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Fractional anisotropy in patients with disproportionately enlarged subarachnoid space hydrocephalus

Fractional anisotropy in patients with disproportionately enlarged subarachnoid space hydrocephalus

Acta Neurochir (2016) 158:1495–1500

Disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings on MRI were described as a prognostic factor for responsiveness to the treatment of idiopathic normal pressure hydrocephalus (iNPH). Our premise is that DESH could be associated with compression of the cerebral white matter. Microstructural changes can be identified using diffusion tensor imaging (DTI), specifically fractional anisotropy (FA). The aim of this study is to compare FA in iNPH patients with and without DESH and healthy controls.

Methods: We analysed 1.5-T MRI scans of patients fulfilling the criteria of probable or possible iNPH and positive supplementary tests before and after surgery (ventriculo-peritoneal shunt). FA was measured in the anterior and posterior limb of the internal capsule (PLIC) and in the corpus callosum. Patients were divided into the DESH and non-DESH group. These data were also compared to FA values in the control group.

Results: Twenty-seven patients and 24 healthy controls were enrolled. DESH was present in 15 patients and lacking in 12. Twenty-three iNPH patients were shunt responders (85.2 %), and 4 were non-responders (14.8 %). All patients in the DESH group were shunt responders. In the non-DESH group, eight patients were responders (66.7 %). A significant difference between the DESH and non-DESH group was found in the FA of the PLIC. The mean value of FA in the PLIC was 0.72 in the DESH group and 0.66 in the non-DESH group. After the surgery FA decreased in both groups. In the DESH iNPH group FA PLIC decreased to 0.65 and in the non-DESH iNPH group to 0.60. In the healthy controls, the mean FA in the PLIC was 0.58.

Conclusion: DESH on MRI scans is related to a higher FA in the PLIC with a decrease after the surgery. It reflects a more severe compression of the white matter than in non-DESH patients or healthy volunteers. DESH patients had better outcome than non-DESH patients. This study confirmed the importance of DESH as a supportive sign for iNPH.

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The Risk of Seizure After Surgery for Unruptured Intracranial Aneurysms

Incidence of growth and rupture of unruptured intracranial aneurysms followed by serial MRA

Neurosurgery 79:222–230, 2016

We aimed to identify a group of patients with a low risk of seizure after surgery for unruptured intracranial aneurysms (UIA).

OBJECTIVE: To determine the risk of seizure after discharge from surgery for UIA.

METHODS: A consecutive prospectively collected cohort database was interrogated for all surgical UIA cases. There were 726 cases of UIA (excluding cases proximal to the superior cerebellar artery on the vertebrobasilar system) identified and analyzed. Cox proportional hazards regression models and Kaplan-Meier life table analyses were generated assessing risk factors.

RESULTS: Preoperative seizure history and complication of aneurysm repair were the only risk factors found to be significant. The risk of first seizure after discharge from hospital following surgery for patients with neither preoperative seizure, treated middle cerebral artery aneurysm, nor postoperative complications (leading to a modified Rankin Scale score .1) was ,0.1% and 1.1% at 12 months and 7 years, respectively. The risk for those with preoperative seizures was 17.3% and 66% at 12 months and 7 years, respectively. The risk for seizures with either complications (leading to a modified Rankin Scale score .1) from surgery or treated middle cerebral artery aneurysm was 1.4% and 6.8% at 12 months and 7 years, respectively. These differences in the 3 Kaplan-Meier curves were significant (log-rank P , .001).

CONCLUSION: The risk of seizures after discharge from hospital following surgery for UIA is very low when there is no preexisting history of seizures. If this result can be supported by other series, guidelines that restrict returning to driving because of the risk of postoperative seizures should be reconsidered.

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Defining a Standardized Approach for the Bedside Insertion of Temporal Horn External Ventricular Drains

Standardized Approach for the Bedside Insertion of Temporal Horn External Ventricular Drains

Neurosurgery 79:296–304, 2016

A trapped temporal horn can be emergently decompressed by inserting a bedside temporal horn external ventricular drain (tEVD). However, no standardized method for this procedure has been described.

OBJECTIVE: To identify methods for bedside tEVD insertion, and determine the safest, most accurate, and most easily standardized approach.

