The Association Between Task Complexity and Cortical Language Mapping Accuracy.

BACKGROUND AND OBJECTIVES: Direct cortical stimulation (DCS) mapping enables the identification of functional language regions within and around gliomas before tumor resection. Intraoperative mapping is required because glioma-infiltrated cortex engages in synchronous activity during task performance in a manner similar to normal-appearing cortex but has decreased ability to encode information for complex tasks. It is unknown whether task complexity influenced DCS mapping results. We aim to understand correlations between audiovisual picture naming (PN) task complexity and DCS error rate. We also asked what functional and oncological factors might be associated with higher rates of erroneous responses. METHODS: We retrospectively reviewed intraoperative PN and word reading (WR) task performance during awake DCS language mapping for resection of dominant hemisphere World Health Organization grade 2 to 4 gliomas. The complexity of word tested in PN/WR tasks, patient characteristics, and tumor characteristics were compared between correct and incorrect trials. RESULTS: Between 2017 and 2021, 74 patients met inclusion criteria. At median 18.6 months of follow-up, 73.0% were alive and 52.7% remained recurrence-free. A total of 2643 PN and 978 WR trials were analyzed. A greater number of syllables in PN was associated with a higher DCS error rate (P = .001). Multivariate logistic regression found that each additional syllable in PN tasks independently increased odds of error by 2.40 (P < .001). Older age was also an independent correlate of higher error rate (P < .043). World Health Organization grade did not correlate with error rate (P = .866). More severe language impairment before surgery correlated with worse performance on more complex intraoperative tasks (P < .001). A higher error rate on PN testing did not correlate with lower extent of glioma resection (P = .949). CONCLUSION: Word complexity, quantified by the number of syllables, is associated with higher error rates for intraoperative PN tasks but does not affect extent of resection.

What is the effect of preoperative depression on outcomes after minimally invasive surgery for adult spinal deformity? A prospective cohort analysis.

OBJECTIVE: Depression has been implicated with worse immediate postoperative outcomes in adult spinal deformity (ASD) correction, yet the specific impact of depression on those patients undergoing minimally invasive surgery (MIS) requires further clarity. This study aimed to evaluate the role of depression in the recovery of patients with ASD after undergoing MIS. METHODS: Patients who underwent MIS for ASD with a minimum postoperative follow-up of 1 year were included from a prospectively collected, multicenter registry. Two cohorts of patients were identified that consisted of either those affirming or denying depression on preoperative assessment. The patient-reported outcome measures (PROMs) compared included scores on the Oswestry Disability Index (ODI), numeric rating scale (NRS) for back and leg pain, Scoliosis Research Society Outcomes Questionnaire (SRS-22), SF-36 physical component summary, SF-36 mental component summary (MCS), EQ-5D, and EQ-5D visual analog scale. RESULTS: Twenty-seven of 147 (18.4%) patients screened positive for preoperative depression. The nondepressed cohort had an average of 4.83 levels fused, and the depressed cohort had 5.56 levels fused per patient (p = 0.267). At 1-year follow-up, 10 patients still reported depression, representing a 63% decrease. Postoperatively, both cohorts demonstrated improvement in their PROMs; however, at 1-year follow-up, those without depression had statistically better outcomes based on the EQ-5D, MCS, and SRS-22 scores (p < 0.05). Patients with depression continued to experience higher NRS leg scores at 1-year follow-up (3.63 vs 2.22, p = 0.018). After controlling for covariates, the authors found that depression significantly impacted only 1-year follow-up MCS scores (ß = 8.490, p < 0.05). CONCLUSIONS: Depressed and nondepressed patients reported similar improvements after MIS surgery, except MCS scores were more likely to improve in nondepressed patients.

Multilevel Laminoplasty for CSM: Is C3 Laminectomy Better Than C3 Laminoplasty at the Superior Vertebra?

