1. Procedures Craniotomy Review
Conditions That Can Require Brain Surgery /Craniotomy Brain surgery is performed to correct a variety of neurological disorders, or conditions. This information focuses on different conditions that may require brain surgery- brain tumors, acoustic neuromas, aneurysms and arteriovenous malformations.
Because the brain fits so compactly within the skull, an increase in tissue size caused by any kind of tumor (benign or malignant) can result in increased pressure within the skull. This condition, known as increased intracranial pressure, usually requires surgery to be corrected.
Q C 15 What is increased ICP? How is it monitored? Normal Intracranial pressure (adult) ranges from mm Hg. To measure: a catheter is placed in the ventricle, then either a manometer is used to manually measure the pressure, or the catheter is hooked up to a transducer and a machine that will provide a digital readout of the measurement.
Craniotomy Review

2. A & P Review STST Review (highly recommended) Questions for study:
What is the outermost layer of the meninges?
What is a shallow groove on the brain?
What is corpus callosum?
A layer of dura mater which separates the cerebral hemispheres is ___?
What is a deep groove in the brain called? ___________
The area that coordinates complex muscular movements associated with speech is?
The left hemisphere usually associated with what cognitive task?
What is the nondominant hemisphere usually associated with?
What are masses of gray matter which are located deep within the cerebral hemispheres called?
Which brain structure serves as a relay station for sensory impulses by channeling them to appropriate regions of the cortex for interpretation?
What are the structures called which are within the ventricles and produce CSF?
Which visceral activties does the medulla oblongata control?
Where is most CSF located?
The aqueduct of Sylvius connects the ____ and the ____ ventricles

3. A & P Review
What is the structure that extends from the level of the foramen magnum to the pons?
Which structure plays a key role in maintaining homeostasis by regulating a variety of visceral activities?
Which structure makes rapid and complex muscular movements possible?
The cerebellar hemispheres are connected in the midline by what structure?
What do neuroglial cells do?
Which cranial nerve is the largest, with several branches?
Which nerve supplies the muscles that act in adjusting the amount of light that enters the eyes?
Which nerve has autonomic motor fibers that supply the heart and smooth muscles?

4. Craniocerebral Trauma
L & B p –1374: T raumatic Brain Injury (TBI) (think back to Dr Ogletree’s talk and put this together)– is the leading cause of death and disability in the US. A TBI can be classified as penetrating (open) head injury (knife, bullet, baseball bat) or closed head injury (blunt injury to brain does that does not result in open skull fracture). The major cause of TBI is MVA (motor vehicle accidents).
The damage done following craniocerebral injuries is related to how the injury occurs, the nature of the injury, and the location of it. Types of injuires: acceleration injury (head hits moving object), deceleration injury (head hits stationary object, acceleration-deceleration injury (coup-countercoup phenomenon) –head hits object and brain “rebounds” within the skull.---2 or more areas of the brain can be injured. Deformation injuries –the force deforms and disrupts the integrity of the impacted body part (eg skull fracture).
Brain injury can result either from the direct effects of the trauma on the tissue, or from secondary responses: cerebral edema, hematoma, swelling, or increased ICP.
Skull fractures: intracranial trauma often occurs; the force of impact greatly increases the risk of underlying hematoma formation. The disruption of the skull can cause cranial nerve injury, allow bacteria to enter, or allow CSF to leak out. What is the difference between and open and closed skull fracture?
Open: Dura is torn; Closed: dura is not torn.

5. Types of Skull Fractures
Linear
Simple, clean break; low velocity injuries
Comminuted
Bone crushed to small, fragmented pieces; high-impact injuries
Depressed
Inward depression of bone fragments
Powerful blow; dura may or may not be intact
Basilar
Base of skull
May be linear, comminuted, or depressed
L & B p. 1373
Linear fractures are the most common—80% of all fractures. Typically extend from the point of impact toward base of skull. Dura usually remains intact, so CSF leak is not typical. However, subdural or epidural hematomas frequently undelrie the fracture. A hematoma places pressure on the brain tissue, increasing 1. Intracranial pressure 2. Risk of brain damage
Comminuted or Depressed: increase the risk of direct damage to brain from bruising (contusion) and bone fragments.
Basilar: may occur independently, but usually an extension of adjacent fractures; usually uncomplicated, but may nvolve frontal sinuses or petrous portion of temporal bone (middle ear).
Manifestation of CSF leakage: rhinorrhea (CSF via the nose) or otorrhea (CSF leak from the ear). Basilar fractures are difficult to see on x-ray, but have common manifestations: blood visible behind tympanic membrane (hemotympanum) or ecchymosis over mastoid process (Battle’s sign), or Bilateral periorbital ecchymosis (“raccoon eyes”). If CSF leakage is present, risk of infection is HIGH. Other complications of basilar skull fractures: injury to internal carotid artery and compression of cranial nerve II, VI, VII.

