bluuebunny/crossref_metadata_2025 huggingface dataset:
130 Prediction of In-Hospital Mortality After Acute Traumatic Brain Injury managed by Tranexamic Acid: Secondary Exploration of CRASH-3 Trial via Automated Machine Learning
Authors: Haider Ali , Ullah Tauseef , Khan Inayat Ullah , Zehra Saiqa , Khawaja Hashir Fahim , Mehmood Abbas Syed Mohammad , Mohsin Rabia , Khan Ayesha Khalid , Shah Ali Haider
Published: March 2023

INTRODUCTION:

Acute traumatic brain injury (acTBI) has significant morbidity and mortality (M&M) associated with it— increased intracranial pressure (ICP) among the attributed causative mechanisms. Tranexamic acid, therefore, is adopted to decrease ICP and subsequently the acTBI-associated M&M.

METHODS:

The study population comprised 12,743 patients from 175 hospitals in 29 countries experiencing acTBI randomly assigned to receive tranexamic acid or placebo. The current state of the art (SOTA) for automated Machine Learning (aML) was adopted to develop predictive models with the incorporation of the ensemble approach. Logloss and Macro weighted average Area Under the Receiver Operating Curve (mWA-AUROC) assessed the predictive discriminative ability of the developed models.

RESULTS:

An ensemble of Extreme Gradiant Boosting Machine, Light Gradiant Boosting Machine, CatBoost, Random Forest and Neural Network predicted IHM along with the cause of death in acTBI patients randomly assigned to Tranexamic acid management with an mWA-AUROC of 0.94, an accuracy of 85.8% and a logloss of 0.37. Motor and verbal responses along with pupillary reactions were recognized as the most influential predictors for IHM in such patients with maintenance dose of Tranexamic acid imparting moderate to minuscule influence. Boxplot indicates a relative decrease in logloss by adopting the ensemble approach.

CONCLUSIONS:

Our novel approach to developing predictive prognosticative models for acTBI patients managed by Tranexamic acid by exploring automated machine learning is the very first attempt of its nature. Adoption of the current SOTA for aML provides optimal predictions which, when incorporated into the respective management and prognosticative protocols, shall translate into a decrease in the M&M associated with TBI by assisting in risk stratification and complication triaging.
133 Evaluating the Neuroprotectivity of Hypercapnia on Spreading Depolarizations
Authors: Shukla Geet , Parks Ken , Hartings Jed
Published: March 2023

INTRODUCTION:

Spreading depolarizations (SDs) are a class of pathologic electrical activity in the brain characterized by ionic equilibrium disruption and depression of brain activity. SDs are recorded in stroke and traumatic brain injury and are a predictor of secondary damage. We recently found that low end-tidal CO2 (ETCO2) may be associated with a detrimental course of SDs in patients, but it is unknown whether this association is causal.

METHODS:

In mechanically ventilated rats under normoxia (30% O2) assigned to either hypocapnia (ETCO2 25-30 mmHg) or hypercapnia (45-50 mmHg), we triggered SDs via microinjection of 1M KCl for 90 minutes in the cerebral cortex. Additionally, in rats brought to hypoxia (10% O2), we triggered singular SDs under hypocapnia, normocapnia (30-35 mmHg), and hypercapnia. We measured regional cerebral blood flow (rCBF), tissue oxygenation, pH, and SD electrophysiology.

RESULTS:

ETCO2 had no significant effect on SD duration, frequency, delay after stimulus induction, or terminal SD at the time of death. ETCO2 showed a weak negative effect on maximum rCBF, but no effect on duration or integral of rCBF response. In contrast, mean arterial pressure (MAP) showed a strong negative effect on SD duration and delay after stimulus induction but had no effect on frequency. MAP also showed a mild effect on maximum rCBF, as well as the duration and integral of rCBF response.

CONCLUSIONS:

This research showed that ETCO2 does not play a role in determining duration and frequency of spreading depolarizations as well as associated hyperemic response. However, we confirmed prior results that MAP may play a role since relative hypertension was shown to reduce duration of SDs and level of rCBF response.
137 Successful Management of Refractory Craniofacial Pain With Peripheral Nerve Field Stimulation: An International Case Series
Authors: Chavarro Velina S. , Nair Ishiwara , Lieber Bryan , Eshraghi Yashar , Denis Daniel , Olson Sarah
Published: March 2023

INTRODUCTION:

Craniofacial pain syndromes (CPS) encompass various debilitating pain etiologies including trigeminal neuralgia, migraine, cluster headaches, atypical facial pain and post-herpetic neuralgia. Although medical management is initially indicated, most patients with CPS eventually require surgical intervention.

METHODS:

This is a retrospective chart review of adults with refractory CPS who underwent PNFS. Implantation areas included the greater occipital nerve and CNV branches. Outcomes include pain severity measured with Barrow Pain Scale (BPS), functional status pre- and post-operatively, complications secondary to PNFS, and time to re-intervention.

RESULTS:

Seventeen patients underwent PNFS implantation for: atypical TN (48%), migraine (18%), post-herpetic neuralgia (12%), other CPS (17%). Baseline BPS pain score was 5/5 for all patients. At 2 weeks post-PNFS 88% of patients (N = 16) reported BPS score of 1/5. At 1-month post-PNFS 77% of patients (N = 17) had BPS score 2/5 or less; at 6 months follow-up, 77% of patients (N = 14) had BPS score 2/5 or less; and at 12-month follow-up, 63% of patients (N = 11) reported BPS score 2/5 or less. Patients with good outcomes had no further pain-related hospital admissions. The most sustained results were achieved amongst patients with post-herpetic neuralgia. Complications included infection in 2 patients, and refractory pain in 3 patients requiring re-intervention at 10 months post-PNFS on average.

