Surgical Survivorship of Lumbar Diskectomy in Patients with Workman’s Compensation Claims

Presented at SMISS Annual Forum 2014
By Kern Singh MD
With Sreeharsha V. Nandyala BA, Alejandro Marquez-Lara MD, Islam Elboghdady , Eric Sundberg MD, Hamid Hassanzadeh MD, Anton Jorgensen MD, Khaled Aboushaala MD, Junyoung Ahn ,

Disclosures: Kern Singh MD A; CSRS Resident Grant. B; DePuy, Zimmer, Stryker, CSRS, ISASS, AAOS, SRS, Vertebral Column - ISASS. D; Avaz Surgical, LLC, Vital 5, LLC. F; Zimmer, Stryker, Pioneer, Lippincott Williams & Wilkins, Th Sreeharsha Nandyala BA None, Alejandro Marquez-Lara MD None, Islam Elboghdady None, Eric Sundberg MD None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Khaled Aboushaala MD None, Junyoung Ahn None,

Introduction:
Workman’s compensation (WC) patients are perceived to carry worsened outcomes after lumbar spine surgery compared to more traditional patients. The purpose of this study is to analyze the one-year survival associated with WC claims after a minimally invasive (MIS) lumbar diskectomy, with revision surgery as the end-point.

Aims/Objectives:
To assess the impact of Workman’s compensation claims on the surgical survivorship associated with minimally invasive 1 and 2 level lumbar diskectomies.

Methods:
A retrospective review of 251 patients who underwent a primary 1 or 2 level MIS lumbar diskectomy between 2007-2013 was performed. Non-elective admissions, and patients without a documented one-year follow up visit were excluded from the analysis. The selected cohort was stratified based upon primary payor status (WC and non-WC) and assessed with regards to demographics, Charlson comorbidity index (CCI), and body mass index (BMI). The incidence and prevalence of revision surgeries at 12-months were calculated by the Kaplan-Meier method. Survival distributions were analyzed with the Log-Rank comparison test and a p-value of <0.05 was utilized to denote statistical significance.

Results:
Of the 192 patients included in this analysis, 77 (40.1%) carried WC as the primary insurance. There were no significant differences in patient age (40.1±10.4 vs 42.5±14.6, p=0.21), and comorbidity burden (CCI: 1.48±1.69 vs 1.24±1.52, p=0.43) between the two cohorts. However, WC patients demonstrated a lower body mass index (BMI: 28.6±6.6 vs 30.9±6.3, p<0.05). Overall 26 (13.6%) patients required a revision surgery for persistent or worsening symptoms within 12-months of the index lumbar diskectomy. Kaplan-Meier analysis predicted a significantly lower one-year survival in the WC cohort compared to the non-WC cohort (74.0% (n=57/77) vs 94.8% (n=109/115); Log-Rank: Chi-square 17.18, p<0.001). In addition, WC patients who required a revision surgery more often underwent a lumbar fusion compared to non-WC revisions (65.0% vs 16.7%, p<0.05).

Conclusions:
This retrospective survival analysis demonstrated that WC insurance is associated with higher rates of revision surgery after MIS lumbar diskectomy procedures. The greater occupational physical demand in WC claimants may explain these higher rates of failure. With roughly 1 out of every 4 (26%) WC patients requiring a reoperation, further studies are warranted to help reduce the rate of revision surgery in this challenging population.