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Adult Pilocytic Astrocytoma: An Institutional Series and Systematic Literature Review for Extent of Resection and Recurrence

World Neurosurg. (2018) 110:276-283

Pilocytic astrocytoma is a classically benign tumor that most often affects pediatric patients. Rarely, it occurs during adulthood. We present a case series and systematic literature review of adult pilocytic astrocytoma (APA) to examine the clinical presentation, extent of resection, and recurrence rate associated with this tumor in this population.

MATERIALS AND METHODS: Our institutional records were retrospectively reviewed for cases of pilocytic astrocytoma in adults. A PubMed search identified English-language studies of pathology-proven APA. A meta-analysis was performed to determine the relationship between extent of tumor resection and recurrence.

RESULTS: Forty-six patients with APA were diagnosed at our institution (mean age 33.6  13.3; 24 [52%] female). Twenty-four patients (52%) underwent gross total resection, 11 (24%) subtotal resection, 4 (9%) near total resection, 4 (9%) observation after biopsy, and 3 (6%) radiotherapy alone. Tumors recurred or progressed in 6 (13%) patients, of whom 4 were treated by STR and 2 were treated by radiotherapy alone. Thirty-nine (95%) patients were still alive at last follow-up. A systematic literature review identified 415 patients with APA in 38 studies. Including our case series, 7 studies reported extent of resection, followup, and recurrence. Of 254 patients with a weighted mean follow-up of 77.7  49.6 (31e250) months, 129 (51%) were treated with gross total resection, and 125 (49%) underwent subtotal resection. Tumor recurred in 79 (31%) patients, 22 (27%) after gross total resection and 57 (73%) after subtotal resection (P < 0.001).

CONCLUSIONS: Pilocytic astrocytoma rarely presents during adulthood. Overall, prognosis is favorable and survival rates are high. APA recurrence is more likely after STR, and the goal of surgery should always be GTR when feasible.

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DBS for Tourette syndrome: a single-center series

J Neurosurg 128:596–604, 2018

Tourette syndrome (TS) is a complex neuropsychiatric disorder characterized by multiple motor and phonic tics. While pharmacological and behavioral therapy can be effective in most patients, a subset of patients remains refractory to treatment. Increasing clinical evidence from multiple centers suggests that deep brain stimulation (DBS) of the medial thalamus can be effective in many cases of refractory TS.

METHODS The authors retrospectively reviewed outcomes in 13 patients with refractory TS who underwent medial thalamic DBS performed by their team over a 7-year period. Patients were evaluated by a multidisciplinary team, and preoperative objective assessments were performed using the Yale Global Tic Severity Scale (YGTSS) and Yale-Brown Obsessive Compulsive Scale. YGTSS scores were calculated at visits immediately postoperatively and at the most recent follow-up in patients with a minimum of 6 months of postoperative follow-up. Coordinates of the active DBS contacts were calculated and projected onto each patient’s pre- and postoperative images.

RESULTS Patients showed an average decrease of 37% (p = 0.0063) in the total tic severity at their first postoperative visit. At their latest visit, their scores achieved significance, decreasing from preoperative scores by an average of 50% (p = 0.0014). The average position of the active contact was noted to be at the junction of the posterior ventralis oralis internus/ centromedian-parafascicular nuclei. Device-related complications occurred in 2 patients, necessitating additional surgeries. All patients continued to use the system at last follow-up.

CONCLUSIONS The authors’ data are consistent with the small but growing body of literature supporting DBS of the ventralis oralis internus/centromedian-parafascicular thalamus as an effective and relatively safe treatment for severe, refractory TS.

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ABC/2 Method Does not Accurately Predict Cerebral Arteriovenous Malformation Volume

Neurosurgery 82:220–225, 2018

Stereotactic radiosurgery (SRS) is a treatment option for cerebral arteriovenous malformations (AVMs) to prevent intracranial hemorrhage. The decision to proceed with SRS is usually based on calculated nidal volume. Physicians commonly use the ABC/2 formula, based on digital subtraction angiography (DSA), when counseling patients for SRS.

OBJECTIVE: To determine whether AVM volume calculated using the ABC/2 method on DSA is accuratewhen compared to the exact volume calculated from thin-cut axial sections used for SRS planning.

METHODS: Retrospective search of neurovascular database to identify AVMs treated with SRS from 1995 to 2015. Maximum nidal diameters in orthogonal planes on DSA images were recorded to determine volume using ABC/2 formula. Nidal target volume was extracted from operative reports of SRS. Volumes were then compared using descriptive statistics and paired t-tests.

