, DVM, MSpVM (SA Surgery) Liaison, DeBusk Veterinary Teaching Center Associate Professor of Small Animal Surgery  Learning Objectives 1. List Methods of reducing tension when closing a wound surgically. 2. Summarize the direction that surgical incisions should be made and why. 3. Summarize the considerations made when planning the surgical removal of a skin tumor. 4. Summarize the methods for recruiting skin to close wounds under tension. 5. Illustrate methods used for preventing or correcting “Dog ears,” or puckers. $249.95 By Michael M. Pavletic ISBN Number: 978-1394209484 E-book also available Publication May 2018 5th Edition August 2025  Reconstructive Surgery Commonly performed to… Close defects that occur secondary to trauma Correct or improve congenital abnormalities After removal of neoplasms It is important to select the appropriate technique or techniques to prevent complications and avoid unnecessary cost.  Reconstructive Surgery Large or irregular defects sometimes can be closed using relaxing incisions or “plasty” techniques (e.g., V-to-Y plasty, Z-plasty). Large defects or those on the extremities may require that tissue be mobilized from other sites. Pedicle flaps are tissues that are partly detached from the donor site and mobilized to cover a defect Grafts involve the transfer of a segment of skin to a distant (recipient) site.  Reconstructive Surgery Careful planning and meticulous, atraumatic surgical techniques are necessary to prevent… Excessive Tension Kinking Circulatory Compromise The amount of skin available for transfer varies between sites on the same animal and between breeds. Little skin can be mobilized in the extremities. Advancing adjacent tissue often can close large defects over the trunk.  Reconstructive Surgery The character of the recipient bed influences the choice of reconstructive technique. Properly developed and transferred local flaps can survive on avascular beds Grafts and distant flap transfers require vascular beds (i.e., healthy granulation tissue, muscle, periosteum, and paratendon).  Hirudiniasis Attachment of leeches to skin Recommended only for tissues with impaired venous circulation. Medicinal leech is Hirudo medicinalis. Leeches produce a small bleeding wound that mimics venous outflow. The leech eats an average of 5 ml of blood, but blood oozes from the wound for 24 to 48 hours after the leech detaches because of anticoagulants and vasodilator substances introduced into the wound. Significant risk of infection with Aeromonas hydrophila when leeches are used. Hirudiniasis  Tension Lines and Tension Relief When planning reconstructive surgery, consider… Location of the wound Elasticity of surrounding tissue Regional blood supply Character of the wound bed - infection tissue - granulation Skin availability -  Tension Lines and Tension Relief Grasping and lifting the skin in the proposed flap or graft area and allowing it to retract spontaneously assesses skin tension and elasticity. Evaluating the amount of tension that can be tolerated by tissue is subjective. Apposing incision edges under too much tension causes incisional discomfort and pressure necrosis, resulting in sutures “cutting out” and partial or complete incisional dehiscence.  Tension Lines and Tension Relief Methods of reducing tension include… Undermining wound edges Selecting appropriate suture patterns > - X cruciate for↓ tension simple interrupted Using relief incisions Skin stretching Tissue expansion  Tension Lines and Tension Relief Animal is always positioned for surgery, such that mobile skin is not pinned against the table or otherwise immobilized. Using pads, flexing the appropriate joints, avoiding excessive tension with table ties may accomplish this. If these methods do not allow primary apposition, wounds may be allowed to heal by secondary intention or may be reconstructed with flaps or grafts.  Tension Lines Tension lines are formed by the predominant pull of fibrous tissue within the skin. General lines of tension have been mapped in animals, but variations occur based on… Breed Conformation Gender Age  Tension Lines Tension causes incised skin edges to separate and widens linear scars. Incisions should be made parallel to tension lines. ⑪ Incisions and wounds along tension lines heal better, faster, and with more aesthetic results. Incisions made across tension lines tend to gape.  Tension Lines & Incisions should be made parallel to tension lines. Incisions made at an angle to tension lines take a curvilinear shape. Incisions made across tension lines require more sutures for closure and are more likely to dehisce than those made parallel to tension lines.  