OBJECTIVE:Hearing preservation in vestibular schwannoma (VS) surgery remains challenging due to frequent cochlear nerve displacement and the limited reliability of brainstem auditory evoked potentials (BAEPs) once waveforms deteriorate. This study evaluated the feasibility and clinical utility of bipolar handheld cochlear nerve action potential (CNAP) mapping for intraoperative nerve identification and compared its prognostic performance with BAEP monitoring. METHODS:In this retrospective single-center cohort, 193 patients with histologically confirmed VS underwent intraoperative auditory mapping between September 2021 and November 2024. Two color-coded bipolar handheld probes were used: one for facial nerve stimulation and the other for near-field CNAP recording along the presumed cochlear nerve course. CNAP responses were considered favorable if waveforms remained stable or decreased by < 50% in amplitude. Functional hearing preservation (American Academy of Otolaryngology-Head and Neck Surgery class A-C) served as the primary endpoint. Logistic regression and receiver operating characteristic (ROC) analyses evaluated predictive performance. RESULTS:CNAP mapping identified the cochlear nerve in 83.4% of cases, significantly higher than intraoperative BAEP elicitation (46.1%; p < 0.001). Favorable CNAP responses were strongly associated with hearing preservation (91.4% vs 8.1%, p < 0.001; adjusted OR 37.0, 95% CI 9.28-217.8). The combined CNAP + BAEP model showed excellent discrimination (area under the ROC curve = 0.91) and good calibration (p = 0.24, Hosmer-Lemeshow test). CONCLUSIONS:CNAP mapping enabled real-time functional localization of the cochlear nerve and provided complementary intraoperative functional information. While postoperative hearing remains dependent on the structural integrity of the cochlear nerve, particularly in large tumors, CNAP mapping provides complementary functional information strongly associated with hearing preservation.
M. Gazi Yaşargil, often called the "father of modern microneurosurgery," fundamentally reshaped neurosurgery through a philosophy emphasizing precision and functional preservation. Despite his widely acknowledged legacy, no comprehensive, data-driven analysis has consolidated the full scope of his clinical and scholarly impact. This study combines a narrative synthesis of Yaşargil's work with a bibliometric meta-analysis of his publications from 1952 to 2024, evaluating contributions across anatomical approaches, technical innovations, therapeutic strategies, surgical outcomes, and academic influence. Findings highlight foundational anatomical approaches, such as the pterional craniotomy, and key technical innovations, including specialized microsurgical instruments. His therapeutic strategies achieved durable outcomes, with > 90% obliteration rates in selected vascular cohorts and Engel class I seizure freedom in approximately 70% of epilepsy cases. Bibliometric analysis of 145 publications (approximately 15,089 citations) shows his sustained scholarly influence, with 2748 citations accrued since 2020, particularly in epilepsy and tumor research. This work underscores Yaşargil's enduring impact: anatomy-driven, transferable strategies that remain central to contemporary neurosurgical practice, even amid advances in robotics, endovascular techniques, and image guidance.
