Author: cba

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A Randomized, Controlled Trial of Fusion Surgery for Lumbar Spinal Stenosis

lumbar stenosis

N Engl J Med 2016;374:1413-23

The efficacy of fusion surgery in addition to decompression surgery in patients who have lumbar spinal stenosis, with or without degenerative spondylolisthesis, has not been substantiated in controlled trials.

METHODS: We randomly assigned 247 patients between 50 and 80 years of age who had lumbar spinal stenosis at one or two adjacent vertebral levels to undergo either decompression surgery plus fusion surgery (fusiongroup) or decompression surgery alone(decompression-alonegroup). Randomization was stratified according to the presence of preoperative degenerative spondylolisthesis (in 135 patients) or its absence. Outcomes were assessed with the use of patient-reported outcome measures, a 6-minute walk test, and a health economic evaluation. The primary outcome was the score on the Oswestry Disability Index (ODI; which ranges from 0 to 100, with higher scores indicating more severe disability) 2 years after surgery. The primary analysis, which was a per-protocol analysis, did not include the 14 patients who did not receive the assigned treatment and the 5 who were lost to follow-up.

RESULTS: There was no significant difference between the groups in the mean score on the ODI at 2 years (27 in the fusion group and 24 in the decompression-alone group, P=0.24) or in the results of the 6-minute walk test (397 m in the fusion group and 405 m in the decompres- sion-alone group, P=0.72). Results were similar between patients with and those without spondylolisthesis. Among the patients who had 5 years of follow-up and were eligible for inclusion in the 5-year analysis, there were no significant differences between the groups in clinical outcomes at 5 years. The mean length of hospitalization was 7.4 days in the fusion group and 4.1 days in the decompression-alone group (P<0.001). Operating time was longer, the amount of bleeding was greater, and surgical costs were higher in the fusion group than in the decompression-alone group. During a mean follow-up of 6.5 years, additional lumbar spine surgery was performed in 22% of the patients in the fusion group and in 21% of those in the decompression-alone group.

CONCLUSIONS: Among patients with lumbar spinal stenosis, with or without degenerative spondylolisthesis, decompression surgery plus fusion surgery did not result in better clinical outcomes at 2 years and 5 years than did decompression surgery alone.

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Stereotactic Radiosurgery for Arteriovenous Malformations: The Effect of Treatment Period on Patient Outcomes

AVM

Neurosurgery 78:499–509, 2016

Stereotactic radiosurgery (SRS) has been performed on patients with cerebral arteriovenous malformations (AVMs) for over 40 years.

OBJECTIVE: To evaluate the impact of treatment period on obliteration, intracranial hemorrhage (ICH), and radiation-induced complications (RICs).

METHODS: Retrospective comparison of 381 AVM patients having SRS during a 20-year period (group 1, January 1990 through March 1997, n = 160; group 2, April 1997 through December 2009, n = 221). The median radiological and clinical follow-up after initial SRS was 77 months and 93 months, respectively.

RESULTS: Obliteration was 59.1% at 4 years and 85.1% at 8 years. Obliteration was more common in patients with hemispheric or cerebellar AVMs (P = .001), smaller prescription isodose volume (PIV) (P < .001), and group 1 patients (P < .001). The ICH rate was 7.7% at 4 years and 10.6% at 8 years. ICH was more common in older patients (P = .02), patients with deep AVM (P = .01), and larger PIV (P < .001). There was no difference in the ICH rate between the treatment groups (P = .18). The rate of permanent RICs was 4.4% at 4 years and 8.6% at 8 years. RICs were more common with larger PIVs (P < .001) and group 1 patients (P = .02). There was no difference in the number of patients having obliteration without new deficits between the 2 treatment periods (68.8% vs 73.3%, P = .33).

CONCLUSION: Advances in SRS procedures over the past 20 years have resulted in a lower risk of RIC, but fewer patients had AVM obliteration. Increasing the prescription dose for patients with medium- and large-volume AVMs by using current conformal dose-planning techniques may improve the obliteration rate while maintaining a low risk of RICs.

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Safety and Efficacy of Gamma Knife Radiosurgery for the Management of Koos Grade 4 Vestibular Schwannomas

Safety and Efficacy of Gamma Knife Radiosurgery for the Management of Koos Grade 4 Vestibular Schwannomas

Neurosurgery 78:521–530, 2016

Gamma Knife radiosurgery (GKRS) is commonly used in treating small vestibular schwannomas; however, its use for larger vestibular schwannomas is still controversial.

OBJECTIVE: To assess the long-term safety and efficacy of treating eligible Koos grade 4 vestibular schwannomas with GKRS.

METHODS: We conducted a single-center, retrospective evaluation of patient undergoing GKRS for Koos grade 4 vestibular schwannomas. We evaluated clinical, imaging, and treatment characteristics and assessed treatment outcome. Inclusion criteria were tumor size of ≥4 cm3 and follow-up of at least 6 months. Patients with neurofibromatosis type 2 were excluded. Primary outcomes measured were tumor control rate, hearing and facial function preservation rate, and complications. All possible factors were analyzed to assess clinical significance.

