Stephen M. Russell

Treatment of giant intracranial aneurysms with saphenous vein extracranial-to-intracranial bypass grafting: Indications, operative technique, and results in 29 patients

OBJECTIVE The treatment of giant intracranial aneurysms is a challenge because of the limitations and difficulty of direct surgical clipping and endovascular coiling. We describe the indications, surgical technique, and complications of saphenous vein extracranial-to-intracranial bypass grafting followed by acute parent vessel occlusion in the management of these difficult lesions. METHODS Between January 1990 and December 1999, 29 patients with giant intracranial aneurysms underwent 30 saphenous vein bypass grafts followed by immediate parent vessel occlusion. There were 11 men and 18 women with a mean follow-up period of 62 months. Twenty-five patients harbored aneurysms involving the internal carotid artery, 2 had middle cerebral artery aneurysms, and 2 had aneurysms in the basilar artery. Serial cerebral or magnetic resonance angiograms were obtained to assess graft patency and aneurysm obliteration. RESULTS All 30 aneurysms were excluded from the cerebral circulation, with 28 vein grafts remaining patent. Two patients had graft occlusions: one because of poor runoff and the other because of misplacement of a cranial pin during a bypass procedure on the contralateral side. Other surgical complications included one death from a large cerebral infarction, homonymous hemianopsia from thrombosis of an anterior choroidal artery after internal carotid artery occlusion, and temporary hemiparesis from a presumed perforator thrombosis adjacent to a basilar aneurysm. CONCLUSION With appropriate attention to surgical technique, a saphenous vein extracranial-to-intracranial bypass followed by acute parent vessel occlusion is a safe and effective method of treating giant intracranial aneurysms. A high rate of graft patency and adequate cerebral blood flow can be achieved. Thrombosis of perforating arteries caused by altered blood flow hemodynamics after parent vessel occlusion may be a continuing source of complications.

INCIDENCE AND CLINICAL EVOLUTION OF POSTOPERATIVE DEFICITS AFTER VOLUMETRIC STEREOTACTIC RESECTION OF GLIAL NEOPLASMS INVOLVING THE SUPPLEMENTARY MOTOR AREA

OBJECTIVE We report the incidence and clinical evolution of postoperative deficits and supplementary motor area (SMA) syndrome after volumetric stereotactic resection of glial neoplasms involving the posterior one-third of the superior frontal convolution. We investigated variables that may be associated with the occurrence of SMA syndrome. METHODS The postoperative clinical status of 27 consecutive patients who underwent resection of SMA gliomas was retrospectively reviewed. Neurological examination results were recorded 1 day, 1 week, 1 month, and 6 months postoperatively. The extent of tumor resection, the percentage of SMA resection, violation of the cingulate gyrus, and operative complications were tabulated. RESULTS The overall incidence of SMA-related deficits was 26% (7 of 27 patients), with 3 patients having complete SMA syndrome and 4 patients having partial SMA syndrome. Two additional patients (7.5%) had other postoperative deficits, including one with mild facial weakness and one with transient aphasia. The resection of low-grade gliomas was associated with a higher incidence of SMA syndrome, an outcome that likely reflects more complete removal of functional SMA cortex in this subset of patients. Intraoperative monitoring localized the precentral sulcus within the preoperatively defined tumor volume in 6 (22%) of 27 patients, thereby precluding gross total resection. All 27 patients had excellent outcomes at the 6-month follow-up examination. CONCLUSION When the resection of SMA gliomas is limited to the radiographic tumor boundaries, the incidence and severity of SMA syndrome may be minimized. With the use of these resection parameters, patients with high-grade SMA gliomas are unlikely to experience SMA syndrome. These findings are helpful in the preoperative counseling of patients who are to undergo cytoreductive resection of SMA gliomas.

The Microsurgical Nuances of Resecting Tuberculum Sellae Meningiomas

In a recent article, our experience and knowledge of the clinical picture, microsurgical anatomy, and long-term surgical outcome of resecting tuberculum sellae meningiomas was described in detail. We now present our surgical technique in a pictorial and video format for the benefit of neurosurgeons in training, as well as for general critique. Attention is given to the details of surgery: patient positioning, surgical approaches, technique of tumor removal, and postoperative care.

Role of frameless stereotaxy in the surgical treatment of cerebral arteriovenous malformations : Technique and outcomes in a controlled study of 44 consecutive patients

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.

Medial sphenoid ridge meningiomas: classification, microsurgical anatomy, operative nuances, and long-term surgical outcome in 35 consecutive patients.

