bluuebunny/crossref_metadata_2025_split huggingface dataset:
351 Dear Program Director: Evaluating Implicit Bias in Neurosurgery Residency Letters of Recommendation
Authors: Graves Erin , Coyle Anne , Erkmen Cherie , Erkmen Kadir 
Published: March 2022

INTRODUCTION:
Despite comprising half of medical students, women represent 25% of neurosurgery applicants, 17% of residents and 12% of practicing neurosurgeons. This trend suggests “leaks” in the career pipeline for female neurosurgeons.
The NRMP Program Director Survey has shown that neurosurgery programs identify Step 1 score and letters of recommendation (LORs) as the most important factors in selecting applicants to interview. Other specialties have evaluated implicit biases in LORs, but no such study exists in neurosurgery.

METHODS:
Retrospective analysis of LORs for neurosurgery applicants interviewed between 2014-2020. LORs were evaluated using the Linguistic Inquiry & Word Count (LIWC) software and a Reader Scoring System. The LIWC dictionary and a custom dictionary containing additional categories (e.g. grindstone) and terms (e.g. hardworking) were used. Analyses were done using SAS.

RESULTS:
218 applications were reviewed (81.1% male, n=177), for a total of 827 letters. LIWC analysis showed significant differences in word count (331 females vs. 296 males, p = 0.017), ability words (6.61 females vs. 5.51 males, p = 0.018), and agentic words (6.31 females vs. 5.53 males, p = 0.020). Female letters showed a higher average number of grindstone, communal and commitment words. The Reader Scoring System showed similarities between candidates, but revealed a trend that in female letters writers mention personal attributes and “career” versus “residency” potential.

CONCLUSION:
This is the first study to evaluate for implicit gender bias within neurosurgery LORs. LORs are key in the selection process and therefore represent one area to target when it comes to increasing female representation in neurosurgery. Our study showed that female applicant’s letters were longer, had more ability and agentic terms, and trended towards more grindstone, communal and commitment words.
356 Patient-and-Hospital-Related Risk Factors for Non-Routine Discharge After Lumbar Decompression and Fusion for Spondylolisthesis
Authors: Elsamadicy Aladine A. , Freedman Isaac G. , Koo Andrew B. , David Wyatt , Hengartner Astrid , Havlik John , Hersh Andrew , Pennington Zach , Kolb Luis , Laurans Maxwell S. H. , Shin John H. , Sciubba Daniel 
Published: March 2022

INTRODUCTION:
In various spinal surgeries, non-routine discharges have been associated with inferior outcomes. However, there exists a paucity of data regarding the relationship between non-routine discharge and quality of care among patients with spondylolisthesis.

METHODS:
A retrospective cohort study was performed using the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database from 2010 through 2016. Adult patients (=18 years old) who underwent spinal decompression and fusion for lumbar spondylolisthesis were identified using ICD-9-CM diagnosis and CPT procedural coding systems. The study population was divided into two cohorts based on discharge disposition: routine (RD) and non-routine discharge (NRD). A multivariate logistic regression model was used to identify the independent predictors of non-routine discharge and 30-day unplanned readmission.

RESULTS:
A total of 5,252 patients were identified, of which of which 4,316(82.2%) had a RD and 936 (18.8%) had a NRD. The NRD cohort tended to be older (p<0.001) and have a higher BMI (p<0.001). Patients who experienced a NRD had a longer LOS (NRD: 4.7±3.7 days vs RD: 3.1±2.0 days, p<0.001), a higher proportion of adverse events (p<0.001), higher rates of reoperation (p=0.005) and unplanned 30-day readmission rates (p<0.001). On multivariate regression analysis, age [OR: 1.08, 95% CI (1.06–1.10),p<0.001], female sex [OR: 2.01, 95% (1.51–2.69),p<0.001], non-Hispanic Black race/ethnicity [OR: 2.10, 95% CI (1.36 – 3.24), p=0.001], BMI [OR: 1.03, 95% CI (1.01–1.05), p=0.007), dependent functional status [OR: 3.33, 95% CI (1.59 – 6.99),p=0.001], malnourishment [OR: 2.14, 95% CI (1.27 – 3.62, p=0.005], and LOS [OR: 1.26, 95% CI (1.18 – 1.33),p<0.001] were all independent predictors for NRD. However, NRD did not independently predict an unplanned 30-day readmission on multivariate analysis.

