Author: cba

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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.

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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.

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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.

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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.

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Deep Brain Stimulation in DYT1 Dystonia: A 10-Year Experience

Electrode-Implantation-for-Deep-Brain-Stimulation-small1

Neurosurgery 73:86–93, 2013

Globus Pallidus Interna (GPi) deep brain stimulation (DBS) is an effective treatment for DYT1-associated dystonia, but long-term results are lacking.

OBJECTIVE: To evaluate the long-term effects of GPi DBS in patients with DYT1 dystonia.

METHODS: A retrospective chart review (cohort study) of 47 consecutive DYT11 patients treated by a single surgical team over a 10-year period and followed for up to 96 months (mean, 46 months) was performed. Symptom severity was quantified with the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor (M) and disability (D) sub-scores.

RESULTS: As measured with the BFMDRS (M), symptom severity was reduced to less than 20% of baseline after 2 years of DBS therapy (P = .001). The disability scores were reduced to ,30% of baseline (P = .001). Symptomatic improvement was durable throughout available follow-up. Sixty-one percent of patients had discontinued all dystonia-related medications at their last follow-up. Ninety-one percent had discontinued at least 1 class of medication. Infections requiring removal and later reimplantation of hardware occurred in 4 of 47 patients (8.5%). Hardware malfunction including lead fractures occurred in 4 of 47 cases (8.5%). Lead revision to address poor clinical response was performed in 2 of 92 implanted leads (2.2%).

CONCLUSION: GPi DBS is an effective therapy for DYT1-associated torsion dystonia. Statistically significant efficacy is maintained for up to 7 years. Neurologic complications are rare, but long-term hardware-related complications can be significant.

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The Barrow Ruptured Aneurysm Trial: 3-year results

aneurysm-300x204

J Neurosurg 119:146–157, 2013

The authors report the 3-year results of the Barrow Ruptured Aneurysm Trial (BRAT). The objective of this ongoing randomized trial is to compare the safety and efficacy of microsurgical clip occlusion and endovascular coil embolization for the treatment of acutely ruptured cerebral aneurysms and to compare functional outcomes based on clinical and angiographic data. The 1-year results have been previously reported.

Methods. Two-hundred thirty-eight patients were assigned to clip occlusion and 233 to coil embolization. There were no anatomical exclusions. Crossovers were allowed based on the treating physician’s determination, but primary outcome analysis was based on the initial assignment to treatment modality. Patient outcomes were assessed independently using the modified Rankin Scale (mRS). A poor outcome was defined as an mRS score > 2. At 3 years’ follow-up 349 patients who had actually undergone treatment were available for evaluation. Of the 170 patients who had been originally assigned to coiling, 64 (38%) crossed over to clipping, whereas 4 (2%) of 179 patients assigned to surgery crossed over to clipping.

Results. The risk of a poor outcome in patients assigned to clipping compared with those assigned to coiling (35.8% vs 30%) had decreased from that observed at 1 year and was no longer significant (OR 1.30, 95% CI 0.83–2.04, p = 0.25). In addition, the degree of aneurysm obliteration (p = 0.0001), rate of aneurysm recurrence (p = 0.01), and rate of retreatment (p = 0.01) were significantly better in the group treated with clipping compared with the group treated with coiling. When outcomes were analyzed based on aneurysm location (anterior circulation, n = 339; posterior circulation, n = 69), there was no significant difference in the outcomes of anterior circulation aneurysms between the 2 assigned groups across time points (at discharge, 6 months, 1 year, or 3 years after treatment). The outcomes of posterior circulation aneurysms were significantly better in the coil group than in the clip group after the 1st year of follow-up, and this difference persisted after 3 years of follow-up. However, while aneurysms in the anterior circulation were well matched in their anatomical location between the 2 treatment arms, this was not the case in the posterior circulation where, for example, 18 of 21 posterior inferior cerebellar artery aneurysms were in the clip group.

Conclusions. Based on mRS scores at 3 years, the outcomes of all patients assigned to coil embolization showed a favorable 5.8% absolute difference compared with outcomes of those assigned to clip occlusion, although this difference did not reach statistical significance (p = 0.25). Patients in the clip group had a significantly higher degree of aneurysm obliteration and a significantly lower rate of recurrence and retreatment. In post hoc analysis examining only anterior circulation aneurysms, no outcome difference between the 2 treatment cohorts was observed at any recorded time point. Clinical trial registration no.: NCT01593267 (ClinicalTrials.gov).

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Blood-based biomarkers for malignant gliomas

Blood-based biomarkers for malignant gliomas

J Neurooncol (2013) 113:345–352

Malignant gliomas remain incurable and present unique challenges to clinicians, radiologists and clinical and translational investigators. One of the major problems in treatment of these tumors is our limited ability to reliably assess tumor response or progression.

