MODULE 21 Neurosurgery RPN2023.pdf

MODULE 21: Neurosurgery Suggested Readings Alexander’s Care of the Patient in Surgery ( 2 0 22 ) Chapter 21 Tighe (2015) Instrumentation for the Operating Room Chapter 99, 110 ORNAC Standards 2023 Lea...

MODULE 21: Neurosurgery Suggested Readings Alexander’s Care of the Patient in Surgery ( 2 0 22 ) Chapter 21 Tighe (2015) Instrumentation for the Operating Room Chapter 99, 110 ORNAC Standards 2023 Learning Outcomes Explain relevant anatomy and basic procedural considerations for neurosurgery. Differentiate between a subdural and epidural hematoma. Compare and contrast a burr hole, craniotomy, and stereotactic brain surgery. Describe ventriculoperitoneal shunts and transphenoidal for pituitary pathology. Neurosurgery is performed for head injury, tumors, vascular disorders, hydrocephalus, epilepsy, and Parkinson’s disease. Neurosurgery also treats disorders of the spine (trauma and fractures, tumors, disk disease), and peripheral nerve disorders (chronic pain). Anatomy The nervous system is divided structurally into the central nervous system (CNS) consisting of the brain and spinal cord and the peripheral nervous system (PNS) consisting of the neurologic structures such as the cranial and spinal nerves. The brain is protected by the skull and has 5 distinct connecting parts: the cerebrum, the midbrain, the cerebellum, the pons, and the medulla oblongata. Cerebrum - Divided by a longitudinal fissure into 2 hemispheres (right and left). The right side controls the left side of the body and vice-versa. Each hemisphere is divided into 4 main lobes: Frontal- area of intellect/personality and terminus for motor and sensory nerves Parietal- sensation, pain, pressure and interpretation of same Temporal- speech, hearing, comprehension of same Occipital- vision Brain stem (midbrain) – Consists of the midbrain, pons and medulla oblangata. The brain stem controls basic vital functions (HR, respiration, & controls wakefulness). Injury here can be Module 21: Neurosurgery  life threatening! Cerebellum - Lies in the posterior fossa; posterior to the brain stem. This area is responsible for fine coordinated movements and balance. Skull - Provides protection for the brain and is comprised of mainly 8 bones: 2 temporal, 2 parietal, frontal, occipital, ethmoid and sphenoid. The bones of the skull are joined by bone seams called sutures. The skeletal surface landmarks of the skull can be palpated and are commonly used as landmarks used to plan surgical approaches. Many important structures such as the sella turcica which houses the pituitary gland are located in this area. Meninges – Three membranes that completely envelope the brain and spinal cord. Layers from superficial to deep: 1. DURA – tough, double layered. Important for its blood supply. Between its two layers run several arteries. One of these is the MIDDLE MENINGEAL ARTERY. Rupture of this artery (ie. blunt force to the skull) may cause an epidural hemorrhage. 2. ARACHNOID – cerebral spinal fluid (CSF) found in this layer. The sub- arachnoid space is continuous with the four ventricles of the brain. 3. PIA – acts like a gossamer web over brain tissue. Specialized cells here called the choroid plexus produce CSF into the sub-arachnoid space. **THE CRANIAL MENINGES ARE LOCATED BETWEEN THE SKULL AND THE BRAIN** Ventricular system – Within the brain are four communicating cavities or ventricles filled with Cerebrospinal fluid (CSF). The brain contains two lateral ventricles. A third ventricle is connected to the lateral ones by small openings, and is also connected to the fourth ventricle. There are openings from the fourth ventricle which communicate to the subarachnoid space and CSF can circulate from one to the other. CSF - The meningeal membranes and the spaces filled with fluid, form a pad enclosing the brain and spinal cord. The CSF serves to keep the brain and spinal cord moist, and protected from various pressures by absorbing some of the force of external trauma. Cranial Nerves -The 12 cranial nerves emerge directly from the brain stem. They are delicate and at risk of damage during surgery. The facial nerve is anatomically close to the auditory nerve and can be at risk of injury in ENT surgery. Cerebral Blood Supply - The arterial blood supply to the brain enters the cranium through the two internal carotid arteries (Anterior) and the two vertebral arteries (posterior). Anterior circulating meets the posterior circulation at the Circle of Willis (COW). Module 21: Neurosurgery  Pathophysiology of Brain Tumour Brain Tumour - An abnormal mass, as the result of increased multiplication or uncontrolled growth of cells. Brain tumours can be benign or malignant, and may or may not be completely removed based on its proximity to vital areas of the brain. Benign tumour – Mass that is made up of slow growing cells. Malignant tumour - Mass that is comprised of fast-growing cells, that often infiltrate normal brain structures and are difficult to remove surgically. Primary tumours [both benign and