RESULTS: Ninety intracranial AVMs were identified. Median volume was 4.96 cm3 [interquartile range (IQR) 1.79-8.85] with SRS planning methods and 6.07 cm3 (IQR 1.3-13.6) with ABC/2 methodology. Moderate correlation was seen between SRS and ABC/2 (r = 0.662; P<.001). Paired sample t-tests revealed significant differences between SRS volume and ABC/2 (t = –3.2; P = .002). When AVMs were dichotomized based on ABC/2 volume, significant differences remained (t = 3.1, P = .003 for ABC/2 volume < 7 cm3; t = –4.4, P < .001 for ABC/2 volume > 7 cm3).

CONCLUSION: The ABC/2 method overestimates cerebral AVM volume when compared to volumetric analysis from SRS planning software. For AVMs > 7 cm3, the overestimation is even greater. SRS planning techniques were also significantly different than values derived from equations for cones and cylinders.

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Endoscopic Transseptal Approach with Posterior Nasal Spine Removal: A Wide Surgical Corridor to the Craniovertebral Junction and Odontoid

World Neurosurg. (2018) 110:373-385

The transnasal approach to lesions involving the craniovertebral junction represents a technical challenge because of limited inferior exposure. The endoscopic transseptal approach (EtsA) with posterior nasal spine (PNS) removal is described. This technique can create a wide exposure of the craniovertebral junction, thereby increasing the caudal exposure.

METHODS: On patients undergoing anterior craniovertebral junction decompression, we calculated the degree of exposure on the sagittal plan through a paraseptal route, an EtsA without and with PNS removal. The horizontal exposure and working area with the latter approach were also evaluated.

RESULTS: Five patients underwent the transnasal procedure. The age of patients ranged from 34-71 years. All patients harbored basilar impression. The mean postoperative Nurick grade was improved versus the average preoperative grade. The average follow-up duration was 16 months. All patients underwent occipitocervical fixation. The mean vertical distances, from the clinoid recess to the inferior most limit with the paraseptal approach, EtsA without and with PNS removal were 38.52, 44.12, and 51.16 mm, respectively. The difference between our approach and a standard paraseptal route was statistically significant (P [ 0.041; P< 0.05). The mean horizontal distances were 31.68 mm (mononostril entry) and 35.37 mm (binostril entry). The mean working area was 1795.53 mm2.

CONCLUSIONS: Endoscopic endonasal approaches to the craniovertebral junction are increasing, but the downward extension on the anterior cervical spine represents a limit. Therefore, many surgeons prefer transoral or transcervical approaches. The EtsA with PNS removal allows for a more caudal exposure than the standard paraseptal approach, with reduced nasal trauma.

 

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Effectiveness of endoscopic surgery for supratentorial hypertensive intracerebral hemorrhage: a comparison with craniotomy

J Neurosurg 128:553–559, 2018

The goal of this study was to investigate the effectiveness and practicality of endoscopic surgery for treatment of supratentorial hypertensive intracerebral hemorrhage (HICH) compared with traditional craniotomy.

METHODS The authors retrospectively analyzed 151 consecutive patients who were operated on for treatment of supratentorial HICH between January 2009 and June 2014 in the Department of Neurosurgery at Chinese PLA General Hospital. Patients were separated into an endoscopy group (82 cases) and a craniotomy group (69 cases), depending on the surgery they received. The hematoma evacuation rate was calculated using 3D Slicer software to measure the hematoma volume. Comparisons of operative time, intraoperative blood loss, Glasgow Coma Scale score 1 week after surgery, hospitalization time, and modified Rankin Scale score 6 months after surgery were also made between these groups.

RESULTS There was no statistically significant difference in preoperative data between the endoscopy group and the craniotomy group (p > 0.05). The hematoma evacuation rate was 90.5% ± 6.5% in the endoscopy group and 82.3% ± 8.6% in the craniotomy group, which was statistically significant (p < 0.01). The operative time was 1.6 ± 0.7 hours in the endoscopy group and 5.2 ± 1.8 hours in the craniotomy group (p < 0.01). The intraoperative blood loss was 91.4 ± 93.1 ml in the endoscopy group and 605.6 ± 602.3 ml in the craniotomy group (p < 0.01). The 1-week postoperative Glasgow Coma Scale score was 11.5 ± 2.9 in the endoscopy group and 8.3 ± 3.8 in the craniotomy group (p < 0.01). The hospital stay was 11.6 ± 6.9 days in the endoscopy group and 13.2 ± 7.9 days in the craniotomy group (p < 0.05). The mean modified Rankin Scale score 6 months after surgery was 3.2 ± 1.5 in the endoscopy group and 4.1 ± 1.9 in the craniotomy group (p < 0.01). Patients had better recovery in the endoscopy group than in the craniotomy group. Data are expressed as the mean ± SD.

