bluuebunny/crossref_metadata_2025 huggingface dataset:
483 Partial Treatment as a Risk Factor in Up-Conversion of Type 1 dAVFs
Authors: Walker Erin , Srienc Anja I. , Guniganti Ridhima Rao , Brinjikji Waleed , Chen Ching-Jen , Abecassis Isaac Josh , Levitt Michael Robert , Durnford Andrew , Polifka Adam J. , Derdeyn Colin P. , Samaniego Edgar A. , Kwasnicki Amanda M. , Alaraj Ali , Potgieser Adriaan R.E. , Sur Samir , Tada Yoshiteru , Winkler Ethan A. , Lai Rosalind , Du Rose , Abla Adib Adnan , Satomi Junichiro , Starke Robert M. , Van Dijk Marc C. , Amin-Hanjani Sepideh , Hayakawa Minako , Gross Bradley A. , Fox William C. , Butlers Diederik , Kim Louis J. , Sheehan Jason P. , Lanzino Giuseppe , Osbun Joshua William , Zipfel Gregory J.
Published: March 2023

INTRODUCTION:

Type 1 dural arteriovenous fistulas (dAVFs) lack cortical venous drainage and occasionally necessitate intervention depending on patient symptoms. Up-conversion is the rare transformation of a dAVF to a higher-grade. Causes for up-conversion are unknown. We tested the hypothesis whether partial treatment of type 1 dAVFs increases their likelihood of up-conversion.

METHODS:

We used the multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database to perform a retrospective analysis of all patients with type 1 dAVFs. Propensity score analysis was utilized to determine if partial treatment was an independent risk factor for up-conversion. A regression model identified secondary risks that contributed to up-conversion.

RESULTS:

358 out of 1077 patients within the consortium had type 1 dAVFs. 12% of patients who were partially treated for a type 1 dAVF experienced an up-conversion, while less than 1% of patients who received no treatment experienced up-conversion, and 0% of patients who had a complete treatment of their dAVF experienced up-conversion. Higher proportions of tinnitus, bruits, and intracranial hemorrhage at initial presentation were found in patients who up-converted. The majority of up-converted dAVFs were located in the transverse-sigmoid sinus and all received embolization as part of their treatment.

CONCLUSIONS:

Partial treatment is an independent risk factor for up-conversion when compared to no treatment or complete treatment. In the partial treatment group, hemorrhage at inital presentation and use of embolization as a treament modality are factors that increase risk for up-conversion.
484 Predictors of Outcome Clusters for Anterior Circulation Mechanical Thrombectomy: An Unsupervised Machine Learning Analysis of Prospective Data
Authors: Naik Anant , Catapano Joshua , Hartke Joelle Nicole , Koester Stefan Wolfgang , Winkler Ethan A. , Jadhav Ashutosh , Ducruet Andrew F. , Albuquerque Felipe
Published: March 2023

INTRODUCTION:

Endovascular thrombectomy for select patients with anterior circulation stroke can be lifesaving if done in an appropriate therapeutic window. However, studies have demonstrated that failure of treatment ranges from 30-70%. Early determination of patients that are most likely to benefit from early revascularization is of pivotal importance.

METHODS:

We prospectively collected data from a high-volume stroke center for patients receiving MT for anterior circulation strokes. Outcomes evaluated included final Thrombolysis in Cerebral Infarction (TICI) score, the number of passes, complications from endovascular intervention, discharge NIHSS. Outcomes were clustered using a k-means model after the number of optimal clusters were obtained using a silhouette algorithm. Uniform manifold projections (UMAP) were used to project the four outcomes into a 2-D space. Upon cluster determination, multivariate regression was used to determine predictors of cluster membership. Univariate comparisons leveraged chi-square and t-tests.

RESULTS:

187 consecutive patients were selected for analysis. Included patients had an average age 69.96 (SD – 15.14). Two distinct clusters were obtained, confirmed by the Silhouette model (1B). Cluster 2 was found to be associated with improved outcomes on univariate regression. Multivariate regression was used to identify predictors of cluster membership. ICA occlusion (OR = 7.63 (1.40 – 48.6), p = 0.02). A one-point increase in admission NIHSS was associated with an 11% increase in cluster 2 risk.

CONCLUSIONS:

In this study, we consolidate 4 outcomes using unsupervised machine learning. We found that cluster 2 patients did worse. We also demonstrated that ICA occlusion, Admission NIHSS, and smoking status were significantly associated with cluster 2 membership. Machine learning can be used to identify novel morphological characteristics of specific patient groups.
486 Macroscale Forces Drive Targetable Microscale Fibrotic Mechanosensing in Degenerative Spinal Disease
Authors: Hadzipasic Muhamed , Sten Margaret , Massaad Elie , Kiapour Ali , Nageeb George , Sharif Muneeb , Bradley Joseph , Nielsen Gunnlaugur , Coumans Jean-Valery , Borges Lawrence F. , Shin John H. , Grodzinsky Alan , Nia Hadi , Shankar Ganesh
Published: March 2023

INTRODUCTION:

Mechanical forces are emerging as key drivers of fibrosis. Elucidating this pathophysiology is relevant in degenerative spinal disease (DSD) where mechanical stress on the spine is associated with fibrotic changes in ligament and bone, with resultant compression of the neural elements. Though DSD affects most people as they age and costs $3.6 billion annually, the crucial bridge between macroscale mechanical forces driving pathologic degenerative mechanosensing remains unknown.

METHODS:

Validated lumbo-pelvic finite element models (FEMs) were used to calculate LF macroscale stress; LF was collected from 120 patients undergoing surgery and studied via histology, Western blot and novel Atomic Force Microscopy (AFM) stiffness mapping. A novel device to apply strain to LF was engineered to further investigate the real-time effect of resulting stress on myofibroblast accumulation and transcriptome-level gene expression.

