Author: cba

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Nasopharyngeal muscle patch for the management of internal carotid artery injury in endoscopic endonasal surgery

J Neurosurg 133:1382–1387, 2020

Injury to the internal carotid artery (ICA) is the most critical complication of endoscopic endonasal skull base surgery. Packing with a crushed muscle graft at the injury site has been an effective management technique to control bleeding without ICA sacrifice. Obtaining the muscle graft has typically required access to another surgical site, however. To address this concern, the authors investigated the application of an endonasally harvested longus capitis muscle patch for the management of ICA injury.

METHODS One colored silicone-injected anatomical specimen was dissected to replicate the surgical access to the nasopharynx and the stepwise dissection of the longus capitis muscle in the nasopharynx. Two representative cases were selected to illustrate the application of the longus capitis muscle patch and the relevance of clinical considerations.

RESULTS A suitable muscle graft from the longus capitis muscle could be easily and quickly harvested during endoscopic endonasal skull base surgery. In the illustrative cases, the longus capitis muscle patch was successfully used for secondary prevention of pseudoaneurysm formation following primary bleeding control on the site of ICA injury.

CONCLUSIONS Nasopharyngeal harvest of a longus capitis muscle graft is a safe and practical method to manage ICA injury during endoscopic endonasal surgery.

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Lateral supra-cerebellar infra-tentorial approach for P2-P3 junction cerebral aneurysms

Acta Neurochirurgica (2020) 162:2767–2772

P2-P3 junction aneurysms are challenging to treat surgically because of their frequent complex morphology and their location deep in close proximity to the midbrain. The sub-temporal route requires significant retraction of the temporal lobe in addition to potential injury to the vein of Labbe.

We describe the technique for treating such aneurysms via a lateral supra-cerebellar infratentorial (LSCIT) approach, which eliminates manipulation of the temporal lobe.

Method Cadaveric dissection provided comprehensive understanding of relevant anatomy. Intraoperative video shows clipping of the aneurysm using a LSCIT approach.

Conclusion LSCIT approach allows safe clipping of P2-P3 aneurysms with minimal brain manipulation.

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Impact of facility type and volume in low-grade glioma outcomes

J Neurosurg 133:1313–1323, 2020

The object of this study was to investigate the impact of facility type (academic center [AC] vs non-AC) and facility volume (high-volume facility [HVF] vs low-volume facility [LVF]) on low-grade glioma (LGG) outcomes.

METHODS This retrospective cohort study included 5539 LGG patients (2004–2014) from the National Cancer Database. Patients were categorized by facility type and volume (non-AC vs AC, HVF vs LVF). An HVF was defined as the top 1% of facilities according to the number of annual cases. Outcomes included overall survival, treatment receipt, and postoperative outcomes. Kaplan-Meier and Cox proportional-hazards models were applied. The Heller explained relative risk was computed to assess the relative importance of each survival predictor.

RESULTS Significant survival advantages were observed at HVFs (HR 0.67, 95% CI 0.55–0.82, p < 0.001) and ACs (HR 0.84, 95% CI 0.73–0.97, p = 0.015), both prior to and after adjusting for all covariates. Tumor resection was 41% and 26% more likely to be performed at HVFs vs LVFs and ACs vs non-ACs, respectively. Chemotherapy was 40% and 88% more frequently to be utilized at HVFs vs LVFs and ACs vs non-ACs, respectively. Prolonged length of stay (LOS) was decreased by 42% and 24% at HVFs and ACs, respectively. After tumor histology, tumor pattern, and codeletion of 1p19q, facility type and surgical procedure were the most important contributors to survival variance. The main findings remained consistent using propensity score matching and multiple imputation.

CONCLUSIONS This study provides evidence of survival benefits among LGG patients treated at HVFs and ACs. An increased likelihood of undergoing resections, receiving adjuvant therapies, having shorter LOSs, and the multidisciplinary environment typically found at ACs and HVFs are important contributors to the authors’ finding.

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Outcomes following discectomy for lumbar disc herniation in patients with substantial back pain

J Neurosurg Spine 33:623–626, 2020

Patients with lumbar disc herniation (LDH) typically present with lower-extremity radiculopathy. However, there are patients who have concomitant substantial back pain (BP) and are considered candidates for fusion. The purpose of this study was to determine if patients with LDH and substantial BP improve with discectomy alone.

METHODS The DaneSpine database was used to identify 2399 patients with LDH and baseline BP visual analog scale (VAS) scores ≥ 50 who underwent a lumbar discectomy at one of 3 facilities between June 2010 and December 2017. Standard demographic and surgical variables and patient-reported outcomes, including BP and leg pain (LP) VAS scores (0–100), Oswestry Disability Index (ODI), and European Quality of Life–5 Dimensions Questionnaire (EQ-5D) at baseline and 12 months postoperatively, were collected.

