Neurosurgical Strategies Research Articles

Personalizing neurosurgical strategies for epidermoid cysts with artificial intelligence.

Personalizing neurosurgical strategies for epidermoid cysts with artificial intelligence.

Peripheral Nerve Injuries: The Recent Surgical Management Strategies

Objectives: Numerous individuals with peripheral nerve injuries (PNIs) have permanent disability, which is a major health concern. There are a number of potential causes of PNIs, including piercing injuries, compression, stretch, and ischemia. These injuries can present with a variety of clinical symptoms. Methodology: In order to clarify the many forms of injury, the peripheral nerve's anatomy is thoroughly explained in this review, which attempts to revisit key PNI ideas. In addition, the specific pathophysiological processes that follow a peripheral nerve damage and the related variables that might either support or undermine the body's ability to regenerate itself depending on PNIs classifications are also mentioned. Next, the recent therapeutic neurosurgical approaches that are accessible in cases of PNIs are described. Results: Following our overview of the previous literatures on neurosurgical strategies for the management of PNIs, we can observe that surgical procedures are unfortunately very expensive and that their use has been limited due to a variety of adverse effects, such as immunosuppression, chromosomal abnormalities, and tumorigenicity. Conclusion: In accordance with the source, location and extent of the injury, there are currently advantages to treating PNIs with both surgical and non-surgical approaches. These days, it is possible to identify innovative techniques with the aid of good information regarding incidences, existing practice, outcomes, and study types. Despite a great deal of research on this topic, full functional recovery is still a problem that has to be solved.

Decompressive Craniectomy: From Ancient Practices to Modern Neurosurgery.

Decompressive craniectomy (DC) is a neurosurgical strategy that expels a parcel of the cranium to relieve pressure on a swollen or herniating brain. This review article explores the history of DC, from its ancient roots in trepanning to its contemporary applications. It then examines the mechanisms by which DC reduces intracranial pressure (ICP) and improves cerebral blood flow. The article highlights the efficacy of DC in treating patients with severe traumatic brain injury (TBI), stroke, and other conditions that cause increased ICP. However, it also acknowledges the potential complications of DC, such as infection and bleeding. The ethical considerations surrounding DC are explored in detail, particularly the challenging decision-making process for patients who are unable to give consent. A specific focus is given to the use of DC in pediatric patients, where the developing brain is especially vulnerable to pressure changes.

SURG-01. ULTRA-FAST DEEP-LEARNED CNS TUMOR CLASSIFICATION USING STURGEON; THE IMPACT ON STRATEGY FOR THE PEDIATRIC NEUROSURGEON

Abstract INTRODUCTION Central nervous system tumors still represent one of the most challenging fields to create curation in pediatric oncology. The primary treatment always starts with a neurosurgical intervention to obtain tumor tissue for diagnosis. In most cases this intervention is a maximal safe resection of the tumor. The oncological prognostic value of extent of resection is determined by the precise molecular diagnosis and per-operative ultra-fast molecular classification of central nervous tissue provides the neurosurgeon relevant information for choosing the right strategy. This per-operative molecular diagnosis determines the balance between the need of radicality versus the prevention of neurological morbidity in the individual patient. We shall report on our neurosurgical experiences with the per-operative use of Sturgeon in our national practice of pediatric neuro-oncology in the Netherlands. METHODS The ultra-fast AI-based nanopore sequencing method, Sturgeon, has been implemented as per-operative diagnostic in most neurosurgical tumor resections in our center (1). An overview of our nanopore sequencing pipe- and timeline will be presented and its impact on neurosurgical strategies will be shared. RESULTS Reliable and accurate diagnoses can be obtained within 40 minutes after starting sequencing in 45 out of 50 retrospectively sequenced samples (while abstaining from diagnosis of the other 5 samples). The implementation in real time surgery results in a turnaround time between taking out sample material to diagnosis in less than 90 minutes. The most important result is that there is a high sensitivity and virtually no false positives since it is refraining from diagnosis when there is too much uncertainty. Several illustrative cases with impact on the neurosurgical strategy have been collected. CONCLUSION Ultra-fast deep-learning CNS tumor classification using Sturgeon is feasible. Results of per-operative implementation illustrate the impact on neurosurgical strategy. 1. Ultra-fast deep-learned CNS tumour classification during surgery. Vermeulen C et al. Nature. 2023 Oct;622(7984):842-849.