Tension Lines – Good to Know ⑪ Traumatic wounds should be closed in the direction that prevents or minimizes tension. Wound edges should be manipulated before closure to determine which direction the suture line should run to minimize tension. If tension is minimal, a wound should be closed in the direction of its long axis. The direction of closure should prevent or minimize the creation of “dog ears,” or puckers, at the ends of suture lines.  ⑧ Approximate skin tension lines in dogs. Incisions made across tension lines. incisionto Obligea · Il to incision line minimum tension/gape = not ideal Perpendicular (A) or oblique (B) incisions gape and require more sutures for closure than incisions that parallel skin tension lines (C). Wound edges should be manipulated to determine the direction of least tension and minimal “dog ear” formation. A. Wound edges showing little tension and small dog ears. B. Wound edges showing greater tension and large dog ears.  Tension Relief Undermining skin adjacent to a wound Skin is undermined by using scissors to separate the skin or panniculus muscle (or both) from underlying tissue. Simplest tension-relieving procedure. Releases skin from underlying attachments so that its full elastic potential can be used. Skin should be undermined deep to the panniculus muscle layer to preserve subdermal plexus and direct cutaneous vessels that run parallel to the skin surface. Undermining skin adjacent to a wound. Before wound closure, use scissors to undermine skin and subcutaneous tissue or skin and panniculus muscle and to separate them from the underlying tissue. Insert closedScissors into tissue then open - ,  Bleeding usually is insignificant during undermining. Excessive bleeding may be controlled with electrocoagulation or ligation Skin tension and bandaging usually control hemorrhage and prevent seromas.  Prevent subdermal plexus injury Use an atraumatic surgical technique… Cut skin with a sharp scalpel blade instead of scissors Avoid crushing instruments (e.g., Allis tissue forceps) Manipulate skin with… Brown-Adson thumb forceps Skin hooks Stay sutures  Preserving Cutaneous Circulation Things that interfere with cutaneous circulation… S Wound closure under excessive tension Rough surgical technique Division of direct cutaneous arteries Superficial Ed epigastric -. a axillary - a May cause… Skin necrosis Wound dehiscence Infection  Preserving Cutaneous Circulation Surgical manipulation of recently traumatized skin should be minimized until circulation improves. Resolution of contusions, edema, and infection indicates improved skin circulation. 28-48 his to truly evaluate - - blood supply/tissue effect  Skin Stretching and Expansion Technique used in reconstructive surgery that takes advantage of the skin's ability to stretch beyond its natural or inherent elasticity. Skin can be prestretched hours to days before surgery to allow closure with less tension at the time of the procedure. Presuturing, adjustable sutures, skin stretchers, and skin expanders are used in this technique.  Skin Stretching and Expansion Technique used in reconstructive surgery that takes advantage of the skin's ability to stretch beyond its natural or inherent elasticity. Skin can be prestretched hours to days before surgery to allow closure with less tension at the time of the procedure.  Skin Stretching and Expansion Methods for recruiting skin to close wounds under tension include… Presuturing Adjustable sutures Skin stretchers Skin expanders  Presuturing horizontal suggest - mattress pattern Performed 24 hours before surgery.  (artificial) Skin Stretchers Noninvasive device capable of stretching skin both adjacent to and distant from the surgical site. More skin can be stretched or recruited using this technique than by presuturing or tissue expanders. Sufficient skin may be recruited within 24 to 48 hours although 96 hours may be required.  Inflatable Tissue Expanders Inflated in subcutaneous tissue to stretch overlying skin. Expanders have an inflatable bag and reservoir. Gradual expansion involves injecting to a given pressure or volume at intervals spanning days to weeks (usually every 2 to 7 days). When the tissue is sufficiently stretched to allow may give NSAID A patent to discomfort reconstruction, the device is - removed and a skin flap is created to close the defect.  Adjustable Sutures 7 suture pulled/tightened button & through held camp Clamp ratchets tighter Skin Stretching and Expansion & Axial pattern flaps are preferable to tissue expanders for large wound reconstruction.  