External Lumbar Drainage following Traumatic Intracranial Hypertension

Neurosurgery 89:395–405, 2021

Traumatic brain injury (TBI) often results in elevations in intracranial pressure (ICP) that are refractory to standard therapies. Several studies have investigated the utility of external lumbar drainage (ELD) in this setting.

OBJECTIVE: To evaluate the safety and efficacy of ELD or lumbar puncture with regard to immediate effect on ICP, durability of the effect on ICP, complications, and neurological outcomes in adults with refractory traumatic intracranial hypertension.

METHODS: A systematic review and meta-analysis were conducted beginning with a comprehensive search of PubMed/EMBASE. Two investigators reviewed studies for eligibility and extracted data. The strength of evidence was evaluated using GRADE methodology. Random-effects meta-analyses were performed to calculate pooled estimates.

RESULTS: Nine articles detailing 6 studies (N = 110) were included. There was moderate evidence that ELD has a significant immediate effect on ICP; the pooled effect size was –19.5 mmHg (95% CI –21.0 to –17.9 mmHg). There was low evidence to indicate a durable effect of ELD on ICP up to at least 24 h following ELD. There was low evidence to indicate that ELD was safe and associated with a low rate of clinical cerebral herniation or meningitis. There was very low evidence pertaining to neurological outcomes.

CONCLUSION: Given preliminary data indicating potential safety and feasibility in highly selected cases, the use of ELD in adults with severe TBI and refractory intracranial hypertension in the presence of open basal cisterns and absence of large focal hematoma merits further high-quality investigation; the ideal conditions for potential application remain to be determined.

Complications of Cranioplasty in Relation to Material: Systematic Review, Network Meta-Analysis and Meta-Regression

Neurosurgery 89:383–394, 2021

Cranioplasty is a ubiquitous neurosurgical procedure consisting of reconstruction of a pre-existing calvarial defect. Many materials are available, including polymethylmethacrylate in hand-moulded (hPMMA) and prefabricated (pPMMA) form, hydroxyapatite (HA), polyetheretherketone (PEEK) and titanium (Ti). OBJECTIVE: To perform a networkmeta-analysis (NMA) to assess the relationship between materials and complications of cranioplasty.

METHODS: PubMed/MEDLINE, Google Scholar, EMBASE, Scopus, and The Cochrane Library were searched from January 1, 1990 to February 14, 2021. Studies detailing rates of any of infections, implant exposure, or revision surgery were included. A frequentist NMA was performed for each complication. Risk ratios (RRs) with 95% CIs were calculated for each material pair.

RESULTS: A total of 3620 abstractswere screened and 31 full paperswere included. Surgical revision was reported in 18 studies and occurred in 316/2032 cases (14%; 95% CI 11-17). PEEK had the lowest risk of re-operation with a rate of 8/157 (5%; 95% CI 0-11) in 5 studies, superior to autografts (RR 0.20; 95% CI 0.07-0.57), hPMMA (RR 0.20; 95% CI 0.07-0.60), Ti (RR 0.39; 95% CI 0.17-0.92), and pPMMA (RR 0.14; 95% CI 0.04-0.51). Revision rate was 131/684 (19%; 95% CI 13-25; 10 studies) in autografts, 61/317 (18%; 95%CI 9-28; 7 studies) in hPMMA, 84/599 (13%; 95% CI 7-19; 11 studies) in Ti, 7/59 (9%; 95% CI 1-23; 3 studies) in pPMMA, and 25/216 (12%; 95%CI 4-24; 4 studies) in HA. Infection occurred in 463/4667 (8%; 95%CI 6-11) and implant exposure in 120/1651 (6%; 95% CI 4-9).

CONCLUSION: PEEK appears to have the lowest risk of cranioplasty revision, but further research is required to determine the optimal material.

Surgery versus radiosurgery for facial nerve schwannoma

J Neurosurg 135:542–553, 2021

Intracranial facial nerve schwannomas (FNS) requiring treatment are frequently recommended for surgery or stereotactic radiosurgery (SRS). The objective of this study was to compare facial nerve function outcomes between these two interventions for FNS via a systematic review and meta-analysis.

METHODS A search of the Ovid EMBASE, PubMed, SCOPUS, and Cochrane databases from inception to July 2019 was conducted following PRISMA guidelines. Articles were screened against prespecified criteria. Facial nerve out- comes were classified as improved, stabilized, or worsened by last follow-up. Incidence was pooled by random-effects meta-analysis of proportions.

