Surgery for low-grade glioma infiltrating the central cerebral region

Surgery for low-grade glioma infiltrating the central cerebral region

J Neurosurg 119:318–323, 2013

A main concern with regard to surgery for low-grade glioma (LGG, WHO Grade II) is maintenance of the patient’s functional integrity. This concern is particularly relevant for gliomas in the central region, where damage can have grave repercussions. The authors evaluated postsurgical outcomes with regard to neurological deficits, seizures, and quality of life.

Methods. Outcomes were compared for 33 patients with central LGG (central cohort) and a control cohort of 31 patients with frontal LGG (frontal cohort), all of whom had had medically intractable seizures before undergoing surgery with mapping while awake. All surgeries were performed in the period from February 2007 through April 2010 at the same institution.

Results. For the central cohort, the median extent of resection was 92% (range 80%–97%), and for the frontal cohort, the median extent of resection was 93% (range 83%–98%; p = 1.0). Although the rate of mild neurological deficits was similar for both groups, seizure freedom (Engel Class I) was achieved for only 4 (12.1%) of 33 patients in the central cohort compared with 26 (83.9%) of 31 patients in the frontal cohort (p < 0.0001). The rate of return to work was lower for patients in the central cohort (4 [12.1%] of 33) than for the patients in the frontal cohort (28 [90.3%] of 31; p < 0.0001).

Conclusions. Resection of central LGG is feasible and safe when appropriate intraoperative mapping is used. However, seizure control for these patients remains poor, a finding that contrasts markedly with seizure control for patients in the frontal cohort and with that reported in the literature. For patients with central LGG, poor seizure control ultimately determines quality of life because most will not be able to return to work.

X-Stop Versus Decompressive Surgery for Lumbar Neurogenic Intermittent Claudication

X-stop

Spine 2013 ;38:1436–1442

Objective. To compare the outcome of indirect decompression by means of the X-Stop (Medtronics Inc., Minneapolis, MN) implant with conventional decompression in patients with neurogenic intermittent claudication due to lumbar spinal stenosis.

Summary of Background Data. Decompression is currently the “gold standard” for lumbar spinal stenosis but is affl icted with complications and a certain number of dissatisfi ed patients. Interspinous implants have been on the market for more than 10 years, but no prospective study comparing its outcome with decompression has been performed.

Methods. After power calculation, 100 patients were included: 50 in the X-Stop group and 50 in the decompression group. Patients with symptomatic 1- or 2-level lumbar spinal stenosis and neurogenic claudication relieved on fl exion were included. X-Stop operations were performed under local anesthesia. The mean patient age was 69 (49–89) years, and the male/female distribution was 56/44. Minimal dural sac area was in all cases except two 80 mm 2 or less. The noninferiority hypothesis included 6, 12, and 24 months of follow-up, and included. intention-to-treat as well as as-treated analyses. The primary outcome meansure was the Zürich Claudication Questionnaire, and the secondary outcome measures was the visual analogue scale pain, Short-Form 36 (SF-36), complications, and reoperations.

Results. The primary and secondary outcome measures of patients in both groups improved signifi cantly. The results were similar at 6, 12, and 24 months and at no time point could any statistical difference between the 2 types of surgery be identifi ed. Three patients (6%) in the decompression group underwent further surgery, compared with 13 patients (26%) in the X-Stop group ( P = 0.04). Results were identical in intention-to-treat and astreated analyses.

Conclusion. For spinal stenosis with neurogenic claudication, decompressive surgery as well as X-Stop are appropriate procedures. Similar results were achieved in both groups, however, with a higher number of reoperations in the X-Stop group. Patients having X-Stop removal and decompression experienced results similar to those randomized to primary decompression.