CONCLUSIONS:

This case series demonstrates the utility of PNFS for CPS refractory to traditional medical and surgical management. All patients reported significant pain relief with improvement of function early in the post-operative period. Different etiologies of CPS and PNFS technology may partially explain the variability in long-term outcomes. PNFS technology is continuously optimizing pulse settings and technical characteristics and may be an adequate intervention for refractory CPS.
138 Open Dorsal Root Ganglion Lead Placement After Percutaneous Trialing: A Case Series
Authors: Elhamdani Shahed , Esplin Nathan , Tomycz Nestor Denys
Published: March 2023

INTRODUCTION:

Dorsal root ganglion (DRG) stimulation is a newer mode of neurostimulation for neuropathic pain in which individual electrodes are placed over the dorsal root ganglion (DRG). Although designed for percutaneous placement, open placement of DRG has been described in small case series and case reports when percutaneous placement failed or was anatomically not considered feasible. This is the largest series of open DRG stimulator placement and the first performed after successful percutaneous trialing.

METHODS:

We present a case series of N = 6 patients who underwent successful DRG stimulator placement via open laminotomy/laminectomy technique after a successful percutaneous DRG stimulator trial performed by a pain management physician.

RESULTS:

At a median 7.3 months status post implant, all patients continue to report significant relief of pain with their stimulator. There were no serious adverse events. Mean fluoroscopy time/case was 49.7 seconds. Technical nuances of open DRG stimulator placement will be discussed.

CONCLUSIONS:

This is the largest series of open DRG stimulator placement that has been reported. We have observed good patient pain relief and no serious adverse events. Although more invasive, potential advantages of open DRG stimulator placement include direct anchoring technique and lower radiation exposure times for patients and staff. Open DRG stimulator technique via laminectomy/laminotomy may also improve adoption of DRG stimulation by spinal surgeons who are familiar with exposing the DRG with open technique.
139 Durable Pain Relief With 10 kHz Spinal Cord Stimulation for Patients With Refractory Back Pain Who are not Surgical Candidates
Authors: Patel Naresh P. , Kapural Leonardo , Jameson Jessica , Johnson Curtis , Calodney Aaron K. , Kosek Peter , Pilitsis Julie G. , Bendel Markus A. , Petersen Erika A. , Wu Chengyuan , Cherry Taissa , Lad Nandan P. , Yu Cong , Sayed Dawood , Goree Johnathan , Lyons Mark K. , Sack Andrew , Bruce Diana , Rubenstein Frances , Province-Azalde Rose , Caraway David
Published: March 2023

INTRODUCTION:

A large multicenter RCT was undertaken to provide high level evidence of the clinical effectiveness of 10kHz SCS over conventional medical management (CMM) for the treatment of nonsurgical refractory back pain (NSRBP), and the 12-month results were recently published (Kapural et al, 2022).

METHODS:

Patients were enrolled if ineligible for surgery based on surgical consultation. Subjects were randomized 1:1 to either 10kHz SCS in addition to CMM or CMM alone. Both groups had the option of crossing over at 6 months if satisfactory pain relief was not achieved. In addition, all subjects had the option of consenting to a study extension to 24-months. We present pain relief reported on the visual analog scale (VAS), Oswestry Disability Index (ODI), and quality-of-life (EQ-5D-5L) at 18 months.

RESULTS:

There were 159 patients randomized to either CMM alone (n = 75) or to 10kHz SCS in addition to CMM (n=83), with similar baseline characteristics. None of the 69 implanted patients in the 10 kHz SCS arm chose to crossover to CMM arm, while 74.7% (56/75) in the CMM arm crossed over, resulting in 125 total implanted patients. A total of 5/125 (4%) explants occurred during 18-month follow-up, two due to dissatisfaction with therapy and three to infection (two replaced). At 18 months the following outcomes were achieved: durable pain relief (mean 71%, 95%CI 66-76%), 74% of patients with clinically significant disability improvement with 40% moving from severe/moderate disability to minimal disability, and significant improvement in all dimensions of the EQ-5D-5L.

CONCLUSIONS:

This large, multicenter study demonstrates that the addition of 10kHz SCS to CMM results in profound and durable improvements in pain relief, function, and quality-of-life in these NSRBP patients who have been deemed not surgical candidates and exhausted all available appropriate nonoperative medical management.
144 Sports Participation and Sports-Related Neurologic Injuries in Pediatric Patients With Chiari I Malformation
Authors: Wieland Clare , Holste Katherine , Garton Hugh , Muraszko Karin M. , Maher Cormac O.
Published: March 2023

INTRODUCTION:

Currently, there is no consensus recommendation regarding the safety of sports participation for pediatric patients with Chiari I malformation (CM-I).

METHODS:

A prospectively administered survey was given to 744 pediatric neurosurgery clinic patients at the University of Michigan between December 2010 and December 2021. Data were recorded on demographic information, imaging characteristics, treatment, sports participation, and presence of sports-related neurologic injury. Patients with incomplete survey data were called. Two hundred and seven patients completed at least 1 subsequent survey and were prospectively followed for a mean of 1.56 years. A season was defined as 3 months of sports play.