RESULTS A total of 1654 patients (69%) had 12-month data available, with a mean age of 48.7 years; 816 (49%) were male and the mean BMI was 27 kg/m2. At 12 months postoperatively, there were statistically significant improvements (p < 0.0001) in BP (72.6 to 36.9), LP (74.8 to 32.6), ODI (50.9 to 25.1), and EQ-5D (0.25 to 0.65) scores.

CONCLUSIONS Patients with LDH and LP and concomitant substantial BP can be counseled to expect improvement in their BP 12 months after surgery after a discectomy alone, as well as improvement in their LP.

 

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Diabetes Insipidus After Endoscopic Transsphenoidal Surgery

Neurosurgery 2020 DOI:10.1093/neuros/nyaa148

Diabetes insipidus (DI) is a recognized transient or permanent complication following transsphenoidal surgery (TSS) for pituitary tumors.

OBJECTIVE: To describe significant experience with the incidence of DI after TSS, identifying predictive characteristics and describing our diagnosis and management of postoperative DI.

METHODS: A retrospective analysis was performed of 700 patients who underwent endoscopic TSS for resection of pituitary adenoma (PA), Rathke cleft cyst (RCC), or craniopharyngioma. Inclusion criteria included at least 1 wk of follow-up for diagnosis of postoperative DI. Permanent DI was defined as DI symptoms and/or need for desmopressinmore than 1 yr postoperatively. All patients with at least 1 yr of follow-up (n=345) were included in analyses of permanent DI. Multivariable logistic regression models were constructed to identify predictors of transient or permanent postoperative DI.

RESULTS: The overall rate of any postoperative DI was 14.7% (103/700). Permanent DI developed in 4.6% (16/345). The median follow-up was 10.7mo (range: 0.2-136.6). Compared to patients with PA, patients with RCC (odds ratio [OR] = 2.2, 95% CI: 1.2-3.9; P = .009) and craniopharyngioma (OR = 7.0, 95% CI: 2.9-16.9; P ≤ .001) were more likely to develop postoperative DI. Furthermore, patients with RCC (OR = 6.1, 95% CI: 1.8-20.6; P = .004) or craniopharyngioma (OR = 18.8, 95% CI: 4.9-72.6; P ≤ .001) were more likely to develop permanent DI compared to those with PA.

CONCLUSION: Although transient DI is a relatively common complication of endoscopic and microscopic TSS, permanent DI is much less frequent. The underlying pathology is an important predictor of both occurrence and permanency of postoperative DI.

 

 

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Contemporary assessment of extent of resection in molecularly defined categories of diffuse low-grade glioma: a volumetric analysis

J Neurosurg 133:1291–1301, 2020

While the effect of increased extent of resection (EOR) on survival in diffuse infiltrating low-grade glioma (LGG) patients is well established, there is still uncertainty about the influence of the new WHO molecular subtypes. The authors designed a retrospective analysis to assess the interplay between EOR and molecular classes.

METHODS The authors retrospectively reviewed the records of 326 patients treated surgically for hemispheric WHO grade II LGG at Brigham and Women’s Hospital and Massachusetts General Hospital (2000–2017). EOR was calculated volumetrically and Cox proportional hazards models were built to assess for predictive factors of overall survival (OS), progression-free survival (PFS), and malignant progression–free survival (MPFS).

RESULTS There were 43 deaths (13.2%; median follow-up 5.4 years) among 326 LGG patients. Median preoperative tumor volume was 31.2 cm3 (IQR 12.9–66.0), and median postoperative residual tumor volume was 5.8 cm3 (IQR 1.1–20.5). On multivariable Cox regression, increasing postoperative volume was associated with worse OS (HR 1.02 per cm3; 95% CI 1.00–1.03; p = 0.016), PFS (HR 1.01 per cm3; 95% CI 1.00–1.02; p = 0.001), and MPFS (HR 1.01 per cm3; 95% CI 1.00–1.02; p = 0.035). This result was more pronounced in the worse prognosis subtypes of IDH-mutant and IDH-wildtype astrocytoma, for which differences in survival manifested in cases with residual tumor volume of only 1 cm3. In oligodendroglioma patients, postoperative residuals impacted survival when exceeding 8 cm3. Other significant predictors of OS were age at diagnosis, IDH-mutant and IDH-wildtype astrocytoma classes, adjuvant radiotherapy, and increasing preoperative volume.

CONCLUSIONS The results corroborate the role of EOR in survival and malignant transformation across all molecular subtypes of diffuse LGG. IDH-mutant and IDH-wildtype astrocytomas are affected even by minimal postoperative residuals and patients could potentially benefit from a more aggressive surgical approach.

