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Sphenoparietal sinus transposition technique: optimization of the surgical corridor with preservation of prominent bridging veins between the brain and the cranial base during aneurysm clipping via the pterional approach

J Neurosurg 134:999–1005, 2021

The sylvian bridging veins between the brain and the dura on the inner surface of the sphenoid wing can restrict brain retraction for widening of the lateral retrocarotid space during clipping surgery for internal carotid artery (ICA)–posterior communicating artery (PCoA) and basilar apex (BX) aneurysms. In such cases, the authors perform extradural anterior clinoidectomy with peeling of the temporal dura propria from the periosteal dura and inner cavernous membrane around the superior orbital fissure, with the incision of the dura mater stretching from the base of the temporal side to just before the distal dural ring of the ICA (termed by the authors as the sphenoparietal sinus transposition [SPST] technique). This technique displaces the bridging segment of the sylvian vein posteriorly and enables widening of the surgical space without venous injury. In this study, the authors observed the operative nuances and investigated the usefulness of this technique.

METHODS The authors retrospectively reviewed the medical charts of 66 consecutive patients with ICA-PCoA and BX aneurysms between January 2016 and July 2018. This technique was performed in 8 patients (5 patients with PCoA aneurysms and 3 with BX aneurysms) in whom the bridging segments of the sylvian veins between the brain and the skull base restricted brain retraction for widening of the surgical space. The surface areas of the lateral retrocarotid space and the aneurysm were measured at the most visible working angle before and after the SPST technique was performed.

RESULTS With the use of the SPST technique, an adequate surgical space for aneurysm clipping was obtained with preservation of the bridging veins in all patients. The mean surface areas of the lateral retrocarotid space (p = 0.002) and aneurysm (p = 0.001) were significantly increased from 18.3 ± 18.8 and 2.8 ± 2.5 cm2 before to 64.2 ± 21.1 and 20.9 ± 20.6 cm2, respectively, after the SPST technique was performed.

CONCLUSIONS The SPST technique enables displacement of the bridging segments of the sylvian veins without venous injury and enables widening of the surgical space around the lateral retrocarotid area.

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Clinical Pearls and Methods for Intraoperative Motor Mapping

Neurosurgery 88:457–467, 2021

Resection of brain tumors involving motor areas and pathways requires the identification and preservation of various cortical and subcortical structures involved in motor control at the time of the procedure, in order to maintain the patient’s full motor capacities. The use of brain mapping techniques has now been integrated into clinical practice for many years, as they help the surgeon to identify the neural structures involved in motor functions. A common definition of motor function, as well as knowledge of its neural organization, has been continuously evolving, underlining the need for implementing intraoperative strategies at the time of the procedure. Similarly, mapping strategies have been subjected to continuous changes, enhancing the likelihood of preservation of full motor capacities. As a general rule, the motor mapping strategy should be as flexible as possible and adapted strictly to the individual patient and clinical context of the tumor.

In this work, we present an overview of current knowledge of motor organization, indications for motor mapping, available motor mapping, and monitoring strategies, as well as their advantages and limitations. The use of motor mapping improves resection and outcomes in patients harboring tumors involving motor areas and pathways, and should be considered the gold standard in the resection of this type of tumor.

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Hyperostosing sphenoid wing meningiomas: surgical outcomes and strategy for bone resection and multidisciplinary orbital reconstruction

J Neurosurg 134:711–720, 2021

Hyperostosing sphenoid wing meningiomas cause bony hyperostosis that may extend into the orbit, resulting in proptosis, restriction of extraocular movements, and/or compressive optic neuropathy. The extent of bony removal necessary and the optimal reconstruction strategy to prevent enophthalmos is debated. Herein, the authors present their surgical outcomes and reconstruction results.

METHODS This is a retrospective review of 54 consecutive patients undergoing resection of sphenoid wing meningiomas associated with bony hyperostosis. The majority of cases were operated on by the senior author. Extent of tumor resection, volumetric bone resection, radiographic exophthalmos index, complications, and recurrence were analyzed.