METHODS: Volumetric images of 20 patients with trapped temporal horns were analyzed. Three tEVD approaches (perpendicular, lateral, and medial) were defined, along with standardized insertion points and external landmarks for trajectory guidance. Predicted success in penetrating the temporal horn, skin-to-temporal horn entrance distance, temporal horn distance traversed, and trajectory target error and accuracy were evaluated; data were compared with independent sample t tests.

RESULTS: Nineteen of 20 cases were analyzed; 13 had critical temporal horn entrapment. Penetration was achieved in 100% of perpendicular and 84% (16/19) of lateral and medial approaches (92% [12/13] of critical entrapments). In 19 patients, trajectory error was not significantly different among approaches. The perpendicular approach had significantly more accuracy than the lateral (P = .01) and medial (P = .002) approaches. The lateral approach afforded significantly more traversable distance than the perpendicular approach (P = .009). In cases with critical entrapment, the perpendicular approach had significantly less error (P = .02) and significantly better accuracy (P = .02) than the medial approach. The perpendicular approach trended toward more accuracy than the lateral approach (P = .06).

CONCLUSION: The perpendicular approach appears to be the easiest, safest, and most reliable approach tested. We recommend conducting bedside tEVD placement only in patients with a critically dilated temporal horn who are clinically deteriorating at a rate that prohibits other procedures.

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Improved Function After Deep Brain Stimulation for Chronic, Severe Traumatic Brain Injury

Improved Function After Deep Brain Stimulation for Chronic, Severe Traumatic Brain Injury

Neurosurgery 79:204–211, 2016

Severe traumatic brain injury (TBI) damages the frontal lobes and connecting networks, which impairs executive functions, including the ability to selfregulate. Despite significant disabling effects, there are few treatment options in the chronic phase after injury.

OBJECTIVE: To investigate the safety and potential effectiveness of deep brain stimulation (DBS) for individuals with chronic, disabling TBI and problems of behavioral and emotional self-regulation.

METHODS: This study was an open-label, prospective design with serial assessments of behavioral outcomes and positron emission tomography 2 years after DBS implantation. Four participants 6 to 21 years after severe TBIs from automobile crashes were included. Although alert and volitional, all experienced significant executive impairments, including either impulsivity or reduced initiation. DBS implants were placed bilaterally in the nucleus accumbens and anterior limb of the internal capsule to modulate the prefrontal cortex.

RESULTS: The procedure was safe, and all participants had improved functional outcomes. Two years after implantation, 3 met a priori criteria for improvement on the Mayo-Portland Adaptability Inventory-4. Improvement was due largely to better emotional adjustment, although 1 participant showed marked increases in multiple domains. Significant improvement in a composite score of functional capacity indicated improved independence in self-care and activities of daily living. The pattern of change in cognition corresponded with changes in activation of the prefrontal cortex observed in serial scanning.

CONCLUSION: This first study of DBS to this target for severe TBI supports its safety and suggests potential effectiveness to improve function years after injury. The primary impact was on behavioral and emotional adjustment, which in turn improved functional independence.

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How to predict return to work after lumbar discectomy

How to predict return to work after lumbar discectomy- answers from the NeuroPoint-SD registry

J Neurosurg Spine 25:181–186, 2016

To date, the factors that predict whether a patient returns to work after lumbar discectomy are poorly understood. Information on postoperative work status is important in analyzing the cost-effectiveness of the procedure.

Methods An observational prospective cohort study was completed at 13 academic and community sites (Neuro- Point–Spinal Disorders [NeuroPoint-SD] registry). Patients undergoing single-level lumbar discectomy were included. Variables assessed included age, sex, body mass index (BMI), SF-36 physical function score, Oswestry Disability Index (ODI) score, presence of diabetes, smoking status, systemic illness, workers’ compensation status, and preoperative work status. The primary outcome was working status within 3 months after surgery. Stepwise logistic regression analysis was performed to determine which factors were predictive of return to work at 3 months following discectomy.

Results There were 127 patients (of 148 total) with data collected 3 months postoperatively. The patients’ average age at the time of surgery was 46 ± 1 years, and 66.9% of patients were working 3 months postoperatively. Statistical analyses demonstrated that the patients more likely to return to work were those of younger age (44.5 years vs 50.5 years, p = 0.008), males (55.3% vs 28.6%, p = 0.005), those with higher preoperative SF-36 physical function scores (44.0 vs 30.3, p = 0.002), those with lower preoperative ODI scores (43.8 vs 52.6, p = 0.01), nonsmokers (83.5% vs 66.7%, p = 0.03), and those who were working preoperatively (91.8% vs 26.2%, p < 0.0001). When controlling for patients who were working preoperatively (105 patients), only age was a statistically significant predictor of postoperative return to work (44.1 years vs 51.1 years, p = 0.049).