CONCLUSIONS Compared with traditional craniotomy, endoscopic surgery was more effective, less invasive, and may have improved the prognoses of patients with supratentorial HICH. Endoscopic surgery is a promising method for treatment of supratentorial HICH. With the development of endoscope technology, endoscopic evacuation will become more widely used in the clinic. Prospective randomized controlled trials are needed.

 

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Intended Near-Total Removal of Koos Grade IV Vestibular Schwannomas

Neurosurgery 82:202–210, 2018

The goals of treating Koos grade IV vestibular schwannomas are to relieve brainstem compression, preserve or restore neurological function, and achieve long-term tumor control while minimizing tumor- and treatment-related morbidity.

OBJECTIVE: To propose a treatment paradigm involving the intentional near-total removal of Koos grade IV vestibular schwannomas, in which a small amount of residual tumor is not dissected off the cisternal portion of the facial nerve. Patients are then followed by a wait-and-scan approach. Any subsequent volumetric progression of the residual tumor is treated with radiosurgery.

METHODS: This is a case series of 44 consecutive unselected patients who underwent intended near-total resection of a Koos grade IV vestibular schwannoma through a retrosigmoid approach from January 2009 to December 2015. Pre- and postoperative volumetric analyses were performed on routine magnetic resonance imaging sequences (constructive interference in steady state and gadolinium-enhanced T1- weighted sequence).

RESULTS: The mean preoperative tumor volume was 10.9 cm3. The mean extent of resectionwas 89%. At the last clinical follow-up, facial nerve function was good [House and Brackmann (HB) I-II] in 89%, fair (HB III) in 9%, and poor (HB IV-VI) in 2%of the patients.At the last radiological follow-up, the residual tumor had become smaller or remained the same size in 84% of patients. Volumetric progression was negatively correlated with the original extent of resection and positively correlated with postoperative residual tumor volume (P = .01, P < .001, respectively).

CONCLUSION: Intended near-total removal results in excellent preservation of facial nerve function and has a low recurrence rate. Any progressive residual tumor may be treated by radiosurgery.

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Endoscopic microvascular decompression for hemifacial spasm associated with the vertebral artery

Acta Neurochir (2018) 160:157–159

Microvascular decompression (MVD) of hemifacial spasm (HFS) associated with the vertebral artery (VA) shows higher rates of incomplete cure and complications compared to non-VA-related HFS.

Method Purely endoscopic MVD for VA-associated HFS via a retrosigmoid keyhole was performed. Neurovascular conflicts by a directly offending artery and VA around the root exit zone of the facial nerve were clearly demonstrated under 30° endoscopic view without significant cerebellar retraction. The VA and directly offending artery were safely transposed with preservation of perforators under excellent view.

Conclusion Endoscopic MVD offers reliable decompression for VA-associated HFS with minimal invasiveness.

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Quantitative study of the correlation between cerebellar retraction factors and hearing loss following microvascular decompression for hemifacial spasm

Acta Neurochir (2018) 160:145–150

This prospective study quantitatively measured the cerebellar retraction factors, including retraction distance, depth and duration, and evaluated their potential relationship to the development of hearing loss after microvascular decompression (MVD) for hemifacial spasm (HFS).

Methods One hundred ten patients with primary HFS who underwent MVD in our department were included into this study. The cerebellar retraction factors were quantitatively measured on preoperative MR and timed during MVD. Associations of cerebellar retraction and other factors to postoperative hearing loss were analyzed.

Results Eleven (10%) patients developed hearing loss after MVD. Compared with the group without hearing loss, the cerebellar retraction distance, depth and duration of the group with hearing loss were significantly greater (p < 0.05). Multivariate regression analysis showed that greater cerebellar retraction depth and longer retraction duration were significantly associated with a higher incidence of postoperative hearing impairment (p < 0.05).

Conclusion This study strongly suggested a correlation between the cerebellar retraction factors, especially retraction depth and duration, and possibility of hearing loss following MVD for HFS.

 

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Outcome after Hunt and Hess Grade V subarachnoid hemorrhage: a comparison of pre-coiling era (1980–1995) versus post-ISAT era (2005–2014)

J Neurosurg 128:100–110, 2018

Outcome analysis of comatose patients (Hunt and Hess Grade V) after subarachnoid hemorrhage (SAH) is still lacking. The aims of this study were to analyze the outcome of Hunt and Hess Grade V SAH and to compare outcomes in the current period with those of the pre–International Subarachnoid Aneurysm Trial (ISAT) era as well as with published data from trials of decompressive craniectomy (DC) for middle cerebral artery (MCA) infarction.

