The impact of surgeon experience on perioperative complications and operative measures following thoracolumbar 3-column osteotomy for adult spinal deformity: overcoming the learning curve

The Case for Operative Efficiency in Adult Spinal Deformity Surgery: Impact of Operative Time on Complications, Length of Stay, Alignment, Fusion Rates, and Patient-Reported Outcomes

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To analyze the impact of operative room (OR) time in adult spinal deformity (ASD) surgery on patient outcomes.

BACKGROUND

It is currently unknown if OR time in ASD patients matched for deformity severity and surgical invasiveness is associated with patient outcomes.

MATERIALS AND METHODS

ASD patients with baseline and two-year postoperative radiographic and patient-reported outcome measures (PROM) data, undergoing a posterior-only approach for long fusion (>L1-Ilium) were included. Patients were grouped into short OR time (<40th percentile: <359 min) and long OR time (>60th percentile: >421 min). Groups were matched by age, baseline deformity severity, and surgical invasiveness. Demographics, radiographic, PROM data, fusion rate, and complications were compared between groups at baseline and two years follow-up.

RESULTS

In total, 270 patients were included for analysis: the mean OR time was 286 minutes in the short OR group versus 510 minutes in the long OR group ( P <0.001). Age, gender, percent of revision cases, surgical invasiveness, pelvic incidence minus lumbar lordosis, sagittal vertical axis, and pelvic tilt were comparable between groups ( P >0.05). Short OR had a slightly lower body mass index than the short OR group ( P <0.001) and decompression was more prevalent in the long OR time ( P =0.042). Patients in the long group had greater hospital length of stay ( P =0.02); blood loss ( P <0.001); proportion requiring intensive care unit ( P =0.003); higher minor complication rate ( P =0.001); with no significant differences for major complications or revision procedures ( P >0.5). Both groups had comparable radiographic fusion rates ( P =0.152) and achieved improvement in sagittal alignment measures, Oswestry disability index, and Short Form-36 ( P <0.001).

CONCLUSION

Shorter OR time for ASD correction is associated with a lower minor complication rate, a lower estimated blood loss, fewer intensive care unit admissions, and a shorter hospital length of stay without sacrificing alignment correction or PROMs. Maximizing operative efficiency by minimizing OR time in ASD surgery has the potential to benefit patients, surgeons, and hospital systems.

Surgeon Experience Is the Most Important Predictor of Case Failure Rate for Anterior Odontoid Screw Fixation: A Large Database Study

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

Determine risk factors and failure rate of anterior odontoid screw fixation surgery.

SUMMARY OF BACKGROUND DATA

Anterior odontoid screw fixation (AOSF) stabilizes type II dens fractures while preserving cervical motion. Despite having potential advantages, AOSF's failure rate and factors contributing to failure remain unknown.

MATERIALS AND METHODS

We identified AOSF patients in the national claims database Pearldiver using CPT code 22318. Failure was defined as the requirement of supplementary posterior fusion surgery in the C1-C2 or occiput-C2 region after the AOSF. We considered potential predictors of failure including age, sex, Charlson Comorbidity Index (CCI), surgeon experience, history of osteoporosis, obesity, and tobacco use. Univariate comparison analysis and logistic regression were conducted to identify factors associated with the need for additional posterior surgery.

RESULTS

For 2008 identified cases of AOSF, 249 cases (12.4%) required additional posterior fusion. Seventy-one of the 249 cases (28.5%) underwent revision surgery on the same day as the AOSF. Over 86% of revisions (215 cases) occurred within 200 days of the initial procedure. Posterior fusion rates are inversely correlated with surgeon experience, with the most experienced surgeons having a rate of 10.0%, followed by 11.5% for moderately experienced surgeons, and 15.0% for the least experienced surgeons. When comparing moderate and inexperienced surgeons to experienced surgeons, the odds ratios for posterior fusion were 1.18 (P>0.05) and 1.61 (P<0.006), respectively. Logistic regression revealed that both lesser experience (odds ratio=1.50) and osteoporosis (odds ratio=1.44) were the only factors significantly associated with failure (P<0.05).

CONCLUSIONS

Our findings indicate a correlation between AOSF success and surgeon experience. While currently published results suggest higher success rates, most of this data originates from experienced surgeons and specialized centers, therefore, they may not accurately reflect the failure rate encountered in a more general practice setting.

LEVEL OF EVIDENCE

Level III.

Specialty Impact on Patient Outcomes: Paving a Way for an Integrated Approach to Spinal Disorders

Spinal surgical procedures are steadily increasing globally due to broad indications of certain techniques encompassing a wide spectrum of conditions, including degenerative spine disorders, congenital anomalies, spinal metastases, and traumatic spinal fractures. The two specialties, neurosurgery (NS) and orthopedic surgery (OS), both possess the clinical adeptness to perform these procedures. With the advancing focus on comparative effectiveness research, it is vital to compare patient outcomes in spine surgeries performed by orthopedic surgeons and neurosurgeons, given their distinct approaches and training backgrounds to guide hospital programs and physicians to consider surgeon specialty when making informed decisions. Our review of the available literature revealed no significant difference in postoperative outcomes in terms of blood loss, neurological deficit, dural injury, intraoperative complications, and postoperative wound dehiscence in procedures performed by neurosurgeons and orthopedic surgeons. An increase in blood transfusion rates among patients operated by orthopedic surgeons and a longer operative time of procedures performed by neurosurgeons was a consistent finding among several studies. Other findings include a prolonged hospital stay, higher hospital readmission rates, and lower cost of procedures in patients operated on by orthopedic surgeons. A few studies revealed lower sepsis rates unplanned intubation rates and higher incidence of urinary tract infections (UTIs) and pneumonia postoperatively among patient cohorts operated by neurosurgeons. Certain limitations were identified in the studies including the use of large databases with incomplete information related to patient and surgeon demographics. Hence, it is imperative to account for these confounding variables in future studies to alleviate any biases. Nevertheless, it is essential to embrace a multidisciplinary approach integrating the surgical expertise of the two specialties and develop standardized management guidelines and techniques for spinal disorders to mitigate complications and enhance patient outcomes.

