Early functional training is not superior to routine rehabilitation in improving walking distance and multifidus atrophy after lumbar fusion: a randomized controlled trial with 6-month follow-up.

Purpose: To investigate the effects of early functional training within a 12-week rehabilitation program on walking distance and lumbar multifidus atrophy following lumbar fusion surgery.

Methods: A total of 52 patients who underwent lumbar fusion surgery were randomly assigned to either the early functional training group (n = 26) or the routine rehabilitation group (n = 26). The early functional training group (FT group) began a progressive functional training program within the first 12 weeks post-surgery, while the routine rehabilitation group (RH group) started the same training program 12 weeks after surgery. The primary outcome was the walking distance, measured as the 6-minute walk distance (6MWD) at the 3-month, and 6-month follow-up. Secondary outcomes included the cross-sectional area (CSA) of the multifidus muscles, the Visual Analogue Scale (VAS) score, the Oswestry Disability Index (ODI) score, the Short Form 36 Health Survey (SF-36) subscales, including the Physical Component Summary (PCS) and Mental Component Summary (MCS), and the incidence of adverse events. The primary aim was evaluated using a 2-way mixed-model analysis of covariance (ANCOVA), with treatment group as the between-subjects factor and time as the within-subjects factor, after adjusting for baseline measures.

Results: Among the total patients, 38 (73.1%) left with at least one follow-up result, and 29 (55.8%) completed all treatment sessions and obtained an MRI assessment. The mixed-model ANCOVA revealed a significant group-by-time interaction for the 6MWD (F = 6.214, p = 0.003). Patients in the FT group demonstrated superior 6MWD compared to the GH group at 3 months (95% CI: 32.51 to 101.88, p < 0.001). No significant differences were found between the two groups at the 6-month follow-up (95% CI: -15.34 to 54.03, p = 0.271). Regarding secondary outcomes, no significant group-by-time effects were found for ODI (F = 1.221, p = 0.299), PCS (F = 0.166, p = 0.847), or MCS (F = 0.282, p = 0.755). No significant differences were found in the CSA of multifidus muscles between the groups. Nine patients (17.3%) experienced adverse events.

Conclusion: Early functional training after lumbar fusion was not superior to routine rehabilitation in improving walking distance, multifidus atrophy, pain, physical function, and quality of life during the 6-month follow-up. Trial registration number (TRN): ChiCTR2300068296.