Functional Outcomes in Workman's Compensation Patients Following Transforaminal Lumbar Interbody Fusion

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

Disclosures: Abbas Naqvi BS None 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,

Introduction:
Functional capacity evaluations (FCE) are a method to determine the level of functioning in WC patients. The ability to meet pre-injury job demands following an MIS TLIF procedure in this challenging patient population has not been previously described.

Aims/Objectives:
To analyze the clinical and functional outcomes following a single-level minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) in Workman’s compensation (WC) patients.

Methods:
155 WC patients who underwent a primary single-level MIS TLIF procedure between 2007-2013 were analyzed. Patient demographics, comorbidity burden (CCI), smoking status, intraoperative parameters, length of hospitalization, visual analogue scale (VAS) scores, and one-year arthrodesis rates were assessed. A subgroup analysis of patients with available FCE records was performed to compare outcomes between patients who met and did not meet job requirements. Statistical analysis was performed with chi-squared test for categorical variables and Student-Test for continuous variables. A p-value of <0.05 denoted statistical significance.

Results:
The mean age, CCI, and preoperative VAS scores were 45.0 years (±10.2), 1.41 (±1.22), and 7.0 (±1.7) respectively. Of the 107 patients with available FCEs, 29 patients (27.1%) met pre-injury job demands. There were no significant differences in demographics, comorbidity burden, intraoperative parameters, or preoperative VAS scores between cohorts. Patients who did not meet job requirements demonstrated lower one-year arthrodesis rates (83.3% vs. 100%, p<0.05), greater 6-month VAS scores (5.0±2.2 vs. 3.8±2.5, p<0.05), and higher rates of revision surgery (35.1% vs. 6.9%, p<0.05) compared to those who did meet job requirements. WC patients who did not meet job requirements demonstrated a higher proportions of medium (56.4% vs. 34.5%, p<0.05), heavy (34.6% vs. 24.1%, p<0.05), and very heavy (7.7% vs. 3.4%, p<0.05) pre-operative job requirements. Patients who met job demands demonstrated significantly greater ultimate work levels (heavy: 34.5% vs. 2.6%; very heavy: 3.4% vs. 0.0%; p<0.05).

Conclusions:
Patients with light or medium job demands were more likely to meet or surpass job requirements following an MIS TLIF. Patients with jobs requiring a level of functioning greater than medium were less likely to return their original job. Although further studies are warranted, these findings suggest that patients with higher preoperative job requirements are less likely to regain pre-injury functional capacity following an MIS TLIF procedure.