Publications by authors named "Anand Veeravagu"

132 Publications

Factors which predict adverse events following surgery in adults with cervical spinal deformity.

Bone Joint J 2021 Apr;103-B(4):734-738

Neurosurgery AI Lab & Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA.

Aims: The aim of this study was to identify the risk factors for adverse events following the surgical correction of cervical spinal deformities in adults.

Methods: We identified adult patients who underwent corrective cervical spinal surgery between 1 January 2007 and 31 December 2015 from the MarketScan database. The baseline comorbidities and characteristics of the operation were recorded. Adverse events were defined as the development of a complication, an unanticipated deleterious postoperative event, or further surgery. Patients aged < 18 years and those with a previous history of tumour or trauma were excluded from the study.

Results: A total of 13,549 adults in the database underwent primary corrective surgery for a cervical spinal deformity during the study period. A total of 3,785 (27.9%) had a complication within 90 days of the procedure, and 3,893 (28.7%) required further surgery within two years. In multivariate analysis, male sex (odds ratio (OR) 0.90 (95% confidence interval (CI) 0.8 to 0.9); p = 0.019) and a posterior approach (compared with a combined surgical approach, OR 0.66 (95% CI 0.5 to 0.8); p < 0.001) significantly decreased the risk of complications. Osteoporosis (OR 1.41 (95% CI 1.3 to 1.6); p < 0.001), dyspnoea (OR 1.48 (95% CI 1.3 to 1.6); p < 0.001), cerebrovascular accident (OR 1.81 (95% CI 1.6 to 2.0); p < 0.001), a posterior approach (compared with an anterior approach, OR 1.23 (95% CI 1.1 to 1.4); p < 0.001), and the use of bone morphogenic protein (BMP) (OR 1.22 (95% CI 1.1 to 1.4); p = 0.003) significantly increased the risks of 90-day complications. In multivariate regression analysis, preoperative dyspnoea (OR 1.50 (95% CI 1.3 to 1.7); p < 0.001), a posterior approach (compared with an anterior approach, OR 2.80 (95% CI 2.4 to 3.2; p < 0.001), and postoperative dysphagia (OR 2.50 (95% CI 1.8 to 3.4); p < 0.001) were associated with a significantly increased risk of further surgery two years postoperatively. A posterior approach (compared with a combined approach, OR 0.32 (95% CI 0.3 to 0.4); p < 0.001), the use of BMP (OR 0.48 (95% CI 0.4 to 0.5); p < 0.001) were associated with a significantly decreased risk of further surgery at this time.

Conclusion: The surgical approach and intraoperative use of BMP strongly influence the risk of further surgery, whereas the comorbidity burden and the characteristics of the operation influence the rates of early complications in adult patients undergoing corrective cervical spinal surgery. These data may aid surgeons in patient selection and surgical planning. Cite this article:  2021;103-B(4):734-738.
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http://dx.doi.org/10.1302/0301-620X.103B4.BJJ-2020-0845.R2DOI Listing
April 2021

Risk Factors for Revision Surgery After Primary Adult Thoracolumbar Deformity Surgery.

Clin Spine Surg 2021 Jan 11. Epub 2021 Jan 11.

Neurosurgery AI Laboratory and Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA Department of Neurosurgery, University Hospital Zurich and Clinical Neuroscience Center, University of Zurich, Zurich, Switzerland.

Study Design: This is a retrospective cohort study.

Objective: The aim was to identify the risk factors for revision surgery within 2 years of patients undergoing primary adult spinal deformity (ASD) surgery.

Summary Of Background Data: Previous literature reports estimate 20% of patients undergoing thoracolumbar ASD correction undergo reoperation within 2 years. There is limited published data regarding specific risk factors for reoperation in ASD surgery in the short term and long term.

Methods: The authors queried the MarketScan database in order to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2015. Patient-level factors and revision risk were investigated during 2 years after primary ASD surgery. Patients under the age of 18 years and those with any prior history of trauma or tumor were excluded from this study.

Results: A total 7422 patients underwent ASD surgery during 2007-2015 in the data set. Revision rates were 13.1% at 90 days, 14.5% at 6 months, 16.7% at 1 year, and 19.3% at 2 years. In multivariate multiple logistic regression analysis, obesity [adjusted odds ratio (OR): 1.58, P<0.001] and tobacco use (adjusted OR: 1.38, P=0.0011) were associated with increased odds of reoperation within 2 years. Patients with a combined anterior-posterior approach had lower odds of reoperation compared with those with posterior only approach (adjusted OR: 0.66, P=0.0117).

Conclusions: Obesity and tobacco are associated with increased odds of revision surgery within 2 years of index ASD surgery. Male sex and combined surgical approach are associated with decreased odds of revision surgery.
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http://dx.doi.org/10.1097/BSD.0000000000001124DOI Listing
January 2021

Global adoption of robotic technology into neurosurgical practice and research.

Neurosurg Rev 2020 Nov 30. Epub 2020 Nov 30.

Machine Intelligence in Clinical Neuroscience (MICN) Lab, Department of Neurosurgery, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland.

Recent technological advancements have led to the development and implementation of robotic surgery in several specialties, including neurosurgery. Our aim was to carry out a worldwide survey among neurosurgeons to assess the adoption of and attitude toward robotic technology in the neurosurgical operating room and to identify factors associated with use of robotic technology. The online survey was made up of nine or ten compulsory questions and was distributed via the European Association of the Neurosurgical Societies (EANS) and the Congress of Neurological Surgeons (CNS) in February and March 2018. From a total of 7280 neurosurgeons who were sent the survey, we received 406 answers, corresponding to a response rate of 5.6%, mostly from Europe and North America. Overall, 197 neurosurgeons (48.5%) reported having used robotic technology in clinical practice. The highest rates of adoption of robotics were observed for Europe (54%) and North America (51%). Apart from geographical region, only age under 30, female gender, and absence of a non-academic setting were significantly associated with clinical use of robotics. The Mazor family (32%) and ROSA (26%) robots were most commonly reported among robot users. Our study provides a worldwide overview of neurosurgical adoption of robotic technology. Almost half of the surveyed neurosurgeons reported having clinical experience with at least one robotic system. Ongoing and future trials should aim to clarify superiority or non-inferiority of neurosurgical robotic applications and balance these potential benefits with considerations on acquisition and maintenance costs.
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http://dx.doi.org/10.1007/s10143-020-01445-6DOI Listing
November 2020

Medical malpractice in spine surgery: a review.