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Diagnostic reliability of the Berlin classification for complex MCA aneurysms—usability in a series of only giant aneurysms

Acta Neurochirurgica (2020) 162:2753–2758

The main challenge of bypass surgery of complex MCA aneurysms is not the selection of the bypass type but the initial decision-making of how to exclude the affected vessel segment from circulation. To this end, we have previously proposed a classification for complexMCA aneurysms based on the preoperative angiography. The current study aimed to validate this new classification and assess its diagnostic reliability using the giant aneurysm registry as an independent data set.

Methods We reviewed the pretreatment neuroimaging of 51 patients with giant (> 2.5 cm) MCA aneurysms from 18 centers, prospectively entered into the international giant aneurysm registry. We classified the aneurysms according to our previously proposed Berlin classification for complex MCA aneurysms. To test for interrater diagnostic reliability, the data set was reviewed by four independent observers.

Results We were able to classify all 51 aneurysms according to the Berlin classification for complex MCA aneurysms. Eight percent of the aneurysm were classified as type 1a, 14% as type 1b, 14% as type 2a, 24% as type 2b, 33% as type 2c, and 8% as type 3. The interrater reliability was moderate with Fleiss’s Kappa of 0.419.

Conclusion The recently published Berlin classification for complex MCA aneurysms showed diagnostic reliability, independent of the observer when applied to the MCA aneurysms of the international giant aneurysm registry.

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Correlations between genomic subgroup and clinical features in a cohort of more than 3000 meningiomas

J Neurosurg 133:1345–1354, 2020

Recent large-cohort sequencing studies have investigated the genomic landscape of meningiomas, identifying somatic coding alterations in NF2, SMARCB1, SMARCE1, TRAF7, KLF4, POLR2A, BAP1, and members of the PI3K and Hedgehog signaling pathways. Initial associations between clinical features and genomic subgroups have been described, including location, grade, and histology. However, further investigation using an expanded collection of samples is needed to confirm previous findings, as well as elucidate relationships not evident in smaller discovery cohorts.

METHODS Targeted sequencing of established meningioma driver genes was performed on a multiinstitution cohort of 3016 meningiomas for classification into mutually exclusive subgroups. Relevant clinical information was collected for all available cases and correlated with genomic subgroup. Nominal variables were analyzed using Fisher’s exact tests, while ordinal and continuous variables were assessed using Kruskal-Wallis and 1-way ANOVA tests, respectively. Machine-learning approaches were used to predict genomic subgroup based on noninvasive clinical features.

RESULTS Genomic subgroups were strongly associated with tumor locations, including correlation of HH tumors with midline location, and non-NF2 tumors in anterior skull base regions. NF2 meningiomas were significantly enriched in male patients, while KLF4 and POLR2A mutations were associated with female sex. Among histologies, the results confirmed previously identified relationships, and observed enrichment of microcystic features among “mutation unknown” samples. Additionally, KLF4-mutant meningiomas were associated with larger peritumoral brain edema, while SMARCB1 cases exhibited elevated Ki-67 index. Machine-learning methods revealed that observable, noninvasive patient features were largely predictive of each tumor’s underlying driver mutation.

CONCLUSIONS Using a rigorous and comprehensive approach, this study expands previously described correlations between genomic drivers and clinical features, enhancing our understanding of meningioma pathogenesis, and laying further groundwork for the use of targeted therapies. Importantly, the authors found that noninvasive patient variables exhibited a moderate predictive value of underlying genomic subgroup, which could improve with additional training data. With continued development, this framework may enable selection of appropriate precision medications without the need for invasive sampling procedures.

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A Simple Flow Classification Parameter Can Discriminate Rupture Status in Intracranial Aneurysms

Neurosurgery 2020 DOI:10.1093/neuros/nyaa189

A simple dimensionless aneurysm number (An), which depends on geometry and flow pulsatility, was previously shown to distinguish the flow mode in intracranial aneurysms (IA): vortex mode with a dynamic vortex formation/evolution if An > 1, and cavity mode with a steady shear layer if An < 1.

OBJECTIVE: To hypothesize that An > 1 can distinguish rupture status because vortex mode is associated with high oscillatory shear index, which, in turn, is statistically associated with rupture.

METHODS: The above hypothesis is tested on a retrospective, consecutively collected database of 204 patient-specific IAs. The first 119 cases are assigned to training and the remainder to testing dataset. An is calculated based on the pulsatility index (PI) approximated either from the literature or solving an optimization problem (denoted as PI). Student’s t-test and logistic regression (LR) are used for hypothesis testing and data fitting, respectively.

