PROMIS Physical Function Score Strongly Correlates With Legacy Outcome Measures in Minimally Invasive Lumbar Microdiscectomy

Benjamin Khechen, BA; Brittany E. Haws, MD; Dil V. Patel, BS; Mundeep S. Bawa, BA; Islam M. Elboghdady, MD; Eric H. Lamoutte, BS; Sailee S. Karmarkar, BS; Kern Singh, MD


Spine. 2019;44(6):442-446. 

In This Article

Abstract and Introduction


Study Design: Retrospective cohort.

Objective: This study aims to determine the validity of the patient-reported outcomes measurement information system (PROMIS) physical function (PF) in minimally invasive lumbar discectomy (MIS LD) patients.

Summary of Background Data: PROMIS was designed to allow for assessment of clinical outcomes in fewer questions than previous outcome measures with the goal of reducing noncompliance associated with longer, time-consuming surveys. However, there exists a paucity of evidence regarding the efficacy of the PROMIS PF domain in patients undergoing MIS LD.

Methods: A surgical database of patients undergoing 1–3 level MIS LD was retrospectively reviewed. Postoperative changes in PROMIS PF scores were analyzed at 6-weeks, 12-weeks, and 6-months using paired Student t tests. PROMIS scores were compared to Oswestry disability index (ODI), visual analog scale (VAS) back, and VAS leg scores. Correlations were tested using Pearson correlation coefficient.

Results: Forty-one MIS LD patients were identified, reporting an average preoperative PROMIS PF score of 35.36 ± 7. Patients demonstrated significant improvement in ODI, VAS back, and VAS leg scores. Additionally, strong associations with PROMIS scores were observed for preoperative and postoperative ODI (r range: 0.5735–0.8543) and postoperative VAS back (r range: 0.5332–0.6522) and VAS leg pain (r range: 0.5257–0.6412).

Conclusion: Patients undergoing MIS LD demonstrated significant improvements in PROMIS PF, ODI, VAS back, and VAS leg pain postoperatively. Additionally, improvements in PROMIS physical function scores at each postoperative time point were determined to be significantly correlated with ODI, VAS back, and VAS leg pain. The results of the current study demonstrate PROMIS PF has strong utility as a postoperative outcome assessment tool.

Level of Evidence: 4


Patient-reported outcome (PRO) measures have recently gained increased attention in orthopedic research as an instrument for assessing postoperative clinical outcomes. The utility and validity of these PROs, collectively referred to as "legacy measures," have been demonstrated in multiple orthopedic studies.[1–4] Currently, the Oswestry disability index (ODI) and visual analogue scale (VAS) for back and leg pain are among the most commonly used PROs for lumbar spine surgery patients.[4] However, these legacy measures are not without limitations, including significant time consumption affecting compliance, floor and ceiling effects, and impreciseness at the extremes of function.[2] These limitations have been suspected to affect the ability to efficiently and accurately collect long-term data, due to the administrative burden and patient noncompliance.

In an effort to address the limitations of legacy measures, the National Institute of Health (NIH) developed the patient-reported outcomes measurement information system (PROMIS).[5] PROMIS utilizes computer-adaptive testing based on item response theory, which dynamically modifies subsequent questions based on previous answers selected. Thus, employing fewer questions while increasing precision, and potentially improving compliance with long-term data collection.

There have been few studies to date validating the use of PROMIS scores in comparison with legacy PROs in select lumbar spine populations.[1,3,6–10] However, to our knowledge, there have been no studies reporting on the efficacy of PROMIS in patients undergoing minimally invasive lumbar microdiscectomy (MIS LD). Therefore, the purpose of our study is to determine the validity and correlation of PROMIS to traditional legacy PRO measures in patients undergoing MIS LD.