Neurosurg Focus 2020 11;49(5):E16

Medical malpractice is an important but often underappreciated topic within neurosurgery, particularly for surgeons in the early phases of practice. The practice of spinal neurosurgery involves substantial risk for litigation, as both the natural history of the conditions being treated and the operations being performed almost always carry the risk of permanent damage to the spinal cord or nerve roots, a cardiopulmonary event, death, or other dire outcomes. In this review, the authors discuss important topics related to medical malpractice in spine surgery, including tort reform, trends and frequency of litigation claims in spine surgery, wrong-level and wrong-site surgery, catastrophic outcomes including spinal cord injury and death, and ethical considerations.
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http://dx.doi.org/10.3171/2020.8.FOCUS20602DOI Listing
November 2020

Adverse Events and Bundled Costs after Cranial Neurosurgical Procedures: Validation of the LACE Index Across 40,431 Admissions and Development of the LACE-Cranial Index.

World Neurosurg 2021 Feb 28;146:e431-e451. Epub 2020 Oct 28.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA. Electronic address:

Objective: Anticipating postdischarge complications after neurosurgery remains difficult. The LACE index, based on 4 hospitalization descriptors, stratifies patients by risk of 30-day postdischarge adverse events but has not been validated in a procedure-specific manner in neurosurgery. Our study sought to explore the usefulness of the LACE index in a population undergoing cranial neurosurgery and to develop an enhanced model, LACE-Cranial.

Methods: The OptumClinformatics Database was used to identify cranial neurosurgery admissions (2004-2017). Procedures were grouped as trauma/hematoma/intracranial pressure, open vascular, functional/pain, skull base, tumor, or endovascular. Adverse events were defined as postdischarge death/readmission. LACE-Cranial was developed using a logistic regression framework incorporating an expanded feature set in addition to the original LACE components.

Results: A total of 40,431 admissions were included. Predictions of 30-day readmissions was best for skull base (area under the curve [AUC], 0.636) and tumor (AUC, 0.63) admissions but was generally poor. Predictive ability of 30-day mortality was best for functional/pain admissions (AUC, 0.957) and poorest for trauma/hematoma/intracranial pressure admissions (AUC, 0.613). Across procedure types except for functional/pain, a high-risk LACE score was associated with higher postdischarge bundled payment costs. Incorporating features identified to contribute independent predictive value, the LACE-Cranial model achieved procedure-specific 30-day mortality AUCs ranging from 0.904 to 0.98. Prediction of 30-day and 90-day readmissions was also improved, with tumor and skull base cases achieving 90-day readmission AUCs of 0.718 and 0.717, respectively.

Conclusions: Although the unmodified LACE index shows inconsistent classification performance, the enhanced LACE-Cranial model offers excellent prediction of short-term postdischarge mortality across procedure groups and significantly improved anticipation of short-term postdischarge readmissions.
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http://dx.doi.org/10.1016/j.wneu.2020.10.103DOI Listing
February 2021

Fostering reproducibility and generalizability in machine learning for clinical prediction modeling in spine surgery.

Spine J 2020 Oct 13. Epub 2020 Oct 13.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA. Electronic address:

As the use of machine learning algorithms in the development of clinical prediction models has increased, researchers are becoming more aware of the deleterious effects that stem from the lack of reporting standards. One of the most obvious consequences is the insufficient reproducibility found in current prediction models. In an attempt to characterize methods to improve reproducibility and to allow for better clinical performance, we utilize a previously proposed taxonomy that separates reproducibility into 3 components: technical, statistical, and conceptual reproducibility. By following this framework, we discuss common errors that lead to poor reproducibility, highlight the importance of generalizability when evaluating a ML model's performance, and provide suggestions to optimize generalizability to ensure adequate performance. These efforts are a necessity before such models are applied to patient care.
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http://dx.doi.org/10.1016/j.spinee.2020.10.006DOI Listing
October 2020

Predictive modeling of long-term opioid and benzodiazepine use after intradural tumor resection.

Spine J 2020 Oct 13. Epub 2020 Oct 13.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, United States. Electronic address:

Background Context: Despite increased awareness of the ongoing opioid epidemic, opioid and benzodiazepine use remain high after spine surgery. In particular, long-term co-prescription of opioids and benzodiazepines have been linked to high risk of overdose-associated death. Tumor patients represent a unique subset of spine surgery patients and few studies have attempted to develop predictive models to anticipate long-term opioid and benzodiazepine use after spinal tumor resection.

Methods: The IBM Watson Health MarketScan Database and Medicare Supplement were assessed to identify admissions for intradural tumor resection between 2007 and 2015. Adult patients were required to have at least 6 months of continuous preadmission baseline data and 12 months of continuous postdischarge follow-up. Primary outcomes were long-term opioid and benzodiazepine use, defined as at least 6 prescriptions within 12 months. Secondary outcomes were durations of opioid and benzodiazepine prescribing. Logistic regression models, with and without regularization, were trained on an 80% training sample and validated on the withheld 20%.

Results: A total of 1,942 patients were identified. The majority of tumors were extramedullary (74.8%) and benign (62.5%). A minority of patients received arthrodesis (9.2%) and most patients were discharged to home (79.1%). Factors associated with postdischarge opioid use duration include tumor malignancy (vs benign, B=19.8 prescribed-days/year, 95% confidence interval [CI] 1.1-38.5) and intramedullary compartment (vs extramedullary, B=18.1 prescribed-days/year, 95% CI 3.3-32.9). Pre- and perioperative use of prescribed nonsteroidal anti-inflammatory drugs and gabapentin/pregabalin were associated with shorter and longer duration opioid use, respectively. History of opioid and history of benzodiazepine use were both associated with increased postdischarge opioid and benzodiazepine use. Intramedullary location was associated with longer duration postdischarge benzodiazepine use (B=10.3 prescribed-days/year, 95% CI 1.5-19.1). Among assessed models, elastic net regularization demonstrated best predictive performance in the withheld validation cohort when assessing both long-term opioid use (area under curve [AUC]=0.748) and long-term benzodiazepine use (AUC=0.704). Applying our model to the validation set, patients scored as low-risk demonstrated a 4.8% and 2.4% risk of long-term opioid and benzodiazepine use, respectively, compared to 35.2% and 11.1% of high-risk patients.

Conclusions: We developed and validated a parsimonious, predictive model to anticipate long-term opioid and benzodiazepine use early after intradural tumor resection, providing physicians opportunities to consider alternative pain management strategies.
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http://dx.doi.org/10.1016/j.spinee.2020.10.010DOI Listing
October 2020

Evaluating the Impact of Spinal Osteotomy on Surgical Outcomes of Thoracolumbar Deformity Correction.

World Neurosurg 2020 Dec 18;144:e774-e779. Epub 2020 Sep 18.