Development and validation of a novel thoracic spinal stenosis surgical invasiveness index: a single-center study based on 989 patients

BACKGROUND CONTEXT

Surgical invasiveness indices have been established for general spine surgery (surgical invasiveness index [SII]), spine deformity, and metastatic spine tumors; however, a specific index for thoracic spinal stenosis (TSS) has not been developed.

PURPOSE

To develop and validate a novel invasiveness index, incorporating TSS-specific factors for open posterior TSS surgery, which may facilitate the prediction of operative duration and intraoperative blood loss, and the stratification of surgical risk.

STUDY DESIGN

A retrospective observational study.

PATIENT SAMPLE

Overall, 989 patients who underwent open posterior TSS surgeries at our institution during the past 5 years were included.

OUTCOME MEASURES

The operation duration, estimated blood loss, transfusion status, major surgical complications, length of hospital stay, and medical expenses.

METHODS

We retrospectively analyzed the data of 989 consecutive patients who underwent posterior surgery for TSS between March 2017 and February 2022. Among them, 70% (n=692) were randomly placed in a training cohort, and the remaining 30% (n=297) automatically constituted the validation cohort. Multivariate linear regression models of operative time and log-transformed estimated blood loss were created using TSS-specific factors. Beta coefficients derived from these models were used to construct a TSS invasiveness index (TII). The ability of the TII to predict surgical invasiveness was compared with that of the SII and assessed in a validation cohort.

RESULTS

The TII was more strongly correlated with operative time and estimated blood loss (p<.05) and explained more variability in operative time and estimated blood loss than the SII (p<.05). The TII explained 64.2% of operative time and 34.6% of estimated blood loss variation, whereas the SII explained 38.7% and 22.5%, respectively. In further verification, the TII was more strongly associated with transfusion rate, drainage time, and length of hospital stay than SII (p<.05).

CONCLUSIONS

By incorporating TSS-specific components, the newly developed TII more accurately predicts the invasiveness of open posterior TSS surgery than the previous index.

Surgical Experience Affects the Outcome of Central Venous Access Catheter Implantation in Children: A Retrospective Cohort Study

INTRODUCTION

Surgical complications occur in up to third of children, limiting the benefits of tunneled central venous catheters (tCVCs) in children. We aimed to identify risk factors for complications related to catheter implantation.

METHODS

All children and adolescents undergoing tCVC implantation at a single center over a period of 9 years were analyzed. Infection, thrombosis, dislocation, and catheter dysfunction were defined as complications. Both patient-related (ie, age, sex, vessel characteristics, revision surgery) and surgical factors (ie, sex of surgeon, surgical experience) were analyzed for their association with complications.

RESULTS

A total of 1024 catheters were inserted, 887 ports and 137 broviac catheters. In terms of patient-related factors, Broviac catheters, and nononcological patients had a higher complication rate. The use of the internal jugular vein and revision surgery was associated with significantly increased complications in patients with port catheters. Experience of the surgeon correlated with various outcome parameters. Implantation performed by an attending were associated with lower complication rates in comparison to those performed by residents. Within the resident group, insertions performed by experienced residents had more complications compared with those performed by residents during their first years.

CONCLUSION

The study suggests that the outcome of tCVCs insertion is affected by the type of catheter used, the utilized vessel and above all by surgical experience. Residents had significantly increased complication rates in comparison to board-certified surgeons and amongst resident's outcome got worse with increasing experience of the residents. The presence of an experienced attending did not compensate for this effect. To improve the outcome of tCVCs, strategies like direct feedback after every procedure to achieve proficiency should be implanted in residency programs.

Increased Surgeon-specific Experience and Volume is Correlated With Improved Clinical Outcomes in Lumbar Fusion Patients

STUDY DESIGN

The present study design was that of a single center, retrospective cohort study to evaluate the influence of surgeon-specific factors on patient functional outcomes at 6 months following lumbar fusion. Retrospective review of a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis identified the present study population.

OBJECTIVE

This study seeks to evaluate surgeon-specific variable effects on patient-reported outcomes such as Oswestry Disability Index (ODI) and the effect of North American Spine Society (NASS) concordance on outcomes in the setting of variable surgeon characteristics.

SUMMARY OF BACKGROUND DATA

Lumbar fusion is one of the fastest growing procedures performed in the United States. Although the impact of surgeon-specific factors on patient-reported outcomes has been contested, studies examining these effects are limited.

METHODS

This is a single center, retrospective cohort study analyzing a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis by 1 of 5 neurosurgery fellowship trained spine surgeons. The primary outcome was improvement of ODI at 6 months postoperative follow-up compared with preoperative ODI.

RESULTS

A total of 307 patients were identified for analysis. Overall, 62% of the study population achieved minimum clinically important difference (MCID) in ODI score at 6 months. Years in practice and volume of lumbar fusions were statistically significant independent predictors of MCID ODI on multivariable logistic regression ( P =0.0340 and P =0.0343, respectively). Concordance with evidence-based criteria conferred a 3.16 (95% CI: 1.03, 9.65) times greater odds of achieving MCID.

CONCLUSION

This study demonstrates that traditional surgeon-specific variables predicting surgical morbidity such as experience and procedural volume are also predictors of achieving MCID 6 months postoperatively from lumbar fusion. Independent of surgeon factors, however, adhering to evidence-based guidelines can lead to improved outcomes.

Machine Learning Models for Predicting Postoperative Outcomes following Skull Base Meningioma Surgery

Objective  While predictive analytic techniques have been used to analyze meningioma postoperative outcomes, to our knowledge, there have been no studies that have investigated the utility of machine learning (ML) models in prognosticating outcomes among skull base meningioma patients. The present study aimed to develop models for predicting postoperative outcomes among skull base meningioma patients, specifically prolonged hospital length of stay (LOS), nonroutine discharge disposition, and high hospital charges. We also validated the predictive performance of our models on out-of-sample testing data. Methods  Patients who underwent skull base meningioma surgery between 2016 and 2019 at an academic institution were included in our study. Prolonged hospital LOS and high hospital charges were defined as >4 days and >$47,887, respectively. Elastic net logistic regression algorithms were trained to predict postoperative outcomes using 70% of available data, and their predictive performance was evaluated on the remaining 30%. Results  A total of 265 patients were included in our final analysis. Our cohort was majority female (77.7%) and Caucasian (63.4%). Elastic net logistic regression algorithms predicting prolonged LOS, nonroutine discharge, and high hospital charges achieved areas under the receiver operating characteristic curve of 0.798, 0.752, and 0.592, respectively. Further, all models were adequately calibrated as determined by the Spiegelhalter Z -test ( p >0.05). Conclusion  Our study developed models predicting prolonged hospital LOS, nonroutine discharge disposition, and high hospital charges among skull base meningioma patients. Our models highlight the utility of ML as a tool to aid skull base surgeons in providing high-value health care and optimizing clinical workflows.

