Special Poster Session 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

INTRODUCTION

Patient-Reported Outcomes Measurement Information System (PROMIS) tools offer alternatives to legacy outcome measures. The National Institutes of Health Task Force on Research Standards for Chronic Low Back Pain has encouraged use of PROMIS domains. Recent study findings suggest PROMIS tools are appropriate for long-term outcome assessment in spine surgery populations. However, the dissemination of PROMIS into clinical practice has been limited and more work showing longitudinal congruence between PROMIS and spine legacy measures may increase adoption of PROMIS measures to assess patient reported outcomes. The purpose was to compare the trajectories of patient reported outcomes (PROs) as reported by PROMIS to other legacy measures of disability and pain over time. To better understand the timelines for healing in patients with lumbar procedures, we reported outcome trajectories of laminectomy alone vs. with fusion.

METHODS

A secondary analysis was conducted from a randomized controlled trial comparing postoperative cognitive-behavioral based physical therapy (n=124) to an education program (n=124). 84 (34%) patients had decompression alone and 164 (66%) had decompression with fusion. Outcome measures included PROMIS CAT Physical Function (PF) and Pain Interference (PI); Oswestry Disability Index (ODI); Numeric Rating Scale leg (NRS-LP) and back pain (NRS-BP), Brief Pain Inventory (BPI). Participants completed PROs preoperatively, 6 weeks, 6-, 12-, and 24-months after surgery. Mean scores were plotted at each time point for all outcomes and patients were stratified by fusion status. T-scores were reported for PROMIS measures which are standardized with a mean of 50 (SD=10). Pearson's correlations across measures were done within each timepoint.

RESULTS

The pattern of trajectories for all outcomes showed significant improvements from preop to 6-weeks (p<0.001) and from 6-weeks to 6-months (p<0.001) with very little change between 6 and 24 months postoperative. Between preoperative and 24-months, PROMIS PF T-scores for both fusion (baseline: 33±6 to 24mo: 43±7) and decompression (baseline: 34±6 to 24mo:43±7) groups improved from scores indicating moderate to mild problem (Figure 1). For PROMIS PI T-scores, fusion (baseline: 66±6 to 24mo: 53±7) and decompression (baseline: 66±7 to 24mo: 53±8) patients both improved from scores indicating moderate problems to normal levels. For both PROMIS outcomes, the fusion group showed less improvement at 6 weeks, but both groups had similar scores by 6 months after surgery and remained similar at 12 and 24 months. ODI (Figure 1) and pain score trajectories showed a similar pattern of responses over time. Correlations within timepoint ranged from r=-0.84 to -0.67 for PF and ODI and r=0.69-0.78 for PI with BPI. Back and leg pain correlations with PI were weaker (r=0.30- 0.70). All correlations were significant (p<0.001).

DISCUSSION

PROMIS PF and PI showed similar 24-month trajectories to ODI, NRS pain measures, and BPI following lumbar spine surgery with most change occurring in the first 6 months. Fusion patients tend to have slightly worse scores than decompression at 6 weeks but both groups have similar scores by 6 months postoperatively and remain similar through 24 months. These results support the use of PROMIS measures to assess outcomes in a degenerative spine population.