Outcome of lumbar spinal fusion surgery in obese patients

Does Body Mass Index Influence Intraoperative Costs and Operative Times for Anterior Cervical Discectomy and Fusion? A Time-Driven Activity-Based Costing Analysis

OBJECTIVE

Spine surgeons are often unaware of drivers of cost variation for anterior cervical discectomy and fusion (ACDF). We used time-driven activity-based costing to assess the relationship between body mass index (BMI), total cost, and operating room (OR) times for ACDFs.

METHODS

Total cost was divided into direct and indirect costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments. Timestamps for all involved personnel and material resources were documented. Total intraoperative costs were estimated for all ACDFs from 2017 to 2022. All patients were categorized into distinct BMI-based cohorts. Linear regression models were performed to assess the relationship between BMI, total cost, and OR times.

RESULTS

A total of 959 patients underwent ACDFs between 2017 and 2022. The average age and BMI were 58.1 ± 11.2 years and 30.2 ± 6.4 kg/m2, respectively. The average total intraoperative cost per case was $7120 ± $2963. Multivariable regression analysis revealed that BMI was not significantly associated with total cost (P = 0.36), supply cost (P = 0.39), or personnel cost (P = 0.20). Higher BMI was significantly associated with increased time spent in the OR (P = 0.018); however, it was not a significant factor for the duration of surgery itself (P = 0.755). Rather, higher BMI was significantly associated with nonoperative OR time (P < 0.001).

CONCLUSIONS

Time-driven activity-based costing is a feasible and scalable methodology for understanding the true intraoperative costs of ACDF. Although higher BMI was not associated with increased total cost, it was associated with increased preparatory time in the OR.

Effects of BMI on SI joint fusion outcomes: examining the evidence to improve insurance guidelines

BACKGROUND CONTEXT

Obesity is increasing. Previous studies have demonstrated an association between obesity and adverse events after lumbar fusion. There is limited evidence on the effect of obesity on minimally invasive SI joint fusion (SIJF) outcomes.

PURPOSE

The purpose of this study was to investigate the impact of obesity on patient-reported outcomes in patients undergoing SIJF surgery using triangular titanium implants (TTI).

STUDY DESIGN

Retrospective cohort study based on four prospective clinical trials (INSITE [NCT01681004], SIFI [NCT01640353], iMIA [NCT01741025], and SALLY [NCT03122899]).

PATIENT SAMPLE

Adult patients ≥18 years of age who underwent minimally invasive surgery (MIS) sacroiliac joint (SIJ) fusion between 2012 and 2021.

OUTCOME MEASURES

Visual analog scale (VAS Pain), Oswestry Disability Index (ODI).

METHODS

Participants were classified using the National Institutes of Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects underwent either minimally invasive SIJ fusion with TTI or nonsurgical management (INSITE and iMIA studies only). All subjects completed SIJ pain scale scores (measured with a 100-point VAS) and disability scores (measured with ODI) at baseline and at scheduled visits to 24 months. Repeated measures analysis of variance was used to examine the impact of BMI category on score changes.

RESULTS

In the SIJF group, mean SIJ pain improved at 24 months by 53.3 points (p<.0001). Over the 24-month follow-up period, BMI category did not impact mean improvement in SIJ pain scale score (repeated measures analysis of variance (ANOVA) p=.44). In the SIJF group, mean ODI at 24 months improved by 25.8 points (p<.0001). BMI category did not impact mean improvement in ODI (ANOVA p=.60). In the nonsurgical management (NSM) group, mean improvements in SIJ pain scale and ODI were clinically small (8.7 and 5.2 points, respectively) and not affected by BMI category (ANOVA p=.49 and .40).

CONCLUSION

This study demonstrates similar benefits and risks of minimally invasive SIJ fusion with TTI across all BMI categories. This analysis suggests that obese patients benefit from minimally invasive SIJ fusion and should not be denied this procedure based solely on elevated BMI.

Body mass index is not associated with time on veno-venous extracorporeal membrane oxygenation or in-hospital mortality

Morbid obesity, as characterized by BMI, is often utilized as an exclusion criterion for VV-ECMO because of presumed poor prognosis and technically complex cannulation. However, the "obesity paradox" suggests obesity may be protective during critical illness, and BMI does not capture variations in body type, adiposity, or fluid balance. This study examines relationships between BMI and patient outcomes. Adult VV-ECMO patients with BMI ≥ 35 kg/m2 admitted January 2012 to June 2021 were identified from an institutional registry. BMI and outcomes were analyzed with Mann-Whitney U tests and Pearson correlations with Bayesian post-hoc analyses. 116 of 960 ECMO patients met inclusion criteria. Median (Q1, Q3) BMI was 42.3 (37.3, 50.8) and min, max of 35.0, 87.8 with 9.0 (5.0, 15.5) ECMO days. BMI was not significantly correlated with ECMO days (r = -0.102; p = .279). Bayesian analyses showed moderate evidence against BMI correlating with ECMO days. In-hospital mortality (27%) was significantly associated with ECMO days (p = .014) but not BMI (p = .485). In this cohort of high-BMI patients, BMI was not associated with survival or time on ECMO. BMI itself should not be used as an exclusion criterion for VV-ECMO.

Is Routine Use of Drain Really Necessary for Posterior Lumbar Interbody Fusion Surgery? A Retrospective Case Series with a Historical Control Group

STUDY DESIGN

A retrospective case-control study.

OBJECTIVES

The usefulness of a drain in spinal surgery has always been controversial. The purposes of this study were to determine the incidence of hematoma-related complications after posterior lumbar interbody fusion (PLIF) without a drain and to evaluate its usefulness.

METHODS

We included 347 consecutive patients with degenerative lumbar disease who underwent single- or double-level PLIF. The participants were divided into 2 groups by the use of a drain or not; drain group and no-drain group.

RESULTS

In 165 cases of PLIF without drain, there was neither a newly developed neurological deficit due to hematoma nor reoperation for hematoma evacuation. In the no-drain group, there were 5 (3.0%) patients who suffered from surgical site infection (SSI), all superficial, and 17 (10.3%) patients who complained of postoperative transient recurred leg pain, all treated conservatively. Days from surgery to ambulation and length of hospital stay (LOS) of the no-drain group were faster than those of the drain group (P < 0.001). In a multiple regression analysis, a drain insertion was found to have a significant effect on the delayed ambulation and increased LOS. No significant differences existed between the 2 groups in additional surgery for hematoma evacuation, or SSI.

CONCLUSIONS

No hematoma-related neurological deficits or reoperations caused by epidural hematoma and SSI were observed in the no-drain group. The no-drain group did not show significantly more frequent postoperative complications than the drain use group, hence the routine insertion of a drain following PLIF should be reconsidered carefully.

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.

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.

Rheumatoid Arthritis in Spine Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic Review and Meta-analysis.

OBJECTIVE

The purpose of this study is to synthesize recommendations for perioperative medical management of RA patients and quantify outcomes after spine surgery when compared to patients without RA.

METHODS

A search of available literature on patients with RA and spine surgery was performed. Studies were included if they provided a direct comparison of outcomes between patients undergoing spine surgery with or without RA diagnosis. Meta-analysis was performed on operative time, estimated blood loss, hospital length of stay, overall complications, implant-related complications, reoperation, infection, pseudarthrosis, and adjacent segment disease.

