Association between acute pain trajectory and patient-reported outcomes at 6-months following lumbar surgery for patients with lumbar degenerative disease.

Purpose: To investigate the association between acute pain trajectory over one week and patient-reported outcomes (PRO) at 6-months following lumbar surgery in patients with lumbar degenerative disease (LDD).

Methods: Two hundred and fifty-five subjects with LDD who received surgical treatment at our hospital between April 2019 and March 2022. Acute pain trajectory was measured using a pain trajectory calculator to determine an approximate line using the linear least squares method based on pain intensity on postoperative days 1, 3, 5, and 7. The pain trajectory-slope, which represents the change in postoperative pain intensity of the calculated approximation line, was evaluated as the main exposure for the present study. The PRO was assessed using the Oswestry Disability Index (ODI) measured at 6 ± 1 months postoperatively. Poor PRO scores in this study were defined using a threshold of an ODI of 22% or greater, which represents the patient acceptable symptomatic state after lumbar spine surgery. Multivariable logistic regression analysis including covariates was performed to investigate the association between pain trajectory-slope and PRO at 6-months following lumbar surgery.

Results: In this study, 101 (39.6%) had poor PRO scores. Multivariable logistic regression analysis adjusted for covariates showed that pain trajectory-slope was associated with the poor PRO scores (odd ratios; 1.203, 95% confidence intervals; 1.130-1.288).

Conclusions: The results of this study show that acute pain trajectory is significantly associated with poor PRO scores 6-months after lumbar surgery. Patients with slower pain relief or worsening pain were associated with poor PRO scores.