The most frequently used neuro-imaging studies (contrast-enhanced MRI and CT) rely on changes of blood–brain barrier (BBB) integrity, providing only an indirect assessment of tumor burden. In addition, the BBB can be altered by commonly used interventions including radiation, glucocorticoids and vascular endothelial growth factor inhibitors, further complicating the interpretation of scans. Newer radiologic techniques including PET and magnetic resonance spectroscopy are theoretically promising but thus far have not meaningfully changed the assessment of patients with malignant gliomas. A tumor-specific, bloodbased biomarker would be of immediate use to clinicians and investigators if sufficiently sensitive and specific.

This review discusses the potential utility of such a biomarker, the general classes of tumor-derived blood-based biomarkers and it summarizes the currently available data on circulating tumor cells, circulating nucleic acids and circulating proteins in patients with malignant gliomas. It is unclear which marker or marker class appears to be the most promising for these tumors.

This article provides thoughts on how novel candidate blood-based markers could be discovered and tested in a more comprehensive way and why these efforts should be among the top priorities in neuro-oncologic research in the coming years.

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Intraoperative fluorescence for resection of hemangioblastomas

Intraoperative fluorescence for resection of hemangioblastomas

Acta Neurochir (2013) 155:1287–1292

Resection of hemangioblastomas can be challenging due to their high vascularity and intimate association with neighboring cerebrovascular structures. The authors present their intraoperative findings using fluorescein angiography and fluorescence for removal of hemangioblastomas in an attempt to improve the safety and extent of resection.

Methods From April through August 2012, four patients were diagnosed with hemangioblastomas, 3 in the cerebellum and 1 in the medulla oblongata. Low-dose (4 mg/kg) sodium fluorescein was injected intravenously immediately before microdissection. The area of interest was inspected through a microscope-integrated fluorescent module.

Results In three superficially located tumors, the vascular pattern of feeding and draining vessels could be easily identified with fluorescein angiography. The resection of the tumors was guided using real-time fluorescence mode. For each patient, histopathologic examination of the lesion confirmed the diagnosis of hemangioblastoma. All samples of fluorescent tissue resected were confirmed to contain tumor. No patient experienced any complication.

Conclusion Low-dose sodium fluorescein used in conjunction with a microscope-integrated fluorescence module is a potentially useful tool for localization, vascular characterization, and resection of hemangioblastomas.

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Risk factor analysis of the development of new neurological deficits following supplementary motor area resection

Supplementary motor area

J Neurosurg 119:7–14, 2013

Supplementary motor area (SMA) resection often induces postoperative contralateral hemiparesis or speech disturbance. This study was performed to assess the neurological impairments that often follow SMA resection and to assess the risk factors associated with these postoperative deficits.

Methods. The records for patients who had undergone SMA resection for pharmacologically intractable epilepsy between 1994 and 2010 were gleaned from an epilepsy surgery database and retrospectively reviewed in this study.

Results. Forty-three patients with pharmacologically intractable epilepsy underwent SMA resection with intraoperative cortical stimulation and mapping while under awake anesthesia. The mean patient age was 31.7 years (range 15–63 years), and the mean duration and frequency of seizures were 10.4 years (range 0.1–30 years) and 14.6 per month (range 0.1–150 per month), respectively. Pathological examination of the brain revealed cortical dysplasia in 18 patients (41.9%), tumors in 16 patients (37.2%), and other lesions in 9 patients (20.9%). The mean duration of the follow-up period was 84.0 months (range 24–169 months). After SMA resection, 23 patients (53.5%) experienced neurological deficits. Three patients (7.0%) experienced permanent deficits, and 20 (46.5%) experienced symptoms that were transient. All permanent deficits involved contralateral weakness, whereas the transient symptoms patients experienced were varied, including contralateral weaknesses in 15, apraxia in 1, sensory disturbances in 1, and dysphasia in 6. Thirteen patients recovered completely within 1 month. Univariate analysis revealed that resection of the SMA proper, a shorter lifetime seizure history (< 10 years), and resection of the cingulate gyrus in addition to the SMA were associated with the development of neurological deficits (p = 0.078, 0.069, and 0.023, respectively). Cingulate gyrus resection was the only risk factor identified on multivariate analysis (p = 0.027, OR 6.530, 95% CI 1.234–34.562).

Conclusions. Resection of the cingulate gyrus in addition to the SMA was significantly associated with the development of postoperative neurological impairment.

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Early seizures after clipping of unruptured aneurysms of the anterior circulation

Early seizures after clipping of unruptured aneurysms

Neurosurg Rev (2013) 36:447–454

Seizures occurring after clipping of unruptured cerebral aneurysms have rarely been documented in the literature. The objective of this retrospective study is to clarify whether the frequency of early seizures, i.e., seizures occurring within 14 days of surgery, is influenced by patient- or aneurysm-specific characteristics.

