The Effects of Obesity on Spine Surgery: A Systematic Review of the Literature

Obesity Does Not Negatively Affect Patient-perceived Outcomes After Cervical Disc Replacement for Disc Herniation

STUDY DESIGN

Retrospective review.

OBJECTIVE

To assess the impact of Body Mass Index (BMI) on patient-reported outcome measures (PROMs) after cervical disc replacement (CDR).

BACKGROUND

BMI may affect PROMs after spine surgery.

METHODS

Primary CDR recipients for herniated disc(s) with BMI <40 were retrospectively selected from a single-surgeon registry. Cohorts were divided into non-obese (BMI <30) and obese (BMI ≥30). Intercohort in-hospital complication rates were compared through independent samples t tests. Pre/postoperative PROMs were compared between cohorts through multivariable regression accounting for demographic differences. Final follow-up dates between patients averaged 11.8 ± 9.3 months. PROMs assessed included Patient-reported Outcomes Measurement Information System-Physical Function, Neck Disability Index, Visual Analog Scale-Neck, Visual Analog Scale-Arm, and the 9-item Patient Health Questionnaire. Improvements in PROMs were evaluated and compared at each follow-up within cohorts through paired t tests. The magnitude of improvement in PROMs from preoperative baseline at 6-week follow-up (∆PROM-6W) and final follow-up (∆PROM-FF) along with achievement rates of minimum clinically important differences were compared between cohorts through multivariable regression accounting for demographic differences.

RESULTS

Of 153 patients, 53 patients were noted as obese. Demographic differences included age, prevalence of hypertension and diabetes, and comorbidity burden scores ( P ≤ 0.011, all). No significant variations in in-hospital complications were found. The non-obese cohort demonstrated improvements in all PROMs at 6 weeks and final follow-up periods ( P ≤ 0.005, all). The obese cohort demonstrated improvements in all postoperative PROMs besides 9-item Patient Health Questionnaire at 6 weeks ( P ≤ 0.015, all). After accounting for age and comorbidity variations, there were no significant intercohort differences in raw PROM scores, ∆PROM-6W, ∆PROM-FF, or minimum clinically important difference achievement rates.

CONCLUSIONS

Regardless of BMI, patients experience significant improvements in physical function, disability, pain, and mental health after CDR for disc herniation. Patients with obesity do not suffer inferior patient-perceived outcomes after CDR. These findings may help surgeons counsel patients in the preoperative period.

Associations of overweight/obesity with patient-reported outcome measures after oblique lumbar interbody fusion

Background

Oblique lateral interbody fusion (OLIF) combined with transpedicular screw fixation has been practiced for degenerative spinal diseases of elderly patients for years. However, overweight patients have been shown to have longer operative times and more complications from surgery. The effect on clinical outcome is still uncertified. The objective of this study was to determine is overweight a risk factor to clinical outcome of OLIF combined with transpedicular screw fixation technique.

Material and methods

A retrospective study in patients submitted to OLIF combined with transpedicular screw fixation from January 2018 to August 2019 was conducted. VAS score, ODI score and EQ5D were measured before the operation and one year after the operation.

Results

A total of 111 patients were included with 48 patients in the non-obese group and 55 patients in the overweight/obese group. There was no significant difference between the two groups in gender, age, smoking history, hypertension, chronic kidney disease and diabetes mellitus. Overweight/obese group has higher BMI (28.4 vs. 22.7, p < 0.001) than non-obese group. There was no difference between the two groups in pre-operative VAS score, ODI score and EQ5D score. However, the healthy weight group improved much more than the overweight score in VAS score, ODI score and EQ5D score.

Conclusion

The overweight/obese patient group had clinical outcomes worse than the non-obese group in terms of pain relief and life functions.

Does obesity and varying body mass index affect the clinical outcomes and safety of biportal endoscopic lumbar decompression? A comparative cohort study

BACKGROUND

Endoscopic spine surgery has recently grown in popularity due to the potential benefits of reduced pain and faster recovery time as compared to open surgery. Biportal spinal endoscopy has been successfully applied to lumbar disc herniations and lumbar spinal stenosis. Obesity is associated with increased risk of complications in spine surgery. Few prior studies have investigated the impact of obesity and associated medical comorbidities with biportal spinal endoscopy.

METHODS

This study was a prospectively collected, retrospectively analyzed comparative cohort design. Patients were divided into cohorts of normal body weight (Bone Mass Index (BMI)18.0-24.9), overweight (BMI 25.0-29.9) and obese (BMI > 30.0) as defined by the World Health Organization (WHO). Patients underwent biportal spinal endoscopy by a single surgeon at a single institution for treatment of lumbar disc herniations and lumbar spinal stenosis. Demographic data, surgical complications, and patient-reported outcomes were analyzed. Statistics were calculated amongst treatment groups using analysis of variance and chi square where appropriate. Statistical significance was determined as p < 0.05.

RESULTS

Eighty-four patients were followed. 26 (30.1%) were normal BMI, 35 (41.7%) were overweight and 23 (27.4%) were obese. Patients with increasing BMI had correspondingly greater American Society of Anesthesiologist (ASA) scores. There were no significant differences in VAS Back, VAS Leg, and ODI scores, or postoperative complications among the cohorts. There were no cases of surgical site infections in the cohort. All cohorts demonstrated significant improvement up to 1 year postoperatively.

CONCLUSIONS

This study demonstrates that obesity is not a risk factor for increased perioperative complications with biportal spinal endoscopy and has similar clinical outcomes and safety profile as compared to patients with normal BMI. Biportal spinal endoscopy is a promising alternative to traditional techniques to treat common lumbar pathology.

A Comparative Study of Wound Infections Following Wound Closure Using Staples and Absorbable Sutures Among Obese Patients Undergoing Lumbar Fusion Surgery

Background Infections of the wounds, organs, or spaces that develop following surgery are known as surgical site infections (SSIs). The incidence of wound infections in obese patients undergoing lumbar spine surgery with the use of absorbable sutures versus staples for skin closure has not been studied previously. Materials and methods We conducted a retrospective observational study in our hospital where cases of lumbar spine surgery meeting the inclusion criteria were chosen retrospectively from March 2021 to March 2023. A total of 40 patients aged >18 years and <75 years who underwent lumbar spine surgery were covered by this investigation. Two cohorts with 20 patients in each were chosen from the population. Group A used a skin stapler to close wounds, whereas group B used absorbable sutures. The number of wound infections was the main result. Using SPSS version 23.0 (IBM SPSS Statistics, Armonk, NY), all data were analyzed after being entered into an Excel sheet (Microsoft Corp., Redmond, WA). Results A total of 40 participants were included in this study, and it revealed that there was no discernible variation in the groups' mean age or gender distribution. There is a significantly higher incidence of SSI in the absorbable suture group (35%) compared to the staple group (15%). The mean duration in days for the development of SSI in the absorbable suture group (9.86±2.12) was early compared to the staple group (12.67±2.08), which was statistically significant (p<0.05). Conclusion Compared to absorbable sutures, the current study showed a decreased incidence of surgical site infection in obese individuals receiving skin staples for wound closure.

Impact of Obesity on Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgeries: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the impact of obesity on various outcomes in patients undergoing minimally invasive transforaminal lumbar interbody fusion (TLIF) surgeries.

METHODS

PubMed, Scopus, Embase, and Cochrane Library databases were screened for studies reporting outcomes in obese and nonobese patients undergoing TLIF surgeries. Studies reporting operative time, estimated blood loss, length of hospital stay, incidence of pseudoarthrosis, Oswestry Disability Index (ODI) scores, pain scores (Visual Analog Scale, VAS), and PROMIS PF scores were included. A qualitative and quantitative analysis was performed to calculate mean differences or odds ratios (ORs) using random-effects models.

RESULTS

Fourteen good-quality studies were included in this review, with a combined sample size of 4,889 participants. The analysis revealed that patients with obesity had slightly longer operative times compared to patients with normal weight, with a mean difference of 14.87 minutes, though not significant. Similarly, morbidly obese patients had a mean difference of 21.44 minutes in operative time. Estimated blood loss was comparable in both groups. However, morbidly obese patients had longer hospital stays, with a mean difference of 8.18 days and obese patients have 20% higher odds of experiencing complications compared to nonobese patients. The incidence of pseudoarthrosis, ODI scores, or pain scores (VAS back and leg) were similar in obese and normal weight patients.

CONCLUSIONS

Obesity, particularly morbid obesity, may have an impact on certain outcomes in patients undergoing minimally invasive TLIF surgeries. Morbidly obese patients tend to have significantly longer operative times with significantly longer hospital stays than nonobese patients.

Racial Differences in Perioperative Complications, Readmissions, and Mortalities After Elective Spine Surgery in the United States: A Systematic Review Using AI-Assisted Bibliometric Analysis

STUDY DESIGN

Systematic Review and Meta-analysis.

OBJECTIVES

To evaluate the impact of race on post-operative outcomes and complications following elective spine surgery in the United States.

METHODS

PUBMED, MEDLINE(R), ERIC, EMBASE, and SCOPUS were searched for studies documenting peri-operative events for White and African American (AA) patients following elective spine surgery. Pooled odds ratios were calculated for each 90-day outcome and meta-analyses were performed for 4 peri-operative events and 7 complication categories. Sub-analyses were performed for each outcome on single institution (SI) studies and works that included <100,000 patients.

RESULTS

53 studies (5,589,069 patients, 9.8% AA) were included. Eleven included >100,000 patients. AA patients had increased rates of 90-day readmission (OR 1.33, P = .0001), non-routine discharge (OR 1.71, P = .0001), and mortality (OR 1.66, P = .0003), but not re-operation (OR 1.16, P = .1354). AA patients were more likely to have wound-related complications (OR 1.47, P = .0001) or medical complications (OR 1.35, P = .0006), specifically cardiovascular (OR 1.33, P = .0126), deep vein thrombosis/pulmonary embolism (DVT/PE) (OR 2.22, P = .0188) and genitourinary events (OR 1.17, P = .0343). SI studies could only detect racial differences in re-admissions and non-routine discharges. Studies with <100,000 patients replicated the above findings but found no differences in cardiovascular complications. Disparities in mortality were only detected when all studies were included.

