Botulinum toxin injection for chronic anal fissure: a prospective controlled study with long follow-up

Botulinum toxin is an effective therapeutic option for chronic anal fissure. However, there is no evidence about treatment standardization and long-term follow-up. We aimed to evaluate the short- and long-term efficacy and safety of botulinum toxin compared to close lateral internal sphincterotomy, with a 5-year follow-up.

This was a prospective, controlled, single-center study conducted at University Hospital of Ferrara, Ferrara, Italy. The primary outcome was fissure healing at 1 month. Secondary outcomes were Quality-of-Life (QoL) at 1 month and after 5 years, and fissure recurrence at 6 months and 5 years.

A total of 59 patients received botulinum toxin injection (Botox), and 32 underwent lateral internal sphincterotomy. At 1 month after treatments, postoperative pain decreased faster and significantly more in the Botox group (30 vs. 60 mm; P<0.001); fissure re-epithelization was observed in 59.4% of the surgical group compared to 25.4% of Botox (P=0.0001). Anal sphincter pressures decreased more in surgical group (P=0.044), although severe anal incontinence was present only in this subset (6.2%; P=0.041). Compared to surgery, patients who received Botox had higher satisfaction rates (P<0.001). Fissure recurrence at 6 months was more common in Botox than surgical group (16.9% vs. 3.2%, respectively; P=0.053). The overall healing rate improved in all patients and persisted at 12 months and 5 years in both groups with overall high patient satisfaction despite mild anal incontinence in 21.8% in the surgery group (P<0.05).

Botox, rather than surgery, should be considered the first-line treatment for chronic anal fissure.