RESULTS: Sixty-eight patients met inclusion criteria. Median follow-up was 47 months (range, 6-125 months). Baseline hearing was serviceable in 60%. Median tumor volume at radiosurgery was 7.4 cm3 (range, 4-19 cm3). The median marginal dose used was 12 Gy at the 50% isodose line. Actuarial tumor control rates were 95% and 92% at 2 and 10 years, respectively. Actuarial serviceable hearing preservation rates were 89% and 49% at 2 and 5 years, respectively. Facial nerve preservation was 100%. Clinical complications included balance disturbance (11%), facial pain (10%), facial numbness (5%), and tinnitus (10%). Most complications were mild and transient. Hydrocephalus occurred in 3 patients, requiring ventriculoperitoneal shunt insertion. Larger tumor size was significantly associated with persisting symptoms post-treatment.

CONCLUSION: Patients with Koos grade 4 vestibular schwannomas and minimal symptoms can be treated safely and effectively with GKRS.

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A Cost-Effectiveness Comparison Between Open Transforaminal and Minimally Invasive Lateral Lumbar Interbody Fusions

lateral lumbar interbody fusion

Neurosurgery 78:585–595, 2016

Direct cost comparisons between minimally invasive spine surgeries and the open options are rare.

OBJECTIVE: To compare healthcare costs associated with open transforaminal lumbar interbody fusion (TLIF) and minimally invasive lateral lumbar interbody fusion (LLIF) by calculating the incremental cost-effectiveness ratio (ICER) and to calculate the thresholds for minimum clinically important difference and minimum cost-effective difference for patient-reported outcome measures at the 2-year follow-up.

METHODS: Forty-five patients who underwent single-level TLIF and 29 patients who underwent single-level stand-alone LLIF were included in the comparison. All costs from diagnosis through the 2-year follow-up were available from a comprehensive single-center data bank within a unified hospital system. Payment provided for all spine-related medical resource use from the time of diagnosis through 2 years was recorded. A 0% discount rate was applied. Quality-adjusted life-years (QALYs) were calculated from the EuroQol-5D collected in an unbiased manner. Difference in total cost per QALY gained for LLIF minus that for TLIF was assessed as the estimate of the ICER from a US perspective.

RESULTS: Significant improvements were observed at the 2-year follow-up for both TLIF and LLIF with the Short Form-36 physical component summary, Oswestry Disability Index, visual analog scale back pain and leg pain scores, and EuroQol-5D. ICER calculations revealed similar mean cumulative QALYs gained at the 2-year interval (0.67 for TLIF and 0.60 for LLIF; P = .33). Median total costs of care after TLIF and LLIF were $44 068 and $45 574, respectively (P = .96). Minimum cost-effective difference thresholds with an anchor of ,$50 000 per QALY were higher than minimum clinically important difference thresholds for all patient-reported outcome measures. Total mean cost and EuroQol-5D were statistically equivalent between the 2 treatment groups.

CONCLUSION: TLIF and LLIF produced equivalent 2-year patient outcomes at an equivalent cost-effectiveness profile.

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Neurosurgery for schizophrenia

Neurosurgery for schizophrenia

J Neurosurg 124:917–928, 2016

The main objectives of this review were to provide an update on the progress made in understanding specific circuit abnormalities leading to psychotic symptoms in schizophrenia and to propose rational targets for therapeutic deep brain stimulation (DBS).

Refractory schizophrenia remains a major unsolved clinical problem, with 10%–30% of patients not responding to standard treatment options. Progress made over the last decade was analyzed through reviewing structural and functional neuroimaging studies in humans, along with studies of animal models of schizophrenia. The authors reviewed theories implicating dysfunction in dopaminergic and glutamatergic signaling in the pathophysiology of the disorder, paying particular attention to neurosurgically relevant nodes in the circuit. In this context, the authors focused on an important pathological circuit involving the associative striatum, anterior hippocampus, and ventral striatum, and discuss the possibility of targeting these nodes for therapeutic neuromodulation with DBS. Finally, the authors examined ethical considerations in the treatment of these vulnerable patients.

The functional anatomy of neural circuits relevant to schizophrenia remains of great interest to neurosurgeons and psychiatrists and lends itself to the development of specific targets for neuromodulation. Ongoing progress in the understanding of these structures will be critical to the development of potential neurosurgical treatments of schizophrenia.

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Outcome of conservative and surgical treatment of pyogenic spondylodiscitis

pyogenic spondylodiscitis

Eur Spine J (2016) 25:983–999

Spondylodiscitis is a spinal infection affecting primarily the intervertebral disk and the adjacent vertebral bodies. Currently many aspects of the treatment of pyogenic spondylodiscitis are still a matter of debate.

Purpose The aim of this study was to review the currently available literature systematically to determine the outcome of patients with pyogenic spondylodiscitis for conservative and surgical treatment strategies.

