Craniotomy

Trephination and craniotomy performed by abrasion, scraping, crosscut sawing, and drilling are the oldest known surgical techniques used by primitive peoples. Comparative osteology studies have demonstrated that using primitive stone or metal instruments, the Sirkaks (Inca surgeons) achieved an average survival rate of 50 to 70% of their craniectomy patients, with little incidence of infection or other complications.

Craniotomy has advanced markedly since these early period and a wide range of surgical approaches, indications and instrumentation are now available.

Craniotomy and ischaemic stroke

Craniotomy is sometimes indicated in patients with stroke. This, in ischaemic stroke patients may be to remove a cerebellar infarct if causing brain stem compression or to perform a focussed lobectomy for infarcted tissue causing severe raised intracranial pressure and imminent coning. One study compared the clinical course of 36 consecutive patients with severe acute ischaemic stroke (more than two thirds of the middle cerebral artery territory) treated with hemicraniectomy (CE; n=17) or moderate hypothermia (MH; n=19) in terms of intracranial pressure control, mortality, and specific treatment parameters. Mortality was 12% for CE and 47% for MH. Duration of mechanical ventilation and of neurological intensive care unit stay did not significantly differ, but duration of catecholamine application and maximal catecholamine dosage were significantly higher in the MH group.

In conclusion, in the study, for patients with severe ischaemic stroke, craniotomy results in lower mortality and lower complication rates compared with moderate hypothermia.

Craniotomy and haemorrhagic stroke

Craniotomy is also valuable in selected patients with haemorrhagic strokes such as an intracerebral haemorrhage and in patients with an aneurysmal subarachnoid haemorrhage with intracerebral haematoma. Supratentorial intracerebral hematomas in spontaneous ICH and in SAH cases are often evacuated in rapidly deteriorating patients.

Craniotomy for rapidly worsening patients with supratentorial intracerebral hemorrhage and radiologic signs of brain tissue shift may result in functional independence in approximately a quarter of patients. However, all comatose patients who lost upper brainstem reflexes and had extensor posturing died despite surgery. Therefore, surgery may prevent death but not necessarily disability. It is important to choose the patient carefuly and only offer operation to those who will benefit. Also critical is that surgery should be performed in a timely manner before irreversible damage occurs.

Some useful approaches and techniques

Hemicraniectomy
Hemicraniectomy has been reported by various authors and improves outcomes for some patients with ischaemic stroke (middle cerebral artery occlusion) and in some cases of ruptured brain aneurysms following surgery. Decompressive craniectomy has historically served as a salvage procedure to control intracranial pressure. It can be effective and must be done in a timely fashion before irreversible brain damage occurs.

Supraorbital craniotomy
The supraorbital approach is well accepted for lesions in the anterior fossa, the sellar region, and the anterior circle of Willis. Lesions in the interpeduncular fossa can also be effectively treated using a supraorbital approach, which can be ipsi- or contralateral to the side of the lesion, depending on the exact location of the lesion. The use of an endoscope is essential to visualize these lesions that lie in the shadow of the sellar and parasellar anatomic structures. The major advantage over other approaches are a nearly perpendicular surgical route. The cosmetic results of the eyebrow incisions for this approach were excellent in all patients.

The transorbital approach
The transorbital keyhole approach to anterior communicating artery aneurysms was developed as a minimally invasive method for safe control of the anterior communicating artery complex. This approach does not necessitate resection of the gyrus rectus. The transorbital keyhole approach provides more ventral access than the supraorbital approaches, and the anterior communicating artery complex can be controlled by splitting the basal aspect of the interhemispheric fissure. The orbitocranial keyhole approach seems to be substantially better than the craniotomy, although it requires additional effort and time.

Post-Craniotomy problems

Pain
The conventional wisdom that neurosurgical patients experience minimal postoperative pain and require little analgesia has been challenged. In one study results confirm that the average craniotomy patient has less postoperative pain than patients who undergo other surgical procedures, although patients who undergo frontal craniotomy may require more aggressive pain management.

Nausea and vomiting
Nausea and vomiting are frequent and protracted after supratentorial and infratentorial craniotomy. A prospective, randomized, placebo-controlled, double-blind study was designed to evaluate the efficacy of Ondansetron, a 5-HT3 antagonist, in preventing postoperative nausea and vomiting (PONV) after elective craniotomy in adult patients. Administration of single-dose Ondansetron (8 mg intravenously) at wound closure was partially effective in reducing acute nausea and vomiting but had little delayed benefit. Ondansetron is very effective for nausea and vomiting prophylaxis after fentanyl/isoflurane/relaxant anesthesia and infratentorial craniotomy. Reduced vomiting frequency was seen with Ondansetron at 4, 8, 12, and 24 hours (P < .05).

Infection
The incidence of postoperative infection following craniotomy is of the order of 10%. An 8.9%-postcraniotomy meningitis incidence was found in one study. Postcraniotomy meningitis resulted in a high mortality rate and a longer hospital stay, with repeat operation identified among the risk factors. Gram-negative bacilli were the most common etiologic agents isolated. Although several risk factors were identified by univariate analysis, including postoperative external ventricular shunt (OR = 2.92, CI 95% = 1.245-6.865, P =.014), remote site infection (OR = 2.85, CI 95% = 0.995-8.173, P =.051), and repeat operation (OR = 5.02, CI 95% = 1.569-16.066, P =.007), only repeat operation remained in the multivariate analysis model (OR = 3.68, CI 95% = 1.158-11.700, P =.027).

Created by B I Ogungbo in September 2002. Modified May 2009. ©