RESULTS:

Spinopelvic FEM predicted LF adjacent to a fused level experiences increased stress during spine flexion. Supporting this model, LF resected adjacent to a fused level was observed to have significant increases in pro-fibrotic myofibroblasts (4.3-fold) and downstream ROCK effectors compared with LF from non-DSD and DSD patients without prior fusion. AFM and mathematical modeling revealed myofibroblasts localize to islands of elevated stiffness and microstress within LF. Through application of strain on LF explants, we observed stress-dependent myofibroblast accumulation (3.66-fold, P < .0002) and blocked this accumulation through ROCK inhibition. Finally, through transcriptomic analysis on human LF, we identify a stress-driven hyperacute transcriptional response and find this response is also altered by ROCK inhibition.

CONCLUSIONS:

These findings implicate stress-driven myofibroblast accumulation as a mechanosensitive pro-fibrotic pathway in DSD. These observations warrant detailed future investigation into ROCK inhibitors as a potentially surgery-sparing adjunct to non-operative therapy in ASD and DSD-mediated spinal stenosis.
488 Prospective Evaluation of Racial Disparities in Surgical Treatment Of Degenerative Spondylolisthesis Using PROMIS Pain Interference And Physical Function Scores
Authors: Massaad Elie , Taylor Mitchell , Shin John H. , Williamson Theresa
Published: March 2023

INTRODUCTION:

Spine surgery for degenerative spondylolisthesis is indicated in patients who remain symptomatic despite a course of nonsurgical therapy. Patient’s report of pain interference and physical function are key indicators for intervention. We know that Black and indigenous patients of color have poorer outcomes in back pain. This study aims to identify trends in intervention for degenerative spondylolisthesis based on race and patient-reported outcomes.

METHODS:

A prospective cohort study of degenerative spondylolisthesis patients seen in Harvard Medical School-affiliated clinics from 2015 to 2022 and who completed the routinely collected PROMIS patient-reported outcome measures (PROMs): Physical Function (PF) and pain Interference (PI). PROMIS scores are standardized to the U.S. population (mean score = 50). Regression analyses were performed to determine factors associated with treatment assignment.

RESULTS:

In this study, 22 374 patients (mean Age, 66.91(14.22); Female, 64%; BIPOC, 3019 (13%)) completed PROMs at baseline. Medicaid coverage was more prevalent among BIPOC (13% vs. 3.1%; P < 0.001) who were less likely to receive an interventional treatment (351/ 3,019 (12%) vs. 3,021 / 19,355 (16%); P < 0.001) despite a significantly higher pain interference score (62.32 (8.37) vs. 61.51 (8.35); P < 0.001). White race was associated with higher odds of receiving surgical treatment than BIPOC after adjusting for age, comorbidities, medical coverage, physical function, and pain interference at baseline (OR = 1.20; 95 CI, 1.15-1.26; P < 0.001).

CONCLUSIONS:

Despite higher pain interference scores, BIPOC patients were less likely to be offered spine surgery for degenerative spondylolisthesis, indicating that race is a predictor of spine surgery after accounting for comorbidities, physical function, and disability at diagnosis.
489 Complications Associated With Single Position Prone Lateral Lumbar Interbody Fusion: A Systematic Review and Meta-Analysis
Authors: Farber Samuel Harrison , Cecchi Bayron Valenzuela , O'Neill Luke , Chapple Kristina , Zhou James , Snyder Laura A. , Turner Jay D. , Uribe Juan S.
Published: March 2023

INTRODUCTION:

Lateral lumbar interbody fusion (LLIF) is a workhorse surgical approach for lumbar arthrodesis. There is now emerging interest in performing single position surgery in which both LLIF and pedicle screw fixation are performed in the prone position. To date, most studies of prone LLIF are of poor quality and without long-term follow up; and as such, the complication profile related to this novel approach is not well known.

METHODS:

A systematic review of the literature and a meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies reporting prone LLIF were assessed for inclusion. Studies not reporting complication rates were excluded.

RESULTS:

A total of 10 studies met inclusion criteria and were included in the analysis. Overall, 286 patients were treated with prone LLIF across these studies with an average of 1.3 (0.2) levels per patient. There were 18 reported intra-operative complications including cage subsidence (3.8%), rupture of the anterior longitudinal ligament (ALL) (2.3%), cage repositioning (2.1%), aborted prone interbody placement (0.82%), and durotomy (0.6%). There were no reported major vascular or peritoneal injuries. A total of 68 post-operative complications occurred. These included thigh/groin sensory symptoms (13.3%), hip flexor weakness (17.8%), wound infection (1.9%), psoas hematoma (1.3%), motor neural injury (1.2%), and revision surgery (3.8%).

CONCLUSIONS:

Single position LLIF in the prone position appears to be a safe surgical approach with a low complication profile. Longer term follow up and prospective studies are needed in order to better characterize long-term complication rates related to this approach.
497 Does Physical Activity Improve Patient Outcomes Following Lumbar Microdiscectomy?
Authors: Yang Amy , Goldschlager Tony , Daly Chris D. , Castle-Kirszbaum Mendel , Rogers Myron A.
Published: March 2023

INTRODUCTION:

Lumbar microdiscectomy is widely performed for disc herniation, however outcomes may be unsatisfactory in 10-40% patients and up to 12.5% require re-operation. Evidence regarding the effect of physical activity on post-operative outcomes is scant. The majority of existing studies rely on biased activity self-reporting or short-term monitoring. Duration of physical activity presents a tangible goal for patient counselling, can be measured using wearable technology, and can be targeted to improve outcomes.