CONCLUSION:
In our study we found that on univariate analysis NRD was associated with increased adverse events, length of stay and 30-day unplanned readmission. When controlling for patient- and hospital-related factors, we found that female sex, non-Hispanic Black race, BMI, dependent functional status, malnourishment and longer LOS were independently associated with NRD.
402 Cost-Effectiveness Analysis on Small (<5 mm) Unruptured Intracranial Aneurysm Follow-up Strategies
Authors: Salih Mira , Salem Mohamed M. , Moore Justin M. , Thomas Ajith J. , Ogilvy Christopher S. 
Published: March 2022

INTRODUCTION:
Unruptured intracranial aneurysms are frequently detected during routine clinical diagnostic processes. A significant portion is small aneurysms less than 5mm. While follow-up patients with small aneurysms have been advocated, the cost-effectiveness of such care and the optimal follow-up interval remain unknown.

METHODS:
A decision analysis study was performed utilizing a Markov model with Monte Carlo simulations to simulate patients undergoing follow-up by MRA at different time intervals (1-,2-,3-, 5-and 7-year intervals) for small (<5mm) unruptured intracranial aneurysms. Input data for the model was extracted from the current literature, primarily latest Meta-analysis. Probabilistic sensitivity analysis and deterministic sensitivity analyses were performed to evaluate the robustness of the Model.

RESULTS:
Given current literature and our model, following-up every 3 years with noninvasive imaging is the most cost-effective strategy (cost = $99611, effectiveness = 19.00 QALYs), showing the highest net monetary benefit. The conclusion remains robust in probabilistic sensitivity analysis and deterministic sensitivity analyses. As the annual rupture risk of small aneurysms exceeds 9.8% (base-case 3.1%), following up every 2 years becomes the optimal strategy.

CONCLUSION:
The most cost-effectiveness follow-up strategy for small (<5mm) unruptured aneurysms using MRA is follow-up every 3 years. More frequent follow-up strategies or prompt preventive treatment would be more appropriate in patients with a higher rupture risk of growing aneurysms.
405 Volumetric Quantification of Subarachnoid Hemorrhage Independently Predicts Hydrocephalus and Seizures
Authors: Daou Badih J. , Khalsa Siri S. S. , Anand Sharath , Williamson Craig , Rajajee Venkatakrishna , Sheehan Kyle , Pandey Aditya S. 
Published: March 2022

INTRODUCTION:
Hydrocephalus and seizures greatly impact outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH); however, reliable tools to predict these outcomes are lacking.

METHODS:
Total hemorrhage volume following aneurysm rupture was retrospectively analyzed on presentation CT imaging using a custom semi-automated computer program developed in MATLAB that employs intensity-based k-means clustering to automatically separate blood voxels from other tissues. Volume data was added to a prospectively maintained SAH database. Through logistic regression analysis, we evaluated the association of hemorrhage volume with shunted-hydrocephalus and seizures and evaluated the diagnostic accuracy by evaluation of the area under the receiver operating characteristic curve (AUC).

RESULTS:
288 consecutive patients with aSAH comprised the study population. Mean total hemorrhage volume was 74.9 ml. Thirty-eight patients developed seizures (13.2%). Mean hemorrhage volume in patients who developed seizures was significantly higher than patients with no seizures (mean difference 17.3 ml, P=0.01). In multivariate analysis, larger hemorrhage volume on initial CT scan and hemorrhage volume >50 ml (OR 2.81, P=0.047 CI 1.03-7.80) were predictive of seizures. 48 patients developed shunt-dependent hydrocephalus (17%). The mean hemorrhage volume in patients who developed shunt-dependent hydrocephalus was significantly higher than patients who did not (mean difference 17.2 ml, P=0.006). Larger hemorrhage volume and hemorrhage volume >50 ml (OR 2.45, P=0.03, CI 1.08-5.54) were predictive of shunt-dependent hydrocephalus. Hemorrhage volume had adequate discrimination for the development of seizures (AUC = 0.635) and shunted hydrocephalus (AUC = 0.629).

CONCLUSION:
Hemorrhage volume is an independent predictor of seizures and hydrocephalus in aSAH. Further evaluation of quantitative volumetric analysis may complement existing scales used in clinical practice and assist in prognostication and management.
425 Defining the Optimal Thermal Parameters for Sub-threshold Testing With Focused Ultrasound
Authors: Krishna Vibhor , Sammartino Francesco , Snell John W. , Eames Matthew 
Published: March 2022

INTRODUCTION:
Focused ultrasound ablation (FUSA) relies on accurate subthreshold testing to physiologically explore the presumed target before permanent ablation. However, the optimal thermal parameters for subthreshold testing (i.e., thermal dose and spot size thresholds) are not yet defined.

