Faculty Bibliography

The authors report a case of primary CNS lymphoma located in the floor of the fourth ventricle that showed intense fluorescence after preoperative administration of 5-aminolevulinic acid. The authors believe that this is the first demonstration of a 5-aminolevulinic acid-induced fluorescence pattern in primary CNS lymphoma.

Complete tumor resection with preservation or improvement of visual function is the goal of tuberculum sellae meningioma (TSM) treatment. The authors retrospectively reviewed 51 patients treated surgically for TSM between 2003 and 2010, with special attention to surgical technique, visual outcomes, and prognostic factors for treatment outcome. All patients were operated via the lateral subfrontal approach. The cohort mean age and Karnofsky performance status (KPS) on admission was 57.1 ± 13.6 and 84.3 ± 11.7, respectively. The most common presenting sign was visual impairment. The mean tumor size was 29.4 ± 10.7 mm. In 45 of the patients (88.2%), gross total resection was achieved. Improvement and/or preservation of visual acuity and visual field were achieved in 95.9% and 85.3%, respectively. Visual functions on admission were found to be the strongest predictors for postoperative improvement in visual outcome, followed by better KPS on admission, smaller tumor size, and young age. Postoperative neurological complications included cerebrospinal fluid (CSF) leak, meningitis, and postoperative seizures. TSM can be safely operated on through the lateral subfrontal approach. A high percentage of complete tumor resection and excellent visual outcomes are achieved using this technique. Surgical treatment in the early stage of the disease may result in a better visual outcome.

BACKGROUND: Awake craniotomy (AC) for removal of intra-axial brain tumors is a well-established procedure. However, the occurrence and consequences of intraoperative seizures during AC have not been well characterized. OBJECTIVE: To analyze the incidence, risk factors, and consequences of seizures during AC. METHODS: The database of AC at Tel Aviv Medical Center between 2003 to 2011 was reviewed. Occurrences of intraoperative seizures were analyzed with respect to medical history, medications, tumor characteristics, and postoperative outcome. RESULTS: Of the 549 ACs performed during the index period, 477 with complete records were identified. Sixty patients (12.6%) experienced intraoperative seizures. The AC procedure failed in 11 patients (2.3%) due to seizures. Patients with intraoperative seizures were significantly younger than nonseizing patients (45 +/- 14 years vs 52 +/- 16 years, P = .003), had a higher incidence of frontal lobe involvement (86% vs % 57%, P < .0001), and had higher prevalence of a history of seizures (P = .008). Short-term motor deterioration developed postoperatively in a higher percentage of patients with intraoperative seizures (20% vs 10.1%, P = .02) with a longer hospitalization period (4.0 +/- 3.0 days vs 3.0 +/- 3.0 days, P = .045). CONCLUSION: Although in most cases intraoperative seizures will not result in AC failure, the surgical team should be prepared to treat them promptly to avoid intractable seizures. Intraoperative seizures are more common in younger patients with a tumor in the frontal lobe and those with a history of seizures. Moreover, they are associated with a higher incidence of transient postoperative motor deterioration and protracted length of hospital stay.

BACKGROUND: Awake-craniotomy allows maximal tumor resection, which has been associated with extended survival. The feasibility and safety of awake-craniotomy and the effect of extent of resection on survival in the elderly population has not been established. The aim of this study was to compare surgical outcome of elderly patients undergoing awake-craniotomy to that of younger patients. METHODS: Outcomes of consecutive patients younger and older than 65 years who underwent awake-craniotomy at a single institution between 2003 and 2010 were retrospectively reviewed. The groups were compared for clinical variables and surgical outcome parameters, as well as overall survival. RESULTS: A total of 334 young (45.4 +/- 13.2 years, mean +/- SD) and 90 elderly (71.7 +/- 5.1 years) patients were studied. Distribution of gender, mannitol treatment, hemodynamic stability, and extent of tumor resection were similar. Significantly more younger patients had a better preoperative Karnofsky Performance Scale score (>70) than elderly patients (P = 0.0012). Older patients harbored significantly more high-grade gliomas (HGG) and brain metastases, and fewer low-grade gliomas (P < 0.0001). No significantly higher rate of mortality, or complications were observed in the elderly group. Age was associated with increased length of stay (4.9 +/- 6.3 vs. 6.6 +/- 7.5 days, P = 0.01). Maximal extent of tumor resection in patients with HGG was associated with prolonged survival in the elderly patients. CONCLUSIONS: Awake-craniotomy is a well-tolerated and safe procedure, even in elderly patients. Gross total tumor resection in elderly patients with HGG was associated with prolonged survival. The data suggest that favorable prognostic factors for patients with malignant brain tumors are also valid in elderly patients.