6. Pathophysiology: Hematoma
Accumulation of blood in the subdural or epidural space
Epidural vs Subdural
Q: B5: What is the difference between a subdural hematoma and an epidural hematoma? Main difference is location. A subdural hematoma forms between the dura and arachnoid and is usually caused by lacerations of venous structures. An epidural hematoma forms between the skull and the dura and is usually caused by laceration of the middle meningeal artery or one of its branches. It often occurs because of a fractured skull.
Q: B15: List and describe the three types of subdural hematoma
Acute: pt usually unconscious: massive venous bleeding leads to immediate formation of a large hematoma
Subacute: pt appears fine initially but deteriorates neurologically (lethargy, confusion, etc. ) over a period of several days to several weeks
Chronic: small initial hematoma is not diagnosed, the lesion gradually enlarges and encapsulates: pt may suffer headaches, confusion, and drowsiness or other neural deficits, such as aphasia or ataxia

7. Three types of hematomas: epidural, subdural, intracerebral
L & B p. 1375, p. 1376
Epidural: Occurs in space between the dura and skull, which normally adheres to one another. As the blood collects, the expanding hematoma strips dura away from the skull. Happens more frequently with young to middle age adults—with aging, the dura becomes more tightly attached to the skull.
Epidural hematomas usually result from a skull fracture ( often a blow to the head), resulting in a torn artery (often middle meningeal artery). Common site: temporal bone. They develop rapidly, as they originate from arteries—therefore, timely intervention is VITAL—to prevent large increase in ICP and herniation. With initial injury, the pt loses consciousness, then a brief lucid period before he declines from drowsiness to coma as the hematoma expands –stripping dura away from skull and placing pressure on brain tissue.
Subdural: localized mass of blood collects between dura mater and arachnoid mater—more common than epidural hematomas. Different in that they —often venous in origin, though may involve some small arteries. They usually develop within 48 hrs of initial head injury—but may not become apparent until up to 2 weeks after causitive injury. Pt may have a lucid period, but then develops drowsiness, confusion, enlargement of ipsilateral pupil within minutes or hours of the injury. Pt may c/o of unilateral headache. Hemiparesis and respiratory pattern changes may occur.
See Fig Alexander’s p. 969
Intracerebral : associated with contusions (bruise of the surface of the brain, typically associated with small, diffuse venous hemorrhages). Occur most frequently near bony prominences of the skull—cerebral edema results with increased ICP at peak hrs after injury.

8. Management of ICP: Possible locations of burr holes
Burr Hole: a hole made in the skull with a special drill. The hole may facilitate the evacuation of an extracerebral clot, or a series of holes may be made in preparation for a craniotomy.
L & B p. 1378:
Treatment of choice for epidural hematomas and large acute subdural hematomas is surgical evacuation of the clot. This can be performed via burr holes made into the skull. For epidural hematomas, the bleeding vessel is also ligated. A craniotomy is required to evacuate chronic subdural hematomas because the hematoma tends to solidify, making it difficult or impossible to remove through burr holes. Surgery is less successful in Tx of intracerebral hematomas because of widespread tissue damage.