Methods A systematic electronic search of MEDLINE, EMBASE, Cochrane Collaboration, and Web of Science regarding the treatment of pyogenic spondylodiscitis was performed. Included articles were assessed on risk of bias according the Cochrane Handbook for Systematic Reviews of Interventions, and the quality of evidence and strength of recommendation was evaluated according the GRADE approach.

Results: 25 studies were included. Five studies had a high or moderate quality of evidence. One RCT suggest that 6 weeks of antibiotic treatment of pyogenic spondylodiscitis results in a similar outcome when compared to longer treatment duration. However, microorganism-specific studies suggest that at least 8 weeks of treatment is required for S. aureus and 8 weeks of Daptomycin for MRSA. The articles that described the outcome of surgical treatment strategies show that a large variety of surgical techniques can successfully treat spondylodiscitis. No additional long-term beneficial effect of surgical treatment could be shown in the studies comparing surgical versus antibiotic only treatment.

Conclusion There is a strong level of recommendation for 6 weeks of antibiotic treatment in pyogenic spondylodiscitis although this has only been shown by one recent RCT. If surgical treatment is indicated, it has been suggested by two prospective studies with strong level of recommendation that an isolated anterior approach could result in a better clinical outcome.

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Assessing size of pituitary adenomas: a comparison of qualitative and quantitative methods on MR

Assessing size of pituitary adenomas- a comparison of qualitative and quantitative methods on MR

Acta Neurochir (2016) 158:677–683

A variety of methods are used for estimating pituitary tumour size in clinical practice and in research. Quantitative methods, such as maximum tumour dimension, and qualitative methods, such as Hardy and Knosp grades, are well established but do not give an accurate assessment of the tumour volume. We therefore sought to compare existing measures of pituitary tumours with more quantitative methods of tumour volume estimation.

Method Magnetic resonance imaging was reviewed for 99 consecutive patients with pituitary adenomas awaiting surgery between 2010 and 2013. Maximal tumour diameter, Hardy and Knosp grades were compared with tumour volume estimates by the ellipsoid equation, [4/3 π (a.b.c) ], (i.e. ellipsoid volume) and slice-by-slice perimetry (i.e. perimeter volume).

Results Ellipsoid and perimeter methods of tumour volume estimation strongly correlated (R2 = 0.99, p < 0.0001). However the correlation was less strong with increasing tumour size, with the ellipsoid method slightly underestimating. The mean differences were −0.11 (95 % CI, −0.35, 0.14), −0.74 (95 % CI, −2.2, 0.74) and −1.4 (95 % CI, −6.4, 3.7) for micro-tumours, macro-tumours and giant tumours respectively. Tumour volume correlated with maximal diameter, fol- lowing a cubic distribution. Correlations of tumour volume with Hardy and Knosp grades was less strong.

Conclusions Perimeter and ellipsoid methods give a good estimation of tumour volume, whereas Knosp and Hardy grades may offer other clinically relevant information, such as cavernous sinus invasion or chiasmal compression. Thus the different methods of estimating tumour size are likely to have different clinical utilities.

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Treatment of Basilar Invagination With Klippel-Feil Syndrome

Treatment of Basilar Invagination With Klippel-Feil Syndrome

Neurosurgery 78:492–498, 2016

Klippel-Feil syndrome (KFS) is characterized by congenital vertebral fusion of the cervical spine and a wide spectrum of associated anomalies. In patients with KFS with basilar invagination (BI), compression of the brainstem and upper cervical cord results in neurological deficits, and decompression and occipitocervical reconstruction are required. The highly varied anatomy of KFS makes a posterior occipitocervical fixation strategy challenging. For these patients, the transoral atlantoaxial reduction plate (TARP) operation is an optimal option to perform a direct anterior fixation to achieve stabilization.

OBJECTIVE: To evaluate the effectiveness of TARP internal fixation for the treatment of BI with KFS. METHODS: Ten consecutive patients with BI and KFS who underwent TARP reduction and fixation from 2010 to 2012 were reviewed. Clinical assessment and image measurements were performed preoperatively and at the most recent follow-up. Nine patients (9/10) were followed for an average of 31.44 months.

RESULTS: Symptoms were alleviated in 9 of 9 patients (100.00%). The odontoid process was ideally corrected with the TARP system. The mean clivus canal angle improved from 124 preoperatively to 152 postoperatively. The average preoperative and postoperative Japanese Orthopedic Association scores were 10.56 (n = 9) and 14.67 (n = 9), respectively, indicating 63.82% improvement. There was bony bridge catenation on the computed tomography scans and no evidence of hardware failure at 6 months.

CONCLUSION: The TARP operation is effective and safe for treating patients with BI with KFS. The midterm clinical results were satisfactory.