OBJECT: Awake craniotomy for removal of intraaxial tumors within or adjacent to eloquent brain regions is a well-established procedure. However, awake craniotomy failures have not been well characterized. In the present study, the authors aimed to analyze and assess the incidence and causes for failed awake craniotomy. METHODS: The database of awake craniotomies performed at Tel Aviv Medical Center between 2003 and 2010 was reviewed. Awake craniotomy was considered a failure if conversion to general anesthesia was required, or if adequate mapping or monitoring could not have been achieved. RESULTS: Of 488 patients undergoing awake craniotomy, 424 were identified as having complete medical, operative, and anesthesiology records. The awake craniotomies performed in 27 (6.4%) of these 424 patients were considered failures. The main causes of failure were lack of intraoperative communication with the patient (n = 18 [4.2%]) and/or intraoperative seizures (n = 9 [2.1%]). Preoperative mixed dysphasia (p < 0.001) and treatment with phenytoin (p = 0.0019) were related to failure due to lack of communication. History of seizures (p = 0.03) and treatment with multiple antiepileptic drugs (p = 0.0012) were found to be related to failure due to intraoperative seizures. Compared with the successful awake craniotomy group, a significantly lower rate of gross-total resection was achieved (83% vs 54%, p = 0.008), there was a higher incidence of short-term speech deterioration postoperatively (6.1% vs 23.5%, p = 0.0017) as well as at 3 months postoperatively (2.3% vs 15.4%, p = 0.0002), and the hospitalization period was longer (4.9 +/- 6.2 days vs 8.0 +/- 10.1 days, p < 0.001). Significantly more major complications occurred in the failure group (4 [14.8%] of 27) than in the successful group (16 [4%] of 397) (p = 0.037). CONCLUSIONS: Failures of awake craniotomy were associated with a lower incidence of gross-total resection and increased postoperative morbidity. The majority of awake craniotomy failures were preventable by adequate patient selection and avoiding side effects of drugs administered during surgery.

The impact of enrollment in a clinical study on the survival of patients with glioblastoma has not been established. We retrospectively analyzed 564 patients with newly diagnosed glioblastoma treated between 1995 and 2008. They were divided into those enrolled in a clinical trial and randomized to a treatment or control arm, and those not enrolled and who received best standard of care (BSC). The three groups were matched for age and Karnofsky performance scale (KPS) score at presentation, and included only patients who underwent at least one tumor resection. Survival analysis was performed and multivariate Cox proportional hazards model and recursive partitioning analysis (RPA) identified predictors of survival. Following the matching process, 261 patients remained to form the final cohort. Of the 124 patients enrolled in a study, 81 (31.0%) were randomized to the treatment and 43 (16.5%) to the control arms. The overall median survival for the BSC (n=137), control, and treatment groups was 11.57 months (95% confidence interval [CI], 10.41-12.73), 16.27 months (95% CI, 14.10-18.43) and 16.10 months (95% CI, 14.34-17.86), respectively (p=0.002). Participation in a clinical trial, regardless of the arm, was a significant predictor of survival, as were age and KPS at diagnosis. The RPA also demonstrated a favorable impact of participation in a clinical trial. Additional tumor resections and various treatment modalities were administered with significantly higher frequency among patients enrolled in clinical studies. Thus, enrollment in a clinical study carried a significant survival advantage for patients with glioblastoma, raising practical and ethical issues regarding the quality of care of patients who receive "standard" therapy.

BACKGROUND: Freezing of gait (FOG) is defined as an episodic inability to generate effective stepping in the absence of any known cause other than parkinsonism or high-level gait disorders. METHODS: We present a 59-year-old male with acute, progressive episodes of FOG. Imaging studies revealed a dural arteriovenous fistula (DAVF) associated with edema of the globus pallidus interna (GPi). Cerebral angiography confirmed the diagnosis of DAVF and demonstrated an occluded straight sinus and a retrograde blood flow of deep cerebral veins. RESULTS: After endovascular closure of the DAVF, a major improvement of FOG was observed concomitant with striking near resolution of GPi congestion. CONCLUSIONS: This reversal of the clinical course, correlated with changes in imaging studies, suggests a major role of the GPi in the pathology of FOG.

BACKGROUND: Flow diverters are recently developed stent-like endovascular devices developed to treat complex and non-coilable aneurysms. SILK is a type of flow diverter that has been used for nearly 3 years. Only sparse data about it are available. We would like to share our experience with this device. METHODS: Twenty-eight patients were treated with SILK from October 2008 to October 2010. Thirty-one treatment sessions were performed for 32 aneurysms using 31 SILKs. Twenty have been treated with SILK only and eight with SILK and adjuvant stents. Twenty-six (86%) patients performed cross-sectional imaging (MRA/CTA) for follow-up. Eighteen (64%) patients had follow-up brain angiography. RESULTS: In all patients the SILK could be deployed. No case of early or late aneurysmal rupture was noted. Five patients (17.8%) developed immediate clinical complications, which were permanent in three (10.7%). All the complications occurred in patients harboring aneurysms larger than 15 mm. In two other patients, occlusion of the SILK was noted with no clinical deficit. A complete or near-complete aneurysmal occlusion was found in brain angiography or cross-sectional imaging follow-up in 83.3% of the patients. CONCLUSIONS: SILK is a relatively simple device to use, with a low rate of technical and clinical complications and a high short-term aneurysmal occlusion rate. In aneurysms smaller than 15 mm, the results are excellent. Results are also encouraging in the larger aneurysms, taking into consideration their complexity. The device characteristics and mainly its drawbacks must be well known by the users.

