Faculty Bibliography

OBJECTIVE:Decompressive hemicraniectomy has been proposed as a potential treatment strategy in patients with poor-grade aneurysmal subarachnoid hemorrhage presenting with focal intracerebral hemorrhage causing significant mass effect. Although hemicraniectomy improves overall survival rates, the long-term quality of life (QoL) for survivors in this patient population has not been reported. METHODS:Using adjudicated outcome assessments, we compare long-term clinical outcomes and QoL between a group of patients with poor-grade aneurysmal subarachnoid hemorrhage receiving decompressive hemicraniectomy (n=12) and a control group of similar patients managed more conservatively (n=10). RESULTS:Patients receiving decompressive hemicraniectomy experienced a statistically insignificant decrease in short-term mortality compared with controls (25 versus 42%); however, long-term QoL in hemicraniectomy survivors was generally poor. Furthermore, hemicraniectomy patients did not experience an increase in mean quality-adjusted life years over control patients (2.31 versus 2.22 yr). CONCLUSION/CONCLUSIONS:Decompressive hemicraniectomy prolongs short-term survival in patients with poor-grade aneurysmal subarachnoid hemorrhage with associated intracerebral hemorrhage; however, this trend is not statistically significant, and the overall QoL experienced by survivors is poor. Decompressive hemicraniectomy may be indicated if performed early in a select subset of patients. On the basis of our preliminary data, large prospective studies to investigate this issue further may not be warranted.

OBJECTIVE:Proximal posteroinferior cerebellar artery (PICA) aneurysms are challenging to treat surgically, with high reported perioperative complication rates. We describe the perioperative course and long-term clinical outcomes obtained via a far lateral suboccipital approach in 20 consecutive proximal PICA aneurysms. METHODS:Data were collected prospectively on the first 20 proximal PICA aneurysms treated surgically by a single surgeon (ESC) between December 1997 and April 2003. All aneurysms were clipped via a far lateral approach. Patients with unruptured aneurysms were assessed at 3 and 12 months after surgery. For all subarachnoid hemorrhage patients, a battery of outcome tests was performed at 3- and 12-month intervals. Outcomes were then compared with those of a contemporaneously managed population of ruptured right-sided posterior communicating artery aneurysms. RESULTS:The far lateral suboccipital approach achieved adequate exposure in all cases. There were no intraoperative complications or intraoperative aneurysm ruptures. All patients with unruptured aneurysms were fully functional at long-term follow-up. At 3 months of follow-up, 93% of the subarachnoid hemorrhage patients achieved a Glasgow Outcome Scale score of 1 to 2. At 12 months of follow-up, 92% achieved a Glasgow Outcome Scale score of 1 to 2. Compared with the patients with a ruptured right-sided posterior communicating artery aneurysm, no difference could be found in quality of life or activities of daily living at either time point. CONCLUSION/CONCLUSIONS:The favorable outcomes and low postoperative morbidity in this subset of patients argues that clipping via this approach be considered a first-line therapeutic option. When performed in this manner, PICA aneurysm surgery seems to have no greater morbidity than right-sided posterior communicating artery aneurysm surgery.

Diffuse bilateral enlargement of the choroid plexus has long been appreciated as a cause of shunt-resistant hydrocephalus in infants, most often secondary to cerebrospinal fluid overproduction. Despite the fact that such lesions have interchangeably been termed 'villous hypertrophy' (VH) or 'bilateral choroid plexus papilloma' (CPP), little attention has been paid to the pathological distinctions that characterize these two entities. We present a case of presumed VH in a 2-week-old female presenting with cerebrospinal fluid production-dependent hydrocephalus that ultimately required bilateral surgical ablation of the choroid plexus. Although the preoperative radiological diagnosis was consistent with VH, postoperative histological analysis suggested bilateral CPP. The neoplastic nature of the lesion was confirmed by specific staining for the proliferation index, showing an MIB-1 labeling index of 4%, characteristic of papilloma. Routine imaging and histological grading of choroid plexus hypertrophy and papilloma have not provided a reliable means of predicting malignant behavior or recurrence after surgical resection. Moreover, none of the previously reported cases of VH in the literature have analyzed pathological specimens for cellular proliferative potential. Therefore, we review the literature on VH and bilateral CPP and discuss the diagnostic and possible prognostic implications of distinguishing these variants by utilizing the MIB-1 marker for the proliferation index.

