This meta-analysis of randomized clinical trials (RCTs) was aimed at evaluating the effects of massage therapy in the treatment of postoperative pain.
Three databases (PubMed, Embase, and Cochrane Central Register of Controlled Trials) were searched for RCTs published from database inception through January 26, 2021. The primary outcome was pain relief. The quality of RCTs was appraised with the Cochrane Collaboration risk of bias tool. The random-effect model was used to calculate the effect sizes and standardized mean difference (SMD) with 95% confidential intervals (CIs) as a summary effect. The heterogeneity test was conducted through I2. Subgroup and sensitivity analyses were used to explore the source of heterogeneity. Possible publication bias was assessed using visual inspection of funnel plot asymmetry.
The analysis included 33 RCTs and showed that MT is effective in reducing postoperative pain (SMD, -1.32; 95% CI, −2.01 to −0.63; p = 0.0002; I2 = 98.67%). A similarly positive effect was found for both short (immediate assessment) and long terms (assessment performed 4 to 6 weeks after the MT). Neither the duration per session nor the dose had a significant impact on the effect of MT, and there was no difference in the effects of different MT types. In addition, MT seemed to be more effective for adults. Furthermore, MT had better analgesic effects on cesarean section and heart surgery than orthopedic surgery.
The authors concluded that MT may be effective for postoperative pain relief. We also found a high level of heterogeneity among existing studies, most of which were compromised in the methodological quality. Thus, more high-quality RCTs with a low risk of bias, longer follow-up, and a sufficient sample size are needed to demonstrate the true usefulness of MT.
The authors discuss that publication bias might be possible due to the exclusion of all studies not published in English. Additionally, the included RCTs were extremely heterogeneous. None of the included studies was double-blind (which is, of course, not easy to do for MT). There was evidence of publication bias in the included data. In addition, there is no uniform evaluation standard for the operation level of massage practitioners, which may lead to research implementation bias.
Patients who have just had an operation and are in pain are usually thankful for the attention provided by carers. It might thus not matter whether it is provided by a massage or other therapist. The question is: does it matter? For the patient, it probably doesn’t; However, for making progress, it does, in my view.
In the end, we have to realize that, with clinical trials of certain treatments, scientific rigor can reach its limits. It is not possible to conduct double-blind, placebo-controlled studies of MT. Thus we can only conclude that, for some indications, massage seems to be helpful (and almost free of adverse effects).
This is also the conclusion that has been drawn long ago in some countries. In Germany, for instance, where I trained and practiced in my younger years, Swedish massage therapy has always been an accepted, conventional form of treatment (while exotic or alternative versions of massage therapy had no place in routine care). And in Vienna where I was chair of rehab medicine I employed about 8 massage therapists in my department.