The effects of antimuscarinic agents on rectal compliance in patients with supraconal spinal cord injury

Introduction Constipation affects up to 80% of spinal cord injury (SCI) patients and is cause of significant reduction of quality of life. Rectal compliance is determined by the rectal wall properties and by the supra-spinal modulation of the thoracic sympathetic and para-sympathetic lumbosacral efferents; it is increased in SCI patients with injury level above T5. Often this patient group has associated bladder dysfunction, and requires antimuscarinic agents (Tolterodine or Solifenacin), which are known to cause constipation. The authors aimed to assess the physiological effect of antimuscarinic agents on the anorectal function of patients with SCI above T5. Methods The authors prospectively collected data from 17 SCI patients (11 males, mean age 41, mean disease duration 13 months) attending a neuro-gastroenterology clinic at a tertiary centre. All had an established SCI above T5, and 11 had a complete injury. Anal manometry, assessment of rectoanal inhibitory reflex (RAIR) and rectal compliance were measured at baseline, and after antimuscarinic treatment was started (mean follow-up 12 weeks). Results Anal sphincter function parameters of squeeze and cough pressure were unchanged after antimuscarinic treatment (pre vs post 123±40 vs 122±36 p=0.827; 88±24 vs 87±26 p=0.859 respectively). However, resting anal pressure and rectal compliance were significantly raised after antimuscarinic treatment (82±18 vs 88±16 p=0.058; 19.2±5.0 vs 24.2±4.1 p