METHODS:
We performed a retrospective analysis of intraoperative testing data of essential tremor patients undergoing FUSA. Sonications with a thermal dose of less than 25 cumulative equivalent minutes (CEM) were classified as sub-threshold. The intraoperative writing samples were independently rated by two raters using the clinical rating scale for tremor. The association between thermal dose and tremor scores was statistically analyzed, and the thermal dose and spot size thresholds for tremor improvement were computed using leave-one-out cross-validation analysis.

RESULTS:
From the 331 pairs of sonications and tremor assessments, 97 sonications were classified as subthreshold sonications. Intraoperative tremor improvement was observed in 23 (24%) subthreshold sonications with a median tremor improvement of 20% (interquartile range = 41.6) from the baseline. The thermal dose threshold for tremor improvement was 0.67 CEM (equivalent to 30 seconds thermal exposure at 430C). The spot size threshold for tremor improvement was 2.46 mm. VIM was exposed to TN thermal dose during sub-ablative and ablative sonications.

CONCLUSION:
The optimal thermal dose and spot size thresholds for subthreshold testing are significantly higher than the current FUSA standard-of-care. We recommend long duration (>30 seconds), subthreshold sonications for intraoperative testing during FUSA. Future investigations should test whether the thermal dose threshold is tissue-specific and determine the mechanisms underlying focused ultrasound TN.
431 Chronic Opioid Use Prior to ACDF Surgery is Associated With Inferior Post-operative Outcomes
Authors: Rodrigues Adrian , Varshneya Kunal , Veeravagu Anand 
Published: March 2022

INTRODUCTION:
Anterior cervical discectomy and fusion (ACDF) is widely used in patients with radiculopathy, myelopathy, or spondylosis. This patient population has a higher rate of opioid use than the general public, but dedicated studies on pre-operative ACDF opioid use have not been conducted.

METHODS:
The MarketScan Database was queried from 2007-2015 to identify adult patients who underwent an ACDF procedure using CPT codes. Patients were then classified into three separate cohorts based on the number of separate opioid prescriptions in the 12 months before their ACDF, excluding the 30 days immediately before their operation: (1) opioid naÏve if 0 prescriptions, (2) mild opioid use if 1-4 prescriptions, and (3) chronic opioid use if =5 prescriptions. Patients with a history of neck fracture or arthrodesis were excluded. Continuous insurance enrollment was confirmed for each patient. Short term outcomes were compared between groups, and nearest-neighbor propensity-score matching was employed to match patient cohorts across measured covariates.

RESULTS:
Of 81,671 ACDF patients, 31,312 (38.34%) were opioid naÏve, 30,302 (37.10%) were mild users, and 20,057 (24.56%) were chronic users. At baseline, chronic opioid users had more comorbidities than patients with less frequent opioid use (mean Charlson Comorbidity Index (CCI): 2.06; SD (2.06) vs. opioid naÏve mean CCI: 1.77; SD (1.79)). Chronic opioid users had higher rates of post-operative complications than mild and non-users (p < 0.0001), and higher rates of readmission and reoperation. After matching opioid naÏve vs. chronic opioid users along demographic, comorbidity, and intra-operative characteristics, post-operative complications remained elevated for chronic opioid users relative to opioid naÏve patients (9.13% vs. 5.29%; p < 0.0001). Rates of readmission and reoperation also remained higher for chronic opioid patients, as did inpatient costs.

CONCLUSION:
Chronic opioid users had longer hospitalizations and higher rates of post-operative complication, readmission, and reoperation, on average, than mild opioid and opioid naÏve users. After balancing patients across observed covariates, including comorbidity burden, the outcome differences persisted, suggesting a durable association between pre-operative opioid use and negative post-operative outcomes.
433 Efficacy and Safety of Surgical Decompression for Migraine: A Systematic Review
Authors: Shahid Adnan , Abbasi Mehdi , Madhani Sarosh , Larco Jorge A. , Liu Yang , Robertson Carrie , Chiang Chia-Chun , Savastano Luis E. 
Published: March 2022

INTRODUCTION:
Migraine is a common disabling disease with high socioeconomic and personal impacts. Despite various medical options, many patients suffer refractory and chronic migraines. New surgical approaches are gaining traction as viable options to treat migraines.

METHODS:
The study was conducted in accordance with PRISMA guidelines. An inclusive search of several databases from January 1990 to December 2nd, 2020, was performed. Studies reporting various decompression approaches of peripheral nerves for chronic or refractory migraines were included and analyzed. The risk of bias of individual studies was assessed in accordance with the modified Newcastle-Ottawa Quality Assessment Scale. Only those studies representing their data of migraine with mean frequency and intensity of headache, as well as their complication event rate, were reported.