OBJECTIVE:Postoperative visual field deficits (VFDs) following anterior temporal epilepsy surgery often result from Meyer's loop (ML) injury. Optic radiation (OR) tractography aids surgical planning, but accuracy varies by method. Deterministic diffusion tensor imaging (Det-DTI) tractography underrepresents fiber complexity, whereas constrained spherical deconvolution with probabilistic tracking (Prob-CSD) resolves crossing fibers and improves anatomical fidelity. The aim of this study was to compare Det-DTI and Prob-CSD for OR/ML delineation and to evaluate accuracy by correlating tract injury with postoperative VFD severity. METHODS:Adults who underwent anterior temporal epilepsy surgery at two centers (Alfred Hospital in Melbourne, Australia; Vanderbilt University Medical Center in Nashville, Tennessee, US) were included. All patients underwent pre- and postoperative T1-weighted and diffusion-weighted MRI and automated postoperative perimetry. Det-DTI and Prob-CSD tractography pipelines, using the same expert-guided regions of interest, were compared. Tract injury was quantified as volumetric overlap between reconstructed ORs and resection cavities. VFD severity was measured as quadrant-specific visual field (QsVF) scores from perimetry. Reconstructed tract and estimated injury volumes were compared using the Wilcoxon signed-rank test, and their correlations with QsVF were assessed using Pearson correlation. Linear regression was used to assess whether Prob-CSD-estimated tract injury independently predicted postoperative QsVF, with resection volume and surgical technique as covariates. RESULTS:Overall, 33 patients (19 female, median age 39.1 years; 30 right handed and 11 left sided) were included in the analysis. Surgery comprised 9 anterior temporal lobectomies, 21 selective amygdalohippocampectomies, and 3 lesionectomies. Compared with Det-DTI, Prob-CSD tractography delineated significantly larger OR volumes (mean 20.18 ± 4.76 cm3 vs 1.48 ± 1.05 cm3; p = 8.34 ×10-7) and identified greater tract injury volumes (mean 0.60 ± 0.81 cm3 vs 0.04 ± 0.16 cm3; p = 3.7 ×10-6). Det-DTI failed to reconstruct ML in all but one case. Prob-CSD tract injury volumes correlated strongly with postoperative QsVF scores (r = -0.63, p = 7.35 ×10-5), whereas Det-DTI showed a weaker nonsignificant association (r = -0.31, p = 0.08). Linear regression confirmed independent association between Prob-CSD tract injury and postoperative VFD severity (p = 0.002, SE = 7.23 ×10-5, adjusted R2 = 0.34). CONCLUSIONS:Prob-CSD tractography outperformed Det-DTI in reconstructing ML and reliably predicting postoperative VFDs, regardless of surgical technique and resection extent. Det-DTI should be avoided for ML tractography. This study strongly supports incorporating expert-guided Prob-CSD into preoperative planning to enhance patient counseling and reduce risk of visual morbidity following temporal resection.
OBJECTIVE:Hydrocephalus can result from mass lesions for several reasons. Due to limited numbers of adult patients with mass lesions in studies that examine outcomes of endoscopic third ventriculostomy, success in this population is unclear. Additionally, the role of other ventriculoscopic procedures in the management of associated hydrocephalus is unclear. In this retrospective case series, the authors investigated optimal management strategies for patients with mass lesions and hydrocephalus. METHODS:A list of patients who underwent ventriculoscopic procedures or shunting procedures was compiled. Basic demographics, pathology, etiology of hydrocephalus, imaging, surgical procedures, complications, and long-term outcomes were obtained from the electronic medical record. Patients were subanalyzed in groups based on pathology, type of hydrocephalus, and initial management strategy. RESULTS:A total of 98 patients were identified. The most common pathologies causing hydrocephalus were gliomas, (n = 33, 33.67%), metastatic lesions (n = 17, 17.35%), pineal region tumors (n = 13, 13.27%), and cystic lesions (n = 13, 13.27%). Colloid cysts were excluded. Obstructive hydrocephalus was the most common cause of hydrocephalus (n = 102, 81.60%). All patients who presented with communicating hydrocephalus were treated with shunting. The long-term success of endoscopic approaches was 83.33%. Patients with gliomas and CNS lymphoma were least likely to be shunt free after endoscopic management. CONCLUSIONS:The etiology of hydrocephalus in patients with mass lesions is heterogeneous. Shunting is effective in patients with communicating hydrocephalus. Endoscopic management is successful in patients with obstructive hydrocephalus if their tumors do not have a propensity for leptomeningeal disease, such as high-grade gliomas or CNS lymphoma.