INTRODUCTION: In a multilevel cervical laminoplasty operation for patients with cervical spondylotic myelopathy (CSM), a partial or complete C3 laminectomy may be performed at the upper level instead of a C3 plated laminoplasty. It is unknown whether C3 technique above the laminoplasty affects loss of cervical lordosis or range of motion. METHODS: Patients undergoing multilevel laminoplasty of the cervical spine (C3-C6/C7) at a single institution were retrospectively reviewed. Patients were divided into two cohorts based on surgical technique at C3: C3-C6/C7 plated laminoplasty ("C3 laminoplasty only", N = 61), C3 partial or complete laminectomy, plus C4-C6/C7 plated laminoplasty (N = 39). All patients had at least 1-year postoperative X-ray treatment. RESULTS: Of 100 total patients, C3 laminoplasty and C3 laminectomy were equivalent in all demographic data, except for age (66.4 vs. 59.4 years, p = 0.012). None of the preoperative radiographic parameters differed between the C3 laminoplasty and C3 laminectomy cohorts: cervical lordosis (13.1° vs. 11.1°, p = 0.259), T1 slope (32.9° vs. 29.2°, p = 0.072), T1 slope-cervical lordosis (19.8° vs. 18.6°, p = 0.485), or cervical sagittal vertical axis (3.1 cm vs. 2.7 cm, p = 0.193). None of the postoperative radiographic parameters differed between the C3 laminoplasty and C3 laminectomy cohorts: cervical lordosis (9.4° vs. 11.2°, p = 0.369), T1 slope-cervical lordosis (21.7° vs. 18.1°, p = 0.126), to cervical sagittal vertical axis (3.3 cm vs. 3.6 cm, p = 0.479). In the total cohort, 31% had loss of cervical lordosis >5°. Loss of lordosis reached 5-10° (mild change) in 13% of patients and >10° (moderate change) in 18% of patients. C3 laminoplasty and C3 laminectomy cohorts did not differ with respect to no change (<5°: 65.6% vs. 74.3%, respectively), mild change (5-10°: 14.8% vs. 10.3%), and moderate change (>10°: 19.7% vs. 15.4%) in cervical lordosis, p = 0.644. When controlling for age, ordinal regression showed that surgical technique at C3 did not increase the odds of postoperative loss of cervical lordosis. C3 laminectomy versus C3 laminoplasty did not differ in the postoperative range of motion on cervical flexion-extension X-rays (23.9° vs. 21.7°, p = 0.451, N = 91). CONCLUSION: There was no difference in postoperative loss of cervical lordosis or postoperative range of motion in patients who underwent either C3-C6/C7 plated laminoplasty or C3 laminectomy plus C4-C6/C7 plated laminoplasty.

Safety and comparative efficacy of initiating low-molecular-weight heparin within 24 hours of injury or surgery for venous thromboembolism prophylaxis in patients with spinal cord injury: a prospective TRACK-SCI registry study.

OBJECTIVE: Venous thromboembolism (VTE) following traumatic spinal cord injury (SCI) is a significant clinical concern. This study sought to determine the incidence of VTE and hemorrhagic complications among patients with SCI who received low-molecular-weight heparin (LMWH) within 24 hours of injury or surgery and identify variables that predict VTE using the prospective Transforming Research and Clinical Knowledge in SCI (TRACK-SCI) database. METHODS: The TRACK-SCI database was queried for individuals with traumatic SCI from 2015 to 2022. Primary outcomes of interest included rates of VTE (including deep vein thrombosis [DVT] and pulmonary embolism [PE]) and in-hospital hemorrhagic complications that occurred after LWMH administration. Secondary outcomes included intensive care unit and hospital length of stay, discharge location type, and in-hospital mortality. RESULTS: The study cohort consisted of 162 patients with SCI. Fifteen of the 162 patients withdrew from the study, leading to loss of data for certain variables for these patients. One hundred thirty patients (87.8%) underwent decompression and/or fusion surgery for SCI. DVT occurred in 11 (7.4%) of 148 patients, PE in 9 (6.1%) of 148, and any VTE in 18 (12.2%) of 148 patients. The analysis showed that admission lower-extremity motor score (p = 0.0408), injury at the thoracic level (p = 0.0086), admission American Spinal Injury Association grade (p = 0.0070), and younger age (p = 0.0372) were significantly associated with VTE. There were 3 instances of postoperative spine surgery-related bleeding (2.4%) in the 127 patients who had spine surgery with bleeding complication data available, with one requiring return to surgery (0.8%). Thirteen (8.8%) of 147 patients had a bleeding complication not related to spine surgery. There were 2 gastrointestinal bleeds associated with nasogastric tube placement, 3 cases of postoperative non-spine-related surgery bleeding, and 8 cases of other bleeding complications (5.4%) not related to any surgery. CONCLUSIONS: Initiation of LMWH within 24 hours was associated with a low rate of spine surgery-related bleeding. Bleeding complications unrelated to SCI surgery still occur with LMWH administration. Because neurosurgical intervention is typically the limiting factor in initializing chemical DVT prophylaxis, many of these bleeding complications would have likely occurred regardless of the protocol.