Predictors of surgical site infection in glioblastoma patients undergoing craniotomy for tumor resection

OBJECTIVE

Surgical site infections (SSIs) burden patients and healthcare systems, often requiring additional intervention. The objective of this study was to identify the relationship between preoperative predictors inclusive of scalp incision type and postoperative SSI following glioblastoma resection.

METHODS

The authors retrospectively reviewed cases of glioblastoma resection performed at their institution from December 2006 to December 2019 and noted preoperative demographic and clinical presentations, excluding patients missing these data. Preoperative nutritional indices were available for a subset of cases. Scalp incisions were categorized as linear/curvilinear, reverse question mark, trapdoor, or frontotemporal. Patients were dichotomized by SSI incidence. Multivariable logistic regression was used to determine predictors of SSI.

RESULTS

A total of 911 cases of glioblastoma resection were identified, 30 (3.3%) of which demonstrated postoperative SSI. There were no significant differences in preoperative malnutrition or number of surgeries between SSI and non-SSI cases. The SSI cases had a significantly lower preoperative Karnofsky Performance Status (KPS) than the non-SSI cases (63.0 vs 75.1, p < 0.0001), were more likely to have prior radiation history (43.3% vs 26.4%, p = 0.042), and were more likely to have received steroids both preoperatively and postoperatively (83.3% vs 54.5%, p = 0.002). Linear/curvilinear incisions were more common in non-SSI than in SSI cases (56.9% vs 30.0%, p = 0.004). Trapdoor scalp incisions were more frequent in SSI than non-SSI cases (43.3% vs 24.2%, p = 0.012). On multivariable analysis, a lower preoperative KPS (OR 1.04, 95% CI 1.02–1.06), a trapdoor scalp incision (OR 3.34, 95% CI 1.37–8.49), and combined preoperative and postoperative steroid administration (OR 3.52, 95% CI 1.41–10.7) were independently associated with an elevated risk of postoperative SSI.

CONCLUSIONS

The study findings indicated that SSI risk following craniotomy for glioblastoma resection may be elevated in patients with a low preoperative KPS, a trapdoor scalp incision during surgery, and steroid treatment both preoperatively and postoperatively. These data may help guide future operative decision-making for these patients.

Novel Predictive Models for High-Value Care Outcomes Following Glioblastoma Resection

BACKGROUND

Treating patients with glioblastoma (GBM) requires extensive medical infrastructure. Individualized risk assessment for extended length of stay (LOS), nonroutine discharge disposition, and increased total hospital charges is critical to optimize delivery of care. Our study sought to develop predictive models identifying independent risk factors for these outcomes.

METHODS

We retrospectively reviewed patients undergoing GBM resection at our institution between January 2017 and September 2020. Extended LOS and elevated hospital charges were defined as values in the upper quartile of the cohort. Nonroutine discharge was defined as any disposition other than to home. Multivariate models for each outcome included covariates demonstrating P ≤ 0.10 on bivariate analysis.

RESULTS

We identified 265 patients undergoing GBM resection, with an average age of 58.2 years. 24.5% of patients experienced extended LOS, 22.6% underwent nonroutine discharge, and 24.9% incurred elevated total hospital charges. Decreasing Karnofsky Performance Status (KPS) (P = 0.004), increasing modified 5-factor frailty (mFI-5) index (P = 0.012), lower surgeon experience (P = 0.005), emergent surgery (P < 0.0001), and larger tumor volume (P < 0.0001) predicted extended LOS. Independent predictors of nonroutine discharge included older age (P = 0.02), decreasing KPS (P < 0.0001), and emergent surgery (P = 0.048). Nonprivate insurance (P = 0.011), decreasing KPS (P = 0.029), emergent surgery (P < 0.0001), and larger tumor volume (P = 0.004) predicted elevated hospital charges. These models were incorporated into an open-access online calculator (https://neurooncsurgery3.shinyapps.io/gbm_calculator/).

CONCLUSIONS

Several factors were independent predictors for at least 1 high-value care outcome, with lower KPS and emergent admission associated with each outcome. These models and our calculator may help clinicians provide individualized postoperative risk assessment to glioblastoma patients.

Management and surgical outcomes of dystrophic scoliosis in neurofibromatosis type 1: a systematic review

OBJECTIVE

Neurofibromatosis type 1 (NF1) dystrophic scoliosis is an early-onset, rapidly progressive multiplanar deformity. There are few studies on the surgical management of this patient population. Specifically, perioperative morbidity, instrument-related complications, and quality-of-life outcomes associated with surgical management have not been systematically evaluated. In this study, the authors aimed to perform a systematic review on the natural history, management options, and surgical outcomes in patients who underwent NF1 dystrophic scoliosis surgery.

METHODS

A PubMed search for articles with “neurofibromatosis” and either “dystrophic” or “scoliosis” in the title or abstract was performed. Articles with 10 or more patients undergoing surgery for NF1 dystrophic scoliosis were included. Data regarding indications, treatment details, morbidity, and outcomes were summarized and analyzed with descriptive statistics.