RESULTS The median age of the cohort was 52.1 years, with women comprising 83% of patients. Proptosis was a presenting symptom in 74%, and 52% had decreased visual acuity. The WHO grade was I (85%) or II (15%). The median follow-up was 2.6 years. On volumetric analysis, a median 86% of hyperostotic bone was resected. Gross-total resection of the intracranial tumor was achieved in 43% and the orbital tumor in 27%, and of all intracranial and orbital components in 20%. Orbital reconstruction was performed in 96% of patients. Postoperative vision was stable or improved in 98% of patients and diplopia improved in 89%. Postoperative complications occurred in 44% of patients, and 26% of patients underwent additional surgery for complication management. The most frequent complications were medical complications and extraocular movement deficits. The median preoperative exophthalmos index was 1.26, which improved to 1.12 immediately postoperatively and to 1.09 at the 6-month follow-up (p < 0.001). Postoperatively, 18 patients (33%) underwent adjuvant radiotherapy after subtotal resection. Tumors recurred/progressed in 12 patients (22%).

CONCLUSIONS Resection of hyperostosing sphenoid wing meningiomas, particularly achieving gross-total resection of hyperostotic bone with a good aesthetic result, is challenging and associated with notable medical and ocular morbidity. Recurrence rates in this series are higher than previously reported. Nevertheless, the authors were able to attain improvement in proptosis and visual symptoms in the majority of patients by using a multidisciplinary approach.

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Cerebrospinal fluid area and syringogenesis in Chiari malformation type I

J Neurosurg 134:825–830, 2021

Syringogenesis in Chiari malformation type I (CM-I) is thought to occur secondary to impaction of the cerebellar tonsils within the foramen magnum (FM). However, the correlation between the CSF area and syringogenesis has yet to be elucidated. The authors sought to determine whether the diminution in subarachnoid space is associated with syringogenesis. Further, the authors sought to determine if syrinx resolution was associated with the degree of expansion of subarachnoid spaces after surgery.

METHODS The authors performed a retrospective review of all patients undergoing posterior fossa decompression for CM-I from 2004 to 2016 at the University of Virginia Health System. The subarachnoid spaces at the FM and at the level of the most severe stenosis were measured before and after surgery by manual delineation of the canal and neural tissue area on MRI and verified through automated CSF intensity measurements. Imaging and clinical outcomes were then compared.

RESULTS Of 68 patients, 26 had a syrinx at presentation. Syrinx patients had significantly less subarachnoid space at the FM (13% vs 19%, p = 0.0070) compared to those without syrinx. Following matching based on degree of tonsillar herniation and age, the subarachnoid space was significantly smaller in patients with a syrinx (12% vs 19%, p = 0.0015). Syrinx resolution was associated with an increase in patients’ subarachnoid space after surgery compared with those patients without resolution (23% vs 10%, p = 0.0323).

CONCLUSIONS Syrinx development in CM-I patients is correlated with the degree to which the subarachnoid CSF spaces are diminished at the cranial outlet. Successful syrinx reduction is associated with the degree to which the subarachnoid spaces are increased following surgery.

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Natural history of brainstem cavernous malformations

J Neurosurg 134:917–928, 2021

Given the paucity of data on the natural history of brainstem cavernous malformations (CMs), the authors aimed to evaluate the annual hemorrhage rate and hemorrhagic risk of brainstem CMs.

METHODS Nine hundred seventy-nine patients diagnosed with brainstem CMs were referred to Beijing Tiantan Hospital from 2006 to 2015; 224 patients were excluded according to exclusion criteria, and 47 patients were lost to follow-up. Thus, this prospective observational cohort included 708 cases (324 females). All patients were registered, clinical data were recorded, and follow-up was completed.

RESULTS Six hundred ninety (97.5%) of the 708 patients had a prior hemorrhage, 514 (72.6%) had hemorrhagic presentation, and developmental venous anomaly (DVA) was observed in 241 cases (34.0%). Two hundred thirty-seven prospective hemorrhages occurred in 175 patients (24.7%) during 3400.2 total patient-years, yielding a prospective annual hemorrhage rate of 7.0% (95% CI 6.2%–7.9%), which decreased to 4.7% after the 1st year. Multivariate Cox regression analysis after adjusting for sex and age identified hemorrhagic presentation (HR 1.574, p = 0.022), DVA (HR 1.678, p = 0.001), mRS score ≥ 2 on admission (HR 1.379, p = 0.044), lesion size > 1.5 cm (HR 1.458, p = 0.026), crossing the axial midpoint (HR 1.446, p = 0.029), and superficially seated location (HR 1.307, p = 0.025) as independent adverse factors for prospective hemorrhage, but history of prior hemorrhage was not significant. The annual hemorrhage rates were 8.3% and 4.3% in patients with and without hemorrhagic presentation, respectively; the rate was 9.9%, 6.0%, and 1.0% in patients with ≥ 2, only 1, and 0 prior hemorrhages, respectively; and the rate was 9.2% in patients with both hemorrhagic presentation and focal neurological deficit on admission.