Level of Evidence: 1

Long-term results of posteromedial hypothalamic deep brain stimulation for patients with resistant aggressiveness

Posteromedial hypothalamic DBS for intractable erethism

J Neurosurg 119:277–287, 2013

Erethism describes severe cases of unprovoked aggressive behavior, usually associated with some degree of mental impairment and gross brain damage. The etiology can be epileptic, postencephalitic, or posttraumatic, or the condition can be caused by brain malformations or perinatal insults. Erethism is often refractory to medication, and patients must often be interned in institutions, where they are managed with major restraining measures. The hypothalamus is a crucial group of nuclei that coordinate behavioral and autonomic responses and play a central role in the control of aggressive behavior. Deep brain stimulation (DBS) of the posteromedial hypothalamus (PMH) has been proposed as a treatment for resistant erethism, although experience with this treatment around the world is scarce. The objective of this study was to examine the long-term outcome of PMH DBS in 6 patients with severe erethism treated at the authors’ institution.

Methods. Medical records of 6 patients treated with PMH DBS for intractable aggressiveness were reviewed. The therapeutic effect on behavior was assessed by the Inventory for Client and Agency Planning preoperatively and at the last follow-up visit.

Results. Two patients died during the follow-up period due to causes unrelated to the neurosurgical treatment. Five of 6 patients experienced a significant reduction in aggressiveness (the mean Inventory for Client and Agency Planning general aggressiveness score was -47 at baseline and -25 at the last follow-up; mean follow-up 3.5 years). Similar responses were obtained with low- and high-frequency stimulation. In 4 cases, the patients’ sleep patterns became more regular, and in 1 case, binge eating and polydipsia ceased. One of the 3 patients who had epilepsy noticed a 30% reduction in seizure frequency. Another patient experienced a marked sympathetic response with highfrequency stimulation during the first stimulation trial, but this subsided when stimulation was set at low frequency. A worsening of a previous headache was noted by 1 patient. There were no other side effects.

Conclusions. In this case series, 5 of 6 patients with pathological aggressiveness had a reduction of their outbursts of violence after PMH DBS, without significant adverse effects. Prospective controlled studies with a larger number of patients are needed to confirm these results.

Surgical techniques for the dissection of encased perforators in giant clinoidal meningiomas

Encased perforators in giant clinoidal meningiomas

Acta Neurochir (2013) 155:1409–1412

Surgical treatment of giant clinoidal meningiomas remains a challenging task for neurosurgeons. Here, we present details of the surgical techniques for the dissection of encased perforators.

Methods The dissection of encased perforators is summarized as follows: (1) split the tumor above the encased arteries and perforators; (2) find the entrance and exit points of the perforators, and estimate the running course of the perforators within the tumor; (3) dissect and expose the perforators along the estimated line.

Conclusions The surgical techniques described in this article will aid in achieving maximum tumor resection while preserving encased perforators.

Flow-Diverter Devices for Intracranial Aneurysms

Flow-Diverter Devices for Intracranial Aneurysms

Neurosurgery 73:193–200, 2013

Although the introduction of flow-diverter devices (FDDs) has aroused great enthusiasm, the level of evidence supporting their use has not been systematically evaluated.

OBJECTIVE: To report a systematic review of medical literature up to May 2012 on FDDs to assess the morbidity, case fatality rate, and efficacy of FDDs for intracranial aneurysms.

METHODS: The literature was searched by using MEDLINE, Embase, and all Evidence- Based Medicine in the OVID database. Eligibility criteria were studies including at least 10 patients, reporting duration of follow-up and number of patients lost to follow-up, and documenting the rate of aneurysm occlusion and death and neurological complications. The endpoints were angiographic success, early and late mortality, and neurological morbidity.

RESULTS: Fifteen studies were analyzed consisting of 897 patients with 1018 aneurysms. The mean value of methodological quality score was 14.4 using the STROBE score. The early mortality rate was 2.8% (95% confidence interval [CI]: 1.7-3.8; I2 = 93.4%) and the late mortality rate was 1.3% (95% CI: 0.2-2.3; I2 = 36.9%). The early neurological morbidity rate was 7.3% (95% CI: 5.7-9; I2 = 91.8%) and the late morbidity rate was 2.6% (95% CI: 1.1-4; I2 = 81.3%). The Egger test for early and late morbidity and aneurysm occlusion was ,0.001.