RESULTS

Included in the analysis were 9 studies with 703 patients with RA undergoing spine surgery and 2569 patients without RA. In RA patients compared to non-RA patients undergoing spine surgery, the relative risk of infection was 2.29 times higher (P = .036), overall complications 1.61 times higher (P < .0001), implant-related complications 3.93 times higher (P = .009), and risk of reoperation 2.45 times higher (P < .0001). Hospital length of stay was 4.6 days longer in RA patients (P < .0001).

CONCLUSIONS

Treatment of spinal pathology in patients with RA carries an increased risk of infection and implant-related complications. Spine-specific guidelines for perioperative management of antirheumatic medication deserve further exploration. All RA patients should be perioperatively co-managed by a rheumatologist. This review helps identify risk profiles in RA specific to spine surgery and may guide future studies seeking to medically optimize RA patients perioperatively.

Obesity and Spine Surgery: A Qualitative Review About Outcomes and Complications. Is It Time for New Perspectives on Future Researches?

STUDY DESIGN

Literature review.

OBJECTIVES

An increasing number of obese patients requires operative care for degenerative spinal disorders. The aim of this review is to analyze the available evidence regarding the role of obesity on outcomes after spine surgery. Peri-operative complications and clinical results are evaluated for both cervical and lumbar surgery. Furthermore, the contribution of MIS techniques for lumbar surgery to play a role in reducing risks has been analyzed.

METHODS

Only articles published in English in the last 10 years were reviewed. Inclusion criteria of the references were based on the scope of this review, according to PRISMA guidelines. Moreover, only paper analyzing obesity-related complications in spine surgery have been selected and thoroughly reviewed. Each article was classified according to its rating of evidence using the Sacket Grading System.

RESULTS

A total number of 1636 articles were found, but only 130 of them were considered to be relevant after thorough evaluation and according to PRISMA checklist. The majority of the included papers were classified according to the Sacket Grading System as Level 2 (Retrospective Studies).

CONCLUSION

Evidence suggest that obese patients could benefit from spine surgery and outcomes be satisfactory. A higher rate of peri-operative complications is reported among obese patients, especially in posterior approaches. The use of MIS techniques plays a key role in order to reduce surgical risks. Further studies should evaluate the role of multidisciplinary counseling between spine surgeons, nutritionists and bariatric surgeons, in order to plan proper weight loss before elective spine surgery.

Impact of Sarcopenia and Bone Mineral Density on Implant Failure after Dorsal Instrumentation in Patients with Osteoporotic Vertebral Fractures

Background and Objectives: Age-related loss of bone and muscle mass are signs of frailty and are associated with an increased risk of falls and consecutive vertebral fractures. Management often necessitates fusion surgery. We determined the impacts of sarcopenia and bone density on implant failures (IFs) and complications in patients with spondylodesis due to osteoporotic vertebral fractures (OVFs). Materials and Methods: Patients diagnosed with an OVF according to the osteoporotic fracture classification (OF) undergoing spinal instrumentation surgery between 2011 and 2020 were included in our study. The skeletal muscle area (SMA) was measured at the third lumbar vertebra (L3) level using axial CT images. SMA z-scores were calculated for the optimal height and body mass index (BMI) adjustment (zSMA_HT). The loss of muscle function was assessed via measurement of myosteatosis (skeletal muscle radiodensity, SMD) using axial CT scans. The bone mineral density (BMD) was determined at L3 in Hounsfield units (HU). Results: A total of 68 patients with OVFs underwent instrumentation in 244 segments (mean age 73.7 ± 7.9 years, 60.3% female). The median time of follow-up was 14.1 ± 15.5 months. Sarcopenia was detected in 28 patients (47.1%), myosteatosis in 45 patients (66.2%), and osteoporosis in 49 patients (72%). The presence of sarcopenia was independent of chronological age (p = 0.77) but correlated with BMI (p = 0.005). The zSMA_HT was significantly lower in patients suffering from an IF (p = 0.0092). Sarcopenia (OR 4.511, 95% CI 1.459–13.04, p = 0.0092) and osteoporosis (OR 9.50, 95% CI 1.497 to 104.7, p = 0.014) increased the likelihood of an IF. Using multivariate analysis revealed that the zSMA_HT (p = 0.0057) and BMD (p = 0.0041) were significantly related to IF occurrence. Conclusion: Herein, we established sarcopenic obesity as the main determinant for the occurrence of an IF after instrumentation for OVF. To a lesser degree, osteoporosis was associated with impaired implant longevity. Therefore, measuring the SMA and BMD using an axial CT of the lumbar spine might help to prevent an IF in spinal fusion surgery via early detection and treatment of sarcopenia and osteoporosis.

Complications of Spine Surgery in "Super Obese" Patients

STUDY DESIGN

Retrospective chart review with matched control.

OBJECTIVE

To evaluate the indications and complications of spine surgery on super obese patients.

METHODS

A retrospective review assessed super obese patients undergoing spine surgery at a level-1 trauma and spine referral center from 2012 to 2016. Outcomes were compared to age-matched controls with body mass index (BMI) <50 kg/m². The control group was further subdivided into patients with BMI <30 kg/m² (normal) and BMI between 30 and 50 kg/m² (obese).

RESULTS

Sixty-three super obese patients undergoing 86 surgeries were identified. Sixty patients (78 surgeries) were in the control group. Age and number of elective versus nonelective cases were not significantly different. Mean BMI of the super obese group was 55 kg/m² (range 50-77 kg/m²) versus 29 kg/m² in the controls (range 20-49 kg/m²). Fifty-two percent of surgeries were elective, and the most common indication was degenerative disease (39%). Compared with controls, super obese patients had a higher complication rate (30% [n = 19] vs 10% [N = 6], P = .0055) but similar 30-day mortality rate (5% vs 5%), a finding that was upheld when comparing super obese with each of the control group stratifications (BMI 30-50 and BMI <30 kg/m²). The most common complication among super obese patients was wound dehiscence/infection (n = 8, 13%); 2 patients' surgeries were aborted. Complication rates for elective surgery were 21% (n = 7) for super obese patients and 4% (n = 1) for controls (P = .121); complication rates for nonelective procedures were 40% (n = 12) and 14% (n = 5), respectively (P = .023).

CONCLUSION

The complication rate of spine surgery in super obese patients (BMI ≥ 50 kg/m²) is significantly higher than other patients, particularly for nonelective cases.

Comparison of Perioperative and Postoperative Outcomes of Minimally Invasive and Open TLIF in Obese Patients: A Systematic Review and Meta‑Analysis

PURPOSE

Previous studies have demonstrated that minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) is comparable to the open approach in terms of efficacy and safety. However, few comparative studies of surgical procedures in patients with obesity show that they may react differently to open-TLIF (O-TLIF) and MI-LTIF approaches.

PATIENTS AND METHODS

The main indicators were complications, visual analog scale (VAS) score, and Oswestry Disability Index (ODI) score, and secondary indicators were operative time, blood loss, and hospital stay.

RESULTS

No significant differences in the VAS and ODI scores for back pain at the last follow-up and wound infection rates were observed between the two groups. Dural tear incidence and complication rate were significantly lower in the MI-TLIF group than that in the O-TLIF group (P = 0.002 and 0.001, respectively). No significant difference in operative time was found between the two groups. There was less blood loss and shorter hospital stay (P = 0.001 and 0.002, respectively) in the MI-TLIF group than that in the O-TLIF group.