CONCLUSIONS The study reported an annual hemorrhage rate of 7.0% exclusively for brainstem CMs, which significantly increased if patients presented with both hemorrhagic presentation and focal neurological deficit (9.2%), or any other risk factor. Patients with a risk factor for hemorrhage needed close follow-up regardless of the number of prior hemorrhages. It should be noted that the referral bias in this study could have overestimated the annual hemorrhage rate. This study improved the understanding of the natural history of brainstem CMs, and the results are important for helping patients and physicians choose a suitable treatment option based on the risk factors and stratified annual rates. Clinical trial registration no.: ChiCTR-POC-17011575 (http://www.chictr.org.cn/).

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Spinal laser interstitial thermal therapy: single-center experience and outcomes in the first 120 cases

J Neurosurg Spine 34:354–363, 2021

The objective of this study was to present the results of a consecutive series of 120 cases treated with spinal laser interstitial thermal therapy (sLITT) to manage epidural spinal cord compression (ESCC) from metastatic tumors.

METHODS The electronic records of patients treated from 2013 to 2019 were analyzed retrospectively. Data collected included demographic, pathology, clinical, operative, and imaging findings; degree of epidural compression before and after sLITT; length of hospital stay; complications; and duration before subsequent oncological treatment. Independent-sample t-tests were used to compare means between pre- and post-sLITT treatments. Survival was estimated by the Kaplan-Meier method. Multivariate logistic regression was used to analyze predictive factors for local recurrence and neurological complications.

RESULTS There were 110 patients who underwent 120 sLITT procedures. Spinal levels treated included 5 cervical, 8 lumbar, and 107 thoracic. The pre-sLITT Frankel grades were E (91.7%), D (6.7%), and C (1.7%). The preoperative ESCC grade was 1c or higher in 92% of cases. Metastases were most common from renal cell carcinoma (39%), followed by non–small cell lung carcinoma (10.8%) and other tumors (35%). The most common location of ESCC was in the vertebral body (88.3%), followed by paraspinal/foraminal (7.5%) and posterior elements (4.2%). Adjuvant radiotherapy (spinal stereotactic radiosurgery or conventional external beam radiation therapy) was performed in 87 cases (72.5%), whereas 33 procedures (27.5%) were performed as salvage after radiotherapy options were exhausted. sLITT was performed without need for spinal stabilization in 87 cases (72.5%). Post-sLITT Frankel grades were E (85%), D (10%), C (4.2%), and B (0.8%); treatment was associated with a median decrease of 2 ESCC grades. The local control rate at 1 year was 81.7%. Local control failure occurred in 25 cases (20.8%). The median progression-free survival was not reached, and overall survival was 14 months. Tumor location in the paraspinal region and salvage treatment were independent predictors of local recurrence, with hazard ratios of 6.3 and 3.3, respectively (p = 0.01). Complications were observed in 22 cases (18.3%). sLITT procedures performed in the lumbar and cervical spine had hazard ratios for neurological complications of 15.4 and 17.1 (p < 0.01), respectively, relative to the thoracic spine.

CONCLUSIONS sLITT is safe and provides effective local control for high-grade ESCC from vertebral metastases in the thoracic spine, particularly when combined with adjuvant radiotherapy. The authors propose considering sLITT as an alternative to open surgery in selected patients with spinal metastases.

 

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How I do it: retrosigmoid intradural inframeatal petrosectomy

Acta Neurochirurgica (2021) 163:649–653

Lesions infiltrating the petrous temporal bone are some of the most complex to treat surgically. Many approaches have been developed in order to address these lesions, including endoscopic endonasal, anterior petrosectomy, posterior petrosectomy, and retrosigmoid.

Method We describe in a stepwise fashion the surgical steps of the retrosigmoid intradural inframeatal petrosectomy.

Conclusion The retrosigmoid intradural inframeatal petrosectomy may afford satisfactory exposure with limited drilling and minimal disruption of perilesional anatomical structures. It can provide excellent surgical results, especially for soft tumors, while minimizing surgical morbidity.

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Low-Dose Intravenous Heparin Infusion After Aneurysmal Subarachnoid Hemorrhage is Associated With Decreased Risk of Delayed Neurological Deficit and Cerebral Infarction

Neurosurgery 88 (3)2021: 523–530

Patients who survive aneurysmal subarachnoid hemorrhage (aSAH) are at risk for delayed neurological deficits (DND) and cerebral infarction. In this exploratory cohort comparison analysis, we compared in-hospital outcomes of aSAH patients administered a low-dose intravenous heparin (LDIVH) infusion (12 U/kg/h) vs those administered standard subcutaneous heparin (SQH) prophylaxis for deep vein thrombosis (DVT; 5000 U, 3 × daily).