OBJECTIVE:Access to the posterior compartment of the cavernous sinus (CS) remains one of the greatest challenges via endoscopic endonasal surgery because of its deep location behind the posterior genu of the internal carotid artery (ICA) and the complex neurovascular ligamentous structures it contains. To date, no comprehensive anatomical study has focused specifically on the posterior compartment of the CS from the perspective of an endoscopic endonasal approach (EEA). The aim of this study was to delineate the microsurgical anatomy and technical nuances critical for safely accessing this compartment via the EEA. METHODS:Thirty-nine colored silicone-injected cadaveric heads were dissected, 19 via a transcranial approach and 20 via an EEA. Two illustrative surgical cases were also reviewed to highlight anatomical landmarks and strategies for tumor resection within the posterior compartment of the CS. RESULTS:The posterior compartment exhibited a triangular configuration in 66.7% of hemispheres and a quadrilateral shape in 33.3%, depending on the angulation of the ICA posterior genu. The posterior parasellar ligament was present in 64% of hemispheres, with 42% displaying a two-anchor configuration and 58% a net-like morphology. The posterior petroclinoid ligament, a dural fold marking the transition from the roof to the posterior wall of the CS, showed a smooth slope in 76% and ossification at attachment sites in 69%. Gruber's ligament, a periosteal dural extension from the posterior clinoid base to the petrous apex, appeared as a robust membranous band in 78% of hemispheres and as ossified in 59%. Potential spaces around Gruber's ligament may serve as key corridors for tumor invasion and remnants. Four venous outlets of the posterior compartment, draining into the basilar plexus, foramen lacerum plexus, inferior petrosal sinus, and superior petrosal sinus, were consistently identified. CONCLUSIONS:This study provides a systematic description of the posterior compartment of the CS from an EEA perspective, clarifying its ligamentous, arterial, and venous architecture and offering critical insights for safe and effective tumor resection.
OBJECTIVE:The aim of this study was to project the total neurosurgical workforce across African countries by 2030, quantify the impact of policy interventions, and assess capacity and infrastructure constraints on advanced subspecialization across the continent. METHODS:The authors utilized a discrete-time Markov pipeline model to track prospective candidates from medical graduation through training and retention. Data were sourced from the World Federation of Neurosurgical Societies, WHO, and pan-African surveys for workforce counts, attrition rates, and training capacity. The equipment readiness index (ERI) was developed to link infrastructure to the feasibility of subspecialization practice. Projections were simulated under 4 scenarios, including a policy pack intervention (scholarships, mentorship, equipment), with uncertainty quantified via Monte Carlo methods. A fractional logit model assessed the policy pack's effect on the projected female share of the workforce. RESULTS:The median baseline neurosurgeon count was 10 per country. Annually, at least 231 medical students express interest in neurosurgery; however, limited residency spots cause waiting lists to grow by approximately 154 applicants annually. ERI scores showed extreme variability; only Egypt (0.81) surpassed the highest subspecialization threshold, while 21 countries scored below 0.10, severely curtailing advanced practice feasibility if there is no intervention. Under the baseline scenario, the workforce is projected to reach 5888 by 2030 (43.1% increase). The policy pack scenario yielded 8809 neurosurgeons (a 49.6% increase over baseline). The policy pack positively impacted the female share (median OR 1.28, 95% CI 1.01-1.61; p = 0.04); however, higher ERI was not a significant predictor. CONCLUSIONS:The African neurosurgical workforce faces binding constraints from limited training capacity and poor infrastructure readiness. Targeted policy interventions can power equitable growth.