OBJECTIVE On the basis of contemporary multiplanar imaging, microsurgical observations, and long-term follow-up in 60 consecutive patients with sphenoid ridge meningiomas, we propose a modification to Cushings classification of these tumors. This article will concentrate on patients from this series with global medial sphenoid ridge tumors. METHODS Data were collected prospectively for 35 patients with global meningiomas arising from the medial portion of the sphenoid ridge that were surgically treated between 1982 and 2002. RESULTS All patients were followed for the entire length of this study (mean, 12.8 yr). The tumor size ranged from 2 to 8 cm (mean, 4.5 cm). Of the 24 patients with purely intradural tumors, four (17%) had Simpson Grade I and 19 had Simpson Grade II resections; 23 (96%) had gross total resections. Of the 11 patients with tumors extending extradurally (i.e., cavernous sinus), one (9%) patient had a Simpson Grade II resection, whereas nine (82%) had Simpson Grade III resections, with the latter being all visible tumor removed except that in the cavernous sinus. One (9%) of these 11 patients had a gross total resection, and 9 (82%) had radical resections, with the latter defined as total removal of all intradural tumor. The overall morbidity rate was 18%. There was no surgical mortality or symptomatic cerebral infarction. CONCLUSION An accurate classification of global medial sphenoid meningiomas is mandatory to gain insight into their clinical behavior and for understanding the long-term efficacy and safety of available treatment options. Primary medial sphenoid ridge tumors consistently involve the unilateral arteries of the anterior cerebral circulation, and therefore, the resection of tumor from around these arteries is the most important operative nuance for their safe excision.

Glioma vascularity correlates with reduced patient survival and increased malignancy

BACKGROUND The objective of this study was 2-fold: (1) document the presence and degree of vascularity in gliomas of different pathologic grades and (2) determine whether the presence of abnormal vascularity, determined by catheter angiography, correlates with a shortened survival. METHODS As part of a protocol for radiographic data acquisition that was used in a computer-assisted, stereotactic system, all patients who underwent biopsy or resection of a newly diagnosed glioma between 1994 and 2000 at our institution routinely underwent preoperative catheter angiography. The presence and degree of tumor vascularity were recorded and then correlated with survival and pathologic grade. The confounding effects of age, KPS, adjuvant treatment, and extent of resection on survival were considered. RESULTS Two hundred thirty-one patients were included in this study. The mean follow-up of survivors was 7.8 years. Tumor vascularity correlated with a shortened survival (proportional hazards RR for survival, 0.69; 95% CI, 0.58-0.82). This correlation persisted after correction for age, KPS score, adjuvant therapy, and extent of resection (RR, 0.81; 95% CI, 0.68-0.97). Abnormal vascularity was present in 25 (30%) of 82 low-grade (WHO grade 2) gliomas. Overall, the extent of vascularity (none [120 patients, 52%], blush [63 patients, 27%], neovessels [25 patients, 11%], and arteriovenous shunting [23 patients, 10%]) correlated with worse WHO tumor grade (P < .0001). CONCLUSIONS The presence of abnormal vascularity correlates with both a shortened survival and higher grade of malignancy. These findings underscore the importance of antiangiogenesis factor investigation and drug development for the treatment of gliomas, regardless of their pathologic grade.

Volumetric Stereotaxy and the Supratentorial Occipitosubtemporal Approach in the Resection of Posterior Hippocampus and Parahippocampal Gyrus Lesions

