Results of a policy of selective immediate fistulotomy for primary anal abscess.

A prospective study of a policy of selective immediate fistulotomy in the management of acute primary anal abscesses was performed. Eighty-nine patients (74%) underwent simple drainage only, as no internal openings were found during drainage of pus (group A). Thirty-one patients (26%) had drainage of pus and immediate fistulotomy (group B). Follow up for groups A and B occurred at a median of 122 weeks (104-136 weeks) and 121 weeks (104-136 weeks), respectively. No patient in group A had residual problems with anal continence whilst two patients (6.5%) from group B had minor anal incontinence following the initial procedure (p = 0.07). Ten patients from group A (11%) and four patients from group B (13%) developed recurrent anal sepsis. The overall rate of recurrent sepsis was 11.7%. In those patients who had incision and drainage alone, 90% of those who developed a recurrence and 71% of those who did not develop a recurrence grew gut-associated organisms from pus obtained during the initial drainage of the acute abscess, giving a positive predictive value for recurrence of 13.8% for a culture of gut-associated organisms. The positive predictive value for recurrent sepsis for both groups taken together for a culture of gut-associated organisms was 28.2%. Patients with acute primary anal abscess should be treated with simple drainage.