RESULTS:

Of the 744 patients with completed surveys, 462 patients participated in sports. Patients who participated in sports were more likely to be older at presentation (p < 0.001) and have rounded cerebellar tonsil morphology (p < 0.001). A cumulative total of 6,854.67 seasons of sports were played (5,918.67 prior to CM-I decompression (CMD) and 936 after). There were 84 sports-related concussions among 55 patients; 79 prior to CMD and 5 after CMD. The concussion rate was 12.25 per 1,000 seasons of all sports, 9.16 per 1,000 seasons of limited-contact sports and 13.76 per 1,000 of contact sports. The concussion rate after CMD was 5.34 per 1,000 seasons of all sports, 9.19 per 1,000 seasons of limited-contact sports and 7.09 per 1,000 seasons of contact sports. There were no reports of long-lasting neurologic issues post-concussion or of permanent spinal cord injury.

CONCLUSIONS:

There were no permanent or catastrophic sports-associated neurologic injuries reported in this study. The concussion rate in CM-1 patients before and after CMD were low and therefore sports participation in this population should not be counseled against.
145 Incorporating Intraoperative Mechanomyography to Peripheral Nerve Decompression Surgery
Authors: Taghlabi Khaled , Guerrero Jaime , Cruz-Garza Jesus , Javeed Saad , Dibble Christopher , Ray Wilson Zachary , Faraji Amir H.
Published: March 2023

INTRODUCTION:

Considerable progress has been made in the development of novel intraoperative nerve monitoring technologies. Recent studies demonstrated the high sensitivity of mechanomyography (MMG) in detecting nerve function as compared to traditional electromyographic recording. MMG reflects the mechanical vibrations of single motor units detected via accelerometer sensors and is therefore indicative of underlying axonal integrity.

METHODS:

A total of 20 consecutive patients undergoing decompression procedures for ulnar nerve (8 patients) or common peroneal nerve (12 patients) neuropathies were included. Four patients did not have MMG signals elicited: 1 ulnar and 3 common peroneal nerve patients. Intraoperatively, the nerves were stimulated via MMG ball tip electrode probe starting at 0.1 mA threshold and increasing by 0.1 mA increments until target muscle activity was noted. The lowest threshold current required to elicit a muscle response was recorded prior to decompression and following proximal and distal decompression.

RESULTS:

Of the patients, 80% (16/20) had MMG signals detected and recorded. The mean pre-decompression stimulus threshold was 1.59 ± 0.77 mA. Following surgical decompression, a statistically significant improvement in mean MMG stimulus threshold was noted (0.47 mA ± 0.13, p < 0.0001). The average stimulus threshold change for the common peroneal nerve patients was -0.80 mA (p = 0.001), and -1.48 mA (p = 0.002) for ulnar nerve patients. Post-operatively, all patients endorsed symptomatic improvement with no complications.

CONCLUSIONS:

MMG is an established technique that may provide objective intraoperative guidance in determining the extent of surgical nerve decompression. Lower stimulus thresholds likely represent increased sparing of axonal tissue, which may correlate with improved functional recovery. Future work should focus on validating normative values of MMG stimulus thresholds in various nerves and establishing clinical associations with functional outcomes.
149 Quantitative Performance Assessment of a Wirelessly Powered Vagus Nerve Stimulator in a Porcine Model
Authors: Habibagahi Iman , Omidbeigi Mahmoud , Hadaya Joseph , Lyu Hongming , Jang Jaeeun , Ardell Jeff , Bari Ausaf A. , Babakhani Aydin
Published: March 2023

INTRODUCTION:

Electrophysiological stimulation has been widely used in the management of various disorders, including neurological and cardiac disorders. The dependence on an implantable pulse generator (IPG) increases the risk of surgical complications, patient discomfort, and need for IPG replacement surgery in stimulation methods. Wireless and batteryless stimulators offer important capabilities such reduced need for reoperation, and shorter surgical time compared to their wired counterparts. However, stable quantitative functionality assessment of wireless systems is an essential requirement for their practical usage.

METHODS:

In vivo studies were performed in three anesthetized male pigs. Conventional wired stimulation using bipolar electrodes and a wireless stimulator using the circular wireless receiver (ø 13 mm, 483 mg) with cuff electrodes were implanted around the right Vagus nerve of all animals. Stimulation was performed at varying frequencies (1–20 Hz), and pulse widths (0.1–1 ms) using both systems. Heart rate, left ventricle pressure, and EKG were monitored during VNS. A paired t-test was used to compare physiological responses to different VNS systems.

RESULTS:

A total of 84 stimulations by the wireless device and 36 stimulations by the conventional system were performed. 72% of wireless device stimulations and 75% of the conventional VNS stimulations led to significant heart rate reduction (P < 0.05, paired t-test). There was no significant difference between conventional and wireless systems when comparing physiological markers in response to different pulse widths and stimulation frequencies.

CONCLUSIONS:

This study quantitatively compared functionality of a novel wireless and batteryless VNS system to a conventional VNS, and can serve as a basis for future wirelessly powered implants in the field of neurosurgery to assess functionality and perform close loop stimulation using physiological markers.
150 Genetic Markers of Peripheral Nerve Tumors: Results From the UCSF500 Cancer Gene Panel
Authors: Vargas Enrique , Haddad Alexander F. , Vasudevan Harish , Jacques Line G. , Mummaneni Praveen V.
Published: March 2023

INTRODUCTION:

The purpose of the UCSF 500 test is to identify genetic mutations in the DNA of a patient’s cancer. The UCSF 500 test results also provide information on genetic changes that are inherited and increase the risk of developing cancer for a patient or a patient’s family. We report an institutional experience of UCSF500 results from peripheral nerve tumor samples.