Stanford Neurosurgical Artificial Intelligence and Machine Learning Laboratory, Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA. Electronic address:

Background: In cases of adult spinal deformity (ASD) with severe sagittal malalignment, the use of osteotomies may be necessary in addition to posterior fusion. However, few data exist describing the impact of osteotomies on complications and quality outcomes during ASD surgery.

Methods: We queried the MarketScan database to identify patients who underwent ASD surgery in 2007-2016. Patients were stratified according to whether or not an osteotomy was used in the index operation. Propensity score matching was used to mitigate intergroup differences between osteotomy and nonosteotomy groups. Patients <18 years old and patients with any prior history of trauma or tumor were excluded from the study.

Results: Of 7423 patients who met the inclusion criteria of this study, 2700 (36.4%) received an osteotomy. After propensity score matching, baseline comorbidities and approach type were similar between cohorts. The overall 90-day complication rate was 43.2% in the nonosteotomy group and 52.8% in the osteotomy group (P < 0.0001). The osteotomy cohort also had significantly higher rates of revision surgeries through 2 years (21.1% vs. 18.0%, P < 0.05) following index surgery. Patients who received a 3-column osteotomy had the highest procedural payments, costing $155,885 through 90 days and $167,161 through 1 year following surgery.

Conclusions: This analysis confirms high costs and complication, readmission, and reoperation rates until 2 years after ASD surgery in general, which are even higher in cases where an osteotomy is required. Future research should explore strategies for optimizing patient outcomes following osteotomy.
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http://dx.doi.org/10.1016/j.wneu.2020.09.072DOI Listing
December 2020

A Comparative Analysis of Patients Undergoing Fusion for Adult Cervical Deformity by Approach Type.

Global Spine J 2020 Apr 13:2192568220915717. Epub 2020 Apr 13.

Stanford University, Stanford, CA, USA.

Study Design: Retrospective cohort study.

Objective: To provide insight into postoperative complications, short-term quality outcomes, and costs of the surgical approaches of adult cervical deformity (ACD).

Methods: A national database was queried from 2007 to 2016 to identify patients who underwent cervical fusion for ACD. Patients were stratified by approach type-anterior, posterior, or circumferential. Patients undergoing anterior and posterior approach surgeries were additionally compared using propensity score matching.

Results: A total of 6575 patients underwent multilevel cervical fusion for ACD correction. Circumferential fusion had the highest postoperative complication rate (46.9% vs posterior: 36.7% vs anterior: 18.5%, < .0001). Anterior fusion patients more commonly required reoperation compared with posterior fusion patients ( < .0001), and 90-day readmission rate was highest for patients undergoing circumferential fusion ( < .0001). After propensity score matching, the complication rate remained higher in the posterior, as compared to the anterior fusion group ( < .0001). Readmission rate also remained higher in the posterior fusion group; however, anterior fusion patients were more likely to require reoperation. At index hospitalization, posterior fusion led to 1.5× higher costs, and total payments at 90 days were 1.6× higher than their anterior fusion counterparts.

Conclusion: Patients who undergo posterior fusion for ACD have higher complication rates, readmission rates, and higher cost burden than patients who undergo anterior fusion; however, posterior correction of ACD is associated with a lower rate of reoperation.
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http://dx.doi.org/10.1177/2192568220915717DOI Listing
April 2020

Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery.

Global Spine J 2021 Apr 25;11(3):345-350. Epub 2020 Feb 25.

6429Stanford University School of Medicine, Stanford, CA, USA.

Study Design: This is a retrospective cohort study using a nationally representative administrative database.

Objective: To identify the impact of obesity on postoperative outcomes in patients undergoing thoracolumbar adult spinal deformity (ASD) surgery.

Background: The obesity rate in the United States remains staggering, with approximately one-third of all Americans being overweight or obese. However, the impact of elevated body mass index on spine surgery outcomes remains unclear.

Methods: We queried the MarketScan database to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2016. Patients were then stratified by whether or not they were diagnosed as obese at index surgical admission. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between obese and nonobese patients. Patients <18 years and those with any prior history of trauma or tumor were excluded from this study. Baseline demographics and comorbidities, postoperative complication rates, and short- and long-term reoperation rates were determined.

Results: A total of 7423 patients met the inclusion criteria of this study, of whom 597 (8.0%) were obese. Initially, patients with obesity had a higher 90-day postoperative complication rate than nonobese patients (46.1% vs 40.8%, < .05); however, this difference did not remain after PSM. Revision surgery rates after 2 years were similar across the 2 groups following primary surgery (obese, 21.4%, vs nonobese, 22.0%; = .7588). Health care use occurred at a higher rate among obese patients through 2 years of long-term follow-up (obese, $152 930, vs nonobese, $140 550; < .05).

Conclusion: Patients diagnosed with obesity who underwent ASD surgery did not demonstrate increased rates of complications, reoperations, or readmissions. However, overall health care use through 2 years of follow-up after index surgery was higher in the obesity cohort.
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http://dx.doi.org/10.1177/2192568220904341DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8013946PMC
April 2021

Timing of Adjuvant Radiation Therapy and Risk of Wound-Related Complications Among Patients With Spinal Metastatic Disease.

Global Spine J 2021 Jan 22;11(1):44-49. Epub 2019 Nov 22.

6429Stanford University School of Medicine, Stanford, CA, USA.

Study Design: This was an epidemiological study using national administrative data from the MarketScan database.

Objective: To investigate the impact of early versus delayed adjuvant radiotherapy (RT) on wound healing following surgical resection for spinal metastatic disease.

Methods: We queried the MarketScan database (2007-2016), identifying patients with a diagnosis of spinal metastasis who also underwent RT within 8 weeks of surgery. Patients were categorized into "Early RT" if they received RT within 4 weeks of surgery and as "Late RT" if they received RT between 4 and 8 weeks after surgery. Descriptive statistics and hypothesis testing were used to compare baseline characteristics and wound complication outcomes.

Results: A total of 540 patients met the inclusion criteria: 307 (56.9%) received RT within 4 weeks (Early RT) and 233 (43.1%) received RT within 4 to 8 weeks (Late RT) of surgery. Mean days to RT for the Early RT cohort was 18.5 (SD, 6.9) and 39.7 (SD, 7.6) for the Late RT cohort. In a 90-day surveillance period, n = 9 (2.9%) of Early RT and n = 8 (3.4%) of Late RT patients developed wound complications ( = .574).

Conclusions: When comparing patients who received RT early versus delayed following surgery, there were no significant differences in the rates of wound complications. Further prospective studies should aim to identify optimal patient criteria for early postoperative RT for spinal metastases.
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http://dx.doi.org/10.1177/2192568219889363DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7734271PMC
January 2021

Opioid Prescribing Patterns for Low Back Pain Among Commercially Insured Children.