METHODS:

53 patients underwent lumbar microdiscectomy and wore an accelerometer for 30 days post-operatively, which measured activity duration (lying, sitting, standing, walking, cycling) and intensity. Patient-reported outcome scores (VASB, VASL, ODI, EQ-5D, SF-12) at 1, 3, 6, and 12 months, and activity data were analysed. The primary outcome (treatment success) was a predetermined reduction in VASB, VASL, and ODI. The relationship between treatment success and activity was assessed using the Mann-Whitney U test. Associations between outcomes and activity were investigated using MANOVA and Pearson Correlations.

RESULTS:

Longer standing time was associated with worse ODI scores at 6 months (p = .034). There was no other statistically significant association between treatment success and activity duration or intensity. MANOVA demonstrated that shorter sitting time was associated with less back pain at 3 (p = .01) and 12 months (p = .011). Univariate analysis revealed that longer walking time was associated with improved EQ-5D scores at 3 (p = .001) and 12 months (p = .034), and improved SF-12 physical scores at 3 months (p = .026).

CONCLUSIONS:

Shorter standing time was associated with less disability, shorter sitting time with less back pain, and longer walking time with improved physical wellbeing after lumbar microdiscectomy. Higher-powered studies are needed to further explore the relationship between physical activity and outcomes.
499 Prospective, Randomized and Controlled Multicenter Study of Posterior Lumbar Facet Arthroplasty for the Treatment of Spondylolisthesis
Authors: Welch William Charles , Coric Domagoj , Nassr Ahmad , Steinmetz Michael P. , Whiting Donald M. , Groff Michael , Chi John , Whitmore Robert Gray , Meyer Scott , Arnold Paul M.
Published: March 2023

INTRODUCTION:

Prospective, Randomized and Controlled Multicenter Study of Posterior Lumbar Facet Arthroplasty for the Treatment of Spondylolisthesis.

METHODS:

The study was a prospective, randomized, controlled Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trial evaluating the investigational TOPS device to the control, transforaminal interbody fusion (TLIF) and pedicle screw fixation. Follow-up duration was a minimum twenty-four months.

RESULTS:

A total of 249 patients were evaluated comparing the investigational TOPS group (n = 170) to the control TLIF group (n = 79. There were no statistically significant differences between implanted levels (L4-5 TOPS 95%; L4-5 TLIF 95%) or blood loss. The overall composite measure for clinical success was statistically significantly higher in the TOPS group, 85%, compared to the fusion group, 64% (p = 0.0138). The percentage of subjects reporting minimum 15-point improvement in ODI showed a statistically significant difference (p-value = 0.037) favoring TOPS (94.0%) over TLIF (79.4%).

CONCLUSIONS:

This study demonstrates that posterior lumbar decompression and dynamic stabilization with the TOPS device is safe and efficacious in the treatment of lumbar stenosis with degenerative spondylolisthesis. Additionally, decompression and dynamic stabilization with the TOPS device maintains segmental motion.
508 Deep Learning Segmentation of the Nucleus Basalis of Meynert for Deep Brain Stimulation Surgical Planning
Authors: Doss Derek , Johnson Graham Walter , Narasimhan Saramati , Jiang Jasmine , Gonzalez Hernan F.J. , Paulo Danika Lea , Chang Catie , Morgan Victoria , Constantinidis Christos , Dawant Benoit M. , Englot Dario J.
Published: March 2023

INTRODUCTION:

The nucleus basalis of Meynert (NBM) is a subcortical structure involved in arousal and cognition being explored as a deep brain stimulation (DBS) target for Alzheimer’s disease and other disorders. Given the small size of the NBM and variability between patients, accurate patient-specific targeting for DBS is needed. Accurate patient-specific manual segmentation is possible but requires high resolution 7T MRI. Therefore, the current standard is a non-patient-specific probabilistic atlas (Zaborszky 2008).

METHODS:

Paired 3T and 7T MRI datasets of 21 healthy subjects were obtained and the NBM was expertly segmented on 7T MRI. The 7T NBM segmentation was then used on the 3T MRI. To increase generalizability, we augmented the dataset to a total of 210 images. An external dataset of 14 patients with temporal lobe epilepsy (TLE) was used to validate the network’s performance on brains with pathological changes (Alvim 2016). A 3D-Unet convolutional neural network was constructed, and a 5-fold cross-validation was performed for model selection. The model was evaluated on healthy subjects using the held-out test dataset and on the external dataset of 14 TLE patients.

RESULTS:

When tested on the held-out dataset, the deep learning network demonstrated significantly improved dice coefficient compared against the probabilistic atlas for both healthy subjects (0.68 ± 0.08, 0.47 ± 0.06) and patients with TLE (0.63 ± 0.08, 0.38 ± 0.19). Additionally, the centroid distance was significantly decreased when using the network in patients with TLE (1.22 ± 0.33 mm, 3.25 ± 2.57 mm).

CONCLUSIONS:

We developed the first network, to our knowledge, for automatic and accurate patient-specific segmentation of the NBM using deep learning. The proposed network has less error than accepted targeting margins. This segmentation strategy allows accurate patient-specific targeting of the NBM for DBS.
509 Modern Hearing Preservation Outcomes After Vestibular Schwannoma Stereotactic Radiosurgery
Authors: Berger Assaf , AlzateRamirez Juan , Bernstein Kenneth , Mullen Reed , McMenomey Sean , Jethanemest Daniel , Friedmann David R. , Smouha Eric , Sulman Erik P. , Silverman Joshua S. , Roland J. Thomas , Golfinos John G. , Kondziolka Douglas
Published: March 2023

INTRODUCTION:

For patients with vestibular schwannoma (VS), stereotactic radiosurgery (SRS) has proven effective in controlling tumor growth, while hearing preservation remains a key goal.