CONCLUSION: With the available data from the studies, both heterogeneity and publication biases imply that the current clinical use of FDDs is not supported by highquality evidence. In the absence of reliable evidence, the use of FDDs in patients eligible for more conventional treatments should be restricted to controlled clinical trials.

Complex middle cerebral artery aneurysms. A new classification

Complex MCAA-a new classification

Acta Neurochir (2013) 155:1481–1491

Because of the diversity of aneurysm morphology, complicated arterial anatomy and hemodynamic characteristics, tailored surgical treatments are required for cases of individual complex middle cerebral artery (MCA) aneurysms.

Methods During an 8-year period, 59 complex MCA aneurysms in 58 patients were treated microsurgically in our department. Complex aneurysms were defined as having large (10–24 mm in diameter) or giant (diameter≥25 mm) size or non-saccular morphology (fusiform, dissecting or serpentine).

Results Direct clipping of the aneurysmal necks was achieved in eight patients, while reconstructive clipping was performed in 25 patients. Indirect aneurysm occlusion was performed in 25 cases, including trapping or resecting the aneurysm in four cases, trapping or resecting the aneurysm with extraintracranial (EC) or intra-intracranial (IC) bypass in 21 cases and internal carotid artery (ICA) sacrifice with EC-IC bypass in one case. Forty-eight aneurysms (81.4 %) were completely obliterated. Graft patency was confirmed in 20 of 21 cases (95.2 %) with bypass. A recurrent aneurysm was detected in one case and a re-operation was performed. Two patients with Hunt-Hess grade IV aneurysms died during the perioperative period. Overall, 52 cases (88.1 %) had good outcomes (Glasgow Outcome Scale≥4) during the late follow-up period.

Conclusion The surgical modality and strategy for treating complex MCA aneurysm are decided according to the morphology of the aneurysm, vascular anatomy and the hemodynamic characteristics of each case. Thus, we developed a new classification based on the angioarchitecture. Favorable outcomes can be achieved by treating complex MCA aneurysms with appropriate surgical modalities, strategies and techniques.

Outcomes After Anterior Cervical Discectomy and Fusion in Professional Athletes

Outcomes After Anterior Cervical Discectomy and Fusion in Professional Athletes

Neurosurgery 73:103–112, 2013

Significant controversy exists regarding when an athlete may return to contact sports after anterior cervical discectomy and fusion (ACDF). Return-to-play (RTP) recommendations are complicated due to a mix of medical factors, social pressures, and limited outcome data.

OBJECTIVE: The aim of this study was to characterize our diagnostic and surgical criteria, intervention, postoperative imaging results, and rehabilitation and report RTP decisions and outcomes for professional athletes with cervical spine injuries.

METHODS: Fifteen professional athletes who had undergone a 1-level ACDF by a single neurosurgeon were identified after a retrospective chart and radiographic review from 2003 to 2012. Patient records and imaging studies were recorded.

RESULTS: Seven of the 15 athletes presented with neurapraxia, 8 with cervical radiculopathy, and 2 with hyperintensity of the spinal cord. Cervical stenosis with effacement of the cerebrospinal fluid signal was noted in 14 subjects. The operative level included C3-4 (4 patients), C4-5 (1 patient), C5-6 (8 patients), and C6-7 (2 patients). All athletes were cleared for RTP after a neurological examination with normal findings, and radiographic criteria for early fusion were confirmed. Thirteen of the 15 players returned to their sport between 2 and 12 months postoperatively (mean, 6 months), with 8 still participating. The RTP duration of the 5 who retired after full participation ranged from 1 to 3 years. All athletes remain asymptomatic for radicular or myelopathic symptoms or signs.

CONCLUSION: After a single-level ACDF, an athlete may return to contact sports if there are normal findings on a neurological examination, full range of neck movement, and solid arthrodesis. There may be an increased risk of the development of adjacent segment disease above or below the level of fusion. Cord hyperintensity may not necessarily preclude RTP.