Spine (Phila Pa 1976) 2020 Nov;45(21):E1365-E1366

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA.

: Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003657DOI Listing
November 2020

Opioid Use in Adults With Low Back or Lower Extremity Pain Who Undergo Spine Surgical Treatment Within 1 Year of Diagnosis.

Spine (Phila Pa 1976) 2020 Dec;45(24):1725-1735

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA.

Study Design: Retrospective longitudinal cohort.

Objective: We investigated opioid prescribing patterns amongst adults in the United States diagnosed with low back or lower extremity pain (LBP/LEP) who underwent spine surgery.

Summary Of Background Data: Opioid-based treatment of LBP/LEP and postsurgical pain has separately been associated with chronic opioid use, but a combined and large-scale cohort study is missing.

Methods: This study utilizes commercial inpatient, outpatient, and pharmaceutical insurance claims. Between 2008 and 2015, patients without previous prescription opioids with a new diagnosis of LBP/LEP who underwent surgery within 1 year after diagnosis were enrolled. Opioid prescribing patterns after LBP/LEP diagnosis and after surgery were evaluated. All patients had 1-year postoperative follow-up. Low and high frequency (6 or more refills in 12 months) opioid prescription groups were identified.

Results: A total of 25,506 patients without previous prescription opioids were diagnosed with LBP/LEP and underwent surgery within 1 year of diagnosis. After LBP/LEP diagnosis, 18,219 (71.4%) were prescribed opioids, whereas 7287 (28.6%) were not. After surgery, 2952 (11.6%) were prescribed opioids with high frequency and 22,554 (88.4%) with low frequency. Among patients prescribed opioids before surgery, those with high-frequency prescriptions were more likely to continue this pattern postoperatively than those with low frequency prescriptions preoperatively (OR 2.15, 95% CI 1.97-2.34). For those prescribed opioids preoperatively, average daily morphine milligram equivalent (MME) decreased after surgery (by 2.62 in decompression alone cohort and 0.25 in arthrodesis cohort, P < 0.001). Postoperative low-frequency patients were more likely than high-frequency patients to discontinue opioids one-year after surgery (OR 3.78, 95% CI 3.59-3.99). Postoperative high-frequency patients incurred higher cost than low-frequency patients. Postoperative high-frequency prescribing varied widely across states (4.3%-20%).

Conclusion: A stepwise association exists between opioid use after LEP or LBP diagnosis and frequency and duration of opioid prescriptions after surgery. Simultaneously, the strength of prescriptions as measured by MME decreased following surgery.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003663DOI Listing
December 2020

Machine learning in neurosurgery: a global survey.

Acta Neurochir (Wien) 2020 12 18;162(12):3081-3091. Epub 2020 Aug 18.

Machine Intelligence in Clinical Neuroscience (MICN) Lab, Department of Neurosurgery, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland.

Background: Recent technological advances have led to the development and implementation of machine learning (ML) in various disciplines, including neurosurgery. Our goal was to conduct a comprehensive survey of neurosurgeons to assess the acceptance of and attitudes toward ML in neurosurgical practice and to identify factors associated with its use.

Methods: The online survey consisted of nine or ten mandatory questions and was distributed in February and March 2019 through the European Association of Neurosurgical Societies (EANS) and the Congress of Neurosurgeons (CNS).

Results: Out of 7280 neurosurgeons who received the survey, we received 362 responses, with a response rate of 5%, mainly in Europe and North America. In total, 103 neurosurgeons (28.5%) reported using ML in their clinical practice, and 31.1% in research. Adoption rates of ML were relatively evenly distributed, with 25.6% for North America, 30.9% for Europe, 33.3% for Latin America and the Middle East, 44.4% for Asia and Pacific and 100% for Africa with only two responses. No predictors of clinical ML use were identified, although academic settings and subspecialties neuro-oncology, functional, trauma and epilepsy predicted use of ML in research. The most common applications were for predicting outcomes and complications, as well as interpretation of imaging.

Conclusions: This report provides a global overview of the neurosurgical applications of ML. A relevant proportion of the surveyed neurosurgeons reported clinical experience with ML algorithms. Future studies should aim to clarify the role and potential benefits of ML in neurosurgery and to reconcile these potential advantages with bioethical considerations.
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http://dx.doi.org/10.1007/s00701-020-04532-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7593280PMC
December 2020

Association Between Physician Industry Payments and Cost of Anterior Cervical Discectomy and Fusion in Medicare Beneficiaries.

World Neurosurg 2020 11 10;143:e574-e580. Epub 2020 Aug 10.

Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA; Center for Healthcare Value, University of California, San Francisco, California, USA; Department of Neurological Surgery, University of California, San Francisco, California, USA; Department of Neurological Surgery, Stanford University, Palo Alto, California, USA. Electronic address:

Background: Neurosurgical spine specialists receive considerable amounts of industry support that may impact the cost of care. The aim of this study was to evaluate the association between industry payments received by spine surgeons and the total hospital and operating room (OR) costs of an anterior cervical discectomy and fusion (ACDF) procedure among Medicare beneficiaries.

Methods: All ACDF cases were identified among the Medicare carrier files from January 1, 2013, to December 31, 2014, and matched to the Medicare inpatient baseline file. The total hospital and OR charges were obtained for these cases. Charges were converted to cost using year-specific cost-to-charge ratios. Surgeons were identified among the Open Payments database, which is used to quantify industry support. Analyses were performed to examine the association between industry payments received and ACDF costs.

Results: Matching resulting in the inclusion of 2209 ACDF claims from 2013-2014. In 2013 and 2014, the mean total cost for an ACDF was $21,798 and $21,008, respectively; mean OR cost was $5878 and $6064, respectively. Mann-Whitney U test demonstrated no significant differences in the mean total or OR cost for an ACDF based on quartile of general industry payment received (P = 0.21 and P = 0.54), and linear regression found no association between industry general payments, research support, or investments on the total hospital cost (P = 0.41, P = 0.13, and P = 0.25, respectively), or OR cost for an ACDF (P = 0.35, P = 0.24, and P = 0.40, respectively).

Conclusions: This study suggests that spine surgeons performing ACDF surgeries may receive industry support without impacting the cost of care.
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http://dx.doi.org/10.1016/j.wneu.2020.08.023DOI Listing
November 2020

Complications, Costs, and Quality Outcomes of Patients Undergoing Cervical Deformity Surgery With Intraoperative BMP Use.

Spine (Phila Pa 1976) 2020 Nov;45(22):1553-1558

Neurosurgery AI Lab & Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA.

Study Design: An epidemiological study using national administrative data from the MarketScan database.