Suture Patterns Subdermal Sutures > - close dead space Walking Sutures > - edges together advance Skin External Tension Relieving Sutures  Subdermal Sutures Subdermal fascia is strong and tolerates tension better than subcutaneous tissue or skin. Sutures placed in subdermal or subcuticular tissue reduce tension on skin sutures and bring skin edges into apposition. Also reduce scarring. For subdermal and subcuticular sutures, 3-0 or 4-0 polydioxanone, poliglecaprone 25, or polyglyconate suture with a buried knot is used.  Walking Sutures Move skin across a defect Obliterate dead space Distribute tension over the wound surface Skin is advanced toward the center of the wound by placing rows of interrupted, subdermal sutures beginning at the depths of the wound. Suture should be placed through fascia of the body wall at a distance closer to the center of the wound than the bite through the subdermal fascia or deep dermis.  Walking Sutures advance skin toward the center of the wound. A. Place the suture through the fascia of the body wall at a distance closer to the center of the wound than the bite through the subdermal fascia or deep dermis. B. Note that the distance from a to b increases because of skin stretching when the suture is tied.. https://vimeopro.com/cvmess/surgical-pearls/video/377636689  External Tension Relieving Sutures Help prevent sutures from cutting out, which occurs when pressure on skin within the suture loop exceeds the pressure that allows blood flow. Pressure is reduced by spreading it over a larger area of skin. Placing sutures farther from the skin edge or using mattress or cruciate sutures helps disperse pressure. Other suture patterns that relieve tension. Standard tension-relieving suture for the skin is the vertical mattress suture. A tension-relieving row of vertical mattress sutures should be placed 1 to 2 cm away from the primary row of sutures apposing the skin edges. The vertical mattress sutures are placed while the skin is approximated with towel clamps or skin hooks before apposition of the skin edges with approximating sutures. Tension-relieving vertical mattress sutures usually can be removed by the third day after surgery, when collagen fibers have reorganized and fibrin has stabilized the wound edges.  Stents Cartonagainsa stent · vertical mattress > - may place simple interrupted in bln if primary closure space Placing padded material Commercial stent - Penrose Drain Jcheaper - beneath the suture loops is tubing cut of IV piece - stenting. Other suture patterns that relieve tension. Alternating wide and narrow bites using simple interrupted sutures Placing pulley sutures, such as “far-near-near-far” or “far-far-near-near” patterns. Horizontal mattress sutures with or without rubber tubing stents may be used Greater potential for impairing local cutaneous blood flow to the skin edges.  Prevention of “Dog Ears” “Dog ears,” or puckers, may be prevented or corrected at the end of a suture line by… Placing sutures close together on the convex side of the defect and farther apart on the concave side. Outlining with an elliptic incision, removing redundant skin, and apposing the skin edges in a linear or curvilinear fashion.  Prevention of “Dog Ears” “Dog ears,” or puckers, may be prevented or corrected at the end of a suture line by… Dog ear may be incised in the center to form two triangles; one triangle should be excised and the other used to fill the resultant defect. Both triangles may be excised and the edges apposed, creating a linear suture line  Prevention of “Dog Ears” Thin elastic skin is less prone to the formation of dog ears than thick skin. Many dog ears flatten without excision.  Prevention of “Dog Ears” Prevent or correct “dog ears” or puckers at the end of suture lines by using unequal suture spacing.  Prevention of “Dog Ears” - don't close elliptical incision b continuous pattern (oo symmetrical) Prevent or correct “dog ears” or puckers at the end of suture lines by resecting an elliptic segment of skin.  Prevention of “Dog Ears” fa a usethis Y Split here removep Prevent or correct “dog ears” or puckers at the end of suture lines by resecting one large triangle of skin.  Prevention of “Dog Ears” T split here a bothfast Prevent or correct “dog ears” or puckers at the end of suture lines by resecting two smaller triangles of skin.  Relaxing Incisions Allows skin closure around fibrotic wounds or over important structures… Before radiation therapy After extensive tumor excision They are rarely indicated except… On distal extremities Around the eyes and anus To cover tendons, ligaments, nerves, vessels, or implants.  