malignant] do not usually spread to other parts of the brain or spinal cord. A primary brain tumour is a tumour that has arisen within the brain tissue itself. Secondary brain tumour is one that has arisen elsewhere in the body and has spread to the brain. These tumours are also referred to as metastatic tumours and can travel from other organs such as the breast, lung, kidney, skin etc. Perioperative Nursing Considerations Nursing Assessment Special care is given to pad the patient’s pressure points well, as neurosurgery cases are often long (3-8 hours). Patients need to be well secured on the OR bed as the table will be tiled during surgery. Other risks to the neurosurgery patient include: Risk for infection related to surgical incision, urinary catheters, intravenous lines, and reduced cardiac function Risk for bleeding related to surgical incision, tissue dissection, and hypothermia Risk for impaired skin integrity related to surgical duration, positioning and hypothermia Blood Replacement- Neuro surgery requires tissue dissection of highly vascular areas, resulting in the need for blood transfusion. Consent, blood type, orders and availability of blood products must be confirmed pre-, intra-, and post-operatively. The RPN should be prepared in the scrub role with hemostatic agents, such as hemoclips, sutures, ties, sponges, Gelfoam, Surgicel, etc to anticipate any critical surgical needs. Patient Positioning – The most common positions used in neurosurgery are: supine, lateral or prone. The patient’s head is supported by a head ring/headrest or neurosurgery headrest and skull clamps, such as a Mayfield head fixation device. The Mayfield headrest or similar fixation devices attaches to the frame of the OR bed after the standard OR bed headpiece has been removed. Refer to the ORNAC Standards and the positioning performance checklist for appropriate practices. Module 21: Neurosurgery  Other positioning devices, such as pillows, blankets, gel pads, a safety belt, tape, a shoulder roll, an axillary roll, a beanbag, and chest roll may be used. The patient position and the associated positioning devices may vary depending on the surgeon’s preferences and available institutional resources and policies. It is recommended that the perioperative nurse collaborates with the surgical team to ensure that the patient is positioned safely before, during, and after surgery. The perioperative nurse ensures that the patient return electrode pad is applied and the safety strap secured. Instrumentation and Counting Love adson (periosteal elevator) Bayoneted Instruments Penfield dissector Dandys (sideways curved snaps) Raney clip appliers (for scalp hemostasis) Hudson brace (to make burrholes) Aneurysm clip applier (used to clip an aneurysm) Bipolar cautery forceps (bayoneted for visibility) Special sponges called patties are used (radiopaque) - have strings for identification and should be moistened before using on the brain Non-absorbable nylon suture (surgilon) used on dura – taper needle Absorbable suture (polysob) used on galea – cutting needle Hemostatic agents used: bone wax, surgicel, gelfoam, and floseal ICP/EVD monitors for post-operative monitoring of patient with hydrocephalus. Hemovac/JP Drains - following drainage of subdural hematoma All neurosurgery procedures require a minor count. Initial Count (minor) → Closing “Dura” Count (minor) → Final Count (minor) Equipment OR Bed and Attachments – A specialized OR bed, such as a Jackson table or Andrews table or frame may be required. Skull clamps, skill pins, and tongs are commonly used for craniotomies and posterior cervical spine surgeries to stabilize the head and neck. Module 21: Neurosurgery Microscope – Provides intense light and up to 12-fold magnification to areas of the brain, spine, and peripheral nerves, allowing for greater precision when operating. Drills – Commonly used equipment in neurosurgery, powered by nitrogen/air driven or electric. A perforator bit used to create burr holes. A cutting blade used to make the skull flap. The L- Shaped attachment of the drill is used to protect the dura. Forced-Air Warming Blankets – Used to prevent hypothermia in neurosurgery. Majority of surgeries are long procedures, lasting 3-8 hours. There must be a continuous assessment of patient’s temperatures to ensure normothermia intraoperatively. Endoscope – Used for MIS technique in neurosurgery, providing illumination and magnification of structures and an extended viewing angle. Intra-operative Radiology (Fluroscopy) – Commonly used in spinal surgeries. Ensure patient is placed on a OR bed compatible with fluoroscopy. The patient should be protected from undue radiation exposure. Ultrasonic Aspirator (Cavitron Ultrasonic Surgical Aspirator (CUSA)) – Used to emulsify and debulk a tumor with high-frequency sound waves. Surgical Interventions Craniotomy – The removal of a section of the cranium referred to as a bone flap exposing areas of the brain for indicated repair: Brain tumours Bleeding [hemorrhage] or blood clots [hematomas] from