MDB-11. DOES THE INTRAOPERATIVE ASSESSMENT OF SITE OF ORIGIN OF MEDULLOBLASTOMA ALLOW FOR A TAILORING OF THE NEUROSURGICAL STRATEGY? DATA FROM A RETROSPECTIVE SINGLE-CENTER ASSESSMENT AND PROPOSAL OF A PROSPECTIVE MULTICENTER STUDY

Abstract BACKGROUND Developmental gene expression data from medulloblastoma (MB) suggest that WNT-MB originate from the region of the embryonic lower rhombic lip (LRL), whereas SHH-MB and non-WNT/non-SHH MB arise from cerebellar precursor matrix regions. This study aims to analyze detailed intraoperative data with regard to the site of origin (STO) and compare these findings with the hypothesized regions of origin associated with the molecular group. METHODS A review of the institutional database identified 58 out of 72 pediatric patients who were operated on a MB at our department between 1996 and 2020 that had a detailed operative report, surgical video as well as clinical and genetic classification data available for analysis. The STO was assessed based on intraoperative findings. RESULTS Using the intraoperatively defined STO, “correct” prediction of molecular groups was feasible in 20% of WNT-MB, 60% of SHH-MB and 71% of non-WNT/non-SHH MB. The positive predictive values of the neurosurgical inspection to detect the molecular group were 0.21 (95% CI 0.08–0.48) for WNT-MB, 0.86 (95% CI 0.49–0.97) for SHH-MB and 0.73 (95% CI 0.57–0.85) for non-WNT/non-SHH MB. CONCLUSION In our series of 58 well-documented cases, the intraoperative assessment of the STO could not reliably predict the molecular group. Thus, the current evidence does still not allow for intraoperative group-specific risk stratification that would enable tailoring the neurosurgical strategy to the prognostic and predictive profile of the patient. Prospective multicenter assessments are necessary to systematically evaluate the growth pattern and site of origin of medulloblastoma. Accordingly, a study protocol of an international cohort study will be presented.

PATH-01. ACCURATE AND RAPID PAEDIATRIC BRAIN TUMOR CLASSIFICATION (PBT) BY METHYLATION PROFILING USING NOVEL NATIVE REAL TIME OXFORD NANOPORE TECHNOLOGY SEQUENCING TECHNOLOGY

Abstract BACKGROUND Pediatric brain tumors (PBTs) pose a significant challenge being the leading cause of cancer related mortality in children. The existing classification process is time-consuming and fails to capture the heterogeneity of PBTs. Urgent advancements in diagnostic and therapeutic approaches are needed. The WHO classification 5th edition for CNS tumors introduced DNA methylation analysis into the diagnostic process, especially for difficult-to-diagnose cases. However, the currently available DNA methylation array-based methods are laborious, costly, &require large amounts of DNA METHODS Nanopore methylation analysis is rapid, accurate, and inexpensive & requires minimal tissue. We applied this technology on 24 PBT samples that were classified into ten molecular subgroups. RESULTS Our results were compatible with those obtained through Heidelberg methylation analysis, standard histopathological examination, and molecular tests and were in concordance with the final neuro-pathological diagnosis. Moreover, for five prospective cases, that would have challenged standard methods, Nanopore yielded same-day results, guiding additional tests and providing a significant diagnostic advantage. In one case, a 2.2-year-old male, with a large left parieto-temporal tumor and a suprasellar lesioninitially treated elsewhere with upfront chemotherapy without biopsy, developed clinical deterioration. We resected the temporal lesion and frozen tissue diagnosis suggested low-grade glioma. However, same day Nanopore sequencing analysis indicated a high score for ‘Meningioma’. Final pathology examination 10 days later confirmed ‘‘Atypical meningioma, WHO grade 2” – an extremely rare diagnosis in this age group. Visual deterioration prompted immediate resection of the second lesion before final pathological confirmation. Thus, early Nanopore classification played a vital role in diagnosis and management. CONCLUSIONS Our preliminary results underscore the potential of Nanopore potential for accurate and rapid PBT classification from small brain biopsies, with DNA input as low as 100 nanograms. This cutting-edge technology promises to substantially reduce time to diagnosis, shaping future neurosurgical strategies for individualized PBT patient management.