RESULTS:
Total, 22 studies comprising 1377 patients with migraines were included. Mean age of patients undergoing surgery was 44.22 (95% CI 42.96 - 45.48) years. Patients underwent surgery for migraine comprising decompression of supraorbital, supratrochlear, zygomaticotemporal, or occipital nerve. Most studies reported recovery from headache with improvement in mean headache frequency (range 4.4 to 16.6 days per month) and mean headache intensity (range 2.80 to 7.30 in visual analog scale). The risk of bias was high, with the bias being high in 10 studies and moderate in 11 studies. Total complication rate was 8.0% (95% CI 4.0%-13.0%) which included paresthesia, wound infection, and hypertrophic scarring in a follow-up duration of 2 to 66 months. Heterogeneity in outcome measures and moderate-to-high risk of bias in the majority of studies precluded for meta-analysis.

CONCLUSION:
Despite improvement in headache frequency and intensity reported on surgical decompression for migraine, available studies reported used variable outcome measures and had moderate-to-high risk of bias.
441 Prospective, Randomized, Double-Blinded Clinical Trial Comparing PEEK and Allograft Spacers in Patients Undergoing Transforaminal Lumbar Interbody Fusion Surgeries
Authors: Villavicencio Alan T. , Nelson Ewell L. , Rajpal Sharad , Burneikiene Sigita 
Published: March 2022

INTRODUCTION:
Allograft and polyether-ether-ketone (PEEK) radiographic, biomechanical, histological properties have been extensively studied and both spacers have their advantages and shortcomings. There are no comparative randomized or double-blinded spinal fusion clinical trials reported to date.

METHODS:
A prospective, randomized, controlled, double-blinded clinical trial was initiated at a single center. All patients were followed for 2 years ± 2 months; radiographic and clinical outcomes were assessed at 3, 6, 12 and 24 months with an additional follow-up at 3 weeks for radiographic assessment.

RESULTS:
A total of 138 patients undergoing transforaminal lumbar interbody fusions (TLIF) were randomized (1:1) to receive either cortical allograft or PEEK interbody lordotic spacers. RhBMP-2 was used in 96.7% allograft and 98.4% PEEK group patients. Although no differences were detected between the allograft and PEEK patient groups at any of the follow-up time points, there was a highly significant (p<0.0001) improvement in all clinical outcome measures. Overall, evidence of radiographic fusion was achieved in 118 (97.5%) patients at the 24 months follow-up. Three patients, all in the allograft group, had pseudoarthrosis and underwent revision surgeries. Postoperative improvement of sagittal alignment, anterior (ABH) or posterior body height (PBH) was initially achieved, but it was mainly lost or reduced at the final follow-up and there were no statistically significant differences between the groups. At the end of the study, improvement and maintenance of lumbar lordosis were achieved in 43.3% and 49.2% patients and segmental alignment in 38.3% and 36.1% for the allograft and PEEK patient groups, respectively. Similarly, ABH was improved and maintained in 28.3% and 36.1% patients and PBH in 28.3% and 44.3% for the allograft and PEEK groups, respectively.

CONCLUSION:
Although allograft-assisted surgeries may have reduced fusion rates, the study findings demonstrated that TLIF surgery with two different types of cages and in conjunction with rhBMP-2 resulted in similar radiological or clinical outcomes and a highly statistically significant improvement in all clinical outcome measures at the end of the study regardless of the randomization group.
449 Correcting Spinopelvic Parameters in Lumbar Scoliosis With Single Level TLIF
Authors: Chieng Lee O. , Perez-Cruet Mick J. 
Published: March 2022

INTRODUCTION:
Spinopelvic parameters are known to play important role in deformity correction. However, its long term implication in short segment degenerative lumbar pathology in the setting of lumbar scoliosis remains unknown. In this study, we sought to investigate the influence of single level TLIF on spinopelvic parameters for patients with degenerative lumbar scoliosis.

METHODS:
We performed retrospective analysis of patients who underwent single level TLIF for degenerative lumbar scoliosis. Medical comorbidities were included. Baseline and postop spinopelvic parameters were obtained from standing film. ODI and SF-36 were collected.