Superior Hypophyseal Artery Intraoperative Indocyanine Green Angiogram as a Predictor of Postoperative Visual Function After Endoscopic Endonasal Surgery.

BACKGROUND AND OBJECTIVES: To date, there are no tools to intraoperatively predict postoperative visual function after endoscopic endonasal surgery (EES) for suprasellar lesions. The objective of this study was to retrospectively evaluate the utility of indocyanine green (ICG) angiography as an intraoperative tool to measure optic chiasm perfusion and determine its relationship with postoperative visual function. METHODS: Videos of patients undergoing EES for resection of suprasellar lesions were reviewed, where 5 mg of ICG was diluted in 10 mL of saline and administered. Time between luminescence of the anterior cerebral artery and the superior hypophyseal artery branches supplying the optic chiasm was noted, and the percentage of optic chiasm vessels that luminesced was recorded. Postoperative examinations and imaging studies were used to assess visual function. Patients with and without new deficits were compared with examination of trends in ICG findings. RESULTS: A total of 7 trials were reviewed on 6 patients, with no complications occurring from ICG administration. Mean time to chiasm peak luminescence was 3.8 seconds, and 81.8% of chiasm vessels luminesced. Patients with stable or improved vision after resection demonstrated over 90% chiasm luminescence in every case, and mean chiasm time in these postresection ICG administrations was 4.0 seconds. One patient experienced new postoperative visual deficits; on review of their ICG administration, 11.5% of chiasm vessels luminesced, and the chiasm itself failed to display robust luminescence after 30 seconds of direct observation. CONCLUSION: This pilot study showed the capability of intraoperative ICG angiography to demonstrate perfusion of the optic chiasm during EES for resection of suprasellar lesions. While larger studies are required, preliminary results suggest chiasm times under 5 seconds and over 90% chiasm vessel illumination may reflect adequate chiasm perfusion, while those with delayed or absent chiasm luminescence may have compromised chiasm perfusion.

Update on Pediatric Mild Traumatic Brain Injury in Rural and Underserved Regions: A Global Perspective.

BACKGROUND: Mild traumatic brain injury (MTBI) causes morbidity and disability worldwide. Pediatric patients are uniquely vulnerable due to developmental and psychosocial factors. Reduced healthcare access in rural/underserved communities impair management and outcome. A knowledge update relevant to current gaps in care is critically needed to develop targeted solutions. METHODS: The National Library of Medicine PubMed database was queried using comprehensive search terms (("mild traumatic brain injury" or "concussion") and ("rural" or "low-income" or "underserved") and ("pediatric" or "child/children")) in the title, abstract, and Medical Subject Headings through December 2022. Fifteen articles on rural/underserved pediatric MTBI/concussion not covered in prior reviews were examined and organized into four topical categories: epidemiology, care practices, socioeconomic factors, and telehealth. RESULTS: Incidences are higher for Individuals in rural regions, minorities, and those aged 0-4 years compared to their counterparts, and are increasing over time. Rural healthcare utilization rates generally exceed urban rates, and favor emergency departments (vs. primary care) for initial injury assessment. Management guidelines require customization to resource-constrained settings for implementation and adoption. Decreased community recognition of the seriousness of injury is a consensus challenge to care provision by clinicians. Low parental education and income were correlated with decreased MTBI knowledge and worse outcome. Telehealth protocols for triage/consultation and rehabilitation were feasible in improving care delivery to rural and remote settings. CONCLUSIONS: Pediatric MTBI/concussion patients in rural/underserved regions experience increased risks of injury, geographic and financial healthcare barriers, and poorer outcomes. Globally, under-reporting of injury has hindered epidemiological understanding. Ongoing MTBI education should be implemented for rural caregivers, schools, and low-income populations to improve community awareness. Telehealth can improve care delivery across acuity settings, and warrants judicious inclusion in triage and treatment protocols.

Risk Factors for Significant Postoperative Hemorrhage After Pituitary Neuroendocrine Tumor Resection: A Case-Control Study of 1066 Surgeries.

