Colonic dysfunction in patients with thoracic spinal cord injury

Abstract

Severe constipation is a debilitating concomitant of complete traumatic thoracic spinal cord injury. In order to investigate the pathophysiology of this symptom, we studied colonic compliance, as well as motor and myoelectrical activity, in the fasting and postprandial states and after neostigmine stimulation in 9 patients with clinically and electrophysiologically documented complete thoracic spinal cord injury. Electrophysiologic studies, including nerve conduction velocities, cortical and spinal somatosensory-evoked responses, and bulbocavernosus reflex responses, as well as urinary bladder cystometry, documented normal peripheral somatosensory function, integrity of the distal spinal cord, conus medullaris and cauda equina, and interruption of the somatosensory and descending spinal pathways proximal to the cauda equina. These 9 patients with spinal cord injury demonstrated a decrease in colonic compliance compared with a control group (p less than 0.01). They failed to demonstrate the postprandial increase in colonic motor and myoelectrical activity observed in a control group (p less than 0.01), but did respond to neostigmine with an increase in both motor and myoelectrical activity (p less than 0.02), suggesting an intact myogenic component. In these patients, decreased colonic compliance and absent postprandial colonic motor and myoelectrical activity may be mediated by ablation of outflow from higher centers to the lower spinal cord and may be correlates of visceral neuropathy and severe constipation.