METHODS:

During the years 2013-2018, 353 patients underwent Gamma-knife surgery for VS at our institution. We followed 175 patients with pre-SRS serviceable hearing (Gardner-Robertson Score, GR 1 and 2). Volumetric and dosimetry data were collected, including Biological Effective Dose (BED), integral doses (ID) of total and intra-canalicular (IC) tumor components and hearing outcomes.

RESULTS:

Mean age was 56 years, 74 (42%) had baseline GR of 2, and mean cochlear dose was 3.5 Gy. Time to serviceable hearing loss (GR 3-4) was 38 months (95% CI, 26-46), with 77% and 62% hearing preservation in the 1st and 2nd years. Patients optimal for best hearing outcomes were younger than 58 with baseline GR of 1, free canal space 0.041cc (diameter of 4.5 mm) and mean cochlear dose <3.1 Gy. For such patients, hearing preservation rates were 92% by 12 months and 81% by 2 years, staying stable for >5 years post-SRS, significantly higher than the rest of the population.

CONCLUSIONS:

Hearing preservation after SRS for VS patients with serviceable hearing is correlated to the specific baseline GR score (1 or 2), age, cochlear dose and BED. Increased tumor-free canal space correlates with better outcomes. The most durable hearing preservation correlates with factors commonly associated with smaller tumors away from the cochlea.
516 Functional Impact of Intratumoral Heterogeneity in Therapeutic Vulnerabilities Across Enhancing and Non-Enhancing Tumor Components of Glioblastoma: A Paradigm-Shifting Personalized Medicine Approach
Authors: Garcia Diogo P. , Lin Wan-hsin , Brooks Mieu , Feathers Ryan , Middlebrooks Erik , Chaichana Kaisorn L. , Anastasiadis Panagiotis , Quinones-Hinojosa Alfredo
Published: March 2023

INTRODUCTION:

Glioblastoma (GBM) remains a fatal disease without effective targeted therapeutics. This is largely attributed to molecular and spatial heterogeneity and absence of clinically applicable models to guide patient care. Moreover, as standard surgical resection is aimed at contrast-enhancing (CE) tumor, the molecular landscape and treatment response of the remaining non-contrast enhancing (nCE) component remains unknown despite its active role in tumor progression and local recurrence.

METHODS:

Freshly resected tumor tissue was subjected to the generation of 3D tumor models (brain tumor initiating-enriched cell lines [BTICs] and microcancers). To identify the best treatment strategy, a panel of 25 brain penetrant drugs (alone/ in combination) targeting GBM drivers (i.e. RTK/Ras/PI3K, RB, p53/apoptosis, DNA damage repair, transcription addiction) was developed and used to test therapeutic vulnerabilities. Comprehensive sequencing including genome and transcriptome profiling and pathway analysis from these different tumor regions is ongoing.

RESULTS:

Thirty-two patients have been prospectively enrolled, with generation of 38 microcancers and 17 BTICs, and drug screening completed in 26 patients. For a subset, four tumor regions (two CE and two nCE) were collected under neuronavigation. Among 25 drugs tested, 5 ± 3 (mean ± SD) treatment strategies showed strong (≥70%) growth inhibition at Cmax, with inter-tumor drug response heterogeneity ranging from 18.9% to 5.4% (p = 0.02). Intra-tumor drug response heterogeneity varied from high (5/25 drugs tested) to low (0/25, p < 0.05) and was independent of enhancement status or spatial proximity.

CONCLUSIONS:

This is the first study to systematically assess treatment response from both CE and nCE patient-derived GBM models. By interrogating molecular landscapes and vulnerability profiles, we will be able to personalize and prioritize effective targeted interventions for GBM treatment.
521 An Integrated Workflow for Identification, Enrichment, and Molecular Profiling of Tumor-Derived and Non-Tumor Derived Plasma Extracellular Vesicles in Glioblastoma Patients
Authors: Aibaidula Abudumijiti , Fain Cori , Garcia Luz Cumba , Jung Mi-Yeon , Johnson Aaron J. , Parney Ian F.
Published: March 2023

INTRODUCTION:

Molecular analysis of bulk glioblastoma plasma EVs has demonstrated tumor-associated miRNA expression profiles. It remains unclear whether this molecular signature originates from tumor EVs or non-tumor EVs. Elucidating differences in molecular cargo in EVs originating from different cells could potentially identify highly specific EV biomarkers for glioblastoma diagnosis and disease progression monitoring.

METHODS:

EVs were isolated in vitro from human glioblastoma cells (dBT116)and CD14+ monocytes alone and as co-cultures +/- 5-amino levulinic acid (5-ALA) treatment. CD11b (myeloid marker) and protoporphyrin IX (tumor marker) expression were determined by flow cytometry. In addition, an EV characterization panel including 9 EV markers was further developed for GBM plasma samples. All assays and controls were performed per published guidelines. We utilized spectral flow cytometry to establish our gating strategy then used standard flow cytometry sorting to enrich plasma EVs into different subpopulations. LC-MS/MS proteomics was performed on sorted EVs.

RESULTS:

Protoporphyrin IX positivity was specific to tumor derived EVs. Rigorous assay controls confirmed that our EV characterization panel followed the current ISEV guideline for EV flow cytometry study. Our integrated workflow characterizes and can enrich plasma EVs with high efficiency, confirmed by the presence of multiple EV-associated proteins in proteomic analysis. Initial proteomic analysis suggests protoporphyrin IX-positive tumor EVs have unique protein expression profiles compared to CD11b-positive myeloid EVs.

CONCLUSIONS:

In this study, we were able developed an integrated workflow characterizing plasma EVs and enriching them into different subpopulations based on cell of origin. Application of this workflow in future larger cohorts will be conducted to identify additional specific plasma EV biomarkers for GBM.
523 Deep Phenotyping Reveals Germline Determinants of Disease Severity in Neurofibromatosis Type 2
Authors: Celano Emma , Asuzu David , Chittiboina Prashant
Published: March 2023

INTRODUCTION:

Although germline nonsense and frameshift mutations are hypothesized to confer more severe disease in neurofibromatosis type 2 (NF2), the mechanisms of genotype-phenotype association are unknown.