OBJECTIVE:Precise characterization of glioblastoma (GBM) location is essential for prognosis and surgical planning. The aim of this study was to evaluate whether voxel-based analysis with the Brain-Grid (BG) system can provide prognostic insights by quantifying tumor invasiveness and spatial distribution. METHODS:The authors retrospectively analyzed 116 adult patients who underwent treatment for newly diagnosed IDH-wildtype GBM. Tumors were classified on preoperative MRI using the BG system. Clinical, radiological, and molecular variables, including MGMT promoter methylation, were correlated with overall survival (OS), progression-free survival, and functional outcomes. RESULTS:The mean patient age was 63.5 ± 9.7 years. The mean OS was 14.4 ± 8.86 months (maximum 53 months). The mean number of infiltrated BG voxels was 5.8 ± 3.1 (median 5, IQR 3-8; maximum 14). Patients with ≥ 6 voxels had shorter OS (p = 0.012). Tumors most often involved the A2-C2-S2 and A2-C2-S3 voxels (where "A" indicates "axial," "C" indicates "coronal," and "S" indicates "sagittal"), corresponding to the basal ganglia and subventricular zone. Right-sided tumors were most common; posterior localization was associated with better survival (area under the curve = 0.71). Resection in the A2-C2-S3 voxel correlated with improved OS (p = 0.03). The median preoperative tumor volume was 38.74 cm3; higher pre- and postoperative volumes and lower extent of resection (EOR) predicted worse prognosis (p = 0.012, p = 0.001, and p = 0.002, respectively). MGMT methylation showed no significant correlation with OS (p = 0.15) or voxel distribution. CONCLUSIONS:Voxel-based analysis with the BG system enables quantitative and qualitative characterization of GBM topography. Invasiveness, tumor burden, and EOR were key predictors of survival, while MGMT methylation had limited spatial prognostic value. Incorporating voxel count into preoperative evaluation may enhance prognostic stratification and surgical planning in GBM.
Eugène-Louis Doyen studied medicine in Reims and Paris, further refining his surgical approach through experiences in Heidelberg, Würzburg, and Vienna. Recognized in French surgery for his innovations across thoracic, abdominal, and gynecological disciplines, his critical contributions to early neurosurgery, particularly trigeminal neuralgia treatment, remain significantly underexplored. Combining elements from the Hartley-Krause subtemporal route and the Rose sphenoidal route, he developed an advanced trigeminal ganglionectomy technique to minimize complications. Doyen introduced the electric craniotome, instruments specifically designed for dural detachment, and specialized devices to enable precise en bloc ganglion removal, thereby enhancing surgical safety and efficiency. He developed a minimally invasive retrosigmoid craniotomy approach using a speculum and custom neurotome to sever the sensory trigeminal root. This groundbreaking cerebellopontine angle endoscopy technique substantially reduced invasiveness compared to more extensive gasserectomy procedures. Despite the considerable controversy stemming from his abrasive personality, unorthodox methods, and provocative practices, such as filming surgical procedures, Doyen's bold innovations advanced neurosurgical techniques at the turn of the 20th century. Examining his career offers essential insights into a pivotal transitional era when ambitious operations on the brain began evolving into more precise, organized, and effective neurosurgical practices.
OBJECTIVE:Resections of the supplementary motor area (SMA) in the dorsomedial frontal cortex (DMFC) have traditionally been thought to result in predictable postoperative motor deficits termed the "SMA syndrome." However, the true incidence, etiology, and duration of these deficits seem overstated in the modern era. Herein, the authors aimed to critically evaluate and reassess the SMA syndrome in the context of surgical navigation, retractorless surgery, and contemporary motor mapping and monitoring techniques. METHODS:The authors retrospectively reviewed the electronic medical records of all patients who underwent DMFC resections for tumors or epilepsy between 2004 and 2025 at a single institution. Patients with insufficient data were excluded from the study. Compiled data included demographics, presenting symptoms, surgical characteristics, intraoperative mapping, postoperative motor function, postoperative complications, and follow-up visits up to 12 weeks. RESULTS:Eighty patients were eligible for study inclusion. New postoperative motor deficits occurred in 33.8% of patients (27/80); however, when cases with concomitant involvement of the primary motor cortex or cingulate gyrus were excluded, the incidence of SMA-specific deficits was only 10.0% (8/80). Moreover, 81.5% of new deficits (22/27) resolved by a median of 13 days, and 51.9% (14/27) recovered very rapidly. Patients with new deficits were more likely to have right hemisphere resections (p = 0.033). Motor strip involvement (p = 0.019) and postoperative complications (p = 0.042) were also associated with new deficits. No association was found with the use of intraoperative mapping, percentage of resected SMA, or other clinical characteristics. As expected, patients with new deficits experienced a longer postoperative hospital course (p = 0.023) and were more often discharged to inpatient rehabilitation (p = 0.012). Permanent deficits occurred in 6.3% of patients (5/80) and were more often associated with preoperative weakness (p = 0.047) and a major postoperative complication (p = 0.013). CONCLUSIONS:These findings challenge the classic perspectives on SMA syndrome. When resections are confined to the SMA, postoperative deficits are uncommon, mild, and resolved rapidly. Persistent deficits reflect injury to adjacent eloquent regions rather than injury from the SMA resection itself. With gravity-based retraction, modern navigation, and functional mapping, DMFC lesions can be resected more safely than in the past. Study findings support redefining SMA syndrome and expanding the role of mapping-guided resections in this region.