Simple Relaxing Incisions Relief incisions heal by contraction and epithelialization in 25 to 30 days. Some relaxing incisions surrounded by loose elastic tissue can be closed primarily after the wound is approximated. Multiple Punctate Relaxing Incisions Multiple punctate relaxing incisions are small, parallel, staggered incisions made in skin adjacent to a wound to allow closure with reduced tension. Multiple punctate relaxing incisions are more cosmetic than single relaxing incisions but provide less relaxation and have a higher risk of causing significant circulatory compromise.  Make relaxing incisions near the defect to allow skin apposition... After undermining the skin, unilateral or bilateral simple relaxing incisions are made adjacent to the wound.  Make relaxing incisions near the defect to allow skin apposition... After preplacing a continuous subcuticular suture pattern, multiple punctate incisions are made parallel to the wound.  V-to-Y Plasty tryingto wound (but need more Skin) ~ slide Skin N close espace just placedt up Provides an advancement flap to cover the wound.  to S" Z-Plasty "Z.. ~ 2 Can be made adjacent to or involving the wound to allow wound closure. Z-Plasty  Z-Plasty (Think: Z to S Plasty) Can be made adjacent to a wound to reduce tension on the wound and facilitate wound closure. Central member of the Z is… parallel to the greatest lines of tension (perpendicular to the incision you are closing). 1/3 to 1/2 the length of the incision you are closing. Cut a 60° angle on “limbs” of the Z (Toward the center of the Z)  Z-Plasty (Think: Z to S Plasty) Usually ≥ 3 cm from the primary incision Tips of “Z” can be rounded to avoid necrosis Undermine the tissue under… The Z-plasty Both sides of the primary incision you are closing The skin in between the two incisions.  Removal of Skin Tumors Before a tumor is removed, skin tension and elasticity should be assessed, but excessive tumor manipulation should be avoided. Direction of skin tension lines, shape of the excision, and method of closure should be planned before surgery. A large area should be clipped and aseptically prepared for surgery, especially if there is a chance that skin flaps may be needed for closure. Excision of skin tumors should include the tumor, previous biopsy sites, and wide margins of normal tissue in three dimensions (i.e., length, width, and depth).  Removal of Skin Tumors ⑪ Benign tumors, remove the tumor and 1 cm of normal tissue Malignant tumors, a margin of more than 2 to 3 cm may be necessary for complete local excision. These margins are taken in all dimensions, including the deep margin if feasible.  Removal of Skin Tumors The margin distance should be greater for aggressive, infiltrative tumors… Mast Cell Tumors Melanomas Squamous cell carcinomas Soft tissue sarcomas Feline Mammary Adenocarcinomas Hemangiopericytomas Infiltrating lipomas  Removal of Skin Tumors Tumor invasion is affected by the type of surrounding tissue. Tissue easily infiltrated by tumor cells (i.e., fat, subcutaneous tissue, muscle, and parenchyma) should be resected with the tumor.  Removal of Skin Tumors ⑪ Cartilage, tendon, ligaments, fascia, and other collagen-dense, vascular-poor tissues are resistant to neoplastic invasion and therefore often are spared during resection. Excision of infiltrative or aggressive tumors should extend at least one fascial layer below the detectable tumor margins.  ⑪ Removal of Skin Tumors Radical tumor excision (i.e., removal of an entire compartment or structure, amputation, or lobectomy) is indicated for poorly localized tumors or those with high-grade malignancy.  Removal of Skin Tumors Good to Know ⑪ Excision of infiltrative or aggressive tumors should include greater than 2 to 3 cm of “normal” tissue around the lesion. Extend the dissection at least one fascial layer below the detectable tumor margins. Local tumors most often recur because the surgical margins for the original tumor were inadequate; be sure to mark tumor borders.  Removal of Skin Tumors A surgical marker was used to delineate a 2- to 3-cm margin for excision of a malignant tumor involving the skin and subcutaneous tissues. Removal of Tumors Removal of Tumors Removal of Tumors  Skin Flaps for Wound Closure Advancement Flaps Rotational Flaps Transposition Flaps Interpolation Flaps Tubed Pedical Flaps  Advancement Flaps Local subdermal plexus flaps. Include… Single-pedicle Bipedicle H-plasty V-Y advancement flaps Flaps are formed in adjacent, loose, elastic skin that can be slid over the defect. An advancement flap is developed parallel to lines of least tension.  V-to-Y Plasty Provides an advancement flap to cover the wound.  