9. Craniotomy: portion of skull and overlying scalp is removed to allow access to brain
Craniotomy: A surgical opening into the cranial cavity; a series of burr holes are made. The bone between the holes is then cut with a special saw called a craniotome. The tumor is excised, and the bone flap is turned down. A craniotomy may also be performed to repair defects associated with traumatic head injuries or to repair a cerebral anuerysm.
Classification above or below the tentorium:
Supratentorial: provides access to frontal, temporal, parietal, and occipital lobes. Incision is usually within the hairline over the area involved.
Infratentorial: access to lesions in the cerebellum or brainstem. Incision made a nape of neck, around the occipital lobe.
C10: List two methods by which the bone flap is secured to the cranium following a craniotomy: 1. Wire 2. Suture Plate and screw fixation

10. Pathophysiology: Tumor
See Table 24-2
Symptoms are caused by:
Compression of cranial nerves
Destruction of brain tissue
Irritation of cerebral cortex
Increased ICP
L & B p STST p. 980
Brain tumors are growths within the cranium, including tumors in the brain tissue, meninges, pituitary gland, or blood vessels. They may be benign or malignant, primary or metastatic, and intracerebral or extracerebral. Regardless of the type or location, they are potentially lethal because they grow within a closed cranial vault and displace or impinge cranial structures. So the use of “Benign” may be misleading—a tumor that is benign by histologic exam but is surgically inacessible may continue to expand, increasing ICP and causing neurologic deficits, herniation, and death.
See p. 980: Symptoms experienced by most intracranial patients r/t cranial nerves: Compression, Destruction, Irritation, Increased ICP

11. Pathophysiology: Tumor
Symptoms of a brain tumor can include dull, persistent headache; nausea or vomiting, problems with vision weakness: and seizures.
A glioblastoma is a tumor that is an irregular shape with 'tendrils' that grow into the surrounding area of healthy tissue, but are difficult to see fully since the cancerous growth can appear very much like normal tissue. The fact that this type of tumor is not a solid round tumor with definitive edges, makes it just about impossible to remove completely. This also means, unfortunately, that because it cannot be completely removed without severe damage to surrounding healthy tissue, there is cancerous tissue left which continues to spread and grow. This of course, can be slowed through the use of radiology and chemotherapy.
Multiforme simply means that the cancerous cells of the tumor are at different levels of disease. 'Multi' meaning 'many' and 'forme' meaning 'form' or 'shape'.
STST p. 979
Question B12: Glioma (Glibastoma) accounts for 40% of primary brain tumors.
Primary neoplasms arise from neural tissues or the meninges—cells & structures within the brain. They rarely metastasize beyond outside the CNS. Whereas secondary tumors (metstatic)—originate from structures outside the brain (breasts, lungs, prostate gland).

12. Pathophysiology: Acoustic Neuroma
B13: What symptoms are associated with acoustic neuroma? Which nerve is affected?
Symptoms of acoustic neuroma include loss of hearing, headache, vertigo, and facial pain. Acoustic neuroma involves the vestibularcochlear (auditory, acoustic, eighth ) cranial nerve.
Acoustic neuromas are tumors of the balance nerves occasionally they arise from the hearing nerve.  They are also called vestibular schwannomas.
It is thought to be caused by an error that occurs in one of the genes. There is a hereditary form of the disease called neurofibromatosis type II, in which patients develop tumors on both sides. Anatomy: The hearing nerve travels right next to the two balance nerves and the facial nerve (the nerve that controls the movement of the face). The tumors of the hearing or balance nerves generally start at the area where the nerves enter the temporal bone (bone surrounding the ear) and grow towards the brainstem. This area is called the cerebellopontine angle (the angle between the cerebellum and the brainstem).
Patients most commonly present with a one-sided or asymmetric hearing loss. Other common presenting symptoms include, one-sided tinnitus (ringing in the ear), balance problems, facial numbness. Sudden hearing loss is another presenting symptom of acoustic neuromas.
C6: It is important to restrict movement in and around the sterile field at all times, but why is this especially true during procedures near the cerebellopontine angle?
Restriction is always important to keep microbial contamination to an absolute minimum. However, the cerebellopontine angle is an area rich with cranial nerves, and surgical procedures in this area are especially dangerous to the patient because of the number of nerves and vessels, and the pontine respiratory center. The STSR could be positioned to easily pass instruments without disturbing the microscope or any other equipment. Remember the microscope stand and Mayfield pin-fixation devices are not foot/arm rests!