Conclusions In this cohort of lumbar discectomy patients, preoperative working status was the strongest predictor of postoperative working status 3 months after surgery. Younger age was also a predictor. Factors not influencing return to work in the logistic regression analysis included sex, BMI, SF-36 physical function score, ODI score, presence of diabetes, smoking status, and systemic illness. Clinical trial registration no.: 01220921 (clinicaltrials.gov).

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First Human Implantation of a Bioresorbable Polymer Scaffold for Acute Traumatic Spinal Cord Injury

First Human Implantation of a Bioresorbable Polymer Scaffold for Acute Traumatic Spinal Cord Injury

Neurosurgery 79:E305–E312, 2016

A porous bioresorbable polymer scaffold has previously been tested in preclinical animal models of spinal cord contusion injury to promote appositional healing, spare white matter, decrease posttraumatic cysts, and normalize intraparenchymal tissue pressure. This is the first report of its human implantation in a spinal cord injury patient during a pilot study testing the safety and feasibility of this technique (ClinicalTrials.gov Identifier: NCT02138110).

CLINICAL PRESENTATION: A 25-year-old man had a T11-12 fracture dislocation sustained in a motocross accident that resulted in a T11 American Spinal Injury Association Impairment Scale (AIS) grade A traumatic spinal cord injury. He was treated with acute surgical decompression and spinal fixation with fusion, and enrolled in the spinal scaffold study. A 2 x 10 mm bioresorbable scaffold was placed in the spinal cord parenchyma at T12. The scaffold was implanted directly into the traumatic cavity within the spinal cord through a dorsal root entry zone myelotomy at the caudal extent of the contused area. By 3 months, his neurological examination improved to an L1 AIS grade C incomplete injury. At 6-month postoperative follow-up, there were no procedural complications or apparent safety issues related to the scaffold implantation.

CONCLUSION: Although longer-term follow-up and investigation are required, this case demonstrates that a polymer scaffold can be safely implanted into an acutely contused spinal cord. This is the first human surgical implantation, and future outcomes of other patients in this clinical trial will better elucidate the safety and possible efficacy profile of the scaffold.

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Fewer complications with bolt-connected than tunneled external ventricular drainage

evd_catheter_3001401_1_m

Acta Neurochir (2016) 158:1491–1494

Ventriculostomy/external ventricular drain (EVD) is a common neurosurgical procedure. Various techniques are used to fixate the drain and the objective of this study was, in a retrospective setting, to compare the incidence of complications when using bolt-connected EVD (BC-EVD) versus tunneled EVD (T-EVD).

Methods All patients subjected to an EVD performed through a new burr hole from 2009 through 2010 at two Depts. of Neurosurgery in Denmark (Odense and Aarhus) were retrospectively identified. Patient files were evaluated for EVD fixation technique (tunneled or bolt-connected EVD) and complications including unintended removal, catheter obstruction, infection, CSF leakage, and mechanical problems.

Results A total of 271 patients with 272 separate EVDs met the inclusion criteria. There was a statistically higher rate of complications leading to reinsertion in the tunneled EVD group (40 %), compared to the bolt-connected EVD group (6.5 %). There was no significant difference in infection rates.

Conclusions Tunneled EVD has a relatively high frequency of complications leading to reinsertion. The use of Bolt-connected EVD technique can lower this frequency significantly. The number needed to treat is three for preventing a complication requiring reinsertion. Infection rates are low for both types of ventriculostomies. Accordingly, we recommend use of Bolt-connected EVDs in neurosurgical practice.

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Resting-state functional MRI in an intraoperative MRI setting

Resting-state functional MRI in an intraoperative MRI setting-1

J Neurosurg 125:401–409, 2016

The authors’ aim in this paper is to prove the feasibility of resting-state (RS) functional MRI (fMRI) in an intraoperative setting (iRS-fMRI) and to correlate findings with the clinical condition of patients pre- and postoperatively.