Objective: The aim of this study was to identify the impact of bone morphogenetic protein (BMP) on postoperative outcomes in patients undergoing adult cervical deformity (ACD) surgery.

Summary Of Background Data: BMP has been shown to stimulate bone growth and improve fusion rates in spine surgery. However, the impact of BMP on reoperation rates and postoperative complication rate is controversial.

Methods: We queried the MarketScan database to identify patients who underwent ACD surgery from 2007 to 2015. Patients were stratified by BMP use in the index operation. Patients <18 years and those with any history of tumor or trauma were excluded. Baseline demographics and comorbidities, postoperative complication rates, and reoperation rates were analyzed.

Results: A total of 13,549 patients underwent primary ACD surgery, of which 1155 (8.5%) had intraoperative BMP use. The overall 90-day complication rate was 27.6% in the non-BMP cohort and 31.1% in the BMP cohort (P < 0.05). Patients in the BMP cohort had longer average length of stay (4.0 days vs. 3.7 days, P < 0.05) but lower revision surgery rates at 90 days (14.5% vs. 28.3%, P < 0.05), 6 months (14.9% vs. 28.6%, P < 0.05), 1 year (15.7% vs. 29.2%, P < 0.05), and 2 years (16.5% vs. 29.9%, P < 0.05) postoperatively. BMP use was associated with higher payments throughout the 2-year follow-up period ($107,975 vs. $97,620, P < 0.05). When controlling for baseline group differences, BMP use independently increased the odds of postoperative complication (odds ratio [OR] 1.22, 95% confidence interval [CI] 1.1-1.4) and reduced the odds of reoperation throughout 2 years of follow-up (OR 0.49, 95% CI 0.4-0.6).

Conclusion: Intraoperative BMP use has benefits for fusion integrity in ACD surgery but is associated with increased postoperative complication rate. Spine surgeons should weigh these benefits and drawbacks to identify optimal candidates for BMP use in ACD surgery.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003629DOI Listing
November 2020

Predictors of 2-year reoperation in Medicare patients undergoing primary thoracolumbar deformity surgery.

J Neurosurg Spine 2020 Jul 24:1-5. Epub 2020 Jul 24.

1Neurosurgery AI Lab & Department of Neurosurgery, Stanford University School of Medicine, Stanford, California; and.

Objective: This was a retrospective cohort study in which the authors used a nationally representative administrative database. Their goal was to identify the risk factors for reoperation in Medicare patients undergoing primary thoracolumbar adult spinal deformity (ASD) surgery. Previous literature reports estimate that 20% of patients undergoing thoracolumbar ASD correction undergo revision surgery within 2 years. Most published data discuss risk factors for revision surgery in the general population, but these have not been explored specifically in the Medicare population.

Methods: Using the MarketScan Medicare Supplemental database, the authors identified patients who were diagnosed with a spinal deformity and underwent ASD surgery between 2007 and 2015. The interactions of patient demographics, surgical factors, and medical factors with revision surgery were investigated during the 2 years following primary ASD surgery. The authors excluded patients without Medicare insurance and those with any prior history of trauma or tumor.

Results: Included in the data set were 2564 patients enrolled in Medicare who underwent ASD surgery between 2007 and 2015. The mean age at diagnosis with spinal deformity was 71.5 years. A majority of patients (68.5%) were female. Within 2 years of follow-up, 661 (25.8%) patients underwent reoperation. Preoperative osteoporosis (OR 1.58, p < 0.0001), congestive heart failure (OR 1.35, p = 0.0161), and paraplegia (OR 2.41, p < 0.0001) independently increased odds of revision surgery. The use of intraoperative bone morphogenetic protein was protective against reoperation (OR 0.71, p = 0.0371). Among 90-day postoperative complications, a wound complication was the strongest predictor of undergoing repeat surgery (OR 2.85, p = 0.0061). The development of a pulmonary embolism also increased the odds of repeat surgery (OR 1.84, p = 0.0435).

Conclusions: Approximately one-quarter of Medicare patients with ASD who underwent surgery required an additional spinal surgery within 2 years. Baseline comorbidities such as osteoporosis, congestive heart failure, and paraplegia, as well as short-term complications such as pulmonary embolism and wound complications significantly increased the odds of repeat surgery.
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http://dx.doi.org/10.3171/2020.5.SPINE191425DOI Listing
July 2020

Commentary: Predictors of the Best Outcomes Following Minimally Invasive Surgery for Grade 1 Degenerative Lumbar Spondylolisthesis.

Neurosurgery 2020 Jul 20. Epub 2020 Jul 20.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, California.

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http://dx.doi.org/10.1093/neuros/nyaa288DOI Listing
July 2020

Single- versus dual-attending strategy for spinal deformity surgery: 2-year experience and systematic review of the literature.

J Neurosurg Spine 2020 Jul 10:1-12. Epub 2020 Jul 10.

2Neurosurgery, Stanford University Hospitals and Clinics, Stanford, California.

Objective: Adult spinal deformity (ASD) surgery is complex and associated with high morbidity and complication rates. There is growing evidence in the literature for the beneficial effects of an approach to surgery in which two attending physicians rather than a single attending physician perform surgery for and oversee the surgical care of a single patient in a dual-attending care model. The authors developed a dual-attending care collaboration in August 2017 in which a neurosurgeon and an orthopedic surgeon mutually operated on patients with ASD.

Methods: The authors recorded data for 2 years of experience with ASD patients operated on by dual attending surgeons. Analyses included estimated blood loss (EBL), transfusions, length of stay (LOS), discharge disposition, complication rates, emergency room visits and readmissions, subjective health status improvement, and disability (Oswestry Disability Index [ODI] score) and pain (visual analog scale [VAS] score) at last follow-up. In addition, the pertinent literature for dual-attending spinal deformity correction was systematically reviewed.

Results: The study group comprised 19 of 254 (7.5%) consecutively operated patients who underwent thoracolumbar fusion during the period from January 2017 to June 2019 (68.4% female; mean patient age 65.1 years, ODI score 44.5, VAS pain score 6.8). The study patients were matched by age, sex, anesthesia risk, BMI, smoking status, ODI score, VAS pain score, prior spine surgeries, and basic operative characteristics (type of interbody implants, instrumented segments, pelvic fixation) to 19 control patients (all p > 0.05). There was a trend toward less EBL (mean 763 vs 1524 ml, p = 0.059), fewer intraoperative red blood cell transfusions (mean 0.5 vs 2.3, p = 0.079), and fewer 90-day readmissions (0% vs 15.8%, p = 0.071) in the dual-attending group. LOS and discharge disposition were similar, as were the rates of any < 30-day postsurgery complications, < 90-day postsurgery emergency room visits, and reoperations, and ODI and VAS pain scores at last follow-up (all p > 0.05). At last follow-up, 94.7% vs 68.4% of patients in the dual- versus single-attending group stated their health status had improved (p = 0.036). In the authors' literature search of prior articles on spinal deformity correction, 5 of 8 (62.5%) articles reported lower EBL and 6 of 8 (75%) articles reported significantly lower operation duration in dual-attending cases. The literature contained differing results with regard to complication- or reoperation-sparing effects associated with dual-attending cases. Similar clinical outcomes of dual- versus single-attending cases were reported.