KEY WORDS:

Tolerance of awake surgery for glioma: a prospective European Low Grade Glioma Network multicenter study

awake surgery for glioma

Acta Neurochir (2013) 155:1301–1308

Gross total removal of glioma is limited by proximity to eloquent brain. Awake surgery allows for intraoperative monitoring to safely identify eloquent regions. However, data on adverse psychological effects induced in these patients is limited.

Objective This study explored patients’ perception of awake surgery for glioma, with special focus on intraoperative pain and anxiety.

Methods This study was conducted at five neurosurgical centers within the European Low Grade Glioma Network. Patients underwent awake surgery for glioma according to the protocol of the individual center. Pain and discomfort were measured during the awake phase. Postoperatively, patients answered a questionnaire on aspects of their operation.

Results One hundred five patients were enrolled. Pain levels on a 10-cm visual analogue scale were 1.3 cm at the beginning, 1.9 cm the middle, and 2.1 cm at the end of awake phase. Levels of anxiety were 2.2 cm, 2.5 cm and 2.6 cm, respectively. Women and patients younger than 60 years exhibited highest mean anxiety levels. The patient questionnaire revealed that the majority of patients feel comfortable with the procedure. Discomfort resulted from head fixation or positioning on the operating table.

Conclusions We demonstrate that awake surgery is well tolerated, as neither intraoperative nor postoperative assessment revealed major disadvantages. Concerning practical lessons learned from this study, we emphasize the importance of minimizing pain and preparing patients thoroughly to reduce anxiety and maximize cooperation. Awake surgery is an excellent treatment modality for brain tumors with very positive perception by patients. Keywords

Spinal Pial (Type IV) Arteriovenous Fistulae

Spinal Pial (Type IV) Arteriovenous Fistulae

Neurosurgery 73:141–151, 2013

Demographics, hemorrhage risk, and results of surgical and endovascular treatment of spinal pial (type IV) arteriovenous fistulae (AVFs) across a large patient group have not been previously reported.

OBJECTIVE: To report demographics, hemorrhage rates, and treatment results for these AVFs.

METHODS: We performed a pooled analysis via the PubMed and Embase databases through November 2012. Individualized patient data were extracted and analyzed using Cox proportional hazards regression to obtain hazard ratios for hemorrhage risk factors and pooled for baseline demographics and treatment results.

RESULTS: We extracted information on 213 patients from 28 studies. Only 1% of lesions were incidental; 93% of patients presented with neurologic deficits and 36% with hemorrhage. Patients with type IVa lesions were significantly older (mean age, 46.9 years) and demonstrated a male sex predilection (68% male). Patients with type IVc lesions were significantly younger (mean age, 18.7 years), had no sex predilection, and had the highest prevalence of syndromic conditions (29% of cases). The annual hemorrhage rate was 2.5% (95% confidence interval [CI]: 1.4%-4.7%), increasing to 5.6% for hemorrhagic fistulae (95% CI: 3.0%-10.7%; hazard ratio: 6.31; 95% CI: 0.69-57.4; P = .10). Patient sex, fistula location, and fistula subclass were not significant risk factors for hemorrhage. The surgical obliteration rate was 88%; 68% of patients improved, 26% were the same, and 6% were worse. The endovascular obliteration rate was 74%; 75% of patients improved, 14% were the same, and 11% were worse.

CONCLUSION: We demonstrate the utility of the Anson-Spetzler a-c subclassification and underscore the efficacy of surgical and endovascular spinal AVF treatment.

Interactive presurgical simulation applying 3D techniques

Presurgical simulation 3Dimaging

J Neurosurg 119:94–105, 2013

In this paper, the authors’ goal was to report their novel presurgical simulation method applying interactive virtual simulation (IVS) using 3D computer graphics (CG) data and microscopic observation of color-printed plaster models based on these CG data in surgery for skull base and deep tumors.