METHODS:

The UCSF 500 Cancer Gene Test uses capture-based next-generation sequencing to target and analyze the coding regions (exons) of 529 cancer genes, as well as select introns of 47 genes. This test can be ordered on solid tumors, hematopoietic malignancies, or lesional tissue specimens. A retrospective analysis of patients with schwannoma, malignant peripheral nerve sheath tumors (MPNST), neurofibroma, and other types of peripheral nerve tumors was performed.

RESULTS:

178 samples from 163 patients with peripheral nerve tumors undergoing genetic testing met inclusion criteria. The top 5 mutated genes and their frequency for Neuroblastoma includes PIK3C2G (1.0), IGF1R (0.2), NOTCH2 (0.2), CIC (0.2), ATR (0.2). The 5 genes with the highest frequency copy number alteration (CNA) include SOX9, SRSF2, PRKAR1A, PRKCA, PPM1D. Schwannoma: NF2 (0.58), LZTR1 (0.21), MSH2 (0.14), FAT3 (.13), SMARCB1 (0.1). The top 5 CNA genes were all deletions on chromosome 22. MPNST: TYK2 (1.0), MRE11 (1.0), NF1 (0.65), SUZ12 (0.33), TP53 (0.32). Neurofibroma: TNFAIP3 (1.0), ADGRA2 (1.0), FLT4 (1.0), NF1 (0.61), PRKCH (0.11). Other: TERT (0.39), DDR1 (0.25), KMT2C (0.25), FAT1 (0.15), NRG1 (0.13).

CONCLUSIONS:

We describe an institutional experience with UCSF500 genetic test results on all peripheral nerve tumors sent for analysis from 2015 to 2022. Using these data to guide the development of understudied genes of interest could lead to increased understanding of the genetic mechanism of these tumors.
151 Intracranial Magnetic Resonance Guided Laser Interstitial Thermal Therapy for Epilepsy: A Single Institution’s Experience of 226 Cases
Authors: Philbrick Brandon , Blanpain Lou T. , Gross Robert E. , Willie Jon Timothy
Published: March 2023

INTRODUCTION:

Magnetic resonance guided laser interstitial thermal therapy (MRg-LITT) is a minimally invasive alternative to open surgical resection for epilepsy. Patient and technical factors associated with outcomes remain unclear.

METHODS:

We performed a retrospective review of consecutive patients undergoing MRg-LITT surgery at a single high-volume epilepsy center. Medical and surgical history, trajectory number per patient, adverse events, and outcomes up to 24 months were obtained and statistically analyzed.

RESULTS:

203 patients underwent a total of 226 MRg-LITT procedures for epilepsy between 2011-2020. 52% and 55% of patients experienced seizure freedom at 12 and 24 months after ablation, respectively. Overall, patients with lesional epileptogenic foci were more likely to have better seizure control at 12- and 24-months after surgery (p < 0.05). Of cases performed with curative intent, patients with mesial temporal sclerosis (MTS) were most likely to maintain long-term seizure freedom. Ablations performed for disconnection (corpus callosotomy) or palliation of multifocal epilepsy were unlikely to provide complete seizure freedom. 6 cases (2.7%) were complicated by intra- or post-operative hemorrhage. 3 patients (1.5%) experienced persistent post-operative complaints including cranial nerve palsy and headaches. The odds of complication (minor or major vs none) were multiplied by 1.43 for each additional trajectory (95% CI [1.16, 1.76]), and by 1.04 for each additional 1cm3 of volume ablated (95% CI [1.008, 1.076]).

CONCLUSIONS:

MRg-LITT, a safe and effective approach to distinct epilepsy types, appears most persistently beneficial for lesional epilepsy, particularly MTS. Although serious complications were infrequent, adverse events were statistically correlated with multiple stereotaxic trajectories and larger ablation volumes. Our results provide additional guidance for patient counseling and surgical planning.
152 Caudate and Dorsolateral Prefrontal Cortex Beta Bursts During Working Memory Encoding Correlate with Memory Impairment in Parkinson’s Disease
Authors: Qian Helen , Paulo Danika Lea , Subramanian Deeptha , Dhima Kaltra , Bick Sarah KB
Published: March 2023

INTRODUCTION:

Cognitive dysfunction is a common nonmotor symptom of Parkinson’s disease (PD), with memory impairment being a primary cause of disability. Decreased dopamine in PD elevates beta power in cortico-striato-thalamo-cortico (CSTC) motor circuits and is the basis of closed-loop deep brain stimulation (DBS) strategies. Analogous dysfunction of parallel CSTC cognitive circuitry including caudate and dorsolateral prefrontal cortex (DLPFC) may mediate PD cognitive impairment and be a neuromodulation target for cognitive symptoms. We have previously shown caudate and DLPFC beta power contributes to working memory updating, and suppression of prefrontal cortex beta bursts during working memory encoding has been linked with improved performance. However, how PD affects beta bursting in relation to memory function remains unknown.

METHODS:

Fourteen PD patients undergoing awake DBS surgery with electrode trajectories traversing the caudate, DLPFC, or both participated in this study. Subjects completed a 2-back working memory task where they identified whether a presented word matched the word presented two trials prior. Bursts were defined as epochs where power exceeded a Z-score of two for at least three oscillatory cycles. We correlated change in caudate and DLPFC beta burst rates during working memory encoding with subjects’ composite memory scores, which were calculated from preoperative neuropsychological assessments.

RESULTS:

Caudate and DLPFC beta burst rates decreased significantly during working memory encoding for correct trials. In both structures, change in beta burst rate was significantly correlated with subjects’ composite memory scores, with greater decreases in beta bursting corresponding with better memory function.