RESULTS

A total of 310 articles were identified, 48 of which were selected for full-text review; 30 studies describing 761 patients met the inclusion criteria. The mean age ranged from 7 to 22 years, and 99.7% of patients were younger than 18 years. The mean preoperative coronal Cobb angle was 75.2°, and the average correction achieved was 40.3°. The mean clinical follow-up in each study was at least 2 years (range 2.2–19 years). All patients underwent surgery with the intent of deformity correction. The scoliosis regions addressed were thoracic curves (69.6%) and thoracolumbar (11.1%) and lumbar (14.3%) regions. The authors reported on a variety of approaches: posterior-only, combined anterior-posterior, and growth-friendly surgery. For fixation techniques, 42.5% of patients were treated with hybrid constructs, 51.5% with pedicle screw–only constructs, and 6.0% with hook-based constructs. Only 0.9% of patients underwent a vertebral column resection. The nonneurological complication rate was 14.0%, primarily dural tears and wound infections. The immediate postoperative neurological deficit rate was 2.1%, and the permanent neurological deficit rate was 1.2%. Ultimately, 21.5% required revision surgery, most commonly for implant-related complications. Loss of correction in both the sagittal and coronal planes commonly occurred at follow-up. Five papers supplied validated patient-reported outcome measures, showing improvement in the mental health, self-image, and activity domains.

CONCLUSIONS

Data on the surgical outcomes of dystrophic scoliosis correction are heterogeneous and sparse. The perioperative complication rate appears to be high, although reported rates of neurological deficits appear to be lower than clinically observed and may be underreported. The incidence of implant-related failures requiring revision surgery is high. There is a great need for multicenter prospective studies of this complex type of deformity.

The Effect of Systemic Tranexamic Acid on Hypercoagulable Complications and Perioperative Outcomes Following Three-Column Osteotomy for Adult Spinal Deformity

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Thoracolumbar 3-column osteotomy (3CO) is a powerful technique for correction of rigid adult spinal deformity (ASD). However, it can be associated with high-volume blood loss. This study seeks to investigate the efficacy and safety of tranexamic acid (TXA) in 3CO ASD patients.

METHODS

ASD patients who underwent 3CO from 2006 to 2019 were retrospectively reviewed. Outcomes were compared between TXA and non-TXA patients, and TXA doses.

RESULTS

A total of 365 ASD patients were included: 181 TXA and 184 non-TXA. The mean age was 64.6 years and 60.5% were female. Operative time was shorter in the TXA group (295.6 vs 320.2 minutes, P < .001). However, TXA was not associated with shorter operative time (β = -6.5 minutes, 95% CI -29.0 to 15.9, P = .567) after accounting for surgeon experience. There was no difference in blood loss (2020.2 vs 1914.1 mL, P = .437) between groups. Overall complications (37.0% vs 33.2%, P = .439), including hypercoagulable (2.2% vs 3.8%, P = .373) and cardiac (13.3% vs 7.1%, P = .050) complications were similar between groups. TXA was not independently associated with blood loss or TXA-related complications. Both groups had comparable intensive care unit (2.5 vs 2.0 days, P = .060) and hospital (8.9 vs 8.2 days, P = .190) stays. There were no differences in outcomes between TXA dosing subgroups.

CONCLUSIONS

Systemic TXA use during 3CO for ASD surgery was not associated with decreased blood loss. TXA patients had shorter operative times, but this was driven mainly by surgeon experience on multivariate analysis. Routine use of TXA is safe and does not increase the incidence of hypercoagulable complications even at high doses.

Impact of Surgeon Experience on Outcomes of Anterior Cervical Discectomy and Fusion

INTRODUCTION

The relationship between surgeon experience and cervical fusion outcomes has yet to be assessed. We investigate perioperative characteristics, patient-reported outcomes (PROMs), and minimal clinically important difference (MCID) achievement after anterior cervical diskectomy and fusion (ACDF) by the volume of cases done throughout an orthopaedic spine surgeon's career.

METHODS

ACDF procedures between 2005 and 2020 were identified. Group I included the first half of ACDF cases (#1-#321). PROMs were introduced in the second half of the ACDF cases; thus, the next 322 cases were subdivided to compare PROM and MCID between subgroups (cases #322 to #483 = group II and #484 to #645 = group III). PROMs, including VAS back/leg, Oswestry Disability Index (ODI), Short Form-12 Physical Composite Score, and PROMIS-PF, were collected preoperatively/postoperatively. Demographics, perioperative variables, mean PROMs, and MCID achievement were compared between groups and subgroups using the Student t-test and chi-square. Logistic regression evaluated MCID achievement using the established threshold values.

RESULTS

A total of 642 patients were included (320 in group I, 161 in group II, and 161 in group III). The latter cases had significantly decreased surgical time, blood loss, and postoperative length of stay in comparison of groups and subgroups (P ≤ 0.002, all). CT-confirmed 1-year arthrodesis rates were increased among the latter cases (P = 0.045). Group II had significantly higher arthrodesis rates than group III (P = 0.039). The postoperative complication rates were lower in the latter cases (P < 0.001, all), whereas subgroup analysis revealed lower incidence of urinary retention and other complications in group III (P ≤ 0.031, all). Mean PROMs were significantly inferior in group II versus group III for VAS neck at 6 months (P = 0.030), Neck Disability Index at 6 months preoperatively (P ≤ 0.022, both), Short Form-12 Physical Composite Score at 12 weeks/2 years (P ≤ 0.047, both), and PROMIS-PF at 12 weeks/6 months (P ≤ 0.036, both). The MCID attainment rates were higher among group III for VAS neck/Neck Disability Index at 2 years (P ≤ 0.005) and overall achievement across all PROMs (P ≤ 0.015, all).

DISCUSSION

Increased ACDF case volume may lead to markedly decreased surgical time, blood loss, and length of postoperative stay as well as improved clinical outcomes in pain, disability, and physical function.

Quality metrics in adult spinal deformity surgery over the last decade: a combined analysis of the largest prospective multicenter data sets

OBJECTIVE

The reported rate of complications and cost of adult spinal deformity (ASD) surgery, associated with an exponential increase in the number of surgeries, cause alarm among healthcare payers and providers worldwide. The authors conjointly analyzed the largest prospective available ASD data sets to define trends in quality-of-care indicators (complications, reinterventions, and health-related quality of life [HRQOL] outcomes) since 2010.