BACKGROUND: Pregnant women with pathological conditions requiring a neurosurgical intervention pose a unique therapeutic challenge. Changes in normal physiology add to the complexity of patient management. We describe our experience in treating various neurosurgical diseases in parturient women. METHODS: Thirty-four pregnant and early postpartum women were treated at our center between 2003 and 2010. The general guideline used in these patients (now deserving re-evaluation based on the presented data) was to postpone surgery until the patient reached term (weeks 34-38 of gestation) unless there was evidence of a life- or function-threatening condition, in which case surgery was promptly performed. RESULTS: Sixteen patients underwent neurosurgical intervention during pregnancy between 11 to 34 weeks of gestation (7 tumor, 3 vascular, 2 VP shunt, 2 spinal, 2 trauma). Thirteen women underwent a neurosurgical procedure after delivery (12 tumor, 1 spine), and 5 women were treated conservatively (2 vascular lesions, 3 trauma). Three patients underwent abortions (one spontaneous and two elective). The other 31 women delivered at 30-42 weeks' gestation. Of 12 patients whose definitive neurosurgical procedure was initially delayed, 5 were not able to complete their pregnancy naturally. Of 21 patients that underwent a cesarean section (CS), 3 were performed urgently. Although two pairs of twins and two singletons had an initial low Apgar score (<7), the outcome for all the neonates was good. Neurosurgical outcome was satisfactory. CONCLUSIONS: Our experience demonstrates the safety of neurosurgical intervention and anesthesia during pregnancy. Delaying intervention often resulted in maternal deterioration and urgent intervention. Thus, pregnancy by itself should not be considered a major contraindication for performing a neurosurgical procedure, which should be considered early rather than late in most patients.

OBJECT: Preserving motor function is a major challenge in surgery for intraaxial brain tumors. Navigation systems are unreliable in predicting the location of the corticospinal tracts (CSTs) because of brain shift and the inability of current intraoperative systems to produce reliable diffusion tensor imaging data. The authors describe their experience with elaborate neurophysiological assessment and tractography-based navigation, corrected in real time by 3D intraoperative ultrasonography (IOUS) to identify motor pathways during subcortical tumor resection. METHODS: A retrospective analysis was conducted in 55 patients undergoing resection of tumors located within or in proximity to the CSTs at the authors' institution between November 2007 and June 2009. Corticospinal tract tractography was coregistered to surgical navigation-derived images in 42 patients. Direct cortical-stimulated motor evoked potentials (dcMEPs) and subcortical-stimulated MEPs (scrtMEPs) were recorded intraoperatively to assess function and estimate the distance from the CSTs. Intraoperative ultrasonography updated the navigation imaging and estimated resection proximity to the CSTs. Preoperative clinical motor function was compared with postoperative outcome at several time points and correlated with incidences of intraoperative dcMEP alarm and low scrtMEP values. RESULTS: The threshold level needed to elicit scrtMEPs was plotted against the distance to the CSTs based on diffusion tensor imaging tractography after brain shift compensation with 3D IOUS, generating a trend line that demonstrated a linear order between these variables, and a relationship of 0.97 mA for every 1 mm of brain tissue distance from the CSTs. Clinically, 39 (71%) of 55 patients had no postoperative deficits, and 9 of the remaining 16 improved to baseline function within 1 month. Seven patients had varying degrees of permanent motor deficits. Subcortical stimulation was applied in 45 of the procedures. The status of 32 patients did not deteriorate postoperatively (stable or improved motor status): 27 of them (84%) displayed minimum scrtMEP thresholds > 7 mA. Six patients who experienced postoperative deterioration quickly recovered (within 5 days) and displayed minimum scrtMEP thresholds > 6.8 mA. Five of the 7 patients who had late (> 5 days postoperatively) or no recovery had minimal scrtMEP thresholds < 3 mA. An scrtMEP threshold of 3 mA was found to be the cutoff point below which irreversible disruption of CST integrity may be anticipated (sensitivity 83%, specificity 95%). CONCLUSIONS: Combining elaborate neurophysiological assessment, tractography-based neuronavigation, and updated IOUS images provided accurate localization of the CSTs and enabled the safe resection of tumors approximating these tracts. This is the first attempt to evaluate the distance from the CSTs using the threshold of subcortical monopolar stimulation with real-time IOUS for the correction of brain shift. The linear correlation between the distance to the CSTs and the threshold of subcortical stimulation producing a motor response provides an intraoperative technique to better preserve motor function.