Pre-operative manometry of the blind rectal pouch to predict post-operative potential for continence in anorectal malformation.

ABSTRACT

AIM: Despite technical advances in the surgical repair of anorectal malformation, many children suffer post-operative faecal incontinence. There are many ways to assess postoperative continence in these patients but there is no manometry-based method to assess and make predictions pre-operatively. In this pilot study an attempt was made to correlate the pre- and postoperative manometry and electromyography findings in order to use the pre-operative findings to predict the postoperative potential for continence. METHODS: Ten patients aged 12 to 54 months were subjected to pre-posterior sagittal anorectoplasty manometry by introducing the balloon catheter probe through the distal colostomy into the blind rectal pouch. Electromyography activity in the striated muscle complex was also studied by placing electromyography needles in the midline in the anal dimple. A second study was repeated after posterior sagittal anorectoplasty (PSARP), the probe was introduced into the rectum via the neo-anus and the electromyography needles were placed on either side of the neo-anus. A third study was done, similar to the second study, after colostomy closure along with Kelly's scoring. Results of the three studies were compared. RESULTS: Pre-posterior sagittal anorectoplasty rectal pouch pressures were in the range of 18.3-93.3 cm H2O and electromyographic activity was between 43.6 and 383.0 microv. Post-posterior sagittal anorectoplasty studies showed anal canal pressure in a similar range of 16.0-95.5 cm H2O and electromyographic activity between 57.0-340.7 microv. The post-colostomy closure anal canal pressures ranged from 22.7 to 99.1 cm H2O and electromyographic activity ranged from 65.7 to 335.7 microv. The Kelly's score ranged from 1-6. CONCLUSION: Since, the pre-and postoperative manometry findings are quite similar and they correlate well with the surgical outcome, it may be possible to predict such an outcome before PSARP. Also, the pressure profiles and EMG activity in post-operative assessments suggest intact neural pathways despite blind pouch mobilisation.