Conclusions: Establishing a dual-attending care management platform for ASD correction was feasible at the authors' institution. Results of the use of a dual-attending strategy at the authors' institution were favorable. Positive safety and outcome profiles were found in articles on this topic identified by a systematic literature review.
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http://dx.doi.org/10.3171/2020.3.SPINE2016DOI Listing
July 2020

Cervical osteochondroma: surgical planning.

Spinal Cord Ser Cases 2020 05 28;6(1):44. Epub 2020 May 28.

Department of Neurological Surgery, Kaiser Permanente Orange County, 3460 E La Palma Ave, Anaheim, CA, 92806, USA.

Introduction: Osteochondromas are benign bone tumors which occur as solitary lesions or as part of the syndrome multiple hereditary exostoses. While most osteochondromas occur in the appendicular skeleton, they can also occur in the spine. Most lesions are asymptomatic however some may encroach on the spinal cord or the nerve roots causing neurological symptoms. While most patients with osteochondromas undergo laminectomy without fusion, laminectomy with fusion is indicated in appropriately selected cases of spinal decompression.

Case Presentation: We present a case of a 32-year-old male with history of multiple hereditary exostoses who presented with symptoms of bilateral upper extremity numbness and complaints of gait imbalance and multiple falls. He reported rapid progression of his symptoms during the 10 days before presentation. Computed tomography of the cervical spine revealed a lobulated bony tumor along the inner margin of the cervical 4 lamina. He underwent cervical 3 and 4 laminectomies, partial cervical 2 and 5 laminectomies and cervical 3-5 mass screw placement. Pathology was consistent with osteochondroma. The patient's symptoms had markedly improved at follow-up.

Conclusion: According to our literature review, osteochondromas most commonly occur at cervical 2 and cervical 5. We present a case of an osteochondroma at a less common level, cervical 4. While most osteochondromas are addressed with laminectomy without arthrodesis, the decision of whether arthrodesis is necessary should be considered in all patients with osteochondroma as with any cervical decompression.
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http://dx.doi.org/10.1038/s41394-020-0292-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7256042PMC
May 2020

A predictive-modeling based screening tool for prolonged opioid use after surgical management of low back and lower extremity pain.

Spine J 2020 08 20;20(8):1184-1195. Epub 2020 May 20.

Department of Neurosurgery, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA. Electronic address:

Background Context: Outpatient postoperative pain management in spine patients, specifically involving the use of opioids, demonstrates significant variability.

Purpose: Using preoperative risk factors and 30-day postoperative opioid prescribing patterns, we developed models for predicting long-term opioid use in patients after elective spine surgery.

Study Design/setting: This retrospective cohort study utilizes inpatient, outpatient, and pharmaceutical data from MarketScan databases (Truven Health).

Patient Sample: In all, 19,317 patients who were newly diagnosed with low back or lower extremity pain (LBP or LEP) between 2008 and 2015 and underwent thoracic or lumbar surgery within 1 year after diagnosis were enrolled. Some patients initiated opioids after diagnosis but all patients were opioid-naïve before the diagnosis.

Outcome Measures: Long-term opioid use was defined as filling ≥180 days of opioids within one year after surgery.

Methods: Using demographic variables, medical and psychiatric comorbidities, preoperative opioid use, and 30-day postoperative opioid use, we generated seven models on 80% of the dataset and tested the models on the remaining 20%. We used three regression-based models (full logistic regression, stepwise logistic regression, least absolute shrinkage and selection operator), support vector machine, two tree-based models (random forest, stochastic gradient boosting), and time-varying convolutional neural network. Area under the curve (AUC), Brier index, sensitivity, and calibration curves were used to assess the discrimination and calibration of the models.

Results: We identified 903 (4.6%) of patients who met criteria for long-term opioid use. The regression-based models demonstrated the highest AUC, ranging from 0.835 to 0.847, and relatively high sensitivities, predicting between 74.9% and 76.5% of the long-term opioid use patients in the test dataset. The three strongest positive predictors of long-term opioid use were high preoperative opioid use (OR 2.70; 95% confidence interval [CI] 2.27-3.22), number of days with active opioid prescription between postoperative days 15 to 30 (OR 1.10; 95%CI 1.07-1.12), and number of dosage increases between postoperative day 15 to 30 (OR 1.71, 95%CI 1.41-2.08). The strongest negative predictors were number of dosage decreases in the 30-day postoperative period.

Conclusions: We evaluated several predictive models for postoperative long-term opioid use in a large cohort of patients with LBP or LEP who underwent surgery. A regression-based model with high sensitivity and AUC is provided online to screen patients for high risk of long-term opioid use based on preoperative risk factors and opioid prescription patterns in the first 30 days after surgery. It is hoped that this work will improve identification of patients at high risk of prolonged opioid use and enable early intervention and counseling.
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http://dx.doi.org/10.1016/j.spinee.2020.05.098DOI Listing
August 2020

Conventional versus stereotactic image guided pedicle screw placement during spinal deformity correction: a retrospective propensity score-matched study of a national longitudinal database.

Int J Neurosci 2020 Jun 1:1-9. Epub 2020 Jun 1.

Department of Neurosurgery, Stanford University, Stanford, CA, USA.

To compare complications, readmissions, revisions, and payments between navigated and conventional pedicle screw fixation for treatment of spine deformity. The Thomson Reuters MarketScan national longitudinal database was used to identify patients undergoing osteotomy, posterior instrumentation, and fusion for treatment of spinal deformity with or without image-guided navigation between 2007-2016. Conventional and navigated groups were propensity-matched (1:1) to normalize differences between demographics, comorbidities, and surgical characteristics. Clinical outcomes and charges were compared between matched groups using bivariate analyses. A total of 4,604 patients were identified as having undergone deformity correction, of which 286 (6.2%) were navigated. Propensity-matching resulted in a total of 572 well-matched patients for subsequent analyses, of which half were navigated. Rate of mechanical instrumentation-related complications was found to be significantly lower for navigated procedures ( = 0.0371). Navigation was also associated with lower rates of 90-day unplanned readmissions ( = 0.0295), as well as 30- and 90-day postoperative revisions (30-day:  = 0.0304, 90-day:  = 0.0059). Hospital, physician, and total payments favored the conventional group for initial admission ( = 0.0481, 0.0001, 0.0019, respectively); however, when taking into account costs of readmissions, hospital payments became insignificantly different between the two groups. Procedures involving image-guided navigation resulted in decreased instrumentation-related complications, unplanned readmissions, and postoperative revisions, highlighting its potential utility for the treatment of spine deformity. Future advances in navigation technologies and methodologies can continue to improve clinical outcomes, decrease costs, and facilitate widespread adoption of navigation for deformity correction.
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http://dx.doi.org/10.1080/00207454.2020.1763343DOI Listing
June 2020

Objective activity tracking in spine surgery: a prospective feasibility study with a low-cost consumer grade wearable accelerometer.