RESULTS: An can significantly discriminate ruptured and unruptured status with 95% confidence level (P<.0001). An (using PI) and An (usingPI) significantly predict the ruptured IAs (for training dataset An: AUC = 0.85, An: AUC = 0.90, and for testing dataset An: sensitivity = 94%, specificity = 33%,An: sensitivity = 93.1%, specificity = 52.85%).

CONCLUSION: An > 1 predicts ruptured status. Unlike traditional hemodynamic parameters such as wall shear stress and oscillatory shear index, An has a physical threshold of one (does not depend on statistical analysis) and does not require time-consuming flow simulations. Therefore, An is a simple, practical discriminator of IA rupture status.

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Low-Grade Infection and Implant Failure Following Spinal Instrumentation

Neurosurgery 87:964–970, 2020

Spinal instrumentation can be associated with complications, including implant loosening. Hitherto, implant loosening has mainly been attributed to mechanical overload.

OBJECTIVE: To examine the role of low-grade infections as the cause of implant failure in suspected aseptic implant loosening following spinal instrumentation.

METHODS: A prospective single center observational study was performed. All patients who had revision surgery following spinal instrumentation between August 2015 and February 2018 were screened. Patients with revision surgery due to screw loosening on the computed tomograhy scan constituted the study group. Patients in which the screws where not loosened but removalwas performed for other reasons formed the comparison group. Intraoperative swabswere taken and sonicationwas performedwith the explanted material. Results of microbiological cultivation were analyzed.

RESULTS: A total of 59 patients were included in the study group and 34 in the comparison group. In the study group in 42.4% of the cultures a bacterium was detected, while in the comparison group only in 17.6%. 84%, and 83.3% of these germs were detected by sonication in the study and comparison group, respectively. The rate of positive cultures was significantly higher in the study group compared to the comparison group (P= .001). The most frequent bacterium cultivated in both groups was Propionibacterium acnes, followed by Staphylococcus species.

CONCLUSION: For patients with screw loosening a high level of suspicion for a low-grade infection should be raised. Cultures should be performed from the sonication fluid of the explanted devices in all patients with symptomatic screw loosening.

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Tailoring the surgical corridor to the basilar apex in the pretemporal transcavernous approach

Acta Neurochirurgica (2020) 162:2731–2741

The pretemporal transcavernous approach (PTA) provides optimal exposure and access to the basilar artery (BA); however, the PTA can be invasive when vital neurovascular structures are mobilized. The goal of this study was to evaluate mobilization strategies to tailor approaches to the BA.

Methods After an orbitozygomatic craniotomy, 10 sides of 5 cadaveric heads were used to assess the surgical access to the BA via the opticocarotid triangle (OCT), carotid-oculomotor triangle (COT), and oculomotor-tentorial triangle (OTT). Measurements were obtained, and morphometric analyses were performed for natural neurovascular positions and after each stepwise expansion maneuver. An imaginary line connecting the midpoints of the limbus sphenoidale and dorsum sellae was used as a reference to normalize the measurements of BA exposure and to facilitate the clinical applicability of this technique.

Results In the OCT, the exposed BA segment ranged from − 1 ± 3.9 to + 6 ± 2.0 mm in length in its natural position. In the COT, the accessible BA segment ranged from − 4 ± 2.3 to − 2 ± 3.0mmin length in its natural position. Via the OTT, the accessible BA segment ranged from − 7 ± 2.6 to − 5 ± 2.8 mm in length in its natural position. In the OCT, COT, and OTT, a posterior clinoidectomy extended the exposure down to − 6 ± 2.7, − 8 ± 2.5, and − 9 ± 2.9 mm, respectively.

Conclusions This study quantitatively evaluated the need for the expansion maneuvers in the PTA to reach BA aneurysms according to the patient’s anatomical characteristics.

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Aspirin associated with decreased rate of intracranial aneurysm growth

J Neurosurg 133:1478–1485, 2020

Aspirin has emerged as a potential agent in the prevention of rupture of intracranial aneurysms (IAs). In this study, the authors’ goal was to test if aspirin is protective against aneurysm growth in patients harboring multiple IAs ≤ 5 mm.

METHODS The authors performed a retrospective review of a prospectively maintained database covering the period July 2009 through January 2019. Patients’ data were included if the following criteria were met: 1) the patient harbored multiple IAs; 2) designated primary aneurysms were treated by surgical/endovascular means; 3) the remaining aneurysms were observed for growth; and 4) a follow-up period of at least 5 years after the initial treatment was available. Demographics, earlier medical history, the rupture status of designated primary aneurysms, aneurysms’ angiographic features, and treatment modalities were gathered.

