Far-lateral approach for lower basilar artery aneurysms.

OBJECTIVES: Aneurysms of the lower basilar artery are surgically difficult to expose and clip. Various cranial base approaches, which are associated with significant morbidity, have been used to access this region. We have used the far-lateral approach without occipital condyle drilling for clipping of lower basilar junction aneurysms to assess the exposure for adequate visualization and clipping, and to study the complications and outcome. DESIGN: Retrospective review of data. SETTING: Between 1997 and 2001, four patients with lower basilar artery aneurysms were operated on at Louisiana State University Health Sciences Center in Shreveport. The far-lateral approach without drilling of the occipital condyle was used in each procedure. PARTICIPANTS: Cases of basilar artery aneurysms. MAIN OUTCOME MEASURES: Glasgow Outcome Scale (GOS) score. RESULTS: All four aneurysms were clipped successfully. All patients had good outcome (GOS scores of 5 and 4). There were no instances of cerebrospinal fluid leakage or pseudomeningocele. Two patients experienced transient morbidity in the form of voice hoarseness and swallowing difficulty. CONCLUSION: The far-lateral approach without drilling of the occipital condyle adequately exposed the lower basilar artery for successful clipping of aneurysms and was associated with minimal morbidity.

Ventriculosubgaleal shunts for posthemorrhagic hydrocephalus in premature infants.

OBJECTIVE: The early management of posthemorrhagic hydrocephalus in premature infants is challenging and controversial. These infants need a temporary cerebrospinal fluid (CSF) diversion procedure until they gain adequate weight, and the blood and protein levels in CSF are reasonably low before permanent shunt can be placed. Various options are available with their associated advantages and disadvantages. Ventriculosubgaleal shunts have been recommended as a more physiologic and less invasive means of achieving this goal. We have performed this procedure in 6 premature infants to evaluate their effectiveness and complications. METHODS: Six consecutive premature infants with posthemorrhagic hydrocephalus underwent placement of ventriculosubgaleal shunts over a 1-year period of time. We reviewed their clinical and imaging progress to assess the ability of the shunt to control hydrocephalus and the complication rates. RESULTS: In all 6 patients, the ventriculosubgaleal shunt controlled the progression of hydrocephalus as assessed by clinical and imaging parameters. A permanent shunt was avoided in 1 patient (16.6%). However, 4 patients developed shunt infections, 1 involving the ventriculosubgaleal shunt itself, and 3 immediately after conversion to ventriculoperitoneal shunt. The total infection rate of the series was 66.6%. All infections were caused by staphylococcus species. There was only a 1% shunt infection rate in our institution for all nonventriculosubgaleal shunts during the same period of time. CONCLUSION: Placement of ventriculosubgaleal shunts for interim CSF diversion in neonates with posthemorrhagic hydrocephalus is effective as a temporary method of CSF diversion. However, our experience has shown that it is associated with a unacceptably high CSF infection rate. A potential cause for infection is CSF stasis just beneath the extremely thin skin of the premature infants, promoting colonization by skin flora. CSF sampling before conversion to a permanent shunt and replacement of the proximal hardware, which has been in situ for a prolonged period, may decrease the infection rates. At present, the procedure is no longer performed at our institution.

Complications of bioresorbable fixation systems in pediatric neurosurgery.

OBJECTIVE: Bioresorbable devices are an attractive alternative to metal instrumentation for internal fixation of bone, and have been used extensively in orthopedic and craniofacial surgery. In neurosurgery, the reported literature is predominantly confined to pediatric craniofacial procedures, with encouraging results and minimal complications. We have used bioreabsorbable plates and screws in cranial and spinal pediatric neurosurgery procedures. We report four complications related to their usage. MATERIALS AND METHODS: Bioabsorbable instrumentation was used in pediatric patients for fixation of bone after cranial or spinal procedures. RESULTS: Four patients developed complications related to the instrumentation: 2 following cranial surgery for epilepsy, 1 after correction of a growing skull fracture, and 1 after laminotomy for an intramedullary tumor. Two patients had fibrous encapsulation with granuloma formation and 2 patients had osteolysis following the fixation. CONCLUSION: Bioabsorbable fixation devices for the stabilization of bone following craniotomy and laminotomy in pediatric patients may be associated with complications, including granuloma formation and osteolysis.

Pathophysiological changes in cerebrovascular distensibility in patients undergoing chronic shunt therapy.

OBJECT: Patients undergoing long-term shunt therapy following shunt malfunction often present with acute neurological deterioration, high intracranial pressure (ICP), and yet small or slit ventricles. It is believed that low brain compliance prevents ventricle enlargement in such cases. To elucidate the underlying pathophysiology, the authors estimated compliance as a function of cerebrovascular distensibility in 45 patients undergoing chronic shunt therapy. METHODS: The ICP and pressure-volume index (PVI) were measured at end-tidal CO2 of 30 mm Hg (PVI30) and 40 mm Hg (PVI40). The ventricle volume was dichotomized as slit/small/normal or dilated based on the frontooccipital horn ratio. In 18 patients PVI30 was normal (18.4 +/- 4 ml), whereas in 27 patients it was significantly elevated (45.5 +/- 14 ml). Clinical symptoms or ventricle size at presentation did not correlate with the PVI30. The ICP and PVI at end-tidal CO2 of 40 mm Hg were significantly higher than those at end-tidal CO2 of 30 mm Hg (p < 0.001 and < 0.02, respectively) suggesting an increased cerebrovascular distensibility. CONCLUSIONS: The authors did not observe a low compliance in patients undergoing chronic shunt therapy who, at shunt malfunction, presented with a slit/small/normal ventricle; however, analysis of the findings strongly indicated that an increased cerebrovascular distensibility was present in these patients. This may explain the high ICP and acute clinical deterioration following shunt malfunction in such cases.