CONCLUSIONS:

Beta bursts are suppressed in caudate and DLPFC during working memory encoding. Reduced beta burst suppression during encoding correlated with greater memory impairment in PD patients, indicating that altered caudate and DLPFC beta bursting dynamics may contribute to PD memory impairment.
154 Comparison of Chronic and Intraoperative LFP and ECoG Recordings in Humans With Parkinson’s Disease
Authors: Caldwell David , Olaru Maria , de Hemptinne Coralie , Starr Philip A.
Published: March 2023

INTRODUCTION:

Advances in implantable neurotechnologies have enabled chronic invasive long-term recordings of field potentials from depth leads or paddle-type electrocorticography (ECoG) leads. The relationship between these long-term recordings and those obtained acutely in the operating room has not been studied.

METHODS:

Human subjects (n=6) with movement disorders (Parkinson’s disease, dystonia) were permanently implanted with quadripolar DBS leads, and quadripolar ECoG leads over primary motor and sensory cortices, attached to a Medtronic Summit RC+S investigational device in the chest. Recordings were acquired intraoperatively using a NeuroOmega (Alpha Omega, Inc) recording system customized for research use. RC+S recordings were acquired between 1 and 345 days post implantation. The same processing pipeline was applied to both data sets, and average power spectra in canonical frequency bands (delta, theta, alpha, beta, gamma) were compared using rank sum tests within each subject.

RESULTS:

Power spectra show similar power law scaling phenomena between intraoperative and chronic recordings. Disease specific frequency band characteristics such as beta peaks could be seen in both chronic and intraoperative recordings, however, within subjects these were not always consistently seen.

CONCLUSIONS:

We present within-patient comparisons of signal characteristics (power spectra) of intraoperative recordings from a research grade recording system, with wirelessly streamed data from a chronic implantable device, using the same brain leads. Power spectra have similar characteristics between the intraoperative and long term recordings, however, there are distinct differences between the intraoperative and longer term clinic recordings, reinforcing the utility of tracking neural signals over time after the effects of lead insertion on the motor circuit have diminished.
156 Major Depression is Linked to Increased Information Flow From the Orbitofrontal Cortex
Authors: Myers John , Xiao Jiayang , Metzger Brian , Adkinson Joshua , Allawala Anusha , Pirtle Victoria , Mathura Raissa , Anand Adrish , Gadot Ron , Najera Ricardo Andres , Rey Hernan Gonzalo , Shofty Ben , Provenza Nicole , Goodman Wayne , Mathew Sanjay , Pouratian Nader , Bijanki Kelly R. , Sheth Sameer A.
Published: March 2023

INTRODUCTION:

Major depression is associated with widespread dysfunction throughout the limbic system and neocortical regions such as the orbitofrontal cortex (OFC) and the dorsolateral prefrontal cortex (dlPFC) (4–7). The brain regions comprising the limbic system, including the amygdala, ventral striatum, and anterior cingulate cortex (ACC), show altered connectivity in MDD patients (5, 7). As part of an ongoing NIH-funded trial of DBS for depression, we implanted 3 patients with both DBS leads and stereo-EEG (sEEG) electrodes to measure neural oscillations in the dlPFC, OFC, and ACC.

METHODS:

Three depression patients were implanted with sEEG electrodes in areas including OFC, dlPFC, and ACC. We frequently measured depression severity throughout a 9-day inpatient monitoring period using a validated adaptive severity scale (8). We measured directed connectivity using multivariate vector autoregressive models that measure information flow between the right dlPFC, OFC, and ACC during resting state). Then we examined the relationship between depression severity and GC within the delta band (1-3 Hz).

RESULTS:

Information flow within the delta band was positively correlated with depression severity in each patient. Each showed distinct patterns of pathophysiological connectivity. Across all patients, directed connectivity from the OFC to the ACC predicted depression severity (p < 0.05).

CONCLUSIONS:

Information flow within the prefrontal cortex correlates closely with depression severity. Increased OFC -> ACC connectivity may relate to increased self-appraisals of mood and diminished control of emotional state during depressive episodes.
160 The Neurosurgical Anatomy of Deficits in Speech Production
Authors: Andrews John P. , Cahn Nathan , Speidel Benjamin , Chung Jason , Levy Deborah , Wilson Stephen , Berger Mitchel S. , Chang Edward
Published: March 2023

INTRODUCTION:

Why do similar neurosurgical lesions cause a range of deficits in speech production? We investigated Broca’s aphasia as a disorder of fluency and apraxia of speech (AOS) as a disorder of articulatory coordination to dissociate the anatomy and lesional etiology of these syndromes.

METHODS:

Patients were prospectively tested with a standardized speech paradigm. Resections were outlined into 3D regions of interest and transformed into a common brainspace (MNI brain). Recordings of speech were retrospectively review by speech language experts to assess apraxia of speech. A voxel-based lesion-mapping (VLSM) algorithm was used to associate resection areas with acute postoperative aphasia or apraxia of speech. Averages of white-matter tracts were overlaid onto MNI reconstructions for analyses of white-matter tract involvement. Pre-operative diffusion tensor imaging reconstructions were created using peri-lesional regions of interest for seeds to investigate perilesional white matter tracts in these cohorts.