METHODS The authors analyzed cases of Hunt and Hess Grade V SAH from 1980–1995 (referred to in this study as the earlier period) and 2005–2014 (current period) and compared the results for the 2 periods. The outcomes of 257 cases were analyzed and stratified on the basis of modified Rankin Scale (mRS) scores obtained 6 months after SAH. Outcomes were dichotomized as favorable (mRS score of 0–2) or unfavorable (mRS score of 3–6). Data and number needed to treat (NNT) were also compared with the results of decompressive craniectomy (DC) trials for middle cerebral artery (MCA) infarctions.

RESULTS Early aneurysm treatment within 72 hours occurred significantly more often in the current period (in 67% of cases vs 22% in earlier period). In the earlier period, patients had a significantly higher 30-day mortality rate (83% vs 39% in the current period) and 6-month mortality rate (94% vs 49%), and no patient (0%) had a favorable outcome, compared with 23% overall in the current period (p < 0.01, OR 32), or 29.5% of patients whose aneurysms were treated (p < 0.01, OR 219). Cerebral infarctions occurred in up to 65% of the treated patients in the current period. Comparison with data from DC MCA trials showed that the NNTs were significantly lower in the current period with 2 for survival and 3 for mRS score of 0–3 (vs 3 and 7, respectively, for the DC MCA trials).

CONCLUSIONS Early and aggressive treatment resulted in a significant improvement in survival rate (NNT = 2) and favorable outcome (NNT = 3 for mRS score of 0–3) for comatose patients with Hunt and Hess Grade V SAH compared with the earlier period. Independent predictors for favorable outcome were younger age and bilateral intact corneal reflexes. Despite a high rate of cerebral infarction (65%) in the current period, 29.5% of the patients who received treatment for their aneurysms during the current era (2005–2014) had a favorable outcome. However, careful individual decision making is essential in these cases.

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Reduced Field-of-View Diffusion Tensor Imaging of the Spinal Cord Shows Motor Dysfunction of the Lower Extremities in Patients With Cervical Compression Myelopathy

Spine 2018;43:89–96

Study Design. A cross-sectional study.

Objective. The aim of this study was to quantify spinal cord dysfunction at the tract level in patients with cervical compressive myelopathy (CCM) using reduced field-of-view (rFOV) diffusion tensor imaging (DTI).

Summary of Background Data. Although magnetic resonance imaging (MRI) is the standard used for radiological evaluation of CCM, information acquired by MRI does not necessarily reflect the severity of spinal cord disorder. There is a growing interest in developing imaging methods to quantify spinal cord dysfunction. To acquire high-resolution DTI, a new scheme using rFOV has been proposed.

Methods. We enrolled 10 healthy volunteers and 20 patients with CCM in this study. The participants were studied using a 3.0-T MRI system. For DTI acquisitions, diffusion-weighted spinecho rFOV single-shot echo-planar imaging was used. Regions of interest (ROI) for the lateral column (LC) and posterior column (PC) tracts were determined on the basis of a map of fractional anisotropy (FA) of the spinal cord and FA values were measured. The FA of patients with CCM was compared with that of healthy controls and correlated with Japanese Orthopaedic Association (JOA) score.

Results. In LC and PC tracts, FA values in patients with CCM were significantly lower than in healthy volunteers. Total JOA scores correlated moderately with FA in LC and PC tracts. JOA subscores for motor dysfunction of the lower extremities correlated strongly with FA in LC and PC tracts.

Conclusion. It is feasible to evaluate the cervical spinal cord at the tract level using rFOV DTI. Although FA values at the maximum compression level were not well correlated with total JOA scores, they were strongly correlated with JOA subscores for motor dysfunction of the lower extremities. Our findings suggest that FA reflects white matter dysfunction below the maximum compression level and FA can be used as an imaging biomarker of spinal cord dysfunction.

Key words: . Level of Evidence: 4

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Brainstem arteriovenous malformations: lesion characteristics and treatment outcomes

J Neurosurg 128:126–136, 2018

Brainstem arteriovenous malformations (AVMs) are rare lesions that are difficult to diagnose and treat. They are often more aggressive in their behavior when compared with their supratentorial counterparts. The consequence of a brainstem hemorrhage is often devastating, and many patients are in poor neurological status at presentation. The authors examine the factors associated with angiographically confirmed cure and those affecting management outcomes for these complex lesions.