RESULTS Thirty-three articles with a pooled cohort of 519 patients with FNS satisfied all criteria. Twenty-five articles described operative outcomes in 407 (78%) patients; 10 articles reported SRS outcomes in 112 (22%). In the surgical cohort, facial nerve function improved in 23% (95% CI 15%–32%), stabilized in 41% (95% CI 32%–50%), and worsened in 30% (95% CI 21%–40%). In the SRS cohort, facial nerve function was improved in 20% (95% CI 9%–34%), stable in 66% (95% CI 54%–78%), and worsened in 9% (95% CI 3%–16%). Compared with SRS, microsurgery was associated with a significantly lower incidence of stable facial nerve function (p < 0.01) and a significantly higher incidence of wors- ened facial nerve function (p < 0.01). Tumor progression and complication rates were comparable. Outcome certainty assessments were very low to moderate for all parameters.

CONCLUSIONS Unfavorable facial nerve function outcomes are associated with surgical treatment of intracranial FNS, whereas stable facial nerve function outcomes are associated with SRS. Therefore, SRS should be recommended to patients with FNS who require treatment, and surgery should be reserved for patients with another indication, such as decompression of the brainstem. Further study is required to definitively optimize and validate management strategies for these rare skull base tumors.

Machine Learning for the Prediction of Molecular Markers in Glioma on Magnetic Resonance Imaging: A Systematic Review and Meta-Analysis

Neurosurgery 89:31–44, 2021

Molecular characterization of glioma has implications for prognosis, treatment planning, and prediction of treatment response. Current histopathology is limited by intratumoral heterogeneity and variability in detection methods. Advances in computational techniques have led to interest in mining quantitative imaging features to noninvasively detect genetic mutations.

OBJECTIVE: To evaluate the diagnostic accuracy of machine learning (ML) models in molecular subtyping gliomas on preoperative magnetic resonance imaging (MRI).

METHODS: A systematic search was performed following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines to identify studies up to April 1, 2020. Methodological quality of studies was assessed using the Quality Assessment for Diagnostic Accuracy Studies (QUADAS)-2. Diagnostic performance estimates were obtained using a bivariate model and heterogeneity was explored using metaregression.

RESULTS: Forty-four original articles were included. The pooled sensitivity and specificity for predicting isocitrate dehydrogenase (IDH) mutation in training datasets were 0.88 (95% CI 0.83-0.91) and 0.86 (95% CI 0.79-0.91), respectively, and 0.83 to 0.85 in validation sets. Use of data augmentation and MRI sequence type were weakly associated with heterogeneity. Both O6-methylguanine-DNA methyltransferase (MGMT) gene promoter methylation and 1p/19q codeletion could be predicted with a pooled sensitivity and specificity between 0.76 and 0.83 in training datasets.

CONCLUSION: ML application to preoperative MRI demonstrated promising results for predicting IDHmutation, MGMT methylation, and 1p/19q codeletion in glioma. Optimized ML models could lead to a noninvasive, objective tool that captures molecular information important for clinical decisionmaking. Future studies should use multicenter data, external validation and investigate clinical feasibility of ML models.

The endoscope-assisted supraorbital “keyhole” approach for anterior skull base meningiomas: an updated meta-analysis

Acta Neurochirurgica (2021) 163:661–676

The gold-standard treatment for symptomatic anterior skull base meningiomas is surgical resection. The endoscope-assisted supraorbital “keyhole” approach (eSKA) is a promising technique for surgical resection of olfactory groove (OGM) and tuberculum sellae meningioma (TSM) but has yet to be compared with the microscopic transcranial (mTCA) and the expanded endoscopic endonasal approach (EEA) in the context of existing literature.

Methods An updated study-level meta-analysis on surgical outcomes and complications of OGM and TSM operated with the eSKA, mTCA, and EEA was conducted using random-effect models.

Results A total of 2285 articles were screened, yielding 96 studies (2191 TSM and 1510 OGM patients). In terms of effective- ness, gross total resection incidence was highest in mTCA (89.6% TSM, 91.1% OGM), followed by eSKA (85.2% TSM, 84.9% OGM) and EEA (83.9% TSM, 82.8% OGM). Additionally, the EEA group had the highest incidence of visual improvement (81.9% TSM, 54.6% OGM), followed by eSKA (65.9% TSM, 52.9% OGM) and mTCA (63.9% TSM, 45.7% OGM). However, in terms of safety, the EEA possessed the highest cerebrospinal fluid leak incidence (9.2% TSM, 14.5% OGM), compared with eSKA (2.1% TSM, 1.6% OGM) and mTCA (1.6% TSM, 6.5% OGM). Finally, mortality and intraoperative arterial injury were 1% or lower across all subgroups.

