Lower extremity motor deficits are underappreciated in patient-reported outcome measures: Added value of objective outcome measures

Abstract

Objective: The patient-reported outcome measure (PROM)-based evaluation in lumbar degenerative disc disease (DDD) is today’s gold standard but has limitations. We studied the impact of lower extremity motor deficits (LEMDs) on PROMs and a new objective outcome measure. Methods: We evaluated patients with lumbar DDD from a prospective 2-center database. LEMDs were graded according to the British Medical Research Council (BMRC; 5 [nor-mal] –0 [no movement]). The PROM-based evaluation included pain (visual analogue scale), disability (Oswestry Disability Index [ODI] & Roland-Morris Disability Index [RMDI]), and health-related quality of life (HRQoL; Short-Form 12 physical component summary/men-tal component summary & EuroQol-5D index). Objective functional impairment (OFI) was determined as age-and sex-adjusted Timed-Up and Go (TUG) test value. Results: One hundred five of 375 patients (28. 0%) had a LEMD. Patients with LEMD had slightly higher disability (ODI: 52. 8 vs. 48. 2, p = 0. 025; RMDI: 12. 6 vs. 11. 3, p = 0. 034) but similar pain and HRQoL scores. OFI T-scores were significantly higher in patients with LEMD (144. 2 vs. 124. 3, p = 0. 006). When comparing patients with high-(BMRC 0–2) vs. low-grade LEMD (BMRC 3–4), no difference was evident for the PROM-based evaluation (all p > 0. 05) but patients with high-grade LEMD had markedly higher OFI T-scores (280. 9 vs. 136. 0, p = 0. 001). Patients with LEMD had longer TUG test times and OFI T-scores than matched controls without LEMDs. Conclusion: Our data suggest that PROMs fail to sufficiently account for LEMD-associated disability, which is common and oftentimes bothersome to patients. The objective functional evaluation with the TUG test appears to be more sensitive to LEMD-associated dis-ability. An objective functional evaluation of patients with LEMD appears reasonable.