BACKGROUND: Postoperative hemorrhage is a rare but potentially serious complication after pituitary surgery. The risk factors for this complication are mostly unknown, and further knowledge would help guide postoperative management. OBJECTIVE: To investigate the perioperative risks and clinical presentation of significant postoperative hemorrhage (SPH) after endonasal surgery for pituitary neuroendocrine tumors. METHODS: A population of 1066 patients undergoing endonasal (microscopic and endoscopic) surgery for pituitary neuroendocrine tumor resection at a high-volume academic center was reviewed. SPH cases were defined as postoperative hematoma evident on imaging requiring return to the operating room for evacuation. Patient and tumor characteristics were analyzed with uni- and multivariable logistic regression, and postoperative courses were descriptively examined. RESULTS: Ten patients were found to have SPH. On univariable analysis, these cases were significantly more likely to present with apoplexy ( P = .004), have larger tumors ( P < .001), and lower gross total resection rates ( P = .019). A multivariate regression analysis showed that tumor size (odds ratio 1.94, P = .008) and apoplexy at presentation (odds ratio 6.00, P = .018) were significantly associated with higher odds of SPH. The most common symptoms for patients with SPH were vision deficits and headache, and the median time for symptom onset was 1 day after surgery. CONCLUSION: Larger tumor size and presentation with apoplexy were associated with clinically significant postoperative hemorrhage. Patients presenting with pituitary apoplexy are more likely to experience a significant postoperative hemorrhage and should be carefully monitored for headache and vision changes in the days after surgery.

Leveraging machine learning to ascertain the implications of preoperative body mass index on surgical outcomes for 282 patients with preoperative obesity and lumbar spondylolisthesis in the Quality Outcomes Database.

OBJECTIVE: Prior studies have revealed that a body mass index (BMI) ≥ 30 is associated with worse outcomes following surgical intervention in grade 1 lumbar spondylolisthesis. Using a machine learning approach, this study aimed to leverage the prospective Quality Outcomes Database (QOD) to identify a BMI threshold for patients undergoing surgical intervention for grade 1 lumbar spondylolisthesis and thus reliably identify optimal surgical candidates among obese patients. METHODS: Patients with grade 1 lumbar spondylolisthesis and preoperative BMI ≥ 30 from the prospectively collected QOD lumbar spondylolisthesis module were included in this study. A 12-month composite outcome was generated by performing principal components analysis and k-means clustering on four validated measures of surgical outcomes in patients with spondylolisthesis. Random forests were generated to determine the most important preoperative patient characteristics in predicting the composite outcome. Recursive partitioning was used to extract a BMI threshold associated with optimal outcomes. RESULTS: The average BMI was 35.7, with 282 (46.4%) of the 608 patients from the QOD data set having a BMI ≥ 30. Principal components analysis revealed that the first principal component accounted for 99.2% of the variance in the four outcome measures. Two clusters were identified corresponding to patients with suboptimal outcomes (severe back pain, increased disability, impaired quality of life, and low satisfaction) and to those with optimal outcomes. Recursive partitioning established a BMI threshold of 37.5 after pruning via cross-validation. CONCLUSIONS: In this multicenter study, the authors found that a BMI ≤ 37.5 was associated with improved patient outcomes following surgical intervention. These findings may help augment predictive analytics to deliver precision medicine and improve prehabilitation strategies.

Paraparesis caused by intradural thoracic spinal granuloma secondary to organizing hematoma: illustrative case.

BACKGROUND: Spinal granulomas form from infectious or noninfectious inflammatory processes and are rarely present intradurally. Intradural granulomas secondary to hematoma are unreported in the literature and present diagnostic and management challenges. OBSERVATIONS: A 70-year-old man receiving aspirin presented with encephalopathy, subacute malaise, and right lower extremity weakness and was diagnosed with polysubstance withdrawal and refractory hypertension requiring extended treatment. Seven days after admission, he reported increased bilateral lower extremity (BLE) weakness. Magnetic resonance imaging showed T2-3 and T7-8 masses abutting the pia, with spinal cord compression at T2-3. He was transferred to the authors' institution, and work-up showed no vascular shunting or malignancy. He underwent T2-3 laminectomies for biopsy/resection. A firm, xanthochromic mass was resected en bloc. Pathology showed organizing hematoma without infection, vascular malformation, or malignancy. Subsequent coagulopathy work-up was unremarkable. His BLE strength significantly improved, and he declined resection of the inferior mass. He completed physical therapy and was cleared for placement in a skilled nursing facility. LESSONS: Spinal granulomas can mimic vascular lesions and malignancy. The authors present the first report of paraparesis caused by intradural granuloma secondary to organizing hematoma, preceded by severe refractory hypertension. Tissue diagnosis is critical, and resection is curative. These findings can inform the vigilant clinician for expeditious treatment.