CONCLUSIONS

AA patients faced a greater risk of morbidity across several distinct categories of peri-operative events. SI studies can be underpowered to detect more granular complication types (genitourinary, DVT/PE). Rare events, such as mortality, require larger sample sizes to identify significant racial disparities.

Incidence of subsequent surgical decompression following minimally invasive approaches to treat lumbar spinal stenosis: A retrospective review

BACKGROUND CONTEXT

Surgical decompression is the definitive treatment for managing symptomatic lumbar spinal stenosis; however, select patients are poor surgical candidates. Consequently, minimally invasive procedures have gained popularity, but there exists the potential for failure of therapy necessitating eventual surgical decompression.

PURPOSE

To evaluate the incidence and characteristics of patients who require surgical decompression following minimally invasive procedures to treat lumbar spinal stenosis.

STUDY DESIGN/SETTING

Retrospective review.

PATIENT SAMPLE

Patients who underwent minimally invasive procedures for lumbar spinal stenosis (Percutaneous Image-guided Lumbar Decompression [PILD] or interspinous spacer device [ISD]) and progressed to subsequent surgical decompression within 5 years.

OUTCOME MEASURES

The primary outcome was the rate of surgical decompression within 5 years following the minimally invasive approach. Secondary outcomes included demographic and comorbid factors associated with increased odds of requiring subsequent surgery.

METHODS

Patient data were collected using the PearlDiver-Mariner database. The rate of subsequent decompression was described as a percentage while univariable and multivariable regression analysis was used for the analysis of predictors.

RESULTS

A total of 5278 patients were included, of which 3222 (61.04%) underwent PILD, 1959 (37.12%) underwent ISD placement, and 97 (1.84%) had claims for both procedures. Overall, the incidence of subsequent surgical decompression within 5 years was 6.56% (346 of 5278 patients). Variables associated with a significantly greater odds ratio (OR) [95% confidence interval (CI)] of requiring subsequent surgical decompression included male gender and a prior history of surgical decompression by 1.42 ([1.14, 1.77], p = 0.002) and 2.10 times ([1.39, 3.17], p < 0.001), respectively. In contrast, age 65 years and above, a diagnosis of obesity, and a Charlson Comorbidity Index score of three or greater were associated with a significantly reduced OR [95% CI] by 0.64 ([0.50, 0.81], p < 0.001), 0.62 ([0.48, 0.81], p < 0.001), and 0.71 times ([0.56, 0.91], p = 0.007), respectively.

CONCLUSIONS

Minimally invasive procedures may provide an additional option to treat symptomatic lumbar spinal stenosis in patients who are poor surgical candidates or who do not desire open decompression; however, there still exists a subset of patients who will require subsequent surgical decompression. Factors such as gender and prior surgical decompression increase the likelihood of subsequent surgery, while older age, obesity, and a higher Charlson Comorbidity Index score reduce it. These findings aid in selecting suitable surgical candidates for better outcomes in the elderly population with lumbar spinal stenosis.

Impact of obesity on adult spinal deformity (ASD) long-segment spinal fusion radiographic and clinical outcomes

STUDY DESIGN

Retrospective chart review of patients receiving long-segment fusion during a five-year period.

OBJECTIVE

To determine whether obese patients receive comparable benefits when receiving long-segment fusion compared to non-obese patients and to identify factors that may predict hardware failure and post-surgical complications among obese patients.

METHODS

Demographic, spinopelvic radiographic, patient-reported outcome measures (PROMs), and complications data was retrospectively collected from 120 patients who underwent long-segment fusion during a five-year period at one tertiary care medical center. Radiographic measurements were pelvic incidence, pelvic tilt (PT), lumbar lordosis, L4-S1 lordosis, thoracic kyphosis, sagittal vertical axis, PI-LL mismatch, and proximal junction cobb angle at upper instrumented vertebrae + 2 (UIV+2). PROMs were Oswestry disability index, numeric rating scale (NRS) Back Pain, NRS Leg Pain, RAND SF-36 pain, and RAND SF-36 physical functioning. Included patients were adults and had at least 2-years of postoperative follow-up. Descriptive and multivariate statistical analysis was performed with α = 0.05.

RESULTS

Patients with a BMI ≥ 30 (n=63) and patients with a BMI < 30 (n=57) demonstrated comparable improvements (P>0.05) for all spinopelvic radiographic measurements and PROMs. Each cohort demonstrated significant improvements from pre-assessment to post-assessment on nearly all spinopelvic radiographic measurements and PROMs (P<0.05), except PT and L4-S1 lordosis where neither group improved (p=0.95 and 0.58 for PT and P=0.23 and 0.11 for L4-S1 lordosis fornon-obese and obese cohorts respectively) and SF-36 physical functioning where the non-obese cohort not statistically improve (P=0.08). Patients with a BMI ≥ 30 demonstrated an increased incidence of cardiovascular complications (P=0.0293), acute kidney injury (P=0.0241), rod fractures (P=0.0293), and reoperations (P=0.0241) when compared to patients with a BMI < 30.

CONCLUSION

This study adds to a growing body of evidence linking demographic factors with risks of hardware failure. Further, this data challenges the assumption that obese patients may not receive sufficient benefit to be long-segment surgical candidates. However, given their elevated risk for post-operative and delayed hardware complications, obese patients should be appropriately counseling before undergoing surgery.

The significance of metabolic disease in degenerative cervical myelopathy: a systematic review

Introduction

Degenerative cervical myelopathy (DCM) is a form of chronic spinal cord injury, with a natural history of potential for progression over time. Whilst driven by mechanical stress on the spinal cord from degenerative and congenital pathology, the neurological phenotype of DCM is likely to be modified by multiple systemic factors. The role of metabolic factors is therefore of interest, particularly given that ischaemia is considered a key pathological mechanism of spinal cord injury. The objective was therefore to synthesise current evidence on the effect of metabolism on DCM susceptibility, severity, and surgical outcomes.

Methods

A systematic review in MEDLINE and Embase was conducted following PRISMA guidelines. Full-text papers in English, with a focus on DCM and metabolism, including diabetes, cardiovascular disease, anaemia, and lipid profile, were eligible for inclusion. Risk of methodological bias was assessed using the Joanna Briggs Institute (JBI) critical assessment tools. Quality assessments were performed using the GRADE assessment tool. Patient demographics, metabolic factors and the relationships between metabolism and spinal cord disease, spinal column disease and post-operative outcomes were assessed.

Results

In total, 8,523 papers were identified, of which 57 met criteria for inclusion in the final analysis. A total of 91% (52/57) of included papers assessed the effects of diabetes in relation to DCM, of which 85% (44/52) reported an association with poor surgical outcomes; 42% of papers (24/57) discussed the association between cardiovascular health and DCM, of which 88% (21/24) reported a significant association. Overall, DCM patients with diabetes or cardiovascular disease experienced greater perioperative morbidity and poorer neurological recovery. They were also more likely to have comorbidities such as obesity and hyperlipidaemia.

Conclusion

Metabolic factors appear to be associated with surgical outcomes in DCM. However, evidence for a more specific role in DCM susceptibility and severity is uncertain. The pathophysiology and natural history of DCM are critical research priorities; the role of metabolism is therefore a key area for future research focus.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021268814.

Low Body Mass Index Patients Undergoing an Anterior Lumbar Fusion May Have an Increased Risk of Perioperative Complications

BACKGROUND

Previous research has shown that underweight patients may be at a greater risk of experiencing postsurgical complications. The purpose of this study was to investigate the association between body mass index (BMI) and postoperative complications following single-level anterior lumbar fusion (ALF).

METHODS

All single-level elective ALF procedures performed between 2010 and 2020 were identified in the PearlDiver Mariner Database. Patients were separated into 6 groups based on the World Health Organization BMI classifications. Differences in postsurgical complications (ie, deep vein thrombosis, pulmonary embolism, surgical site infection, hardware malfunction, wound dehiscence, and blood transfusion) among BMI categories were assessed using a χ2 contingency test.

RESULTS

Results indicated that underweight patients (BMI <20) were at a significantly greater risk of developing deep vein thromboses, experiencing hardware malfunction, and requiring blood transfusion compared with any other BMI classification (P < 0.001). Results also demonstrated that underweight individuals had similar risks of developing surgical site infection and wound dehiscence compared with patients classified as having obesity class III.

CONCLUSION

Underweight patients may be at a greater risk than currently believed of experiencing postoperative complications following single-level ALF procedures.

CLINICAL RELEVANCE

Patients with a BMI of 20 or less should be carefully evaluated prior to surgical intervention to ensure they are optimized for surgery.

LEVEL OF EVIDENCE: 3

Severe Obesity Is an Independent Risk Factor of Early Readmission and Nonhome Discharge After Cervical Disc Replacement

OBJECTIVE

Despite growing interest in cervical disc replacement (CDR) for conditions such as cervical radiculopathy, limited data exists describing the impact of obesity on early postoperative outcomes and complications. These data are especially important as nearly half of the adult population in the United States is expected to become obese (body mass index [BMI] ≥ 30 kg/m2) by 2030. The goal of this study was to compare the demographics, perioperative variables, and complication rates following CDR.

METHODS

The 2005-2020 American College of Surgeons National Surgical Quality Improvement Program datasets were queried for patients who underwent primary 1- or 2-level CDR. Patients were divided into 3 cohorts: Nonobese (BMI: 18.5-29.9 kg/m2), Obese class-I (BMI: 30-34.9 kg/m2), Obese class-II/III (BMI ≥ 35 kg/m2). Morbidity was defined as the presence of any complication within 30 days postoperatively. Rates of 30-day readmission, reoperation, morbidity, individual complications, length of stay, frequency of nonhome discharge disposition were collected.