1134 A Call to Revise the Thirty-year-old SRS Dose Guidelines for Brain Metastases

INTRODUCTION: Stereotactic Radiosurgery (SRS) currently is the most widely used neurosurgical strategy for treatment of brain metastases. Many centers still rely on 30-year-old dose volume guidelines derived from RTOG 90-05. METHODS: Between 2014 and 2020 330 NSCLC patients (median age = 65 years) with 2910 brain metastases underwent Gamma knife SRS. The number of tumors treated per patient ranged from 1-56 and the total tumor cumulative volume ranged from .05 to 33.09 cc (median = 3.17). The median prescribed tumor margin dose was 18 Gy. RESULTS: Median overall survival after radiosurgery was 15.5 months. Radiological tumor progression was noted 66 out of 2910 tumors (2.27%) in 51 out of 330 patients (15.45%). Tumors were divided into 4 categories based on tumor volumes (<1.5 cc, 1.5-<5 cc, 5-<10 cc, and = 10cc). The effect of margin dose, and % tumor covered in 18 Gy, 20 Gy, and 24 Gy on local tumor control was analyzed for all 4 categories. In tumors with volumes >1.5 cc local tumor control was significantly better (P < 0.05) when =65% of the tumor volume received at least 24 Gy. No relationship was found between tumor control and 75, 90, and 100 % volumes receiving 18 or 20 Gy. CONCLUSIONS: In this study neither conformality of dose delivery nor tumor margin doses were the most important predictors of local tumor control as long as =65% of the tumor volume received at least 24 Gy. This finding can serve as a prescriptive guideline that allows margin doses below the RTOG guidelines, reduces reliance on strict conformality, and improves tumor control.

OS08.7.A DEPRESSIVE SYMPTOMS IN ASSOCIATION WITH TUMOR LOCATIONS AT DIAGNOSIS IN PATIENTS WITH DIFFUSE GLIOMA

Abstract BACKROUND Depressive symptoms are common in glioma patients and occur more frequent than in patients with other cancer types. The presence of tumors in specific brain regions that potentially disturb brain functions could contribute to this difference. These lesions may cause an inadequate emotional response to an incurable and lethal disease with consequences for patient counseling and neurosurgical strategies. In this study, we examine the association between brain tumor location and depressive symptoms at presentation in patients with diffuse glioma using several methods for lesion symptom mapping. MATERIAL AND METHODS The retrospective cohort consisted of patients with diffuse glioma who had a preoperative MR-scan and completed the Center for Epidemiologic Studies Depression scale (CES-D) before treatment. We classified patients based on unexpectedly low ( ≤6), intermediate (7-20) and unexpectedly high (>20) CES-D scores. Tumors were segmented in 3D and corresponding white matter disconnectomes were derived from normative tractography. We first correlated tumor and disconnectome with CES-D using sparse canonical correlation analysis to identify clusters of associated brain voxels. Next, we assessed the association between tumor locations and CES-D category using Bayesian multivariable categorical regression analysis of patient and tumor characteristics, including the overlap of tumors and disconnectomes with specific brain atlas structures, the probability of disconnection of white matter tracts, and functional network changes in local efficiency and eigenvector centrality. RESULTS We included 201 patients with a median age of 45 years (range 18-81), consisting of 62% males and 29% grade 4 gliomas. CES-D was completed a median of three weeks before surgery, was unexpectedly low in 29% and unexpectedly high in 15% of patients. Tumors located in the left (L) pallidum and right (R) thalamus were related to unexpectedly low CES-D, whereas tumors in the L hippocampus, L nucleus accumbens and R putamen were related to unexpectedly high CES-D. Disconnection of the R temporal subsection of the cingulum bundle, L optic radiation, L superior longitudinal fasciculus I and L uncinate fasciculus (UF) were related to unexpectedly low CES-D, whereas disconnection of the R corticospinal tract, R fornix, and L UF were related to unexpectedly high CES-D. Neither voxel clusters nor network measures were associated with CES-D. CONCLUSION Both unexpectedly low and unexpectedly high depressive symptom burden is common in patients with diffuse glioma at presentation. These dysfunctional emotional responses may be associated with the location of the tumor. Awareness of this phenomenon may be important in patient counseling and neurosurgical strategies. * these authors contributed equally