Conclusions: In the context of diverse study populations, the eSKA appeared not to be associated with increased adverse outcomes when compared with mTCA and EEA and offered comparable effectiveness. Case-selection is paramount in establishing a role for the eSKA in anterior skull base tumours.

 

Surgical management for large vestibular schwannomas: a systematic review, meta-analysis, and consensus statement on behalf of the EANS skull base section

Acta Neurochir (2020) 162:2595–2617

The optimal management of large vestibular schwannomas continues to be debated. We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of this problem from a European perspective.

Material and methods A systematic review of MEDLINE database, in compliance with the PRISMA guidelines, was performed. A subgroup analysis screening all surgical series published within the last 20 years (January 2000 to March 2020) was performed. Weighted summary rates for tumor resection, oncological control, and facial nerve preservation were determined using metaanalysis models. This data along with contemporary practice patterns were discussed within the task force to generate consensual recommendations regarding preoperative evaluations, optimal surgical strategy, and follow-up management.

Results Tumor classification grades should be systematically used in the perioperative management of patients, with large vestibular schwannomas (VS) defined as > 30 mm in the largest extrameatal diameter. Grading scales for pre- and postoperative hearing (AAO-HNS or GR) and facial nerve function (HB) are to be used for reporting functional outcome. There is a lack of consensus to support the superiority of any surgical strategy with respect to extent of resection and use of adjuvant radiosurgery. Intraoperative neuromonitoring needs to be routinely used to preserve neural function. Recommendations for postoperative clinico-radiological evaluations have been elucidated based on the surgical strategy employed.

Conclusion The main goal of management of large vestibular schwannomas should focus on maintaining/improving quality of life (QoL), making every attempt at facial/cochlear nerve functional preservation while ensuring optimal oncological control, thereby allowing to meet patient expectations. Despite the fact that this analysis yielded only a few Class B evidences and mostly expert opinions, it will guide practitioners to manage these patients and form the basis for future clinical trials.

Keywords

Efficacy and safety of gamma knife radiosurgery for posterior cranial fossa meningioma

Neurosurgical Review (2020) 43:1089–1099

The management of posterior cranial fossa meningioma [PCFM] is challenging and many neurosurgeons advise gamma knife radiosurgery [GKRS] as a modality for its upfront or adjuvant treatment. Due to the varying radiosurgical response based on lesion location, tumor biology, and radiation dosage, we performed a pioneer attempt in doing a systematic review analyzing the treatment efficacy and safety profile of GKRS for PCFM based on current literature.

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses [PRISMA] guidelines. A thorough literature search was conducted on PubMed, Web of science, and Cochrane data base; articles were selected systematically based on PRISMA protocol, reviewed completely, and relevant data was summarized and discussed.

A total of 18 publications pertaining to GKRS for PCFM were included with a pooled sample size of 2131 patients. The median pre-GKRS tumor volume ranged from 2.28 to 10.5 cm [3]. Primary GKRS was administered in 61.1% of the pooled study cohorts, adjuvant treatment in 32.9%, and salvage therapy in 6.5% patients. Majority of the meningiomas were WHO grade 1 tumors (99.7%). The pooled mean marginal dose in the studies was 13.6 Gy (range 12–15.2 Gy) while the mean of maximum doses was 28.6 Gy (range 25–35 Gy). Most studies report an excellent radiosurgical outcome including the tumor control rate and the progression-free survival [PFS] of over 90%. The tumor control, PFS, and adverse radiation effect [ARE] rates in author’s series were 92.3%, 91%, and 9.6%, respectively. The favorable radiosurgical outcome depends on multiple factors such as small tumor volume, absence of previous radiotherapy, tumor location, elderly patients, female gender, longer time from symptom onset, and decreasing maximal dose.

GKRS as primary or adjuvant treatment modality needs to be considered as a promising management strategy for PCFM in selected patients in view of the growing evidence of high tumor control rate, improved neurological functions, and low incidence of ARE. The use of multiple isocenters, 3-D image planning, and limit GKRS treatment to tumors less than 3.5 cm help to avoid complications and achieve the best results. The treatment decisions in PCFM cases must be tailored and should consider the factors such as radiological profile, symptom severity, performance level, and patient preference for a good outcome.

