The Massachusetts General Hospital Handbook of Neurology

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Adult Neurology > Neurosurgical Procedures

Neurosurgical Procedures

A. See also

Trauma, p. 119; Intracranial Hemorrhage, p. 61; Intracranial Pressure, p. 67; Spinal Cord, p. 113; Tumors of Brain, p. 120; PEDIATRIC Tumors, p. 151; PEDIATRIC Head Circumference, p. 137.

B. Neurosurgery pre-op orders

• 1. NPO except meds after midnight: IV fluids (D5NS); NGT to suction if urgent case.

• 2. Compression boots on call to OR.

• 3. Void on call to OR.

• 4. Pre-op meds: Consider:

  • a. Steroids: E.g., dexamethasone 10 mg PO qhs, 10 mg IV on call. For pts on chronic steroids, give stress-dose steroids (see p. 173).

  • b. Prophylactic Abx: E.g., 1 g cefazolin or vancomycin on call.

  • c. GI prophylaxis: E.g., ranitidine 150 mg PO qhs, 50 mg IV on call to OR.

  • d. Seizure prophylaxis: Phenytoin 100 mg tid for craniotomy/ hemicraniectomy, large/superficial ICH/tumor resection, seizure on presentation, etc.

  • e. Sleeping pill: Beware of benzodiazepines in pts who are elderly or encephalopathic. Consider quetiapine.

C. Pre-op check

The pre-op note should document:

• 1. Vital signs and neuro exam.

• 2. Tests: Chem 10, CBC, platelets, PT, PTT, ACD levels, UA, EKG, CXR.

• 3. Blood: Type and hold 2 units (4 for vascular cases).

• 4. Pt consent.

• 5. Plan.

D. Post-op orders

• 1. Admit: To postanesthesia care unit, transfer to ICU when stable.

• 2. Vital signs: Every 15 min 4 h, then q1h; temperature q4h 3 d, then q8h; craniotomy checks.

• 3. Activity: Bedrest, HOB elevated 20-30 degrees for craniotomies. Compression boots or TED hose. Incentive spirometry q2h while awake (except if posttranssphenoidal).

• 4. Diet: NPO except meds.

• 5. I/Os: Hourly. If no bladder catheter, straight catheter q6h prn.

• 6. IV fluids: E.g., NS + 20 mEq KCl/L at 75 cc/h.

• 7. O₂: E.g., 2 L per nasal cannula.

• 8. Meds: Consider same options as pre-op; also BP meds, analgesic, and fever prophylaxis.

• 9. Postanesthesia rigors: Too soon for post-op infection. Meperidine or buspirone can help.

E. Post-op check

Document events, VS, I/Os, exam, wound check, labs, plan.

F. Post-op deterioration

• 1. Emergent CT for all altered mental status.

• 2. DDx: Hemorrhage, infarction, seizure, tension pneumocephalus, infection, cardiac or pulmonary event, persistent anesthetic effect (unlikely in a pt who was initially doing well post-op).

• 3. Seizures: Intubate pts who have labored breathing or do not quickly regain consciousness. Draw ACD levels and then bolus with additional ACDs; do not wait for levels.

P.85

G. Craniotomy

• 1. Frontal, temporal, parietal, and occipital craniotomies: For access to cortical and subcortical lesions; also for access to the ventricles. Transcallosal approaches have increased risk of venous infarction; usually require pre-operative angiogram.

• 2. Posterior fossa (suboccipital) craniotomy: Used to reach the cerebellopontine angle, one vertebral artery, or as an extreme lateral approach to the anterolateral brainstem. In addition to the routine post-op issues described above.

  • a. Closely monitor respirations: Pts may benefit from 24-48 h post-op intubation since posterior fossa complications often have respiratory arrest as the presenting sign.

  • b. Keep SBP <160: With nicardipine, labetalol, or nitroprusside if necessary. Sudden BP change suggests hematoma or edema.

  • c. Posterior fossa hematoma or edema: Presents with sudden changes in breathing or BP; pupils, consciousness, and ICP are not affected until late. Rx is rapid intubation, ventricular drainage (through prophylactically placed burr hole, if possible), and immediate reoperation. An emergent CT scan may be informative but may dangerously delay treatment.

  • d. Watch for CSF leak through wound or nose: see p. 20.

  • e. If corneal reflex is poor due to 5th or 7th nerve injury, protect eye with drops, ointment, or patch.

• 3. Pterional craniotomy: To reach anterior circulation and basilar tip aneurysms, cavernous sinus, and suprasellar tumors. The craniotomy is centered over the depression of the sphenoid ridge. When the sella is accessed, consider post-op complications of transsphenoidal surgery, below.

H. Transsphenoidal surgery

Used for sellar tumors without significant suprasellar extension.

• 1. Post-op complications: DM (see p. 199), adrenal insufficiency, hypothyroidism, hypogonadism, secondary empty sella syndrome (visual loss from chiasm retracting into sella), infection, CSF leak (p. 20), carotid artery rupture, nasal septal perforation.

• 2. Post-op orders:

  • a. I/Os q1h, with urine specific gravity q4h and electrolytes with osmolarity q6h.

  • b. IV fluids: D5 1/2 NS + 20 mEq KCl/L at 75-100 mL/h, plus replace urine output mL for mL.

  • c. Abx: Continue pre-op regimen until nasal packs removed.

  • d. Steroid taper: E.g., hydrocortisone 50 mg IM/IV/PO bid, taper 10 mg/dose/d. Test AM cortisol 24 h after stopping steroids.

  • e. Activity: No incentive spirometry or drinking through a straw, to avoid aspirating the sinus fat graft.

I. CSF access and decompression techniques

All increase risk of CNS infection.

• 1. External ventricular drain: AKA intraventricular catheter or ventriculostomy. For temporary ICP monitoring and CSF drainage. May be inserted at the bedside, if anterior approach. Usually done in nondominant hemisphere.

  P.86

  • a. Orders: Hang bag 15 cm above ear (EAM - external auditory meatus); drain for pressure >15 cm ( EVD @ 15 and open ). If need to withdraw more fluid, first lower the bag (e.g., to 10 cm). Empiric nafcillin 2 g IV q4h, cefazolin, or vancomycin.

  • b. Weaning: Can sometimes wean even if output is high (~150 cc qd). Clamp; open if pressure >20; then leave open until it decreases to 15. Pts. who do not tolerate clamping may need a shunt.

• 2. Ventricular shunts: Usually ventriculoperitoneal; occasionally ventriculoatrial, ventriculopleural, or lumboperitoneal. For permanent CSF drainage. Inserted in OR.

  • a. Hardware: May contain valves to prevent overshunting, reservoirs to allow CSF taps, or tumor filters to prevent seeding.

  • b. Complications: Infection, undershunting or occlusion, overshunting (can cause headache or SDH).

• 3. Shunt or reservoir tap: To access the reservoir, shave scalp, iodine prep for 5 min, and insert a 25-gauge butterfly needle at an oblique angle.

• 4. Ommaya reservoir: An indwelling reservoir attached to a ventricular catheter. It allows intrathecal chemotherapy or Abx, or recurrent CSF aspiration.

• 5. Lumbar drain: Temporary catheter placed to lower CSF pressure, usually to treat postoperative CSF leak or before VP shunt for presumed NPH. Pt should be on Abx while drain is in place.