Developing an Individual Neurosurgical Strategy in Patients With a Two-Level Cervical Degenerative Disc Disease

Background: Little is written about substantiated clinical and biometric indications for dynamic stabilization, rigid fixation, and their combinations in patients with two-level degenerative disease of the cervical intervertebral discs (IVD).Objective: To study the risk factors for poor outcomes of two-segment interventions (total disk arthroplasty, TDA; anterior cervical discectomy and fusion, ACDF; and their combination) in patients with two-level degenerative diseases of the cervical IVD; to develop a custom clinical and instrumental assessment strategy for future interventions.Materials and methods: We retrospectively analyzed the outcomes in 118 patients with a two-level degenerative disease of the cervical IVD, who underwent TDA (n = 37), ACDF (n = 41), and their combination (n = 40) from 2005 to 2015. After this analysis, we built a mixed effects logistic regression model to identify and assess the impact of various risk factors on poor clinical outcomes in each intervention.Results: TDA correlated with favorable outcomes in patients with cervical lordosis over 12 °; I–III grade IVD changes according to Pfirrmann scale; I–II grade facet joints (FJ) changes according to Pathria criteria; no FJ tropism; segmental movements amplitude > 8 °; interbody space height ≤ 6 mm, and with no central spinal stenosis/spine interventions. Favorable ACDF outcomes may be achieved in patients with cervical lordosis ≥ 7 °; more than III grade IVD changes according to Pfirrmann scale; more than II grade changes in FJ according to Pathria criteria; segmental movements amplitude ≤ 8 °; interbody space height < 6 mm. FJ tropism, central spinal stenosis, and history of spine interventions do not affect ACDF outcomes.Conclusions: An individual approach to TDA, ACDF, and their combination as well as comprehensive preoperative clinical and instrumental assessment in patients with a two-level degenerative IVD disease contribute to the effective resolution of existing neurological symptoms, which reduced the pain severity in the cervical region and upper limbs, improve the patients’ functional status and quality of life in the late postoperative period, and reduce the number of postoperative complications and reinterventions.

Full cervical cord tractography: A new method for clinical use.

Despite recent improvements in diffusion-weighted imaging, spinal cord tractography is not used in routine clinical practice because of difficulties in reconstructing tractograms, with a pertinent tri-dimensional-rendering, in a long post-processing time. We propose a new full tractography approach to the cervical spinal cord without extensive manual filtering or multiple regions of interest seeding that could help neurosurgeons manage various spinal cord disorders. Four healthy volunteers and two patients with either cervical intramedullary tumors or spinal cord injuries were included. Diffusion-weighted images of the cervical spinal cord were acquired using a Philips 3 Tesla machine, 32 diffusion directions, 1,000 s/mm2 b-value, 2 × 2 × 2 mm voxel size, reduced field-of-view (ZOOM), with two opposing phase-encoding directions. Distortion corrections were then achieved using the FSL software package, and tracking of the full cervical spinal cord was performed using the DSI Studio software (quantitative anisotropy-based deterministic algorithm). A unique region of avoidance was used to exclude everything that is not of the nervous system. Fiber tracking parameters used adaptative fractional anisotropy from 0.015 to 0.045, fiber length from 10 to 1,000 mm, and angular threshold of 90°. In all participants, a full cervical cord tractography was performed from the medulla to the C7 spine level. On a ventral view, the junction between the medulla and spinal cord was identified with its pyramidal bulging, and by an invagination corresponding to the median ventral sulcus. On a dorsal view, the fourth ventricle—superior, middle, and inferior cerebellar peduncles—was seen, as well as its floor and the obex; and gracile and cuneate tracts were recognized on each side of the dorsal median sulcus. In the case of the intramedullary tumor or spinal cord injury, the spinal tracts were seen to be displaced, and this helped to adjust the neurosurgical strategy. This new full tractography approach simplifies the tractography pipeline and provides a reliable 3D-rendering of the spinal cord that could help to adjust the neurosurgical strategy.

