The Effect of Botulinum Toxin Injection After Hemorrhoidectomy in Pain Control: a Randomized Controlled Trial

Hemorrhoids are a common disease in the general population. Its prevalence is estimated to be 5-36 % and more prevalent in western countries . Half of people older than 50 years of age will suffer from hemorrhoids in a period of their life, of which only 5-10% will require surgical intervention while most of the remainders become asymptomatic and improved with the conservative treatment.

Conservative treatment in the form of diet modification as well as some medical treatment, is usually effective. On the other hand, a few patients require surgical intervention. Surgery is indicated for those not responding to conservative management, those with grade III, and grade IV hemorrhoids.

Surgical treatment is the only curative method for hemorrhoidal disease and indicated for advanced and complicated disease. The most radical operations with the best results are the Milligan-Morgan and Ferguson hemorrhoidectomy .

However, the major concern of hemorrhoidectomy is the post-operative pain that occurs in 20-40 % of patients and it is considered the main cause of refusing surgery. The cause of postoperative pain is multifactorial, including the type of anesthesia , hemorrhoidectomy technique. and spasm of the internal anal sphincter (IAS) that becomes exposed after hemorrhoidectomy. The spasm of the IAS is considered the target to relieve pain post operatively. Lateral internal sphincterotomy (LIS) is widely used as an adjunct to relieve pain post hemorrhoidectomy as it release the spasm of the sphincter and subsequently relieve pain. However, this procedure is not accepted by many surgeons due to its recorded complications as bleeding and mild degree of fecal incontinence, so its role following hemorrhoidectomy is still controversial.

On the other hand, the spasm of the anal sphincter can be abolished by injection of the botulinum toxin which acts on the acetylcholine receptor and consequently temporary muscle paralysis occurs that is followed by decreased pain and wound healing.

Our hypothesis is botulinum toxin relaxes the internal sphincter, so prevent its spasm and so reducing the pain and promoting wound healing more rapidly.