Faculty Bibliography

BACKGROUND: Pituitary adenoma may present with neuro-ophthalmic manifestations and, typically, rapid tumor expansion is the result of apoplexy. Herein, we present the first case of an isolated sixth cranial nerve palsy as initial feature of a rapidly expanding ACTH positive silent tumor without apoplexy. CASE PRESENTATION: A 44 year old female with a history of sarcoidosis presented with an isolated sixth cranial nerve palsy as the initial clinical feature of a rapidly expanding ACTH positive silent pituitary adenoma. The patient underwent emergent transsphenoidal hypophysectomy for this rapidly progressive tumor and subsequently regained complete vision and ocular motility. Despite tumor extension into the cavernous sinus, the other cranial nerves were spared during the initial presentation. CONCLUSIONS: This case illustrates the need to consider a rapidly growing pituitary tumor as a possibility when presented with a rapidly progressive ophthalmoplegia

Giant cell tumors (GCTs) and aneurysmal bone cysts (ABCs) are locally aggressive but benign lesions typically of the long bones of the extremities or spine and rarely involve the cranial vault or skull base. Although they are distinct entities pathologically and cytogenetically, GCTs can occur with secondary ABCs, which are likely reactive in nature. The reported cases have primarily involved bones of the extremities and, to our knowledge, there has been only one case of coexisting GCT and ABC of the calvarium or skull base. We describe a 27-year old woman who underwent complete resection of a GCT with secondary ABC of the left occipital bone and condyle. We discuss the significance of the co-occurrence of these lesions and their optimal management

OBJECTIVE: To describe a frameless stereotactic technique used to resect cerebral arteriovenous malformations (AVMs) and to determine whether frameless stereotaxy during AVM resection could decrease operative times, minimize intraoperative blood losses, reduce postoperative complications, and improve surgical outcomes. METHODS: Data for 44 consecutive patients with surgically resected cerebral AVMs were retrospectively reviewed. The first 22 patients underwent resection without stereotaxy (Group 1), whereas the next 22 patients underwent resection with the assistance of a frameless stereotaxy system (Group 2). RESULTS: The patient characteristics, AVM morphological features, and percentages of preoperatively embolized cases were statistically similar for the two treatment groups. The mean operative time for Group 1 was 497 minutes, compared with 290 minutes for Group 2 (P = 0.0005). The estimated blood loss for Group 1 was 657 ml, compared with 311 ml for Group 2 (P = 0.0008). Complication rates, residual AVM incidences, and clinical outcomes were similar for the two groups. CONCLUSION: Frameless stereotaxy allows surgeons to 1) plan the optimal trajectory to an AVM, 2) minimize the skin incision and craniotomy sizes, and 3) confirm the AVM margins and identify deep vascular components during resection. These benefits of stereotaxy were most apparent for small, deep AVMs that were not visible on the surface of the brain. Frameless stereotaxy reduces the operative time and blood loss during AVM resection

BACKGROUND AND PURPOSE: Genetic factors for brain arteriovenous malformation are unexplored because of the low incidence of familial cases, albeit local and familial clustering. We used a combination of a linkage study and an association study to explore the genetic background. METHODS: A genome-wide linkage analysis was performed in 12 patients from 6 unrelated families using the GENEHUNTER program. A genome-wide association analysis of 26 cases and 30 controls was performed using a GeneChip 10K mapping array. Significance levels for linkage and single single-nucleotide polymorphism association analyses were set at P<0.05 and P<0.0001, respectively. Genotyping was also performed using 58 960 single-nucleotide polymorphisms for 2 sets of discordant twins. RESULTS: The linkage analysis revealed 7 candidate regions, with the highest logarithm of odds score of 1.88 (P=0.002) at chromosome 6q25. A significant association was observed for 4 single-nucleotide polymorphisms and 2 haplotypes, but none of them overlapped with candidate linkage regions. Genotyping of the twins showed no genetic heterogeneity. CONCLUSIONS: The present study failed to identify genetic factors for arteriovenous malformation although the low statistical power may have resulted in such evidence being missed

Background and aims: Genetic factors for brain arteriovenous malformation (AVM) are unexplored due to the low incidence of familial cases, albeit local and familial clustering 1. To circumvent such difficulties, we conducted a combination of a pedigree-based linkage analysis and a population-based association analysis in the Takayama community2. Subjects: The study was approved by the Ethics Committee of Kyoto University Institutional Review Board. A total of 12 patients with AVM, from 6 families, participated in the linkage analysis. We recruited 26 unrelated cases (17 men and 9 women) and 30 controls (14 men and 16 women) for the association analysis. Two sets of identical twins from Takayama, with discordant phenotypes, also participated. Methods: Linkage Analysis: A genome-wide linkage analysis was performed in 12 patients from 6 unrelated families using the GENEHUNTER program3. Association Analysis: A genome-wide association analysis of 26 cases and 30 controls was performed using a GeneChip 10K mapping array. Statistical Criteria for the Selection of Candidate Genes: In the linkage analysis, we considered p<0.05 to be an evidence of suggestive linkage. In the single SNP association analysis, p<0.0001 was considered to be statistically significant. Results: With a dominant model, the linkage analysis revealed 7 candidate regions (Table 1). With a recessive model, a significant p value was only obtained at 6q25 (p=0.005, data not shown). The highest LOD score of 1.88 was obtained at D6S1581 with a dominant model (Table 1). Association analyses revealed 4 SNPs and 2 haplotypes with a significant association (Table 2). Conclusions: We minimized the population stratification by selecting a study population within the Takayama community, where clusters of sporadic AVM and familial AVM have been reported4. However, the present study failed to identify genetic factors for AVM, although the low statistical power may have resulted in such evidence being missed