Data on 1,000 consecutive patients who underwent clipping of unruptured anterior circulation aneurysms were reviewed. They consisted of 387 men and 613 women with mean age of 59.8±9.7 years. Fifty-one patients (5.1 %) developed early seizures. Interestingly, the frequency was similar to that occurring after clipping of unruptured posterior circulation aneurysms (n=20, 5.0 %). Multivariate regression analysis revealed that younger age was correlated with early seizures (odds ratio (OR) 0.902; 95 % confidence interval (CI) 0.891–0.989). However, other variables, including aneurysm size and operation length, were not correlated. Although patients with history of epilepsy exhibited relatively high frequency of early seizures, the difference was not statistically significant.

The frequency was unaffected by location or multiplicity of aneurysms. Thirty-one patients (61 %) developed seizures within 24 h of clipping. Regarding seizure types, 34 (67 %) developed generalized seizures and the other 17 (33 %) experienced partial seizures. Patients with generalized seizures were significantly more likely to harbor an iatrogenic brain lesion than those with partial seizures (47 vs. 18 %; OR 4.148; 95 % CI 1.005–17.113). Among 40 patients with follow-up period >12 months, seizures were temporary without recurrence in 38 (95 %).

Although early seizures are mostly benign, a small possibility of them becoming a permanent morbidity needs to be explained to patients undergoing elective clipping.

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Interactive presurgical simulation applying 3D techniques

3D CG data and the color-printed plaster model for a left tentorial meningioma

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.

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Impact of anterior clinoidectomy on visual function after resection of meningiomas in and around the optic canal

Clinoidectomy

Acta Neurochir (2013) 155:1293–1299

Meningiomas of the anterior and middle skull base frequently involve the optic nerve and cause progressive visual impairment. Surgical decompression of the optic nerve is the only option to preserve visual function. Depending on the invaded structures, optic nerve decompression can be part of a complete tumor removal or the main surgical intention in terms of local debulking. However, bony decompression of the optic canal including anterior clinoidectomy for optic nerve decompression is still a surgical maneuver under discussion.

Methods From 2006 to 2011, 46 consecutive patients with skull base meningiomas in and around the optic canal were operated. The pterional approachwas tailored for each patient. Resection included bony decompression of the optic canal with or without anterior clinoidectomy. Visual acuity and fields were evaluated pre- and postoperatively.

Results Fifty-three percent of patients underwent anterior clinoidectomy, 23 % optic canal unroofing, and 24 % any bony decompression. In 21 patients (46 %), gross total resection (GTR, Simpson grade I or II) was achieved, while 25 patients (54 %) received subtotal resection (STR, Simpson grade III or IV). Sixty-three percent of patients presented with preoperative visual impairment. Postoperative visual changes were significantly related to preoperative visual function. While all patients with normal preoperative vision remained unchanged, in patients with impaired vision, surgery caused improvement in 70%and deterioration in 10 % of patients (p<0.0001). In patients with anterior clinoidectomy, vision improved more frequently than without anterior clinoidectomy (p<0.05).

Conclusions Anterior clinoidectomy is safe and may improve visual outcome in meningiomas in and around the optic canal.

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A New, More Accurate Classification of Middle Cerebral Artery Aneurysms

MCAA class

Neurosurgery 73:94–102, 2013

Classification of middle cerebral artery (MCA) aneurysms is sometimes difficult because the identification of the main MCA bifurcation, the key for accurate classification of MCA aneurysms, is inconsistent and somewhat subjective.

OBJECTIVE: To use the meeting point of the M1 and M2 trunks as an objective, generally accepted, and angiographically evident hallmark for identification of MCA bifurcation and more accurate classification of MCA aneurysms.

METHODS: We reviewed the computed tomographic angiography data of 1009 consecutive patients with 1309 MCA aneurysms. The M2 trunks were followed proximally until their meeting with the M1 trunk at the main MCA bifurcation. The aneurysms were classified according to their relative location: proximal, at, or distal to the MCA bifurcation. The M1 aneurysms were further subgrouped into M1 early cortical branch aneurysms and M1 lenticulostriate artery aneurysms, extending the classic 3-group classification of MCA aneurysms into a 4-group classification.

RESULTS: The main MCA bifurcation was the most common location for MCA aneurysms, harboring 829 aneurysms (63%). The 406 M1 aneurysms comprised 242 M1 early cortical branch aneurysms (60%) and 164 M1 lenticulostriate artery aneurysms (40%). We found 106 MCA aneurysms (8%) at the origin of large early frontal branches simulating M2 trunks liable to be misclassified as MCA bifurcation aneurysms. Even though 51% of the 407 ruptured MCA aneurysms were associated with an intracerebral hematoma, this did not affect the classification.

CONCLUSION: Studying MCA angioarchitecture and applying the 4-group classification of MCA aneurysms is practical and facilitates the accurate classification of MCA aneurysms, helping to improve surgical outcome.

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