Involvement of White Matter Language Tracts in Glioma: Clinical Implications, Operative Management, and Functional Recovery After Injury.

To achieve optimal survival and quality of life outcomes in patients with glioma, the extent of tumor resection must be maximized without causing injury to eloquent structures. Preservation of language function is of particular importance to patients and requires careful mapping to reveal the locations of cortical language hubs and their structural and functional connections. Within this language network, accurate mapping of eloquent white matter tracts is critical, given the high risk of permanent neurological impairment if they are injured during surgery. In this review, we start by describing the clinical implications of gliomas involving white matter language tracts. Next, we highlight the advantages and limitations of methods commonly used to identify these tracts during surgery including structural imaging techniques, functional imaging, non-invasive stimulation, and finally, awake craniotomy. We provide a rationale for combining these complementary techniques as part of a multimodal mapping paradigm to optimize postoperative language outcomes. Next, we review local and long-range adaptations that take place as the language network undergoes remodeling after tumor growth and surgical resection. We discuss the probable cellular mechanisms underlying this plasticity with emphasis on the white matter, which until recently was thought to have a limited role in adults. Finally, we provide an overview of emerging developments in targeting the glioma-neuronal network interface to achieve better disease control and promote recovery after injury.

Comparison of Outcomes following Primary and Repeat Resection of Craniopharyngioma.

Introduction The management of recurrent craniopharyngioma is complex with limited data to guide decision-making. Some reports suggest reoperation should be avoided due to an increased complication profile, while others have demonstrated that safe reoperation can be performed. For other types of skull base lesions, maximal safe resection followed by adjuvant therapy has replaced radical gross total resection due to the favorable morbidity profiles. Methods Seventy-one patients underwent resection over a 9-year period for craniopharyngioma and were retrospectively reviewed. Patients were separated into primary resection and reoperation cohorts and stratified by surgical approach (endonasal vs. cranial) and survival analyses were performed based on cohort and surgical approach. Results Fifty patients underwent primary resection, while 21 underwent reoperation for recurrence. Fifty endonasal transsphenoidal surgeries and 21 craniotomies were performed. Surgical approaches were similarly distributed across cohorts. Subtotal resection was achieved in 83% of all cases. There were no differences in extent of resection, visual outcomes, subsequent neuroendocrine function, and complications across cohorts and surgical approaches. The median time to recurrence was 87 months overall, and there were no differences by cohort and approach. The 5-year survival rate was 81.1% after reoperation versus 93.2% after primary resection. Conclusion Compared with primary resection, reoperation for craniopharyngioma recurrence is associated with similar functional and survival outcomes in light of individualized surgical approaches. Maximal safe resection followed by adjuvant radiotherapy for residual tumor likely preserves vision and endocrine function without sacrificing overall patient survival.

Decision tree-based machine learning analysis of intraoperative vasopressor use to optimize neurological improvement in acute spinal cord injury.

OBJECTIVE: Previous work has shown that maintaining mean arterial pressures (MAPs) between 76 and 104 mm Hg intraoperatively is associated with improved neurological function at discharge in patients with acute spinal cord injury (SCI). However, whether temporary fluctuations in MAPs outside of this range can be tolerated without impairment of recovery is unknown. This retrospective study builds on previous work by implementing machine learning to derive clinically actionable thresholds for intraoperative MAP management guided by neurological outcomes. METHODS: Seventy-four surgically treated patients were retrospectively analyzed as part of a longitudinal study assessing outcomes following SCI. Each patient underwent intraoperative hemodynamic monitoring with recordings at 5-minute intervals for a cumulative 28,594 minutes, resulting in 5718 unique data points for each parameter. The type of vasopressor used, dose, drug-related complications, average intraoperative MAP, and time spent in an extreme MAP range (< 76 mm Hg or > 104 mm Hg) were collected. Outcomes were evaluated by measuring the change in American Spinal Injury Association Impairment Scale (AIS) grade over the course of acute hospitalization. Features most predictive of an improvement in AIS grade were determined statistically by generating random forests with 10,000 iterations. Recursive partitioning was used to establish clinically intuitive thresholds for the top features. RESULTS: At discharge, a significant improvement in AIS grade was noted by an average of 0.71 levels (p = 0.002). The hemodynamic parameters most important in predicting improvement were the amount of time intraoperative MAPs were in extreme ranges and the average intraoperative MAP. Patients with average intraoperative MAPs between 80 and 96 mm Hg throughout surgery had improved AIS grades at discharge. All patients with average intraoperative MAP > 96.3 mm Hg had no improvement. A threshold of 93 minutes spent in an extreme MAP range was identified after which the chance of neurological improvement significantly declined. Finally, the use of dopamine as compared to norepinephrine was associated with higher rates of significant cardiovascular complications (50% vs 25%, p < 0.001). CONCLUSIONS: An average intraoperative MAP value between 80 and 96 mm Hg was associated with improved outcome, corroborating previous results and supporting the clinical verifiability of the model. Additionally, an accumulated time of 93 minutes or longer outside of the MAP range of 76-104 mm Hg is associated with worse neurological function at discharge among patients undergoing emergency surgical intervention for acute SCI.