RESULTS

A total of 5,397 patients were included for analysis: 3,130 were nonobese, 1,348 were obese class I, and 919 were obese class II/III. There were more 2-level CDRs performed in the class II/III cohort compared to the nonobese group (25.7% vs. 21.5%, respectively; p < 0.05). Class-II/III had more nonhome discharges than class I and nonobese (2.1% vs. 0.5% vs. 0.7%, respectively; p < 0.001). Readmission rates differed as well (nonobese: 0.5%, class I: 1.1%, class II/III: 2.1%; p < 0.001) with pairwise significance between class II/II and nonobese. Class II/III obesity was an independent risk factor for both readmission (odds ratio [OR], 3.32; p = 0.002) and nonhome discharge (OR, 2.51; p = 0.02). Neither 30-day reoperation nor morbidity rates demonstrated significance. No mortalities were reported.

CONCLUSION

Although obese class-II/III were risk factors for 30-day readmission and nonhome discharge, there was no significant difference in reoperation rates or morbidity. CDR procedures can continue to be safely preformed independent of obesity status.

Bariatric Surgery Before Spine Surgery is Associated With Fewer Postsurgical Complications: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To perform a systematic review and meta-analysis investigating the rate of adverse events after spine surgery in patients who underwent bariatric surgery (BS).

SUMMARY OF BACKGROUND DATA

Obesity is an established risk factor for postoperative complications after spine surgery. BS has been associated with improvements in health in patients with severe obesity. However, it is not known whether undergoing BS before spine surgery is associated with reduced adverse outcomes.

MATERIALS AND METHODS

PubMed, EMBASE, Scopus, and Web-of-Science were systematically searched according to "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. The search included indexed terms and text words from database inception to the date of the search (May 27, 2022). Data and estimates were pooled using the Mantel-Haenszel method for random-effects meta-analysis. Risk of bias was assessed using the Joanna Briggs Institute risk of bias tool. The primary outcome was an all-cause complication rate after surgery. Relative risks for surgical and medical complications were assessed.

RESULTS

A total of 4 studies comprising 177,273 patients were included. The pooled analysis demonstrated that the all-cause medical complication rate after spine surgery was lower in patients undergoing BS (relative risk: 0.54, 95% CI: 0.39, 0.74, P < 0.01). There was no difference in rates of surgical complications and 30-day hospital readmission rates between the cohort undergoing BS before spine surgery and the cohort that did not.

CONCLUSION

These analyses suggest that obese patients undergoing BS before spine surgery have significantly lower adverse event rates. Future prospective studies are needed to corroborate these findings.

LEVEL OF EVIDENCE

4.

Impact of body mass index on PROMIS outcomes following lumbar decompression

BACKGROUND

No studies have examined the impact of body mass index (BMI) on newer Patient-Reported Outcomes Measurement Information System (PROMIS) outcomes in patients undergoing lumbar decompression (LD).

METHODS

Patients undergoing LD with preoperative PROMIS measures were stratified into four cohorts: normal (18.5 ≤ BMI < 25 kg/m2), overweight (25 ≤ BMI < 30 kg/m2), obese I (30 ≤ BMI < 35 kg/m2), and obese II-III (BMI ≥ 35 kg/m2). Demographics, perioperative characteristics, and patient-reported outcomes (PROs) were obtained. PROs of PROMIS Physical Function (PROMIS-PF), PROMIS Anxiety (PROMIS-A), PROMIS Pain Interference (PROMIS-PI), PROMIS Sleep Disturbance (PROMIS-SD), Patient Health Questionnaire-9 (PHQ-9), Visual Analog Scale (VAS) Back Pain (VAS-BP), VAS Leg Pain (VAS-LP), and Oswestry Disability Index (ODI) were collected at preoperative and up to 2-year postoperative time points. Minimum clinically important difference (MCID) achievement was determined through comparison of previously established values. Comparison between cohorts were determined through inferential statistics.

RESULTS

A total of 473 patients were identified, with stratification of 125 patients in the normal cohort, 161 in the overweight cohort, 101 in the obese I cohort, and 87 in the obese II-III cohort. Mean postoperative follow-up time was 13.51 ± 8.72 months. Higher BMI patients had higher operative times, longer postoperative length of stay, and greater narcotic consumption (p ≤ 0.001, all). Patients with higher BMI (obese I, obese II-III) reported inferior preoperative PROMIS-PF, VAS-BP, and ODI scores (p ≤ 0.003, all). Postoperatively, obese I-III cohorts demonstrated inferior PROMIS-PF, PHQ-9, VAS-BP, and ODI scores at final follow-up (p ≤ 0.016, all). However, patients demonstrated similar postoperative changes and MCID achievement regardless of preoperative BMI.

CONCLUSION

Patients undergoing lumbar decompression demonstrated similar postoperative improvement in physical function, anxiety, pain interference, sleep disturbance, mental health, pain, and disability outcomes independent of preoperative BMI. However, obese patients reported worse physical function, mental health, back pain, and disability outcomes at final postoperative follow-up. Patients with greater BMI undergoing lumbar decompression demonstrate inferior postoperative clinical outcomes.

Impact of body mass index on outcomes after lumbar spine surgery

The impact of body mass index (BMI) on outcomes after lumbar spine surgery is currently unknown. Previous studies have reported conflicting evidence for patients with high BMI, while little research has been conducted on outcomes for underweight patients. This study aims to examine the impact of BMI on outcomes after lumbar spine surgery. This prospective cohort study enrolled 5622 patients; of which, 194, 5027, and 401 were in the low (< 18.5 kg/m²), normal (18.5-30), and high (≥ 30) BMI groups, respectively. Pain was assessed via the numerical pain rating scale (NPRS) for the lower back, buttock, leg, and plantar area. Quality of life was assessed via the EuroQol 5 Dimension (EQ-5D) and Oswestry Disability Index (ODI). Inverse probability weighting with propensity scores was used to adjust patient demographics and clinical characteristics between the groups. After adjustment, the 1-year postoperative scores differed significantly between groups in terms of leg pain. The proportion of patients who achieved a 50% decrease in postoperative NPRS score for leg pain was also significantly different. Obese patients reported less improvement in leg pain after lumbar spine surgery. The outcomes of patients with low BMI were not inferior to those of patients with normal BMI.

Body Mass Index and Risk of Complications After Posterior Lumbar Spine Fusion: A Matched Cohort Analysis Investigating Underweight and Obese Patients

OBJECTIVE

Previous studies have demonstrated that obesity is associated with increased complications after lumbar fusion. However, there are little published data on the effect of being underweight on lumbar fusion outcomes. The purpose of this study was to elucidate the effect of being underweight versus obese on outcomes after lumbar spinal fusion.

METHODS

Lumbar spinal fusion patients were identified through the PearlDiver Mariner database between 2010 and 2020. Study groups were created using International Classification of Diseases codes to identify preoperative body mass index (BMI) category as morbid obesity (BMI > 40), obesity (BMI 30 to 40), normal BMI (BMI 20 to 30), and underweight (BMI < 20) cohorts. Complications that occurred within 1 year postoperatively in this study and matched control groups were then isolated. Statistical analyses were conducted using the Pearson chi square method.

RESULTS

A total of 62,616 patients were identified in this analysis. This included 1,258 underweight patients (4.0%), 17,996 obese patients (57.5%), and 12,054 morbidly obese patients (38.5%). The number of patients to experience any postoperative complication was 766 (60.9%), 9,440 (52.4%), and 6,982 (57.9%) for the underweight, obese, and morbidly obese cohorts, respectively. Underweight patients showed an increased likelihood of complications related to instrumentation (odds ratio [OR] 1.85, P = 0.0237), revision fusion (OR 1.34, P = 0.04061), pulmonary complications (OR 1.43, P < 0.001), and sepsis (OR 1.91, P < 0.001). Obese patients with BMI 30 to 40 showed increased odds of the following complications: hemorrhages and hematomas (OR 1.20, P = 0.02634), surgical site complications (OR 1.27, P < 0.001), thromboembolism (OR 1.78, P < 0.001), and urinary complications (OR 1.08, P < 0.001). Morbidly obese patients with BMI > 40 showed increased odds of all complications analyzed in this study.

CONCLUSION

This investigation indicates that both underweight and obese patients are at elevated risk of complications after lumbar fusion. Similar to obese patients, underweight patients may benefit from preoperative optimization by nutrition counseling to avoid potential complications.

LEVEL OF EVIDENCE

III.

Risk Factors for 30-day Unplanned Readmission following Surgery for Lumbar Degenerative Diseases: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Surgical procedures for lumbar degenerative diseases (LDD), which have emerged in the 21-century, are commonly practiced worldwide. Regarding financial burdens and health costs, readmissions within 30days following surgery are inconvenient. We performed a systematic review to integrate real-world evidence and report the current risk factors associated with 30-day readmission following surgery for LDD.

METHODS

The Cochrane Library, Embase, and Medline electronic databases were searched from inception to April 2022 to identify relevant studies reporting risk factors for 30-day readmission following surgery for LDD.

RESULTS

Thirty-six studies were included in the review. Potential risk factors were identified in the included studies that reported multivariate analysis results, including age, race, obesity, higher American Society of Anesthesiologists score, anemia, bleeding disorder, chronic pulmonary disease, heart failure, dependent status, depression, diabetes, frailty, malnutrition, chronic steroid use, surgeries with anterior approach, multilevel spinal surgeries, perioperative transfusion, presence of postoperative complications, prolonged operative time, and prolonged length of stay.

CONCLUSIONS

There are several potential perioperative risk factors associated with unplanned readmission following surgery for LDD. Preoperatively identifying patients that are at increased risk of readmission is critical for achieving the best possible outcomes.