13. Pathophysiology: Aneurysm
The brain is supplied with blood through an extensive network of blood vessels. The vessels that carry blood from the heart to the brain are called arteries. The blood carried by these arteries is under pressure, in order to travel up to the brain and circulate throughout the brain tissue. A small weakening or tear in the inner lining of an artery can result in the formation of an aneurysm - a small, blood-filled, balloon-like stretching of the artery.
If the aneurysm is large enough, it can cause symptoms such as headache or visual problems. Aneurysms, like balloons, can burst. If an aneurysm bursts, blood will leave the artery under pressure and surround the brain tissue. This condition is known as an aneurysm bleed. Symptoms of an aneurysm bleed can range from a sudden, severe headache, to life-threatening coma.
The goal is to isolate the aneurysm from the parent vessel by placing a specially designed clip across the neck of the aneurysm.
Q: C5: List 3 options for treatment of a cerebral aneurysm
The aneurysm may be clipped
The feeding vessels may be clipped or ligated
The defect may be reinforced with synthetic materials (methyl methacrylate or mesh)

14. Aneurysm Treatment: STST Procedure 24-2
Procedural Steps:
1. Enter cranium as for craniotomy (Procedure 24-1)
These pics come from Neurosurgical Medical Clinic, Inc. and show options for treatment. ww.sd-neurosurgeon.com/diseases/aneurysms.html
1. The top pic shows how metal clip is applied to exclude the aneurysm from circulation. This required microscopic craniotomy and very skilled surgeon.
Outcome is heavily influenced by condition of the pt immediately prior to surgery. Considered “gold standard”
2. The next is the Hunterian Ligation—ligation of the feeding vessel reduces blood flow to the aneurysm sac. Approach favored in some high risk situations. This technique avoids craniotomy in that feeding vessels can be occluded at pt’s neck. Less likely to cure aneurysm—rebleeding can recur, as the aneurysm can fill by back filling from distal blood vessels.
#3: Entrapment: variation of Hunterian: both the feeding vessel and distal arteries are clipped to fully isolate the aneurysm from circulation. Used for some giant and fusiform aneurysms.
4. Endovascular Coil Occlusion: an Endovascular technique—placing a coil of thrombogenic wire inside the aneurysm to promote clotting of the fundus. Avoids an open operation. Incomplete occlusion or aneurysm recurrence happens in 5-20% in a month to years. Complications include stroke.

15. Aneurysm Repair
Sylvian fissure is split by bipolar cautery dissection of meningeal layers for separation of frontal and temporal lobes.
ETC.
See STST Procedure 24-2 p. 998
Alexanders p. 934 cites some important anatomy: The surfaces of the hemispheres form convolutions called gyri and intervening fissures called sulci. Two sulci of anatomic importance during surgery: 1. the central sulcus , or fissure of Rolando, which separates the motor from sensory cortex, and 2. the lateral sulcus, or fissure of Sylvius, which marks off the temporal lobe (Fig 23-7).

16. Pathophysiology: Arteriovenous Malformation
AVM: a congenital collection of abnormal vessels of the brain that increase in size with time.
Arteriovenous Malformations An arteriovenous malformations (AVM) in the brain is an abnormal collection blood vessels in the brain. This tangle of vessels forms long before birth and may begin to cause problems during childhood. As a person gets older, blood pressure increases and weakens the walls of the abnormal vessels. These changes may lead to bleeding. Symptoms of AVM can include headaches and, possibly, seizures.

17. Instruments, Equipment, Supplies
See
Q: What does a perforator do during a craniotomy? It helps to make bur holes.
Q: What type of suture would most likely be used to close the dura on an adult patient? 4-0 Neurolon
Q: What is papaverine used for during arterial intracranial surgery? Papavarine is used systematically or topically for its spasmolytic effect on smooth muscle. It is useful in all types of vascular procedures, not just intracranial.
Q: What is the ideal temperature for irrigation fluid that will be used intracranially? Normal body temperature—only occasionally will the individual patient situation require a cooler or warmer solution.
Q: What is a CUSA – how is it used? This acronym represents Cavitron Ultrasonic Aspirator. The CUSA fragments and emulsifies the tumor ultrasonically while irrigating and aspirating the debris. The high-frequency sound waves are able to fragment the tumor while avoiding nearby nerves and blood vessels. See Fig Alexanders

18. Craniotomy Instrumentation
STST Fig 24-19: Gigli Saw Handle , Guide, Blade
Fig 24-18: Hudson Brace with Attachments
As Jerry B said, you don’t see these used much these days, because electric or air driven power (drills and saws) save time and are so much more precise and convenient. But you should still be familiar, in case there is nothing else!