SURG-09. Hypothalamic involvement in pediatric craniopharyngiomas;how to define and to realize optimal neurosurgical resections

Abstract The optimal neurosurgical strategy for pediatric craniopharyngiomas is on debate with shifts from gross total resection to limited resections in combination with local radiotherapy. The most relevant question underlying this ongoing discussion is how to prevent additional surgical morbidity to the hypothalamus. Limited neurosurgical resection in combination with local radiotherapy has been proved a safe alternative to gross total resection concerning tumor control. Pre-operative anatomical grading of hypothalamic involvement has been proposed by Puget et al using MRI discriminating between no hypothalamic involvement (grade 0), hypothalamic displacement (grade 1), and hypothalamic disruption (grade 2). Subsequently, post-operative hypothalamic damage can also be assessed on post-op MRI by the grading of the Vile et al in no discernable damage (grade 0), abnormality of floor of third ventricle (grade 1), or damaged or deficient floor of third ventricle (grade 2). Three questions remain to be settled: 1. How to define pre-operatively the extent of resection 2. How to realize per-operatively the intended limited resection, and three. How to determine post-operatively the (additional) surgical damage to the hypothalamus. We retrospectively evaluated a series of 25 children with craniopharyngioma being resected in our center from June 2018 until January 2022, with pre- and post-operative grading of hypothalamic involvement. In total 11 patients were downgraded on the post-operative compared to the pre-operative scale; either by 1 grade (n=6) or by 2 grades (n=5). These findings illustrate that the preoperative grading score does not always represent the actual hypothalamic involvement. This complicates the definition of limited surgery pre-operatively and illustrates the importance of both how to integrate per-operative findings in the realization of the intended limited resection and how to evaluate hypothalamic damage caused by tumor growth versus neurosurgical intervention. A more detailed treatment algorithm will be discussed.

Neurosurgical Treatment of Patients with Posterior Fossa Acute Subdural Hematoma Right after Cardiac Surgery.

As posterior fossa acute subdural hematoma (ASDH) right after cardiac surgery is extremely rare, the clinical course and optimal treatment strategy remain undetermined. We performed a retrospective analysis of patients with posterior fossa ASDH right after cardiac surgery requiring neurosurgical treatment at our institution over a 7-year period and, in this study, discussed the neurosurgical strategy and clinical course. Collected data included clinical history, laboratory results, time course, symptoms, neurosurgical treatment, outcome at discharge, and imaging studies. All six patients were women who had no history of head trauma and had received antithrombotic therapy during the perioperative period of cardiac surgery. All patients showed lower platelets count and were diagnosed with ASDH within 3 days (longest time 64 h) right after cardiac surgery. After discontinuation of anticoagulation therapy and administration of reversal agents, they underwent emergency hematoma evacuation craniotomy (n = 5) or burr hole drainage surgery (n = 1), which were performed in the prone (n = 4) or lateral (n = 2) positions. Four of these patients showed favorable outcomes, and two showed poor outcomes. One of the poor-outcome patients received three antithrombotic therapies, and another developed rapidly progressive ASDH. Posterior fossa ASDH associated with antithrombotic therapy right after cardiac surgery is frequently found in women, and emergent neurosurgical treatment with anticoagulation discontinuation and reversal agent administration can be performed safely. Burr hole drainage surgery might be acceptable in nonsevere cases. By contrast, we must pay attention to cases receiving both anticoagulant and antiplatelet drugs and rapid progression cases.