Sci Rep 2020 03 18;10(1):4939. Epub 2020 Mar 18.

Department of Neurosurgery, Stanford University Hospitals and Clinics, Stanford, California, USA.

Patient-reported outcome measures (PROMs) are commonly used to estimate disability of patients with spinal degenerative disease. Emerging technological advances present an opportunity to provide objective measurements of activity. In a prospective, observational study we utilized a low-cost consumer grade wearable accelerometer (LCA) to determine patient activity (steps per day) preoperatively (baseline) and up to one year (Y1) after cervical and lumbar spine surgery. We studied 30 patients (46.7% male; mean age 57 years; 70% Caucasian) with a baseline activity level of 5624 steps per day. The activity level decreased by 71% in the 1 postoperative week (p < 0.001) and remained 37% lower in the 2 (p < 0.001) and 23% lower in the 4 week (p = 0.015). At no time point until Y1 did patients increase their activity level, compared to baseline. Activity was greater in patients with cervical, as compared to patients with lumbar spine disease. Age, sex, ethnic group, anesthesia risk score and fusion were variables associated with activity. There was no correlation between activity and PROMs, but a strong correlation with depression. Determining activity using LCAs provides real-time and longitudinal information about patient mobility and return of function. Recovery took place over the first eight postoperative weeks, with subtle improvement afterwards.
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http://dx.doi.org/10.1038/s41598-020-61893-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7080733PMC
March 2020

Costs and Complications Associated With Resection of Supratentorial Tumors With and Without the Operative Microscope in the United States.

World Neurosurg 2020 06 30;138:e607-e619. Epub 2020 Mar 30.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, California.

Background: The operative microscope, a commonly used tool in neurosurgery, is critical in many supratentorial tumor cases. However, use of operating microscope for supratentorial tumor varies by surgeon.

Objectives: To assess complication rates, readmissions, and costs associated with operative microscope use in supratentorial resections.

Methods: A retrospective analysis was conducted using a national administrative database to identify patients with glioma or brain metastases who underwent supratentorial resection between 2007 and 2016. Univariate and multivariate analyses were used to assess 30-day complications, readmissions, and costs between patients who underwent resection with and without use of microscope.

Results: The cohort included 12,058 glioma patients and 5433 metastasis patients. Rates of microscope use varied by state from 19.0% to 68.6%. Microscope use was associated with $5228.90 in additional costs of index hospitalization among glioma patients (P <0.001), and $2824.00 among metastasis patients (P <0.001). Rates of intraoperative cerebral edema were lower among the microscope cohort than among the nonmicroscope cohort (P <0.027). Microscope use was associated with a slight reduction in 30-day rates of neurological complications (14.7% vs. 16.7%, P = 0.048), specifically in nonspecific cerebrovascular complications. There were no differences in rates of other complications, readmissions, or 30-day postoperative costs.

Conclusions: Use of operative microscope for supratentorial resections varies by state and is associated with higher cost of surgery. Microscope use may be associated with lower rates of intraoperative cerebral edema and some cerebrovascular complications, but is not associated with significant differences in other complications, readmissions, or 30-day costs.
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http://dx.doi.org/10.1016/j.wneu.2020.03.021DOI Listing
June 2020

Adult Spinal Deformity Surgery in Patients With Movement Disorders: A Propensity-matched Analysis of Outcomes and Cost.

Spine (Phila Pa 1976) 2020 Mar;45(5):E288-E295

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA.

Study Design: This was a retrospective study using national administrative data from the MarketScan database.

Objective: To investigate the complication rates, quality outcomes, and costs in a nationwide cohort of patients with movement disorders (MD) who undergo spinal deformity surgery.

Summary Of Background Data: Patients with MD often present with spinal deformities, but their tolerance for surgical intervention is unknown.

Methods: The MarketScan administrative claims database was queried to identify adult patients with MD who underwent spinal deformity surgery. A propensity-score match was conducted to create two uniform cohorts and mitigate interpopulation confounders. Perioperative complication rates, 90-day postoperative outcomes, and total costs were compared between patients with MD and controls.

Results: A total of 316 patients with MD (1.7%) were identified from the 18,970 undergoing spinal deformity surgery. The complication rate for MD patients was 44.6% and for the controls 35.6% (P = 0.009). The two most common perioperative complications were more likely to occur in MD patients, acute-posthemorrhagic anemia (26.9% vs. 20.8%, P < 0.05) and deficiency anemia (15.5% vs. 8.5%, P < 0.05). At 90 days, MD patients were more likely to be readmitted (17.4% vs. 13.2%, P < 0.05) and have a higher total cost ($94,672 vs. $85,190, P < 0.05). After propensity-score match, the overall complication rate remained higher in the MD group (44.6% vs. 37.6%, P < 0.05). 90-day readmissions and costs also remained significantly higher in the MD cohort. Multivariate modeling revealed MD was an independent predictor of postoperative complication and inpatient readmission. Subgroup analysis revealed that Parkinson disease was an independent predictor of inpatient readmission, reoperation, and increased length of stay.

Conclusion: Patients with MD who undergo spinal deformity surgery may be at risk of higher rate of perioperative complications and 90-day readmissions compared with patients without these disorders.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003251DOI Listing
March 2020

Evaluating Shunt Survival Following Ventriculoperitoneal Shunting with and without Stereotactic Navigation in Previously Shunt-Naïve Patients.

World Neurosurg 2020 Apr 26;136:e671-e682. Epub 2020 Jan 26.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, California. Electronic address:

Background: Ventriculoperitoneal shunts are used to alleviate elevated intracranial pressure due to either hydrocephalus or idiopathic intracranial hypertension; however, shunt failure is a significant neurosurgical problem. Despite increases in intraoperative stereotactic navigation usage over the past decade, its effect on shunt survival remains unclear.