OBJECTIVE: To assess the safety and efficacy of LDIVH in aSAH patients.

METHODS: We retrospectively analyzed 556 consecutive cases of aSAH patients whose aneurysm was secured by clipping or coiling at a single institution over a 10-yr period, including 233 administered the LDIVH protocol and 323 administered the SQH protocol. Radiological and outcome datawere compared between the 2 cohorts using multivariable logistic regression and propensity score-based inverse probability of treatment weighting (IPTW).

RESULTS: The unadjusted rate of cerebral infarction in the LDIVH cohort was half that in SQH cohort (9 vs 18%; P = .004). Multivariable logistic regression showed that patients in the LDIVH cohort were significantly less likely than those in the SQH cohort to have DND (odds ratio (OR) 0.53 [95% CI: 0.33, 0.85]) or cerebral infarction (OR 0.40 [95% CI: 0.23, 0.71]). Analysis following IPTWshowed similar results. Rates of hemorrhagic complications, heparin-induced thrombocytopenia and DVT were not different between cohorts.

CONCLUSION: This cohort comparison analysis suggests that LDIVH infusion may favorably influence the outcome of patients after aSAH. Prospective studies are required to further assess the benefit of LDIVH infusion in patients with aSAH.

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Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Neuroablative Procedures for Patients With Cancer Pain

Neurosurgery 88:437–442, 2021

Managing cancer pain once it is refractory to conventional treatment continues to challenge caregivers committed to serving those who are suffering from a malignancy. Although neuromodulation has a role in the treatment of cancer pain for some patients, these therapies may not be suitable for all patients. Therefore, neuroablative procedures,whichwere once a mainstay in treating intractable cancer pain, are again on the rise. This guideline serves as a systematic review of the literature of the outcomes following neuroablative procedures.

OBJECTIVE: To establish clinical practice guidelines for the use of neuroablative procedures to treat patients with cancer pain.

METHODS: A systematic review of neuroablative procedures used to treat patients with cancer pain from 1980 to April 2019 was performed using the United States National Library of Medicine PubMed database, EMBASE, and Cochrane CENTRAL. After inclusion criteria were established, full text articles that met the inclusion criteria were reviewed by 2 members of the task force and the quality of the evidence was graded.

RESULTS: In total, 14 646 relevant abstracts were identified by the literature search, from which 189 met initial screening criteria. After full text review, 58 of the 189 articles were included and subdivided into 4 different clinical scenarios. These include unilateral somatic nociceptive/neuropathic body cancer pain, craniofacial cancer pain,midline subdiaphragmatic visceral cancer pain, and disseminated cancer pain. Class II and III evidence was available for these 4 clinical scenarios. Level III recommendations were developed for the use of neuroablative procedures to treat patients with cancer pain.

CONCLUSION: Neuroablative procedures may be an option for treating patients with refractory cancer pain. Serious adverse events were reported in some studies, but were relatively uncommon. Improved imaging, refinements in technique and the availability of new lesioning modalities may minimize the risks of neuroablation even further. The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelinesdetail/ guidelines-on-neuroablative-procedures-patients-wi.

 

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Vitamin D—A New Perspective in Treatment of Cerebral Vasospasm

Neurosurgery 88 (3) 2021: 674–685

Cerebral vasospasm (CVS) is a frequent complication after subarachnoid hemorrhage (SAH), with no sufficient therapy and a complex pathophysiology.

OBJECTIVE: To explore the vitamin D system as a potential treatment for CVS.

METHODS: 25-vitamin D3 levels tested between 2007 and 2015 and data of SAH patients admitted during themonthswith a peak vs nadir of VitD3 valueswere analyzed, retrospectively. We prospectively correlated VitD3 and vasospasm/outcome data in SAH patients admitted in 2017. An experimental mice SAH model and cell culture model were used to investigate the effect of 1,25-dihydroxyvitamin D3 (1,25-VitD3). Additionally, the mediators acting in the VitD mechanism were researched and detected.