Recommendations for enhanced post-surgical recovery in the spine (REPOC)

INTRODUCTION/OBJECTIVES

Enhanced recovery after surgery (ERAS) constitutes a multimodal approach, based on available scientific evidence, that achieves better patient's functionality, reduces pain, and even lowers financial costs. The present consensus statement proposes the standards for the implementation of ERAS programs to lumbar fusion surgery, a meant benchmark we call REPOC.

METHODOLOGY

A multidisciplinary group of experts was set up ad hoc to review consensus recommendations for lumbar arthrodesis, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

As a result, 23 recommendations were selected throughout the preoperative, intraoperative, and postoperative phases of the surgical procedure. A 29-item checklist was also drawn up to implement REPOC protocols in spinal surgeries.

CONCLUSIONS

This list of recommendations will facilitate the implementation of this multimodal approach as a safe and effective tool for reducing adverse events in our environment.

[Translated article] Recommendations for enhanced post-surgical recovery in the spine (REPOC)

INTRODUCTION/OBJECTIVES

Enhanced recovery after surgery (ERAS) constitutes a multimodal approach, based on available scientific evidence, that achieves better patient's functionality, reduces pain, and even lowers financial costs. The present consensus statement proposes the standards for the implementation of ERAS programmes to lumbar fusion surgery, a meant benchmark we call REPOC.

METHODOLOGY

A multidisciplinary group of experts was set up ad hoc to review consensus recommendations for lumbar arthrodesis, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

As a result, 23 recommendations were selected throughout the preoperative, intraoperative, and postoperative phases of the surgical procedure. A 29-item checklist was also drawn up to implement REPOC protocols in spinal surgeries.

CONCLUSIONS

This list of recommendations will facilitate the implementation of this multimodal approach as a safe and effective tool for reducing adverse events in our environment.

Overweight increases perioperative spinal surgery complications: a single-center retrospective study

BACKGROUND

The World Health Organization (WHO) defines a person with a body mass index (BMI) greater than or equal to 25 kg/m² as overweight. Being overweight is a lifestyle-related disease; however, little is known about the impact of overweight on the perioperative complications of orthopedic surgery. This study aimed to define the effect of overweight on the perioperative complications of spinal surgery.

METHODS

This retrospective case series study reviewed 269 consecutive patients who underwent spinal surgery. These patients were divided into the overweight (OW) and non-overweight (NOW) groups. Age, BMI, surgical time, blood loss, and perioperative complications were evaluated and compared between the groups.

RESULTS

There were 117 patients (43%) in the OW group and 152 (57%) in the NOW group. Cervical surgery was performed in 72 cases, thoracic surgery in 34, and lumbosacral surgery in 159. The surgical time was significantly longer in the OW group than in the NOW group (204.6 ± 98 min vs. 175 ± 75 min; p = 0.01). Blood loss was greater in the OW group than in the NOW group (446.8 ± 447.9 mL vs. 279 ± 296.5 mL; p = 0.00). Durotomy was more frequent in the OW group than in the NOW group (10 vs. 3 cases; p = 0.02). There was no difference in complications other than durotomy.

CONCLUSIONS

OW patients had longer surgical time, more blood loss, and more frequent durotomy than NOW patients. These findings indicate that overweight increases perioperative complications of spinal surgery.

An Ensemble Learning Approach to Improving Prediction of Case Duration for Spine Surgery: Algorithm Development and Validation

BACKGROUND

Estimating surgical case duration accurately is an important operating room efficiency metric. Current predictive techniques in spine surgery include less sophisticated approaches such as classical multivariable statistical models. Machine learning approaches have been used to predict outcomes such as length of stay and time returning to normal work, but have not been focused on case duration.

OBJECTIVE

The primary objective of this 4-year, single-academic-center, retrospective study was to use an ensemble learning approach that may improve the accuracy of scheduled case duration for spine surgery. The primary outcome measure was case duration.

METHODS

We compared machine learning models using surgical and patient features to our institutional method, which used historic averages and surgeon adjustments as needed. We implemented multivariable linear regression, random forest, bagging, and XGBoost (Extreme Gradient Boosting) and calculated the average R², root-mean-square error (RMSE), explained variance, and mean absolute error (MAE) using k-fold cross-validation. We then used the SHAP (Shapley Additive Explanations) explainer model to determine feature importance.

RESULTS

A total of 3189 patients who underwent spine surgery were included. The institution's current method of predicting case times has a very poor coefficient of determination with actual times (R²=0.213). On k-fold cross-validation, the linear regression model had an explained variance score of 0.345, an R² of 0.34, an RMSE of 162.84 minutes, and an MAE of 127.22 minutes. Among all models, the XGBoost regressor performed the best with an explained variance score of 0.778, an R² of 0.770, an RMSE of 92.95 minutes, and an MAE of 44.31 minutes. Based on SHAP analysis of the XGBoost regression, body mass index, spinal fusions, surgical procedure, and number of spine levels involved were the features with the most impact on the model.

CONCLUSIONS

Using ensemble learning-based predictive models, specifically XGBoost regression, can improve the accuracy of the estimation of spine surgery times.

Nutritional Optimization for Post-Spinal Surgery Recovery

Adequate nutritional intake is a key component of uncomplicated recovery from spinal surgery. Though much in the literature exists regarding its importance, specific dietary regimens for spinal surgery remain understudied, and little is available in compiling both preoperative and postoperative nutritional recommendations for patients. The complexity that may exist with these recommendations -- especially in the context of patients with diabetes or those who use substances -- has led in recent years to the development of protocols such as Enhanced Recovery After Surgery (ERAS), which gives providers a guideline upon which to base their nutritional counselling. More innovative regimens, such as the use of bioelectrical impedance analyses to assess nutritional status, have also emerged, resulting in a vast array of dietary recommendations and protocols for spinal surgery. In the following paper, we aim to compile a few of these guidelines, comparing various preoperative and postoperative nutritional strategies as well as making note of special considerations, like patients with diabetes or those who use substances. We also work to overview several such dietary "protocols" available in the literature, with a special focus on ERAS and more recent regimens like the Northwestern High-Risk Spine Protocol. We briefly mentioned preclinical work on novel nutritional recommendations as well. Ultimately, we hope to highlight the importance of nutrition in spinal surgery and address the need for greater cohesion of dietary strategies already in existence.

Factors associated with hardware failure after lateral thoracolumbar fusions - A ten year case series

OBJECTIVE

Thoracolumbar lateral interbody fusions (tLLIF) are one tool in the spine surgeon's toolbox to indirectly decompress neuroforamina while also improving segmental lordosis in a biomechanically distinct manner from posterior fusions. When part of a concomitant posterior construct, hardware failure (HF), sometimes requiring revision surgery, can occur. We sought to study the relationship between tLLIF and HF.

METHODS

We conducted a retrospective study on consecutive patents who underwent tLLIF at a single academic center between January 2012 and December 2021 by seven unique neurosurgeons. Patients were excluded if they had no posterior instrumentation within their construct or if they had less than six months of follow-up. Hardware failure was defined as screw breakage or rod fracture seen on postoperative imaging.

RESULTS

232 patients were identified; 6 (2.6 %) developed HF throughout a mean follow-up of 1182 days (range =748-1647 days). Adjacent segment disease was the most common pathology addressed (75 patients (32.3 %)). The amount of posterior instrumentation both in the surgery in question and in the total construct were significantly higher in the HF cohort (4.33 ± 1.52 levels, 5.83 ± 3.36 levels) versus the non-HF cohort (2.08 ± 0.296 levels, p = 0.014; 2.86 ± 0.316 levels, p = 0.003, respectively). The number of interbody devices added in the index surgery and in the entire construct were both significantly higher in the HF cohort (3.33 ± 0.666 interbody devices, 3.33 ± 0.666 devices) than in the non-HF cohort (1.88 ± 0.152 interbody devices, p = 0.002; 2.31 ± 0.158 devices, p = 0.036, respectively). Higher amounts of lateral levels of fusion approached significance for association with HF (HF: 2.67 ± 0.844 levels, no HF: 1.73 ± 1.26 levels, p = 0.076). On multivariate analysis, only the number of interbody devices added in the index surgery was predictive of HF (Odds ratio=2.3, 95 % confidence interval=1.25-4.23, p = 0.007).

CONCLUSION

Greater levels of posterior fusion, and greater numbers of interbody devices in an index surgery and in a construct as a whole, were associated with higher rates of HF in our cohort of patients with tLLIF. Greater numbers of lateral segments fused in this population may also be related to HF.

Prognostic Factors Impacting Surgical Outcomes in Patients With Cervical Spondylotic Myelopathy

The purpose of surgical decompression in patients who have CSM is to stop the progression of symptoms and hopefully improve function. It is critical to understand prognostic factors that affect the outcome. Factors intrinsic to the patient that can adversely affect outcomes include diabetes, older age, tobacco use, the presence of mental health disease, and obesity. MRI imaging findings of T2 hyperintensity and clinical duration and severity of symptoms is also associated with poorer outcomes. Patients should be counseled regarding the efficacy of decompressive procedures for CSM and given realistic expectations based on their unique biophysical profiles.

A comparison study on patient-reported outcome between obese and non-obese patients with central lumbar spinal stenosis undergoing surgical decompression: 14,984 patients in the National Swedish Quality Registry for Spine Surgery

BACKGROUND AND PURPOSE

Obesity has been associated with inferior outcomes after laminectomy due to central lumbar spinal stenosis (CLSS); we evaluated whether this occurs in surgery on national bases.

PATIENTS AND METHODS

We retrieved pre- and 1-year postoperative data from the National Swedish Quality Registry for Spine Surgery regarding patients aged ≥ 50 with laminectomy due to CLSS in 2005-2018. 4,069 patients had normal weight, 7,044 were overweight, 3,377 had class I obesity, 577 class II obesity, and 94 class III obesity ("morbid obesity"). Patient-reported outcome included satisfaction after 1 year, leg pain (Numerical Rating Scale [NRS], rating 0-10), disability (Oswestry Disability Index [ODI], rating 0-100). Complications were also retrieved.