CONCLUSION

Compared with O-TLIF, MI-TLIF is an effective and safe surgical option for patients with obesity, which resulted in similar improvements in pain and functional disability, as well as a lower complication rate.

Perioperative Predictive Factors for Positive Outcomes in Spine Fusion for Adult Deformity Correction

Purpose: Identifying perioperative factors that may influence the outcomes of long spine fusion for the treatment of adult deformity is key for tailored surgical planning and targeted informed consent. The aim of this study was to analyze the association between demographic or perioperative factors and clinical outcomes 2 years after long spine fusion for the treatment of adult deformity. Methods: This study is a multivariate analysis of retrospectively collected data. All patients who underwent long fusion of the lumbar spine for adult spinal deformity (January 2016–June 2019) were included. The outcomes of interest were the Oswestry disability index (ODI), visual analogic scale (VAS) preoperatively and at 1 and 2 years’ follow up, age, body mass index, American Society of Anaesthesiologists (ASA) score, upper and lowest instrumented vertebrae (UIV and LIV, respectively), length of surgery, estimated blood loss, and length of hospital stay. Results: Data from 192 patients were available. The ODI at 2 years correlated weakly to moderately with age (r = 0.4), BMI (r = 0.2), ASA (r = 0.3), and LIV (r = 0.2), and strongly with preoperative ODI (r = 0.6). The leg VAS at 2 years moderately correlated with age (r = 0.3) and BMI (r = 0.3). Conclusion: ODI and VAS at 2 years’ follow-up had no to little association to preoperative age, health status, LIV, or other peroperative data, but showed a strong correlation with preoperative ODI and pain level.

The Influence of Baseline Clinical Status and Surgical Strategy on Early Good to Excellent Result in Spinal Lumbar Arthrodesis: A Machine Learning Approach

The study aims to create a preoperative model from baseline demographic and health-related quality of life scores (HRQOL) to predict a good to excellent early clinical outcome using a machine learning (ML) approach. A single spine surgery center retrospective review of prospectively collected data from January 2016 to December 2020 from the institutional registry (SpineREG) was performed. The inclusion criteria were age ≥ 18 years, both sexes, lumbar arthrodesis procedure, a complete follow up assessment (Oswestry Disability Index-ODI, SF-36 and COMI back) and the capability to read and understand the Italian language. A delta of improvement of the ODI higher than 12.7/100 was considered a "good early outcome". A combined target model of ODI (Δ ≥ 12.7/100), SF-36 PCS (Δ ≥ 6/100) and COMI back (Δ ≥ 2.2/10) was considered an "excellent early outcome". The performance of the ML models was evaluated in terms of sensitivity, i.e., True Positive Rate (TPR), specificity, i.e., True Negative Rate (TNR), accuracy and area under the receiver operating characteristic curve (AUC ROC). A total of 1243 patients were included in this study. The model for predicting ODI at 6 months' follow up showed a good balance between sensitivity (74.3%) and specificity (79.4%), while providing a good accuracy (75.8%) with ROC AUC = 0.842. The combined target model showed a sensitivity of 74.2% and specificity of 71.8%, with an accuracy of 72.8%, and an ROC AUC = 0.808. The results of our study suggest that a machine learning approach showed high performance in predicting early good to excellent clinical results.

Characteristics of Tc-MEP Waveforms in Spine Surgery for Patients with Severe Obesity

STUDY DESIGN

Prospective multicenter study.

OBJECTIVE

The aim of this study was to evaluate transcranial motor evoked potential (Tc-MEP) waveform monitoring in spinal surgery for patients with severe obesity.

SUMMARY OF BACKGROUND DATA

Spine surgeries in obese patients are associated with increased morbidity and mortality. Intraoperative Tc-MEP monitoring can identify neurologic deterioration during surgery, but has not been examined for obese patients.

METHODS

The subjects were 3560 patients who underwent Tc-MEP monitoring during spine surgery at 16 centers. Tc-MEPs were recorded from multiple muscles via needle or disc electrodes. A decrease in Tc-MEP amplitude of ≥70% from baseline was used as an alarm during surgery. Preoperative muscle weakness with manual muscle test (MMT) grade ≤4 was defined as a motor deficit, and a reduction of one or more MMT grade postoperatively was defined as deterioration.

RESULTS

The 3560 patients (1698 males, 47.7%) had a mean age of 60.0 ± 20.3 years. Patients with body mass index >35 kg/m2 (n = 60, 1.7%) were defined as severely obese. Compared with all other patients (controls), the rates of preoperative motor deficit (41.0% vs. 29.6%, P < 0.05) and undetectable baseline waveforms in all muscles were significantly higher in the severely obese group (20.0% vs. 1.7%, P < 0.01). Postoperative motor deterioration did not differ significantly between the groups. The sensitivity and specificity of the alarm criterion for prediction of postoperative neurologic complications were 75.0% and 83.9% in severely obese patients and 76.4% and 89.6% in controls, with no significant difference between the groups.

CONCLUSION

Tc-MEPs can be used in spine surgery for severely obese cases to predict postoperative motor deficits, but the rate of undetectable waveforms is significantly higher in such cases. Use of a multichannel waveform approach or multiple modalities may facilitate safe completion of surgery. Waveforms should be carefully evaluated and an appropriate rescue procedure is required if the alarm criterion occurs.Level of Evidence: 3.

The Effect of Morbid Obesity on Complications, Readmission, and Patient-Reported Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion: An Inverse Propensity Score Weighted Analysis

STUDY DESIGN

Retrospective review of prospectively collected data at a single institution.

OBJECTIVE

To compare perioperative and clinical outcomes in morbidly obese patients who underwent minimally invasive transforaminal lumbar interbody fusion (MiTLIF).

SUMMARY OF BACKGROUND DATA

Obesity remains a serious public health concern. Obese patients who undergo lumbar fusion have historically thought to be at higher risk for complications and fare worse regarding quality-of-life outcomes. However, recent literature may demonstrate comparable risk and outcomes in obese patients. An increasing number of patients are categorized as morbidly obese (body mass index [BMI] ≥ 40 kg/m2). Perioperative and patient-reported outcomes (PROs) are lacking in this patient population.

METHODS

The authors retrospectively reviewed a prospectively collected database of all morbidly obese and non-obese patients that underwent MiTLIF between 2015 and 2018 for degenerative conditions who had minimum 1-year follow-up for outcome assessment. An inverse propensity/probability of treatment weighting was utilized to create a synthetic weighted sample in which covariates were independent of obesity designation to adjust for imbalance between groups. Generalized estimating equations (GEE) was used to estimate the association of morbid obesity and complications and 1-year PROs.

RESULTS

A total of 292 patients were analyzed with 234 non-obese patients and 58 morbidly obese patients. Multivariate analysis failed to demonstrate any association between morbid obesity and achieving minimal clinically important difference (MCID) for Oswestry disability index (ODI), visual analog scale (VAS), or short form-12 (SF-12) physical component score. However, morbid obesity was associated with significant decrease in odds of achieving MCID for SF-12 mental component score (P = 0.001). Increased surgery duration was significantly associated with morbid obesity (P = 0.001). Morbid obesity exhibited no statistically significant association with postoperative complications, readmission, pseudarthrosis, or adjacent segment disease (ASD).