RESULTS: Based on the retrospective analysis demonstrating an increased frequency of vasospasm in SAH patients during the low vitamin D period in winter, we started basic research experiments. Active 1,25-VitD3 hormone attenuated CVS, neurological deficit, and inflammation after intrathecal blood injection inmice. Deletion of the vitaminDreceptor in the endothelium or in myeloid cells decreased the protective 1,25-VitD3 effect. Co-culture experiments ofmyeloid and endothelial cells with blood confirmed the anti-inflammatory 1,25-VitD3 effect but also revealed an induction of stroma-cell-derived factor 1α (SDF1α), vascular endothelial growth factor, and endothelial nitric oxide synthase by 1,25-VitD3. In mice, SDF1α mimicked the protective effect of 1,25-VitD3 against CVS. From bench to bedside, CVS severity was inversely correlated with vitamin D plasma level, prospectively. Patients with more severe CVS exhibited attenuated expression of SDF1α and 1,25-VitD3- responsive genes on circulating myeloid cells.

CONCLUSION: 1,25-VitD3 attenuates CVS after SAH by inducing SDF1α. However, VitD administration should be tested as optional treatment to prevent CVS.

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Occult infection in pseudarthrosis revision after spinal fusion

The Spine Journal 21 (2021) 370−376

Pseudarthrosis after attempted spinal fusion is yet not sufficiently understood and presents a surgical challenge. Occult infections are sometimes observed in patients with pseudarthrosis and no inflammatory signs of infection. The prevalence of such occult infection and its association with patient demographics and inflammatory markers are largely unknown.

PURPOSE: To determine the prevalence of unexpected low-grade infection in spinal pseudarthrosis revision surgery, and to evaluate whether such infection is associated with patient demographics and inflammatory markers.

STUDY DESIGN: Retrospective observational study.

PATIENT SAMPLE: One-hundred-and-twenty-eight patients who underwent thoracolumbar revision surgery due to presumed aseptic pseudarthrosis after spinal instrumentation.

OUTCOME MEASURES: Culture-positive infections or noninfectious pseudarthrosis. METHODS: Samples were routinely taken for microbiological examination from all adults (n=152) who underwent revision surgery for presumed aseptic thoracolumbar pseudarthrosis between 2014 and 2019. A full intraoperative microbiological workup (at least three intraoperative tissue samples) was done for 128 (84%) patients, and these patients were included in further analyses. Patient characteristics, medical history, inflammatory markers, and perioperative data were compared between those with and without microbiologically-confirmed infection based on samples obtained during pseudarthrosis revision.

RESULTS: The microbiological workup confirmed infection in 13 of 128 cases (10.2%). The predominant pathogen was Cutibacterium acnes (46.2%), followed by coagulase-negative staphylococci (38.5%). The presence of infection was associated with the body mass index (30.9§4.7 kg/m2 [infected] vs. 28.2§5.6 kg/m2 [controls], p=.049), surgery in the thoracolumbar region (46% vs. 18%, p=.019), and a slightly higher serum C-reactive protein level on admission (9.4§8.0 mg/L vs. 5.7§7.1 mg/L, p=.031). Occult infection was not associated with age, sex, prior lumbar surgeries, number of fused lumbar levels, American Society of Anesthesiologist score, Charlson Comorbidity Index, presence of diabetes mellitus, and smoking status.

CONCLUSIONS: Occult infections were found in 10% of patients undergoing pseudarthrosis revision after spinal fusion, even without preoperative clinical suspicion. Occult infection was associated with higher body mass index, fusions including the thoracolumbar junction, and slightly higher C-reactive protein levels. Intraoperative microbiological samples should be routinely obtained to exclude or identify occult infection in all revision surgeries for symptomatic pseudarthrosis of the spine, as this information can be used to guide postoperative antibiotic treatment.

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Trigeminal schwannoma: a single-center experience with 43 cases and review of literature

British Journal of Neurosurgery 2021, 35:1, 49-56

Trigeminal schwannomas (TS) are rare, when compared to vestibular schwannomas. The present study aims to analyze the clinical characteristics and surgical strategies of TS via the retrospective analysis of the clinical data of 43 patients.

Methods: The clinical information of 43 patients diagnosed with TS, who were surgically treated from January 2008 to January 2018, was retrospectively analyzed. Then, the selection of approaches and surgical strategies were discussed.