RESULTS The authors identified 146 patients harboring a total of 375 IAs. At the initial encounter, 146 aneurysms were treated and the remaining 229 aneurysms (2–5 mm) were observed. During the follow-up period, 24 (10.48%) of 229 aneurysms grew. All aneurysms observed to grow later underwent treatment. None of the observed aneurysms ruptured. Multivariate analysis showed that aspirin was significantly associated with a decreased rate of growth (odds ratio [OR] 0.19, 95% confidence interval [CI] 0.05–0.63). Variables associated with an increased rate of growth included hypertension (OR 14.38, 95% CI 3.83–53.94), drug abuse (OR 11.26, 95% CI 1.21–104.65), history of polycystic kidney disease (OR 9.48, 95% CI 1.51–59.35), and subarachnoid hemorrhage at presentation (OR 5.91, 95% CI 1.83–19.09).

CONCLUSIONS In patients with multiple IAs, aspirin significantly decreased the rate of aneurysm growth over time. Additional prospective interventional studies are needed to validate these findings.

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The frontal longitudinal system as revealed through the fiber microdissection technique

J Neurosurg 133:1503–1515, 2020

The purpose of this study was to investigate the morphology, connectivity, and correlative anatomy of the longitudinal group of fibers residing in the frontal area, which resemble the anterior extension of the superior longitudinal fasciculus (SLF) and were previously described as the frontal longitudinal system (FLS).

METHODS Fifteen normal adult formalin-fixed cerebral hemispheres collected from cadavers were studied using the Klingler microdissection technique. Lateral to medial dissections were performed in a stepwise fashion starting from the frontal area and extending to the temporoparietal regions.

RESULTS The FLS was consistently identified as a fiber pathway residing just under the superficial U-fibers of the middle frontal gyrus or middle frontal sulcus (when present) and extending as far as the frontal pole. The authors were able to record two different configurations: one consisting of two distinct, parallel, longitudinal fiber chains (13% of cases), and the other consisting of a single stem of fibers (87% of cases). The fiber chains’ cortical terminations in the frontal and prefrontal area were also traced. More specifically, the FLS was always recorded to terminate in Brodmann areas 6, 46, 45, and 10 (premotor cortex, dorsolateral prefrontal cortex, pars triangularis, and frontal pole, respectively), whereas terminations in Brodmann areas 4 (primary motor cortex), 47 (pars orbitalis), and 9 were also encountered in some specimens. In relation to the SLF system, the FLS represented its anterior continuation in the majority of the hemispheres, whereas in a few cases it was recorded as a completely distinct tract. Interestingly, the FLS comprised shorter fibers that were recorded to interconnect exclusively frontal areas, thus exhibiting different fiber architecture when compared to the long fibers forming the SLF.

CONCLUSIONS The current study provides consistent, focused, and robust evidence on the morphology, architecture, and correlative anatomy of the FLS. This fiber system participates in the axonal connectivity of the prefrontal-premotor cortices and allegedly subserves cognitive-motor functions. Based in the SLF hypersegmentation concept that has been advocated by previous authors, the FLS should be approached as a distinct frontal segment within the superior longitudinal system.

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Is Falcine Meningioma a Diffuse Disease of the Falx? Case Series and Analysis of a “Grade Zero” Resection

Neurosurgery, Volume 87, Issue 5, November 2020, Pages 900–909

Falcine meningiomas have unique characteristics including their high rates of recurrence, associationwith high grade pathology, increased male prevalence, and potential for diffuse involvement of the falx. OBJECTIVE: To address these issues in a substantial series of falcine meningiomas and report on the impact of extent of resection for this distinct meningioma entity.

METHODS: Retrospective analysis of characteristics and outcomes of 59 falcine meningioma patients who underwent surgery with the senior author. A “Grade Zero” category was used when an additional resection margin of 2 to 3 cm from the tumor insertion was achieved.

RESULTS: For de novo falcine meningiomas, gross total resection (GTR) was associated with significantly decreased recurrence incidence compared with subtotal resection (P ≤ .0001). For recurrent falcine meningiomas, median progression-free survival (PFS) was significantly improved for GTR cases (37 mo vs 12 mo; P = .017, hazard ratio (HR) .243 (.077-.774)). “Grade Zero” resection demonstrated excellent durability for both de novo and recurrent cases, and PFS was significantly improved with “Grade Zero” resection for recurrent cases (P = .003, HR 1.544 (1.156-2.062)). The PFS benefit of “Grade Zero” resection did not achieve statistical significance over Simpson grade 1 during the limited follow-up period (mean 2.8 yr) for these groups.