OBJECTIVE Resection of intracranial tumors in the posterior hippocampus and the parahippocampal gyrus can be associated with significant morbidity because of the parenchymal resection and the cortical retraction often required in gaining access to this infrequently explored region. With the use of image guidance, the occipitosubtemporal (OST) approach requires neither lateral cortical resection nor the placement of brain retractors to gain surgical access to the posterior hippocampus and the parahippocampal gyrus, and this approach is associated with a high rate of gross total tumor resection. METHODS The computer-assisted volumetric stereotactic OST approach was used to resect 40 posterior hippocampus and parahippocampal gyrus tumors in 34 consecutive patients during an 8-year period. Patient, radiographic, and surgical outcome data were collected retrospectively. RESULTS The series included operations in 25 men and 15 women, and the patients’ average age was 40.3 years (range, 15–69 yr). Twenty-five of the 40 procedures were performed to remove lesions in the dominant hemisphere, and previous craniotomies for resection had been performed in 12 of 40 cases. In 38 of 40 cases, histopathological analysis revealed a glial neoplasm, and 50% of these tumors were high-grade lesions. Preoperatively, 23 patients were neurologically intact before 40 procedures, whereas visual field deficits were noted in 7 patients, mild hemiparesis was documented in 4 patients, and other neurological deficits were present in 9 patients. An excellent outcome (Glasgow Outcome Scale Grade 5) was noted after 38 (95%) of the 40 computer-assisted volumetric stereotactic OST procedures. Permanent postoperative hemiparesis (Glasgow Outcome Scale Grade 4) occurred after one procedure, and a second patient, despite being neurologically unchanged postoperatively and despite having had an optimal tumor resection, died on postoperative Day 33 (Glasgow Outcome Scale Grade 1). Complete resection of the preoperatively defined tumor volume was noted on postoperative gadolinium-enhanced magnetic resonance imaging examinations after 39 (97.5%) of the 40 procedures. The average duration of clinical follow-up was 15.9 months (range, 0.5–67 mo). CONCLUSION We think that the OST approach is well suited to the resection of tumors in the posterior hippocampus and the parahippocampal gyrus. By allowing the neurosurgeon to avoid unnecessary brain resection and retraction, this approach reduces the risk of injury to important lateral temporal and occipital lobe cortex and tracts. In addition, the resection of a posterior hippocampus or parahippocampal gyrus mass with the OST approach relieves temporal horn entrapment. Computer-assisted volumetric stereotaxy helps the neurosurgeon to maintain precise spatial and anatomic orientation and accurately delineates the margin between the tumor and the surrounding neural tissue.

The Anterior Surgical Approach to the Cervical Spine for Intervertebral Disc Disease

THE ANTERIOR SURGICAL APPROACH to the cervical spine in patients with discogenic compressive pathological findings causing radiculopathy or myelopathy is a commonly performed operation with several technical variations. We describe the normal and pathological anatomy and the techniques of surgical decompression of the dura with autograft fusion, which we have used for the past 35 years.

Improvement of chronic hearing loss after shunt revision. A case report.

BACKGROUND Hearing loss after intracranial and spinal procedures involving cerebrospinal fluid loss is rarely reported in the literature. We report a patient who suffered from delayed hearing loss after cerebrospinal fluid shunting that improved after revising the shunt to a higher-pressure valve. CASE DESCRIPTION A 32-year-old woman presented with bilateral hearing loss 4 years after ventriculoperitoneal shunting for communicating hydrocephalus. Her otologic work-up revealed sensorineural hearing loss. In an attempt to improve her hearing, 6 years after the hearing loss began (10 years after the shunt was placed), she underwent a shunt revision in which her valve was changed to a higher-pressure device. After the procedure, she had a significant improvement in her speech discrimination and a mild improvement in her pure tone recognition. These changes were documented with serial audiograms. CONCLUSION Hearing loss after cerebrospinal shunting procedures is not always limited to the immediate postoperative period. It may be a late complication of cerebrospinal fluid diversion. Chronic hearing loss after ventriculoperitoneal shunting may be treatable by changing the valve to a higher-pressure device. The etiology of hearing loss from intracranial hypotension is briefly discussed.

Evaluating middle cerebral artery collateral blood flow reserve using acetazolamide transcranial Doppler ultrasound in patients with carotid occlusive disease

BACKGROUND The objective of this study is to examine the utility of acetazolamide TCD ultrasound in the evaluation of MCA collateral blood flow reserve in patients with carotid occlusive disease. METHODS Acetazolamide TCD and cerebral angiography were performed for 28 carotid territories in 14 patients with carotid occlusive disease. The percentage change in mean blood flow velocity and PI in the MCA was measured before and after 1 g of acetazolamide was administered. The carotid territories were divided into groups according their angiographic findings: (1) mild/moderate (<70%) vs severe (> or =70%) extracranial carotid artery stenosis, and (2) active collateral blood flow to the MCA territory vs no collateral blood flow to the MCA. RESULTS After acetazolamide injection, the percentage increase in mean MCA velocity for mild/moderate vs severe carotid artery stenosis was 43% +/- 10% and 19% +/- 6%, respectively, indicating less collateral blood flow reserve in patients with severe stenosis (P = .04). The percentage decrease in the PI for MCA territories with vs without angiographic evidence of collateral blood flow was 4.6% +/- 4% and 16% +/- 3%, respectively (P = .04), indicating an exhausted vascular reserve in patients with evidence of active collateral blood flow on angiography. CONCLUSIONS A decrease in the PI after acetazolamide administration represents a safe and noninvasive indicator of limited collateral blood flow reserve to the MCA territory ipsilateral to an extracranial carotid stenosis. Further study into the role acetazolamide TCD has in the preoperative evaluation of these patients, including threshold values, is warranted.