Canine model for treatment of faecal incontinence using transposed and electrically stimulated sartorius muscle.

A neosphincter was successfully created around each end of a Thiry-Vella loop in five dogs using transposed sartorius muscle to study new treatments for faecal incontinence. One of these dynamic neosphincters in each dog was electrically trained for 8 weeks while the other served as a control. Muscle biopsies demonstrated an increase in type 1 fatigue-resistant fibres from a median of 49 (range 37-54) per cent before electrical stimulation to 78 (range 53-99) per cent 8 weeks later in the stimulated sartorius neosphincters (P < 0.05), whereas the percentage of type 1 fibres in control neosphincters increased only slightly. Retention times of saline increased from a median of 10 (range 5-50)s before to 340 (range 100-470)s after electrical stimulation (P < 0.05) but also increased in control neosphincters (to 370 (range 330-1200)s); this may indicate that electrical stimulation immediately increases acute retention times. It is concluded that construction of a neosphincter is technically feasible with preservation of muscle morphology and that stimulation induces morphological and functional changes towards the characteristics of the external anal sphincter.