Methods. For 25 operations in 23 patients with skull base or deep intracranial tumors (meningiomas, schwannomas, epidermoid tumors, chordomas, and others), the authors carried out presurgical simulation based on 3D CG data created by image analysis for radiological data. Interactive virtual simulation was performed by modifying the 3D CG data to imitate various surgical procedures, such as bone drilling, brain retraction, and tumor removal, with manipulation of a haptic device. The authors also produced color-printed plaster models of modified 3D CG data by a selective laser sintering method and observed them under the operative microscope.

Results. In all patients, IVS provided detailed and realistic surgical perspectives of sufficient quality, thereby allowing surgeons to determine an appropriate and feasible surgical approach. Surgeons agreed that in 44% of the 25 operations IVS showed high utility (as indicated by a rating of “prominent”) in comprehending 3D microsurgical anatomies for which reconstruction using only 2D images was complicated. Microscopic observation of color-printed plaster models in 12 patients provided further utility in confirming realistic surgical anatomies.

Conclusions. The authors’ presurgical simulation method applying advanced 3D imaging and modeling techniques provided a realistic environment for practicing microsurgical procedures virtually and enabled the authors to ascertain complex microsurgical anatomy, to determine the optimal surgical strategies, and also to efficiently educate neurosurgical trainees, especially during surgery for skull base and deep tumors.

Venous preservation–guided resection: a changing paradigm in parasagittal meningioma surgery

Venous preservation–guided resection- a changing paradigm in parasagittal meningioma surgery-1

J Neurosurg 119:74–81, 2013

Surgical treatment of parasagittal meningiomas is challenging. Preserving the venous outflow is the key point, but this may preclude radical resection. Different surgical strategies have been proposed. To contribute to the debate on the optimal strategy for treating these tumors, a single-institutional, single-surgeon series of patients with parasagittal meningiomas was analyzed and the available literature reviewed.

Methods. Clinical charts of patients with parasagittal meningioma, managed at the University of Messina between 1988 and 2008, were retrospectively reviewed. A microsurgical resection, the goal of which was to preserve the venous outflow, was performed. Only if the superior sagittal sinus (SSS) was angiographically occluded, but if alternative venous outflow was clearly recognized, was the tumor resected, together with the sinus without further flow restoration. A MEDLINE review of the literature published between 1955 and 2011 was performed.

Results. Long-term follow-up (mean 80 months) data obtained in 67 patients with meningiomas involving the SSS were analyzed. The recurrence rate was 10.4%; the morbidity and mortality rates were 10.4% and 4.5%, respectively. The authors identified in the literature 19 relevant studies on this issue, and based on their review of the literature, there is no evidence that aggressive management offers an advantage in terms of recurrence rate.

Conclusions. Analysis of the data obtained in the 67 patients confirmed good outcome and long-term tumor control following a surgical strategy aimed to preserve venous outflow. These findings and the results of the authors’ analysis of the literature emphasize that the goal of radical tumor resection should be balanced by an awareness of the increased surgical risk attendant on aggressive management of the SSS and bridging veins.

Endoscopic surgery for tuberculum sellae meningiomas: a systematic review and meta-analysis

TSM. EEA?

Neurosurg Rev (2013) 36:349–359

Recent reports of surgical resection of tuberculum sellae meningiomas through an endoscopic endonasal approach (EEA) have provided an alternative to transcranial approaches in selected cases. However, these published reports have been limited by small sample size from single institutions.We performed a systematic review and metaanalysis to gain insight into potential limitations and benefits of EEA for tuberculum sellae meningiomas.

We performed a systematic review of the literature and analyzed pooled data for descriptive statistics on short-term morbidity and outcomes. We compared EEA to transcranial approaches reported during the same time-frame. Six studies (49 patients) met inclusion criteria for EEA. A pooled analysis of transcranial results reported during a similar time period yielded 11 studies (412 patients).

There were no differences in rate of gross total resection or peri-operative complications between the two groups. Although the EEA group was associated with higher rates of CSF leak (p<0.05; OR 3.9; 95 % CI 1.15, 15.75), EEA were also associated with significantly higher rates of post-operative visual improvement compared to transcranial approaches (p<0.05; OR 1.5; 95 % CI 1.18, 1.82). A systematic review of the small series of EEA for tuberculum sellae meningiomas published to date revealed similar extent of resection and morbidity, but increased post-operative visual improvement compared to transcranial approaches during a similar time period.