OBJECTIVE:Spontaneous intracranial hypotension (SIH) is an increasingly recognized disease entity presenting with a range of symptoms, the most common of which is orthostatic headaches. Bern scores have been validated to determine the probability of SIH on brain MRI. Spinal CSF leaks represent an important underlying etiology, with approximately 20% caused by CSF-venous fistulas (CVFs), or type III CSF leaks. Surgical ligation of CVFs is a reliable treatment option. The purpose of this study was to evaluate the outcomes of surgical ligation of CVFs and determine predictors of good outcomes. METHODS:This study was a retrospective review of prospectively collected data for all consecutive patients treated with nerve root ligation at the authors' institution between October 2021 and January 2025. Patient data were analyzed regarding improvement in preoperative symptoms, postoperative outcomes, quality of life, and any complications. RESULTS:Twenty-six patients underwent surgery for CVFs with a median follow-up of 12 (IQR 5.5-18.5) months. Twenty-two (84.6%) of 26 patients showed improvement in preoperative symptoms, with 94% showing an improvement in the Bern score at the last follow-up evaluation. Only 1 patient developed radicular pain severe enough to require further intervention, and there were no other complications reported. At last follow-up, 83.3% of patients were able to return to work. The overall preoperative Bern score was significantly correlated with postoperative outcomes. Last, self-evaluated quality of life outcomes were significantly correlated with preoperative Bern scores. CONCLUSIONS:Nerve root ligation is a safe and effective treatment option, and overall Bern score and venous congestion were predictive of postoperative outcomes and quality of life.
OBJECTIVE:Mild traumatic brain injury (mTBI) accounts for the majority of TBI cases. In polytrauma patients admitted to intensive care units (ICUs), mTBI may be associated with more severe clinical profiles and a higher risk of intervention. However, the outcomes and characteristics of this population remain underdescribed. METHODS:The authors conducted a retrospective study of adult patients with mTBI (Glasgow Coma Scale [GCS] score ≥ 13) admitted to the ICU of a level I trauma center from 2011 to 2017. Patients with secondary neurological deterioration prior to ICU admission were excluded. The authors specifically assessed the presence of intracranial lesions, need for neurosurgical interventions, and clinical outcomes including in-hospital mortality. Statistical analyses included descriptive statistics, univariate comparisons, and multivariate logistic regression models to identify factors independently associated with neurosurgical intervention and mortality. RESULTS:Among 244 patients (82% male, mean age 41.3 years), 82.8% had traumatic intracranial lesions. Neurosurgical intervention was required in 22.1% of cases, and the mortality rate was 3.3%. Subarachnoid hemorrhage, subdural hematoma, and epidural hematoma were the most common imaging findings. Independent predictors of neurosurgical intervention included epidural hematoma, midline shift > 5 mm, and assault-related trauma. Mortality was associated with age and hemorrhagic shock. Functional outcomes were favorable in most patients, but 24% had disability at discharge. CONCLUSIONS:In polytrauma patients admitted to the ICU, mTBI is often accompanied by intracranial injuries and a substantial need for surgical intervention, even when the GCS score is high.