Results: During the last 10 years, 43 patients with TS received surgical treatment at Xuan Wu Hospital of Capital Medical University. Facial numbness and hypoesthesia were the most common symptoms, which developed in 29 cases (67.4%). Typical trigeminal neuralgia was complained by four patients (9.3%), while trigeminal motor impairment developed in nine cases (20.9%). The tumor was totally removed in 39 patients (90.7%), near-totally removed in three patients (7.0%), and partially removed in one patient (2.3%) due to intraoperative internal carotid artery (ICA) injury. The abducens was intraoperatively damaged in two patients (4.7%). After the operation, all four patients with trigeminal neuralgia achieved total recovery, but the facial numbness still continued in 24 patients (82.8%). At a median of 45.3 ± 25.5 (6–84) months of follow up, a tumor recurred in only one patient, and this patient received a second operation.

Conclusion: It can be concluded that total removal via the proper approach can be the best treatment for TS with a low complication rate. However, preoperative symptoms, such as facial numbness and trigeminal motor impairment that seldom improved though normal fibers, were carefully recognized and preserved during the operation.

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“Zooming in” on Glioblastoma: Understanding Tumor Heterogeneity and its Clinical Implications in the Era of Single-Cell Ribonucleic Acid Sequencing

Neurosurgery 88:477–486, 2021

Glioblastoma (GBM) is the most common primary brain malignancy in adults and one of the most aggressive of all human cancers. It is highly recurrent and treatment-resistant, in large part due to its infiltrative nature and inter- and intratumoral heterogeneity. This heterogeneity entails varying genomic landscapes and cell types within and between tumors and the tumor microenvironment (TME). In GBM, heterogeneity is a driver of treatment resistance, recurrence, and poor prognosis, representing a substantial impediment to personalized medicine.

Over the last decade, sequencing technologies have facilitated deeper understanding of GBM heterogeneity by “zooming in” progressively further on tumor genomics and transcriptomics. Initial efforts employed bulk ribonucleic acid (RNA) sequencing, which examines composite gene expression of whole tumor specimens. While groundbreaking at the time, this bulk RNAseq masks the crucial contributions of distinct tumor subpopulations to overall gene expression. This work progressed to the use of bulk RNA sequencing in anatomically and spatially distinct tumor subsections, which demonstrated previously underappreciated genomic complexity of GBM.

A revolutionary next step forward has been the advent of single-cell RNA sequencing (scRNAseq), which examines gene expression at the single-cell level. scRNAseq has enabled us to understand GBM heterogeneity in unprecedented detail.

We review seminal studies in our progression of understanding GBM heterogeneity, with a focus on scRNAseq and the insights that it has provided into understanding the GBM tumor mass, peritumoral space, and TME. We highlight preclinical and clinical implications of this work and consider its potential to impact neuro-oncology and to improve patient outcomes via personalized medicine.

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How I do it: anterior interhemispheric approach to tuberculum sellae meningiomas

Acta Neurochirurgica (2021) 163:643–648

Tuberculum sellae meningiomas are deep-seated tumors difficult to access, located in close relation with important neurovascular structures. While the transsphenoidal approach is linked to specific complications, the different reported transcranial approaches are associated with advantages and drawbacks due to the respective angle of attack, with some areas adequately exposed and others partially hidden.

Method We report the technical aspects of the anterior interhemispheric approach we practice.

Conclusion This approach has the advantage of providing full control over all the vasculo-nervous structures involved and of allowing access to the medial aspect of both optic canals tangentially to the dorsum sellae.

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Ten-Year Outcomes of 1- and 2-Level Cervical Disc Arthroplasty From the Mobi-C Investigational Device Exemption Clinical Trial

Neurosurgery 88:497–505, 2021

Short- and mid-term studies have shown the effectiveness of cervical disc arthroplasty (CDA) to treat cervical disc degeneration.

OBJECTIVE: To report the 10-yr outcomes of a multicenter experience with cervical arthroplasty for 1- and 2-level pathology.

METHODS: This was a prospective study of patients treated with CDA at 1 or 2 contiguous levels using the Mobi-C ®  Cervical Disc (Zimmer Biomet).  Following completion of the 7-yr Food and Drug Administration postapproval study, follow-up continued to 10 yr for consenting patients at 9 high-enrolling centers. Clinical and radiographic endpoints were collected out to 10 yr.

RESULTS: At 10 yr, patients continued to have significant improvement over baseline Neck Disability Index (NDI), neck and arm pain, neurologic function, and segmental range of motion (ROM). NDI and pain outcomes at 10 yr were significantly improved from 7 yr. Segmental and global ROM and sagittal alignment also were maintained from 7 to 10 yr. Clinically relevant adjacent segment pathology was not significantly different between 7 and 10 yr. The incidence of motion restricting heterotopic ossification at 10 yr was not significantly different from 7 yr for 1-level (30.7% vs 29.6%) or 2-level (41.7% vs 39.2%) patients. Only 2 subsequent surgeries were reported after 7 yr.