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Parkinson’s disease outcomes after intraoperative CT-guided “asleep” deep brain stimulation in the globus pallidus internus

Parkinson’s disease outcomes after intraoperative CT-guided “asleep” deep brain stimulation in the globus pallidus internus

J Neurosurg 124:902–907, 2016

Recent studies show that deep brain stimulation can be performed safely and accurately without microelectrode recording or test stimulation but with the patient under general anesthesia. The procedure couples techniques for direct anatomical targeting on MRI with intraoperative imaging to verify stereotactic accuracy. However, few authors have examined the clinical outcomes of Parkinson’s disease (PD) patients after this procedure. The purpose of this study was to evaluate PD outcomes following “asleep” deep brain stimulation in the globus pallidus internus (GPi).

Methods The authors prospectively examined all consecutive patients with advanced PD who underwent bilateral GPi electrode placement while under general anesthesia. Intraoperative CT was used to assess lead placement accuracy. The primary outcome measure was the change in the off-medication Unified Parkinson’s Disease Rating Scale motor score 6 months after surgery. Secondary outcomes included effects on the 39-Item Parkinson’s Disease Questionnaire (PDQ-39) scores, on-medication motor scores, and levodopa equivalent daily dose. Lead locations, active contact sites, stimulation parameters, and adverse events were documented.

Results Thirty-five patients (24 males, 11 females) had a mean age of 61 years at lead implantation. The mean radial error off plan was 0.8 mm. Mean coordinates for the active contact were 21.4 mm lateral, 4.7 mm anterior, and 0.4 mm superior to the midcommissural point. The mean off-medication motor score improved from 48.4 at baseline to 28.9 (40.3% improvement) at 6 months (p < 0.001). The PDQ-39 scores improved (50.3 vs 42.0; p = 0.03), and the levodopa equivalent daily dose was reduced (1207 vs 1035 mg; p = 0.004). There were no significant adverse events.

Conclusions Globus pallidus internus leads placed with the patient under general anesthesia by using direct anatomical targeting resulted in significantly improved outcomes as measured by the improvement in the off-medication motor score at 6 months after surgery.

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Comparison of Outcome Between Surgical and Conservative Management of Symptomatic Spinal Cord Cavernous Malformations

Comparison of Outcome Between Surgical and Conservative Management of Symptomatic Spinal Cord Cavernous Malformations

Neurosurgery 78:552–561, 2016

Intramedullary cavernous malformations (CMs) are rare lesions with unclear natural history.

OBJECTIVE: To compare the functional outcomes of spinal CMs managed surgically and conservatively.

METHODS: We performed a retrospective study of patients diagnosed with intramedullary CMs seen at our institution from 2006 to 2013. Functional outcomes of patients were assessed by treatment modality with the Modified McCormick Scale and Karnofsky Performance Status.

RESULTS: We identified a total of 85 study-eligible patients; 51 (60.0%) were male. Mean age of patients was 40.5 years. Fifty-eight patients underwent microsurgical removal, and 27 patients underwent conservative management. All patients except 1 harbored a single symptomatic intramedullary CM. Mean follow-up time was 42.8 months. For the surgical group (n = 58), 51 CMs were completely resected. During the follow-up period, 40 patients (69.0%) within the surgical group had improvement in neurological state, 16 patients (27.6%) remained unchanged, and 2 patients (3.4%) experienced deteriorated functional status. In the conservative group, 4 patients (14.8%) had improvement of their symptoms, 19 patients (70.4%) remained in baseline, and 4 patients (14.8%) deteriorated. No significant statistical difference was observed in followup Karnofsky Performance Status assessment (odds ratio = 0.89; 95% confidence interval = 0.73-1.08; P = .15) or Modified McCormick Scale assessment (odds ratio = 0.90; 95% confidence interval = 0.74-1.10; P = .30) after adjustment for preoperative lesion size and location. Annual hemorrhagic risk was 3.9% in conservatively managed patients. In contrast, no patients experienced subsequent hemorrhages after surgical resection.

CONCLUSION: Surgical resection of intramedullary CMs eliminates the risk of subsequent hemorrhagic and may achieve satisfactory outcome when patients are carefully selected. Although conservative management is recommended in patients at high surgical risk, they should be closely monitored because of persistent hemorrhagic risk.

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Combining 5-Aminolevulinic Acid Fluorescence and Intraoperative Magnetic Resonance Imaging in Glioblastoma Surgery

Combining 5-Aminolevulinic Acid Fluorescence and Intraoperative Magnetic Resonance Imaging in Glioblastoma Surgery

Neurosurgery 78:475–483, 2016

Glioblastoma resection guided by 5-aminolevulinic acid (5-ALA) fluorescence and intraoperative magnetic resonance imaging (iMRI) may improve surgical results and prolong survival.

OBJECTIVE: To evaluate 5-ALA fluorescence combined with subsequent low-field iMRI for resection control in glioblastoma surgery.

METHODS: Fourteen patients with suspected glioblastoma suitable for complete resection of contrast-enhancing portions were enrolled. The surgery was carried out using 5-ALA–induced fluorescence and frameless navigation. Areas suspicious for tumor underwent biopsy. After complete resection of fluorescent tissue, low-field iMRI was performed. Areas suspicious for tumor remnant underwent biopsy under navigation guidance and were resected. The histological analysis was blinded.

