Outcome at three to five years of primary closure of perianal and pilonidal abscess. A randomised, double-blind clinical trial with a complete three-year followup of one compared with four days' treatment with ampicillin and metronidazole.

OBJECTIVE

To evaluate the long term results after primary closure of perianal abscess and pilonidal sinus.

DESIGN

Follow up by questionnaire and study of casenotes.

SETTING

University hospital and district hospital.

SUBJECTS

88 Patients who had previously been in a prospective random control trial of two regimens of antibiotic treatment (ampicillin and metronidazole for one compared with four days) before incision, curettage, and primary closure of perianal abscess or pilonidal sinus.

MAIN OUTCOME MEASURES

Recurrence rate and outcome.

RESULTS

32 Patients had perianal abscesses of which 31 (97%) healed primarily (95% confidence interval [CI] 84 to 100%) with 4 recurrences (13%, 95% CI 2 to 24%). 56 Patients had pilonidal sinuses or abscesses of which 46 (82%) healed primarily (95% CI 70 to 91%) with 14 recurrences (30%, 95% CI 16 to 40%). There were no significant differences between the two antibiotic regimens. The mean followup was 53 months. Two patients had died, both had had perianal abscesses. Pilonidal sinuses tended to recur during the first year, whereas pilonidal abscesses recurred after a lapse of two years or more. Half the patients who had had previous operations for the same complications, compared with a third who were being operated on for the first time.

CONCLUSIONS

A one day course of ampicillin and metronidazole is not associated with any more complications than a four day course. Perianal abscesses respond well to primary closure, but management of pilonidal abscesses and sinuses is more difficult.