Management dilemmas in Nocardia brain infection.

Brain nocardiosis is a rare but severe infection mostly occurring among immunocompromised patients. In this review, we present recent data on this infection and address some of the common clinical dilemmas encountered in patients with brain nocardiosis. Strategies used to approach a patient with suspected brain nocardiosis include the 'conservative strategy' (without early neurosurgery) and the 'neurosurgical strategy' (with early aspiration or excision of brain abscess[es]). The advantages and disadvantages of both strategies are summarised. Our opinion is that the use of the 'conservative strategy' should be limited to well-selected patients presenting with an easily accessible extra-neurological lesion(s) and have brain abscesses at low risk of treatment failure. In terms of antimicrobial therapy, we summarise the data supporting the use of a multidrug regimen in patients with brain nocardiosis.Last, we list possible reasons for treatment failure in patients with brain nocardiosis and suggest interventions to overcome them. Literature is scarce regarding brain nocardiosis, as a consequence of the rarity of this disease. A multidisciplinary and individualised management is required to optimise the outcome of patients with brain nocardiosis.

Intraoperative DNA methylation classification of brain tumors impacts neurosurgical strategy

Intraoperative DNA methylation classification of brain tumors impacts neurosurgical strategy

Intraoperative DNA methylation classification of brain tumors impacts neurosurgical strategy.

BackgroundBrain tumor surgery must balance the benefit of maximal resection against the risk of inflicting severe damage. The impact of increased resection is diagnosis-specific. However, the precise diagnosis is typically uncertain at surgery due to limitations of imaging and intraoperative histomorphological methods. Novel and accurate strategies for brain tumor classification are necessary to support personalized intraoperative neurosurgical treatment decisions. Here, we describe a fast and cost-efficient workflow for intraoperative classification of brain tumors based on DNA methylation profiles generated by low coverage nanopore sequencing and machine learning algorithms.MethodsWe evaluated 6 independent cohorts containing 105 patients, including 50 pediatric and 55 adult patients. Ultra-low coverage whole-genome sequencing was performed on nanopore flow cells. Data were analyzed using copy number variation and ad hoc random forest classifier for the genome-wide methylation-based classification of the tumor.ResultsConcordant classification was obtained between nanopore DNA methylation analysis and a full neuropathological evaluation in 93 of 105 (89%) cases. The analysis demonstrated correct diagnosis in 6/6 cases where frozen section evaluation was inconclusive. Results could be returned to the operating room at a median of 97 min (range 91-161 min). Precise classification of the tumor entity and subtype would have supported modification of the surgical strategy in 12 out of 20 patients evaluated intraoperatively.ConclusionIntraoperative nanopore sequencing combined with machine learning diagnostics was robust, sensitive, and rapid. This strategy allowed DNA methylation-based classification of the tumor to be returned to the surgeon within a timeframe that supports intraoperative decision making.

Recent developments in the treatment of Parkinson's Disease.

Parkinson’s disease (PD) is a common neurodegenerative disease typified by a movement disorder consisting of bradykinesia, rest tremor, rigidity, and postural instability. Treatment options for PD are limited, with most of the current approaches based on restoration of dopaminergic tone in the striatum. However, these do not alter disease course and do not treat the non-dopamine-dependent features of PD such as freezing of gait, cognitive impairment, and other non-motor features of the disorder, which often have the greatest impact on quality of life. As understanding of PD pathogenesis grows, novel therapeutic avenues are emerging. These include treatments that aim to control the symptoms of PD without the problematic side effects seen with currently available treatments and those that are aimed towards slowing pathology, reducing neuronal loss, and attenuating disease course. In this latter regard, there has been much interest in drug repurposing (the use of established drugs for a new indication), with many drugs being reported to affect PD-relevant intracellular processes. This approach offers an expedited route to the clinic, given that pharmacokinetic and safety data are potentially already available. In terms of better symptomatic therapies that are also regenerative, gene therapies and cell-based treatments are beginning to enter clinical trials, and developments in other neurosurgical strategies such as more nuanced deep brain stimulation approaches mean that the landscape of PD treatment is likely to evolve considerably over the coming years. In this review, we provide an overview of the novel therapeutic approaches that are close to, or are already in, clinical trials.