RESULTS:

Of 289 patients with left sided craniotomies and prospective language evaluation, 19 had Broca’s aphasia. 255 of these patients had recordings available for expert review, of whom 28 had apraxia of speech. VLSM analysis found Broca’s aphasia and fluency deficits were not associated with classic anatomic Broca’s area (pars opercularis and triangularis). Rather, they were associated with ventral sensorimotor cortex (SMC) and supramarginal gyrus (P < 0.001). Apraxia of speech was associated the most ventral aspects of SMC (P < 0.001). SLF III reconstructions terminated in the areas associated with Broca’s aphasia and fluency deficits, but had more limited overlap with the VLSM regions associated with apraxia of speech.

CONCLUSIONS:

Lesions leading to AOS and Broca’s aphasia after neurosurgical resection do not correlate with Broca's area. Rather, they cluster in ventral sensorimotor cortex. Subcortical white-matter tract injury may explain disparate non-fluent aphasia subtypes in patients with anatomically similar lesions.
161 Single-Cell RNA-seq Highlights Immune-Driven Gender Differences in Glioblastoma
Authors: Wang Elaina , Young Jacob , Chen Jia-Shu , Aghi Manish Kumar
Published: March 2023

INTRODUCTION:

Glioblastoma (GBM) is the most common primary malignant brain tumor and has a 1.6-fold higher incidence and shorter survival in men versus women. Gene expression differences may contribute to gender-specific differences.

METHODS:

Single cell RNA-sequencing (scRNA-seq) was conducted on 19,642 cells from primary IDH-wild type GBM patients of both sexes (n = 11 total, 5 men and 6 women). A two-sample t-test was conducted on average age between sexes. Kaplan-Meier curves were used to evaluate survival between sexes. Bulk RNA-sequencing data was accessed via The Cancer Genome Atlas GBM dataset. Functional enrichment analyses were conducted on both scRNA and bulk RNA-seq data to determine relevant pathways from upregulated genes and visualized as gene concept networks via R.

RESULTS:

There was no difference in age (63.8 versus 53.8 years in men and women respectively) and survival (24 versus 26 months in men and women respectively). scRNA-seq functional enrichment analysis revealed myeloid cell upregulation in men and increased expression of angiogenesis genes such as ADM in women. There was no difference in T cell gene expression between sexes. Bulk RNA-seq analysis of 90 men and 50 women revealed marked elevation of immunoglobulin genes in men and innate genes such as M1 marker NOS2 in women.

CONCLUSIONS:

Innate myeloid and adaptive humoral components are highly upregulated in men with GBM compared to women, with no differences seen in T cell expression between sexes. This may contribute to higher incidences and shorter survival in men versus women, which should be accounted for in clinical trial evaluation.
168 Elevated Intracranial Pressure is Associated With Memory Dysfunction in Intraventricular Hemorrhage Animal Model
Authors: Peterson Catherine , Puglisi Chloe , Hawk Cameron , Waldau Ben
Published: March 2023

INTRODUCTION:

Survivors of nontraumatic intraventricular hemorrhage are often left with memory impairment, however, underlying mechanisms of this dysfunction remain to be elucidated.

METHODS:

The experimental design included two groups of Sprague Dawley rats (n=30): intraventricular hemorrhage (control) and intraventricular hemorrhage with sustained high intracranial pressures (experimental). The autologous intraventricular blood injection model was used. In the experimental group the intracranial pressure was artificially elevated. Ten days following surgery, each rat underwent Morris water maze. T test was used with a p value of < 0.05 considered statistically significant.

RESULTS:

The average maximum intracranial pressure in the experimental group was 75.6 ± 17.5 mmHg compared to 66.5 ± 17.3 mmHg in the control group (p = 0.260). The experimental group experienced elevated intracranial pressure for two hours following induction of intraventricular hemorrhage, whereas the intracranial pressure normalized within minutes in the control group. The mean cerebral perfusion pressure tended to be lower in the experimental group (20 ± 25.6 mmHg) compared to the control group (30 ± 19.4 mmHg) (p = 0.302). In Morris water maze, the experimental group needed more time to reach the platform (37.3 ± 21.8 seconds) compared to the control group (19.7 ± 14.3 seconds) (p = 0.041). The experimental group also spent less time in 5% and 10% target quadrants, 2.4 ± 1.8 and 5.7 ± 3.9 seconds, respectively (p = 0.004) compared to the control group, 5.3 ± 2.2 and 10 ± 3 seconds, respectively (p < 0.001).

CONCLUSIONS:

Animals who have prolonged elevated intracranial pressures following intraventricular hemorrhage perform poorly in spatial memory and learning. The authors suggest that a rise in intracranial pressure might be the driver for activating pathways responsible for subsequent memory dysfunction.
171 Neurosurgical Utilization, Charges, and Reimbursement Following the Affordable Care Act: Trends from 2011 to 2019
Authors: Hersh Andrew , Dedrickson Tara , Gong Jung Ho , Jimenez Adrian , Materi Joshua , Veeravagu Anand , Ratliff John K. , Azad Tej D.
Published: March 2023

INTRODUCTION:

An estimated fifty million Americans receive Medicare healthcare coverage, a number expected to increase with an aging population. Despite rising costs, prior studies have established a downward trend in Medicare reimbursement rates adjusted for inflation for commonly billed surgical procedures. However, it is unclear if these trends hold true across all neurosurgical procedures.

METHODS:

We review the yearly Physician/Supplier Procedure Summary datasets from the Centers for Medicare and Medicaid Services for all procedures billed by neurosurgeons to Medicare Part B between 2011 and 2019. Procedural coding was categorized into cranial, spine, vascular, peripheral nerve, and radiosurgery cases. Weighted averages for charges and reimbursements adjusted for inflation were calculated each year. The ratio of the weighted mean reimbursement to weighted mean charge was calculated as the reimbursement-to-charge ratio (RCR), representing the proportion of charges reimbursed by Medicare.

