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Objective:
To investigate the incidence of superficial fistula formation as a complication following an open internal sphicterotomy. Additional objectives include determining the average time to diagnosis of a superficial fistula and whether an abscess formation following an anal sphicterotomy increases the incidence of superficial fistula formation.
Design:
Retrospective cohort study
Setting:
Colorectal surgeons part of a private group in an urban environment, performed the sphincterotomies in the operating room.
Patients:
Two-hundred ninety-nine patients who underwent an open internal sphincterotomy by one of the colorectal surgeons from 2005-2012 were included.
Main Outcome Measures:
Most recent research to report superficial fistulas as a complication of anal sphincterotomies was performed over twelve years ago and reported an incidence of less than 3%. We believe this complication is higher.
Results:
Of the 299 patients, 37 developed a superficial fistula (12.4%). Of those 37 patients, 31 subsequently underwent a fistulotomy in the operating room, 5 were lost to follow-up, and 1 patient was treated non-operatively. The mean time to diagnosis of the fistula after sphincterotomy was 45.8 days. Of the 299 patients, 64 (21.4%) patients developed abscesses afterwards. Thirty-three of the 37 patients (89.2%, p=0.003) who formed a fistula had an abscess develop prior. Of those 25 were treated with antibiotics only, 5 were treated with antibiotics followed by incision and drainage, and 3 patients only had incision and drainage.
Conclusions:
We found our incidence to be much higher at 12.4% compared to reported statistics. We feel that fistula formation is an underreported complication of this surgery. It is, however, a significant complication following this operation because in the majority of cases, it requires surgical intervention in the operating room.