Neuro-Oncology Patients as Human Research Subjects: Ethical Considerations for Cognitive and Behavioral Testing for Research Purposes.

Language, cognition, and behavioral testing have become a fundamental component of standard clinical care for brain cancer patients. Many existing publications have identified and addressed potential ethical issues that are present in the biomedical setting mostly centering around the enrollment of vulnerable populations for therapeutic clinical trials. Well-established guides and publications have served as useful tools for clinicians; however, little has been published for researchers who share the same stage but administer tests and collect valuable data solely for non-therapeutic investigational purposes derived from voluntary patient participation. Obtaining informed consent and administering language, cognition, and behavioral tasks for the sole purpose of research involving cancer patients that exhibit motor speech difficulties and cognitive impairments has its own hardships. Researchers may encounter patients who experience emotional responses during tasks that challenge their existing impairments. Patients may have difficulty differentiating between clinical testing and research testing due to similarity of task design and their physician's dual role as a principal investigator in the study. It is important for researchers to practice the proposed methods emphasized in this article to maintain the overall well-being of patients while simultaneously fulfilling the purpose of the study in a research setting.

Association of Neurological Impairment on the Relative Benefit of Maximal Extent of Resection in Chemoradiation-Treated Newly Diagnosed Isocitrate Dehydrogenase Wild-Type Glioblastoma.

BACKGROUND: Increases in the extent of resection of both contrast-enhanced (CE) and non-contrast-enhanced (NCE) tissue are associated with substantial survival benefits in patients with isocitrate dehydrogenase wild-type glioblastoma. The fact, however, remains that these lesions exist within the framework of complex neural circuitry subserving cognition, movement, and behavior, all of which affect the ultimate survival outcome. The prognostic significance of the interplay between CE and NCE cytoreduction and neurological morbidity is poorly understood. OBJECTIVE: To identify a clinically homogenous population of 228 patients with newly diagnosed isocitrate dehydrogenase wild-type glioblastoma, all of whom underwent maximal safe resection of CE and NCE tissue and adjuvant chemoradiation. We then set out to delineate the competing interactions between resection of CE and NCE tissue and postoperative neurological impairment with respect to overall survival. METHODS: Nonparametric multivariate models of survival were generated via recursive partitioning to provide a clinically intuitive framework for the prognostication and surgical management of such patients. RESULTS: We demonstrated that the presence of a new postoperative neurological impairment was the key factor in predicting survival outcomes across the entire cohort. Patients older than 60 yr who suffered from at least one new impairment had the worst survival outcome regardless of extent of resection (median of 11.6 mo), whereas those who did not develop a new impairment had the best outcome (median of 28.4 mo) so long as all CE tissue was resected. CONCLUSION: Our data provide novel evidence for management strategies that prioritize safe and complete resection of CE tissue.

Resection of supplementary motor area gliomas: revisiting supplementary motor syndrome and the role of the frontal aslant tract.