RESULTS

1-year postoperatively, 69% of patient of normal weight, 67% who were overweight, and 62% with obesity (classes I-III aggregated) were satisfied (p < 0.001) and 62%, 60%, and 57% in obese groups I-III, respectively (p = 0.7). NRS leg pain improved in normal-weight patients by 3.5 (95% CI 3.4-3.6), overweight by 3.2 (CI 3.1-3.2), and obese by 2.6 (CI 2.5-2.7), and 2.8 (CI 2.7-2.9), 2.5 (CI 2.2-2.7), and 2.6 (CI 2.0-3.2) in obese classes I-III, respectively. ODI improved in normal weight by 19 (CI 19-20), overweight by 17 (CI 17-18), and obese by 14 (CI 13-15), and 16 (CI 15-17), 14 (CI 13-16), 14 (CI 11-18) in obese classes I-III, respectively. 8.1% of normal weight, 7.0% of overweight, and 8.1% of obese patients suffered complications (p = 0.04) and 8.1%, 7.0%, and 17% among obese classes I-III, respectively (p < 0.01).

CONCLUSION

Most obese patients are satisfied after laminectomy due to CLSS, even if satisfaction rate is inferior compared with normal-weight patients. The morbidly obese have more complications than patients with lower BMI.

Obesity Does Not Adversely Affect Long-term Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Matched Cohort Analysis

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is an established technique for the treatment of degenerative spine disease. The larger body habitus of obese patients increases the intraoperative complexity of MI-TLIF. Therefore, it is unclear whether this procedure is appropriate for this population. The goal of this study was to compare postoperative outcomes for obese patients vs nonobese patients undergoing MI-TLIF through a matched cohort analysis. A retrospective review was performed to identify patients who underwent MI-TLIF at a single institution with a minimum follow-up of 5 years. Patients were divided into 2 cohorts: nonobese (body mass index <30 kg/m²) and obese (body mass index ≥30 kg/m²). Each cohort was matched for age, sex, and levels operated. Perioperative data and patient-reported outcomes were compared. Radiographic outcomes were measured at final follow-up. Standard binomial and categorical comparative analyses were performed. A total of 148 patients were included. Of obese patients, 17.6% required revision surgery compared with 16.2% of nonobese patients (P=.826). Both cohorts had a similar proportion of pelvic incidence-lumbar lordosis mismatch correction (P=.780). Mean change in functional outcome scores for each cohort did not differ significantly. Obese patients had clinically minor but statistically significantly greater blood loss and longer operative times than nonobese patients (P<.001). Obese and non-obese patients undergoing MI-TLIF showed no long-term differences in revision rate, radiologic outcome, or functional outcome after long-term follow-up. Obese patients had slightly greater blood loss and longer operative times. Our findings suggest that MI-TLIF is an appropriate alternative to traditional open lumbar fusion for obese patients. [Orthopedics. 2022;45(4):203-208.].

Subcutaneous Fat Thickness on Erect Radiographs Is a Predictor of Infection Following Elective Posterior Lumbar Fusion

BACKGROUND

Posterior lumbar fusions are a common and successful procedure, yet surgical site infection (SSI) is still prevalent and causes significant morbidity. Obesity is a well-established risk factor for SSI. Still, the accuracy of the body mass index (BMI) caused some to suggest other metrics that are more representative of the thickness of the soft-tissue envelope in the surgical site.

METHODS

A retrospective review of all cases that developed SSI following posterior lumbar fusion over the past 5 years was done. An age and gender-matched control group was formed from the lumbar fusion cases that did not develop SSI. Demographic and clinical data were collected, and morphometric measurements of the soft-tissue envelope were performed at the level of L4 for all cases on standing x-ray imaging and magnetic resonance imaging (MRI).

RESULTS

A total of 366 patients underwent posterior lumbar fusion, 26 of whom developed SSI. BMI and skin to spinous process measurements on x-ray imaging-not MRI-were found to be significantly associated with SSI. Regression analysis further confirmed the strength of the association.

CONCLUSION

While BMI and MRI measurements are useful, wound depth measurements on x-ray imaging can be predictive of SSI in lumbar fusion cases.

CLINICAL RELEVACE

Wound depth measurements are predictive of lumbar wound infection. The information within this study can help surgeons better predict and manage infections of posterior lumbar wounds.

LEVEL OF EVIDENCE: 3

Do the benefits of hook-hybrid construct justify their use over all-pedicle screws constructs in maintaining postoperative curve correction for adolescent idiopathic scoliosis patients from an Asian population?

STUDY DESIGN

Retrospective study.

OBJECTIVE

(1) Compare outcomes of all-pedicle screws (PS) and hook-hybrid (H) constructs in adolescent idiopathic scoliosis (AIS) patients; and (2) investigate whether BMI, height or pedicle size may modify the effect of the type of surgical construct on the extent of curve decompensation.

METHODS

AIS patients who underwent surgical fixation with H or PS constructs at a single tertiary institution were reviewed. Patients with implant density of at least 70% and 2-year follow-up were included. Demographic and perioperative data collected were age, sex, height, BMI, implant density and pedicle diameter. Cobb's angles and curve correction were compared preoperatively, postoperatively and at follow-up.

RESULTS

In total, 59 patients were included. H group had a lower pedicle size at the highest level of construct and at T4 compared to PS group. Postoperatively, H group (30.2° ± 11.7°) and PS group (32.1° ± 10.4°) had similar correction (mean diff. 2.0°, p = 0.516). At 2-year follow-up, H group (1.6° ± 3.5°) and PS group (0.1° ± 2.8°) had similar curve deterioration (mean diff. 1.5°, p = 0.079). Uni- and multivariate analyses revealed that BMI and height were not associated with curve deterioration at 2-year follow-up among the H and PS groups.

CONCLUSION

H constructs provided similar maintenance of curve correction at 2-year follow-up compared to PS constructs. BMI and Stature did not modify curve deterioration between both groups at follow-up. This study supports the use of H constructs when faced with difficult pedicle morphology associated with shorter stature as it provides comparable and satisfactory long-term maintenance of curve correction.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Impact of Body Mass Index on Postsurgical Outcomes for Workers' Compensation Patients Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion

BACKGROUND

Increased morbidity associated with obesity imposes a greater financial burden on companies that provide insurance to their employees. Few studies have investigated the relationship between body mass index (BMI) and patient-reported outcome measures (PROMs) for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) in the workers' compensation (WC) population.

METHODS

WC patients who underwent a primary, single-level MIS TLIF were included/grouped according to BMI: nonobese (<30 kg/m2); obese I (≥30, <35 kg/m2); severe + morbid (≥35). PROMs were collected pre- and postoperatively: visual analog scale (VAS), Oswestry Disability Index (ODI), 12-Item Short Form (SF-12) physical composite score (PCS), and Patient-Reported Outcome Measurement Information System physical function (PROMIS-PF). BMI predictive power grouping on PROMs was evaluated using simple linear regression. Established minimum clinically important difference values were used to compute achievement rates across PROMs using logistic regression.

RESULTS

A total of 116 nonobese, 70 obese I, and 61 severe + morbid patients were included. Demographics among BMI grouping significantly differed in gender, hypertensive status, and American Society of Anesthesiologists score (P ≤ 0.037, all). Operative time was significantly different in perioperative values among BMI grouping (P ≤ 0.001). Increased BMI was significantly associated with greater VAS back at 12 weeks and 2 years (P ≤ 0.026, all), greater ODI preoperatively at 12 weeks and 6 months (P ≤ 0.015, all), and decreased PROMIS-PF at 12 weeks (P ≤ 0.011, all). Mean PROMs between obese I and severe + morbid cohorts differed in SF-12 PCS at 12 weeks, only (P = 0.050). ODI overall was the only parameter for which minimum clinically important difference was achieved among BMI cohorts (P ≤ 0.023).

CONCLUSION

WC patients with increased BMI were more likely to develop significant back pain and disability at numerous postoperative timepoints compared with nonobese individuals. Our findings highlight the weight management importance within WC population to minimize back pain and disability following MIS TLIF, but provide a sense of reassurance with comparable clinical improvement regardless of BMI.

CLINICAL RELEVANCE

When considering the effect of weight, surgeons may incorporate these findings in managing patient expectations in the WC population undergoing lumbar spine surgery.

LEVEL OF EVIDENCE: 3

Minimally invasive versus open lumbar spinal fusion: a matched study investigating patient-reported and surgical outcomes

OBJECTIVE

With the expanding indications for and increasing popularity of minimally invasive surgery (MIS) for lumbar spinal fusion, large-scale outcomes analysis to compare MIS approaches with open procedures is warranted.

METHODS

The authors queried the Quality Outcomes Database for patients who underwent elective lumbar fusion for degenerative spine disease. They performed optimal matching, at a 1:2 ratio between patients who underwent MIS and those who underwent open lumbar fusion, to create two highly homogeneous groups in terms of 33 baseline variables (including demographic characteristics, comorbidities, symptoms, patient-reported scores, indications, and operative details). The outcomes of interest were overall satisfaction, decrease in Oswestry Disability Index (ODI), and back and leg pain, as well as hospital length of stay (LOS), operative time, reoperations, and incidental durotomy rate. Satisfaction was defined as a score of 1 or 2 on the North American Spine Society scale. Minimal clinically important difference (MCID) in ODI was defined as ≥ 30% decrease from baseline. Outcomes were assessed at the 3- and 12-month follow-up evaluations.