definitions of know flaps a anything - different Rotational Flaps bold about them in ↳ Local flaps that are pivoted over a defect with which they share a common border. Semicircular and may be paired or single. May be used to close triangular defects without creating a secondary defect. A curved incision is created, and the skin is undermined in a stepwise fashion until it covers the defect without tension.  Rotational Flaps The forelimb skin fold is harvested to close axillary or sternal wounds. A. Grasp loose skin from the elbow to the body wall to determine the amount of skin that can be harvested. Dashed lines indicate incisions to create lateral and medial skin incisions to define the width of the flap, then connect the incisions with a crescent-shaped incision proximal to the elbow. B & C. Elevate, transpose, and suture the flap into the wound, then close the donor site. D. Create bilateral flaps to close larger wounds.  Transposition Flaps Transposition flaps are rectangular, local flaps that bring additional skin when rotated into defects. Ninety-degree transposition flaps are aligned parallel to the lines of greatest tension to obtain the bulk of the flap required to cover the defect.  Transposition Flaps The width of the flap equals the width of the defect. The length of the flap is determined by measuring from the pivot point of the flap to the most distant point of the defect Length decreases as the arc of rotation increases past 90 degrees because of kinking and skin folding. Dog ears occur but flatten with time.  Transposition Flaps Use a rotational or transposition flap to cover defects with mobile skin in a plane different from the defect.  Interpolation Flaps A variation of the transposition flap, the interpolation flap differs in that it lacks a common border with the wound. This leaves an area of interposed skin between the donor bed and the recipient wound. The flap is created in the same way as a transposition flap except that the length of the interpolation flap must include the length of the intervening skin segment.  Interpolation Flaps The subcutaneous tissue on the segment of flap overlying the intervening skin is left exposed. After approximately 14 days, this redundant segment of the flap is resected and the incised edges are sutured. As an alternative, a bridge incision can be made connecting the donor and recipient beds to facilitate flap transfer, which eliminates the need for a second surgical procedure.  Tubed Pedical Flaps A tubed pedicle flap uses a multistaged procedure to “walk” an indirect, distant flap to a recipient site. This is an advanced procedure and should be performed by a specialist.  Tubed Pedical Flaps A. Make two parallel dorsoventral incisions and undermine skin to create a pouch. B. Position the limb inside the pouch and suture the edges of the defect to the flap. C. After 2 to 3 weeks, release the limb and cover the remainder of the defect. A. Make two horizontal incisions to free the flap, then suture it to the remaining edges of the defect. B. Close the donor site.  Axial Pattern Flaps Include a direct cutaneous artery and vein at the base of the flap. Terminal branches of these vessels supply the subdermal plexus. T Have better perfusion than pedicle flaps with a circulation from the subdermal plexus alone. Axial pattern flaps are elevated and transferred to cutaneous defects within their radius.  Direct cutaneous vessels used in axial pattern flaps. 1. Caudal auricular 2. Omocervical 3. Thoracodorsal 4. Caudal superficial epigastric 5. Medial genicular 6. Deep circumflex iliac 7. Superficial lateral caudal (inset) 8. Superficial brachial (inset) 9. Superficial temporal. Dashed lines outline anticipated flaps corresponding with each direct cutaneous vessel (neither a cranial superficial epigastric flap nor a reverse saphenous conduit flap is shown).  Direct cutaneous vessels used in axial pattern flaps. A thoracodorsal axial pattern flap has been tubed and applied over an elbow wound.  Caudal Superficial Epigastric Flap Concurrent ovariohysterectomy is recommended because transposed glands remain functional. Mammae may be resected later if their appearance is objectionable.  Skin Grafts Generally considered an advanced procedure that should be performed by a specialist. Full Thickness Grafts Sheet Grafts Plug, Punch, or Seed Grafts and Strip Grafts Mesh Grafts Split Thickness Skin Grafts  Skin Grafts Skin grafts may be meshed by making small, full- thickness incisions through the graft. The incisions are aligned in parallel rows.  Small Animal Surgery Fifth Edition CHAPTER 15 Theresa Welch Fossum, DVM, MS, PhD Laura Pardi Duprey Copyright © 2018 by Mosby, Inc. an affiliate of Elsevier Questions?