CONCLUSION

Morbidly obese patients who undergo MiTLIF can achieve meaningful clinical improvement comparable to nonobese patients. Morbid obesity was associated with longer surgical times but was not associated with postoperative complications, readmission, or ASD.Level of Evidence: 3.

The Influence of Body Mass Index in Obese and Morbidly Obese Patients on Complications and 30- and 90-day Readmissions Following Lumbar Spine Fusion

STUDY DESIGN

Retrospective cohort study using the 2013-2017 National Readmission Database.

OBJECTIVE

The aim of this study was to quantify the influence of body mass index (BMI) on complication and readmission rates following lumbar spine fusion.

SUMMARY OF BACKGROUND DATA

Compared to controls, patients with BMI ≥35 had greater odds of readmission, infection, and wound complications following lumbar spine fusion.

METHODS

Patients who underwent elective lumbar spine fusion within the population-based sample were considered for inclusion. Exclusion criteria included nonelective lumbar spine fusions, malnourished, anorexic, or underweight patients, and surgical indications of trauma or neoplasm. Patients were grouped by BMI: 18.5 to 29.9 (controls), 30 to 34.9 (obesity I), 35 to 39.9 (obesity II), and ≥40 (obesity III). Multivariate regression was performed to analyze differences in complications and readmissions between groups. Predictive modeling was conducted to estimate the impact of BMI on 30- and 90-day infection, wound complication, and readmissions rates.

RESULTS

A total of 86,697 patients were included for analysis, with an average age of 58.9 years and 58.9% being female. The obesity II group had significantly higher odds of infection (odds ratio [OR]: 1.82, 95% confidence interval [CI]: 1.28-2.62, P = 0.001), wound dehiscence (OR: 3.08, 95% CI: 1.70-6.18, P = 0.0006), and 30-day readmission (OR: 1.32, 95% CI: 1.11-1.58, P = 0.002), whereas the obesity III group had significantly higher odds of acute renal failure (OR: 2.14, 95% CI: 1.20-4.06, P = 0.014), infection (OR: 2.43, 95% CI: 1.72-3.48, P < 0.0001), wound dehiscence (OR: 3.76, 95% CI: 2.08-7.51, P < 0.0001), 30-day readmission (OR: 1.62, 95% CI: 1.36-1.93, P < 0.0001), and 90-day readmission (OR: 1.53, 95% CI: 1.31-1.79, P < 0.0001) compared with controls. Predictive modeling showed cumulative increases of 6.44% in infection, 3.69% in wound dehiscence, and 1.35% in readmission within 90-days for each successive BMI cohort.

CONCLUSION

Progressively higher risks for infection, wound complications, and hospital readmission were found with each progressive BMI level.Level of Evidence: 3.

The Impact of Obesity on Risk Factors for Adverse Outcomes in Patients Undergoing Elective Posterior Lumbar Spine Fusion

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

The aim of this study was to determine the influence of obesity on risk factors for adverse outcome after lumbar spine fusion (LSF).

SUMMARY OF BACKGROUND DATA

Obesity is risk factor for complications after LSF and poses unique challenges regarding optimization of care. Nonetheless, this patient population is not well-studied.

METHODS

Adult patients undergoing LSF were identified the State Inpatient Database. Patients were identified as obese or nonobese using ICD-9 codes. Outcome variables were 90-day readmission, major medical complication, infection, and revision rates. Data were queried for demographics, comorbidities, surgery characteristics, and outcome variables. Logistic multivariate regression was utilized, serially testing interactions between obesity and other independent variables in separate models for each outcome. The Benjamini-Hochberg procedure was used to adjust statistical significance for multiple comparisons.

RESULTS

A total of 262,153 patients were included: 31,062 obese and 231, 091 nonobese. For major complications, obese patients had lower odds ratios (ORs) versus nonobese patients for cerebrovascular accident, diabetes with chronic complications, age ≥65, congestive heart failure, history of myocardial infarction, renal disease, chronic pulmonary disease, Medicare/Medicaid payor, more than two levels fused, transforaminal/posterior lumbar interbody fusion, and female sex, and higher OR for non-White race. For readmission, obese patients had lower OR for age ≥65, history of MI, renal disease, and mental health disease, and higher OR for female sex. For revision, obese patients had higher OR for female sex and TLIF/PLIF. For infection, obese patients had lower OR for diabetes with and without chronic complications, and higher OR for female sex.

CONCLUSION

Many medical comorbidities have less impact in obese patients than nonobese patients in predicting adverse outcomes despite increased rates of adverse outcomes in obese patients. These findings reflect the impact of obesity as an independent risk factor and have important implications for preoperative optimization.Level of Evidence: 3.

Outcome of non-instrumented lumbar spinal surgery in obese patients: a systematic review

INTRODUCTION

Lumbar spinal decompression procedures are well known in their techniques and outcomes. However, outcomes of lumbar spinal surgery in patients with obesity are relatively unknown. The aim of this review is to assess the effect of obesity on post-operative outcomes of lumbar non-instrumented decompressive spinal surgery.

METHODS AND MATERIALS

A literature search through PubMed, Embase, Web of Science and Cochrane was performed. Articles were included if they reported outcomes of obese patients after non-instrumented lumbar decompression surgery, if these outcomes were described using patient-reported outcome measures and if there was at least two months of follow-up. Risk of bias was assessed using an adjusted version of the Cowley score.

RESULTS

From the 222 unique articles, 14 articles, comprising 13,653 patients, met the inclusion criteria. Eight out of 14 studies had a low risk of bias, while the remaining six had an intermediate risk of bias. Thirteen studies evaluated leg and back pain, and the vast majority demonstrated less decrease in pain in the obese group. Six studies evaluated disability and all but one showed less improvement in obese patients. Five studies evaluated functionality and wellbeing and all but one showed less satisfactory outcome in obese patients.

CONCLUSIONS

Literature does not reveal a difference in clinical outcome nor in complications in patients undergoing non-instrumented lumbar surgery with a BMI lower than 30 or equal to or higher than 30. This may be used by physicians to inform patients prior to lumbar decompression surgery.

[Research progress in effect of obesity on the effectiveness of posterior lumbar fusion]

Objective

To review the effect of obesity on the effectiveness of posterior lumbar fusion in patients with lumbar degenerative diseases (LDD).

Methods

The related literature at home and abroad was extensively reviewed. And the difficulty of operation, risk of complications, and long-term effectiveness of posterior lumbar fusion for obese patients with LDD were summarized.

Results

Although some relevant literature suggest that the posterior lumbar fusion for obese patients is difficult and the risk of postoperative complications is high, the overall research results do not suggest that obesity is a risk factor for the implementation of posterior lumbar fusion. By assessing the physical condition of patients and strictly grasping the surgical indications, obese patients can obtain good surgical efficacy.

Conclusion

Posterior lumbar fusion is an effective method for the treatment of LDD in obese patients. However, relevant studies need to be completed to further evaluate the safety and efficacy of posterior lumbar fusion for obese patients.

Complications and outcomes of open posterior lumbar spinal fusion surgery in obese patients: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether obesity affects the operation, complications and outcomes after open posterior lumbar spinal fusion surgery for the treatment of low back pain and leg pain.

METHODS

A meta-analysis of studies that compared the outcome of posterior lumbar spinal fusion in obese and non-obese patients. A total of 16 studies were included.