METHODS:

Patients (n = 169) with NF2 were enrolled in a natural history study (NCT NCT00598351). Deep phenotypic profiles were created (serially for 5 years) including clinical evaluations, self-reported functional measures, lifetime interventions (surgical, radiation and drug treatments), and imaging (tumor number, type, and volume). CLIA certified germline mutation analyses (n= 69) were supplemented with a custom PCR panel (NF2, LZTR1, SMARCB1, SMARCE1, and SUFU). Data were analyzed (QIAGEN CLC Genomics Workbench) for mutation type, location, and predicted protein effect (truncating/non-truncating). Low frequency variant detection was used to detect mosaicism.

RESULTS:

Germline mutations (nonsense-36%, splice-site-16%, and large deletions-16%) were grouped by predicted protein effect (truncating-41%, non-truncating-27%, and mosaic-33%) and mapped to the chromosomal locus. As predicted, disease severity increased in patients during the study (mean increase of 1.9 tumors/5-yrs and 3,793mm3/5-yrs). However, the disease severity was not associated with age at study enrollment (tumor number/volume) (p = 0.15/0.58). We found that truncating mutations in exons 8, 11-12 were associated with a higher tumor burden (p = 0.03). Truncating mutations at exon 8 were also associated with schwannomas (p = 0.04). Change in tumor volume during the study was predicted by younger age (p < 0.01) and truncating mutation (p = 0.05). Unlike prior studies, mortality was not predicted by truncating mutation type.

CONCLUSIONS:

We deeply phenotyped a diverse cohort of patients with NF2 and found that the location of truncating mutation determined the phenotype. We suspect that truncating mutations at exons 8 & 11-12 disrupt the transition from highly conserved FERM domain to the alpha-helix region leading to a severe NF2 phenotype.
556 A Matched-Pair Analysis of Patients with Ischemic Strokes Undergoing Thrombectomy Using the BOBBY Balloon Guide Catheter
Authors: Kim Lily H. , Choi John H. , Wolman Dylan , Pendharkar Arjun Vivek , Dodd Robert L. , Do Huy M. , Heit Jeremy , Telischak Nicholas
Published: March 2023

INTRODUCTION:

Endovascular thrombectomy has become the standard-of-care in treatment of large-vessel occlusion. Despite evidence of enhanced clot retrieval with balloon guide catheters (BGC), their routine use is yet to be widely adopted possibly due to incompatibility of past generation BGCs with large bore intermediate catheters. The next-generation BOBBY BGC is compatible with the 0.070-inch SOFIATM Flow Plus catheter.

METHODS:

We conducted a retrospective study of 112 thrombectomy cases utilizing BGC (N = 56) and non-BGC (N=56) methods. Sixty consecutive thrombectomy cases that used BOBBYTM BGC (MicroVention, Aliso Viejo, CA) at a single institution between 2/2021-3/2022 were identified. Of them, 56 BGC cases were 1:1 matched with non-BGC cases performed between 4/2016-12/2021 by proceduralists, age (±10 years), gender, stent retriever + aspiration device versus aspiration-only, and site of occlusion. First-pass effect was defined as Thrombolysis In Cerebral Infarction scale ≥IIB with a single pass, and good functional outcome as Modified Rankin Scale ≤2.

RESULTS:

BGC and non-BGC cohorts had similar mean age (67 versus 69 years), gender distribution (44.6%, 48.2% females), mean initial National Institutes of Health Stroke Scale (14.5, 14), and median pre-treatment ischemic core volumes (12.5 ml, 11 ml). BGC and non-BGC cases had similar rates of single pass (58.9%, 55.4%), first-pass effect (57.1%, 50.0%), and complications (5.4%, 8.9%). In aspiration-only cases, adding BGC led to a significantly higher rate of first-pass effect (71.4% vs 50.0%, P = 0.01). BGC was associated with higher likelihood of achieving good functional outcome at discharge (OR 2.30, P = 0.01). No additional procedural time was required for BGC cases (46.7 versus 48.4 minutes).

CONCLUSIONS:

An initial one-year experience from a tertiary academic center shows BGC can be safely adopted with comparable procedural efficacy, benefits to aspiration-only techniques, and earlier functional improvement when compared to conventional guide catheter cases.
558 Use Of Balloon-Guide Catheters For Concomitant Mechanical Thrombectomy And Carotid Revascularization With Flow-Arrest Results In Significantly Lower sICH And Better 90-Day Outcomes In Tandem Stroke Patients: A Propensity Score-Matched Study
Authors: Baig Ammad , Waqas Muhammad , Cappuzzo Justin Mark , Kuo Cathleen , Donnelly Brianna , Monteiro Andre , Davies Jason , Siddiqui Adnan Hussain , Levy Elad I.
Published: March 2023

INTRODUCTION:

A larger than normal clot burden accounts for worse presentation and poorer thrombectomy outcomes in tandem stroke cases.

METHODS:

A prospectively maintained database was retrospectively searched for patients who presented with a tandem stroke. Patients were dichotomized into two groups; those treated with BGCs and those treated without BGCs. A one-to-one matched propensity score analysis was performed to adjust for treatment selection bias using the nearest-neighbor matching technique for covariates (baseline comorbidities and stroke severity). Patient demographics, presentation characteristics, and procedural details were recorded. Outcomes were assessed as periprocedural sICH, in-hospital mortality, and 90-day mRS. Mann-whitney U test, and multivariate logistic regression was performed to compare the procedural parameters and the clinical outcomes between groups.