METHODS This was a retrospective analysis of data gathered from the prospectively maintained Stanford AVM database. Lesions were grouped based on their location in the brainstem (medulla, pons, or midbrain) and the quadrant they occupied. Angiographic cure was dichotomized as completely obliterated or not, and functional outcome was dichotomized as either independent or not independent at last follow-up.

RESULTS Over a 23-year period, 39 lesions were treated. Of these, 3 were located in the medulla, 14 in the pons, and 22 in the midbrain. At presentation, 92% of the patients had hemorrhage, and only 43.6% were functionally independent. Surgery resulted in the best radiographic cure rates, with a morbidity rate of 12.5%. In all, 53% of patients either improved or remained stable after surgery. Absence of residual nidus and female sex correlated with better outcomes.

CONCLUSIONS Brainstem AVMs usually present with hemorrhage. Surgery offers the best chance of cure, either in isolation or in combination with other modalities as appropriate.

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Long-term follow-up of multimodality treatment for multiple sclerosis-related trigeminal neuralgia

Acta Neurochir (2018) 160:135–144

The treatment for multiple sclerosis-related trigeminal neuralgia (MS-TN) is less efficacious and associated with higher recurrence rates than classical TN. No consensus has been reached in the literature on the choice procedure for MS-TN patients. The aim of this study was to assess the incidence and surgical outcomes of medically refractory MS-TN.

Methods Patient records were retrospectively reviewed for all Manitobans undergoing first procedure for medically refractory MS-TN between 2000 and 2014. Subsequent procedures were then recorded and analyzed in this subgroup of patients. The primary outcome measure was time to treatment failure.

Results The incidence of medically refractory MS-TN was 1.2/million/year. Twenty-one patients with 26 surgically treated sides underwent first rhizotomy including 13 GammaKnife and 13 percutaneous rhizotomies comprised of ten glycerol injections and three balloon compressions. Subsequent procedures were required on 23 sides (88%), including 24 GammaKnife, 19 glycerol injections, 25 balloon compressions, two microvascular decompressions, and four open partial surgical rhizotomies with a total of 99 surgeries on 26 sides (range, 1–12 each).

Conclusions The majority of MS-TN patients become medically refractory and require multiple repeat surgical procedures. MS-TN procedures were associated with high rates of pain recurrence and our data suggests reoperation within 1 year is often necessary. Optimal management strategy in this patient population remains to be determined. Patients need to be counseled on managing expectations as treatments commonly afford only temporary relief.

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Clinical and Radiological Mid-Term Outcomes of Lumbar Single-Level Total Disc Replacement

Spine 2018;43:105–113

Study Design. Prospective single-center case cohort study. Objective. Evaluation of clinical and radiographic outcomes of a consecutive 122-patient cohort with discogenic back pain, at 2- to 10-year follow-up periods, treated by a single surgeon, with CHARITE Artificial Disc (DePuy Spine, Raynham, MA).

Summary of Background Data. Minimum 2-year clinical and radiographic level 1 data for the first lumbar artificial disc, the CHARITE Artificial Disc (DePuy Spine), have recently been published, demonstrating sustained clinical benefit of the device for the treatment of degenerative disc disease.

Methods. Patients were assessed preoperatively using clinical outcome measures, including visual analog scale (VAS) score back and leg, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36), and Roland-Morris Questionnaires (RMDQ), and further assessed postoperatively, 3-, 6-, 12-months, and yearly thereafter.

Results. Average follow-up was 44.9±3.3 months (n=122). The median age at surgery was 43.0±9.0 years. Preoperative diagnosis included degenerative disc disease in 118 (96.7%) and internal disc disruption in 4 (3.3%). Surgery was performed at L5–S1 in 96 (77.9%) patients and at L4–L5 in 27 (22.1%). Statistically significant clinical improvements from baseline were observed on VAS (back and leg), ODI, SF-36 PCS, SF-36 MCS, and RMDQ 3 months onward. Back VAS scores decreased from 78.221.3 preoperatively to 21.927.8 by final follow-up. ODI scores decreased from 51.117.3 to 16.217.9 at last follow-up. The RMDQ scores also decreased from 16.7±4.7 to 4.2±5.8. SF-36 PCS and MCS increased from 25.7±11.0 to 46.4±10.3 for PCS and from 35.5±17.4 to 51.6±10.8 for MCS. Patient satisfaction surveys indicated that 90.56% patients rated their satisfaction with the surgery as ‘‘excellent’’ or ‘‘good’’ at 2 years. Range of motion averaged 8.6±3.5 (median=8.08) at the last follow-up time point.