RESULTS

There was no difference in pain and functional outcomes. Posterior lumbar spinal fusion in obese patients resulted in a statistically significant increase in intra-operative blood loss (weighted mean difference 40.93, 95% confidence interval (CI) 15.97-65.90, n = 243, and p=.001), longer duration of surgery (weighted mean difference -1.64, 95% CI -4.12 to 0.84, n = 1460, and p=.19), more complications (odds ratio: 1.59, 95% CI 1.24-2.05, n = 339, and p<.001) and extend length of stay (weighted mean difference 0.31, 95% CI 0.07-0.55, n = 1408, and p=.01).

CONCLUSIONS

Obese patients experience more blood loss, longer duration of surgery, more complications and extended length of stay, but their back and leg pain and functional outcomes are similar to non-obese patients. Based on these results, obesity is not a contraindication to open posterior lumbar spinal fusion surgery.

Impact of Obesity on Complication Rates, Clinical Outcomes, and Quality of Life after Minimally Invasive Transforaminal Lumbar Interbody Fusion

BACKGROUND

 Percutaneous pedicle screw fixation in obese patients remains a surgical challenge. We aimed to compare patient-reported outcomes and complication rates between obese and nonobese patients who were treated by minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

METHODS

 The authors retrospectively reviewed patients who underwent MIS-TLIF at a single institution between 2011 and 2014. Patients were classified as obese (body mass index [BMI] ≥30 kg/m²) or nonobese (BMI < 30 kg/m²), according to their BMI. Outcomes assessed were complications, numerical rating scale (NRS) scores for back and leg pain, Oswestry Disability Index (ODI), and 36-Item Short-Form Survey (SF-36) scores.

RESULTS

 The final study group consisted of 71 patients, 24 obese (33.8%, 34.8 ± 3.8 kg/m²) and 47 nonobese (66.2%, 25.4 ± 2.9 kg/m²). Instrumentation failures (13.6 vs. 17.0%), dural tears (17.2 vs. 4.0%), and revision rates (16.7 vs. 19.1%) were similar between both groups (p > 0.05). Perioperative improvements in back pain (4.3 vs. 5.4, p = 0.07), leg pain (3.8 vs. 4.2, p = 0.6), and ODI (13.3 vs. 22.5, p = 0.5) were comparable among the groups and persisted at long-term follow-up. Obese patients had worse postoperative physical component SF-36 scores than nonobese patients (36.4 vs. 42.7, p = 0.03), while the mental component scores were not statistically different (p = 0.09).

CONCLUSION

 Obese patients can achieve similar improvement of the pain intensity and functional status even at long-term follow-up. In patients with appropriate surgical indications, obesity should not be considered a contraindication for MIS-TLIF surgery.

Long-term impact of obesity on patient-reported outcomes and patient satisfaction after lumbar spine surgery: an observational study

OBJECTIVE

Obese body habitus is a challenging issue to address in lumbar spine surgery. There is a lack of consensus on the long-term influence of BMI on patient-reported outcomes and satisfaction. This study aimed to examine the differences in patient-reported outcomes over the course of 12 and 24 months among BMI classifications of patients who underwent lumbar surgery.

METHODS

A search was performed using the Quality Outcomes Database (QOD) Spine Registry from 2012 to 2018 to identify patients who underwent lumbar surgery and had either a 12- or 24-month follow-up. Patients were categorized based on their BMI as normal weight (≤ 25 kg/m2), overweight (25-30 kg/m2), obese (30-40 kg/m2), and morbidly obese (> 40 kg/m2). Outcomes included the Oswestry Disability Index (ODI) and the visual analog scale (VAS) for back pain (BP) and leg pain (LP), and patient satisfaction was measured at 12 and 24 months postoperatively.

RESULTS

A total of 31,765 patients were included. At both the 12- and 24-month follow-ups, those who were obese and morbidly obese had worse ODI, VAS-BP, and VAS-LP scores (all p < 0.01) and more frequently rated their satisfaction as "I am the same or worse than before treatment" (all p < 0.01) compared with those who were normal weight. Receiver operating characteristic curve analysis revealed that the BMI cutoffs for predicting worsening disability and surgery dissatisfaction were 30.1 kg/m2 and 29.9 kg/m2 for the 12- and 24-month follow-ups, respectively.

CONCLUSIONS

Higher BMI was associated with poorer patient-reported outcomes and satisfaction at both the 12- and 24-month follow-ups. BMI of 30 kg/m2 is the cutoff for predicting worse patient outcomes after lumbar surgery.

Does Rheumatoid Arthritis Affect the Infection and Complications Rates of Spinal Surgery? A Systematic Review and Meta-Analysis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that produces synovial membrane inflammation and causes progressive articular damage with function loss. Some controversy exists regarding whether RA is associated with infection and complications after spinal surgery. The present study aimed to determine the effect of RA on spinal surgery infection and complications.

METHODS

A systematic literature search was performed in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. All studies that had compared patients who had undergone spinal surgery with and without RA were included in the analysis.

RESULTS

We found significantly greater rates statistically of complications (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.20-1.70; P < 0.05) and infections (OR, 1.69; 95% CI, 1.46-1.95, P < 0.05) in those with RA than in those without RA after spinal surgery. When registry data were excluded, the results suggested that the incidence of complications (OR, 2.24; 95% CI, 0.92-5.44; P = 0.08) and infections (OR, 1.76; 95% CI, 1.50-2.07; P < 0.05) was still greater for the RA group than for the non-RA group.

CONCLUSION

When undergoing spinal surgery, patients with RA have a greater risk of operative complications and infection. Surgeons should be aware of these risks and appropriately plan spinal operation for patients with RA to reduce the risk of complications.

Comparison of the Pull-Out Strength between a Novel Micro-Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine

OBJECTIVE

This study aimed to investigate the strength of a novel micro-dynamic pedicle screw by comparing it to the traditional pedicle screw.

METHODS

Forty-five lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows (traditional group vs micro-dynamic group): 15 vertebrae underwent instant pull-out testing; 15 vertebrae underwent 5000-cyclic fatigue loading testing; and 15 vertebrae underwent 10,000-cyclic fatigue loading testing and micro-computed tomography (micro-CT) scanning. The peek pull-out force and normalized peek pull-out force after instant pull-out testing, 5000-cyclic and 10,000-cyclic fatigue loading testing were recorded to estimate the resistance of two types of screws. Bone mineral density was recorded to investigate the strength of the different screws in osteoporotic patients. And the semidiameter of the screw insertion area on micro-CT images after fatigue were compared to describe the performance between screw and bone surface.

RESULTS

The bone mineral density showed a weak correlation with peek pull-out force (r = 0.252, P = 0.024). The peek pull-out force of traditional pedicle screw after 10,000-cyclic fatigue loading were smaller than that of instant pull-out test in both osteoporotic (P = 0.017) and healthy group (P = 0.029), the peek pull-out force of micro-dynamic pedicle screw after 10,000-cyclic fatigue loading was smaller than that in instant pull-out test in osteoporotic group (P = 0.033), but no significant difference in healthy group (P = 0.853). The peek pull-out force in traditional group and micro-dynamic group underwent instant pull-out testing (P = 0.485), and pull-out testing after 5000-cyclic fatigue loading testing (P = 0.184) did not show significant difference. However, the peek pull-out force in micro-dynamic group underwent pull-test after 10,000-cyclic fatigue loading testing was significantly greater than that measured in traditional group (P = 0.005). The normalized peek pull-out force of traditional groups underwent instant pull-out testing, pull-out test after 5000-cyclic and 10,000-cyclic fatigue loading testing significantly decreased as the number of cycles increased (P < 0.001); meanwhile, the normalized peek pull-out force of micro-dynamic groups remained consistent regardless of the number of cycles (P = 0.133). The semidiameter after the fatigue loading test of the traditional screw insertion area was significantly larger than that of the micro-dynamic screw insertion area (P = 0.013).