Occlusion Rate and Visual ComplicationsWith Flow-Diverter Stent Placed Across the Ophthalmic Artery’s Origin for Carotid-Ophthalmic Aneurysms: A Meta-Analysis

Neurosurgery 86:455–463, 2020

Flow-diverter stents (FDSs) have recently gained acceptance for the treatment of intracranial aneurysms, especially for carotid-ophthalmic aneurysms (COAs). However, complications have been reported after coverage of side branches, especially the ophthalmic artery (OA).

OBJECTIVE: To evaluate, through a meta-analysis, the occlusion rate, and the ophthalmic complications after treatment of COA by FDS.

METHODS:We reviewed on MEDLINE via PubMed, Embase via Ovid, and Cochrane central database via CENTRAL.We included all case serieswith at least 15 patients and clinical trials about flow diversion of aneurysms close to the OA’s origin. Among these studies, we only included articles with aneurysm occlusion rate and rate of new ophthalmic symptoms.

RESULTS: We included 16 studies with 913 COA treated by FDSs and covering the OA with a mean follow-up of 16.4 mo. The random-effect modeling analysis concerning the overall rate of new ophthalmic complications, after FDS deployment covering the OA, was 3.0% (CI95% 1.0-6.0). There was medium-high heterogeneity in the study reports P < .01, I2 = 70.2% [50.4%; 82.1%]. We were not able to statistically explain this heterogeneity with the performed analysis, which could be related to the design of the included studies. We found an overall aneurysm occlusion rate of 85.0% (95% CI 80.0-89.0).

CONCLUSION: Our meta-analysis found a high aneurysm occlusion rate (85%) and low rate of iatrogenic visual complications, with only 3.0% of new visual symptoms, after treatment of COA by FDS.

Subperiosteal versus subdural drainage after burr hole evacuation of chronic subdural hematoma: systematic review and meta-analysis

Acta Neurochirurgica (2020) 162:489–498

The evidence for subperiosteal drainage (SPD) versus subdural drainage (SDD) in chronic subdural hematoma (CSDH) remains controversial, and most surgeons prefer to use SDD over SPD.We aimto assess the latest evidence on the use of SPD compared to SDD in patients with CSDH undergoing burr hole evacuation.

Methods We performed a systematic literature search on topics that assesses the use of SPD compared to SDD in patients with CSDH up until November 2019 from PubMed, EuropePMC, Cochrane Central Database, ScienceDirect, ProQuest, and ClinicalTrials.gov. The primary outcome was recurrent CSDH, and the secondary outcomes were mortality, surgical morbidities, and modified Rankin Score (mRS).

Results There were a total of 3241 subjects from 10 studies. SPD was shown to reduce recurrent CSDH (OR 0.66 [0.52, 0.84], p < 0.001; I2: 17%, p = 0.30) compared to SDD. Recurrent CSDH was lower in SPD group in subgroup analysis at 3-months (OR 0.63 [0.49, 0.81]; I2: 68%, p = 0.04) and 6-months (OR 0.66 [0.51, 0.85], p = 0.001; I2: 77%, p = 0.01) follow-up. However, there was no difference in CSDH recurrence upon subgroup analysis of RCTs. Similar mortality was demonstrated between SPD and SDD group (p = 0.13). The occurrence of parenchymal injury/new neurological deficit was significantly lower in SPD group (OR 0.26 [0.14, 0.51], p < 0.001; I2: 49%, p = 0.08). The rate of seizure, (p = 0.57), postoperative bleeding (p = 0.29), and infection (p = 0.25) were shown to be similar in both SPD and SDD group. Overall, the rate of surgical morbidity was significantly lower in SPD group (OR 0.61 [0.44, 0.85], p = 0.003; I2: 16%, p = 0.25). mRS at the end of follow-up was similar in SPD and SDD group (p = 0.12).

Conclusion SPD was associated with less CSDH recurrence, but similar rate of mortality, seizures, postoperative bleeding, and infections compared to SDD. The rate of parenchymal injury/new neurological deficit was lower in the SPD group.

Pain Outcomes Following Microvascular Decompression for Drug-Resistant Trigeminal Neuralgia: A Systematic Review and Meta-Analysis

Neurosurgery, Volume 86, Issue 2, February 2020, Pages 182–190

Microvascular decompression (MVD) is a potentially curative surgery for drug-resistant trigeminal neuralgia (TN). Predictors of pain freedom after MVD are not fully understood. OBJECTIVE: To describe rates and predictors for pain freedom following MVD.

