Comparison of a Posterior versus Anterior Approach for Lumbar Interbody Fusion Surgery Based on Relative Value Units

The current value-driven healthcare system encourages physicians to continuously optimize the value of the services they provide. Relative value units (RVUs) serve as the basis of a reimbursement model linking the concept that as the effort and value of services provided to patient's increases, physician reimbursement should increase proportionately. Spine surgery is particularly affected by these factors as there are multiple ways to achieve similar outcomes, some of which require more time, effort, and risk. Specifically, as the trend of spinal interbody fusion has increased over the past decade, the optimal approach to use-posterior versus anterior lumbar interbody fusion (PLIF vs. ALIF)-has been a source of controversy. Due to potential discrepancies in effort, one factor to consider is the correlation between RVUs and the time needed to perform a procedure. Therefore, the purpose of this study was to compare: 1) mean RVUs; 2) mean operative time; and 3) mean RVUs per unit of time between PLIF and ALIF with the utilization of a national surgical database. We also performed an individual surgeon cost benefit analysis for performing PLIF versus ALIF.

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was utilized to identify 6,834 patients who underwent PLIF (CPT code: 22630) and 6,985 patients who underwent ALIF (CPT code: 22558) between 2008 and 2015. The mean operative times (in minutes), mean RVUs, and RVUs per minute were calculated and compared using the Student's t-tests. In addition, the reimbursement amount (in dollars) per minute, case, day, and year for an individual surgeon performing PLIF versus ALIF were also calculated and compared. A p-value of less than 0.05 was used as the threshold for statistical significance.

Compared to ALIF cases, PLIF cases had longer mean operative times (203 vs. 212 minutes, p<0.001). However, PLIF cases were assigned lower mean RVUs than ALIF cases (22.08 vs. 23.52, p<0.001). Furthermore, PLIF had a lower mean RVU/minutes than ALIF cases (0.126 vs. 0.154, p<0.001). The reimbursement amounts calculated for PLIF versus ALIF were: $4.52 versus $5.53 per minute, $958.66 versus $1,121.95 per case, and $2,875.98 versus $3,365.86 per day. The annual cost difference was $78,380.92.

The data from this study indicates a potentially greater annual compensation of nearly $80,000 for performing ALIF as opposed to PLIF due to a higher "hourly rate" for ALIF as is noted by the significantly greater RVU per minute (0.154 vs. 0.126 RVU/minutes). These results can be used by spine surgeons to design more appropriate compensation effective practices while still providing quality care.