Methods: Shunt-naïve pediatric and adult patients receiving ventriculoperitoneal shunting between 2007 and 2015 were identified in a national administrative database. Multivariable logistic and Cox regressions were used to evaluate factors affecting stereotaxy usage and shunt survival. Matched cohorts were generated by propensity score balancing.

Results: Of 9677 patients identified, 932 received image-guided shunt placement. Total shunt failure rate was not associated with stereotaxy use (20.3% with stereotaxy vs. 19.4% without, P = 0.4602). In the matched setting, shunt survival was not extended by use of image guidance during placement (hazard ratio = 1.134, 95% confidence interval 0.923-1.393). Late shunt failures (defined as failures occurring at least 30 days after shunt placement) caused by infection occurred more frequently in the stereotaxy cohort (hazard ratio = 2.207, 95% confidence interval 1.115-4.366), whereas late shunt failures attributable to mechanical shunt failure were more common in the nonstereotaxy cohort (hazard ratio = 1.406, 95% confidence interval 1.002-1.973).

Conclusions: Our findings suggest stereotaxy use during ventriculoperitoneal shunt placement does not affect shunt survival. Late shunt failures caused by infection occurred more frequently in the stereotaxy cohort, whereas late failures caused by mechanical shunt malfunction were more commonly encountered in the nonstereotaxy cohort.
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http://dx.doi.org/10.1016/j.wneu.2020.01.138DOI Listing
April 2020

Outcomes and Costs Following Ommaya Placement with Thrombocytopenia Among U.S. Patients with Cancer.

World Neurosurg 2020 Mar 19;135:e548-e561. Epub 2019 Dec 19.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, U.S.A.

Background: Placement of Ommaya reservoirs for the administration of intrathecal chemotherapy may be complicated by comorbid thrombocytopenia among patients with hematologic or leptomeningeal disease. Aggregated data on risks of Ommaya placement among thrombocytopenic patients are lacking. This study assesses complications, revision rates, and costs associated with Ommaya placement among patients with thrombocytopenia in a large population sample.

Methods: Using a national administrative database, this retrospective study identifies a cohort of adult patients with cancer who underwent Ommaya placement between 2007 and 2016. Preoperative thrombocytopenia was defined as diagnosis of secondary thrombocytopenia, bleeding event, procedure to control bleeding, or platelet transfusion, within 30 days before index admission. Univariate and multivariate analyses were performed to assess costs, 30-day complications, readmissions, and revisions among patients with and without preoperative thrombocytopenia.

Results: The analytic cohort included 1652 patients, of whom 29.3% met criteria for preoperative thrombocytopenia. In-hospital mortality rates were 7.7% among patients thrombocytopenia with versus 1.2% among patients without thrombocytopenia (P < 0.001). Preoperative thrombocytopenia was associated with 14.5 times greater hazard of intracranial hemorrhage within 30 days following Ommaya placement, occurring in 25.6% versus 2.0% of patients with and without thrombocytopenia, respectively (P < 0.014). Revision rates did not differ significantly between patients with and without thrombocytopenia. Thrombocytopenia was associated with longer length of stay (7.4 vs. 13.9 days, P < 0.001) and additional $10,000 per patient in costs of index hospitalization (P < 0.001).

Conclusions: This is the largest study to date documenting costs and complication rates of Ommaya placement in patients with and without thrombocytopenia.
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http://dx.doi.org/10.1016/j.wneu.2019.12.063DOI Listing
March 2020

Randomized Controlled Trials in Functional Neurosurgery-Association of Device Approval Status and Trial Quality.

Neuromodulation 2020 Jun 11;23(4):496-501. Epub 2019 Dec 11.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.

Introduction: Randomized controlled trials (RCTs) have been critical in evaluating the safety and efficacy of functional neurosurgery interventions. Given this, we sought to systematically assess the quality of functional neurosurgery RCTs.

Methods: We used a database of neurosurgical RCTs (trials published from 1961 to 2016) to identify studies of functional neurosurgical procedures (N = 48). We extracted data on the design and quality of these RCTs and quantified the quality of trials using Jadad scores. We categorized RCTs based on the device approval status at the time of the trial and tested the association of device approval status with trial design and quality parameters.

Results: Of the 48 analyzed functional neurosurgery RCTs, the median trial size was 34.5 patients with a median age of 51. The most common indications were Parkinson's disease (N = 20), epilepsy (N = 10), obsessive-compulsive disorder (N = 4), and pain (N = 4). Most trials reported inclusion and exclusion criteria (95.8%), sample size per arm (97.9%), and baseline characteristics of the patients being studied (97.9%). However, reporting of allocation concealment (29.2%), randomization mode (66.7%), and power calculations (54.2%) were markedly less common. We observed that trial quality has improved over time (Spearman r, 0.49). We observed that trials studying devices with humanitarian device exemption (HDE) and experimental indications (EI) tended to be of higher quality than trials of FDA-approved devices (p = 0.011). A key distinguishing quality characteristic was the proportion of HDE and EI trials that were double-blinded, compared to trials of FDA-approved devices (HDE, 83.3%; EI, 69.2%; FDA-approved, 35.3%). Although more than one-third of functional neurosurgery RCTs reported funding from industry, no significant association was identified between funding source and trial quality or outcome.

Conclusion: The quality of RCTs in functional neurosurgery has improved over time but reporting of specific metrics such as power calculations and allocation concealment requires further improvement. Device approval status but not funding source was associated with trial quality.
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http://dx.doi.org/10.1111/ner.13083DOI Listing
June 2020

Robotic-Assisted Spine Surgery: History, Efficacy, Cost, And Future Trends.

Robot Surg 2019 7;6:9-23. Epub 2019 Nov 7.

Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.

Robot-assisted spine surgery has recently emerged as a viable tool to enable less invasive and higher precision surgery. The first-ever spine robot, the SpineAssist (Mazor Robotics Ltd., Caesarea, Israel), gained FDA approval in 2004. With its ability to provide real-time intraoperative navigation and rigid stereotaxy, robotic-assisted surgery has the potential to increase accuracy while decreasing radiation exposure, complication rates, operative time, and recovery time. Currently, robotic assistance is mainly restricted to spinal fusion and instrumentation procedures, but recent studies have demonstrated its use in increasingly complex procedures such as spinal tumor resections and ablations, vertebroplasties, and deformity correction. However, robots do require high initial costs and training, and thus, require justification for their incorporation into common practice. In this review, we discuss the history of spinal robots along as well as currently available systems. We then examine the literature to evaluate accuracy, operative time, complications, radiation exposure, and costs - comparing robotic-assisted to traditional fluoroscopy-assisted freehand approaches. Finally, we consider future applications for robots in spine surgery.
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http://dx.doi.org/10.2147/RSRR.S190720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6844237PMC
November 2019