RESULTS:

We included 125 patients (BGC: 85 [40 after PSM]; No BGC: 40 [40 after PSM]). Concomitant carotid revascularization (stenting or angioplasty) was performed in all cases. After PSM, no difference was seen between the two groups in terms of comorbidities, and initial stroke severity. BGC group had significantly lower procedure duration (61.5% vs. 77.9% (OR = 0.996; P = 0.006)), lower NIHSS at discharge (8.0% vs. 11.0% (OR = 0.987; P = 0.042)), and higher odds of good outcomes (mRS 0-2 at 90-day) (52.3% vs. 27.5% (OR = 0.34; P = 0.040)). On multivariate regression analysis, BGC group had significantly higher rate of first-pass effect (mTICI 2B-3) (OR = 0.660, 95% CI = 0.480-0.908;P = 0.013), and a lower periprocedural sICH rate (OR = 0.615, 95% CI = 0.406-0.932; P = 0.025). No difference in in-hospital mortality was observed (OR = 1.591; 95% CI = 0.976-2.593; P = 0.067).

CONCLUSIONS:

Use of BGCs for concomitant mechanical thrombectomy and carotid revascularization with flow-arrest is safe and results in superior clinical and angiographic outcomes in tandem stroke patients.
559 Novel Technique of Head-Mounted Augmented Reality Assisted Cerebral Angiogram: Proof of Concept on a Flow Model
Authors: Costa Matias , Basamh Mohammed , Monteith Stephen J.
Published: March 2023

INTRODUCTION:

Augmented reality (AR) is an emerging technology in medicine while still under-explored in the endovascular field.

METHODS:

A 5 French guide was delivered to the proximal ICA-equivalent vessel. DynaCT was performed for the flow model using a uniplanar Artis Q angiogram suite (Siemens Medical Solutions, Erlangen, Germany) to create a CTA to act as a surrogate for non-invasive CTA in patients. A 3D reconstruction of the circulation was performed using the Syngo station (Siemens Medical Solutions, Erlangen, Germany). After importing the 3D image to the HMAR system, a hologram of the circulation was created. A roadmap image was created and the AR hologram was superimposed to it on the angiography screen. A 0.012” microcatheter with a microwire was then advanced to the tip of the guide catheter.

RESULTS:

The operator navigated the proximal and distal intracranial vessels using the hologram to replace the roadmap; and fluoroscopy guidance for visualization of the catheters and microwire. No contrast was needed as the hologram acted as the roadmap. The microcatheter was navigated successfully to distal targets in the ipsilateral and contralateral intracranial vasculature without the need to repeat road maps or inject contrast.

CONCLUSIONS:

The concept of HMAR-assisted cerebral angiography is feasible. We were able to perform the whole intracranial navigation using one pre-operative CTA only. This technology needs further development and has huge potential to decrease contrast use and possibly radiation exposure.
645 Getting What You Pay For: Impact of Copayments on Physical Therapy Initiation, Timing, and Continuation for Acute-Onset Low Back Pain
Authors: Jin Michael Chuwei , Jensen Michael , Barros Guinle Maria Isabel , Ren Alexander , Zhou Zeyi , Zygourakis Corinna Clio , Desai Atman , Veeravagu Anand , Ratliff John K.
Published: March 2023

INTRODUCTION:

Physical therapy (PT) is an important component of acute low back pain (LBP) management. Despite established guidelines, heterogeneity in medical management remains common.

METHODS:

The IBM Watson Health MarketScan claims database was queried for adult patients with new-onset idiopathic LBP. The primary outcomes-of-interest were timing and overall utilization of PT services. Additional outcomes-of-interest included timing of opioid prescribing. Actual and inferred copayments based on specialist visit claims were used to evaluate the relationship between PT copayment and incidence of PT initiation. Multivariable regression models were used to evaluate factors influencing PT usage.

RESULTS:

Overall, 2,467,389 patients were included. PT initiation, among those with at ≥1 PT service during the year after LBP diagnosis (30.6%), occurred at a median of 8 days post-diagnosis (IQR 1-55). Among those with at least one PT encounter, incidence of subsequent PT visits was significantly lower for those with high initial PT copayments. High initial PT copayments, while inversely correlated with PT utilization, were directly correlated with subsequent opioid use. High PT copayments affected relative timing of PT and opioid initiation, with every $10 increase associated with a delay in PT initiation of 3.06 days (95%CI 2.76-3.36) and an advancement of opioid prescription by 2.58 days (95%CI 2.24-2.92). For multivariable whole-cohort analyses, incidence of PT initiation among patients with inferred copayments in the 50-75th and 75th-100th percentiles was significantly lower than those below the 50th percentile (HR = 0.893 [95% CI 0.887-0.899] and HR=0.905 [95% CI 0.899-0.912], respectively).

CONCLUSIONS:

Higher PT copayments correlated with reduced PT utilization; higher PT copayments and lower opioid copayments were independent contributors to delayed PT initiation and higher opioid use. In patients covered by plans charging high PT copayments, opioid use was significantly higher. Co-pays impact long-term adherence to PT.
665 A Nationwide Study Characterizing the Risk and Outcome Profiles of Multilevel Fusion Procedures in Neuromuscular Scoliosis Patients With Neurofibromatosis Type 1
Authors: Price Gabrielle , Martini Michael Louis , Caridi John M. , Lau Darryl , Oermann Eric Karl , Neifert Sean N.
Published: March 2023

INTRODUCTION:

Spine abnormalities are a common manifestation of Neurofibromatosis Type 1 (NF1); however, the outcomes of surgical treatment for NF1-associated spinal deformity are not well explored.

METHODS:

The National Inpatient Sample was queried for NF1 and non-NF1 patient populations with neuromuscular scoliosis who underwent multilevel fusion surgery involving eight or more vertebral levels between 2004 and 2017. Multivariate regression modeling was used to explore the relationship between perioperative variables and pertinent outcomes.

