Obesity: An Independent Risk Factor for Complications in Anterior Lumbar Interbody Fusion? A Systematic Review

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

Cerebrospinal fluid (CSF) leak after elective lumbar spinal fusion: Who is at risk?

PURPOSE

CSF leaks are a known complication of lumbar fusion surgery. There is a scarcity of literature describing the incidence and risk factors associated with this complication. The aim of this study was to identify patients who are at risk of developing postoperative CSF leak.

METHODS

The Nationwide Inpatient Sample database was used to identify patients who had lumbar fusion in the US from 2002 to 2014. Inpatient outcomes included the incidence and risk of developing CSF leak based on selected patient-specific characteristics. Secondary outcomes included average length of stay, mean costs, and mortality rates. All statistical analyses were conducted based on multivariate regression models using the SPSS software.

RESULTS

A total of 439,220 patients who underwent elective lumbar fusion procedures were identified. Of these patients, 2.6% (11,636 /439,220) were found to have CSF leak. Independent important risk factors for CSF leak development included: older age (OR: 1.025; 95% CI: 1.02-1.03; p < 0.0001), posterior approach (OR: 1.71; 95% CI: 1.59-1.85; p < 0.0001) compared to anterior approach, chronic deficiency anemia (OR: 1.21; 95% CI:1.14-1.30; p < 0.0001), obesity (OR: 1.22; 95% CI: 1.15-1.30; p < 0.0001), and pulmonary circulatory disease (OR: 1.44; 95% CI: 1.18-1.75; p < 0.0001). CSF leak was associated with increased length of stay (5.39 ± 3.86 vs. 3.74 ± 2.55; p < 0.0001), hospitalization costs (120,129.0 ± 88,123.5 vs. 89,226.8 ± 65,350.3; p < 0.0001) and mortality (0.3% vs. 0.1%; p < 0.05).

CONCLUSION

Spine surgeons should be aware of certain patient and procedure-specific characteristics that increase the risk of developing postoperative CSF leak after lumbar fusion in order to improve patient outcomes.