METHODS: Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, PubMed, Cochrane Library, and Scopus were queried for primary studies examining pain outcomes after MVD for TN published between 1988 and March 2018. Potential biases were assessed for included studies. Pain freedom (ie, Barrow Neurological Institute score of 1) at last follow-up was the primary outcome measure. Variables associated with pain freedom on preliminary analysis underwent formal meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for possible predictors.

RESULTS: Outcome data were analyzed for 3897 patients from 46 studies (7 prospective, 39 retrospective). Overall, 76.0% of patients achieved pain freedom afterMVD with amean follow-up of 1.7 ± 1.3 (standard deviation) yr. Predictors of pain freedom on meta-analysis using random effectsmodels included (1) disease duration≤5 yr (OR=2.06, 95% CI=1.08- 3.95); (2) arterial compression over venous or other (OR = 3.35, 95% CI = 1.91-5.88); (3) superior cerebellar artery involvement (OR = 2.02, 95% CI = 1.02-4.03), and (4) type 1 Burchiel classification (OR = 2.49, 95% CI = 1.32-4.67).

CONCLUSION: Approximately three-quarters of patients with drug-resistant TN achieve pain freedom after MVD. Shorter disease duration, arterial compression, and type 1 Burchiel classification may predict more favorable outcome. These results may improve patient selection and provider expectations.

Safety of Outpatient Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

Neurosurgery 86:30–45, 2020

Anterior cervical discectomy and fusion (ACDF) is being increasingly offered on an outpatient basis. However, the safety profile of outpatient ACDF remains poorly defined.

OBJECTIVE: To review the medical literature on the safety of outpatient ACDF.

METHODS: We systematically reviewed the literature for articles published before April 1, 2018, describing outpatient ACDF and associated complications, including incidence of reoperation, stroke, thrombolytic events, dysphagia, hematoma, and mortality. A random-effects analysis was performed comparing complications between the inpatient and outpatient groups.

RESULTS: We identified 21 articles that satisfied the selection criteria, of which 15 were comparative studies. Most of the existing studies were retrospective, with a lack of level I or II studies on this topic. We found no statistically significant difference between inpatient and outpatient ACDF in overall complications, incidence of stroke, thrombolytic events, dysphagia, and hematoma development. However, patients undergoing outpatient ACDF had lower reported reoperation rates (P < .001), mortality (P < .001), and hospitalization duration (P < .001).

CONCLUSION: Our meta-analysis indicates that there is a lack of high level of evidence studies regarding the safety of outpatient ACDF. However, the existing literature suggests that outpatient ACDF can be safe, with low complication rates comparable to inpatient ACDF in well-selected patients. Patients with advanced age and comorbidities such as obesity and significant myelopathy are likely not suitable for outpatient ACDF. Spine surgeons must carefully evaluate each patient to decide whether outpatient ACDF is a safe option. Higher quality, large prospective randomized control trials are needed to accurately demonstrate the safety profile of outpatient ACDF.

Complications Associated with Surgery for Thoracic Disc Herniation: A Systematic Review and Network Meta-Analysis

World Neurosurgery Volume 132, December 2019, Pages 334-342

A systematic review and network meta-analysis (Prospero ID CRD42018106936) were performed.

Objective: The selection of the appropriate surgical approach for the management of thoracic disc herniation (TDH) is often challenging because of the frequency and variability of the associated complications. We evaluated the safety of the surgical approaches for TDH by estimating the mortality (Q1) and morbidity (Q2), and frequency of the most common complications (Q3).

Methods: We searched the medical literature for randomized controlled trials and observational studies reporting on the management of TDH. Postoperative complications were the outcome of interest. The absolute and relative risk estimates, along with the rank probability scores, were estimated for each approach, through a network meta-analysis. The results were read in the light of the quality of the available evidence.

Results: Fifteen studies with a total of 1036 patients fulfilled our eligibility criteria. Three deaths were reported. The overall morbidity was as high as 29%, largely attributed to medical (21%; 95% confidence interval [CI], 10%–38%), surgical site (11%; 95% CI, 5%–22%), cerebrospinal fluid–related (8%; 95% CI, 3%–8%), and neurologic complications (5%; 95% CI, 1%–24%). The anterior and lateral approaches were associated with a higher risk for medical and surgical complications compared with the posterolateral approach.

Conclusions: Surgery for TDH is associated with minimal mortality but significant morbidity, with large variations among the available approaches. An understanding of the perioperative complications rates is important to develop complication avoidance strategies and to aid accurate patient-to-doctor communication.

