A team from Rome, Italy, evaluated the effectiveness of higher doses of botulinum toxin to induce healing in patients with chronic anal fissures.
A total of 150 patients with posterior anal fissures were treated with botulinum toxin. This was injected in the internal anal sphincter, on each side of the anterior midline.
Subjects were randomized into two treatment groups, based on the number of units of botulinum toxin injected.
Patients in Group I were treated with 20 units of botulinum toxin and, if the fissure persisted, were retreated with 30 units.
Patients in Group II were treated with 30 units and retreated with 50 units, if the fissure persisted.
The two groups were comparable in age, gender distribution, duration of symptoms, resting pressure, and maximum voluntary pressure at anorectal manometry.
One month after the injection, examinations revealed complete healing in 55 patients (73%) from Group I and 65 patients (87%) from Group II.
Some 5 patients from Group II reported a mild incontinence of flatus that lasted 2 weeks after the treatment and disappeared spontaneously.
The researchers found that values of the resting anal pressure and the maximum voluntary pressure did not differ between the two groups.
At 2 months' evaluation, a healing scar was found in 67 patients (89%) from Group I, and 72 patients (96%) from Group II.
|Fissure healing at 2 months:|
Group I: 89%
Group II: 96%
A relapse of the fissure was observed in 6 patients (8%) from Group I who had a healing scar at 1 month. Two other patients never healed.
In addition, a persistent fissure was present in 3 patients from Group II who had no other symptoms.
Giuseppe Brisinda, of the Catholic University Hospital Agostino Gemelli, Rome, said on behalf of fellow authors, "Botulinum toxin injected into the internal anal sphincter is effective in managing anal fissures and avoiding permanent complications.
"All patients were treated with the active drug and healed after 1 or 2 successive treatments."
"The results also confirm that higher doses account for a higher success rate, with little increase in complications or side-effects, which is probably related to the diffusion of the toxin to the external sphincter," it was concluded.