Kinetic and kinematic effects of using a walker during the sit-to-stand transfer after lumbar spinal fusion: A cross-sectional, within-subjects study.

Abstract

High pain levels after lumbar spinal fusion surgery often alter sit-to-stand kinematics, including reducing forward trunk inclination. These adaptations can lead to long-term kinematic deviations and chronic pain. Interventions are needed to facilitate sit-to-stand kinematics resembling those of healthy individuals while minimizing post-surgical pain. This study compared the effects of using both hands on a walker during sit-to-stand to pushing up from the sitting surface on several kinetic and kinematic variables. Fifteen participants (mean age 52.3 ± 14.1 years), on average 10 days after lumbar spinal fusion, performed alternating sit-to-stand trials. Data were collected using 3D motion capture and force plates to analyze differences between the two hand placement conditions. Using a walker did not significantly reduce trunk-pelvis external flexion moment (mean difference = 4.1 Nm, P = .582) when modeling the trunk as a rigid segment, but reduced ground reaction forces (-312.1 N), promoted a less acute trunk-pelvis angle (+6.9°), and decreased hip flexion moment (-71.3 Nm; all P < .001). Contrary to common concerns, no walker tipping occurred during the 45 sit-to-stand trials. Using hands on a walker for sit-to-stand after recent lumbar spinal fusion appears safe for individuals with presumably intact cognition. The lack of reduction in trunk-pelvis external flexion moments may reflect adaptive movement patterns employed to complete the task when the trunk is unsupported. Lower hip moments and a less acute trunk-pelvis angle when using the walker may support early mobilization by reducing joint loading and motion demands, potentially lessening pain.