Outcomes of Retreatment for Intracranial Aneurysms—A Meta-Analysis

Neurosurgery. 2019 Dec 1;85(6):750-761

Long-term results from the International Subarachnoid Hemorrhage Trial (ISAT) and Barrow Ruptured Aneurysm Trial (BRAT) indicate considerably higher retreatment rates for aneurysms treated with coiling compared to clipping, but do not report the outcome of retreatment.

OBJECTIVE: To evaluate retreatment related outcomes.

METHODS: A meta-analysis in accordance with PRISMA guidelines was conducted using Medline search engines PubMed and EMBASE to identify articles describing outcomes after retreatment for intracranial aneurysms. Pooled prevalence rates for complete occlusion rate and mortality were calculated. Outcomes of different treatment and retreatment combinations were not compared because of indication bias.

RESULTS: Twenty-five articles that met the inclusion criteria were included in the metaanalysis. Surgery after coiling had a pooled complete occlusion rate of 91.2% (95% confidence interval [CI]: 87.0-94.1) and a pooled mortality rate of 5.6% (95% CI: 3.7-8.3). Coiling after coiling had a pooled complete occlusion rate of 51.3% (95% CI: 22.1-78.0) and a pooled mortality rate of 0.8% (95% CI: 0.15-3.7). Surgery after surgery did not provide a pooled estimate for complete occlusion as only one study was identified but had a pooled mortality rate of 5.9% (95% CI: 3.1-11.2). Coiling after surgery had a pooled complete occlusion rate of 56.1% (95% CI: 11.4-92.7) and a pooled mortality rate of 9.3% (95% CI: 4.1- 19.9). All pooled incidence rates were produced using random-effect models.

CONCLUSION: Surgical retreatment was associated with a high complete occlusion rate but considerable mortality. Conversely, endovascular retreatment was associated with low mortality but also a low complete occlusion rate.

Outcomes of endoscopic discectomy compared with open microdiscectomy and tubular microdiscectomy for lumbar disc herniations: a meta-analysis

J Neurosurg Spine 31:802–815, 2019

Endoscopic discectomy (ED) has been advocated as a less-invasive alternative to open microdiscectomy (OM) and tubular microdiscectomy (TM) for lumbar disc herniations, with the potential to decrease postoperative pain and shorten recovery times. Large-scale, objective comparisons of outcomes between ED, OM, and TM, however, are lacking. The authors’ objective in this study was to conduct a meta-analysis comparing outcomes of ED, OM, and TM.

METHODS The PubMed database was searched for articles published as of February 1, 2019, for comparative studies reporting outcomes of some combination of ED, OM, and TM. A meta-analysis of outcome parameters was performed assuming random effects.

RESULTS Twenty-six studies describing the outcomes of 2577 patients were included. Estimated blood loss was significantly higher with OM than with both TM (p = 0.01) and ED (p < 0.00001). Length of stay was significantly longer with OM than with ED (p < 0.00001). Return to work time was significantly longer in OM than with ED (p = 0.001). Postoperative leg (p = 0.02) and back (p = 0.01) VAS scores, and Oswestry Disability Index scores (p = 0.006) at latest follow-up were significantly higher for OM than for ED. Serum creatine phosphokinase (p = 0.02) and C-reactive protein (p < 0.00001) levels on postoperative day 1 were significantly higher with OM than with ED.

CONCLUSIONS Outcomes of TM and OM for lumbar disc herniations are largely equivalent. While this analysis demonstrated that several clinical variables were significantly improved in patients undergoing ED when compared with OM, the magnitude of many of these differences was small and of uncertain clinical relevance, and several of the included studies were retrospective and subject to a high risk of bias. Further high-quality prospective studies are needed before definitive conclusions can be drawn regarding the comparative efficacy of the various surgical treatments for lumbar disc herniations.

 

A Meta-Analysis of Risk Factors for the Formation of de novo Intracranial Aneurysms

Neurosurgery, Volume 85 (4) 2019, 454–465

Understanding the risk factors for the formation of de novo intracranial aneurysms (IAs) is important for patients who have ever suffered a cerebral aneurysm.

OBJECTIVE: To estimate the risk factors for the development of a de novo IA to identify which patients need more aggressive surveillance after aneurysm treatment.

METHODS: We followed the preferred reporting items for systematic reviews and metaanalyses guidelines and searched the PubMed, CENTRAL, EMBASE, and LILACS databases using the key words cerebral aneurysms, de novo, IAs, risk factors combined using and/or. The search was performed in July 2017.We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using RevMan 5.3 (Cochrane, London, United Kingdom) to evaluate risk factors. Statistical significance was set at P < .05.