RESULTS:

Of the 55,485 patients with scoliosis, 533 patients (0.96%) had NF1. Patients with NF1 were more likely to have comorbid solid tumors (p < 0.0001), clinical depression (p < 0.0001), peripheral vascular disease (p < 0.0001), and hypertension (p<0.001). Following surgery, NF1 patients had a higher incidence of hydrocephalus (0.6% vs. 1.9% p=0.002), seizures (4.9% vs. 5.7% p = 0.006), and accidental vessel laceration (0.3% vs. 1.9% p = 0.011). Although there were no differences in overall complication rates or in-hospital mortality, multivariate regression revealed NF1 patients had an increased probability of pulmonary (OR 0.5, 95% CI 0.3-0.8, p = 0.004) and neurological (OR 1.8, 95%CI 1.0-3.3, p = 0.053) complications. There were no significant differences in utilization, including non-home discharge or extended hospitalization; however, patients with NF1 had higher total hospital charges (OR -$18739, SE 3384, p < 0.0001).

CONCLUSIONS:

These findings indicate that NF1 is associated with certain complications following multilevel fusion surgery but does not appear to be associated with differences in quality or cost outcomes. These results provide some guidance to surgeons and other healthcare professionals in their perioperative decision making by raising awareness about risk factors for NF1 patients undergoing multilevel fusion surgery. We intend for this study to set the national baseline for complications after multilevel fusion in the NF1 population.
666 Comparison of Minimally Invasive and Open Surgical Approaches for Intradural-Extramedullary Spine Tumors: A Systematic Review and Meta-Analysis
Authors: Urooj Faiza , Baig Ahmer Nasir , Bajwa Mohammad Hamza , Shamim Shahzad M.
Published: March 2023

INTRODUCTION:

Traditionally spinal intradural-extramedullary (ID-EM) tumors have been accessed via open surgery. Removal of these tumors involves significant tissue damage, prolonged recovery, and risk of infection. More recent minimally invasive surgery (MIS) techniques aim to reduce these risks and complications while achieving similar goals of surgery as traditional approaches.

METHODS:

A systematic literature search was employed (PROSPERO#CRD42022302574) with searches through PubMed (MEDLINE), EBSCO, and Wiley Cochrane Library databases from conception till 9th January 2022. Cohort and case series studies with comparisons of minimally-invasive and open surgery for ID-EM spinal tumors were included; pooled sampled data were included in the random-effects (Mantel-Haenszel method) model for meta-analysis.

RESULTS:

Our search strategy yielded 403 total articles across these databases – after systematic review and exclusion, 13 studies were included for qualitative and quantitative analysis. On meta-analysis, minimally-invasive approaches were non-inferior to open surgery for achieving gross total resection (RR = 1.01, 95% CI 0.94 – 1.09, p = 0.78, I2 = 0%). Intraoperative blood loss (MD = -119.18, 95% CI -157.83 - -80.52, p < 0.0001, I2 = 89%), operative time (MD = -25.94, 95% CI -50.28 – -1.60, p = 0.04, I2 = 91%), and length of stay (MD=-2.50, 95% CI -3.89 – -1.10, p = 0.0004, I2 = 95%) were significantly lower within cohorts undergoing MIS surgery for ID-EM spinal tumor.

CONCLUSIONS:

Data within the reviewed studies suggest similar rates of gross total resection within MIS and open surgery cohorts for ID-EM spinal tumors. Moreover, MIS affords shorter hospital stays, decreased blood loss, and operative time for patients. For certain patient groups, MIS spinal tumor resection can be preferred over standard surgical approaches, with preservation of function and decreasing overall surgical complications.
668 Intraoperative Ultrasound Elastography is a Promising Technology to Quantify Reduced Spinal Cord Tension During Posterior Vertebral Column Subtraction Osteotomy for Recurrent Tethered Cord Syndrome
Authors: Judy Brendan F. , Kerensky Max , Hersh Andrew , Weber-Levine; Amanda Sacino Carly , Liu Ann , Jin Yike , Jiang Kelly , Young Lisa , Routkevitch Denis , Perdomo-Pantoja Alexander , Davidar Daniel , Manbachi Amir , Theodore Nicholas
Published: March 2023

INTRODUCTION:

Tethered cord syndrome (TCS) has been traditionally treated with detethering surgery.1,2 Posterior vertebral column subtraction osteotomy (PVCSO) is a novel surgery that can treat TCS while avoiding complications of detethering surgery, such as retethering or cerebrospinal fluid leaks.2-6 The pathophysiology of PVCSO is not completely understood. However, the hypothesis is that shortening the vertebral column decreases the spinal cord (SC) tension thereby improving neurological function. Intraoperative ultrasound elastography (USE) is well suited to elucidate the changes that can occur in SC parenchyma secondary to PVCSO.7,8 Through different modalities, such as superb microvascular imaging (SMI) and elastography (USE), US can analyze changes in blood flow and tissue tension.9

METHODS:

Three patients with recurrent TCS underwent PVCSO and intraoperative USE to analyze the tension of the SC at 3 timepoints: pre-, mid- and post-shortening.

RESULTS:

All three patients (two female, one male) had undergone multiple detethering surgeries. Prior to shortening, the median SC elasticity of all patients was 9.8 kPa (IQR 9.7-12.4 kPa). After complete compression of the rods, the SC elasticity decreased by 17.4% to 7.7 kPa (6.5-9.7 kPa). All patients had significant improvement in sensation and reduction in pain at their 2 month follow up appointment.