RESULTS:
107 patients with average age of 68.6 ± 12.7 years old underwent single level TLIF for degenerative scoliosis. 73.4% and 67.1% of the patients have symptomatic degenerative spinal stenosis and spondylolisthesis respectively. L4-5 was the most common level of fusion (70%). There was significant improvement of lumbar cobb angle from preop 21.6 ± 5.6 to 15.6 ± 3.6 (p < 0.05). Lumbar lordosis (LL) improved from 47.4 ± 14.4 to 55.9 ± 10.9 at 6 months postop. However no significant change in pelvic tilt, sacral slope or pelvic incidence (PI). Interestingly, significant improvement of PI- LL mismatch was observed from 16.3 ± 11.5 preop to 7.12 ± 12 postop. The ODI score improved from 38.1 preoperatively to 25.8 postoperatively at 1 year followup. Likewise SF-36 score increased significantly postop.

CONCLUSION:
Single level TLIF may be sufficient in treating selected cases of degenerative lumbar scoliosis with concurrent spinal stenosis and spondylolisthesis. Interestingly, there was robust improvement in both scoliotic curve and PI- LL mismatch with only 1 level fusion. Thereby, long segment lumbar fusion could be avoided or delayed.
451 Dural Tears in Full-Endoscopic Unilateral Laminotomies for Bilateral Lumbar Decompression
Authors: Kashlan Osama , Bergquist Julia , Prasse Tobias , Greil Madeline , Sivakanthan Sananthan , Williams John R. , Hofstetter Christoph P. 
Published: March 2022

INTRODUCTION:
Full-endoscopic unilateral laminotomy for bilateral lumbar decompression (ULBD) for spinal stenosis has proven benefits when compared to microscopic technique. Intraoperative laceration of the dura may be encountered and their optimal technique and effectiveness of full-endoscopic dural repair remains unclear.

METHODS:
For this analysis, we utilize a prospectively collected database of all patients undergoing ULBD from 2015 to 2021 at our institution. We evaluate whether patient specific factors such as sex, age, body mass index (BMI), smoking status, ASA level, number of levels, or previous index level surgery affects durotomy risk. We then determine whether having an intraoperative durotomy affects length of stay (LOS), revision surgery risk, length of time on postoperative pain medications, or Oswestry Disability Index (ODI) scores.

RESULTS:
In 174 patients undergoing ULBD, there were 11 patients who sustained intraoperative dural tears (6.3%). Utilizing our novel bimanual technique, there was only one patient who required temporary CSF drainage via a lumbar drain. None required revision surgery for CSF leak repair. Durotomy risk was not significantly affected by any patient specific risk factors. Sustaining a durotomy did increase LOS (p=0.033). Intraoperative durotomies did not affect revision surgery risk, or length of time on postoperative pain medications. Utilizing MCID of 12.8 increase in ODI, 70.8% of non-durotomy patients achieved the MCID goal versus 60.0% of durotomy patients. However this trend did not achieve statistical significance (p = 0.605).

CONCLUSION:
Our novel method of bimanual repair of CSF leaks in full-endoscopic spine surgery appears to be a safe and feasible. There are no patient specific risk factors affecting durotomy risk. Sustaining a durotomy intraoperatively affects LOS but does not significantly alter any other aspect of the postoperative course for patients undergoing ULBD.
476 Does Anticoagulation or Antiplatelet Therapy Increase Risk of Traumatic Subarachnoid Hemorrhage Progression?
Authors: Harland Tessa , Prabhala Tarun , Nardolillo Annie , Boulos Alan S. , Adamo Matthew , Dalfino John C. , Paul Allie , Entezami Pouya 
Published: March 2022

INTRODUCTION:
Isolated traumatic subarachnoid hemorrhage (tSAH) is a common finding of mild traumatic brain injury that often results in the transfer to a tertiary center. This is often done out of concern for patients on blood thinners (BT) who are thought to be at higher risk of clinical worsening.

METHODS:
A retrospective analysis identified patients over the age of 18 with isolated tSAH and a GCS of 15 on admission. Clinical information including use of BT, administration of reversal agents, radiographic progression, and need for neurosurgical intervention were collected. Patients on BT were divided into AP, AC and AP/AC groups based on drug type.

RESULTS:
384 patients were included with 203 in the non-BT group and 181 in the BT group. 2.1% had worsening scans and none required neurosurgical intervention. There was no difference in radiographic worsening between the non-BT and BT group (2.4% vs. 1.6%; p = 1.00). Crosswise comparison revealed no difference between the non-BT group and each BT subtype (AP, AP/AC, AC). The non-BT group was more likely to have radiographic improvement than the BT group (45.8% vs. 30.9%; p = 0.002).

CONCLUSION:
Neurologically intact patients on BT with isolated tSAH are not at increased risk of radiographic progression or need for neurosurgical management. Consequently, the presence of BT should not influence management decisions for increased surveillance.