OBJECTIVE:Satisfactory facial nerve (FN) and hearing preservation rates associated with modern vestibular schwannoma (VS) surgery potentially reflect the surgeon's expertise established over years. While advanced MRI can estimate cranial nerve topography and tumor traits, radiological predictors of postoperative functional outcomes across three standard surgical approaches remain unclear. The aim of this study was to address this gap by determining independent radiological predictors of FN and hearing outcomes, stratified by surgical approach, while considering the influence of the surgeon learning curve stage. METHODS:The authors retrospectively reviewed patients with VS who underwent resection between July 2012 and July 2023 at their institution. Potential radiological predictors of postoperative hearing and FN results were examined using multivariate regression analysis. To examine the learning curve impact on FN and hearing outcomes, the first 100 and first 24 operated cases, respectively, were compared with the most recent cases. RESULTS:There were 187 patients (103 female, median age 52 years) included in this analysis. The median tumor size and fundal CSF space (FCS) horizontal diameter were 17.7 mm and 3.2 mm, respectively. MRI revealed FCS presence in 67.9%, T2-weighted hyperintensity in 44.9%, and heterogeneous contrast enhancement in 28.8% of patients. Intraoperative FN monitoring (IOFM) showed favorable responses in 77.1% of patients, and V-wave preservation was confirmed by auditory evoked potential monitoring in 33.9%. The gross-total resection (GTR) rate was 66.3%. Favorable FN functional outcomes were observed in 73.3%, 83.3%, and 86.8% of patients at early, short-term, and long-term postoperative evaluations, respectively, with favorable IOFM being a consistent predictor. FCS presence (OR 2.94, 95% CI 1.06-8.14; p = 0.038) and GTR (92.1% vs 77.3%, p = 0.016) were independently correlated with superior early and long-term FN results, respectively. Subgroup analysis revealed that FCS presence predicted better short- and long-term FN outcomes only in retrosigmoid cases, whereas heterogeneous enhancement was correlated with worse results in translabyrinthine cases. Serviceable hearing was preserved, when attempted, in 41.7% of patients; higher trends were seen with FCS size ≥ 3 mm, nonheterogeneous tumors, retrosigmoid cases, and earlier surgeon experience. The learning curve stage was not correlated with overall FN outcomes. CONCLUSIONS:A multidisciplinary surgical team can achieve favorable FN and hearing results in neuromonitoring-guided VS surgery, regardless of the surgeon's learning curve stage. FCS presence was a positive prognosticator of FN outcomes in retrosigmoid cases, while the translabyrinthine approach offered inferior results in cystic tumors. Larger case-volume studies are warranted to reliably evaluate middle cranial fossa cases and hearing outcome predictors.