CONCLUSION: Our results through 10 yr were comparable to 7-yr outcomes, demonstrating that CDA with Mobi-C ® continues to be a safe and effective surgical treatment for patients with 1- or 2-level cervical degenerative disc disease.

 

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Preoperative embolization versus no embolization for WHO grade I intracranial meningioma

J Neurosurg 134:693–700, 2021

The controversy continues over the clinical utility of preoperative embolization for reducing tumor vascularity of intracranial meningiomas prior to resection. Previous studies comparing embolization and nonembolization patients have not controlled for detailed tumor parameters before assessing outcomes.

METHODS The authors reviewed the cases of all patients who underwent resection of a WHO grade I intracranial meningioma at their institution from 2008 to 2016. Propensity score matching was used to generate embolization and nonembolization cohorts of 52 patients each, and a retrospective review of clinical and radiological outcomes was performed.

RESULTS In total, 52 consecutive patients who underwent embolization (mean follow-up 34.8 ± 31.5 months) were compared to 52 patients who did not undergo embolization (mean follow-up 32.8 ± 28.7 months; p = 0.63). Variables controlled for included patient age (p = 0.82), tumor laterality (p > 0.99), tumor location (p > 0.99), tumor diameter (p = 0.07), tumor invasion into a major dural sinus (p > 0.99), and tumor encasement around the internal carotid artery or middle cerebral artery (p > 0.99). The embolization and nonembolization cohorts did not differ in terms of estimated blood loss during surgery (660.4 ± 637.1 ml vs 509.2 ± 422.0 ml; p = 0.17), Simpson grade IV resection (32.7% vs 25.0%; p = 0.39), perioperative procedural complications (26.9% vs 19.2%; p = 0.35), development of permanent new neurological deficits (5.8% vs 7.7%; p = 0.70), or favorable modified Rankin Scale (mRS) score (a score of 0–2) at last follow-up (96.0% vs 92.3%; p = 0.43), respectively. When comparing the final mRS score to the preoperative mRS score, patients in the embolization group were more likely than patients in the nonembolization group to have an improvement in mRS score (50.0% vs 28.8%; p = 0.03).

CONCLUSIONS After controlling for patient age, tumor size, tumor laterality, tumor location, tumor invasion into a major dural sinus, and tumor encasement of the internal carotid artery or middle cerebral artery, preoperative meningioma embolization intended to decrease tumor vascularity did not improve the surgical outcomes of patients with WHO grade I intracranial meningiomas, but it did lead to a greater chance of clinical improvement compared to patients not treated with embolization.

 

 

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The endoscopic supraorbital translaminar approach

Acta Neurochirurgica (2021) 163:635–641

Resection of lesions located within the third ventricle presents a surgical challenge. Several approaches have been developed in an attempt to obtain maximal resection, while minimizing brain retraction. In this work, we assess the surgical exposure and maneuverability of the endoscopic supraorbital translaminar approach (ESTA), a potential alternative to fenestrate the lamina terminalis and approach the third ventricle by using the endoscope through a keyhole supraorbital-eyebrow craniotomy.

Methods Five cadaveric heads were used to assess the corridor depth, area of exposure, and viewing angles offered by the ESTA. One additional utilized specimen provided a stepwise dissection of the approach.

Results The ESTA was successfully performed in all specimens. Depth of the surgical corridor from the craniotomy to the ipsilateral internal carotid artery (ICA), lamina terminalis, and contralateral carotid were 70.7 ± 2.9 mm, 73.2 ± 2.9 mm, and 78.9 ± 4.1 mm, respectively. Viewing angle referenced to the ipsilateral ICA was 6.5 ± 4.2°, while the viewing angle for the lamina terminalis was 25.8 ± 4.3°. The surgical exposure provided by the ESTA was 1655 ± 255 mm2.

Conclusions The ESTA provides a wide surgical view of the lamina terminalis and may be potentially used to approach lesions located in the anterior third of the third ventricle. As a pure endoscopic approach, the ESTA requires minimal brain retraction, while affords good visualization of targeted lesions around the lamina terminalis. The ESTA uses an anterolateral approach and so provides a short and straightforward approach to these structures.

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Prognostic nomogram for microvascular decompression–treated trigeminal neuralgia

Neurosurgical Review (2021) 44:571–577

This study aimed to establish an effective prognostic nomogram for microvascular decompression (MVD)–treated trigeminal neuralgia (TN). The nomogram was based on a retrospective cohort study of 1054 patients with TN.

