Anorectal function in patients with complete spinal transection before and after sacral posterior rhizotomy

Area of Science:

• Neuroscience
• Gastroenterology
• Urology

Background:

• Complete spinal transection disrupts normal defecation mechanisms.
• Spinal stimulator implantation requires sacral posterior nerve root division.
• Understanding spinal reflexes is crucial for managing anorectal function in these patients.

Purpose of the Study:

• To investigate the role of spinal reflexes in anorectal function.
• To elucidate the mechanisms of defecation in patients with spinal cord transection.

Main Methods:

• Anorectal manometry and electromyography were used.
• 14 patients with supraconal spinal cord transection (C6-T12) were studied.
• Comparisons were made before and after sacral posterior rhizotomy, with 30 controls.

Main Results:

• Spinal transection abolished conscious external anal sphincter control.
• Rhizotomy eliminated reflex responses to rectal distention and intra-abdominal pressure.
• Giant rectal contractions were abolished by rhizotomy, but exaggerated sphincter relaxation persisted.

Conclusions:

• Exaggerated anorectal reflexes and loss of conscious control contribute to uncontrollable defecation.
• Posterior rhizotomy prevents reflex defecation and aids manual evacuation.
• External anal sphincter contraction during straining may impede fecal expulsion.