Correlation between pressure pain threshold and L4-5 supraspinous ligament biomechanics after cesarean delivery under spinal anesthesia

BackgroundLocalized low back pain is a frequent complaint after spinal anesthesia for cesarean delivery (CD).ObjectivesThis study aimed to examine the pressure pain threshold (PPT) and biomechanical properties (stiffness, elasticity, relaxation time, and creep) of the L4-5 supraspinous ligament at the spinal anesthesia needle insertion site in women who had CD. These measurements were compared with those from the controls who never had pregnancy or anesthesia, and correlations between the variables were explored.MethodsA retrospective cohort study involved 44 women, divided into two groups. Group A: 22 women experienced spinal anesthesia for CD, and Group B: 22 women represented the controls. L4-5 supraspinous ligament's PPT was measured using pressure algometry, and its biomechanical properties were assessed with the MyotonPRO device.ResultsSignificant differences were found in PPT between the two groups (P = 0.0001), but non-significant differences were observed in stiffness, elasticity, relaxation time, or creep (P = 0.318, 0.344, 0.241, and 0.227, respectively). There were also non-significant correlations between PPT and biomechanical properties.ConclusionWomen who experienced spinal anesthesia for CD showed increased tenderness and lower PPT at the L4-5 site, 6-12 weeks postpartum, with minor changes in supraspinous ligament biomechanics. The relationship between PPT and these properties was negligible.