Methods: Twelve patients underwent intraoperative MRI-guided resection of lesions in or directly adjacent to the central region and/or pyramidal tract. Intraoperative RS (iRS)–fMRI was performed pre- and intraoperatively and was correlated with patients’ postoperative clinical condition, as well as with intraoperative monitoring results. Independent component analysis (ICA) was used to postprocess the RS-fMRI data concerning the sensorimotor networks, and the mean z-scores were statistically analyzed.

Results: iRS-fMRI in anesthetized patients proved to be feasible and analysis revealed no significant differences in preoperative z-scores between the sensorimotor areas ipsi- and contralateral to the tumor. A significant decrease in z-score (p < 0.01) was seen in patients with new neurological deficits postoperatively. The intraoperative z-score in the hemisphere ipsilateral to the tumor had a significant negative correlation with the degree of paresis immediately after the operation (r = -0.67, p < 0.001) and on the day of discharge from the hospital (r = -0.65, p < 0.001). Receiver operating characteristic curve analysis demonstrated moderate prognostic value of the intraoperative z-score (area under the curve 0.84) for the paresis score at patient discharge.

Conclusions: The use of iRS-fMRI with ICA-based postprocessing and functional activity mapping is feasible and the results may correlate with clinical parameters, demonstrating a significant negative correlation between the intensity of the iRS-fMRI signal and the postoperative neurological changes.

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Supratentorial hemispheric ependymomas: an analysis of 109 adults for survival and prognostic factors

supratentorial hemispheric ependymomas

J Neurosurg 125:410–418, 2016

Survival rates and prognostic factors for supratentorial hemispheric ependymomas have not been determined. The authors therefore designed a retrospective study to determine progression-free survival (PFS), overall sur- vival (OS), and prognostic factors for hemispheric ependymomas.

Methods: The study population consisted of 8 patients from our institution and 101 patients from the literature with disaggregated survival information (n = 109). Patient age, sex, tumor side, tumor location, extent of resection (EOR), tumor grade, postoperative chemotherapy, radiation, time to recurrence, and survival were recorded. Kaplan-Meier survival analyses and Cox proportional hazard models were completed to determine survival rates and prognostic factors.

Results: Anaplastic histology/WHO Grade III tumors were identifed in 62% of cases and correlated with older age. Three-, 5-, and 10-year PFS rates were 57%, 51%, and 42%, respectively. Three-, 5-, and 10-year OS rates were 77%, 71%, and 58%, respectively. EOR and tumor grade were identifed on both Kaplan-Meier log-rank testing and univariate Cox proportional hazard models as prognostic for PFS and OS. Both EOR and tumor grade remained prognostic on multivariate analysis. Subtotal resection (STR) predicted a worse PFS (hazard ratio [HR] 4.764, p = 0.001) and OS (HR 4.216, p = 0.008). Subgroup survival analysis of patients with STR demonstrated a 5- and 10-year OS of 28% and 0%, respectively. WHO Grade III tumors also had worse PFS (HR 10.2, p = 0.004) and OS (HR 9.1, p = 0.035). Patients with WHO Grade III tumors demonstrated 5- and 10-year OS of 61% and 46%, respectively. Postoperative radiation was not prognostic for PFS or OS.

Conclusions: A high incidence of anaplastic histology was found in hemispheric ependymomas and was associated with older age. EOR and tumor grade were prognostic factors for PFS and OS on multivariate analysis. STR or WHO Grade III pathology, or both, predicted worse overall prognosis in patients with hemispheric ependymoma.

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Routine early CT scanning after craniotomy: is it effective for the early detection of postoperative intracranial hematoma?

postoperative intracranial hematoma

Acta Neurochir (2016) 158:1447–1452

Postoperative intracranial hematoma (POIH) is a frequent sequela secondary to cranial surgery. The role of routine early postoperative computed tomography (CT) scanning in the detection of POIH remains controversial. The study was aimed at analyzing the effect of routine early CT scanning after craniotomy for the early detection of POIH.

Methods Routine early postoperative CT scanning was performed at our institute, and a retrospective study was conducted to analyze the data. POIH was defined as an intra- cranial hematoma requiring surgical management.

Results A total of 1,148 patients undergoing craniotomy were included in this study; 28 of these patients developed POIH. The majority of POIH cases (15/28, 54 %) were detected during the first 6 h following craniotomy. A routine CT scan was per- formed on all included patients but two; however, CT scans detected only 16 POIH cases. During the first 6 h, the rate at which CT scans detected POIH was 1.9 % (15/786); subse- quently, the rate decreased to only 0.3 % (1/360; p<0.05, compared with the rate during the first 6h). Among patients without clinical manifestations, the rate at which the routine post-craniotomy CT scan detected POIH was only 0.7 % (5/721) (p<0.05, compared with the incidence of POIH). Finally, among high-risk POIH patients, the POIH-positive rate of routine CT scanning was elevated.