CONCLUSION: The recurrence of falcine meningiomas is related to the diffuse presence of tumor between the leaflets of the falx. Increased extent of resection including, when possible, a clear margin of falx surrounding the tumor base was associated with the best long-term outcomes in our series, particularly for recurrent tumors.

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Comparison of 5-aminolevulinic acid and sodium fluorescein for intraoperative tumor visualization in patients with high-grade gliomas

J Neurosurg 133:1324–1331, 2020

Maximal safe resection is an important surgical goal in the treatment for high-grade gliomas. Fluorescent dyes help the surgeon to distinguish malignant tissue from healthy. The aims of this study were 1) to compare the 2 fluorescent dyes 5-aminolevulinic acid (5-ALA) and sodium fluorescein (fluorescein) regarding extent of resection, progression- free survival, and overall survival; and 2) to assess the influence of other risk factors on clinical outcome and screen for potential disadvantages of the dyes.

METHODS A total of 209 patients with high-grade gliomas were included in this retrospective study. Resections were performed in the period from 2012 to 2017 using 5-ALA or fluorescein. Extent of resection was assessed as the difference in tumor volume between early postoperative and preoperative MRI studies. Tumor progression–free survival and overall survival were analyzed using an adjusted Cox proportional hazards model.

RESULTS One hundred fifty-eight patients were operated on with 5-ALA and 51 with fluorescein. The median duration of follow-up was 46.7 and 21.2 months, respectively. Covariables were evenly distributed. There was no statistically significant difference in volumetrically assessed median extent of resection (96.9% for 5-ALA vs 97.4% for fluorescein, p = 0.46) or the percentage of patients with residual tumor volume less than 0.175 cm3 (29.5% for 5-ALA vs 36.2% for fluorescein, p = 0.39). The median overall survival was 14.8 months for the 5-ALA group and 19.7 months for the fluorescein group (p = 0.06). The median adjusted progression-free survival was 8.7 months for the 5-ALA group and 9.2 months for the fluorescein group (p = 0.03).

CONCLUSIONS Fluorescein can be used as a viable alternative to 5-ALA for intraoperative fluorescent guidance in brain tumor surgery. Comparative, prospective, and randomized studies are much needed.

 

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Diagnostic Accuracy of Non-Invasive Thermal Evaluation of Ventriculoperitoneal Shunt Flow in Shunt Malfunction

Neurosurgery 87:939–948, 2020

Thermal flow evaluation (TFE) is a non-invasive method to assess ventriculoperitoneal shunt function. Flow detected by TFE is a negative predictor of the need for revision surgery. Further optimization of testing protocols, evaluation in multiple centers, and integration with clinical and imaging impressions prompted the current study.

OBJECTIVE: To compare the diagnostic accuracy of 2 TFE protocols, with micropumper (TFE+MP) or without (TFE-only), to neuro-imaging in patients emergently presenting with symptoms concerning for shunt malfunction.

METHODS: We performed a prospective multicenter operator-blinded trial of a consecutive series of patients who underwent evaluation for shunt malfunction. TFE was performed, and preimaging clinician impressions and imaging results were recorded. The primary outcome was shunt obstruction requiring neurosurgical revision within 7 d. Noninferiority of the sensitivity of TFE vs neuro-imaging for detecting shunt obstruction was tested using a prospectively determined a priori margin of −2.5%.

RESULTS: We enrolled 406 patients at 10 centers. Of these, 68/348 (20%) evaluated with TFE+MP and 30/215 (14%) with TFE-only had shunt obstruction. The sensitivity for detecting obstruction was 100% (95% CI: 88%-100%) for TFE-only, 90% (95% CI: 80%-96%) for TFE+MP, 76% (95% CI: 65%-86%) for imaging in TFE+MP cohort, and 77%(95% CI: 58%- 90%) for imaging in the TFE-only cohort. Difference in sensitivities between TFE methods and imaging did not exceed the non-inferiority margin.

CONCLUSION: TFE is non-inferior to imaging in ruling out shunt malfunction and may help avoid imaging and other steps. For this purpose, TFE only is favored over TFE+MP.

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Detailed analysis of 5-aminolevulinic acid induced fluorescence in different brain metastases at two specialized neurosurgical centers: experience in 157 cases

J Neurosurg 133:1032–1043, 2020

Incomplete neurosurgical resection of brain metastases (BM) due to insufficient intraoperative visualization of tumor tissue is a major clinical challenge and might result in local recurrence. Recently, visible 5-aminolevulinic acid (5-ALA) induced fluorescence was first reported in patients with BM. The aim of this study was thus to investigate, for the first time systematically, the value of 5-ALA fluorescence for intraoperative visualization of BM in a large patient cohort.