METHODS

This is an observational prospective longitudinal cohort study. Patients underwent surgery between January 2010 and December 2016, with > 2 years of follow-up data. Demographic, surgical, radiological, and HRQOL (i.e., Oswestry Disability Index, SF-36, Scoliosis Research Society-22r) data obtained preoperatively and at 3, 6, 12, and 24 months after surgery were evaluated. Trends and changes in indicators were analyzed using local regression (i.e., locally estimated scatterplot smoothing [LOESS]) and adjusted odds ratio (OR).

RESULTS

Of the 2286 patients included in the 2 registries, 1520 underwent surgery between 2010 and 2016. A total of 1151 (75.7%) patients who were treated surgically at 23 centers in 5 countries met inclusion criteria. Patient recruitment increased progressively (2010-2011 vs 2015-2016: OR 1.64, p < 0.01), whereas baseline clinical characteristics (age, American Society of Anesthesiologists class, HRQOL scores, sagittal deformity) did not change. Since 2010 there has been a sustained reduction in major and minor postoperative complications observed at 90 days (major: OR 0.59; minor: OR 0.65; p < 0.01); at 1 year (major: OR 0.52; minor: 0.75; p < 0.01); and at 2 years of follow-up (major: OR 0.4; minor: 0.80; p < 0.01) as well as in the 2-year reintervention rate (OR 0.41, p < 0.01). Simultaneously, there has been a slight improvement in the correction of sagittal deformity (i.e., pelvic incidence-lumbar lordosis mismatch: OR 1.11, p = 0.19) and a greater gain in quality of life (i.e., Oswestry Disability Index 26% vs 40%, p = 0.02; Scoliosis Research Society-22r, self-image domain OR 1.16, p = 0.13), and these are associated with a progressive reduction of surgical aggressiveness (number of fused segments: OR 0.81, p < 0.01; percent pelvic fixation: OR 0.66, p < 0.01; percent 3-column osteotomies: OR 0.63, p < 0.01).

CONCLUSIONS

The best available data show a robust global improvement in quality metrics in ASD surgery over the last decade. Surgical complications and reoperations have been reduced by half, while improvement in disability increased and correction rates were maintained, in patients with similar baseline characteristics.

Predicting High-Value Care Outcomes After Surgery for Non-Skull Base Meningiomas

OBJECTIVE

A need exists to better understand the prognostic factors that influence high-value care outcomes after meningioma surgery. The goal of the present study was to develop predictive models to determine the patients at risk of experiencing an extended hospital length of stay (LOS), nonroutine discharge disposition, and/or a 90-day hospital readmission after non-skull base meningioma resection.

METHODS

In the present study, we analyzed the data from 396 patients who had undergone surgical resection of non-skull base meningiomas at a single institution between January 1, 2005 and December 31, 2020. The Mann-Whitney U test was used for bivariate analysis of the continuous variables and the Fisher exact test for bivariate analysis of the categorical variables. A multivariate analysis was conducted using logistic regression models.

RESULTS

Most patients had had a falcine or parasagittal meningioma (66.2%), with the remainder having convexity (31.8%) or intraventricular (2.0%) tumors. Nonelective surgery (P < 0.0001) and an increased tumor volume (P = 0.0022) were significantly associated with a LOS >4 days on multivariate analysis. The independent predictors of a nonroutine discharge disposition included male sex (P = 0.0090), nonmarried status (P = 0.024), nonelective surgery (P = 0.0067), tumor location within the parasagittal or intraventricular region (P = 0.0084), and an increased modified frailty index score (P = 0.039). Hospital readmission within 90 days was independently associated with nonprivate insurance (P = 0.010) and nonmarried status (P = 0.0081). Three models predicting for a prolonged LOS, nonroutine discharge disposition, and 90-day readmission were implemented in the form of an open-access, online calculator (available at: https://neurooncsurgery3.shinyapps.io/non_skull_base_meningiomas/).

CONCLUSIONS

After external validation, our open-access, online calculator could be useful for assessing the likelihood of adverse postoperative outcomes for patients undergoing surgery of non-skull base meningioma.

Artificial intelligence for adult spinal deformity: current state and future directions

As we experience a technological revolution unlike any other time in history, spinal surgery as a discipline is poised to undergo a dramatic transformation. As enormous amounts of data become digitized and more readily available, medical professionals approach a critical juncture with respect to how advanced computational techniques may be incorporated into clinical practices. Within neurosurgery, spinal disorders in particular, represent a complex and heterogeneous disease entity that can vary dramatically in its clinical presentation and how it may impact patients' lives. The spectrum of pathologies is extremely diverse, including many different etiologies such as trauma, oncology, spinal deformity, infection, inflammatory conditions, and degenerative disease among others. The decision to perform spine surgery, especially complex spine surgery, involves several nuances due to the interplay of biomechanical forces, bony composition, neurologic deficits, and the patient's desired goals. Adult spinal deformity as an example is one of the most complex, given its involvement of not only the spine, but rather the entirety of the skeleton in order to appreciate radiographic completeness. With the vast array of variables contributing to spinal disorders, treatment algorithms can vary significantly, and it is very difficult for surgeons to predict how patients will respond to surgery. As such, it will become imperative for spine surgeons to utilize the burgeoning availability of advanced computational tools to process unprecedented amounts of data and provide novel insights into spinal disease. These tools range from predictive models built using machine learning algorithms, to deep learning methods for imaging analysis, to natural language processing that can mine text from electronic medical records or transcribed patient visits - all to better treat the intricacies of spinal disorders. The adoption of such techniques will empower patients and propel spine surgeons into the era of personalized medicine, by allowing clinical plans to be tailored to address individual patients' needs. This paper, which exists in the context of a larger body of literatutre, provides a comprehensive review of the current state and future of artificial intelligence and machine learning with a particular emphasis on Adult spinal deformity surgery.

Patient-Specific Factors Drive Intensive Care Unit and Total Hospital Length of Stay in Operative Patients with Brain Tumor

BACKGROUND

Hospital length of stay (LOS) is an important cost driver in neurosurgery. Broader surgical literature has shown that patient-related factors, including comorbidities, and procedure-related factors, such surgeon experience, may be associated with LOS. Because value optimization strategies may be targeted toward either domain, this study investigated the contributions of patient-related and procedure-related factors in predicting prolonged intensive care unit LOS (iLOS) and total hospital LOS (tLOS).

METHODS

Data for adult patients undergoing brain tumor surgery (2017-2019) were collected. Bivariate analyses for iLOS and tLOS were performed using the Mann-Whitney U test and Fisher exact test. Variables associated with either outcome with P < 0.10 were included in patient-only, procedure-only, and patient+procedure factor multivariate linear regression models. Model discrimination was quantified using C-statistics.

RESULTS

Our 654 patients had a mean age of 57.54 years (standard deviation, ± 14.34 years). For iLOS, the patient-only model significantly outperformed the procedure-only model (P < 0.0001) and performed similarly to the patient+procedure model (P = 0.50). Other than tumor diagnosis, 5-Factor Modified Frailty Index score was the only factor associated with iLOS (P < 0.001) and tLOS (P < 0.001) on multivariate analysis. When predicting prolonged tLOS, the patient-only model significantly outperformed the procedure-only model (P < 0.0001), and performed similarly to patient+procedure models (P = 0.49).

CONCLUSIONS

Patient-specific factors are the main drivers of prolonged iLOS and tLOS among patients with brain tumor. Frailty was significantly associated with both iLOS and tLOS on multivariate analysis. Efforts to improve care value should focus on strategies to optimize patient status, such as prehabilitation and enhanced recovery after surgery.

Multilevel Pedicle Subtraction Osteotomy for Correction of Severe Rigid Adult Spinal Deformities: A Case Series, Indications, Considerations, and Literature Review

BACKGROUND

Rigid and ankylosed thoracolumbar spinal deformities require three-column osteotomy (3CO) to achieve adequate correction. For severe and multiregional deformities, multilevel 3CO is required but its use and outcomes are rarely reported.

OBJECTIVE

To describe the use of multilevel pedicle subtraction osteotomy (PSO) in adult spinal deformity (ASD) patients with severe, rigid, and ankylosed multiregional deformity.

METHODS

Retrospective review of 5 ASD patients who underwent multilevel PSO for the correction of severe fixed deformity and review the literature regarding the use of multilevel PSO.

RESULTS

Five patients presented with spinal imbalance secondary to regional and multiregional spinal deformities involving the thoracolumbar spine. All patients underwent a single-stage two-level noncontiguous PSO, and 2 of the patients underwent a staged third PSO to treat deformity involving a separate spinal region. Significant radiographic correction was achieved with normalization of spinal alignment and parameters. Two-level PSO was able to provide greater than 80 degrees of sagittal plane correction in both the lumbar and thoracic spine. Two patients experienced new postoperative weakness which recovered to preoperative baseline at 3 to 6 mo follow-up. At most recent follow-up, 4 of the 5 patients gained significant pain relief and had improved functionality.

CONCLUSION

Noncontiguous multilevel PSO is a formidable surgical technique. Additional risk (compared to single-level 3CO) comes in the form of greater blood loss and higher risk for postoperative weakness. Nonetheless, multilevel PSO is feasible and effective for correcting severe multiplanar and multiregional ASD, and patients gain significant benefits in increased functionality and pain relief.

Lead migration and fracture rate in dorsal root ganglion stimulation using anchoring and non-anchoring techniques: A multicenter pooled data analysis

INTRODUCTION

Dorsal root ganglion stimulation (DRG-S) is a neuromodulation technique introduced in the last decade with evolving implant methods. Initial prospective research found low incidences of lead migration and lead fracture with DRG-S. However, several recent studies have highlighted high lead migration and lead fracture rates with DRG-S. We investigated the influence of lead anchoring on migrations and fractures.

METHODS

We performed a retrospective review between 2016 and 2020 of individuals implanted with DRG-S leads by 4 experienced implanters. The implanters independently changed their standard practice regarding lead anchoring over time, with opposing trends (no anchoring > anchoring, anchoring > no anchoring). We compared lead migration and lead fracture rates between anchored and unanchored DRG-S leads in the entire study cohort. Cox regression was performed on lead migration and fracture distributions.

RESULTS

We included 756 leads (n = 565 anchored and n = 191 unanchored) from 249 patients. In unanchored leads, migration occurred in 16 leads (8.4%) from 13 patients (21.0%). In anchored leads, migration occurred in 8 leads (1.4%) from 5 patients (2.7%). Fracture in unanchored leads occurred in 6 leads (3.1%) from 6 patients (9.7%). Fractures in anchored leads occurred in 11 leads (1.9%) from 9 patients (4.8%). The migration survival distributions for the anchored and unanchored leads were statistically significantly different (p < 0.01) with decreased survival for unanchored leads (hazard ratio = 5.8, 95% confidence interval [CI] = 2.2-15.5).

DISCUSSION

We found that anchoring DRG-S leads significantly reduces lead migration when compared to leads placed without an anchor. There was no significant difference in fracture rate between anchored and unanchored leads.

Trends in Diagnosis and Treatment of Sacroiliac Joint Pathology Over the Past 10 Years: Review of Scientific Evidence for New Devices for Sacroiliac Joint Fusion

Sacroiliac (SI) joint pathology is a newly appreciated contributor to lower back pain. Sacroiliac joint fusion (SIJF) has grown rapidly in popularity in association with the advent of minimally-invasive surgical techniques. This has led to an explosion of new medical devices used for SIJF. The objective of this article is to outline clinical trends, summarize the current data, and categorize novel devices for SIJF. Trends in SI joint pathology and fusion were obtained via the Healthcare Cost and Utilization Project’s (HCUP) National Inpatient Sample (NIS) database and Web of Science. To review literature on devices for SIJF, PubMed was searched using the Boolean phrase “sacroiliac joint AND (fusion OR arthrodesis)” since 2010. To establish a list of SIJF devices not represented in the literature, searches were performed on the FDA 510(k), premarket approval, and de novo databases, as well as Google and LinkedIn. Literature review yielded 11 FDA-approved devices for minimally invasive SIJF. Database query yielded an additional 22 devices for a total of 33 devices. Twenty-one devices used the lateral transiliac approach, six posterior allograft approach, three posterolateral approach, and three combined the lateral transiliac and posterolateral approaches. The evidence for the lateral transiliac approach is the most robust. Many novel devices have been developed for minimally invasive SIJF over the past 10 years. Further randomized comparative trials are warranted to evaluate different surgical approaches and novel devices at this time.

Reducing revision rates following Pedicle Subtraction Osteotomy surgery: a single-center experience of trends over 7 years in patients with Adult Spinal Deformity

STUDY DESIGN

This is a single-center, retrospective study.

OBJECTIVE

To assess if implemented changes to clinical practice have reduced mechanical complications following pedicle subtraction osteotomy (PSO) surgery. Adult spinal deformity (ASD) is increasing in prevalence with concurrent increasing demands for surgical treatment. The most extensive technique, PSO, allows for major correction of rigid deformities. However, surgery-related complications have been reported in rates up to 77% and especially mechanical complications occur at unsatisfactory frequencies.

METHODS

We retrospectively included all patients undergoing PSO for ASD between 2010 and 2016. Changes to clinical practice were introduced continuously in the study period, including rigorous patient selection; inter-disciplinary conferences; implant-material; number of surgeons; surgeon experience; and perioperative standardized protocols for pain, neuromonitoring and blood-loss management. Postoperative complications were recorded in the 2-year follow-up period. Competing risk survival analysis was used to assess cumulative incidence of revision surgery due to mechanical complications. The Mann-Kendall test was used for analysis of trends.

RESULTS

We included 185 patients undergoing PSO. The level of PSO changed over the study period (P < 0.01) with L3 being the most common level in 2010 compared to L4 in 2016. Both preoperative and surgical corrections of sagittal vertical axis were larger towards the end of the study period. The 2-year revision rate due to mechanical failure steadily declined over the study period from 52% in 2010 to 14% for patients treated in 2016, although without statistically significant trend (P = 0.072). In addition, rates of mechanical complications steadily declined over the study period and significant decreasing trends were observed in time trend analyses of overall complications, major complications and rod breakage.

CONCLUSIONS

We observed decreased risks of revision surgery due to mechanical complications following PSO in patients with ASD over a 7-year period. We attribute these improvements to advancements in patient selection, surgical planning and techniques, surgeon experience and more standardized perioperative care.

LEVEL OF EVIDENCE

III.

Predicting High-Value Care Outcomes After Surgery for Skull Base Meningiomas

BACKGROUND

Although various predictors of adverse postoperative outcomes among patients with meningioma have been established, research has yet to develop a method for consolidating these findings to allow for predictions of adverse health care outcomes for patients diagnosed with skull base meningiomas. The objective of the present study was to develop 3 predictive algorithms that can be used to estimate an individual patient's probability of extended length of stay (LOS) in hospital, experiencing a nonroutine discharge disposition, or incurring high hospital charges after surgical resection of a skull base meningioma.

METHODS

The present study used data from patients who underwent surgical resection for skull base meningiomas at a single academic institution between 2017 and 2019. Multivariate logistic regression analysis was used to predict extended LOS, nonroutine discharge, and high hospital charges, and 2000 bootstrapped samples were used to calculate an optimism-corrected C-statistic. The Hosmer-Lemeshow test was used to assess model calibration, and P < 0.05 was considered statistically significant.

RESULTS

A total of 245 patients were included in our analysis. Our cohort was mostly female (77.6%) and white (62.4%). Our models predicting extended LOS, nonroutine discharge, and high hospital charges had optimism-corrected C-statistics of 0.768, 0.784, and 0.783, respectively. All models showed adequate calibration (P>0.05), and were deployed via an open-access, online calculator: https://neurooncsurgery3.shinyapps.io/high_value_skull_base_calc/.

CONCLUSIONS

After external validation, our predictive models have the potential to aid clinicians in providing patients with individualized risk estimation for health care outcomes after meningioma surgery.

State-of-the-art reviews predictive modeling in adult spinal deformity: applications of advanced analytics

Adult spinal deformity (ASD) is a complex and heterogeneous disease that can severely impact patients' lives. While it is clear that surgical correction can achieve significant improvement of spinopelvic parameters and quality of life measures in adults with spinal deformity, there remains a high risk of complication associated with surgical approaches to adult deformity. Over the past decade, utilization of surgical correction for ASD has increased dramatically as deformity correction techniques have become more refined and widely adopted. Along with this increase in surgical utilization, there has been a massive undertaking by spine surgeons to develop more robust models to predict postoperative outcomes in an effort to mitigate the relatively high complication rates. A large part of this revolution within spine surgery has been the gradual adoption of predictive analytics harnessing artificial intelligence through the use of machine learning algorithms. The development of predictive models to accurately prognosticate patient outcomes following ASD surgery represents a dramatic improvement over prior statistical models which are better suited for finding associations between variables than for their predictive utility. Machine learning models, which offer the ability to make more accurate and reproducible predictions, provide surgeons with a wide array of practical applications from augmenting clinical decision making to more wide-spread public health implications. The inclusion of these advanced computational techniques in spine practices will be paramount for improving the care of patients, by empowering both patients and surgeons to more specifically tailor clinical decisions to address individual health profiles and needs.

Asymmetrical pedicle subtraction osteotomy for correction of concurrent sagittal-coronal imbalance in adult spinal deformity: a comparative analysis

OBJECTIVE

Rigid multiplanar thoracolumbar adult spinal deformity (ASD) cases are challenging and many require a 3-column osteotomy (3CO), specifically asymmetrical pedicle subtraction osteotomy (APSO). The outcomes and additional risks of performing APSO for the correction of concurrent sagittal-coronal deformity have yet to be adequately studied.

METHODS

The authors performed a retrospective review of all ASD patients who underwent 3CO during the period from 2006 to 2019. All cases involved either isolated sagittal deformity (patients underwent standard PSO) or concurrent sagittal-coronal deformity (coronal vertical axis [CVA] ≥ 4.0 cm; patients underwent APSO). Perioperative and 2-year follow-up outcomes were compared between patients with isolated sagittal imbalance who underwent PSO and those with concurrent sagittal-coronal imbalance who underwent APSO.