RESULTS: In 13 of 14 cases, the diagnosis was glioblastoma multiforme. One lymphoma and 1 case without fluorescence were excluded. In 11 of 12 operations, residual contrast enhancement on iMRI was found after complete resection of 5-ALA fluorescent tissue. In 1 case, the iMRI enhancement was in an eloquent area and did not undergo a biopsy. The 28 biopsies of areas suspicious for tumor on iMRI in the remaining 10 cases showed tumor in 39.3%, infiltration zone in 25%, reactive central nervous system tissue in 32.1%, and normal brain in 3.6%. Ninety-three fluorescent and 24 non-fluorescent tissue samples collected before iMRI contained tumor in 95.7% and 87.5%, respectively.

CONCLUSION: 5-ALA fluorescence–guided resection may leave some glioblastoma tissue undetected. MRI might detect areas suspicious for tumor even after complete resection of all fluorescent tissue; however, due to the limited accuracy of iMRI in predicting tumor remnant (64.3%), resection of this tissue has to be considered with caution in eloquent regions.

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Headache in Patients With Pituitary Lesions

Intraoperative high-field MRI for transsphenoidal reoperations of nonfunctioning pituitary adenoma

Neurosurgery 78:316–323, 2016

Headache is a presenting feature in 37% to 70% of patients with pituitary tumor. Other pituitary lesions may also present with headache, and together these lesions account for about 20% of all primary brain lesions. Although pituitary lesions have been associated with headache, the exact nature of the relationship remains undefined. It is not always clear whether the presenting headache is an unrelated primary headache, a lesion-induced aggravation of a preexisting primary headache, or a separate secondary headache related to the lesion.

OBJECTIVE: To characterize headache in patients referred to a multidisciplinary neuroendocrine clinic with suspected pituitary lesions and to assess changes in headache in those who underwent surgery.

METHODS: We used a self-administered survey of headache characteristics completed by patients upon presentation and after any pituitary surgical procedure.

RESULTS: One hundred thirty-three participants completed the preoperative questionnaire (response rate of 99%). The overall prevalence of headache was 63%. Compared to patients without headache, the group with headache was more likely to be female (P = .001), younger (P = .001), and to have had a prior headache diagnosis (P < .001). Seventy-two percent of patients reported headache localized to the anterior region of the head. Fifty-one patients with headache underwent transsphenoidal pituitary surgery. Headache was not associated with increased odds of having surgery (odds ratio, 0.90). At 3 months, 81% of surgically treated patients with headache who completed the postoperative questionnaire (21/26) reported improvement or resolution of headaches. No patient who completed the postoperative questionnaire (44/84) reported new or worsened headache.

CONCLUSION: Frequent, disabling headaches are common in patients with pituitary lesions referred for neuroendocrine consultation, especially in younger females with a preexisting headache disorder. Surgery in this group was associated with headache improvement or resolution in the majority and was not found to cause or worsen headaches. Suggestions for revision of the International Classification of Headache Disorders diagnostic criteria pertaining to pituitary disorders are supported by these findings.

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Combined vascularized tissue flaps for skull base fracture repair

Extensive traumatic anterior skull base fractures with cerebrospinal fluid leak

J Neurosurg 124:647–656, 2016

This article introduces a classification scheme for extensive traumatic anterior skull base fracture to help stratify surgical treatment options. The authors describe their multilayer repair technique for cerebrospinal fluid (CSF) leak resulting from extensive anterior skull base fracture using a combination of laterally pediculated temporalis fascial– pericranial, nasoseptal-pericranial, and anterior pericranial flaps.

Methods: Retrospective chart review identified patients treated surgically between January 2004 and May 2014 for anterior skull base fractures with CSF fistulas. All patients were treated with bifrontal craniotomy and received pedicled tissue flaps. Cases were classified according to the extent of fracture: Class I (frontal bone/sinus involvement only); Class II (extent of involvement to ethmoid cribriform plate); and Class III (extent of involvement to sphenoid bone/sinus). Surgical repair techniques were tailored to the types of fractures. Patients were assessed for CSF leak at follow-up. The Fisher exact test was applied to investigate whether the repair techniques were associated with persistent postoperative CSF leak.

Results: Forty-three patients were identified in this series. Thirty-seven (86%) were male. The patients’ mean age was 33 years (range 11–79 years). The mean overall length of follow-up was 14 months (range 5–45 months). Six fractures were classified as Class I, 8 as Class II, and 29 as Class III. The anterior pericranial flap alone was used in 33 patients (77%). Multiple flaps were used in 10 patients (3 salvage) (28%)—1 with Class II and 9 with Class III fractures. Five (17%) of the 30 patients with Class II or III fractures who received only a single anterior pericranial flap had persistent CSF leak (p < 0.31). No CSF leak was found in patients who received multiple flaps. Although postoperative CSF leak occurred only in high-grade fractures with single anterior flap repair, this finding was not significant.