RESULTS:

Overall enrollment-adjusted utilization of neurosurgical procedures decreased by 12%, with utilization in the inpatient setting decreasing by 24%. However, we identified a large increase in procedures at ambulatory surgery centers (639%) and in the outpatient setting (80%). Over the study period, inflation-adjusted, weighted mean charges decreased by 4.0% while reimbursement decreased by 4.6%, resulting in a decrease in the RCR of 0.6%. Procedure groups that saw increases in reimbursement included anterior and posterior cervical spine surgery, cranial functional and epilepsy procedures, cranial pain procedures, and endovascular procedures. Ambulatory surgery centers saw the greatest increase in charges and reimbursements.

CONCLUSIONS:

Overall reimbursement declined over the study period; however, significant variations emerged across procedural categories. We further find a significant shift in utilization and reimbursement for neurosurgical procedures outside of inpatient care settings.
174 Magnitude and Origins of Gender Differences in Medicare Payments to Neurosurgeons
Authors: Oshinowo Temitope Oladoyin , Rallo Michael Stephen , Chambless Lola Blackwell
Published: March 2023

INTRODUCTION:

Gender pay disparities have been described across numerous specialties but have been relatively unexplored in neurosurgery.

METHODS:

We analyzed public data summarizing services provided to Medicare beneficiaries from 2013-2019. Practice metrics were compared between male and female neurosurgeons via Students’ T-test, Wilcoxon Rank-Sum, multiple linear regression.

RESULTS:

Women accounted for 8.3% of the 5,846 neurosurgeons serving the Medicare population. Females were reimbursed 41.8% ($59,163.20) less compared to their male colleagues (p < 0.001). Additionally, females billed for fewer services (288 vs. 474, p < 0.001), beneficiaries treated (128 vs. 193, p < 0.01), and unique codes (38.0 vs. 50.0, p < 0.001). However, the disparity persisted even when controlling for differences in years of practice, number of beneficiaries, and total services ($25,444.76, p < 0.001). There was no difference in geographic practice cost indices. The average payment-per-service was $78.15 (95%-CI, $73.14-$83.17, p < 0.001) less than that of males. This was influenced, in part, by women submitting for fewer services within the top quartile of payment (6.26% vs. 11.21%, p < 0.001). However, even when matching procedures by code, females were reimbursed $177.80 (95%-CI, $153.28-$202.31) less than males (p < 0.001).

CONCLUSIONS:

Female neurosurgeons are reimbursed 18% less when controlling for metrics of practice volume including number of services and beneficiaries treated. Importantly, the disparity exists even for individual procedures, which may represent more limited use of enhancement modifiers. Identifying origins of this disparity will aid in designing interventions that promote more equitable compensation for the work of female neurosurgeons. It is important to note that this database describes a primarily adult patient population and, therefore, discrepancies in reimbursement for pediatric neurosurgery, a field in which women represent a larger proportion, cannot be extrapolated from this study.
176 Use of Computed Assisted Neuronavigation During Spine Fusions and Long-term Health Care Utilization: An Exact Matched Analysis of National Administrative Database
Authors: Sharma Mayur , Ugiliweneza Beatrice , Boakye Maxwell , Drazin Doniel
Published: March 2023

INTRODUCTION:

Computer assisted neuronavigation (CAN) during spine fusions has increasing being utilized in the United States. The impact of CAN on long-term health care utilization is not well defined.

METHODS:

MarketScan database were queried using the ICD-9/10 and CPT 4th edition, from 2003 to 2019. We included patients ≥ 18 of age who underwent spine fusions with at least 2 years follow-up. Outcomes were repeat fusions or new fusions, length of stay (LOS), discharge disposition, hospital re-admissions, outpatient services, and medication refills for up to 24 months following the index procedure.

RESULTS:

Of 183,620 patients who underwent spine fusions during the study years, 5046 (2.75%) were identified to have CAN used for the fusions. Exact matching was successful for 4861/5046 (96%) in the CAN group. CAN had no effect on LOS, home discharge, or complications at index hospitalization and 30-days post discharge. However, CAN was associated with a $7667 difference in median payments ($60501 vs $52834, p < .0001). CAN was associated with lower rates of repeat fusions at 6-months (3% vs. 4%), 12 months (2% vs. 3%) and 24 months (5% vs. 6%) following the index procedure, p < 0.05. Patients who underwent CAN had lower payments at 6 months ($5186 vs $5527, p: 0.0159), 12 months ($10267 vs $11262, p: 0.0207) and 24 months ($21453 vs $24355, p: 0.0021).

CONCLUSIONS:

CAN is increasing being used for spine fusions primarily for thoraco-lumbar procedures. No difference in complications, discharge disposition and LOS were noted across the cohorts at index hospitalization, with higher index payments with CAN use. CAN was associated with lower rates of repeat fusions and corresponding health care utilization for up-to 24 months following the index procedures compared to non-CAN cohort.
177 International Authorship Trends in Academic Neurosurgery and Effect of Double-Blind Review
Authors: Chalif Eric , Yue John K. , Chillakuru Yeshwant , Badani Aarav , Aghi Manish Kumar
Published: March 2023

INTRODUCTION:

There is a lack of data on international publication rates and whether reviewer biases exist that may affect diversity of authorship.

METHODS:

Articles published within Neurosurgery, Journal of Neurosurgery (JNS), and World Neurosurgery (WNS) were collected from 2000-2019. Country affiliation data was assigned and analyzed with respect to journal, year of publication, neurosurgical subspeciality, and relative impact.

