Objectives: The aim of this pilot study was to estimate the sample size for a large pragmatic study of the comparative effectiveness of electroacupuncture (EA) for low back pain (LBP) after back surgery.
Design: A randomised, active-controlled, assessor-blinded trial.
Participants: Patients with recurrent or persistent LBP, defined as a Visual Analogue Scale (VAS) score of ≥50 mm, with or without leg pain after back surgery.
Interventions: Patients were randomised to an EA plus usual care (UC) group or to a UC alone group at a 1:1 ratio. Patients assigned to each group received UC, including drug therapy, physical therapy and back pain education, twice a week for 4 weeks; those assigned to the EA plus UC group additionally received EA.
Outcome measures: The primary outcome was severity of LBP as measured by VAS. Secondary outcomes included back pain-related disability, assessed using the Oswestry Disability Index (ODI) and quality of life, assessed using the EuroQol Five Dimensions (EQ-5D) questionnaire. Statistical analysis was performed using paired and independent t-tests. A p value of <0.05 was considered statistically significant.
Results: Thirty-nine patients were allocated to receive EA plus UC (n=18) or UC alone (n=21). There was no statistically significant difference in VAS or EQ-5D scores between the two groups, but there was a significant decrease in ODI scores (p=0.0081). Using G*Power, it was calculated that 40 participants per group would be needed for a future trial according to VAS scores. Considering for a 25% dropout rate, 108 participants (54 per group) would be needed.
Conclusions: A future trial addressing the risk of bias and including the estimated sample size would allow for better clinical assessment of the benefits of EA plus UC in treatment of patients with non-acute pain after back surgery.
Trial registration number: NCT01966250; Results.
Keywords: back surgery; electroacupuncture; integrative medicine; low back pain; pilot trial; postoperative pain.
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