Efficacy and Mechanism of Moxibustion Combined with Conventional Rehabilitation Therapy for Postpartum Pelvic Girdle Pain with Kidney-Yang Deficiency Syndrome and Insufficient Core Stability

Primary symptoms: soreness and weakness of the waist and knees, decreased libido, aversion to cold and cold limbs. Secondary symptoms: mental lethargy, frequent urination at night, lower limb edema, shortness of breath on exertion, dry and brittle hair with loose teeth. Pale tongue with white coating; deep, slow pulse, weak at the chi position.

A diagnosis can be made when 2 primary symptoms and 2 secondary symptoms are present. Syndrome quantification: primary symptoms are scored as 9, 6, 3, and 0 points for severe, moderate, mild, and absent, respectively; secondary symptoms are scored as 3, 2, 1, and 0 points; tongue and pulse manifestations serve only as a basis for syndrome differentiation.2.2.3 Determination of insufficient core stabilityA pressure biofeedback unit (uniformly set at 40 mmHg and placed at the subject's L4–L5 level) was used in combination with the Sahrmann core stability test [16–17].

Lower-limb movement tasks of progressively increasing difficulty (levels 1–5) were performed in sequence. Subjects who failed to meet the level-2 criterion (both lower limbs in hip and knee flexion, with one foot sliding along the bed surface and a pressure deviation ≥ 10 mmHg) were determined to have insufficient core stability.2.2.4 Inclusion, exclusion, and withdrawal criteriaInclusion criteria: ① Meeting the above PGP diagnostic criteria, kidney yang deficiency syndrome differentiation, and insufficient core stability criteria; ② Aged 20–40 years, 6 months to 5 years postpartum; ③ VAS score of 3–6 cm at enrollment; ④ Voluntary participation with signed informed consent.Exclusion criteria: ① Low back pain located between the lower costal margin and the fifth lumbar vertebra; ② Pregnancy, acute pelvic inflammatory phase, or history of pelvic surgery within the past 3 months; ③ Unresolved lochia or menstruation, or poor perineal wound healing; ④ Previous history of lumbar spine, pelvic girdle, or hip joint surgery; ⑤ Mental disorders, obvious physical defects, major diseases, or cognitive impairment.Withdrawal criteria: ① Erroneously enrolled subjects who did not meet the inclusion criteria; ② Incomplete clinical data affecting safety assessment; ③ Failure to undergo assessment as required; ④ Concurrent receipt of other interventions such as medication during the study period.2.3 Intervention Protocol2.3.1 Control group (conventional rehabilitation therapy)① Pelvic symmetry adjustment: According to the orthopedic manual therapy assessment standards of the American Physical Therapy Association [18], bony landmarks including the anterior superior iliac spine, posterior superior iliac spine, and the highest point of the iliac crest were palpated to assess pelvic symmetry in three planes, and corresponding manual adjustments were performed, 5–10 min per session. ② Exercise therapy: Based on the principles of core strength training [19], a movement training library was established, including core muscle group activation and basic training (transversus abdominis, pelvic floor muscles, multifidus, internal and external obliques, gluteal muscles, etc.) and stretching training for tense muscle groups, 30–40 min per session.

Both components were performed twice weekly for 6 consecutive weeks.2.3.2 Experimental group (moxibustion combined with conventional rehabilitation therapy)Moxibustion was added on the basis of the control group interventions. Acupoint selection: Dazhui (GV14), Mingmen (GV4), bilateral Shenshu (BL23), Guanyuan (CV4), Zusanli (ST36), and Xuehai (SP10), with locations referenced to the national standard GB/T 12346-2006 Nomenclature and Location of Acupoints.

Procedure: A uniformly sized single-hole moxa box was used for warm moxibustion. The moxa section was approximately 2 cm long, with both ends flattened and compacted; the moxa box was fixed onto the acupoint skin with adhesive tape, and the lit moxa section was inserted onto the metal needle of the moxa box. First, the subject assumed a prone position for moxibustion at Dazhui, Mingmen, and Shenshu, then a supine position for moxibustion at Guanyuan, Zusanli, and Xuehai.

Moxibustion was performed until the skin became slightly red without burning pain, 20 min per acupoint. Conventional rehabilitation therapy was performed after moxibustion, following the same protocol as the control group. Twice weekly for 6 consecutive weeks.2.4 Outcome Measures2.4.1 Primary measureTime to onset of effect.

Definition of the onset event: a 50% reduction in VAS score from baseline, or a syndrome efficacy index reaching 30%–50%, was determined as a positive event (onset of effect). Assessed once weekly during the intervention period.2.4.2 Secondary measures① VAS score (0–10 cm); ② Pelvic Girdle Questionnaire (PGQ) score [20], comprising 20 activity items and 5 symptom items, assessing functional limitations caused by pelvic girdle pain; ③ TCM syndrome score and syndrome efficacy index [21].

Syndrome efficacy index = [(pre-treatment score − post-treatment score) / pre-treatment score] × 100%. An efficacy index ≥ 80% indicates clinical control, 50%–80% marked improvement, 30%–50% improvement, and < 30% no effect. Assessment time points: before treatment, weekly during the intervention, and 6 weeks after intervention.2.4.3 Mechanistic measures① Musculoskeletal ultrasound elastography (SWE): A musculoskeletal ultrasound system (Siemens Sequoia Silver, Germany) was used to measure the elastic modulus (kPa) and shear wave velocity (m/s) of the diaphragm, bilateral rectus abdominis, bilateral multifidus, external oblique, internal oblique, and transversus abdominis at rest and under functional states [maximal inspiration, maximal expiration, maximal contraction, and during Active Straight Leg Raise (ASLR) activation (Active, A) / non-activation (None active, NA)]. ② Muscle strength: The DIERS myoline multifunctional body strength testing system was used to evaluate the muscle strength (N) of trunk flexion/extension, lateral flexion, and rotation, as well as hip flexion/extension, abduction/adduction, and knee flexion/extension muscle groups, comparing left and right sides. ③ Endurance: The Bourban trunk endurance test [22] was used to record the maintenance time (s) of ventral (flexion), lateral (lateral flexion), and dorsal (extension) movements.

Assessment time points: before intervention and 6 weeks after intervention.2.4.4 Follow-up measuresFollow-up was conducted 1 month after the end of intervention, assessing VAS, PGQ, and TCM syndrome scores.2.4.5 Safety measuresOccurrence of adverse events / adverse reactions during the intervention period.2.5 Statistical

Methods

Statistical analysis was performed using SPSS 25.0 software. Measurement data conforming to a normal distribution are expressed as mean ± standard deviation (x̄ ± s); intergroup comparisons were performed using the two independent samples t-test. Non-normally distributed data are expressed as median (interquartile range) [M (P25, P75)] and analyzed using the two independent samples rank-sum test.

Count data were analyzed using the chi-square test. Time to onset of effect was analyzed using the Kaplan–Meier method to plot survival curves, with intergroup comparison by the Log-Rank test. The test level was α = 0.05 (two-sided), and P < 0.05 was considered statistically significant.