Long-term follow-up will be needed to define recurrence rates of EEA as compared to transcranial approaches. Cautious use of EEA for the removal of smaller tuberculum sellae meningiomas after formal endoscopic training may be warranted.

Detecting the Offending Vessel in Hemifacial Spasm

Value of 3-Dimensional High-Resolution Magnetic Resonance Imaging in Detecting the Offending Vessel in Hemifacial Spasm

Neurosurgery 73:58–67, 2013

High-resolution 3-dimensional (3-D) magnetic resonance imaging (MRI) is widely used to predict the neurovascular anatomy within the cerebellopontine angle.

OBJECTIVE: To assess the value of 3-D steady-state free precession imaging (SSFP) and time-of-flight magnetic resonance angiography (TOF MRA) in detecting the offending vessels in hemifacial spasm in comparison to intraoperative endoscopic visualization.

METHODS: 42 patients underwent endoscope-assisted microvascular decompression (MVD). All available preoperative 3-D SSFP and TOF MRA images were checked. Intraoperative videos were captured by a high-definition endoscopic camera attached to endoscopes while exploring the area of facial nerve root exit zone (REZ). Evaluation of the 3-D images was performed by 2 independent groups of observers and compared with the operative findings.

RESULTS: Three-D MRI had an average positive predictive value (PPV) of 89.1% in differentiating between simple and complex compression. Mean accuracy of the images in detection of the offending vessels was 83.3% and 77% according to the first and second groups of observers, respectively. Averaged inter-observer agreement between the 2 groups of observers was substantial, with an averaged Kappa coefficient (K) of 0.56. In the simple compression group, mean accuracy was 97% and 89.4% according to the first and second groups of observers, respectively. Averaged K for agreement was substantial (K = 0.65).

CONCLUSION: According to endoscopic visualization, 3-D SSFP and TOF MRA images are accurate in detecting the offending vessels in simple compression of the facial nerve, and in predicting presence of a complex compression with variable sensitivity in identifying all offending vessels.

Modern surgical outcomes following surgery for sphenoid wing meningiomas

Sphenoid wing meningioma

J Neurosurg 119:86–93, 2013

Cushing and Eisenhardt were the first to describe sphenoid wing meningiomas in detail, categorizing globoid tumors into 3 groups: 1) medial; 2) middle; and 3) lateral. The authors review their experience with resection of sphenoid wing meningiomas at a single center, to examine whether this classification predicts clinical presentation and postsurgical outcome.

Methods. All patients undergoing resection of sphenoid wing meningioma at the authors’ institution over a 9-year period were identified. Clinical data were compared from patients with tumors arising at different points along the sphenoid wing to determine if these tumors behaved differently in terms of symptoms, radiographic characteristics, and postsurgical outcome.

Results. A total of 56 patients underwent microsurgical resection for sphenoid wing meningioma during this period. The rates of optic canal invasion (medial 50% vs middle 5% vs lateral 0%; p < 0.0001, chi-square test), supraclinoid internal carotid artery encasement (medial 32% vs middle 5% vs lateral 0%; p < 0.01, chi-square test), and middle cerebral artery encasement (medial 45% vs middle 24% vs lateral 0%; p < 0.01, chi-square test) were all highest with medial-third tumors. New or worsened neurological deficits occurred in 10 (19%) of 56 patients. Of all the imaging characteristics studied, only location of the tumor along the medial third of the sphenoid wing significantly predicted an increased rate of new or worsened neurological deficit (OR 2.7, p < 0.05).

Conclusions. The authors report outcomes in a large series of sphenoid wing meningiomas that were treated using modern surgical techniques.

The reliability of topographic measurements from navigated transcranial magnetic stimulation in healthy volunteers and tumor patients

nTCM stimulationreliability

Acta Neurochir (2013) 155:1309–1317

Navigated transcranial magnetic stimulation (nTMS) is increasingly being used for preoperative mapping of the motor cortex. Any new technology should undergo rigorous validation before being widely adopted in routine clinical practice.