OBJECTIVE:Cushing's disease (CD) is a severe endocrine disorder that remains difficult to treat. The first-line treatment for confirmed CD is selective pituitary adenoma resection. Postoperative hormonal remission may not be achieved, though, despite surgical intervention. Effective postoperative monitoring of the hormonal response in CD remains challenging. METHODS:A multicenter observational retrospective cohort study was conducted including 162 patients with CD who underwent endoscopic endonasal resection from January 2007 to September 2021. Three institutions from the United States and Europe participated: University of Southern California, University of Naples Federico II, and Medical University of Vienna. Clinical information including age, sex, preoperative serum and urinary free cortisol levels, imaging findings, histopathological examination including immunohistochemical results, postoperative endocrinological results, and time to follow-up were reported. RESULTS:Data were reviewed for 162 patients with biochemically confirmed CD undergoing surgery via an endoscopic endonasal approach. Morning cortisol < 2 µg/dL or < 5 µg/dL during the first 3 postoperative days (PODs) was associated with lower odds of recurrence (for < 2 µg/dL: OR 0.08, 95% CI 0.004-0.38 [p = 0.01]; for < 5 µg/dL: OR 0.25, 95% CI 0.09-0.61 [p = 0.003]). However, when comparing the two cutoff values (< 2 µg/dL and < 5 µg/dL), a trend toward increased risk was observed in patients with higher cortisol levels, although the difference was not statistically significant (OR 2.1, 95% CI 0.59-7.81; p = 0.25). CONCLUSIONS:Early postoperative hypocortisolemia with cortisol levels < 5 µg/dL within the first 3 days after surgery is a strong predictor of long-term remission. A cortisol level < 2 µg/dL on POD 1 was also significantly associated with a lower risk of recurrence, corresponding to a 91.8% recurrence-free survival rate with a mean follow-up of 29.8 ± 28.7 months.
OBJECTIVE:Parkinson's disease (PD) is characterized by both motor and nonmotor symptoms, including cognitive impairment. Neuronal loss in the nucleus basalis of Meynert (NBM) plays a role in the presentation of cognitive impairment in PD. The implantation of peripheral nerve tissue (PNT) might provide neuroprotective and regenerative capabilities and has shown promising open-label outcomes. The aim of this study was to investigate the safety, feasibility, and clinical outcomes of implanting PNT to the NBM in patients with PD. METHODS:Seven participants with PD underwent bilateral deep brain stimulation (DBS) electrode implantation to the globus pallidus internus plus unilateral PNT regenerating sural nerve graft to the NBM. Participants were monitored at 6-month intervals postoperatively. Clinical outcome measures included neuropsychological, motor, nonmotor, and quality of life ratings. RESULTS:All participants completed the 6- and 12-month visits and 5 completed the 24-month visit. There were no serious adverse events related to the study intervention. Neuropsychological performance results were similar to those of patients who underwent DBS standard-of-care procedures without graft implantation. Motor and quality of life ratings were slightly worse, with slight improvements in overall nonmotor scores. CONCLUSIONS:Unilateral implantation of PNT to the NBM was determined as a safe and feasible procedure such that it did not substantially increase the risk for cognitive decline and dementia beyond rates typically observed in late-stage PD. The current study targeted the NBM, an area not associated with motor symptoms, and the mild progression of motor and quality of life ratings suggest that PNT support might have target-specific clinical effects. These findings support the need for further research in this area, including larger studies that use appropriate control groups.
OBJECTIVE:Early repair of transected peripheral nerves is advocated to maximize recovery; however, clinical delays are common. Conditioning, a well-known method accelerating nerve regeneration, has never been used in a postinjury setting. The authors tested whether postinjury, prerepair conditioning electrical stimulation (CES) can biologically bridge the interval to surgery so that a delayed repair (DR) yields outcomes comparable to, or greater than, an immediate repair (IR). METHODS:Adult male Sprague Dawley rats were randomized to 4 cohorts: 1) CES-cut-IR (CES 1 week before nerve cut + IR), 2) cut-IR (cut and IR, no CES), 3) cut-DR (cut, DR 10 days later, no CES), and 4) cut-CES-DR (nerve cut, CES