Conclusions It appears that routine early CT scan is ineffective for the detection of POIH in patients undergoing craniotomy. However, if the strategy for routine scanning can be improved, its effect may be beneficial.

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Three-Year Follow-up of the Prospective, Randomized, Controlled Trial of Coflex Interlaminar Stabilization vs Instrumented Fusion in Patients With Lumbar Stenosis

Three-Year Follow-up of the Prospective, Randomized, Controlled Trial of Coflex Interlaminar Stabilization vs Instrumented Fusion in Patients With Lumbar Stenosis

Neurosurgery 79:169–181, 2016

Traditional surgical options for the treatment of symptomatic lumbar spinal stenosis include decompression alone vs decompression and fusion; both options have potential limitations.

OBJECTIVE: To report the 36-month follow-up analysis of the coflex Interlaminar Stabilization (Paradigm Spine, LLC, New York, New York) after decompression, examined under a Food and Drug Administration investigational device exemption clinical trial, which is intended to provide stabilization after decompression while preserving normal segmental motion at the treated level.

METHODS: The coflex trial was a prospective, randomized investigational device exemption study conducted at 21 clinical sites in the United States. Baseline and followup visits collected demographics, clinical, and radiographic status. The primary endpoint was a measure of composite clinical success 24 months postoperatively. For this current 36-month analysis, composite clinical success was calculated using analogous methods.

RESULTS: Composite clinical success at 36 months was achieved by 62.2% among 196 coflex Interlaminar Stabilization patients and 48.9% among 94 fusion patients (difference = 13.3%, 95% confidence interval, 1.1%-25.5%, P = .03). Bayesian posterior probabilities for noninferiority (margin = 210%) and superiority of cofle Interlaminar Stabilization vs fusion were .0.999 and 0.984, respectively. Substantial and comparable improvements were observed in both groups for patient-reported outcomes, although the percentage with a clinically significant improvement ($15) in the Oswestry Disability Index seemed larger for the coflex Interlaminar Stabilization group relative to the fusion group (P = .008). Radiographic measurements maintained index level and adjacent level range of motion in coflex Interlaminar Stabilization patients, although range of motion at the level superior to fusion was significantly increased (P = .005).

CONCLUSION: Coflex Interlaminar Stabilization for stenosis is proven to be effective and durable at improving overall composite clinical success without altering normal spinal kinematic motion at the index level of decompression or adjacent levels.

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Long-term Outcomes of Patients With Giant Intracranial Arteriovenous Malformations

giant AVM

Neurosurgery 79:116–124, 2016

Giant intracranial arteriovenous malformations (AVMs) are rare cerebrovascular lesions that pose management challenges.

OBJECTIVE: To further clarify outcomes in patients with giant cerebral AVMs managed with conservative or interventional therapies.

METHODS: We performed a retrospective review of all patients diagnosed with AVMs evaluated at our institution from 1990 to 2013. Patients with a single intracranial AVM .6 cm were included. Patients were divided into 2 groups: conservative management or intervention (microsurgery, radiosurgery, or embolization). Functional outcome was assessed with the modified Rankin Scale (mRS) and compared between the 2 groups.

RESULTS: A total of 55 patients with giant AVMs were included, and 35 patients (63.6%) had clinical follow-up with a mean of 11.8 years. Spetzler-Martin grades were as follows: grade III, n = 2 (3.6%); grade IV, n = 15 (27.3%); and grade V, n = 38 (69.1%). Twenty-four patients (43.6%) were conservatively managed. The patients in the conservatively managed group had larger AVMs (P , .05) with more frequent involvement of the temporal lobe (P = .02). Five patients (26.3%) in the conservatively managed group and 5 (31.3%) in the intervention group experienced hemorrhage during follow-up, translating to an annualized risk of 2.7% and 4.1%, respectively. No significant difference in risk of first subsequent hemorrhage was observed (P = .78). Despite comparable mRS scores at presentation, we observed a trend toward better outcomes (mRS , 2) in patients undergoing conservative management (P = .06) compared with the intervention group at last follow-up.