RESULTS: The analysis included 14 studies involving 6389 patients, of whom 197 patients had de novo IAs. The main risk factors for formation included sex (OR = 1.82, 95% CI [1.30,2.56], P = .0005, female vs male), age <40 yr (OR = 2.96, 95% CI [1.76,4.96], P < .0001), family history (OR = 2.05, 95% CI [1.07,3.93], P = .03), smoking history (OR = 2.73, 95% CI [1.81,4.12], P < .0001), and multiple saccular intracranial aneurysms (sIAs) at first diagnosis (OR = 2.10, 95% CI [1.12,3.91], P = .02), internal carotid artery (ICA) as the initial site (OR = 2.58, 95% CI [1.43,4.68], P = .002). Heterogeneous analysis showed that these I 2 were less than 50% and the results were reliable.

CONCLUSION: Observational evidence identified multiple clinical and anatomic risk factors for the formation of de novo IAs, including female sex, age <40 yr, family history, smoking history, multiple sIAs at first diagnosis, and IC as the initial site. More aggressive long-term angiographic follow-up with digital subtraction angiography, computed tomography angiography, or magnetic resonance angiography is recommended for these patients.

Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

J Neurosurg 131:1024–1036, 2019

Different CSF diversion procedures (ventriculoperitoneal, ventriculoatrial, and lumboperitoneal shunting) have been utilized for the treatment of idiopathic normal pressure hydrocephalus. More recently, endoscopic third ventriculostomy has been suggested as a reasonable alternative in some studies. The purpose of this study was to perform a systematic review and meta-analysis to assess overall rates of favorable outcomes and adverse events for each of these treatments. An additional objective was to determine the outcomes and complication rates in relation to the type of valve utilized (fixed vs programmable).

METHODS Multiple databases (PubMed, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus) were searched for studies involving patients with idiopathic ventriculomegaly, no secondary cause of hydrocephalus, opening pressure < 25 mm Hg on high-volume tap or drainage trial, and age > 60 years. Outcomes included the proportion of patients who showed improvement in gait, cognition, and bladder function. Adverse events considered in the analysis included postoperative ischemic/hemorrhagic complications, subdural fluid collections, seizures, need for revision surgery, and infection.

RESULTS A total of 33 studies, encompassing 2461 patients, were identified. More than 75% of patients experienced improvement after shunting, without significant differences among the different techniques utilized. Overall, gait improvement was observed in 75% of patients, cognitive function improvement in more than 60%, and improvement of incontinence in 55%. Adjustable valves were associated with a reduction in revisions (12% vs 32%) and subdural collections (9% vs 22%) as compared to fixed valves.

CONCLUSIONS Outcomes did not differ significantly among different CSF diversion techniques, and overall improvement was reported in more than 75% of patients. The use of programmable valves decreased the incidence of revision surgery and of subdural collections after surgery, potentially justifying the higher initial cost associated with these valves.

Correlation between glioma location and preoperative seizures: a systematic review and meta-analysis

Epilepsy is a common manifestation of glioma patients and negatively impacts on quality of life and neurocognitive function. The risk of preoperative seizures in patients with glioma is currently under discussion.

We aimed to evaluate the relationship between tumor locations in the cerebrum and preoperative seizures in patients with glioma. PubMed, EMBASE, Web of Science, China Biology Medicine, and the Cochrane Library were systematically searched from inception to July 15, 2017, for original studies including reports of preoperative seizures in patients with gliomas in different brain regions. The pooled odds ratio (OR) and 95% confidence interval (CI) of the meta-analysis for preoperative seizure risk stratified by cerebrum regions were calculated. The quality of evidence was assessed per outcome, using the approach of the Grades of Recommendation, Assessment, Development and Evaluation.

Overall, 4323 participants in 16 population-based studies were included in this meta-analysis. The meta-analysis indicated that gliomas in the frontal lobe (OR = 1.51, 95% CI = 1.09–2.09, P = 0.013) were associated with a higher risk for preoperative seizure compared to occipital lobe involved (OR = 0.53, 95% CI = 0.32–0.88, P = 0.014). Regarding the other three lobe involved gliomas, no difference was found between the incidence of preoperative seizures and tumor location.

Current limited data suggest that frontal gliomas were associated with a higher risk of preoperative seizures, while gliomas in the occipital lobe were associated with a lower seizure risk. Further RCT studies recruiting larger sample sizes are required to validate these results and guide clinical practice.