19. Craniotomy : What are these?
Fig 24-20: Penfield Dissectors a-e: Style # 1, Style # 2, Style # 3, Style # 4, Style # 5

20. ? Fig 24-21: Raney scalp clip system: Applicator and clip
Leroy Raney clips are used on scalp edges.
C2: How do Raney clips differ from aneurysm clips?
Raney clips: 1. Single use (disposable) external only 2. Typically plastic 3. Applied to the scalp 4. Several used for one patient 5. Inexpensive

21. ?
STST Fig 24-22: Microsurgical Instruments: Microsurgery Scissors, Jacobson microvascular needle holder , Rhoton micro forceps

22. ?
Fig 24-23: Aneurysm Clips: a. Temporary b. Permanent c. Applicator loaded with aneurysm clip
C2: How do Raney clips differ from aneurysm clips?
Aneurysm clips: 1. Single use—remain in the patient 2. Stainless steel, titanium 3. Applied at the aneurysm site 4. Generally, only one clip per patient 5. Expensive

23. Refer to AST Exemplar Handout
Procedural Steps
Refer to AST Exemplar Handout

24. Advanced Format Posterior Fossa Craniectomy
Procedures
Advanced Format
Posterior Fossa Craniectomy

25. Intermediate Format Cranioplasty Advanced Format: Craniectomy
Procedures
Intermediate Format
Cranioplasty
Advanced Format: Craniectomy
Neurosurgeons operate on the brain through openings in the skull.   When the operation is completed, large openings are closed, usually by replacing the bone that was originally there.   Small openings (less than 1cm or about 1/2 inch) are left open.  These smaller openings sometimes heal, but whether they do or do not, they generally do not cause a problem for the patient Sometimes a large opening cannot be repaired or covered during the initial operation.  Reasons for this include brain swelling, infection, and tumor.  In these patients, a skull defect persists.  Some patients choose to live with the defect, otheres get it fixed via—
Cranioplasty refers to reconstruction or reshaping of the skull, in this case to repair a defect. Cranioplasty can be performed using a number of techniques and materials, including bone grafts, metal plates, plastic, and mineral matrix materials.  Generally, the patient undergoes an operation using the old incision.  Once the incision is opened the skull is repaired, then the incision is closed. At Graduate Hospital, cranioplasty is performed using titanium mesh embedded in a polymethylmethacrylate matrix.  This is molded to the precise shape during the operation in order to achieve an optimal cosmetic result.  Polymethylmethacrylate is the same plastic marketed as Plexiglas(r) and Lucite(r), and is also used for "bullet-proof" glass (although we would never test it that way).  Advantages to this metal/plastic composite include speed of procedure, unlimited shaping, and achievement of full strength immediately.  Bone grafts and mineral matrices, in contrast, may require weeks or months before achieving their full strength.
STST p. 1012: The best material is the pt’ s own bone flap that has been preserved from previous procedure. Sometimes titanium plates and screws are used to secure the implant into the cranium. However, titanium plates are preformed and are not easily molded.

26. Objectives
Assess the related terminology and pathophysiology of the ________________.
Analyze the diagnostic interventions for a patient undergoing a craniectomy.
Plan the intraoperative course for a patient undergoing_____________.
Assemble supplies, equipment, and instrumentation needed for the procedure.

27. Objectives Choose the appropriate patient position
Identify the incision used for the procedure
Analyze the procedural steps for cranioplasty.
Describe the care of the specimen

28. Terms and Definitions See MAVCC Unit 11
STST Red and italicized or bolded terms

29. Definition/Purpose of Procedure
Craniectomy
Cranioplasty
L & B p. 1391
Craniectomy: excision of a portion of the skull and complete removal of the bone flap. This procedure may be done to provide decompression after cerebral edema. Pressure on brain structures is lessened by providing space for expansion. This method (not creating a bone flap, but removing the bone) is usually used for posterior fossa procedures, epidural or subdural hematoma removal, ventriculostomy, ICP monitor placement, or stereotactic cranial procedures. The bone that is removed is not replaced, and if the defect is large, cranioplasty may be performed.
Cranioplasty: Plastic repair to the skull in which synthetic material is inserted to replace the cranial bone that was removed. This procedure may be performed after a large craniectomy (or craniectomy). The plastic repair restores the contour and integrity of the cranium.