RESULTS

After the groups were matched, the MIS and open groups consisted of 1483 and 2966 patients, respectively. Patients who underwent MIS fusion had higher odds of satisfaction at 3 months (OR 1.4, p = 0.004); no difference was demonstrated at 12 months (OR 1.04, p = 0.67). Lumbar stenosis, single-level fusion, higher American Society of Anesthesiologists Physical Status Classification System grade, and absence of spondylolisthesis were most prominently associated with higher odds of satisfaction with MIS compared with open surgery. Patients in the MIS group had slightly lower ODI scores at 3 months (mean difference 1.61, p = 0.006; MCID OR 1.14, p = 0.0495) and 12 months (mean difference 2.35, p < 0.001; MCID OR 1.29, p < 0.001). MIS was also associated with a greater decrease in leg and back pain at both follow-up time points. The two groups did not differ in operative time and incidental durotomy rate; however, LOS was shorter for the MIS group. Revision surgery at 12 months was less likely for patients who underwent MIS (4.1% vs 5.6%, p = 0.032).

CONCLUSIONS

In patients who underwent lumbar fusion for degenerative spinal disease, MIS was associated with higher odds of satisfaction at 3 months postoperatively. No difference was demonstrated at the 12-month follow-up. MIS maintained a small, yet consistent, superiority in decreasing ODI and back and leg pain, and MIS was associated with a lower reoperation rate.

Obesity and Workers' Compensation in the Setting of Minimally Invasive Lumbar Decompression

OBJECTIVE

To investigate the influence of body mass index (BMI) on perioperative outcomes, postoperative patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement among workers' compensation (WC) claimants undergoing minimally invasive lumbar decompression (MIS-LD).

METHODS

WC patients diagnosed with herniated nucleus pulposus undergoing single-level MIS-LD were identified. Patients were divided into 3 groups: Non-obese (<30 kg/m²), Obese I (≥30 and <35 kg/m²), and Obese II/III (≥35 kg/m²). PROMs were collected preoperatively and at 6 weeks, 12 weeks, 6 months, 1 year, and 2 years postoperatively. The predictive influence of BMI grouping on mean PROM scores was computed using simple linear regression. To compare PROMs between groups, post hoc pairwise comparisons of adjusted means were utilized. MCID achievement was compared between groups with χ² analysis.

RESULTS

A total of 81 patients were in the Non-obese cohort, and 43 and 45 in the Obese I and Obese II/III cohorts, respectively. Visual analog scale (VAS) leg, Oswestry Disability Index (ODI), and 12-Item Short Form Physical Composite Score (SF-12 PCS) were worse in the Obese I cohort at 12 weeks, and SF-12 PCS was lower in the Obese I vs. Obese II/III subgroup analysis (P ≤ 0.045, all). MCID achievement rates for ODI were higher for the Non-obese group at 12 weeks and overall (P ≤ 0.049, both). MCID attainment for VAS back was higher among the Non-obese cohort at 6-weeks (P = 0.022).

CONCLUSIONS

Patients with higher levels of obesity were more likely to experience longer length of stay and delayed discharge following MIS-LD. Increasing BMI was generally not a significant predictor of postoperative pain, disability, or physical health PROMs at most timepoints. MCID achievement rates for disability relief were significantly higher for non-obese patients.

Decompression and Interlaminar Stabilization for Lumbar Spinal Stenosis: A Cohort Study and Two-Dimensional Operative Video

Background and Objectives: Lumbar spinal stenosis is one of the most common causes of disability in the elderly and often necessitates surgical intervention in patients over the age of 65. Our study aimed to evaluate the clinical efficacy of interlaminar stabilization following decompressive laminectomy in patients with lumbar stenosis without instability. Materials and Methods: Twenty patients with lumbar stenosis underwent decompressive laminectomy and interlaminar stabilization at our academic institution. Clinical outcomes were measured using the visual analog scale (VAS) and Oswestry disability index (ODI) at the 2-month, 6-month, and 1-year postoperative visits, and these outcomes were compared to the preoperative scores. Results: The average VAS scores for low back pain significantly improved from 8.8 preoperatively to 4.0, 3.7, and 3.9 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). The average VAS scores for lower extremity pain significantly improved from 9.0 preoperatively to 2.7, 2.5, and 2.5 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). The average ODI scores significantly improved from 66.6 preoperatively to 23.8, 23.3, and 24.5 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). There was no statistical significance for difference in VAS or ODI scores between 2 months, 6 months, and 1 year. One patient had an intraoperative durotomy that was successfully treated with local repair and lumbar drainage. Another patient had progression of stenosis and had to undergo bilateral facetectomy and fusion. Conclusions: Decompressive laminectomy and interlaminar stabilization in patients with spinal claudication and low back pain is a good surgical option in the absence of instability and may provide significant clinical improvement of pain and functional disability.

A Study Investigating Whether BMI Is Associated With Acetabular Bone Size: Big Bones or a Big Myth?

Background

There is a common conception held by patients with a high body mass index (BMI) that they have “big bones”. Some people hold the assumption that their weight is attributed to larger bone stock rather than adipose tissue. It was the suspicion of the surgeons at our unit that this is often not the case. We therefore conducted a study investigating if there is any association between BMI and acetabular bone size.

Methods

We conducted a retrospective chart review of all patients undergoing total hip arthroplasty using the Trident acetabular system from Stryker at our tertiary level 1 trauma centre between September 2016 and August 2020. Patient demographic and surgical data were collected, and the association of BMI, height, and weight, with acetabular cup size was investigated using Pearson’s correlation coefficient and chi-square test for independence.

Results

A total of 418 patients were included in this study (52.4% female; age: 20-93 years; mean age: 62.51 years), with a mean BMI of 29.55 kg/m²(range: 14.95-52.32 kg/m²). A weak positive association between BMI and cup size, which was statistically significant (r = 0.107; n = 418; p = 0.02). The chi-square test for independence was used to study the association between obesity and cup size (large vs small), which demonstrated no significant difference (p = 0.08). There was a moderately strong positive association between height and cup size (r = 0.551; n = 418; p < 0.01). There was a weak positive association between weight and cup size, which was statistically significant (r = 0.355; n = 418; p < 0.01).

Conclusion

Our study suggests that there is indeed a weakly positive linear association between BMI and cup size among total hip arthroplasty patients. This effect was, however, more significant for height and weight, and there was no significant association between obese and non-obese groups with small versus large cup size implanted. We therefore conclude that clinically there is no significant relationship between obesity and acetabular bone size and that the “big bones” claim is indeed fallacious.

The Role of Nutrition in Degenerative Cervical Myelopathy: A Systematic Review

Introduction

Degenerative cervical myelopathy (DCM) is the commonest cause of adult spinal cord impairment worldwide, encompassing chronic compression of the spinal cord, neurological disability and diminished quality of life. Evidence on the contribution of environmental factors is sparse; in particular, the role of nutrition in DCM is unknown. The objective of this review was to assess the effect of nutrition on DCM susceptibility, severity and surgical outcome.

Methods

A systematic review in MEDLINE and Embase was conducted following PRISMA guidelines. Full-text papers in English papers, focussing on cervical myelopathy and nutrition, published before January 2020 were considered eligible. Quality assessments were performed using the GRADE assessment tool. Patient demographics, nutritional factor and DCM outcomes measures were recorded. Relationships between nutritional factors, interventions and disease prognosis were assessed.

Results

In total, 5835 papers were identified of which 44 were included in the final analysis. DCM patients with pathological weight pre-operatively were more likely to see poorer improvements post-surgically. These patients experienced poorer physical and mental health improvements from surgery compared to normal weight patients and were more likely to suffer from post-operative complications such as infection, DVT, PE and hospital readmissions. Two trials reporting benefits of nutritional supplements were identified, with 1 suggesting Cerebrolysin to be significant in functional improvement. An unbalanced diet, history of alcohol abuse and malnourishment were associated with poorer post-operative outcome.

Conclusion

Although the overall strength of recommendation is low, current evidence suggests nutrition may have a significant role in optimising surgical outcome in DCM patients. Although it may have a role in onset and severity of DCM, this is a preliminary suggestion. Further work needs to be done on how nutrition is defined and measured, however, the beneficial results from studies with nutritional interventions suggest nutrition could be a treatment target in DCM.

Racial Disparities in Outcomes After Spine Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

Racial disparities are a major issue in health care but the overall extent of the issue in spinal surgery outcomes is unclear. We conducted a systematic review/meta-analysis of disparities in outcomes among patients belonging to different racial groups who had undergone surgery for degenerative spine disease.

METHODS

We searched Ovid MEDLINE, Scopus, Cochrane Review Database, and ClinicalTrials.gov from inception to January 20, 2021 for relevant articles assessing outcomes after spine surgery stratified by race. We included studies that compared outcomes after spine surgery for degenerative disease among different racial groups.

RESULTS

We found 30 studies that met our inclusion criteria (28 articles and 2 published abstracts). We included data from 20 cohort studies in our meta-analysis (3,501,830 patients), which were assessed to have a high risk of observation/selection bias. Black patients had a 55% higher risk of dying after spine surgery compared with white patients (relative risk [RR], 1.55, 95% confidence interval [CI], 1.28-1.87; I² = 70%). Similarly, black patients had a longer length of stay (mean difference, 0.93 days; 95% CI, 0.75-1.10; I² = 73%), and higher risk of nonhome discharge (RR, 1.63; 95% CI, 1.47-1.81; I² = 89%), and 30-day readmission (RR, 1.45; 95% CI, 1.03-2.04; I² = 96%). No significant difference was noted in the pooled analyses for complication or reoperation rates.

CONCLUSIONS

Black patients have a significantly higher risk of unfavorable outcomes after spine surgery compared with white patients. Further work in understanding the reasons for these disparities will help develop strategies to narrow the gap among the racial groups.

Incidence and Risk Factors for Postoperative Venous Thromboembolic Events in Patients Undergoing Cervical Spine Surgery

STUDY DESIGN

This was a retrospective database study.