OBJECTIVE: The supplementary motor area (SMA) is an eloquent region that is frequently a site for glioma, or the region is included in the resection trajectory to deeper lesions. Although the clinical relevance of SMA syndrome has been well described, it is still difficult to predict who will become symptomatic. The object of this study was to define which patients with SMA gliomas would go on to develop a postoperative SMA syndrome. METHODS: The University of California, San Francisco, tumor registry was searched for patients who, between 2010 and 2019, had undergone resection for newly diagnosed supratentorial diffuse glioma (WHO grades II-IV) performed by the senior author and who had at least 3 months of follow-up. Pre- and postoperative MRI studies were reviewed to confirm the tumor was located in the SMA region, and the extent of SMA resection was determined by volumetric assessment. Patient, tumor, and outcome data were collected retrospectively from documents available in the electronic medical record. Tumors were registered to a standard brain atlas to create a frequency heatmap of tumor volumes and resection cavities. RESULTS: During the study period, 56 patients (64.3% male, 35.7% female) underwent resection of a newly diagnosed glioma in the SMA region. Postoperatively, 60.7% developed an SMA syndrome. Although the volume of tumor within the SMA region did not correlate with the development of SMA syndrome, patients with the syndrome had larger resection cavities in the SMA region (25.4% vs 14.2% SMA resection, p = 0.039). The size of the resection cavity in the SMA region did not correlate with the severity of the SMA syndrome. Patients who developed the syndrome had cavities that were located more posteriorly in the SMA region and in the cingulate gyrus. When the frontal aslant tract (FAT) was preserved, 50% of patients developed the SMA syndrome postoperatively, whereas 100% of the patients with disruption of the FAT during surgery developed the SMA syndrome (p = 0.06). Patients with SMA syndrome had longer lengths of stay (5.6 vs 4.1 days, p = 0.027) and were more likely to be discharged to a rehabilitation facility (41.9% vs 0%, p < 0.001). There was no difference in overall survival for newly diagnosed glioblastoma patients with SMA syndrome compared to those without SMA syndrome (1.6 vs 3.0 years, p = 0.33). CONCLUSIONS: For patients with SMA glioma, more extensive resections and resections involving the posterior SMA region and posterior cingulate gyrus increased the likelihood of a postoperative SMA syndrome. Although SMA syndrome occurred in all cases in which the FAT was resected, FAT preservation does not reliably avoid SMA syndrome postoperatively.

Functional alterations in cortical processing of speech in glioma-infiltrated cortex.

Recent developments in the biology of malignant gliomas have demonstrated that glioma cells interact with neurons through both paracrine signaling and electrochemical synapses. Glioma-neuron interactions consequently modulate the excitability of local neuronal circuits, and it is unclear the extent to which glioma-infiltrated cortex can meaningfully participate in neural computations. For example, gliomas may result in a local disorganization of activity that impedes the transient synchronization of neural oscillations. Alternatively, glioma-infiltrated cortex may retain the ability to engage in synchronized activity in a manner similar to normal-appearing cortex but exhibit other altered spatiotemporal patterns of activity with subsequent impact on cognitive processing. Here, we use subdural electrocorticography to sample both normal-appearing and glioma-infiltrated cortex during speech. We find that glioma-infiltrated cortex engages in synchronous activity during task performance in a manner similar to normal-appearing cortex but recruits a diffuse spatial network. On a temporal scale, we show that signals from glioma-infiltrated cortex have decreased entropy, which may affect its ability to encode information during nuanced tasks such as production of monosyllabic versus polysyllabic words. Furthermore, we show that temporal decoding strategies for distinguishing monosyllabic from polysyllabic words were feasible for signals arising from normal-appearing cortex but not from glioma-infiltrated cortex. These findings inform our understanding of cognitive processing in chronic disease states and have implications for neuromodulation and prosthetics in patients with malignant gliomas.

Oncology and Spinal Neurosurgeons Performing Resections of Intramedullary Ependymomas Compared with Single Neurosurgeons: A 13-Year Experience at a Single Institution.

