Objective:

While visual analogue score (VAS) metrics are among the most universally adopted patient-reported outcome measures (PROMs), there is limited research on the influence of back and leg pain on the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) scores. Here we assess the association of VAS back and VAS leg scores with PROMIS PF in the setting of minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Secondarily, we determine if PROMIS PF is more influenced by back or leg pain.

Methods:

A prospective surgical registry was reviewed from May 2015 to November 2018. Inclusion criteria were primary, single-level MIS TLIFs. We excluded multilevel procedures and patients without preoperative PROMs. Pre- and postoperative PROMIS PF, VAS back, and VAS leg scores were recorded at 6 weeks, 12 weeks, 6 months, and 1 year. A Pearson correlation evaluated PROMIS PF association with VAS back and VAS leg scores. A Fisher z-test compared correlations. Linear regression evaluated PROMIS with VAS back and VAS leg scores.

Results:

Our cohort was comprised of 146 subjects. 40.4% were female and the average age of 51 years. VAS back demonstrated a stronger correlation than VAS leg with PROMIS PF at all timepoints. PROMIS PF scores were negatively associated with both VAS back and VAS leg at all timepoints. Fisher z-test revealed VAS back to have a stronger correlation with PROMIS PF (p = 0.025) than VAS leg.

Conclusion:

In the setting of MIS TLIF, physical function as evaluated by PROMIS PF, had a stronger correlation with VAS back than VAS leg at 6 months. This suggests that postoperative PROMIS PF scores may be more influenced by back pain than with leg pain.