A Comparison of Scar Infiltration, Scar Deactivation, and Standard of Care for Treatment of Chronic, Postsurgical Pain After Cesarean Section in the Primary Setting: A Comparative Effectiveness Trial

Introduction: Chronic pain following Cesarean section significantly impacts quality of life. Postcesarean pain is often treated with pharmacologic therapies; however, there are no evidence-based guidelines available for refractory pain. The objective of this study is to determine if acupuncture and lidocaine scar infiltration improve pain. Methods: This 20-week randomized control trial took place at two Air Force Base outpatient primary care clinics. Sixty postpartum Department of Defense beneficiaries aged 18 years or older with abdominal and/or back pain following a low transverse cesarean section, at least 3 months prior, were enrolled. Participants were randomized into one of 3 groups: (1) acupuncture scar deactivation, (2) scar infiltration with lidocaine, and (3) physical therapy (PT). The outcome measures were scar quality, as measured by the Patient and Observer Scar Assessment Scale (POSAS) and pain, as measured by the Defense and Veterans Pain Rating Scale (DVPRS) pre- and posttreatment, and were analyzed with random effects regression. Results: After excluding individuals with missing data, 35 (58%) were analyzed for DVPRS and 51 (85%) were analyzed for POSAS measures. Participants had a mean age of 35 years, a BMI of 30 kg/m2, and 70% identified as White. DVPRS declined from baseline to the last visit in the PT, scar deactivation, and scar infiltration groups by −42.7%, −54.4%, and −63.6%, respectively. The POSAS measures also declined in the PT, scar deactivation, and scar infiltration groups (patient: −57.5%, −47.7%, and −38.9%; observer: −10.9%, −34.7%, and −24.2%). The acupuncture group showed a stronger decline in the POSAS observer measure as compared to PT (interaction β = −0.29, p = 0.0217), but no differences were observed for the POSAS patient measure or DVPRS. When examining responder rates, only the POSAS observer measure was significant for a 50% reduction in the outcome, but post hoc group comparisons did not reach statistical significance in Table 5. Conclusion: This study found an improvement in the DVPRS, patient-reported Patient and Observer Scar Assessment score, and observer-reported Patient and Observer Scar Assessment score across all treatment groups at 20 weeks compared to the initial baseline. Compared to PT, our results suggest that acupuncture was associated with a stronger improvement in the POSAS observer measure, but no other differences between treatment conditions were observed. PT is a well-established treatment modality but requires specialist training and frequent visits. Scar deactivation is an effective treatment but also requires specialist training. Scar infiltration with lidocaine is a procedure easily performed by most primary care physicians with limited cost. Patient-specific factors such as time availability and provider access may best guide treatment decisions for these patients. Trial Registration: ClinicalTrials.gov identifier: NCT03936309.