Conclusion. Outcomes verify the clinical efficacy of total disc replacement for treatment of discogenic back pain with or without radiculopathy. The outcomes instruments demonstrated statistically significant improvements 3 months onward.

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Intraoperative monitoring of sensory part of the trigeminal nerve using blink reflex during microvascular decompression for trigeminal neuralgia

Acta Neurochirurgica (2018) 160:165–169

Intraoperative monitoring during cerebellopontine angle surgery is widely accepted. While techniques which monitor cranial motor nerves are commonly used, monitoring the sensory afferents has been challenging. Considering the reflex arc, blink reflex (BR) might be useful in monitoring the sensory part of the trigeminal nerve, the brainstem connections and the facial nerve.

We describe the case of a patient who developed hemifacial hypoesthesia after microvascular decompression surgery for trigeminal neuralgia. Intraoperative BR showed a severe loss of R1 amplitude.

BR might be a useful intraoperative technique to monitor the sensory part of the trigeminal nerve.

Keywords

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Anterior Communicating Artery Aneurysm Morphology and the Risk of Rupture

World Neurosurg. (2018) 109:119-126.

Recently, with improvements in computed tomography angiography and digital subtraction angiography, the assessment of certain morphologic traits of anterior communicating artery aneurysms (ACoAA) has drawn great attention. The determination of specific factors associated with rupture would provide much-needed guidance for the treatment of unruptured intracranial aneurysms, such as surgical clipping or endovascular coiling. Morphologic factors include, but are not limited to, aneurysm size, number, shape, dome direction, neck/dome ratio, and relationship of the aneurysm to the surrounding vessels. However, the results of previous investigations concerning morphologic parameters have yielded inconsistent results.

METHODS: This review presents and analyzes the literature on the morphology of ACoAAs and risk of rupture.

RESULTS: This literature review reveals that the strongest predictors of ACoAA rupture are size ratio, direction of the dome, and fenestration. These were the only factors that were either unanimously or near unanimously found to be predictive of rupture across multiple studies.

CONCLUSIONS: The size ratio, direction of the dome, and fenestration should be examined most meticulously when deciding when to treat an ACoAA.

 

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Prospective comparison of long-term pain relief rates after first-time microvascular decompression and stereotactic radiosurgery for trigeminal neuralgia

J Neurosurg 128:68–77, 2018

Common surgical treatments for trigeminal neuralgia (TN) include microvascular decompression (MVD), stereotactic radiosurgery (SRS), and radiofrequency ablation (RFA). Although the efficacy of each procedure has been described, few studies have directly compared these treatment modalities on pain control for TN. Using a large prospective longitudinal database, the authors aimed to 1) directly compare long-term pain control rates for first-time surgical treatments for idiopathic TN, and 2) identify predictors of pain control.

METHODS The authors reviewed a prospectively collected database for all patients who underwent treatment for TN between 1997 and 2014 at the University of California, San Francisco. Standardized collection of data on preoperative clinical characteristics, surgical procedure, and postoperative outcomes was performed. Data analyses were limited to those patients who received a first-time procedure for treatment of idiopathic TN with > 1 year of follow-up.

RESULTS Of 764 surgical procedures performed at the University of California, San Francisco, for TN (364 SRS, 316 MVD, and 84 RFA), 340 patients underwent first-time treatment for idiopathic TN (164 MVD, 168 SRS, and 8 RFA) and had > 1 year of follow-up. The analysis was restricted to patients who underwent MVD or SRS. Patients who received MVD were younger than those who underwent SRS (median age 63 vs 72 years, respectively; p < 0.001). The mean follow-up was 59 ± 35 months for MVD and 59 ± 45 months for SRS. Approximately 38% of patients who underwent MVD or SRS had > 5 years of follow-up (60 of 164 and 64 of 168 patients, respectively). Immediate or short-term (< 3 months) postoperative pain-free rates (Barrow Neurological Institute Pain Intensity score of I) were 96% for MVD and 75% for SRS. Percentages of patients with Barrow Neurological Institute Pain Intensity score of I at 1, 5, and 10 years after MVD were 83%, 61%, and 44%, and the corresponding percentages after SRS were 71%, 47%, and 27%, respectively. The median time to pain recurrence was 94 months (25th–75th quartiles: 57–131 months) for MVD and 53 months (25th–75th quartiles: 37–69 months) for SRS (p = 0.006). A subset of patients who had MVD also underwent partial sensory rhizotomy, usually in the setting of insignificant vascular compression. Compared with MVD alone, those who underwent MVD plus partial sensory rhizotomy had shorter pain-free intervals (median 45 months vs no median reached; p = 0.022). Multivariable regression demonstrated that shorter preoperative symptom duration (HR 1.005, 95% CI 1.001–1.008; p = 0.006) was associated with favorable outcome for MVD and that post-SRS sensory changes (HR 0.392, 95% CI 0.213–0.723; p = 0.003) were associated with favorable outcome for SRS.