CONCLUSION

The novel micro-dynamic pedicle screw provides stronger fixation stability in high-cyclic fatigue loading and non-osteoporotic patients versus the traditional pedicle screw, but similar resistance in low-cycle fatigue testing and osteoporotic group vs the traditional pedicle screw.

Minimally Invasive Spine Lumbar Surgery in Obese Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Transforaminal lumbar interbody fusion (TLIF) is the treatment of choice for lumbar spinal stenosis and spondylolisthesis. The procedure can be performed through a traditional open approach (O-TLIF) or through minimally invasive techniques (MI-TLIF). Spinal surgeries in obese patients can pose risks, including increased rates of infection and thromboembolic events.

QUESTIONS/PURPOSES

We sought to systematically review the literature on the differences between MI-TLIF and O-TLIF in the obese patient in terms of complication rate, functional outcomes, blood loss, and length of hospital stay.

METHODS

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to systematically search PubMed, Embase, Web of Science, and the Cochrane Library for studies published through February 2019 and identified those comparing the outcomes of O-TLIF and MI-TLIF in obese patients. The primary outcome was complication rate (total, infections, dural tears); secondary outcomes were blood loss, length of hospital stay, and functional scores. Two authors independently reviewed the studies using the Newcastle-Ottawa Scale, and data were pooled using the Mantel-Haenszel random-effects model.

RESULTS

In the sample of 430 patients, the average age was 53.5 years, there were 153 men and 203 women, and the average body mass index was 33.6. Complications were significantly higher in O-TLIF than in MI-TLIF (OR = 0.420 [95% CI: 0.199, 0.887]; I ² = 45.20%). No difference was detected between the two groups for visual analog scale back pain scores and Oswestry Disability Index scores between the pre-operative and last follow-up visits (SMD = -0.034 [95% CI -0.695, 0.627]; I ² = 62.14% and SMD = 0.617 [95% CI: -1.082, 2.316]; I ² = 25%, respectively). Blood loss was significantly lower in MI-TLIF compared to O-TLIF (SMD = -426.736 [95% CI: -490.720, -362.752]; I ² = 70.53%), as was the duration of hospital stay (SMD = -1.079 [95% CI: -1.591, -0.208]; I ² = 84.3%).

CONCLUSION

MI-TLIF has equivalent efficacy to O-TLIF in obese patients at long-term follow-up. In addition, complication rate, blood loss, and length of hospital stay were lower in MI-TLIF than in O-TLIF.

Complexities of spine surgery in obese patient populations: a narrative review

The obese population is particularly challenging to the spine surgeon in all phases of care. A narrative literature review was performed to review difficulties in spine surgery on the obese patient population and techniques for mitigation. We specifically aimed to assess several topics with regard to this population: patient selection and preoperative care; intraoperative and surgical techniques; and postoperative care, outcomes, and complications. The literature review demonstrated that obese patients are at increased surgical risk with spine surgery due to a variety of factors at all stages of intervention. Preoperatively, obese patients have worse outcomes with physical therapy and present technical difficulties for injections. Transport to a hospital, imaging, resuscitation, and intubation are all challenged by increased body habitus. Intraoperatively, obese patients have increased operative times, blood loss, surgical site infections, and nerve palsies. Patient positioning and intraoperative imaging may be limited. Surgery itself may be technically challenging due to body habitus and minimally invasive techniques are becoming more prevalent in this population. Postoperatively, several studies demonstrate that obese patients have inferior outcomes compared with nonobese counterparts. Patient selection is a key for elective interventions, and appropriate infrastructure aids in the ultimate outcomes for both elective and nonelective surgical treatments. Overall, obese patients present several challenges to the spine surgeon, and certain precautions can be undertaken preoperatively, intraoperatively, and postoperatively to mitigate the associated risks to optimize outcomes.

The effect of obesity on perioperative morbidity in oblique lumbar interbody fusion

OBJECTIVE

Obese patients have been shown to have longer operative times and more complications from surgery. However, for obese patients undergoing minimally invasive surgery, these differences may not be as significant. In the lateral position, it is thought that obesity is less of an issue because gravity pulls the visceral fat away from the spine; however, this observation is primarily anecdotal and based on expert opinion. The authors performed oblique lumbar interbody fusion (OLIF) and they report on the perioperative morbidity in obese and nonobese patients.

METHODS

The authors conducted a retrospective review of patients who underwent OLIF performed by 3 spine surgeons and 1 vascular surgeon at the University of California, San Francisco, from 2013 to 2018. Data collected included demographic variables; approach-related factors such as operative time, blood loss, and expected temporary approach-related sequelae; and overall complications. Patients were categorized according to their body mass index (BMI). Obesity was defined as a BMI ≥ 30 kg/m2, and severe obesity was defined as a BMI ≥ 35 kg/m2.

RESULTS

There were 238 patients (95 males and 143 females). There were no significant differences between the obese and nonobese groups in terms of sex, levels fused, or smoking status. For the entire cohort, there was no difference in operative time, blood loss, or complications when comparing obese and nonobese patients. However, a subset analysis of the 77 multilevel OLIFs that included L5-S1 demonstrated that the operative times for the nonobese group was 223.55 ± 57.93 minutes, whereas it was 273.75 ± 90.07 minutes for the obese group (p = 0.004). In this subset, the expected approach-related sequela rate was 13.2% for the nonobese group, whereas it was 33.3% for the obese group (p = 0.039). However, the two groups had similar blood loss (p = 0.476) and complication rates (p = 0.876).

CONCLUSIONS

Obesity and morbid obesity generally do not increase the operative time, blood loss, approach-related sequelae, or complications following OLIF. However, obese patients who undergo multilevel OLIF that includes the L5-S1 level do have longer operative times or a higher rate of expected approach-related sequelae. Obesity should not be considered a contraindication to multilevel OLIF, but patients should be informed of potentially increased morbidity if the L5-S1 level is to be included.

Lumbar spinal canal stenosis in patients with diffuse idiopathic skeletal hyperostosis: Surgical outcomes after posterior decompression surgery without spinal instrumentation

BACKGROUND

To evaluate surgical outcomes after posterior decompression surgery for lumbar spinal canal stenosis (LSS) in patients with diffuse idiopathic skeletal hyperostosis (DISH).

METHODS

The patients (n = 184; 132 males and 52 females; mean age 72.0 years; mean follow-up 30.7 months) who underwent posterior decompression surgery for LSS were identified and classified as either DISH (D) or non-DISH (N) based on whole spine radiograph findings. Data on age, gender, American Society of Anesthesiologists (ASA) classification, operation time, and estimated blood loss, were evaluated, while radiographic parameters were measured from radiographs obtained pre- and post-operatively.