CONCLUSIONS:

Here we report the first use of USE to demonstrate decreased SC tension after PVCSO for TCS. All patients reported improved symptoms and USE demonstrated decreased SC tension after shortening. USE is a promising tool for evaluating tissue elasticity and blood flow in spinal pathologies, including TCS. This technology serves as an intraoperative confirmation that SC tension decreases after PVCSO. Patients and neurosurgeons both benefit from an intraoperative objective tool to demonstrate reduced SC tension.
675 Chemoprophylactic Anticoagulation Causes a Marked Decrease in Thromboembolic Events Following Lumbar Fusion: Causal Inferences from a Propensity-Matched Analysis of 1302 patients
Authors: Cloney Michael , Koski Tyler R. , Dahdaleh Nader S.
Published: March 2023

INTRODUCTION:

Chemoprophylactic anticoagulation is commonly used to prevent venous thromboembolic events (VTE) after lumbar fusion. However, the magnitude of the associated risk reduction is not well described, and conventional retrospective statistical methods preclude causal inferences from this association.

METHODS:

1302 consecutive lumbar fusions performed at our institution over a six-year period were identified, and relevant clinical and demographic data were collected. VTE events within 30 days postoperatively were identified. Patients who were given chemoprophylaxis and controls were matched according to age, body mass index, sex, Charlson Comorbidity Index, history of VTE, estimated blood loss, length of surgery, transfusion, whether surgery was staged, and whether surgery used an anterior approach. K-nearest neighbor propensity score matching was performed, and covariate adjustments were made to draw causal inferences regarding VTE rate.

RESULTS:

Unadjusted, there was no difference in the rate of VTE between patients who did (3.8%) and did notreceive chemoprophylaxis (4.4%, OR = 0.86 [0.47, 1.58], p = 0.667). On multivariable regression, and chemoprophylaxis was negatively associated with VTEs (OR = 0.38 [0.15, 0.95], p = 0.039). 589 lumbar fusion patients with and without chemoprophylaxis were successfully matched. After matching, median bias was 1.9%, and overall known bias was reduced by a median of 91.4%. After matching, covariates were well balanced (Rubin's B = 21.8). A covariate adjusted logistic regression model confirmed that chemoprophylaxis was associated with reduced odds of VTE (OR = 0.40 [0.16, 0.98], p = 0.044). The average treatment effect of chemoprophylaxis was a reduction in VTE of 3.7%. The only instance of epidural hematoma occurred in the control group.

CONCLUSIONS:

Among patients undergoing lumbar fusions, chemoprophylactic anticoagulation causes a marked decrease in VTE.
745 Medical Student Specialty Decision Making by Gender: Perceptions of Neurosurgery
Authors: Pugazenthi Sangami , Johnson Gabbie , Lee Hedwig , Strahle Jennifer
Published: March 2023

INTRODUCTION:

Although 50% of medical school graduates are female, less than 30% of neurosurgery residency applicants are female and less than 10% of neurosurgeons are female. More information is needed to understand the disproportionately low interest in neurosurgery for female medical students.

METHODS:

A Qualtrics survey was administered at Washington University School of Medicine to survey all MD/MD-PhD students to assess factors influencing medical student specialty decision making and perceptions of neurosurgery. Likert scale responses converted to numerical values on a 5-point scale were analyzed by Mann Whitney-U tests. Chi Squared analyses were performed on binary responses.

RESULTS:

Of the 131 respondents (31% response rate), 62.6% were female. When making specialty decisions, female students considered maternity/paternity leave more (P = 0.028) and salary less than their male counterparts (P = 0.072). There was no significant difference between genders in consideration of perceived happiness of people in the field, intellectual interest, perceived fit in the field, work/life integration, length of training, or having a mentor in the field, or research opportunities. Female students were more hesitant toward neurosurgery due to maternity/paternity needs (P = 0.031), and technical skill required (P = 0.020). Across both genders, the majority of medical students were hesitant towards neurosurgery due to opportunities for work/life integration (93%), length of training (88%), malignancy of the field (76%), and perceived happiness of people in the field (76%).

CONCLUSIONS:

Compared to male students, female medical students value maternity/paternity needs more in the specialty decision making process and are hesitant toward pursuing neurosurgery due to maternity/paternity needs.
746 PGY-6 Versus PGY-7 Neurosurgical Chief Year: A Survey of Residents and Program Directors
Authors: Mooney James Henry , Salehani Arsalaan , Shannon Chevis , Rozzelle Curtis
Published: March 2023

INTRODUCTION:

Recently, more neurosurgical residency programs have transitioned from a post-graduate year (PGY)-7 to a PGY-6 chief year. There has not been a national analysis of resident and program director perceptions regarding the timing of chief year conductance and its influence on overall program satisfaction.

METHODS:

An online survey was distributed via individual institution program coordinators to all North American PGY 4-7 residents and program directors. Data regarding program size, protected research timing, chief year timing (PGY-6 vs PGY-7) and resident and program director perceptions of the influence of neurosurgical chief year timing on program satisfaction and ability of residents to practice were recorded. Survey results were summarized descriptively.

RESULTS:

A total of 134 respondents completed the survey. Thirty-five percent of respondents reported a recent program transition from a PGY-7 to PGY-6 chief year while 44% of respondents at programs conducting a PGY-7 chief year reported they were interested in transitioning to a PGY-6 chief year. The large majority of residents (76%) and program directors (80%) at PGY-6 chief year programs stated they were overall satisfied with this. A greater percentage of residents (54%) reported a positive impact of PGY-6 chief year on patient care and preparation to practice when compared to program directors (8%). A large percentage (>80%) of all respondents reported that a PGY-6 chief year provided increased opportunity for subspecialty focus, enfolded fellowships and career planning.

CONCLUSIONS:

Program directors and residents at PGY-6 chief year program s report a high level of satisfaction with many of those at PGY-7 programs desiring to make this transition. A PGY-6 chief year may allows for greater sub-specialty focus and career planning during the PGY-7 year and its impact on programs should be investigated further.