The aim of this experimental study was to assess the intraexaminer and interexaminer reliability of topographic mapping with nTMS.

Methods nTMS mapping of the motor cortex for the first dorsal interosseous (FDI) muscle was performed by an expert and a novice examiner, twice in ten healthy volunteers and once in ten tumor patients. The distances between the centers-of-gravity and hotspots were calculated, as were coefficients of variation. This study also compared orthogonal versus variable orientation of the stimulation coil.

Results The mean (range) distance between centers-of-gravity for the expert examiner in the test–retest protocol with healthy volunteers was 4.40 (1.86–7.68)mm. The mean (range) distance between centers-of-gravity for the expert vs. novice examiner was 4.89 (2.39–9.22) mm. There were no significant differences in this result between healthy volunteers and tumor patients.

Conclusions nTMS is sufficiently reliable for clinical use, but examiners should make efforts to minimize sources of error. The reliability of nTMS in tumor patients appears comparable to healthy subjects.

Keywords

Intraoperative Seizures During Awake Craniotomy: Incidence and Consequences: Analysis of 477 Patients

Awake cranio

Neurosurgery 73:135–140, 2013

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 6 14 years vs 52 6 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 6 3.0 days vs 3.0 6 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.

Surgical treatment of thoracic disc disease via minimally invasive lateral transthoracic trans/retropleural approach

Surgical treatment of thoracic disc disease via minimally

Neurosurg Rev (2013) 36:455–465

Thoracic disc herniations are associated with serious neurological consequences if not treated appropriately. Although a number of techniques have been described, there is no consensus about the best surgical approach. In this study, the authors report their experience in the operative management of patients with thoracic disc herniations using minimally invasive lateral transthoracic trans/retropleural approach.

A series of 33 consecutive patients with thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through lateral approach is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed.

Forty disc levels in 33 patients (18F/15M; mean age, 52.9) were treated. Twenty-three patients presented with myelopathy (69 %), 31 had radiculopathy (94 %), and 31 had axial pain (94 %). Among patients with myelopathy, 14 (42.4 %) had bladder and/or bowel dysfunction. In the last eight cases (24 %), the approach was retropleural instead of transpleural. Patients were followed up for 18.2 months on average. The mean length of hospital stay was 5 days. None of the patients developed neurological deterioration postoperatively. Among 23 patients who had myelopathy signs, 21 (91 %) had improved postoperatively. The mean preoperative visual analog scale pain score, Oswestry Disability Index score, SF-36 PCS, and mental component summary scores were 7.5, 42.4, 29.6, and 37.5 which improved to 3.5, 33.2, 35.5, and 52.6, respectively. Perioperative complications occurred in six patients (18.1 %), all of which resolved uneventfully.

Minimally invasive lateral transthoracic trans/retropleural approach is a safe and efficacious technique for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional approaches.

Comparison of the accuracy of ventricular catheter placement using freehand placement, ultrasonic guidance, and stereotactic neuronavigation

Stereotactic Ventricular Catheter Placement

J Neurosurg 119:66–70, 2013

The objective of this study was to compare the accuracy of 3 methods of ventricular catheter placement during CSF shunt operations: the freehand technique using surface anatomy, ultrasonic guidance, and stereotactic neuronavigation.

Methods. This retrospective cohort study included all patients from a single institution who underwent a ventricular CSF shunting procedure in which a new ventricular catheter was placed between January 2005 and March 2010. Data abstracted for each patient included age, sex, diagnosis, method of ventricular catheter placement, site and side of ventricular catheter placement, Evans ratio, and bifrontal ventricular span. Postoperative radiographic studies were reviewed for accuracy of ventricular catheter placement. Medical records were also reviewed for evidence of shunt failure requiring revision through December 2011. Statistical analysis was then performed comparing the 3 methods of ventricular catheter placement and to determine risk factors for inaccurate placement.