Surgical management of camptocormia in Parkinson’s disease: systematic review and meta-analysis

J Neurosurg 131:368–375, 2019

Camptocormia is a potentially debilitating condition in the progression of Parkinson’s disease (PD). It is described as an abnormal forward flexion while standing that resolves when lying supine. Although the condition is relatively common, the underlying pathophysiology and optimal treatment strategy are unclear. In this study, the authors systematically reviewed the current surgical management strategies for camptocormia.

METHODS PubMed was queried for primary studies involving surgical intervention for camptocormia in PD patients. Studies were excluded if they described nonsurgical interventions, provided only descriptive data, or were case reports. Secondarily, data from studies describing deep brain stimulation (DBS) to the subthalamic nuclei were extracted for potential meta-analysis. Variables showing correlation to improvement in sagittal plane bending angle (i.e., the vertical angle caused by excessive kyphosis) were subjected to formal meta-analysis.

RESULTS The query resulted in 9 studies detailing treatment of camptocormia: 1 study described repetitive trans-spinal magnetic stimulation (rTSMS), 7 studies described DBS, and 1 study described deformity surgery. Five studies were included for meta-analysis. The total number of patients was 66. The percentage of patients with over 50% decrease in sagittal plane imbalance with DBS was 36.4%. A duration of camptocormia of 2 years or less was predictive of better outcomes (OR 4.15).

CONCLUSIONS Surgical options include transient, external spinal stimulation; DBS targeting the subthalamic nuclei; and spinal deformity surgery. Benefit from DBS stimulation was inconsistent. Spine surgery corrected spinal imbalance but was associated with a high complication rate.

Global hydrocephalus epidemiology and incidence: systematic review and meta-analysis

J Neurosurg 130:1065–1079, 2019

Hydrocephalus is one of the most common brain disorders, yet a reliable assessment of the global burden of disease is lacking. The authors sought a reliable estimate of the prevalence and annual incidence of hydrocephalus worldwide.

METHODS The authors performed a systematic literature review and meta-analysis to estimate the incidence of congenital hydrocephalus by WHO region and World Bank income level using the MEDLINE/PubMed and Cochrane Database of Systematic Reviews databases. A global estimate of pediatric hydrocephalus was obtained by adding acquired forms of childhood hydrocephalus to the baseline congenital figures using neural tube defect (NTD) registry data and known proportions of posthemorrhagic and postinfectious cases. Adult forms of hydrocephalus were also examined qualitatively.

RESULTS Seventy-eight articles were included from the systematic review, representative of all WHO regions and each income level. The pooled incidence of congenital hydrocephalus was highest in Africa and Latin America (145 and 316 per 100,000 births, respectively) and lowest in the United States/Canada (68 per 100,000 births) (p for interaction < 0.1). The incidence was higher in low- and middle-income countries (123 per 100,000 births; 95% CI 98–152 births) than in high-income countries (79 per 100,000 births; 95% CI 68–90 births) (p for interaction < 0.01). While likely representing an underestimate, this model predicts that each year, nearly 400,000 new cases of pediatric hydrocephalus will develop worldwide. The greatest burden of disease falls on the African, Latin American, and Southeast Asian regions, accounting for three-quarters of the total volume of new cases. The high crude birth rate, greater proportion of patients with postinfectious etiology, and higher incidence of NTDs all contribute to a case volume in low- and middle-income countries that outweighs that in high-income countries by more than 20-fold. Global estimates of adult and other forms of acquired hydrocephalus are lacking.

CONCLUSIONS For the first time in a global model, the annual incidence of pediatric hydrocephalus is estimated. Low and middle-income countries incur the greatest burden of disease, particularly those within the African and Latin American regions. Reliable incidence and burden figures for adult forms of hydrocephalus are absent in the literature and warrant specific investigation. A global effort to address hydrocephalus in regions with the greatest demand is imperative to reduce disease incidence, morbidity, mortality, and disparities of access to treatment.

The impact of adding posterior instrumentation to transpsoas lateral fusion

J Neurosurg Spine 30:211–221, 2019

Transpsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumentation posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors’ knowledge, the literature on comparison of the two approaches is sparse.

METHODS The authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guidelines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP).

RESULTS A total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confidence interval [CI] 0.04–0.11) compared to TPP (0.03, 95% CI 0.01–0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10–0.26) compared to TPP (0.03, 95% CI 0.00–0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient deficits were found to be comparable between the two groups.

CONCLUSIONS These results appear to suggest that addition of posterior instrumentation to transpsoas fusion is associated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique.