Bariatric Surgery Before Elective Anterior Cervical Discectomy and Fusion (ACDF) in Obese Patients Is Associated With Reduced Risk of 90-Day Postoperative Complications and Readmissions

Effects of Obesity on Cervical Disc Arthroplasty Complications

OBJECTIVE

High body mass index is a well-established modifiable comorbidity that is known to increase postoperative complications in all types of surgery, including spine surgery. Obesity is increasing in prevalence amongst the general population. As this growing population of obese patients ages, understanding how they faire undergoing cervical disc arthroplasty (CDA) is important for providing safe and effective evidence-based care for cervical degenerative pathology.

METHODS

Our study used the Healthcare Cost and Utilization Project's National Inpatient Sample to assess patients undergoing CDA comparing patient characteristics and outcomes in nonobese patients to obese patients from 2004 to 2014.

RESULTS

Our study found a significant increase in the overall utilization of CDA as a treatment modality (p = 0.012) and a statistically significant increase in obese patients undergoing CDA (p < 0.0001) from 2004 to 2014. Obesity was identified as an independent risk factor associated with increased rates of inpatient neurologic complications (odds ratio [OR], 6.99; p = 0.03), pulmonary embolus (OR, 5.41; p = 0.05), and wound infection (OR, 6.97; p < 0.001) in patients undergoing CDA from 2004 to 2014.

CONCLUSION

In patients undergoing CDA, from 2004 to 2014, obesity was identified as an independent risk factor with significantly increased rates of inpatient neurologic complications, pulmonary embolus and wound infection. Large prospective trials are needed to validate these findings.

Prevalence and Risk Factors for Cervical Adjacent Segment Disease and Analysis of the Clinical Effect of Revision Surgery: A Minimum of 5 Years' Follow-Up

STUDY DESIGN

A retrospective study was performed.

OBJECTIVE

To investigate the prevalence and risk factors for adjacent segment disease (ASD) after anterior cervical discectomy and fusion (ACDF) and the clinical efficacy of revision surgery.

METHOD

A total of 219 patients treated with ACDF were analyzed retrospectively. Demographic characteristics, including age, sex, body mass index (BMI) and bone mineral density (BMD), and radiographic measurements, including C2-C7 cervical sagittal vertical axis (cSVA), T1 slope (T1S), thoracic inlet angle (TIA) and C2-C7 Cobb angle, were analyzed. Modified Japanese Orthopaedic Association (mJOA) score and visual analog scale (VAS) score were used to evaluate patient function. Parameters were analyzed with Student's t test, and potential risk factors for ASD were further analyzed with multivariate logistic regression analysis.

RESULTS

The incidence of ASD after ACDF surgeries was 21%. The severity of osteoporosis, BMI and C2-C7 cSVA were significantly higher in the ASD group than in the NASD group (P < .05). The preoperative and postoperative TIAs were lower in the ASD group (P < .05). Multivariate logistic regression analysis showed that a high BMI, severe osteoporosis and a high C2-C7 cSVA were risk factors for ASD after ACDF (P < .05). The postoperative TIA and postoperative T1S were also correlated with ASD (P < .05).

CONCLUSION

Patients with a high BMI, severe osteoporosis, and a large C2-C7 cSVA after ACDF have a higher risk of ASD, while a large T1S and TIA may be protective factors. In addition, revision surgery can restore cervical spine balance in patients with ASD and promote better clinical outcomes.

Anterior Cervical Discectomy and Fusion Outcomes in Patients With and Without Bariatric Surgery-Weight Loss Does Make a Difference

STUDY DESIGN

A retrospective comparative cohort study.

OBJECTIVE

To compare outcomes of elective non-obese anterior cervical discectomy and fusion (ACDF) patients with those that underwent bariatric surgery (BS).

SUMMARY OF BACKGROUND DATA

Morbid obesity (MO) has been associated with an increased risk of complications following procedures such as elective ACDF. While pre-emptive BS has been considered for those with MO (body mass index [BMI] ≥35 kg/m 2 ), the impact of this intervention on BMI and its resultant correlation with surgical outcomes remains limited.

METHODS

The PearlDiver 2010-Q1 2020 MSpine database was used to identify patients undergoing elective isolated ACDF. Three sub-cohorts were defined as follows: (1) Non-obese controls without a history of BS, (2) patients with BS procedure within two years with a BMI <35 kg/m 2 (BS+MO-), and (3) patients with BS procedure within the two years with a BMI ≥35 kg/m 2 (BS+MO+). Univariate and multivariate regression analyses were performed to compare 90-day adverse event rates adjusting for age, sex, Elixhauser Comorbidity Index, and length of stay. Kaplan-Meier analysis was performed to assess five-year cervical reoperation rates.

RESULTS

Of 160,166 elective ACDF patients, prior BS was identified for 479. Of these, 136 patients were BS+MO- and 343 were BS+MO+. On multivariate analysis, BS+MO- were not at increased odds of adverse events, but BS+MO+ were at greater odds of 90-day pulmonary embolism (odds ratio 3.28, P =0.043), wound dehiscence (5.02, P <0.001), hematomas (2.52, P =0.042), and overall minor adverse events (1.61, P =0.011) compared with controls. Five-year reoperation rates were not significantly different between the groups.

CONCLUSION

Twenty-eight percent of those with BS before ACDF fell out of the categorization of MO. Among this group, the odds of adverse events were similar to non-obese patients. These findings suggest that the psychological preparation and BS alone are insufficient to reduce the risk of adverse events after ACDF. Weight reduction must be achieved as well, ideally moving patients out of the BMI range for morbid obesity.

Clinical Outcomes of Bariatric Surgery Before Spinal Fusion: A Systematic Review

INTRODUCTION

Morbidly obese patients are at increased risk for intraoperative and postoperative complications following spinal fusion. Preoperative weight loss can improve clinical outcomes. The present systematic literature review is aimed to evaluate the hypothesis that bariatric surgery before spinal fusion surgery is associated with higher rates of complications and revisions.

METHODS

Three databases were queried for literature pertaining to bariatric surgery prior to spinal fusion. A 2-author screening process was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Methodologic index for non-randomized studies criteria was used to objectively assess the methodologic quality of the studies reviewed. Retrospective cohort studies in which the patients underwent bariatric surgery were included.

RESULTS

Four retrospective cohort studies consisting of a total of 180,090 patients were included. Length of stay was significantly shorter for the bariatric surgery (BS) group patients than the control (C) groups patients (P = 0.009). There were no significant differences in 1-year mortality rate (P = 1.0), readmission rate (P = 0.86), overall postoperative complications (P = 0.83), and postoperative infections (P = 0.97) between the BS and C groups.

CONCLUSIONS

There were no consistent differences in rates of postoperative complications, infections, hospital readmission, and mortality between obese patients with bariatric surgery prior to spinal fusion and control group patients. The present study does not support the hypothesis that bariatric surgery before spinal fusion contributes to a higher rate of postoperative complications in patients undergoing spinal fusion.

Comparison of Deep Learning and Classical Machine Learning Algorithms to Predict Postoperative Outcomes for Anterior Cervical Discectomy and Fusion Procedures With State-of-the-art Performance

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Due to anterior cervical discectomy and fusion (ACDF) popularity, it is important to predict postoperative complications, unfavorable 90-day readmissions, and two-year reoperations to improve surgical decision-making, prognostication, and planning.

SUMMARY OF BACKGROUND DATA

Machine learning has been applied to predict postoperative complications for ACDF; however, studies were limited by sample size and model type. These studies achieved ≤0.70 area under the curve (AUC). Further approaches, not limited to ACDF, focused on specific complication types and resulted in AUC between 0.70 and 0.76.

MATERIALS AND METHODS

The IBM MarketScan Commercial Claims and Encounters Database and Medicare Supplement were queried from 2007 to 2016 to identify adult patients who underwent an ACDF procedure (N=176,816). Traditional machine learning algorithms, logistic regression, and support vector machines, were compared with deep neural networks to predict: 90-day postoperative complications, 90-day readmission, and two-year reoperation. We further generated random deep learning model architectures and trained them on the 90-day complication task to approximate an upper bound. Last, using deep learning, we investigated the importance of each input variable for the prediction of 90-day postoperative complications in ACDF.

RESULTS

For the prediction of 90-day complication, 90-day readmission, and two-year reoperation, the deep neural network-based models achieved AUC of 0.832, 0.713, and 0.671. Logistic regression achieved AUCs of 0.820, 0.712, and 0.671. Support vector machine approaches were significantly lower. The upper bound of deep learning performance was approximated as 0.832. Myelopathy, age, human immunodeficiency virus, previous myocardial infarctions, obesity, and documentary weakness were found to be the strongest variable to predict 90-day postoperative complications.

CONCLUSIONS

The deep neural network may be used to predict complications for clinical applications after multicenter validation. The results suggest limited added knowledge exists in interactions between the input variables used for this task. Future work should identify novel variables to increase predictive power.

The Impact of Prior Bariatric Surgery on Outcomes After Spine Surgery: A Systematic Review and meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To compare outcomes and complication rates in patients undergoing bariatric surgery (BS) prior to spine surgery.

METHODS

A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines comparing the outcomes of spine surgery between subjects with prior bariatric surgery to those who were considered obese with no prior bariatric surgery.

RESULTS

A total of 183, 570 patients were included in the 4 studies meeting inclusion criteria. The mean patient age was 52.9 years, and the majority were female (68%). The two groups consisted of a total of 36, 876 patients with prior BS and 146, 694 obese patients without prior BS. The overall rate of complications in the prior BS group was 6.4% (4.5%-38.7%) compared to 11.9% (11.2%-55.4%) in the non-prior BS obese group with a statistically significant difference between the two groups. The prior BS group had lower rates of renal, neurological, and thromboembolic complications, with a lower mortality and readmission rate. In a subgroup undergoing cervical spine surgery, patients with prior BS had fewer cardiac, GI, and total complications. For patients undergoing thoracolumbar spine surgery, patients with prior BS had fewer thromboembolic and total complications.

CONCLUSION

Patients undergoing bariatric surgery prior to spine surgery had fewer renal, neurological, and thromboembolic complications as well as a decreased mortality and readmission rate.