Aggressive surgical resection continues to be the mainstay of current meningioma management, with advances in microsurgical techniques facilitating the safety and effectiveness of this approach. Complete surgical removal of meningiomas provides the optimal opportunity for long-term remission. Advances in skull base surgical approaches have greatly improved patient outcomes for tumors in precarious locations once thought to be inoperable. For tumors that recur or are unresectable, stereotactic radiosurgery and conformal fractionated radiation therapy can provide safe, palliative treatment with favorable long-term outcomes. Additionally, advances in the understanding of molecular biologic and biochemical mechanisms underlying meningioma growth offer unique opportunities for potential treatment adjuncts for atypical and malignant tumors. This review discusses current understanding of meningioma pathology and accepted meningioma treatment paradigms. The technologic advances and experimental strategies for the future treatment of complex intracranial meningiomas are also discussed.

There is renewed interest in primate models of acute stroke for the evaluation of potential therapeutic agents prior to clinical trials. The development of more precise functional outcome measures would improve the pre-clinical assessment of neuroprotective strategies. We have constructed a grading scale that utilizes an increased number of goal-oriented tasks to assess both behavior and motor function. The new scoring system is designed to enhance precision and accuracy when compared to existing scales. Twenty-seven male baboons were subjected to 1 h of middle cerebral artery territory occlusion followed by reperfusion. Outcome was evaluated using both a standard neurological function scale and a new task-oriented scale. Each scoring system was assessed for reproducibility (inter-observer reliability) and for association with radiographic infarct volume. The task-oriented grading system was significantly less variable than the standard outcome measure (p < 0.0001). The task-oriented neurological scale demonstrated stronger correlation with radiographic infarct volume (p < 0.0001) than the standard scale (p < 0.01) and more accurately reflected infarct size in animals with small strokes. Compared to the accepted system for grading neurological function, the task-oriented scale demonstrates improved inter-observer variability and a better association with radiographic outcome measures. Incorporating this refined neurological evaluation into a baboon model of stroke may serve to increase the functional predictive value of pre-clinical studies.

BACKGROUND:Although the development of significant interhemispheric intracranial pressure (ICP) gradients in the setting of unilateral stroke remains controversial, no study to date has investigated the existence of these gradients in a controlled, reproducible, clinically relevant model. Therefore, we used a primate model of reperfused hemispheric stroke to better characterize the development of these gradients. METHODS:Bilateral intraparenchymal ICP was continuously monitored in 7 adult male baboons subjected to left hemisphere reperfused stroke. Interhemispheric ICP gradients were calculated for each baboon and plotted over time. Infarct volume was determined using T2-weighted magnetic resonance imaging (MRI) at sacrifice. RESULTS:A bimodal distribution of interhemispheric ICP gradients was observed in animals with >20% infarct volume (22.1% +/- 0.9; range 21-23%) versus < or = 15% infarct volume (6.6% +/- 2.7; range 1-15%). In animals with >20% infarct volume, interhemispheric gradients developed early and persisted throughout the monitoring period. At 12 hours postreperfusion, animals with large infarcts demonstrated a mean pressure gradient of 13.8 +/- 4.3 mm Hg, compared to a mean gradient of -2.6 +/- 1.1 mm Hg for animals with < or =15% infarct volume. The difference in pressure gradients was statistically significant at all time points from 4 to 12 hours postreperfusion (p < 0.01). CONCLUSIONS:These data suggest that, in nonhuman primates, infarcts of a size approaching 20% of the hemisphere may be associated with significant ICP gradients. With these larger infarcts, ipsilateral monitoring is required if regional cerebral perfusion pressure is to be accurately assessed.