RESULTS

A total of 390 patients were included: 338 who underwent PSO and 52 who underwent APSO. The mean patient age was 64.6 years, and 65.1% of patients were female. APSO patients required significantly more fusions with upper instrumented vertebrae (UIV) in the upper thoracic spine (63.5% vs 43.3%, p = 0.007). Radiographically, APSO patients had greater deformity with more severe preoperative sagittal and coronal imbalance: sagittal vertical axis (SVA) 13.0 versus 10.7 cm (p = 0.042) and CVA 6.1 versus 1.2 cm (p < 0.001). In APSO cases, significant correction and normalization were achieved (SVA 13.0-3.1 cm, CVA 6.1-2.0 cm, lumbar lordosis [LL] 26.3°-49.4°, pelvic tilt [PT] 38.0°-20.4°, and scoliosis 25.0°-10.4°, p < 0.001). The overall perioperative complication rate was 34.9%. There were no significant differences between PSO and APSO patients in rates of complications (overall 33.7% vs 42.3%, p = 0.227; neurological 5.9% vs 3.9%, p = 0.547; medical 20.7% vs 25.0%, p = 0.482; and surgical 6.5% vs 11.5%, p = 0.191, respectively). However, the APSO group required significantly longer stays in the ICU (3.1 vs 2.3 days, p = 0.047) and hospital (10.8 vs 8.3 days, p = 0.002). At the 2-year follow-up, there were no significant differences in mechanical complications, including proximal junctional kyphosis (p = 0.352), pseudarthrosis (p = 0.980), rod fracture (p = 0.852), and reoperation (p = 0.600).

CONCLUSIONS

ASD patients with significant coronal imbalance often have severe concurrent sagittal deformity. APSO is a powerful and effective technique to achieve multiplanar correction without higher risk of morbidity and complications compared with PSO for sagittal imbalance. However, APSO is associated with slightly longer ICU and hospital stays.

Complication profile associated with S1 pedicle subtraction osteotomy compared with 3-column osteotomies at other thoracolumbar levels for adult spinal deformity: series of 405 patients with 9 S1 osteotomies

OBJECTIVE

There is an increased recognition of disproportional lumbar lordosis (LL) and artificially high pelvic incidence (PI) as a cause for positive sagittal imbalance and spinal pelvic mismatch. For such cases, a sacral pedicle subtraction osteotomy (PSO) may be indicated, although its morbidity is not well described. In this study, the authors evaluate the specific complication risks associated with S1 PSO.

METHODS

A retrospective review of all adult spinal deformity patients who underwent a 3-column osteotomy (3CO) for thoracolumbar deformity from 2006 to 2019 was performed. Demographic, clinical baseline, and radiographic parameters were recorded. The primary outcome of interest was perioperative complications (surgical, neurological, and medical). Secondary outcomes of interest included case length, blood loss, and length of stay. Multivariate analysis was used to assess the risk of S1 PSO compared with 3CO at other levels.

RESULTS

A total of 405 patients underwent 3CO in the following locations: thoracic (n = 55), L1 (n = 25), L2 (n = 29), L3 (n = 141), L4 (n = 129), L5 (n = 17), and S1 (n = 9). After S1 PSO, there were significant improvements in the sagittal vertical axis (14.8 cm vs 6.7 cm, p = 0.004) and PI-LL mismatch (31.7° vs 9.6°, p = 0.025) due to decreased PI (80.3° vs 65.9°, p = 0.006). LL remained unchanged (48.7° vs 57.8°, p = 0.360). The overall complication rate was 27.4%; the surgical, neurological, and medical complication rates were 7.7%, 6.2%, and 20.0%, respectively. S1 PSO was associated with significantly higher rates of overall complications: thoracic (29.1%), L1 (32.0%), L2 (31.0%), L3 (19.9%), L4 (32.6%), L5 (11.8%), and S1 (66.7%) (p = 0.018). Similarly, an S1 PSO was associated with significantly higher rates of surgical (thoracic [9.1%], L1 [4.0%], L2 [6.9%], L3 [5.7%], L4 [10.9%], L5 [5.9%], and S1 [44.4%], p = 0.006) and neurological (thoracic [9.1%], L1 [0.0%], L2 [6.9%], L3 [2.8%], L4 [7.0%], L5 [5.9%], and S1 [44.4%], p < 0.001) complications. On multivariate analysis, S1 PSO was independently associated with higher odds of overall (OR 7.93, p = 0.013), surgical (OR 20.66, p = 0.010), and neurological (OR 14.75, p = 0.007) complications.

CONCLUSIONS

S1 PSO is a powerful technique for correction of rigid sagittal imbalance due to an artificially elevated PI in patients with rigid high-grade spondylolisthesis and chronic sacral fractures. However, the technique and intraoperative corrective maneuvers are challenging and associated with high surgical and neurological complications. Additional investigations into the learning curve associated with S1 PSO and complication prevention are needed.

Artificial Intelligence for Adult Spinal Deformity

Adult spinal deformity (ASD) is a complex disease that significantly affects the lives of many patients. Surgical correction has proven to be effective in achieving improvement of spinopelvic parameters as well as improving quality of life (QoL) for these patients. However, given the relatively high complication risk associated with ASD correction, it is of paramount importance to develop robust prognostic tools for predicting risk profile and outcomes. Historically, statistical models such as linear and logistic regression models were used to identify preoperative factors associated with postoperative outcomes. While these tools were useful for looking at simple associations, they represent generalizations across large populations, with little applicability to individual patients. More recently, predictive analytics utilizing artificial intelligence (AI) through machine learning for comprehensive processing of large amounts of data have become available for surgeons to implement. The use of these computational techniques has given surgeons the ability to leverage far more accurate and individualized predictive tools to better inform individual patients regarding predicted outcomes after ASD correction surgery. Applications range from predicting QoL measures to predicting the risk of major complications, hospital readmission, and reoperation rates. In addition, AI has been used to create a novel classification system for ASD patients, which will help surgeons identify distinct patient subpopulations with unique risk-benefit profiles. Overall, these tools will help surgeons tailor their clinical practice to address patients’ individual needs and create an opportunity for personalized medicine within spine surgery.