on postinjury day 3, DR 7 days later). Outcomes evaluated included axon extension 14 days postrepair, sensory recovery (von Frey thresholds, intraepidermal nerve fiber density), and motor recovery (toe-spread and ladder-rung performance, compound muscle action potential [CMAP] amplitudes, gastrocnemius mass, and innervated neuromuscular junctions [NMJs]). RESULTS:For all outcomes evaluated, postinjury CES significantly improved regeneration and reinnervation when compared with no-CES controls. Furthermore, this cohort also had outcomes comparable to the IR cohort that had been treated with CES. Axon extension was comparable between the cut-CES-DR (12.5 ± 0.9 mm) and the CES-cut-IR positive-control cohort (12.1 ± 0.7 mm), and significantly longer than cut-IR (6.9 ± 0.6 mm, p < 0.001) and cut-DR (7.2 ± 0.5 mm, p < 0.001) controls. Between 7 and 8 weeks postrepair, sensory recovery assessed with von Frey filaments identified sensory recovery in the cut-CES-DR cohort comparable to the CES-cut-IR positive control, and significantly greater than the cut-IR and cut-DR controls (both p < 0.001); these results were confirmed on intraepidermal nerve fiber density counts. At 8 weeks, motor function was improved in the cut-CES-DR cohort (toe spread 73.2% contralateral; ladder score 5.0 ± 0.1) versus cut-IR and cut-DR cohorts (approximately 43%; scores 3.6 and 3.3, respectively; p < 0.001), approximating CES-cut-IR cohort. This was confirmed by CMAP amplitudes, gastrocnemius muscle mass, and quantification of innervation NMJs, which demonstrated similar trends. CONCLUSIONS:A single, brief CES session delivered after injury and before repair enables delayed neurorrhaphy to recapitulate IR biology, significantly improving regeneration and reinnervation over delayed or IR without CES. This is the first demonstration of a conditioning-like effect in the clinically relevant situation of an already transected nerve. These results position postinjury CES as a practical bridge to surgery for timing-constrained nerve repairs.
OBJECTIVE:The objective of this study was to investigate the impact of 3D 1H-MR spectroscopy (MRS)-guided metabolic boundary resection (MBR) on the extent of resection (EOR), surgical safety, and prognosis in glioblastoma. METHODS:A retrospective analysis was performed on clinical data from patients with IDH-wildtype glioblastoma who underwent resection at the authors' hospital. Patients were divided into two groups based on surgical methods: the traditional boundary resection (TBR) group (neuronavigation + contrast-enhancing [CE] boundary resection) and the MBR group (3D 1H-MRS combined with neuronavigation + MBR). Demographic, perioperative, and follow-up data were collected and compared between the two groups. Cox proportional hazards regression and Kaplan-Meier survival analysis were used to evaluate the effects of various clinical and treatment-related factors on patient survival. RESULTS:The MBR group included 41 patients (mean age 54.17 ± 12.04 years, 65.85% male) with a mean tumor volume of 58.07 ± 20.63 cm3. The TBR group included 30 patients (mean age 56.86 ± 9.78 years, 63.33% male) with a mean tumor volume of 52.51 ± 24.06 cm3. There were no statistically significant differences between the two groups in tumor laterality, location, volume, and length of hospital stay. In the TBR group, 10 patients achieved supra-total resection (SpTR), 13 achieved gross-total resection (GTR), and 7 achieved subtotal resection (STR). In the MBR group, 25 patients achieved SpTR, 10 achieved GTR, and 6 achieved STR. The rate of SpTR was significantly higher in the MBR group compared to the TBR group (p = 0.021). Postoperative neurological deficits occurred in 1 patient (2.4%) in the MBR group (transient) and 2 patients (6.7%) in the TBR group (1 permanent). No significant difference in complication rates was observed (p = 0.369). Kaplan-Meier survival analysis and log-rank tests demonstrated that the MBR group had significantly longer progression-free survival (PFS) and overall survival (OS) compared to the TBR group (p < 0.001). Multivariable Cox proportional hazards regression analysis identified EOR and surgical methods as independent prognostic factors. CONCLUSIONS:Three-dimensional 1H-MRS combined with a neuronavigation system is used to guide glioblastoma resection along the metabolic boundary during surgery, which can lead to a more complete resection of the glioblastoma and improve the PFS and OS of patients. Compared to CE boundary resection, MBR appears to be a stronger prognostic factor for survival.
