OBJECTIVETo establish and evaluate a rabbit model of fecal incontinence.

METHODSTwelve normal adult male New Zealand rabbits were randomly divided into experimental group and control group. The nerve innervating the external anal sphincter, namely the fourth sacral nerve, was functionally located and selectively damaged with local injection of 50 g/L ropivacaine in the experimental group, and normal saline injection was administered in the control group. The changes in the resting anal pressure was examined before and after the surgery, and the electromyogram (EMG) of the external anal sphincter was recorded for comparison with the pathological changes of the fourth sacral nerve.

RESULTSCompared with the control group, the experimental group exhibited significantly decreased resting anal pressure after the surgery. The EMG of the experimental group showed abnormal nerve conduction velocity of the fourth sacral nerve, suggesting successful nerve block. Transmission electron microscope revealed irreversible pathological changes in the ultrastructure of the axons of the fourth sacral nerve.

CONCLUSIONThis method allows successful establishment of fecal incontinence in rabbits, which facilitates further in vivo study of artificial sphincters for treatment of anal incontinence.