Conclusions: Extensive anterior skull base fractures often require aggressive treatment to provide the greatest longterm functional and cosmetic benefits. Several vascularized tissue flaps can be used, either alone or in combination. Vascularized flaps are an ideal substrate for cranial base repair. Dual and triple flap techniques that combine the use of various anterior, lateral, and nasoseptal flaps allow for a comprehensive arsenal in multilayered skull base repair and salvage therapy for extensive and severe fractures.

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Comparative analysis of outcomes following craniotomy and expanded endoscopic endonasal transsphenoidal resection of craniopharyngioma and related tumors

Endoscopic endonasal surgery for craniopharyngiomas

J Neurosurg 124:627–638, 2016

Craniopharyngiomas and similar midline suprasellar tumors have traditionally been resected via transcranial approaches. More recently, expanded endoscopic endonasal transsphenoidal approaches have gained interest. Surgeons have advocated for both approaches, and at present there is no consensus whether one approach is superior to the other. The authors therefore compared surgical outcomes between craniotomy and endoscopic endonasal transsphenoidal surgery (EETS) for suprasellar tumors treated at their institution.

Methods: A retrospective review of patients undergoing resection of suprasellar lesions at Cedars-Sinai Medical Center between 2000 and 2013 was performed. Patients harboring suspected craniopharyngioma were selected for extensive review. Other pathologies or predominantly intrasellar masses were excluded. Cases were separated into 2 groups, based on the surgical approach taken. One group underwent EETS and the other cohort underwent craniotomy. Patient demographic data, presenting symptoms, and previous therapies were tabulated. Preoperative and postoperative tumor volume was calculated for each case based on MRI. Student t-test and the chi-square test were used to evaluate differences in patient demographics, tumor characteristics, and outcomes between the 2 cohorts. To assess for selection bias, 3 neurosurgeons who did not perform the surgeries reviewed the preoperative imaging studies and clinical data for each patient in blinded fashion and indicated his/her preferred approach. These data were subject to concordance analysis using Cohen’s kappa test to determine if factors other than surgeon preference influenced the choice of surgical approach.

Results: Complete data were available for 53 surgeries; 19 cases were treated via EETS, and 34 were treated via craniotomy. Patient demographic data, preoperative symptoms, and tumor characteristics were similar between the 2 cohorts, except that fewer operations for recurrent tumor were observed in the craniotomy cohort compared with EETS (17.6% vs 42.1%, p = 0.05). The extent of resection was similar between the 2 groups (85.6% EETS vs 90.7% craniotomy, p = 0.77). An increased rate of cranial nerve injury was noted in the craniotomy group (0% EETS vs 23.5% craniotomy, p = 0.04). Postoperative CSF leak rate was higher in the EETS group (26.3% EETS vs 0% craniotomy, p = 0.004). The progression-free survival curves (log-rank p = 0.99) and recurrence rates (21.1% EETS vs 23.5% craniotomy, p = 1.00) were similar between the 2 groups. Concordance analysis of cases reviewed by 3 neurosurgeons indicated that individual surgeon preference was the only factor that determined surgical approach (kappa coefficient -0.039, p = 0.762)

Conclusions: Surgical outcomes were similar for tumors resected via craniotomy or EETS, except that more CSF leaks occurred in the EETS cohort, whereas more neurological injuries occurred in the craniotomy cohort. Surgical approach appears to mostly reflect surgeon preference rather than specific tumor characteristics. These data support the view that EETS is a viable alternative to craniotomy, providing a similar extent of resection with less neurological injury.

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Trigeminal and sphenopalatine ganglion stimulation for intractable craniofacial pain

Trigeminal and sphenopalatine ganglion stimulation for intractable craniofacial pain

Acta Neurochir (2016) 158:513–520

Facial pain is often debilitating and can be characterized by a sharp, stabbing, burning, aching, and dysesthetic sensation. Specifically, trigeminal neuropathic pain (TNP), anesthesia dolorosa, and persistent idiopathic facial pain (PIFP) are difficult diseases to treat, can be quite debilitating and an effective, enduring treatment remains elusive.

Methods We retrospectively reviewed our early experience with stimulation involving the trigeminal and sphenopalatine ganglion stimulation for TNP, anesthesia dolorosa, and PIFP between 2010–2014 to assess the feasibility of implanting at these ganglionic sites. Seven patients received either trigeminal and/or sphenopalatine ganglion stimulation with or without peripheral nerve stimulation, having failed multiple alternative modalities of treatment. The treatments were tailored on the physical location of pain to ensure regional coverage with the stimulation.