Low recurrence after Simpson grade II resection of spinal benign meningiomas in a single-institute 10-year retrospective study

The objective of this study was to more fully understand the optimal neurosurgical strategy for spinal benign meningiomas from a medium to long-term perspective. This retrospective study included a cohort of 35 patients with a diagnosis of spinal meningioma who were first operated at our institute over the past 10 years and followed-up for at least 2 years after surgery. The inclusion criterion for the study was the pathological diagnosis finally verified as benign meningioma of World Health Organization (WHO) grade 1. The average follow-up duration after surgery was 61.0 months. The location of the spinal meningioma was classified into ventral or dorsal type based on the operative video record and the preoperative MR images. The extent of resection of the spinal meningioma was carefully determined based on the Simpson grade. The average neurological condition was significantly improved at the final follow-up. Simpson grade I or II resection was achieved in 31 of 35 cases (88.6%). No Simpson grade I or II cases showed local recurrence during follow-up. Tumor recurrence was noted in 2 of 4 cases of Simpson grade IV resection. One case has been followed-up without any re-operation because of no neurological deterioration, and the other case underwent stereotactic radiosurgery. This study suggested that meticulous Simpson grade II resection of spinal benign meningiomas of WHO grade 1 may be good enough from a medium to long-term follow-up perspective, though longer follow-up is absolutely necessary.

Neuroblastoma with intracerebral metastases and the need for neurosurgery: a single-center experience.

Intracerebral metastases in neuroblastoma patients are rare, and information about the indication for and the outcome of neurosurgical procedures in this setting is scarce in the literature. The authors' aim in the present study was to report a single-center experience with the neurosurgical treatment of intracerebral metastases in neuroblastoma. This study is a retrospective single-center analysis of all neurosurgical strategies used in the treatment of intracerebral metastases in neuroblastoma patients. Between 2009 and 2017, 237 pediatric patients (94 girls, 143 boys) with a mean age of 39 months at diagnosis were treated for neuroblastoma. Five (2.1%) of the 237 patients had a neurosurgical procedure for intracerebral metastases. The metastases occurred a mean of 46 months after initial diagnosis. All of these patients had neuroblastoma stage 4. Indications for surgery were recurrent metastases after initial successful oncological treatment or progression of the metastasis under oncological treatment as well as deterioration of neurological function. Intraoperatively, the tumor usually had a distinguishable dissection plane but was infiltrative to adjacent nerves in some spots. Mean overall survival after the neurosurgical procedure was 22 months. Furthermore, in another 3 patients, a neurosurgical procedure was done for an intracranial but extracerebral metastasis. Neurosurgical procedures for intracerebral metastases in neuroblastoma patients are rare and were performed in 2.1% of patients in the present study. Intracerebral metastases occurred during disease progression, and the prognosis after surgery was very limited. The main indications for surgery were rapid neurological deterioration or recurrence of the metastasis after initial successful oncological treatment. Intraoperatively, the metastases usually had a distinguishable dissection plane from the normal brain tissue.

The Neurosurgeons' Armamentarium for the Management of Refractory Post-Herpetic Neuralgia