30. Anatomy
Best sources for Anatomy are your STST and Alexanders—it’s all there. Review and correlate with A & P class. See Alexanders pp
Surgery.uchicago.edu
Between the brain and the skull are the three coverings or membranes known as the dura, arachnoid and pia. These membranes provide additional support and protection for the brain. Within the brain are fluid-filled compartments called ventricles Cerebrospinal fluid (CSF) is produced it these ventricles and circulates around the entire brain and spinal cord to both provide nutrients to the brain and absorb shocks. The delicate tissues of the brain also need a constant supply of oxygen and glucose (blood sugar) to function properly. These necessary nutrients are supplied by a specialized network of blood vessels in the brain.

31. Physiology Cerebrum Cerebellum Brain stem (Medulla)
The brain can be separated into several different areas each with a very specific set of functions. The cerebrum, the largest part of the brain, is further separated into two halves known as the left and right hemispheres. The cerebrum controls movements and sensation, speed, thoughts and behaviors. The cerebellum, located in the back of the brain, regulates balance and coordination. The brain stem, which sits just below the cerebrum and the cerebellum, maintains such vita1 functions as breathing and blood pressure. Although smaller in size, its functions arc essential for life.
Don’t forget the cranial nerves Table p. 978 and Fig 24-11

32. Pathophysiology See prior slide: Acoustic Neuroma
Craniectomy also performed for:
Posterior Fossa Procedures, epidural or subdural removal, ventriculostomy, ICP Placement, or stereotactic cranial procedures
STST pp Alexanders p. 943
Tumors to the 8th cranial nerve (acoustic or vestibularchochlear) are dangerous because they are close to the cranial nerves and the brain stem. As they grow and compress these structures, there is loss of normal nervous function. The acoustic nerve has 2 parts: the cochlear for hearing and the vestibular for balance. An acoustic neuroma is a benign growth growing from the nerve sheath as it enters into the internal auditory meatus. It arises deep in the angle between the cerebellum and the pons. (Remember previous information about cerebellopontine angle). Symptoms may include unilateral deafness, tinnitus, unilateral impairment of cerebellar function, numbness of the face from involvement of the 5th cranial nerve—and papilledema caused by increased ICP. (What is papilledema? Edema and inflammation of the optic nerve at its point of entrance into the retina. It is caused by increased ICP, often due to a tumor of the brain pressing on the optic nerve. Blindness may result unless relieved).

33. Surgical Intervention: Special Considerations
Patient Factors
Hair removal and handling
Room Set-up
Depending on position of patient, must strategically place all equipment
EMG, ESU units (mono and Bipolar, Headlights, microscope &/or loupes, CUSA, laser if used, 2 suctions, Mayfield table if used
Anesthesia: General
C4: What supplies may be necessary to remove scalp hair in the OR?
Clippers (battery or electric) 2. Bag for hair 3. Small basin with water
4. Soap solution 5. safety razor
Save hair in plastic bag—label

34. Surgical Intervention: Positioning & Prepping
Position during procedure
Depends on tumor location
May be prone or semi-Fowler’s
Supplies and equipment
3-pt fixation device often used
(Gardner-Wells or Mayfield)
pillows, pads, sheets, blankets, wide tape,
Chest or axillary rolls
Special considerations: high risk areas
Depends on position: bony prominences, axilla, genitals, eyes
Prep: protect eyes and ears from prep solution
Once circulator scrubs, neurosurgeon often paints with iodophor and alcohol

35. Surgical Intervention: Special Considerations/Incision
X-rays in room at start
Saline at room temp
Close monitor of amt irrigation used
State/Describe incision
STST p. 1003
X-rays include: CT, MRI, arteriograms, plain film studies
Steriods are started 48 hrs prior to reduce cerebral edema, and IV antibiotics at the start of the procedure
Urinary catheterization before positioning
After catheterization, mg of Lasix (furosemide) is given IV. After dural exposure, IV Mannitol is infused.
The incision is made 2 cm medially to the mastoid process ; suboccipital muscles and fascia are incised w/electrocautery, and stripped away from bone w/periosteal elevator—another description: incision is made from mastoid tip to mastoid tip, in an arch curving upward 2 cm above the external occipital protuberance