OBJECTIVE: The purposes of this article are to summarize recent developments and concerns in endovascular aneurysm therapy leading to the adjunctive use of endoluminal devices, to review the published literature on stent-supported coil embolization of cerebral aneurysms, and to describe our experience with this technique in a limited subgroup of problematic complex aneurysms over a medium-term follow-up period. METHODS: Between January 2003 and June 2004, 28 individuals among 157 patients with cerebral aneurysms we evaluated were identified as harboring aneurysms with exceptionally broad necks. Out of these 28 patients, 16 were treated with a combination of stents and detachable coils, preserving the parent artery. Recorded data included patient demographics, the clinical presentation, aneurysm location and characteristics, procedural details, and clinical and angiographic outcome. RESULTS: Over an 18-month period, 16 patients with large cerebral aneurysms additionally characterized by neck sizes between 7 and 14 mm were treated, using combined coil embolization of the aneurysm with stent reconstruction of the aneurysm neck. Thirteen out of the 16 aneurysms were occluded at angiographic reevaluation between 11 and 24 months (mean angiographic follow-up, 17.5 mo). There were no treatment-related deaths or clinically evident neurological complications. Thirteen patients experienced excellent clinical outcomes, with good outcomes in two patients and a poor visual outcome in one patient (mean clinical follow-up, 29 mo). A single technical complication occurred, involving transient nonocclusive stent-associated thrombus, which was treated uneventfully with abciximab. CONCLUSION: Stent-supported coil embolization of large, complex-neck cerebral aneurysms seems to provide superior medium-term anatomic reconstruction of the parent artery compared with historic series of aneurysms treated exclusively with endosaccular coils. In the near future, increasingly sophisticated endoluminal devices offering higher coverage of the neck defect will likely enable more definitive endovascular treatment of complex cerebral aneurysms and further expand our ability to manipulate the vascular biology of the parent artery

OBJECTIVE: Meningiomas, although histologically benign, pose a particular challenge to the neurosurgeon because of their extensive and exuberant vascularity. They often bleed extensively during resection until separated from their blood supply. There are a wide variety of hemostatic agents available to the neurosurgeon. Most of these means of hemostasis involve some sort of chemical, electrical, or compressive action. Although anecdotally known to be useful, the use of hydrogen peroxide as an intracranial hemostatic agent in meningioma surgery has not been formally reported. We report a technique of meningioma resection that uses intratumoral hydrogen peroxide injection, reducing the potential for blood loss and shortening resection times. METHODS: Seventy-five patients underwent resection of a meningioma using the direct intratumoral H2O2 injection technique. The locations of these meningiomas included convexity and cranial-based lesions. None of the patients underwent preoperative endovascular embolization. RESULTS: The use of this technique greatly facilitated the removal of these tumors. No evidence of air embolism occurred during Doppler surveillance and no other significant side effects attributable to H2O2 application were observed. CONCLUSION: We demonstrate a previously unreported technique of meningioma resection that uses direct intratumoral hydrogen peroxide injection, potentially reducing blood loss, shortening resection times, and obviating the need for preoperative embolization

BACKGROUND: The purpose of this study was to report our operative technique and lessons learned using saphenous vein conduits to revascularize the rostral basilar circulation (ie, bypass to the posterior cerebral or superior cerebellar arteries). We also review the evolution of this technique for the treatment of vertebrobasilar insufficiency (VBI) and complex posterior fossa aneurysms. METHODS: Data were collected retrospectively for 8 consecutive patients undergoing rostral basilar circulation saphenous vein bypass grafts at our institution between 1989 and 2004 for the treatment of VBI or in conjunction with Hunterian ligation of complex posterior circulation aneurysms. The indications for treatment, pre- and postoperative neurologic status, angiographic results, operative complications, and long-term clinical outcomes were analyzed for each patient. RESULTS: With clinical and angiographic follow-up ranging from 3 months to 15 years, 7 of 8 bypasses remained patent, 3 of 3 aneurysms remained obliterated, and 4 of 5 patients with VBI experienced resolution of their preoperative symptoms. There were no surgery-related deaths, but 2 patients did experience major neurologic morbidity. The outcomes for the 217 total patients reported in the literature were as follows: 135 excellent (62%), 26 good (12%), 30 poor (14%), and 26 dead (12%). CONCLUSIONS: Despite the risk of serious neurologic complications with this procedure, when one considers the natural history of untreated patients, saphenous vein revascularization of the rostral basilar circulation remains an acceptable option. Although surgical technique has varied, patient selection criteria, graft patency, and patient outcomes have been relatively constant over the past 25 years