CONCLUSION: This study suggests that interventions for giant AVMs should be considered cautiously because hemorrhagic risk is similar regardless of management strategy and functional outcome is likely to be same or better in the conservatively managed population.

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Visualization of Cranial Nerves Using High-Definition Fiber Tractography

Visualization of Cranial Nerves Using High-Definition Fiber Tractography

Neurosurgery 79:146–165, 2016

Recent studies have demonstrated diffusion tensor imaging tractography of cranial nerves (CNs). Spatial and angular resolution, however, is limited with this modality. A substantial improvement in image resolution can be achieved with high-angle diffusion magnetic resonance imaging and atlas-based fiber tracking to provide detailed trajectories of CNs.

OBJECTIVE: To use high-definition fiber tractography to identify CNs in healthy subjects and patients with brain tumors.

METHODS: Five neurologically healthy adults and 3 patients with brain tumors were scanned with diffusion spectrum imaging that allowed high-angular-resolution fiber tracking. In addition, a 488-subject diffusion magnetic resonance imaging template constructed from the Human Connectome Project data was used to conduct atlas space fiber tracking of CNs.

RESULTS: The cisternal portions of most CNs were tracked and visualized in each healthy subject and in atlas fiber tracking. The entire optic radiation, medial longitudinal fasciculus, spinal trigeminal nucleus/tract, petroclival portion of the abducens nerve, and intrabrainstem portion of the facial nerve from the root exit zone to the adjacent abducens nucleus were identified. This suggested that the high-angularresolution fiber tracking was able to distinguish the facial nerve from the vestibulocochlear nerve complex. The tractography clearly visualized CNs displaced by brain tumors. These tractography findings were confirmed intraoperatively.

CONCLUSION: Using high-angular-resolution fiber tracking and atlas-based fiber tracking, we were able to identify all CNs in unprecedented detail. This implies its potential in localization of CNs during surgical planning.

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Pulsatile Dynamics of the Optic Nerve Sheath and Intracranial Pressure

ONS and ICP

Neurosurgery 79:100–107, 2016

Raised intracranial pressure (ICP) may lead to increased stiffness of the optic nerve sheath (ONS).

OBJECTIVE: To develop a method for analyzing ONS dynamics from transorbital ultrasound and investigate a potential difference between patients with raised ICP vs normal ICP.

METHODS: We retrospectively analyzed data from 16 patients (#12 years old) for whom ultrasound image sequences of the ONS had been acquired from both eyes just before invasive measurement of ICP. Eight patients had an ICP $20 mm Hg. The transverse motion on each side of the ONS was estimated from ultrasound, and Fourier analysis was used to extract the magnitude of the displacement corresponding to the heart rate. By calculating the normalized absolute difference between the displacements on each side of the ONS, a measure of ONS deformation was obtained. This parameter was referred to as the deformability index. According to our hypothesis, because deformability is inversely related to stiffness, we expected this parameter to be lower for ICP $20 mm Hg compared with ICP ,20 mm Hg. The one-sided Mann-Whitney U test was used for statistical comparison.

RESULTS: The deformability index was significantly lower in the group with ICP $20 mm Hg (median value 0.11 vs 0.24; P = .002).

CONCLUSION: We present a method for assessment of ONS pulsatile dynamics using transorbital ultrasound imaging. A significant difference was noted between the patient groups, indicating that deformability of the ONS may be relevant as a noninvasive marker of raised ICP. The clinical implications are promising and should be investigated in future clinical studies.

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Semi-quantitative assessment of flow dynamics during indocyanine green video-angiography in the treatment of intracranial dural arteriovenous fistulas

Semi-quantitative assessment of flow dynamics during indocyanine green video-angiography in the treatment of intracranial dural arteriovenous fistulas

Acta Neurochir (2016) 158:1387–1391

Indocyanine green video-angiography (IG-VA) is applied for intraoperative localisation and verification of surgical disconnection of intracranial dural arteriovenous fistulas (iDAVFs).

Method We describe the technique of semiquantitative flow analysis using Flow800 software that implements conventional IG-VA. Our method relies on simple comparison of the fluorescence curves of the exposed vessels, allowing precise localisation of the DAVF draining vein and verification of its surgical disconnection.

Conclusions Semi-quantitative flow analysis with Flow800 software during IG-VA is a reproducible technique that may overcome the limitations of conventional IG-VA in the surgical treatment of DAVFs.