Results. There were 249 patients included in the study; 170 ventricular catheters were freehand passed, 51 were placed using stereotactic neuronavigation, and 28 were placed under intraoperative ultrasonic guidance. There was a statistically significant difference between freehand catheters and stereotactic-guided catheters (p < 0.001), as well as between freehand catheters and ultrasound-guided catheters (p < 0.001). The only risk factor for inaccurate placement identified in this study was use of the freehand technique. The use of stereotactic neuronavigation and ultrasonic guidance reduced proximal shunt failure rates (p < 0.05) in comparison with a freehand technique.

Conclusions. Stereotactic- and ultrasound-guided ventricular catheter placements are significantly more accurate than freehand placement, and the use of these intraoperative guidance techniques reduced proximal shunt failure in this study.

Differences in the Basilar Artery Bifurcation Angle Among Patients Who Present With a Ruptured Aneurysm at the Top of the Basilar Artery and Patients With Perimesencephalic Subarachnoid Hemorrhage

Differences in the Basilar Artery Bifurcation Angle Among Patients Who Present With a Ruptured Aneurysm at the Top of the Basilar Artery and Patients With Perimesencephalic Subarachnoid Hemorrhage

Neurosurgery 73:2–7, 2013

The angle of the basilar artery bifurcation of (BAB angle) is thought to influence the risk of the development and rupture of aneurysms at this site. It is, however, unknown whether the BAB angle also influences the incidence of angiographically negative perimesencephalic subarachnoid hemorrhage (PMSAH).

OBJECTIVE: We performed a retrospective cross-sectional study comparing the BAB angle in a series of patients who presented with subarachnoid hemorrhage from a ruptured aneurysm at the top of the basilar artery (BSAH) with the BAB angle in a series of patients who presented with PMSAH.

METHODS: Consecutive patients who presented to our institution with PMSAH or BSAH between January 1, 2005 and December 31, 2010 were studied. Patients with PMSAH were further subdivided into patients with classic PMSAH (CPMSAH) and those with nonclassic PMSAH (NCPMSAH) based on initial head computed tomography examinations. In each patient, the BAB angle was measured on the standard cranial anteroposterior projections after vertebral artery injections.

RESULTS: A total of 21 patients with CPMSAH, 30 patients with NCPMSAH, and 31 patients with BSAH were studied. The BAB angle was significantly smaller in patients with CPMSAH (87.7 6 17.1 degrees) and NCPMSAH (98.4 6 21.1 degrees) compared with patients with BSAH (135.0 6 30.8 degrees) (P , .001).

CONCLUSION: The significantly lower BAB angle in PMSAH patients compared with BSAH patients suggests that bleeding in PMSAH is either nonarterial in nature or is secondary to variations in hemodynamic arterial stress at the top of the basilar artery that need to be studied further with computational models.

Surgical treatment of tentorial dural arteriovenous fistulae located around the tentorial incisura

Surgical treatment of tentorial dural arteriovenous fistulae

Neurosurg Rev (2013) 36:429–435

Tentorial dural arteriovenous fistulae (DAVF) are relatively uncommon and are the most dangerous type of DAVF. Because of a high incidence of hemorrhage and subsequent neurological deficits, treatment is mandatory.

A consecutive series of nine surgically treated patients with symptomatic tentorial DAVF were analyzed in this study. All lesions were located around the tentorial incisura and were treated microsurgically using a subtemporal approach in eight cases and a supracerebellar approach in one case. The dural bases of the lesions were located adjacent to the tentorial edge in six patients and the tentorial apex in three patients.

Complete obliteration was achieved in all treated tentorial DAVF. In one patient, the torcular fistula remained untreated without cortical venous reflux. Postoperative asymptomatic temporal lobe hemorrhage was diagnosed in one patient with a tentorial apex DAVF; however, no new neurological symptoms were present after surgical treatment.

The subtemporal approach for unilateral tentorial DAVF is a favorable and direct approach for the highly skilled surgeon. Perimesencephalic venous dilatation or varix is an important finding onMRI to help localize tentorial DAVF in the tentorial edge or apex.