Results Fluoroscopy or frameless stereotaxy was utilized to place the sphenopalatine and/or trigeminal ganglion stimulator. All patients were initially trialed before implantation. Trial leads implanted in the pterygopalatine fossa near the sphenopalatine ganglion were implanted via transpterygoid (lateral-medial, infrazygomatic) approach. Trial leads were implanted in the trigeminal ganglion via percutaneous Hartel approach, all of which resulted in masseter contraction. Patients who developed clinically significant pain improvement underwent implantation. The trigeminal ganglion stimulation permanent implants involved placing a grid electrode over Meckel’s cave via subtemporal craniotomy, which offered a greater ability to stimulate subdivisions of the trigeminal nerve, without muscular (V3) side effects. Two of the seven overall patients did not respond well to the trial and were not implanted. Five patients reported pain relief with up to 24- month follow-up. Several of the sphenopalatine ganglion stimulation patients had pain relief without any paresthesias. There were no electrode migrations or post-surgical complications.

Conclusions Refractory facial pain may respond positively to ganglionic forms of stimulation. It appears safe and durable to implant electrodes in the pterygopalatine fossa via a lateral transpterygoid approach. Also, implantation of an electrode grid overlying Meckel’s cave appears to be a feasible alternative to the Hartel approach. Further investigation is needed to evaluate the usefulness of these approaches for various facial pain conditions.

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Microembolism after endovascular coiling of unruptured cerebral aneurysms: incidence and risk factors

Microembolism after endovascular coiling of unruptured cerebral aneurysms

J Neurosurg 124:777–783, 2016

The incidence and risk factors of microembolic lesions on MR diffusion-weighted imaging (DWI) were analyzed after the endovascular coiling of unruptured intracranial aneurysms (UIAs).

Methods Data obtained from 271 consecutive patients (70 men and 201 women; median age 57 years; range 23–79 years) who presented with UIA for coil embolization between July 2011 and June 2013 were analyzed. Two independent reviewers examined the DWI and apparent diffusion coefficient maps obtained the following day for the presence of restrictive diffusion spots and counted the number of spots. Multivariate analysis was then performed to identify independent risk factors for developing microembolism following the coiling of an aneurysm.

Results Microembolic lesions were noted in 101 of 271 patients (37.3%). The results of the multivariate analysis showed that the following factors significantly influenced the risk for microembolism: age, diabetes, previous history of ischemic stroke, high-signal FLAIR lesions in the white matter, multiple aneurysms, and the insertion of an Enterprise stent (all ORs > 1.0 and all p values < 0.05). Previously known risk factors such as prolonged procedure duration, aneurysm size, and decreased antiplatelet function did not show any significant influence.

Conclusions The incidence of microembolism after endovascular coiling of UIA was not low. Lesions occurred more frequently in patients with vascular status associated with old age, diabetes, and previous stroke. Aneurysm multiplicity and the type of stent used for treatment also influenced lesion occurrence.

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Posterior Reduction of Fixed Atlantoaxial Dislocation and Basilar Invagination by Atlantoaxial Facet Joint Release and Fixation

Posterior Reduction of Fixed Atlantoaxial Dislocation and Basilar Invagination by Atlantoaxial Facet Joint Release and Fixation- A Modified Technique With 174 Cases

Neurosurgery 78:391–400, 2016

Treatment of fixed atlantoaxial dislocation (AAD) with basilar invagination (BI) is challenging.

OBJECTIVE: To introduce a modified technique to reduce fixed AAD and BI through a posterior approach.

METHODS: From 2007 to 2013, 174 patients with fixed AAD and BI underwent surgical reduction by posterior atlantoaxial facet joint release and fixation technique.

RESULTS: There was 1 death in the series, and 3 patients were lost to follow-up. The follow-up period ranged from 12 to 52 months (mean: 35.2 months) for the remaining 170 patients. Neurological improvement was observed in 168 of 170 patients (98.8%), and was stable in 1 (0.06%) and exacerbated in 1 (0.06%), with the Japanese Orthopedic Association scores increasing from 11.4 preoperatively to 15.8 postoperatively (P , .01). Radiologically, complete or .90% reduction was attained in 107 patients (62.9%), 60% to 90% reduction was attained in 51 patients (30%), and ,50% reduction was attained in 12 patients (7.1%), who underwent additional transoral decompression. Complete decompression was demonstrated in all 170 patients. Solid bony fusion was demonstrated in 167 patients at follow-up (98.2%).

CONCLUSION: This series showed the safety and efficacy of the posterior C1-2 facet joint release and reduction technique for the treatment of AAD and BI. Most fixed AAD and BI cases are reducible via this method. In most cases, this method avoids transoral odontoidectomy and cervical traction. Compared with the occiput-C2 screw method, this short-segment C1-2 technique exerts less antireduction shearing force, guarantees longer bone purchase, and provides more immediate stabilization.

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Is Intracranial Pressure Monitoring of Patients With Diffuse Traumatic Brain Injury Valuable?

ICP

Neurosurgery 78:361–369, 2016

Although intracranial pressure (ICP) monitoring of patients with severe traumatic brain injury (TBI) is recommended by the Brain Trauma Foundation, any benefits remain controversial.

OBJECTIVE: To evaluate the effects of ICP monitoring on the mortality of and functional outcomes in patients with severe diffuse TBI.

