Obstetrics & Gynecology · Medical Literature
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.
Abstract
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. 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. 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. 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. ClinicalTrials.gov identifier: NCT03936309.
Clinical relevance
Chronic post-cesarean pain is a clinically underrecognized condition that significantly impairs quality of life in postpartum patients, yet no evidence-based guidelines exist for managing refractory cases beyond standard pharmacotherapy. This trial directly addresses that gap by comparing three accessible, non-opioid interventional strategies in a primary care setting, offering practical options for the large and growing population of cesarean-delivered patients. Given rising cesarean rates globally, identifying effective, accessible, and low-cost treatments is an urgent clinical priority for obstetricians and primary care physicians managing postpartum pain.
Key findings
1. Pain scores (DVPRS) declined from baseline to final visit across all three treatment arms over 20 weeks: physical therapy (PT) -42.7%, acupuncture scar deactivation -54.4%, and lidocaine scar infiltration -63.6%, though no statistically significant between-group differences were detected for DVPRS. 2. Patient-reported scar quality (POSAS patient subscale) improved in all groups: PT -57.5%, scar deactivation -47.7%, and scar infiltration -38.9%, with no statistically significant differences between groups. 3. Observer-reported scar quality (POSAS observer subscale) improved across groups: PT -10.9%, scar deactivation -34.7%, and scar infiltration -24.2%; acupuncture scar deactivation demonstrated a statistically significantly stronger improvement compared to PT (interaction β = -0.29, p = 0.0217). 4. Responder analysis (≥50% reduction in outcome) showed significance only for the POSAS observer measure across groups, but post hoc pairwise comparisons did not reach statistical significance. 5. The study enrolled 60 Department of Defense beneficiaries (mean age 35 years, mean BMI 30 kg/m², 70% White), with 58% (n = 35) analyzed for DVPRS and 85% (n = 51) analyzed for POSAS outcomes, representing a notable attrition limitation. 6. No statistically significant between-group differences were observed for pain (DVPRS) or patient-reported scar quality (POSAS patient subscale) at any time point, suggesting comparable analgesic efficacy across all three modalities.
Practice implications
Primary care physicians and obstetricians can consider lidocaine scar infiltration as a first-line procedural option for refractory post-cesarean pain, given its comparable effectiveness to PT and acupuncture, low cost, and feasibility for most primary care providers without specialist referral. Acupuncture scar deactivation may be preferentially selected when objective scar quality improvement is a primary treatment goal, as it demonstrated superior observer-rated scar outcomes versus PT (p = 0.0217), though patient-perceived benefit was similar across modalities. Treatment selection should be individualized based on patient access, provider availability, and time constraints, as all three modalities produced clinically meaningful reductions in pain and scar scores over the 20-week treatment course.