CONCLUSIONS In this longitudinal study, patients who received MVD had longer pain-free intervals compared with those who underwent SRS. For patients who received SRS, postoperative sensory change was predictive of favorable outcome. However, surgical decision making depends upon many factors. This information can help physicians counsel patients with idiopathic TN on treatment selection.

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A New Volumetric Radiologic Method to Assess Indirect Decompression After Extreme Lateral Interbody Fusion Using High-Resolution Intraoperative Computed Tomography

World Neurosurg. (2018)109:59-67

Two-dimensional radiographic methods have been proposed to evaluate the radiographic outcome after indirect decompression through extreme lateral interbody fusion (XLIF). However, the assessment of neural decompression in a single plane may underestimate the effect of indirect decompression on central canal and foraminal volumes. The present study aimed to assess the reliability and consistency of a novel 3-dimensional radiographic method that assesses neural decompression by volumetric analysis using a new generation of intraoperative fan-beam computed tomography scanner in patients undergoing XLIF.

METHODS: Prospectively collected data from 7 patients (9 levels) undergoing XLIF was retrospectively analyzed. Three independent, blind raters using imaging analysis software performed volumetric measurements pre- and postoperatively to determine central canal and foraminal volumes. Intrarater and Interrater reliability tests were performed to assess the reliability of this novel volumetric method.

RESULTS: The interrater reliability between the three raters ranged from 0.800 to 0.952, P < 0.0001. The test-retest analysis on a randomly selected subset of three patients showed good to excellent internal reliability (range of 0.78e1.00) for all 3 raters. There was a significant increase in mean ±20% for right foramen, left foramen, and central canal volumes postoperatively (P = 0.0472; P = 0.0066; P = 0.0003, respectively).

CONCLUSIONS: Here we demonstrate a new volumetric analysis technique that is feasible, reliable, and reproducible amongst independent raters for central canal and foraminal volumes in the lumbar spine using an intraoperative computed tomography scanner

 

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Anterior interhemispheric transsplenial approach to pineal region tumors

J Neurosurg 128:182–192, 2018

Pineal region tumors are challenging to access because they are centrally located within the calvaria and surrounded by critical neurovascular structures.

The goal of this work is to describe a new surgical trajectory, the anterior interhemispheric transsplenial approach, to the pineal region and falcotentorial junction area. To demonstrate this approach, the authors examined 7 adult formalin-fixed silicone-injected cadaveric heads and 2 fresh human brain specimens.

One representative case of falcotentorial meningioma treated through an anterior interhemispheric transsplenial approach is also described.

Among the interhemispheric approaches to the pineal region, the anterior interhemispheric transsplenial approach has several advantages. 1) There are few or no bridging veins at the level of the pericoronal suture. 2) The parietal and occipital lobes are not retracted, which reduces the chances of approach-related morbidity, especially in the dominant hemisphere. 3) The risk of damage to the deep venous structures is low because the tumor surface reached first is relatively vein free. 4) The internal cerebral veins can be manipulated and dissected away laterally through the anterior interhemispheric route but not via the posterior interhemispheric route. 5) Early control of medial posterior choroidal arteries is obtained.

The anterior interhemispheric transsplenial approach provides a safe and effective surgical corridor for patients with supratentorial pineal region tumors that 1) extend superiorly, involve the splenium of the corpus callosum, and push the deep venous system in a posterosuperior or an anteroinferior direction; 2) are tentorial and displace the deep venous system inferiorly; or 3) originate from the splenium of the corpus callosum.

 

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Endoscopic endonasal versus transcranial approach to tuberculum sellae and planum sphenoidale meningiomas

J Neurosurg 128:40–48, 2018

Planum sphenoidale (PS) and tuberculum sellae (TS) meningiomas cause visual symptoms due to compression of the optic chiasm. The treatment of choice is surgical removal with the goal of improving vision and achieving complete tumor removal. Two options exist to remove these tumors: the transcranial approach (TCA) and the endonasal endoscopic approach (EEA). Significant controversy exists regarding which approach provides the best results and whether there is a subset of patients for whom an EEA may be more suitable. Comparisons using a similar cohort of patients, namely, those suitable for gross-total resection with EEA, are lacking from the literature.