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Hydrocephalus in vein of Galen malformation: etiologies and therapeutic management implications

Hydrocephalus in vein of Galen malformation

Acta Neurochir (2016) 158:1279–1284

Up to now, only little is known about hydrocephalus (HC) in vein of Galen malformation (VGM).We want to present the different etiologies and our long-term experience (1992–2015) in the management of HC.

Methods Out of 44 treated children with VGM, we retrospectively reviewed all cases with HC.We analyzed the etiologies, our treatment results and complications.

Results Twenty-one children (48 %) presented either with HC or developed it over time. In 21% of those cases, high venous pressure was presumably the sole cause. Until 2009, seven of them received ventriculoperitoneal (VP) shunting; six of those resulted in severe postoperative complications. The remaining children have been treated successfully by endovascular embolization. Five out of the 44 children (11 %) developed HC after intraventricular hemorrhage. In four cases, those children were treated with positive results by using transient external ventricular drainages. In one case a VP shunt with highest valve pressure was inserted. Another four children (9 %) presented with aqueductal stenosis-related HC caused by either dilated venous outflow or space-occupying coil masses after embolization. The latter case was successfully treated by ventriculocisternostomy, whereas endovascular treatment decreased the venous outflow in size and thus resolved the HC in the other cases. In the remaining cases (7 %), atrophy due to melting brain syndrome led to HC ex vacuo.

Conclusions HC in VGM is a common phenomenon with several etiologies requiring different treatments. In most cases, embolization of the VGM as sole treatment is completely sufficient in order to decrease high venous pressure. However, certain other causes of HC should be treated in an interdisciplinary setting by specialized neurosurgeons.

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Flatness of the infratentorial space associated with hemifacial spasm

Flatness of the infratentorial space associated with hemifacial spasm

Acta Neurochir (2016) 158:1405–1412

Whether a difference in morphology of the infratentorial space is associated with hemifacial spasm is not well understood. The aim of this study was to analyze the three-dimensional conformation of the infratentorial space and evaluate any possible contribution of morphological characteristics to the development of neurovascular compression leading to hemifacial spasm.

Methods We enrolled 25 patients with hemifacial spasm and matched them by age and sex to controls. The extent of the three-dimensional axes and the volume of the infratentorial space were measured using image analysis software for three-dimensional MRI.We evaluated the correlation between a morphological difference in the infratentorial space and changes in vascular configuration in the brain stem.

Results We found no statistical difference in volumetric analyses. The mean aspect ratio on the coronal plane (the ratio of the Z to X extent) of the infratentorial space in patients with hemifacial spasm was significantly lower (p < 0.01) than that in controls, as was the mean aspect ratio on the sagittal plane (the ratio of Z to Yextent, p <0.01). A smaller sagittal aspect ratio was correlated (p < 0.05) with greater lateral deviation of the basilar artery.

Conclusions Our results suggest that flatness of the superior-inferior dimension of the infratentorial space is an anatomical feature that characterizes patients with hemifacial spasm. We hypothesize that this unique structural variation may exaggerate the lateral deviation of the vertebrobasilar arteries due to arteriosclerosis and exacerbate the space competition among vessels and cranial nerves.

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Endoscopic endonasal anatomy of the ophthalmic artery in the optic canal

Endoscopic endonasal anatomy of the ophthalmic artery in the optic canal

Acta Neurochir (2016) 158:1343–1350

The endoscopic endonasal opening of the optic canal has been recently proposed for tumors with medial invasion of this canal, such as tuberculum sellae meningiomas. Injury of the ophthalmic artery represents a dramatic risk during this maneuver. Therefore, the aim of this study was to analyze the endoscopic endonasal anatomy of the precanalicular and canalicular portion of this vessel, discussing its clinical implication.

Methods The course of the ophthalmic artery was analyzed through five endoscopic endonasal dissections, and 40 nonpathological consecutive MRAs were reviewed.

Results The ophthalmic artery arises from the intradural portion of the supraclinoid internal carotid artery, in 93%of cases about 1.9 mm (range: 1–3) posterior to the falciform ligament. At the entrance into the optic canal, the ophthalmic artery is located infero-medially to the optic nerve in 13 % of cases. In 50 % of these cases the artery moves infero-laterally along its course, remaining in a medial position in the others. In cases with an non medial entrance of the ophthalmic artery, it runs infero-lateral to the optic nerve for its entire canalicular portion, with just one exception.