RESULTS:

Across 23,325 articles, lead authorship consisted of United States (42.9%, N = 10,005), Japan (9.9%, N = 2,305), China (9.3%, N = 2,167), Germany (5.1%, N = 1,187), South Korea (3.3%, N = 773), Italy (3.3%, N = 773), Canada (3.3%, N = 769), and other nations (22.9%, N = 5,346). Rates of publications did not differ across United States, Asian countries, South/Latin American countries, or African countries pre- and post-initiation of double-blind review in Neurosurgery (p > 0.05). Annual percentage of publications showed highest relative decrease for the United States (-0.48% per year, r2 = 0.194) and increase for China (0.87% per year, r2 = 0.761). WNS published fewer articles from the United States compared to Neurosurgery or JNS (Mean difference [MD] -20.6%, p < 0.001), and more articles from Asian (MD +23.5%, p < 0.001), Latin/South American (MD +1.4%, p < 0.001), and African countries (MD +0.8%, p < 0.001). Unbiased co-authorship clustering by country demonstrated that certain countries were more likely to publish together based on geopolitical characteristics.

CONCLUSIONS:

There is a higher relative contribution to neurosurgery publications from authors in the United States compared to other countries. This effect is not due to potential biases in single-blind review, as evidenced by a natural experiment comparing authorship rates at Neurosurgery pre- and post-initiation of double-blind review in 2011. Additional research is needed to determine whether other biases contribute to differences in publication rates across countries.
181 Costs of Surgery in Adult Spinal Deformity: Do Higher Cost Surgeries Lead to Better Outcomes?
Authors: Passias Peter G. , Joujon-Roche Rachel , Williamson Tyler K. , Tretiakov Peter S. , Imbo Bailey , Krol Oscar , Lebovic Jordan , Diebo Bassel G. , Vira Shaleen
Published: March 2023

INTRODUCTION:

With increased focus on delivering cost effective healthcare, interventions associated with high resource utilization, such as adult spinal deformity (ASD) surgery, have received greater scrutiny.

METHODS:

A retrospective analysis of a single-center ASD database. ASD patients ≥18 years with baseline (BL) and 2-year (2Y) data were included. Surgical costs were calculated based on 2021 average Medicare reimbursement by CPT code. Costs of complications and reoperations were intentionally excluded. Patients were ranked into tertiles by surgical cost. The tertile with the highest surgical costs (HC) and lowest surgical costs (LC) were propensity score matched (PSM’d) to account for differences in baseline age and deformity. Multivariable logistic regressions assessed odds of achieving outcomes of interest in PSM’d groups.

RESULTS:

421 patients met inclusion (139 LC; 127 HC). After PSM, 102 patients remained in each cost group with an average reimbursement of LC: $11,279 vs. HC: $29,274. PSM’d groups had similar demographics and baseline deformity (all p >.05). Compared to LC patients, HC had higher odds of meeting SCB in SRS-22-Total (OR: 2.461, [1.321, 4.586], p = .005) and higher odds of meeting SCB in NRS Back (OR:1.961, [1.032, 3.723], p = .040). With respect to deformity, HC patients were more likely to have “0” Schwab modifier at 2Y in SVA (OR: 5.736, [2.798, 11.761], p<.001), PI-LL (OR: 2.239, [1.100, 4.559], p = .026), and PT (OR: 2.456, [1.335, 4.518], p = .004).

CONCLUSIONS:

While patient presentation impacts surgical planning and costs, we sought to control for such variations to assess association between surgical costs and outcomes. Although higher cost did not guarantee an ideal outcome, high cost patients generally experienced superior patient reported outcomes and realignment at 2-years. Thus, isolating cost reduction as a public health priority may compromise outcomes in ASD patients.
183 Proposed Classification System of Radiographic Bone Changes After Cervical Disc Replacement
Authors: Khachatryan Armen , Phillips Frank M. , Lanman Todd Hopkins , Andersson Gunnar B. J. , Jacobs Joshua , Kurtz Steven , Pratt Stuart
Published: March 2023

INTRODUCTION:

Cervical Disc Replacement (CDR) is an increasingly utilized procedure to address cervical degenerative conditions, as an alternative to discectomy and fusion, for the purpose of preserving natural segmental motion.

METHODS:

Using serial radiographs from patients, a panel of experts assembled for the purpose of creating a classification system to aid in reproducibly and consistently identifying boney changes and assessing CDR device radiographic appearance. Subdividing the superior and inferior vertebral bodies into 3 equal sections, observed bone loss such as endplate rounding, cystic erosion adjacent to the endplate, and cystic erosion not adjacent to the endplate, is recorded. Determining if bone loss is progressive and estimating severity of bone loss (measured by the percentage of end plate involved) is recorded. Additional relevant boney changes and device observations include radiolucent lines, heterotopic ossification, loss of core implant height, and presence of device migration, subsidence, and olisthesis.

RESULTS:

Serial radiographs from 26 patients implanted with a variety of CDR products were assessed by 6 investigators including clinicians and scientists experienced in CDR or appendicular skeleton joint replacement. After several iterations, a classification system emerged that had improved concordance among the participating investigators. Next steps include assessing reliability with a broad group of clinicians, using serial radiographs from a significant number of patients, to confirm the proposed classification scheme.

CONCLUSIONS:

A standardized nomenclature for boney changes following CDR will facilitate accurate and reproducible scientific communications regarding the clinical outcomes of this procedure. The novel system proposed demonstrated good concordance among experienced investigators in this field and represents an important advancement.