METHODS: Data were collected on patients with severe diffuse TBI (Glasgow Coma Scale [GCS] score on admission ,9 and Marshall Class II-IV) treated from January 2012 to December 2013 in 24 hospitals (17 level I trauma centers and 7 level II trauma centers) in 9 Chinese provinces. We evaluated the impact of ICP monitoring on 6-month mortality and favorable outcome using propensity score–matched analysis after controlling for independent predictors of these outcomes.

RESULTS: ICP monitors were inserted into 287 patients (59.5%). After propensity score matching, ICP monitoring significantly decreased 6-month mortality. ICP monitoring also had a greater impact on the most severely injured patients on the basis of head computed tomography data (Marshall computed tomography classification IV) and on patients with the lowest level of consciousness (GCS scores 3-5). After propensity score matching, monitoring remained nonassociated with a 6-month favorable outcome for the overall sample. However, monitoring had a significant impact on the 6-month favorable outcomes of patients with the lowest level of consciousness (GCS scores 3-5).

CONCLUSION: ICP monitor placement was associated with a significant decrease in 6-month mortality after adjustment for the baseline risk profile and the monitoring propensity of patients with diffuse severe TBI, especially those with GCS scores of 3 to 5 or of Marshall computed tomography classification IV.

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Orientation of the facet joints in degenerative rotatory lumbar scoliosis

Orientation of the facet joints in degenerative rotatory lumbar scoliosis- an MR study on 52 patients

Acta Neurochir (2016) 158:473–479

Because of a degenerative component, degenerative rotatory scoliosis seems different from congenital and idiopathic subtypes of the disease. This study aims to examine the orientation of facet joints, as a known cause of degeneration, in patients with degenerative rotatory scoliosis.

Methods Lumbar magnetic resonance (MR) images and plain radiographs of 52 symptomatic patients (mean age, 50.17 years) with degenerative rotatory lumbar scoliosis (mean curve, 19.22 degrees) and 50 healthy individuals were reviewed. Facet joint angles in rotated segments and the minimum neural foramen width at all lumbar levels were measured by three observers and the average was recorded.

Results The maximum vertebral rotation was most frequent at L4-L5 (75 %), and the majority was of type I (84.6 %) according to the Nash-Moe classification. At all lumbar spinal levels the mean facet joint angles were significantly higher on the side of rotation (L2-L3, 57.92 degrees; L3-L4, 45.00 degrees; L4-L5, 43.88 degrees) compared to those on the contralateral side (L2-L3, 20.42 degrees; L3-L4, 15.48 degrees; L4-L5, 13.12 degrees) and in controls (L2-L3, 30.21 degrees; L3- L4, 40.81 degrees; L4-L5, 45.20 degrees) (p<0.001 for all comparisons). The mean facet joint angle increased significantly from L4-L5 to L2-L3 in cases and reversely in controls. The mean minimum neural foramen width was 1.29 ± 0.85 mm on the side of rotation, 5.50 ± 1.09 mm on the contralateral side, and 6.78± 1.75 mm in controls (p<0.001).

Conclusions Substantial asymmetries and abnormal orientations in facet joints were documented in patients with degenerative rotatory lumbar scoliosis. Such asymmetries may adversely affect neural foramen width.

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Motor cortex stimulation and neuropathic pain: how does motor cortex stimulation affect pain-signaling pathways?

Motor cortex stimulation and neuropathic pain- how does motor cortex stimulation affect pain-signaling pathways?

J Neurosurg 124:866–876, 2016

Neuropathic pain is often severe. Motor cortex stimulation (MCS) is used for alleviating neuropathic pain, but the mechanism of action is still unclear. This study aimed to understand the mechanism of action of MCS by investigating pain-signaling pathways, with the expectation that MCS would regulate both descending and ascending pathways.

Methods Neuropathic pain was induced in Sprague-Dawley rats. Surface electrodes for MCS were implanted in the rats. Tactile allodynia was measured by behavioral testing to determine the effect of MCS. For the pathway study, immunohistochemistry was performed to investigate changes in c-fos and serotonin expression; micro–positron emission tomography (mPET) scanning was performed to investigate changes of glucose uptake; and extracellular electrophysiological recordings were performed to demonstrate brain activity.

Results MCS was found to modulate c-fos and serotonin expression. In the mPET study, altered brain activity was observed in the striatum, thalamic area, and cerebellum. In the electrophysiological study, neuronal activity was increased by mechanical stimulation and suppressed by MCS. After elimination of artifacts, neuronal activity was demonstrated in the ventral posterolateral nucleus (VPL) during electrical stimulation. This neuronal activity was effectively suppressed by MCS.

Conclusions This study demonstrated that MCS effectively attenuated neuropathic pain. MCS modulated ascending and descending pain pathways. It regulated neuropathic pain by affecting the striatum, periaqueductal gray, cerebellum, and thalamic area, which are thought to regulate the descending pathway. MCS also appeared to suppress activation of the VPL, which is part of the ascending pathway.

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