Abstract INTRODUCTION Post-herpetic neuralgia (PHN) can be refractory to medical treatment. Its complex pathophysiology explains the numerous neurosurgical procedures available. The present study summarizes all available neurosurgical strategies for the management of resistant PHN and evaluates respective safety and efficacy. METHODS A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The PubMed and Cochrane Library databases were searched up to October 2018. RESULTS A total of 38 studies comprising 811 patients with refractory PHN were included. Ten studies with 243 patients reported use of spinal cord stimulation. The mean visual analog scale (VAS) score was 7.6 and 2.7 before and after the procedure. Dorsal root entry zone (DREZ) lesioning was performed in 85 patients. The mean VAS score before and after the procedure was 8.6 and 3.7. During the postoperative period, 42.3% of patients developed motor deficits. Five studies investigated intrathecal (IT) injections or pump insertions. The combined IT injections demonstrated a strong analgesic effect 87% of patients reported pain reduction >50%. Spinal trigeminal nucleotomy was reported in 4 studies with a total of 60 patients with 78.3% of patients pain-free during long-term follow-up. However, motor and sensory deficits occurred in 75% to 100%. DRG pulsed radiofrequency lesioning was reported by 2 studies (69 patients) with mean VAS before and after was 6.9 and 2.7, respectively. Peripheral nerve simulation was reported by 3 studies comprising 10 patients in total. This strategy was among the safest and most effective, demonstrating a VAS pain reduction from 8.6 to 2 without any complications. CONCLUSION Neurosurgical approaches for recalcitrant PHN include neuromodulatory and ablative procedures. Patients with resistant PHN should undergo minimally invasive procedures first, including SCS, PNS, or DRG radiofrequency lesioning. More invasive procedures should be reserved for refractory cases. Comparative studies are needed in order to construct a PHN neurosurgical management algorithm.

Intramedullary spinal cord ependymoma and astrocytoma: intraoperative frozen-section diagnosis, extent of resection, and outcomes.

OBJECTIVEThe intraoperative differentiation of ependymomas from astrocytomas is important because neurosurgical strategies differ between these two tumor groups. Previous studies have reported that the diagnostic accuracy of intraoperative frozen sections of intracranial central nervous system (CNS) tumors is higher than 83%-97%, whereas that for spinal intramedullary tumors remains unknown. Herein, authors tested the hypothesis that intraoperative frozen-section diagnosis is the gold standard for a differential diagnosis of intramedullary spinal cord tumors.METHODSThe clinical characteristics, intraoperative histological diagnosis from frozen sections, extent of tumor resection, progression-free survival (PFS), and overall survival (OS) of 49 cases of intramedullary spinal cord ependymomas (n = 32) and astrocytomas (n = 17) were retrospectively evaluated.RESULTSThe frozen-section diagnosis and final diagnosis with permanent sections agreed in 23 (72%) of 32 cases of ependymoma. Of the 9 cases of ependymoma in which the frozen-section diagnosis disagreed with the final diagnosis, 4 were incorrectly diagnosed as astrocytoma and the other 5 cases had a nonspecific diagnosis, such as glioma. Nonetheless, gross-total resection was achieved in 6 of these 9 cases given the presence of a dissection plane. The frozen-section diagnosis and final diagnosis agreed in 12 (71%) of 17 cases of astrocytoma. Of the 5 cases of astrocytoma in which the frozen-section diagnosis disagreed with the final diagnosis, 1 was incorrectly diagnosed as ependymoma and the other 4 had a nonspecific diagnosis. Gross-total resection was achieved in only 1 of these 5 cases.A relationship between the size of tumor specimens and the diagnostic accuracy of frozen sections was not observed. Ependymal rosettes and perivascular pseudorosettes were observed in 30% and 57% of ependymomas, respectively, but were absent in astrocytomas.Progression-free survival and OS were both significantly longer in cases of ependymoma than in cases of astrocytoma (p < 0.001). Gross-total resection was achieved in 69% of ependymomas and was associated with longer PFS (p = 0.041). In the astrocytoma group, gross-total resection was achieved in only 12% and there was no relationship between extent of resection and OS. Tumor grades tended to correlate with OS in astrocytomas (p = 0.079).CONCLUSIONSThe diagnostic accuracy of intraoperative frozen sections was lower for intramedullary spinal cord ependymomas and astrocytomas in the present study than that for intracranial CNS tumors reported on in the literature. Surgical strategies need to be selected based on multiple factors, such as clinical characteristics, preoperative imaging, frozen-section diagnosis, and intraoperative findings of the tumor plane.