Botulinum Toxin and Hemorrhoids

Excerpt

To the Editor—We read with interest the article on the effectiveness of injection of botulinum neurotoxin (BT) after hemorrhoidectomy to reduce postoperative pain and to improve wound healing by Dr. Patti and coworkers.1Although the BT role in reducing pain after hemorrhoidectomy had been previously assessed by Dr. Davies in a double-blind study on 50 patients undergoing Morgan hemorrhoidectomy assigned to an injection of 20 BT units or normal saline into the internal anal sphincter (IAS), in this protocol the patients had been tested out without anorectal manometry and just for the first postoperative week. However, the BT subjects had significantly less pain toward the end of the first week after surgery.2Subsequently, Dr. Patti and coworkers,1 in a prospective, double-blind trial, randomized 30 patients with hemorrhoids of third-degree and fourth-degree to an injection of 0.4 ml of solution containing 20 botulinum toxin units (Botox®, Allergan, Irvine, CA) or saline solution, performed on each side of the anterior anal midline. At 5th and 30th postoperative days, both resting and defecatory anal pain and resting anal pressures, detected by anorectal manometry, were significantly lower than before treatment in the BT group, whereas they increased in the placebo arm.Pain after hemorrhoidectomy is multifactorial and dependent on individual pain tolerance, anesthesia, postoperative analgesia, and surgical technique. IAS spasm is believed to play an important role. Reduction in IAS spasm is the presumed mechanism of action of the toxin. Moreover, Dr. Patti and colleagues evaluated the time of healing of the perineal wounds, observing that it was shorter in the BT group than in the placebo block of patients (23.8 ± 4.1 days vs. 31.3 ± 5.5 days).Wound healing induced by BT injection could be attributed to the decrement of anal pressure, which could increase the mucosal blood flow improving the blood supply of the area and the formation of the scar tissue. Moreover, BT does not affect nonadrenergic noncholinergic innervations, which are mediated by nitric oxide (NO), which improves mucosal blood flow and mucosal protection.3BT diffusion in the tissues is a dose-dependent phenomenon. Histochemical staining of acetylcholinesterase has suggested that higher doses produce a biologic effect throughout the entire muscle, whereas smaller doses produce a gradient down the length of the muscle studied. Thus, performing the BT injection in four sites (1 on the anterior midline, 1 on the posterior midline, and 2 lateral) is possible to have a more homogeneous distribution of the BT through the entire anal sphincter.Furthermore, in recent studies, we have shown that by use of 30 Botox® units instead of 20 units, a better result can be obtained regarding anal resting pressure (decrease of anal resting pressure: from 30 percent after 20 units to 35 percent after 30 units at 2-month follow-up) and wound healing rate (from 89 percent after 20 units to 96 percent after 30 units 2 months after the injection).4In addition, in our clinical trials we constantly observed a decrement in anal resting pressure and an increase of healing rate, in patients with anal fissure treated with BT, between one and two months follow-up. Thus, performing the BT injection some days before the operation instead of after the hemorrhoidectomy could optimize the effect of BT treatment both on anal pain and wound healing.Considering the side effects of the procedure, the authors surprisingly reported a considerable number of patients with anal incontinence: nine patients, five in the placebo arm and four in BT group. Nevertheless, in every case it was mild incontinence time limited. It would be interesting to discuss with the authors whether there were some factors linked to the patients or to the procedure that influenced the outcome of the treatment. In conclusion, we confirm that BT injection is effective in inducing reduction of anal sphincter tone and wound healing after hemorrhoidectomy as previously stated for the treatment of chronic anal fissure. …