36. Surgical Intervention: Supplies
General: basic pk, craniotomy pack or drape, basin set, gowns & gloves, dressing materials, medications, suction x 2, asepto, ESU pencil for monopolar, raytex & laparotomy sponges
Specific
Drapes: square drape w/towels that may be sutured in place w/silk on cutter; craniotomy drape w/adhesive fenestration
Suture & Blades
#10, #11, #15
4-0 silk and 4-0 neurolon
Medications on field :
Meds: antibiotic irrigation; hemostatic agents (Gelfoam w/topical thrombin, Surgicel, Avitene)
C9: List two materials that can be implanted during cranioplasty and that can be molded to fit the cranial defect Methyl methacrylate 2. Stainless steel mesh

37. Surgical Intervention: Supplies
Catheters & Drains: Hemovac; Foley cath
Nerve stimulator for ID 7th cranial nerve
Control syringe & hypodermic needles
Bipolar cord to attach to Bayonet forceps
Cottonoids of various sizes
Raney scalp clips
MRI compatible hemostatic clips
Telfa, cotton balls
Ultrasound wand drape

38. Surgical Intervention: Instruments
General
Specific
Basic Neuro or craniotomy
Microsurgical (available)
Anspach or Midas Rex power instruments w/attachments or cranial perforator & craniotome
If no Anspach or Midas Rex, air drill w/bits and burrs
Alexanders Ch 23 has many good pics of neuro instruments
See Fig 2-33 p. 965 for Midas Rex, Anspach drill Fig for Air drill (Surgairtome) and Fig for CUSA machine
Types of restractors p. 954 Fig 23-44
Figures on p. 977 show types of Bayonet Forceps and Microsurgical instruments

39. Surgical Intervention: Equipment
General
Specific
EMG, ESU units (mono and Bipolar, Headlights, microscope &/or loupes, CUSA, laser if used, 2 suctions, Mayfield table if used

40. Surgical Intervention: Procedure Steps
Follow steps 24-1 for entry into cranium
See Procedure 24-3
Alexanders p is Suboccipital Craniectomy for Posterior Fossa Exploration
STST p. 1004
Once the incision is made (previously described) and the cranium is entered (See Procedure 24-1 for entry of cranium)—a bone flap over the lateral 2/3 of cerebellar hemisphere is turned (or bur holes made) and dura is exposed. Additional bone is removed w/double action rongeur and Kerrison rongeur to expose transverse sinus
* Have available large Kerrison and Adson, Leksell, or Stille-Leur Rongeurs for removal of thick bone
The dura is opened and retracted w/sutures. The cerebellum is elevated and arachnoid opened to allow for continuous CSF drainage.
* Brain spoons and self-retaining retractor should be prepared and microscope draped
After self-retaining brain spoon retractors are placed, the microscope is positioned. Bone removal with air powered drill exposes internal auditory canal. * Air drill should be loaded w/selected bur, hooked to source, and tested before use
Surgeon assesses relationship of tumor to the cochlear and vestibular nerves. It is carefully rotated and 7th cranial nerve is identified
*Have nerve stimulator ready. If using CUSA, it should be ready to go, with sterile handpiece attached.

41. Surgical Intervention: Procedure Steps
After location of these nerves is identified, internal decompression of the tumor is accomplished w/ultrasonic aspirator, bipolar coagulation, and sharp dissection.
* OR may be darkened to enhance surgeon’s view via microscope. Remain alert—this is the long and tedious part.
Once tumor is removed, hemostasis is evaluated and dura closed. Graft may be performed using pericranial tissue.
* Ask about care of specimen. Irrigation at body temp will be needed. Prepare for closure
Bone flap is replaced and secured and muscle and fascia are closed. Skin is closed w/nylon suture or stainless steel staples
From here – Follow closure steps listed in STST Procedure 24-1.
Pics above: C: Retractors are positioned and bone is removed w/rongeur D: Dura is opened and retracted, exposing the cerebellar hemispheres.
See also Alexanders p. 982 Fig

42. Counts Initial: Sponges, sharps First closing Final closing Sponges
Counting all the cottonoids can be time consuming. Keeping them organized on the field can be a challenge. Learn to organize using manufacturers cardboard or over turned over emesis basin. When a full pack is used, you may count with your circulator and pass off the field and the circulator will contain and maintain until end of case and counts are complete.