OBJECTIVE

The objective of this study was to investigate preoperative risk factors and incidence of venous thromboembolic events (VTEs) after cervical spine surgery.

SUMMARY OF BACKGROUND DATA

VTEs are preventable complications that may occur after spinal procedures. Globally, VTEs account for a major cause of morbidity and mortality. Preoperative risks factors associated with increased VTE incidence after cervical spine surgery have not been well-characterized.

MATERIALS AND METHODS

Patients undergoing anterior cervical discectomy and fusion (ACDF); posterior cervical fusion (PCF); discectomy; and decompression from 2007 to 2017 were identified using the PearlDiver Database. International Classification of Diseases (ICD) Ninth and 10th Revision codes were used to identify VTEs at 1 week, 1 month, and 3 months postoperative as well as preoperative risk factors.

RESULTS

Risk factors with the highest incidence of VTE at 3 months were primary coagulation disorder [ACDF=7.82%, odds ratio (OR)=3.96; decompression=11.24%, OR=3.03], central venous line (ACDF=5.68%, OR=2.11; PCF=12.58%, OR=2.27; decompression=10.17%, OR=2.80) and extremity paralysis (ACDF=6.59%, OR=2.73; PCF=18.80%, OR=2.99; decompression=11.86, OR=3.74). VTE incidence at 3 months for populations with these risks was significant for all surgery types (P<0.001) with the exception of patients with primary coagulation disorder who underwent PCF. Tobacco use had the lowest VTE incidence for all surgery types.

CONCLUSIONS

The total cumulative incidence of VTEs at 3-month follow-up was 3.10%, with the highest incidence of VTEs occurring within the first postoperative week (0.65% at 1 wk, 0.61% at 1 mo, 0.53% at 3 mo for ACDF; 2.56% at 1 wk, 1.93% at 1 mo, 1.45% at 3 mo for PCF; 1.37% at 1 wk, 0.93% at 1 mo, 0.91% at 3 mo for decompression). Several preoperative risk factors were found to be significant predictors for postoperative VTEs and can be used to suggest those at increased risk as well as decrease the incidence of preventable VTEs after cervical spine surgery.

LEVEL OF EVIDENCE

Level III.

Does minimally invasive spine surgery improve outcomes in the obese population? A retrospective review of 1442 degenerative lumbar spine surgeries

OBJECTIVE

The effect of obesity on outcomes in minimally invasive surgery (MIS) approaches to posterior lumbar surgery is not well characterized. The authors aimed to determine if there was a difference in operative variables and complication rates in obese patients who underwent MIS versus open approaches in posterior spinal surgery, as well as between obese and nonobese patients undergoing MIS approaches.

METHODS

A retrospective review of all consecutive patients who underwent posterior lumbar surgery from 2013 to 2016 at a single institution was performed. The primary outcome measure was postoperative complications. Secondary outcome measures included estimated blood loss (EBL), operative time, the need for revision, and hospital length of stay (LOS); readmission and disposition were also reviewed. Obese patients who underwent MIS were compared with those who underwent an open approach. Additionally, obese patients who underwent an MIS approach were compared with nonobese patients. Bivariate and multivariate analyses were carried out between the groups.

RESULTS

In total, 423 obese patients (57.0% decompression and 43.0% fusion) underwent posterior lumbar MIS. When compared with 229 obese patients (56.8% decompression and 43.2% fusion) who underwent an open approach, patients in both the obese and nonobese groups who underwent MIS experienced significantly decreased EBL, LOS, operative time, and surgical site infections (SSIs). Of the nonobese patients, 538 (58.4% decompression and 41.6% fusion) underwent MIS procedures. When compared with nonobese patients, obese patients who underwent MIS procedures had significantly increased LOS, EBL, operative time, revision rates, complications, and readmissions in the decompression group. In the fusion group, only LOS and disposition were significantly different.

CONCLUSIONS

Obese patients have poorer outcomes after posterior lumbar MIS when compared with nonobese patients. The use of an MIS technique can be of benefit, as it decreased EBL, operative time, LOS, and SSIs for posterior decompression with or without instrumented fusion in obese patients.

Preoperative PROMIS Scores Predict Postoperative Outcomes in Lumbar Spine Surgery Patients

STUDY DESIGN

Retrospective case series.

OBJECTIVE

Our objective was to examine the ability of preoperative Patient-reported Outcomes Measurement Information System (PROMIS) scores to predict postoperative achievement of a minimum clinically important difference (MCID) in outcome scores following lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

PROMIS is a computer adaptive testing system that has been validated in spine surgery patients. PROMIS allows for more efficient and personalized data collection compared to legacy assessment tools.

METHODS

A total of 138 patients who underwent lumbar spine surgery at a single institution completed PROMIS Physical Function (PF) and Pain Interference (PI) scores preoperatively and at 3, 12, and 24 months postoperatively. Univariate and multivariate analyses of PROMIS scores and clinical factors were performed. Receiver-operating characteristic curves were calculated to determine the ability of preoperative scores to predict postoperative achievement of an MCID of 8. PF and PI t score MCID achievement threshold values with 90% specificity were calculated.

RESULTS

Preoperative PROMIS PF and PI scores were significantly correlated to achievement of postoperative MCID after multivariate analysis. Patients with worse preoperative scores were more likely to achieve MCID. Preoperative PF and PI scores showed strong predictive value in determining ability to achieve postoperative MCID with respective area under the curve of 0.85 and 0.82. A preoperative PF threshold T-score of 31.6 had a 64% chance of achieving postoperative MCID, while a preoperative PI threshold t score of 67.8 had an 86% chance of achieving postoperative MCID.

CONCLUSION

Preoperative PROMIS PF and PI scores predicted improvement in postoperative PROMIS scores in lumbar spine surgery patients as worse preoperative scores correlated to improved PROMIS scores postoperatively. The calculated threshold t scores showed the ability to predict improvement in postoperative PROMIS scores. Preoperative PROMIS data may be useful in surgical decision-making and improved patient education regarding postoperative outcomes.Level of Evidence: 4.

An Assessment of Nonoperative Management Strategies in a Herniated Lumbar Disc Population: Successes Versus Failures

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare the utilization of conservative treatments in patients with lumbar intervertebral disc herniations who were successfully managed nonoperatively versus patients who failed conservative therapies and elected to undergo surgery (microdiscectomy).

METHODS

Clinical records from adult patients with an initial herniated lumbar disc between 2007 and 2017 were selected from a large insurance database. Patients were divided into 2 cohorts: patients treated successfully with nonoperative therapies and patients that failed conservative management and opted for microdiscectomy surgery. Nonoperative treatments utilized by the 2 groups were collected over a 2-year surveillance window. "Utilization" was defined by cost billed to patients, prescriptions written, and number of units disbursed.

RESULTS

A total of 277 941 patients with lumbar intervertebral disc herniations were included. Of these, 269 713 (97.0%) were successfully managed with nonoperative treatments, while 8228 (3.0%) failed maximal nonoperative therapy (MNT) and underwent a lumbar microdiscectomy. MNT failures occurred more frequently in males (3.7%), and patients with a history of lumbar epidural steroid injections (4.5%) or preoperative opioid use (3.6%). In a logistic multivariate regression analysis, male sex and utilization of opioids were independent predictors of conservative management failure. Furthermore, a cost analysis indicated that patients who failed nonoperative treatments billed for nearly double ($1718/patient) compared to patients who were successfully treated ($906/patient).

CONCLUSION

Our results suggest that the majority of patients are successfully managed nonoperatively. However, in the subset of patients that fail conservative management, male sex and prior opioid use appear to be independent predictors of treatment failure.

Effect of Surgical Setting on Cost and Hospital Reported Outcomes for Single-Level Anterior Cervical Discectomy and Fusion

BACKGROUND

Hospitals seek to reduce costs and improve patient outcomes by decreasing length of stay (LOS), 30-day all-cause readmissions, and preventable complications. We evaluated hospital-reported outcome measures for elective single-level anterior cervical discectomy and fusions (ACDFs) between tertiary (TH) and community hospitals (CH) to determine location-based differences in complications, LOS, and overall costs.

METHODS

Patients undergoing elective single-level ACDF in a 1-year period were retrospectively reviewed from a physician-driven database from a single medical system consisting of 1 TH and 4 CHs. Adult patients who underwent elective single-level ACDF were included. Patients with trauma, tumor, prior cervical surgery, and infection were excluded. Outcomes measures included all-cause 30-day readmissions, preventable complications, LOS, and hospital costs.

RESULTS

A total of 301 patients (60 TH, 241 CH) were included. CHs had longer LOS (1.25 ± 0.50 versus 1.08 ± 0.28 days, P = .01). There were no differences in complication and readmission rates between hospital settings. CH, orthopaedic subspecialty, female sex, and myelopathy were predictors for longer LOS. Overall, costs at the TH were significantly higher than at CHs ($17 171 versus $11 737; Δ$ = 5434 ± 3996; P < .0001). For CHs, the total costs of drugs, rooms, supplies, and therapy were significantly higher than at the TH. TH status, orthopaedic subspecialty, and myelopathy were associated with higher costs.

CONCLUSION

Patients undergoing single-level ACDFs at CHs had longer LOS, but similar complications and readmission rates as those at the TH. However, cost of ACDF was 1.5 times greater in the TH. To improve patient outcomes, optimize value, and reduce hospital costs, modifiable factors for elective ACDFs should be evaluated.

LEVEL OF EVIDENCE

3.

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

STUDY DESIGN

This was a national database study.

OBJECTIVE

The objective of this study was to assess the impact of prior bariatric surgery (BS) on altering 90-day postoperative outcomes following elective anterior cervical discectomy and fusions (ACDFs).

SUMMARY OF BACKGROUND DATA

Though obesity has previously been shown to be linked with adverse outcomes following elective spine surgical procedures, the effectiveness of weight-loss strategies such as BS has not been explored.

