Neglecting Bone Health: A Critical Gap in Management of Muscle Spasticity with Botulinum Toxin in Spinal Cord Injury

Abstract

Neuromuscular inhibitors have been quickly advanced from being used only for aesthetic purposes to being used as a treatment for musculoskeletal pain and muscle spasticity. This phenomenon stems from the diminished force exerted by muscles, which are essential for bone remodeling. In this context, it is hypothesized that botulinum toxin (BTX) might exert a direct influence on bone resorption. Although such treatments have the potential to provide patients with significant relief, bone loss occurring due to elective muscle paralysis has yet to be examined in clinical trials. The disuse model resulting from spinal cord injury, characterized by the absence of ground reaction and muscle forces, provides an ideal context for exploring the skeletal ramifications of intramuscular BTX injection. This approach enables an investigation into the intricate interplay between muscle and bone, encompassing the impact of spasticity on bone preservation, the potential positive and negative outcomes of BTX on bone metabolism, and the involvement of the autonomic nervous system in bone remodeling regulation. This paper presents a narrative review of research findings on the disturbance of the typical balance between muscles and bones caused by acute muscle paralysis from BTX, resulting in osteopenia and bone resorption.