43. Specimen & Care
Identified as acoustic neuroma or as informed by surgeon
Handled: usually routine

44. Immediate Post op Remain sterile until the patient is safely out of OR
Managing the head while removing pin fixation device takes much skill and care (not to drop!)—usually surgeon or anesthesia takes this on
Multiple lines can be easily displaced upon transfer—extreme caution!

45. Postoperative Complications & Recovery
General: (Neurological Deficits/S & S)
Increasing drowsiness or sleepiness, Increasing weakness
Visual problems
Persistent, severe headache
Fever
Vomiting
Seizures or abnormal movements
Redness, swelling or drainage of fluid around the incision
Specific
Hearing loss and facial hemiparesis from damage to 7th and 8th cranial nerves are most common
Wound infection, meningitis
Subdural or Epidural hematoma or Intracerebral hemorrhage
These symptoms may indicate a developing complication. The patient should be informed to report these upon hospital discharge (7-10 days postop).

46. What are stereotactic procedures?
Technique used for precise localization of intercranial masses using CAT and MRI using three-dimensional navigation system
MAVCC OBJ 9 STST p Alexander’s p. 987 Procedure
Cranial surgeries which allow for accurate placement of a probe, needle, or electrode into a specific location in the brain in order to treat, biopsy, or destroy tissue in the target area. It allows surgeons to reach areas that were previously too small or inaccessible. Endoscopes and lasers may also be used with stereotaxic equipment.
It uses CT, MRI, &/or PET (positron emission tomography) scans, in conjunction with x-rays and computer technology, to identify the 3-axes coordinates of the target area.
The primary focus of this technique has been biospy of hard-to-reach intracranial tumors---but it is also being used for treatment of movement disorders such as Parkinson’s Disease. Other than tumors, common target areas include the basal ganglia, thalamus, hypophysis, aneurysms, and anteriolateral spinal tracts. Target areas undergo biopsy or are destroyed by chemical or mechanical means or electrically stimulated to control intractable pain. Also electrodes may be placed to various regions to determine site of origin for seizures.
Equipment traditionally used includes a rigid halo head-mounted frame to provide a marker system during computer imaging and a rigid platform for mounting instruments on during surgery.

47. What is a Gamma Knife? What is a Gamma Knife?
Memphis Regional Gamma Knife Center uses the Leksell Gamma Knife®, which is actually not a knife. It’s a revolutionary tool that allows neurosurgeons to operate on brain tumors, lesions, arteriovenous malformations, trigeminal neuralgia and other specific indications of the brain without making a single incision. The Gamma Knife utilizes a single dose of radiation directed through the 201 ports of a collimator helmet to specific targets within the brain. Unlike conventional radiation therapy, the Gamma Knife is so exact it damages and destroys abnormal tissue while leaving the adjacent normal tissue intact.
The Gamma Knife has no moving parts during treatment, which provides enhanced safety, accuracy, reliability and reproducibility. Because of its accuracy, the Gamma Knife allows doctors to treat tumors previously thought inoperable, including tumors near the brainstem, cranial nerves and optic apparatus. Generally, patients are treated and released within 24 hours.
As with any radiation treatment, Gamma Knife results are not immediate. The treatment initially stops the growth of brain tumors and lesions, and their size should decrease over time.

48. Resources STST pp. 966-974; 979-984. Procedure 24-1; 24-3
AST Exemplar: Craniotomy-Tumor Excision
Lemone & Burke pp ;
MAVCC Module Unit 11
Alexander’s Ch 23

49. Questions
C9: List two materials that can be implanted during cranioplasty and that can be molded to fit the cranial defect.
C10: List two methods by which the bone flap is secured to the cranium following a craniotomy.
C8: Name two approaches that can be used for surgery of the pituitary.
a.. Craniotomy b. Transphenoidal
C9: a. Methylmethacrylate b. Stainless steel mesh
C10: a. Wire b. Suture c. pate and screw fixation