RESULTS

Mean age and ASA classification were comparable between the two groups, while the proportion of males was significantly higher in the D group (87.5%) than in the N group (67.6%) (p = 0.016). Further, mean operation time was longer in the D group (89.0 min) than in the N group (73.7 min) (p = 0.036) and mean estimated blood loss was larger in the D group (98.7 g) than in the N group (51.9 g) (p = 0.006). At two years after surgery, the development of anterior translation was significantly higher in the D group (33.3%) than in the N group (17.3%) (p = 0.021). Improvements in ODI and SF-8 after the surgery were better in the N group than in the D group.

CONCLUSIONS

Compared to LSS patients without DISH who also underwent posterior decompression surgery for LSS, surgery in patients with DISH was characterized by greater blood loss, longer operation time, increased translation at the decompressed segment, and poor recovery.

The Impact of Body Mass Index (BMI) on 30-day Outcomes Following Posterior Spinal Fusion in Neuromuscular Scoliosis

STUDY DESIGN

Retrospective.

OBJECTIVE

Assess the impact of varying severity of BMI on 30-day outcomes following posterior spinal fusions in neuromuscular scoliosis.

SUMMARY OF BACKGROUND DATA

Obesity in the pediatric population is shown to be associated with adverse outcomes across varying specialties. The weight-outcome relationship in neuromuscular scoliosis has not been thoroughly investigated.

METHODS

The 2012-2016 American College of Surgeons - National Surgical Quality Improvement (ACS-NSQIP) database was queried using Current Procedural Terminology codes 22800, 22802, and 22804 to identify patients undergoing posterior spinal fusion for neuromuscular scoliosis only. BMI was classified into four groups based on the Center for Disease Control (CDC) BMI-for-age percentile chart - Normal weight (BMI ≥5th to <85th percentile), Underweight (<5th percentile), Overweight (≥85th to <95th percentile) and Obese (≥95th percentile). Multivariate regression models were built to understand the impact of varying BMI severity classes on 30-day outcomes.

RESULTS

A total of 1291 patients underwent posterior spinal fusion for neuromuscular scoliosis. A total of 695 (53.8%) were normal weight, 286 (22.2%) were underweight, 145 (11.2%) were overweight, and 165 (12.8%) were obese. Obese patients versus normal weight patients were at a significantly higher risk of surgical site infections (OR 2.15; P = 0.035), wound dehiscence (OR 1.58; P = 0.037), urinary tract infections (OR 3.41; P = 0.010), and 30-day readmissions (OR 1.94; P = 0.029). Of note, overweight versus normal weight individuals had higher odds of cardiopulmonary complications (OR 8.82; P = 0.024). No significant associations were seen for varying BMI and other 30-day outcomes.

CONCLUSIONS

Obese neuromuscular patients undergoing PSF have higher odds of experiencing adverse outcomes, particularly surgical site infections, urinary tract infections, and readmissions. Providers should promote prevention strategies, such as dietary modification and/or early physical activity in these high-risk patients to minimize the risks of experiencing complications in the acute postoperative period.

LEVEL OF EVIDENCE

3.

Obese Patients Benefit, but do not Fare as Well as Nonobese Patients, Following Lumbar Spondylolisthesis Surgery: An Analysis of the Quality Outcomes Database

BACKGROUND

Given recent differing findings following 2 randomized clinical trials on degenerative lumbar spondylolisthesis (DLS) surgery, there is a need to better define how subsets of patients fare following surgery.

OBJECTIVE

To investigate the impact of obesity on patient-reported outcomes (PROs) following DLS surgery.

METHODS

A total of 12 high-enrolling sites were queried, and we found 797 patients undergoing surgery for grade 1 DLS. For univariate comparisons, patients were stratified by BMI ≥ 30 kg/m2 (obese) and &lt; 30 kg/m2 (nonobese). Baseline, 3-mo, and 12-mo follow-up parameters were collected. PROs included the North American Spine Society satisfaction questionnaire, numeric rating scale (NRS) back pain, NRS leg pain, Oswestry Disability Index (ODI), and EuroQoL-5D (EQ-5D) Questionnaire.

RESULTS

We identified 382 obese (47.9%) and 415 nonobese patients (52.1%). At baseline, obese patients had worse NRS back pain, NRS leg pain, ODI, and EQ-5D scores (P &lt; .001, P = .01, P &lt; .001, and P = .02, respectively). Both cohorts improved significantly for back and leg pain, ODI, and EQ-5D at 12 mo (P &lt; .001). At 12 mo, similar proportions of obese and nonobese patients responded that surgery met their expectations (62.6% vs 67.4%, P = .24). In multivariate analyses, BMI was independently associated with worse NRS leg pain and EQ-5D at 12 mo (P = .01 and P &lt; .01, respectively) despite adjusting for baseline differences.

CONCLUSION

Obesity is associated with inferior leg pain and quality of life—but similar back pain, disability, and satisfaction—12 mo postoperatively. However, obese patients achieve significant improvements in all PRO metrics at 12 mo.

Bariatric surgery before elective posterior lumbar fusion is associated with reduced medical complications and infection

BACKGROUND CONTEXT

Severely obese patients with operative spinal pathology present a challenge to the spine surgeon, given the increased complication risk.

PURPOSE

We aimed to determine the impact of bariatric surgery (BS) on perioperative complications of posterior lumbar fusion.

STUDY DESIGN

This is a retrospective cohort study.

PATIENT SAMPLE

Patients undergoing posterior lumbar fusion surgery in the State Inpatient Databases of New York, Florida, North Carolina, Nebraska, Utah, and California comprised the patient sample.

OUTCOMES

Thirty-day medical complications, surgical complications (nerve injury, infection, revision), death, readmission, and hospital length of stay (LOS) were the study's outcomes.

METHODS

We analyzed 156,517 patients using International Classification of Diseases, Ninth Revision codes. Patients were categorized into three groups: Group 1: history of BS and obesity, Group 2: severe obesity, body mass index (BMI)>40 (severely obese), and Group 3: normal weight, BMI<25 (non-obese). Logistic and linear multivariate regressions were performed to compare complications and LOS, respectively, between BS and severely obese groups and BS and non-obese groups while controlling for confounders. There were no sources of funding for this study.

RESULTS

There were 590 patients with BS, 5,791 severely obese, and 150,136 non-obese. Comparing BS with severely obese, BS had significantly lower rates of respiratory failure (odds ratio [OR] 0.59, p=.019), urinary tract infection (OR 0.64, p=.031), acute renal failure (OR 0.39, p=.007), overall medical complications (OR 0.59, p<.001), and infection (OR 0.65, p=.025). Bariatric surgery also had significantly lower hospital LOS (B=-0.46, p=.01). Comparing BS with non-obese, there were no significant differences in medical complications; however, BS had significantly higher rates of infection (OR 2.70, p<.001), reoperation (OR 2.05, p=.045), and readmission (OR 1.89, p<.001).

CONCLUSION

Bariatric surgery before elective posterior lumbar fusion mitigates risk of medical complications and infection. However, these patients still have increased risk of infection, revision surgery, and readmission compared with patients with normal BMI. Surgeons might consider referral for BS for the severely obese patient before undergoing spine surgery.

Multidisciplinary Evaluation Leads to the Decreased Utilization of Lumbar Spine Fusion: An Observational Cohort Pilot Study

STUDY DESIGN

Observational cohort pilot study.

OBJECTIVE

To determine the impact of a multidisciplinary conference on treatment decisions for lumbar degenerative spine disease.