METHODS Adult patients (≥ 18 years) with resection of suspected BM after preoperative 5-ALA administration were prospectively recruited at two specialized neurosurgical centers. During surgery, the fluorescence status (visible or no fluorescence); fluorescence quality (strong, vague, or none); and fluorescence homogeneity (homogeneous or heterogeneous) of each BM was investigated. Additionally, these specific fluorescence characteristics of BM were correlated with the primary tumor type and the histopathological subtype. Tumor diagnosis was established according to the current WHO 2016 criteria.

RESULTS Altogether, 157 BM were surgically treated in 154 patients. Visible fluorescence was observed in 104 BM (66%), whereas fluorescence was absent in the remaining 53 cases (34%). In detail, 53 tumors (34%) showed strong fluorescence, 51 tumors (32%) showed vague fluorescence, and 53 tumors (34%) had no fluorescence. The majority of BM (84% of cases) demonstrated a heterogeneous fluorescence pattern. According to primary tumor, visible fluorescence was less frequent in BM of melanomas compared to all other tumors (p = 0.037). According to histopathological subtype, visible fluorescence was more common in BM of ductal breast cancer than all other subtypes (p = 0.008). It is of note that visible fluorescence was observed in the surrounding brain tissue after the resection of BM in 74 (67%) of 111 investigated cases as well.

CONCLUSIONS In this largest series to date, visible 5-ALA fluorescence was detected in two-thirds of BM. However, the characteristic heterogeneous fluorescence pattern and frequent lack of strong fluorescence limits the use of 5-ALA in BM and thus this technique needs further improvements.

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Minimally invasive surgical treatment of intracranial meningiomas in elderly patients (≥ 65 years): outcomes, readmissions, and tumor control

Neurosurg Focus 49 (4):E17, 2020

Increased lifespan has led to more elderly patients being diagnosed with meningiomas. In this study, the authors sought to analyze and compare patients ≥ 65 years old with those < 65 years old who underwent minimally invasive surgery for meningioma. To address surgical selection criteria, the authors also assessed a cohort of patients managed without surgery.

METHODS In a retrospective analysis, consecutive patients with meningiomas who underwent minimally invasive (endonasal, supraorbital, minipterional, transfalcine, or retromastoid) and conventional surgical treatment approaches during the period from 2008 to 2019 were dichotomized into those ≥ 65 and those < 65 years old to compare resection rates, endoscopy use, complications, and length of hospital stay (LOS). A comparator meningioma cohort of patients ≥ 65 years old who were observed without surgery during the period from 2015 to 2019 was also analyzed.

RESULTS Of 291 patients (median age 60 years, 71.5% females, mean follow-up 36 months) undergoing meningioma resection, 118 (40.5%) were aged ≥ 65 years and underwent 126 surgeries, including 20% redo operations, as follows: age 65–69 years, 46 operations; 70–74 years, 40 operations; 75–79 years, 17 operations; and ≥ 80 years, 23 operations. During 2015–2019, of 98 patients referred for meningioma, 67 (68%) had surgery, 1 (1%) had radiosurgery, and 31 (32%) were observed. In the 11-year surgical cohort, comparing 173 patients < 65 years versus 118 patients ≥ 65 years old, there were no significant differences in tumor location, size, or outcomes. Of 126 cases of surgery in 118 elderly patients, the approach was a minimally invasive approach to skull base meningioma (SBM) in 64 cases (51%) as follows: endonasal 18, supraorbital 28, minipterional 6, and retrosigmoid 12. Endoscope-assisted surgery was performed in 59.5% of patients. A conventional approach to SBM was performed in 15 cases (12%) (endoscope-assisted 13.3%), and convexity craniotomy for non–skull base meningioma (NSBM) in 47 cases (37%) (endoscope-assisted 17%). In these three cohorts (minimally invasive SBM, conventional SBM, and NSBM), the gross-total/near-total resection rates were 59.5%, 60%, and 91.5%, respectively, and an improved or stable Karnofsky Performance Status score occurred in 88.6%, 86.7%, and 87.2% of cases, respectively. For these 118 elderly patients, the median LOS was 3 days, and major complications occurred in 10 patients (8%) as follows: stroke 4%, vision decline 3%, systemic complications 0.7%, and wound infection or death 0. Eighty-three percent of patients were discharged home, and readmissions occurred in 5 patients (4%). Meningioma recurrence occurred in 4 patients (3%) and progression in 11 (9%). Multivariate regression analysis showed no significance of American Society of Anesthesiologists physical status score, comorbidities, or age subgroups on outcomes; patients aged ≥ 80 years showed a trend of longer hospitalization.