METHODS The authors reviewed all cases of PS and TS meningiomas that were surgically removed at Weill Cornell Medical College between 2000 and 2015 (TCA) and 2008 and 2015 (EEA). All cases were shown to a panel of 3 neurosurgeons to find only those tumors that could be removed equally well either through an EEA or TCA to standardize both groups. Volumetric measurements of preoperative and postoperative tumor size, FLAIR images, and apparent diffusion coefficient maps were assessed by 2 independent reviewers and compared to assess extent of resection and trauma to the surrounding brain. Visual outcome and complications were also compared.

RESULTS Thirty-two patients were identified who underwent either EEA (n = 17) or TCA (n = 15). The preoperative tumor size was comparable (mean 5.58 ± 3.42 vs 5.04 ± 3.38 cm3 [± SD], p = 0.661). The average extent of resection achieved was not significantly different between the 2 groups (98.80% ± 3.32% vs 95.13% ± 11.69%, p = 0.206). Postoperatively, the TCA group demonstrated a significant increase in the FLAIR/edema signal compared with EEA patients (4.15 ± 7.10 vs -0.69 ± 2.73 cm3, p = 0.014). In addition, the postoperative diffusion-weighted imaging signal of cytotoxic ischemic damage was significantly higher in the TCA group than in the EEA group (1.88 ± 1.96 vs 0.40 ± 0.55 cm3, p = 0.008). Overall, significantly more EEA patients experienced improved or stable visual outcomes compared with TCA patients (93% vs 56%, p = 0.049). Visual deterioration was greater after TCA than EEA (44% vs 0%, p = 0.012). While more patients experienced postoperative seizures after TCA than after EEA (27% vs 0%, p = 0.038), there was a trend toward more CSF leakage and anosmia after EEA than after TCA (11.8% vs 0%, p = 0.486 and 11.8% vs 0%, p = 0.118, respectively).

CONCLUSIONS In this small single-institution study of similarly sized and located PS and TS meningiomas, EEA provided equivalent rates of resection with better visual results, less trauma to the brain, and fewer seizures. These preliminary results merit further investigation in a larger multiinstitutional study and may support EEA resection by experienced surgeons in a subset of carefully selected PS and TS meningiomas.

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Clinical Presentation, Diagnosis, and Surgical Treatment of Spontaneous Cervical Intradural Disc Herniations

World Neurosurg. (2018) 109:275-284

Spontaneous cervical intradural disc herniation (IDH) is a rare occurrence with limited and disparate information available regarding its presentation, diagnosis, and treatment. However, its accurate detection is vital for planning surgical treatment. In this review of the literature, we collected data from all cervical IDHs described to date. Particular attention was paid to diagnostic findings, surgical approach, and causation for cervical IDH, especially at the cervicothoracic junction.

METHODS: A review for cases of cervical IDH was performed via the following search criteria: (“neck”[MeSH Terms] OR “neck”[All Fields] OR “cervical”[All Fields]) AND intradural[All Fields] AND disc[All Fields]. Thirtyseven cases of cervical disc herniation were identified. Demographic variables identified included age, sex, cervical level of herniation, history of associated cervical trauma, presence of Brown-Séquard syndrome, Horner syndrome, and other neurologic findings, radiographic findings, direction of surgical approach, and postoperative outcomes.

RESULTS: A total of 37 cases of cervical IDH were identified. Most of the cases occurred at the lower levels of the cervical spine, with 35.1% at the C5e C6 level, followed by 24.3% at C6eC7, and lower still at other levels. Of the patients reviewed, 44.4% had a previous history of trauma before manifestation of symptom, with the majority being spontaneous IDH with no previous history of trauma or spine surgery. Brown-Séquard syndrome was present in 43.2% of the patients, whereas 10.8% of patients experienced Horner syndrome. The most common presentations of IDH included quadriplegia, finger/gait ataxia, radiculopathy, and nuchal pain. The degree of neurologic recovery was not associated with patient age. Most of the cervical IDHs in the literature were treated surgically via an anterior approach, but a larger portion of patients who underwent a posterior approach had improved recovery.

CONCLUSIONS: Cervical IDH is a rare event, with this review of the literature outlining the clinical and radiographic parameters of its presentation as well as comparing common surgical strategies for treatment. We outline theories underlying the development of cervical IDH and argue for a posterior surgical approach in which the disc herniation is sequestrated with migration

 

 

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