OBJECTIVE AND IMPORTANCE/OBJECTIVE:Locked-in syndrome is a state of preserved consciousness in the setting of quadriplegia, anarthria, and usually also includes lateral gaze palsy. It is most commonly associated with upper brainstem infarction variably sparing the third cranial nerve nucleus. There are likely many etiologies that contribute to this clinical syndrome. These are incompletely understood, and the syndrome remains a rare but devastating complication that can occur after neurosurgical and neurovascular interventions. Advanced magnetic resonance imaging techniques such as perfusion and diffusion tensor imaging may help to elucidate the mechanism behind locked-in syndrome. To the authors' knowledge, there are no reports in the literature of perfusion and diffusion tensor findings in patients with this syndrome. A postprocedural case of locked-in syndrome is described with abnormalities on perfusion and diffusion tensor imaging in the absence of any changes in conventional magnetic resonance imaging. CLINICAL PRESENTATION/METHODS:A 57-year-old man who presented with acute onset headache, ataxia, and other nonspecific symptoms was found on imaging to have a giant fusiform basilar artery aneurysm. INTERVENTION/METHODS:A saphenous vein graft bypass between the proximal right external carotid artery and P2 segment of the right posterior cerebral artery followed immediately by endovascular embolization of the aneurysm sac and distal left vertebral artery was performed. CONCLUSION/CONCLUSIONS:Postprocedural angiography demonstrated patency of the bypass graft, and diffusion weighted imaging showed no evidence for acute brainstem infarction. Nevertheless, despite technically successful procedures and the absence of abnormalities on conventional magnetic resonance imaging, the patient developed quadriplegia and anarthria and remained in a locked-in state until he expired. Abnormalities were, however, seen on both perfusion and diffusion tensor imaging, where hypoperfusion, increased mean diffusivity, and decreased fractional anisotropy were observed in the ventral brainstem. The findings suggested a disruption of pontine white matter tracts. Advanced imaging techniques may allow us to image important microstructural changes that were previously not discernable and assist in the evaluation of patients with complex neurological sequelae such as locked-in syndrome.

OBJECTIVE: The pretemporal approach has gained popularity for the treatment of basilar apex aneurysms. However, it requires the sacrifice of anterior temporal bridging veins to allow posterior temporal lobe retraction and, for patients with dominant pretemporal venous drainage, has the attendant risk of venous hypertension, hemorrhagic venous infarction, or seizures postoperatively. Alternatively, we have found that splitting the sylvian fissure, resecting the uncus, and applying posterolateral retraction to the medial temporal lobe provides a similar exposure to the basilar apex while preserving the anterior temporal bridging veins. To evaluate the transsylvian, trans-uncal approach to the basilar apex, we report our initial clinical results using this exposure in eight consecutive patients. A morphometric cadaveric analysis comparing this approach with the pretemporal approach was also performed. METHODS: For the clinical study, all hospital charts and imaging studies were retrospectively reviewed for patients undergoing the transsylvian, trans-uncal approach for the treatment of an upper basilar trunk aneurysm between July 2000 and July 2002. In the anatomic study, six formalin-fixed cadaver specimens were used. Two sequential exposures of the basilar apex were performed on each specimen side. First, the pretemporal exposure was performed with anteroposterior temporal lobe retraction. Next, after the temporal lobe had been allowed to return to normal anatomic position, the retractor was repositioned on the medial aspect of the temporal lobe superficial to the uncus, and a 10 x 10 x 15-mm volume of uncus was removed. Morphometric measurements were performed for each exposure. RESULTS: Four basilar bifurcation and four superior cerebellar segment aneurysms in eight consecutive patients were successfully clip-ligated by use of the transsylvian, trans-uncal approach. All patients had temporal bridging veins that were preserved, as documented by angiography and operative reports. No patient developed a venous infarction or new postoperative seizures, with a mean follow-up of 9.75 months (range, 0.5-28 mo). The cadaveric analysis revealed that in addition to providing a similar exposure of the upper basilar complex, the transsylvian, trans-uncal approach provided additional exposure of the ipsilateral posterior cerebral and superior cerebellar arteries compared with the pretemporal approach. CONCLUSION: When approaching the basilar bifurcation, the transsylvian, trans-uncal approach provides superior exposure of the ipsilateral superior cerebellar and posterior cerebral arteries compared with the pretemporal approach, while preserving the anterior temporal bridging veins. This approach is most valuable in patients with dominant temporal venous drainage or when additional exposure of the ipsilateral posterior cerebral or superior cerebellar arteries is required