CONCLUSIONS This analysis suggests that elderly patients with meningiomas, when carefully selected, generally have excellent surgical outcomes and tumor control. When applied appropriately, use of minimally invasive approaches and endoscopy may be helpful in achieving maximal safe resection, reducing complications, and promoting short hospitalizations. Notably, one-third of our elderly meningioma patients referred for possible surgery from 2015 to 2019 were managed nonoperatively.

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In vitro performance of six combinations of adjustable differential pressure valves and fixed anti-siphon devices with and without vertical motion

Acta Neurochirurgica (2020) 162:2421–2430

Adjustable differential pressure (DP) valves in combination with fixed anti-siphon devices are currently a popular combination in counteracting the effects of cerebrospinal fluid overdrainage following implantation of a ventriculoperitoneal shunt system. The study examined the flowperformance of three DP valves in successive combination with an anti-siphon device in an in vitro shunt laboratory with and without vertical motion.

Methods We analyzed three DP valves (Codman Hakim Medos programmable valve [HM], Codman CertasPlus [CP], and Miethke proGAV [PG], in combination with either Codman SiphonGuard [SG] or Miethke ShuntAssistant [SA]), resulting in the evaluation of six different valve combinations. Defined DP conditions between 4 and 40 cmH2O within a simulated shunt system were generated and the specific flow characteristics were measured. In addition, combinations with SA, which is a gravitydependent valve, were measured in defined spatial positions (90°, 60°). All device combinations were tested during vertical motion with movement frequencies of 2, 3, and 4 Hz.

Results All valve combinations effectively counteracted the siphon effect in relation to the chosen DP. Angulation-related flow changes were similar in the three combinations of DP valve and SA in the 60° and 90° position. In CP-SA and PG-SA, repeated vertical movement at 2, 3, and 4 Hz led to significant increase in flow, whereas in HM-SA, constant increase was seen at 4 Hz only (flow change at 4Hz, DP 40 cm H2O: PG (opening pressure 4 cm H2O) 90°: 0.95 ml/min, 60°: 0.71 ml/min; HM (opening pressure 4 cmH2O) 90°: 0.66 ml/min, 60°: 0.41ml/min; CP (PL 2) 90°: 0.94ml/min, 60°: 0.79 ml/min; p < 0.01); however, HMSA showed relevant motion-induced flow already at low DPs (0.85 ml/min, DP 4 cm H2O). In combinations of DP valve with SG, increase of flow was far less pronounced and even led to significant reduction of flow in certain constellations. Maximum overall flow increase was 0.46 ± 0.04ml/min with aHM(opening pressure 12 cm H2O) at 2 Hz and a DP of 10 cmH2O, whereas maximum flow decrease was 1.12 ± 0.08 with a PG (opening pressure 4 cm H2O) at 3 Hz and a DP of 10 cmH2O.

Conclusion In an experimental setup, all valve combinations effectively counteracted the siphon effect in the vertical position according to their added resistance. Motion-induced increased flow was consistently demonstrated in combinations of DP valve and SA. The combination of HM and SA especially showed relevant motion-induced flow already at low DPs. In combinations of DP and SG, the pattern of the motion induced flow was more inconsistent and motion even led to significant flow reduction, predominantly at DPs of 10 and 20 cmH2O.

 

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Stereotactic CT image guidance and biplanar fluoroscopy for transoral C2 vertebroplasty and direct anterolateral subaxial vertebroplasty

Acta Neurochirurgica (2020) 162:2533–2536

Metastatic cervical spine disease can cause compression fractures, cervical spine instability, and pain. Vertebroplasty can stabilize a fracture, reduce the pain associated with a compression fracture, prevent or stop the progression of a fracture, thus avoiding cervical spine fixation, and decreased mobility. Transoral C2 vertebroplasty is less invasive than open fusion surgery, but it poses its own risk of infection and cement leak in this highly sensitive area.

Methods The image guidance setup consisted of the Stryker NAV3i navigation system, Stryker CranialMask tracker, and the CranialMap 3.0 software combined with biplanar fluoroscopy.

Results The patient’s neck pain has completely resolved immediately after the surgery. There were no complications.

Conclusion Quality of life preservation is paramount in the management of metastatic spine disease. Vertebroplasty of osteolytic lesions can both relieve pain and restore stability, thus avoiding permanent stiff cervical collar, halo vest, or upfront occipitocervical fusion. With the increasing availability of surgical navigation systems, its use combined with biplanar fluoroscopy for performing transoral C2 vertebroplasty seems to be an adequate treatment in selected cases for pain relief, stabilization, and maintaining quality of life in the complex cancer population with C2 pathological fractures. The article describes as well vertebroplasty of the subaxial spine through a conventional anterior approach which again seems to be adequate in the treatment of spinal pathological fractures.

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