During the period 2005– 2014, 845 patients at our department treated TN with MVD and served as a development cohort. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve. The model was externally validated by 209 TN patients during 2014–2016.

Multivariate cox analysis suggested that the patient’s age, atypical pain, vascular type, number of offending vessels, and second MVD were significant factors influencing the prognosis of MVDtreated TN. The C index of nomogram in the development cohort was 0.767 (95%CI, 0.739–0.794), and 0.749 (95%CI, 0.688– 0.810) in the validation cohort.

We developed and validated a nomogram to predict 3-year overall remission rate after MVD treatment of TN. The nomogram can be used in clinical trials to determine the likelihood of pain recurrence in TN patients treated with MVD for 3 years to aid in the comprehensive treatment of TN.

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Embolization of Brain Arteriovenous Malformations With VersusWithout Onyx Before Stereotactic Radiosurgery

Neurosurgery 88:366–374, 2021

Embolization of brain arteriovenous malformations (AVMs) using ethylene-vinyl alcohol copolymer (Onyx) embolization may influence the treatment effects of stereotactic radiosurgery (SRS) differently than other embolysates.

OBJECTIVE: To compare the outcomes of pre-SRS AVM embolization with vs without Onyx through a multicenter, retrospective matched cohort study.

METHODS: We retrospectively reviewed International Radiosurgery Research Foundation AVM databases from 1987 to 2018. Embolized AVMs treated with SRS were selected and categorized based on embolysate usage into Onyx embolization (OE + SRS) or non-Onyx embolization (NOE + SRS) cohorts. The 2 cohorts were matched in a 1:1 ratio using de novo AVM features for comparative analysis of outcomes.

RESULTS: The matched cohorts each comprised 45 patients. Crude AVM obliteration rates were similar between the matched OE + SRS vs NOE + SRS cohorts (47% vs 51%; odds ratio [OR] = 0.837, P = .673). Cumulative probabilities of obliteration were also similar between the OE + SRS vs NOE + SRS cohorts (subhazard ratio = 0.992, P = .980). Rates of post-SRS hemorrhage, all-cause mortality, radiation-induced changes, cyst formation, and embolization-associated complications were similar between the matched cohorts. Sensitivity analysis for AVMs in the OE + SRS cohort embolized with Onyx alone revealed a higher rate of asymptomatic embolization-associated complications in this subgroup compared to the NOE + SRS cohort (36% vs 15%; OR = 3.297, P = .034), but the symptomatic complication rates were similar.

CONCLUSION: Nidal embolization using Onyx does not appear to differentially impact the outcomes of AVM SRS compared with non-Onyx embolysates. The embolic agent selected for pre-SRS AVM embolization should reflect both the experience of the neurointerven- tionalist and target of endovascular intervention.

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Cranioplasty following ventriculoperitoneal shunting: lessons learned

Acta Neurochirurgica (2021) 163:441–446

Cranioplasty (CP) is considered as a straightforward and technically unchallenging operation; however, complication rates are high reaching up to 56%. Presence of a ventriculoperitoneal shunt (VPS) and timing of CP are reported risk factors for complications. Pressure gradients and scarring at the site of the cranial defect seem to be critical in this context. The authors present their experiences and lessons learned.

Methods A consecutive series of all patients who underwent CP at the authors’ institution between 2002 and 2017 were included in this retrospective analysis. Complications were defined as all events that required reoperation. Logistic regression analysis and chi-squared test were conducted to evaluate the complication rates according to suspected risk factors.

Results A total of 302 patients underwent cranioplasty between 2002 and 2017. The overall complication rate was 17.5%. Complications included epi-/subdural fluid collection (7.3%) including hemorrhage (4.6%) and hygroma (2.6%), bone graft resorption (5.3%), bone graft infection (2.0%), and hydrocephalus (5.7%). Overall, 57 patients (18.9%) had undergone shunt implantation prior to CP. The incidence of epi-/subdural fluid collection was 19.3% in patients with VPS and 4.5% in patients without VPS, OR 5.1 (95% CI 2.1–12.4). Incidence of hygroma was higher in patients who underwent early CP. Patients with temporary shunt ligation for CP did not suffer from complications.

Conclusion CP in patients with a VPS remains a high-risk procedure. Any effort to understand the pressure dynamics and to reduce factors that may trigger the formation of a large epidural space must be undertaken.

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