SUMMARY OF BACKGROUND DATA

Multidisciplinary decision making improves outcomes in many disciplines. The lack of integrated systems for comprehensive care for spinal disorders has contributed to the inappropriate overutilization of spine surgery in the United States.

METHODS

We implemented a multidisciplinary conference involving physiatrists, anesthesiologists, pain specialists, neurosurgeons, orthopaedic spine surgeons, physical therapists, and nursing staff. Over 10 months, we presented patients being considered for spinal fusion or who had a complex history of prior spinal surgery. We compared the decision to proceed with surgery and the proposed surgical approach proposed by outside surgeons with the consensus of our multidisciplinary conference. We also assessed comprehensive demographics and comorbidities for the patients and examined outcomes for surgical patients.

RESULTS

A total of 137 consecutive patients were reviewed at our multidisciplinary conference during the 10-month period. Of these, 100 patients had been recommended for lumbar spine fusion by an outside surgeon. Consensus opinion of the multidisciplinary conference advocated for nonoperative management in 58 patients (58%) who had been previously recommended for spinal fusion at another institution (χ  = 26.6; P < 0.01). Furthermore, the surgical treatment plan was revised as a product of the conference in 28% (16 patients) of the patients who ultimately underwent surgery (χ  = 43.6; P < 0.01). We had zero 30-day complications in surgical patients.

CONCLUSION

Isolated surgical decision making may result in suboptimal treatment recommendations. Multidisciplinary conferences can reduce the utilization of lumbar spinal fusion, possibly resulting in more appropriate use of surgical interventions with better candidate selection while providing patients with more diverse nonoperative treatment options. Although long-term patient outcomes remain to be determined, such multidisciplinary care will likely be essential to improving the quality and value of spine care.

LEVEL OF EVIDENCE

3.

Could the Topping-Off Technique Be the Preventive Strategy against Adjacent Segment Disease after Pedicle Screw-Based Fusion in Lumbar Degenerative Diseases? A Systematic Review

The "topping-off" technique is a new concept applying dynamic or less rigid fixation such as hybrid stabilization device (HSD) or interspinous process device (IPD) for the purpose of avoiding adjacent segment disease (ASD) proximal to the fusion construct. A systematic review of the literature was performed on the effect of topping-off techniques to prevent or decrease the occurrence of ASD after lumbar fusion surgery. We searched through major online databases, PubMed and MEDLINE, using key words related to "topping-off" technique. We reviewed the surgical results of "topping-off" techniques with either HSD or IPD, including the incidence of ASD at two proximal adjacent levels (index and supra-adjacent level) as compared to the fusion alone group. The results showed that the fusion alone group had statistically higher incidence of radiographic (52.6%) and symptomatic (11.6%) ASD at the index level as well as higher incidence (8.1%) of revision surgery. Besides, the HSD (10.5%) and fusion groups (24.7%) had statistically higher incidences of radiographic ASD at supra-adjacent level than the IPD (1%). The findings suggest that the "topping-off" technique may potentially decrease the occurrence of ASD at the proximal motion segments. However, higher quality prospective randomized trials are required prior to wide clinical application.

Associations between Obesity and Spinal Diseases: A Medical Expenditure Panel Study Analysis

Background: The link between body weight status and spinal diseases has been suggested by a number of cross-sectional and cohort studies with a limited range of patient populations. No population-representative samples have been used to examine the link between obesity and spinal diseases. The present study is based on a nationally representative sample drawn from the Medical Expenditure Panel Survey. Methods: Using the cross-sectional sample of the 2014 Medical Expenditure Panel Study, we built four weighted logistic regression analyses of the associations between body weight status and the following four spinal diseases: low back pain, spondylosis, other cervical disorders and intervertebral disc disorder (IDD). Each respondent's body weight status was used as the key independent variable with three categories: normal/underweight, overweight, and obese. We controlled for marital status, gender, age, smoking status, household income, health insurance coverage, educational attainment and the use of health services for other major categories of diseases. Results: A total sample of 23,048 respondents was used in our analysis. Overweight and obese respondents, as compared to normal/underweight respondents, were more likely to develop lower back problems (Overweight: logged odds = 0.218, p < 0.01; Obese: logged odds = 0.395, p < 0.001) and IDD (Overweight: logged odds = 0.441, p < 0.05; Obese: logged odds = 0.528, p < 0.001). The associations between bodyweight status and spondylitis were statistically insignificant (Overweight: logged odds = 0.281, p = 0.442; Obese: logged odds = 0.680, p = 0.104). The associations between body weight status and other cervical disorders (Overweight: logged odds = -0.116, p = 0.304; Obese: logged odds = -0.160, p = 0.865) were statistically insignificant. Conclusions: As the first study using a national sample to study bodyweight and spinal diseases, our paper supports the hypothesis that obesity adds to the burden of low back pain and IDD. Longitudinal and interventional studies are needed to understand the specific mechanisms behind these positive associations.

Impact of obesity on complications and outcomes: a comparison of fusion and nonfusion lumbar spine surgery

OBJECTIVE Prior studies have shown obesity to be associated with higher complication rates but equivalent clinical outcomes following lumbar spine surgery. These findings have been reproducible across lumbar spine surgery in general and for lumbar fusion specifically. Nevertheless, surgeons seem inclined to limit the extent of surgery, perhaps opting for decompression alone rather than decompression plus fusion, in obese patients. The purpose of this study was to ascertain any difference in clinical improvement or complication rates between obese and nonobese patients following decompression alone compared with decompression plus fusion for lumbar spinal stenosis (LSS). METHODS The Quality Outcomes Database (QOD), formerly known as the National Neurosurgery Quality and Outcomes Database (N²QOD), was queried for patients who had undergone decompression plus fusion (D+F group) versus decompression alone (D+0 group) for LSS and were stratified by a body mass index (BMI) ≥ 30 kg/m² (obese) or < 30 kg/m² (nonobese). Demographic, surgical, and health-related quality of life data were compared. RESULTS In the nonobese cohort, 947 patients underwent decompression alone and 319 underwent decompression plus fusion. In the obese cohort, 844 patients had decompression alone and 337 had decompression plus fusion. There were no significant differences in the Oswestry Disability Index score or in leg pain improvement at 12 months when comparing decompression with fusion to decompression without fusion in either obese or nonobese cohorts. However, absolute improvement in back pain was less in the obese group when decompression alone had been performed. Blood loss and operative time were lowest in the nonobese D+0 cohort and were higher in obese patients with or without fusion. Obese patients had a longer hospital stay (4.1 days) than the nonobese patients (3.3 days) when fusion had been performed. In-hospital stay was similar in both obese and nonobese D+0 cohorts. No significant differences were seen in 30-day readmission rates among the 4 cohorts. CONCLUSIONS Consistent with the prior literature, equivalent clinical outcomes were found among obese and non-obese patients treated for LSS. In addition, no difference in clinical outcomes as related to the extent of the surgical procedure was observed between obese and nonobese patients. Within the D+0 group, the nonobese patients had slightly better back pain scores at 2 years postoperatively. There may be a higher blood product requirement in obese patients following spine surgery, as well as an extended hospital stay, when fusion is performed. While obesity may influence the decision for or against surgery, the data suggest that obesity should not necessarily alter the appropriate procedure for well-selected surgical candidates.