OBJECTIVE: Resection of intramedullary spinal ependymomas carries great risk of postoperative neurological deficits. The objective of this study was to describe our experience using co-neurosurgeon teams to address intramedullary ependymomas to determine if the use of 2 experienced attending neurosurgeons with expertise in both neurosurgical oncology and spine pathology can improve outcomes for intramedullary ependymoma resections. METHODS: We retrospectively compared surgical and disease control outcomes in intramedullary ependymoma cases performed by co-neurosurgeon (one neurosurgical oncologist and one neurosurgeon trained in spinal surgery) and single-neurosurgeon teams over a 13-year period at a single institution. RESULTS: Co-neurosurgeons performed resections in 34 (47.9%) patients, and a single neurosurgeon performed resections in 37 (52.1%) patients. There were no significant differences in the frequency of gross total resection in the co-neurosurgeon versus single-neurosurgeon group (85.7% vs. 78.4%, P = 0.45). Posterior spinal fusion was more common in the co-neurosurgeon group (35.3%) compared with the single-neurosurgeon group (8.1%) (P = 0.01). Two (5.9%) patients in the co-neurosurgeon group and 5 (13.5%) patients in the single-neurosurgeon group had complications requiring surgical revision (P = 0.28). Recurrence rates were similar in both groups (5.9% vs. 10.8%, P = 0.50). At last follow-up, 76% of patients who presented with mild or no deficits remained functionally independent. CONCLUSIONS: Resection of intramedullary ependymomas by co-neurosurgeon teams resulted in similar rates of gross total resection, postoperative complications, and recurrence compared with surgeries performed by a single neurosurgeon. Functional neurological outcomes were not impacted by co-neurosurgeons performing ependymoma resections.

Balancing task sensitivity with reliability for multimodal language assessments.

OBJECTIVE: Intraoperative tasks for awake language mapping are typically selected based on the language tracts that will likely be encountered during tumor resection. However, diminished attention and arousal secondary to perioperative sedatives may reduce a task's usefulness for identifying eloquent cortex. For instance, accuracy in performing select language tasks may be high preoperatively but decline in the operating room. In the present study, the authors sought to identify language tasks that can be performed with high accuracy in both situational contexts so the neurosurgical team can be confident that speech errors committed during awake language mapping result from direct cortical stimulation to eloquent cortex, rather than from poor performance in general. METHODS: We administered five language tasks to 44 patients: picture naming (PN), text reading (TR), auditory object naming (AN), repetition of 4-syllable words (4SYL), and production of syntactically intact sentences (SYNTAX). Performance was assessed using the 4-point scale of the quick aphasia battery 24 hours preoperatively and intraoperatively. We next determined whether or not accuracy on each task was higher preoperatively than intraoperatively. We also determined whether 1) intraoperative accuracy on a given task predicted intraoperative performance on the other tasks and 2) low preoperative accuracy on a task predicted a decrease in accuracy intraoperatively. RESULTS: Relative to preoperative accuracy, intraoperative accuracy declined on PN (3.90 vs 3.82, p = 0.0001), 4SYL (3.96 vs 3.91, p = 0.0006), and SYNTAX (3.85 vs 3.67, p = 0.0001) but not on TR (3.96 vs 3.94, p = 0.13) or AN (3.70 vs 3.58, p = 0.058). Intraoperative accuracy on PN and AN independently predicted intraoperative accuracy on the remaining language tasks (p < 0.001 and p < 0.01, respectively). Finally, low preoperative accuracy on SYNTAX predicted a decrease in accuracy on this task intraoperatively (R2 = 0.36, p = 0.00002). CONCLUSIONS: While TR lacks sensitivity in identifying language deficits at baseline, accuracy on TR is stable across testing settings. Baseline accuracy on the other four of our five language tasks was not predictive of intraoperative performance, signifying the need to repeat language tests prior to stimulation mapping to confirm reliability.

Convergence of heteromodal lexical retrieval in the lateral prefrontal cortex.

Lexical retrieval requires selecting and retrieving the most appropriate word from the lexicon to express a desired concept. Few studies have probed lexical retrieval with tasks other than picture naming, and when non-picture naming lexical retrieval tasks have been applied, both convergent and divergent results emerged. The presence of a single construct for auditory and visual processes of lexical retrieval would influence cognitive rehabilitation strategies for patients with aphasia. In this study, we perform support vector regression lesion-symptom mapping using a brain tumor model to test the hypothesis that brain regions specifically involved in lexical retrieval from visual and auditory stimuli represent overlapping neural systems. We find that principal components analysis of language tasks revealed multicollinearity between picture naming, auditory naming, and a validated measure of word finding, implying the existence of redundant cognitive constructs. Nonparametric, multivariate lesion-symptom mapping across participants was used to model accuracies on each of the four language tasks. Lesions within overlapping clusters of 8,333 voxels and 21,512 voxels in the left lateral prefrontal cortex (PFC) were predictive of impaired picture naming and auditory naming, respectively. These data indicate a convergence of heteromodal lexical retrieval within the PFC.