Conclusion The endoscopic endonasal approach gives a direct, extensive and panoramic view of the course of the precanalicular and canalicular portion of the ophthalmic artery. Dedicated high-field neuroimaging studies are of paramount importance in preoperative planning to evaluate the anatomy of the ophthalmic artery, reducing the risk of jeopardizing the vessel, particularly for those uncommon cases with an infero-medial course of the artery.

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Simultaneous bilateral stereotactic procedure for deep brain stimulation implants

Simultaneous bilateral stereotactic procedure for deep brain stimulation implants

J Neurosurg 125:85–89, 2016

Currently, bilateral procedures involve 2 sequential implants in each of the hemispheres. The present report demonstrates the feasibility of simultaneous bilateral procedures during the implantation of deep brain stimulation (DBS) leads.

Methods Fifty-seven patients with movement disorders underwent bilateral DBS implantation in the same study period. The authors compared the time required for the surgical implantation of deep brain electrodes in 2 randomly assigned groups. One group of 28 patients underwent traditional sequential electrode implantation, and the other 29 patients underwent simultaneous bilateral implantation. Clinical outcomes of the patients with Parkinson’s disease (PD) who had undergone DBS implantation of the subthalamic nucleus using either of the 2 techniques were compared.

Results Overall, a reduction of 38.51% in total operating time for the simultaneous bilateral group (136.4 ± 20.93 minutes) as compared with that for the traditional consecutive approach (220.3 ± 27.58 minutes) was observed. Regarding clinical outcomes in the PD patients who underwent subthalamic nucleus DBS implantation, comparing the preoperative off-medication condition with the off-medication/on-stimulation condition 1 year after the surgery in both procedure groups, there was a mean 47.8% ± 9.5% improvement in the Unified Parkinson’s Disease Rating Scale Part III (UPDRS-III) score in the simultaneous group, while the sequential group experienced 47.5% ± 15.8% improvement (p = 0.96). Moreover, a marked reduction in the levodopa-equivalent dose from preoperatively to postoperatively was similar in these 2 groups. The simultaneous bilateral procedure presented major advantages over the traditional sequential approach, with a shorter total operating time.

Conclusions A simultaneous stereotactic approach significantly reduces the operation time in bilateral DBS procedures, resulting in decreased microrecording time, contributing to the optimization of functional stereotactic procedures.

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Long-Term Results of Stereotactic Radiosurgery for Skull Base Meningiomas

Long-Term Results of Stereotactic Radiosurgery for Skull Base Meningiomas

Neurosurgery 79:58–68, 2016

Gamma knife radiosurgery (GKRS) is well established in the management of inaccessible, recurrent, or residual benign skull base meningiomas. Most series report clinical outcome parameters and complications in the short intermediate period after radiosurgery. Reports of long-term tumor control and neurological status are still lacking.

OBJECTIVE: To report the presentation, treatment, and long-term outcome of skull base meningiomas after GKRS.

METHODS: From a prospectively collected institutional review board-approved database, we selected patients with a World Health Organization grade I skull base meningioma treated with a single-session GKRS and a minimum of 60 months follow-up. One hundred thirty-five patients, 54.1% males (n = 73), form the cohort. Median age was 54 years (19-80). Median tumor volume was 4.7 cm3 (0.5-23). Median margin dose was 15 Gy (7.5-36). Median follow-up was 102.5 months (60.1-235.4). Patient and tumor characteristics were assessed to determine the predictors of neurological function and tumor progression.

RESULTS: At last follow-up, tumor volume control was achieved in 88.1% (n = 119). Post- GKRS clinical improvement or stability was reported in 61.5%. The 5-, 10-, and 15-year actuarial progression-free survival rates were 100%, 95.4%, and 68.8%, respectively. Favorable outcome (both tumor control and clinical preservation/improvement) was attained in 60.8% (n = 79). Pre-GKRS performance status (Karnofsky Performance Scale) was shown to influence tumor progression (P = .001) and post-GKRS clinical improvement/preservation (P = .003).

CONCLUSION: GKRS offers a highly durable rate of tumor control for World Health Organization grade I skull base meningiomas, with an acceptably low incidence of neurological deficits. The Karnofsky Performance Scale at the time of radiosurgery serves as a reliable long-term predictor of overall outcome.

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