METHODS

The PearlDiver program was used to query the 2007-2013 100% Medicare Standard Analytical Files (SAF100) for patients undergoing an elective ACDF. The study cohort was divided into 2 groups-(1) obese ACDF patients (body mass index ≥35 kg/m 2 ) receiving a BS procedure within 2 years before an ACDF and (2) obese ACDF patients (body mass index ≥35 kg/m 2 ) without a known history of a BS procedure within the last 2 years. Multivariate regression analyses were used to assess the impact of a BS procedure on postoperative outcomes following ACDF while adjusting for age, sex, region, and Elixhauser Comorbidity Index.

RESULTS

A total of 411 ACDF patients underwent BS within the 2 years before an ACDF. Multivariate analysis showed that undergoing BS before an elective ACDF was associated with a significantly reduced risk of pulmonary complications [odds ratio (OR)=0.53; P =0.002], cardiac complications (OR=0.69; P =0.012), sepsis (OR=0.69; P =0.035), renal complications (OR=0.54; P =0.044), and 90-day readmissions (OR=0.53; P =0.015).

CONCLUSIONS

Surgery-induced weight loss before an ACDF in obese patients is associated with reduced 90-day complication and readmission rates. Orthopaedic and bariatric surgeons should counsel obese patients on the benefits of BS following ACDFs.

Impact of body mass index on opioid consumption in lumbar spine fusion surgery

Background

in the United States from 1999 to 2000 through 2017–2018, the prevalence of obesity increased from 30.5 to 42.4%, while the prevalence of severe obesity nearly doubled. In lumbar spine surgery, obesity is associated with increased complications, worse perioperative outcomes, and higher costs. The purpose of this study was to examine the association between body mass index (BMI) and opioid consumption in patients undergoing lumbar spine fusion surgery. We hypothesized that obese patients would require more opioids postoperatively.

Methods

retrospective review of 306 patients who underwent one- or two-level posterior lumbar interbody fusion surgery between 2016 and 2020. Patients were stratified by BMI as follows: normal weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2), obese I (30.0–34.9 kg/m2), and obese II–III (≥ 35.0 kg/m2). Patient demographics and preoperative characteristics were compared across BMI cohorts using one-way ANOVA and chi-square analysis. Patients with prior history of opioid use were excluded. Primary outcome measure was postoperative opioid consumption. Secondary outcomes included operative time, length of stay (LOS), discharge destination, and 30-day re-encounter rates. Outcomes were analyzed using multivariable linear regression adjusted for potential confounders.

Results

of 306 total patients, 17.3% were normal weight, 39.9% were overweight, 25.5% were obese I, and 17.3% were obese II–III. Obesity was associated with longer operative times and length of stay (p < 0.001, p = 0.024). For opioid naïve patients, there was no difference in-house opioid consumption when adjusted for kilograms of body mass and LOS (p = 0.083). Classes II–III patients were prescribed more than twice the number of postoperative opioids (p < 0.001) and were on opioids for a longer time postoperatively (p = 0.019).

Conclusion

obesity is associated with longer operative times, longer LOS, and increased consumption of postoperative opioids. This should be considered when counseling patients preoperatively prior to lumbar spine fusion procedures.

The influence of modifiable risk factors on short-term postoperative outcomes following cervical spine surgery: A retrospective propensity score matched analysis

BACKGROUND

Modifiable risk factors (MRFs) represent patient variables associated with increased complication rates that may be prevented. There exists a paucity of studies that comprehensively analyze MRF subgroups and their independent association with postoperative complications in patients undergoing cervical spine surgery. Therefore, the purpose of this study is to compare outcomes between patients receiving cervical spine surgery with reported MRFs.

METHODS

Retrospective analysis of the Nationwide Readmissions Database (NRD) from the years 2016 and 2017, a publicly available and purchasable data source, to include adult patients undergoing cervical fusion. MRF cohorts were separated into three categories: substance abuse (alcohol, tobacco/nicotine, opioid abuse); vascular disease (hypertension, dyslipidemia); and dietary factors (malnutrition, obesity). Three-way nearest-neighbor propensity score matching for demographics, hospital, and surgical characteristics was implemented.

FINDINGS

We identified 9601 with dietary MRFs (D-MRF), 9654 with substance abuse MRFs (SA-MRF), and 9503 with vascular MRFs (V-MRF). Those with d-MRFs had significantly higher rates of medical complications (9.3%), surgical complications (8.1%), and higher adjusted hospital costs compared to patients with SA-MRFs and V-MRFs. Patients with d-MRFs (16.3%) and V-MRFs (14.0%) were independently non-routinely discharged at a significantly higher rate compared to patients with SA-MRFs (12.6%) (p<0.0001 and p = 0.0037). However, those with substance abuse had the highest readmission rate and were more commonly readmitted for delayed procedure-related infections.

INTERPRETATION

A large proportion of patients who receive cervical spine surgery have potential MRFs that uniquely influence their postoperative outcomes. A thorough understanding of patient-specific MRF subgroups allows for improved preoperative risk stratification, tailored patient counseling, and postoperative management planning.

FUNDING

None.

Identifying risks factors in thoracolumbar anterior fusion surgery through predictive analytics in a nationally representative inpatient sample

PURPOSE

Anterior thoracolumbar (TL) surgical approaches provide more direct trajectories compared to posterior approaches. Proper patient selection is key in identifying populations that may benefit from anterior TL fusion. Here, we utilize predictive analytics to identify risk factors in anterior TL fusion in patients with trauma and deformity.

METHODS

In this retrospective cohort study of patients receiving anterior TL fusion (between and including T12/L1), population-based regression models were developed to identify risk factors using the National Readmission Database 2016-2017. Readmissions were analyzed at 30- and 90-day intervals. Risk factors included hypertension, obesity, malnutrition, smoking, alcohol use, long-term opioid use, and frailty. Multivariate regression models were developed to determine the influence of each risk factor on complication rates.

RESULTS

A total of 265 and 375 patients were identified for the scoliosis and burst fracture cohorts, respectively. In patients with scoliosis, alcohol use was found to increase the length of stay (LOS) (p = 0.00061) and all-payer inpatient cost following surgery (p = 0.014), and frailty was found to increase the inpatient LOS (p = 0.0045). In patients with burst fractures, malnutrition was found to increase the LOS (p < 0.0001) and all-payer cost (p < 0.0001), obesity was found to increase the all-payer cost (p = 0.012), and frailty was found to increase the all-payer cost (p = 0.031) and LOS (p < 0.0001).

DISCUSSION

Patient-specific risk factors in anterior TL fusion surgery significantly influence complication rates. An understanding of relevant risk factors before surgery may facilitate preoperative patient selection and postoperative patient triage and risk categorization.

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.

Adolescent Disc Disease: Risk Factors and Treatment Success-Related Factors

OBJECTIVE

A paucity of literature is available discussing the associated risk factors, treatment options (including the use of minimally invasive surgery), and outcomes related to lumbar disc herniation (LDH) in children. We have discussed the risk factors for disc disease among pediatric patients and evaluated the efficacy of the minimally invasive approach.

METHODS

A retrospective review of pediatric patients with lumbar disc disease who had undergone microdiscectomy at our institution from 2005 to 2016 was conducted. The preoperative presentation, hospital course, postoperative course, and follow-up data (≥3 years) were reviewed. We evaluated the risk factors for LDH and the surgical outcomes for both groups.

RESULTS

A total of 52 pediatric patients had undergone 61 lumbar disc surgeries for LDH in our department from 2005 to 2016. Their average age at surgery was 16.65 years. Of the 61 procedures, 48 (78.7%) had been performed via the minimally invasive spine microdiscectomy approach and 13 (21.3%) via the open microdiscectomy approach. The average body mass index for all cases was 29.3 kg/m². The average interval to diagnosis was 7.9 months. Of the 61 cases, 21 (34.4%) had been required for patients who were competitive athletes. In addition, 15 had been for LDH related to trauma (24.6%). In 46 of the 61 cases, complete resolution of the symptoms had occurred at the 1-year follow-up visit (79.2% of minimally invasive spine microdiscectomy vs 61.5% of open microdiscectomy).

CONCLUSION

Risk factors similar to those for adult LDH, such as an elevated body mass index, can be seen in the pediatric population. However, some unique risk factors such as post-traumatic LDH were found in the pediatric age group. Minimally invasive techniques are demonstrably safe and useful in this patient population.

Influence of dynamic preoperative body mass index changes on patient-reported outcomes after surgery for degenerative lumbar spine disease

Psychological factors demonstrably and often massively influence outcomes of degenerative spine surgery, and one could hypothesize that preoperative weight loss may correlate with motivation and lifestyle adjustment, thus leading to potentially enhanced outcomes. We aimed to evaluate the effect of preoperative weight loss or gain, respectively, on patient-reported outcomes after lumbar spine surgery. Weight loss was defined as a BMI decrease of ≤ − 0.5 kg/m² over a period of at least 1 month, and weight gain as a BMI increase of ≥ 0.5 kg/m² in the same time period, respectively. The primary endpoint was set as the achievement of the minimum clinically important difference (MCID) in the ODI at 1 or 2 years postoperatively. A total of 154 patients were included. Weight loss (odds ratio (OR): 1.18, 95% confidence interval (CI): 0.52 to 2.80) and weight gain (OR: 1.03, 95% CI: 0.43 to 2.55) showed no significant influence on MCID achievement for ODI compared to a stable BMI. The same results were observed when analysing long-term NRS-BP and NRS-LP. Regression analysis showed no correlation between BMI change and PROM change scores for any of the three PROMs. Adjustment for age and gender did not alter results. Our findings suggest that both preoperative weight loss and weight gain may have no measurable effect on long-term postoperative outcome compared to a stable BMI. Weight loss preoperatively—as a potential surrogate sign of patient motivation and lifestyle change—may thus not influence postoperative outcomes.