injuries (Epidural & Subdural) Cerebral aneurysms - Often asymptomatic until they rupture/bleed. C/O “worst headache of my life”. When possible, aneurysms are coiled. A catheter is fed through the femoral artery in the leg. Tiny coils are threaded through the catheter into the aneurysm wall. Prevents blood flow into the aneurysm thus preventing rupture. Arteriovenous malformation (AVMs) - Tangle of abnormal and poorly formed blood vessels (arteries and veins). They have a higher rate of bleeding than normal vessels. Brain abscesses Epilepsy Neurological disorders (Parkinson’s Disease) Hydrocephalus Sugita pins and a Mayfield fixation device are often used in neurosurgery to prevent any Module 21: Neurosurgery  movement of the head (see image below). Sugita Pin Sugita Fixation Device Craniotomies are performed under general anaesthesia or with the patient fully awake. Indications for awake craniotomies, include surgery involving eloquent areas of the brain (motor/sensory cortex). Mapping of these eloquent areas is conducted to prevent postoperative deficit ie. resection of a tumour on the motor cortex. Burr Holes – Minimum exposure that can be made to gain access to the brain. They are placed in the skill to remove a localized fluid collection (causing pressure on the brain) secondary to head trauma that results in an epidural or subdural hematoma (surgical emergency). EPIDURAL - Collection of blood above the dura. Caused by a laceration to the middle meningeal artery (blunt force to the skull). SUBDURAL - Collection of blood below the dura. Results from venous bleeding and collects more slowly. Bridging veins in the subdural space are torn. There are several layers that require dissection before creating a Burr Hole or Craniotomy 1. Skin incision made (Raney clips used for hemostasis of scalp) & subcutaneous tissue. May inject local anesthetic with epinephrine to control bleeding ‘vasoconstriction’ 2. Galea (tough aponeurosis) Module 21: Neurosurgery  3. Pericranium (periosteum) – Love adson used (elevator) 4. Skull 5. Dura Once the skull is exposed, a burr hole is created with a perforator burr using a Hudson brace, or air/nitrogen/electric drill. The burr hole allows for the hematoma to drain, thus relieving pressure on the brain. Sometimes a drain is left in (JP/Hemovac). Shunt Insertion for Hydrocephalus Hydrocephalus is a condition marked by an excessive accumulation of CSF resulting in dilation of the ventricular system and increased intracranial pressure (ICP). The insertion of a shunt allows for CSF to be drained. An external ventricular drain (EVD) is inserted through a burr hole into the ventricle and placement is confirmed with the pressure of CSF. The distal end of the shunt is tunneled beneath the scalp, and the externalized end of the catheter is connected to an external drainage system. The shunt is left in until the hydrocephalus is resolved. If the hydrocephalus is not resolved and the hydrocephalus is long-term, then a Ventriculoperitoneal (VP) shunt may be inserted. A burr hole is created to insert a proximal catheter into the ventricle. The catheter is then connected to a valve and a distal catheter which drains CSF into the peritoneum using a long flexible shunt passer. The valve is used for pressure control (low, medium, high) – programmable valves available. Revision of shunts are common in children as they ‘outgrow’ their shunts. Revisions may also be required for infection, blocked shunts, etc. **AS WITH ALL IMPLANTS IN SURGERY, STERILE TECHNIQUE IS OF UTMOST IMPORTANCE TO PREVENT INFECTION* Module 21: Neurosurgery  Stereotactic Procedures The goal of stereotactic brain surgery is to locate a target within the brain by way of a predefined minimally invasive trajectory. This is accomplished using radiographic modalities (CT/MRI) to navigate three dimensionally and locate/destroy or biopsy the target structure by inserting a needle into the brain. The most common indications for stereotactic brain surgery are: Biopsy of tumour Deep brain stimulation for movement disorders ie. Parkinson’s Disease Transphenoidal Hypophysectomies – Surgical procedure used to treat endocrine pituitary disorders (pituitary tumours) and non-pituitary disorders. With the assistance of image guidance, the procedure is done transnasally with an endoscope with access though the sphenoid sinus into the pituitary fossa. Pituitary tumours are usually benign and involve endocrine disorders and are often found on routine eye exams as the pituitary gland is in close proximity to the optic chiasm. Symptoms often include double vision. Cranioplasty – Performed for repair of a skull defect resulting from trauma, malformation, or a surgical procedure, such as: when the skull bone flap cannot be replaced due to trauma to the skull, brain swelling & cannot replace flap, tumour eroded through the skull, or skull flap accidently dropped on the floor during surgery. A defect in the cranium is replaced with artificial substance/materials, such as titanium mesh or bone cement. Module 21: Neurosurgery