Physiotherapy with integrated virtual reality for patients with severe chronic low back pain: cluster-randomized controlled trial (VARIETY)

INTRODUCTION: Chronic low back pain (CLBP) is a leading cause of disability worldwide. Physiotherapy is a common treatment, but its effect on physical functioning is generally modest, particularly for patients with severe complaints (i.e., high levels of disability and pain). Virtual Reality (VR) may complement physiotherapy, yet evidence for its effectiveness remains limited. The aim of this study was to assess the effectiveness and feasibility of a VR intervention integrated within physiotherapy for people with severe CLBP. METHODS: A cluster-RCT across Dutch physiotherapy practices was conducted. Patients in the control group received 12 weeks of usual care following physiotherapy guidelines. Patients in the intervention group received similar usual care, enhanced with integrated, home-based VR consisting of pain education, exercise therapy, and relaxation modules. The primary outcome was physical functioning at three months. Secondary outcomes included feasibility, pain intensity, and catastrophizing. Analyses were conducted using linear mixed-effect models accounting for clustering by physiotherapy practice. RESULTS: Twenty-five patients participated in the intervention group and seven in the VARIETY control group, instead of the planned sample size of 120 participants. Due to poor recruitment (n = 7), we supplemented the VARIETY control group with 18 historical controls from two comparable trials (total control n = 25), effectiveness analyses are therefore exploratory. Between-group differences were neither statistically significant nor clinically relevant for all outcome measures, compared to the VARIETY control group (e.g., ODI mean difference at three months: -4.80, 95%CI: -17.78;8.18), or the total control group (-8.80, 95%CI: -20.17;2.57). The intervention group showed greater improvements from baseline in physical functioning (42%), compared to the VARIETY control group (26%). The intervention was considered feasible and safe to use in practice. DISCUSSION: This study found limited support for the use of VR as an adjunct to physiotherapy for people with severe CLBP. Given the use of external control data and the limited sample size, the effectiveness results should be interpreted cautiously. Further well-powered trials should reconsider study procedures to optimize patient recruitment and corroborate VR's clinical effectiveness in physiotherapy. TRIAL REGISTRATION: The study was registered with ClinicalTrials.gov on 2022-12-02 (reference number: NCT05701891).