Diastasis of rectus abdominis muscles in low back pain patients.

BACKGROUND: Abdominal muscles are important spinal stabilizers and its poor coordination, as seen in diastasis of rectus abdominis (DRA), may contribute to chronic low back pain (LBP). However, this has not yet been studied directly. OBJECTIVES: To conduct a pilot study to examine the association between DRA and LBP. METHODS: Using a digital caliper, standard clinical DRA measurement was performed in 55 participants with and 54 without chronic LBP. RESULTS: Participants were on average 55 years old, 69 (63%) were women. Among the 16 participants with DRA, 11 (69%) had chronic LBP; among the 93 participants without DRA, 44 (47%) had LBP. Among men, 7 of 9 (77%) with DRA had LBP and 14 of 31 (45%) without DRA had LBP. Among women, 4 of 7 (57%) with DRA had LBP and 30 of 62 (48%) without DRA had LBP. BMI was the strongest correlate of DRA and may explain the relation between DRA and chronic LBP. CONCLUSIONS: DRA and LBP may be interrelated, especially among men. This may be a function of greater BMI in individuals with chronic LBP. Understanding the association between DRA, LBP, and BMI may have important implications for treatment of LBP and for intervention.

MRI-based registration of pelvic alignment affected by altered pelvic floor muscle characteristics.

BACKGROUND: Pelvic floor muscles have potential to influence relative pelvic alignment. Side asymmetry in pelvic floor muscle tension is claimed to induce pelvic malalignment. However, its nature and amplitude are not clear. There is a need for non-invasive and reliable assessment method. An intervention experiment of unilateral pelvic floor muscle activation on healthy females was performed using image data for intra-subject comparison of normal and altered configuration of bony pelvis. METHODS: Sequent magnetic resonance imaging of 14 females in supine position was performed with 1.5 T static body coil in coronal orientation. The intervention, surface functional electrostimulation, was applied to activate pelvic floor muscles on the right side. Spatial coordinates of 23 pelvic landmarks were localized in each subject and registered by specially designed magnetic resonance image data processing tool (MPT2006), where individual error calculation; data registration, analysis and 3D visualization were interfaced. FINDINGS: The effect of intervention was large (Cohen's d=1.34). We found significant differences in quantity (P<0.01) and quality (P=0.02) of normal and induced pelvic displacements. After pelvic floor muscle activation on the right side, pelvic structures shifted most frequently to the right side in ventro-caudal direction. The right femoral head, the right innominate and the coccyx showed the largest displacements. INTERPRETATION: The consequences arising from the capacity of pelvic floor muscles to displace pelvic bony structures are important to consider not only in management of malalignment syndrome but also in treatment of incontinence. The study has demonstrated benefits associated with processing of magnetic resonance image data within pelvic region with high localization and registration reliability.