Treatment of a chronic rectal wound with ultrasound guided Botulinum toxin injection

What does an increased sphincter muscle tone mean, and what is a chronic rectal wound?

The rectum is closed voluntarily by an external, and involuntarily by an internal sphincter muscle (Figure 1). Sphincter spasm means that the sphincter muscles persistently have an increase tone. A chronic anal or rectal wound develops from a long standing acute wound, which gets injured again and again.

Why does an increased sphincter muscle tone and a chronic rectal wound develop?

An increased sphincter muscle tone may have several causes:

• Muscle injury
• Inflammation
• Stress
• Neurological abnormalities
• Iatrogenic causes (previous surgery, a drug side effect)

If the increased sphincter muscle tone is accompanied by other dysfunctions too, the recovery of the acute wounds, which develop during defecation, is hindered, and a chronic wound, an ulcer develops.

Symptoms of increased sphincter muscle tone, and a chronic anal rectal wound

The increased tone of a sphincter muscle does not necessarily cause any symptoms initially, but sooner or later, a feeling of discomfort presents at the perineum. If injuries develop in the anal canal, which does not dilate sufficiently, they may cause stabbing and sharp pain, fresh, red bleeding during defecation. A stinging or burning sensation often presents after passing a stool, which only goes away slowly. In case of wounds which do not heal for days, inflammation may develop, making the anal canal edematous, so susceptible, and the discharge from the wounds causes the softening and increased susceptibility of the anoderm (the skin around the rectum); this may get covered with wounds due to using paper for wiping, and wearing underwear, and eventually an inflammation develops. The commencing itching leads to additional injuries, and a vicious cycle develops. Additionally, the increased sphincter muscle tone may cause various symptoms from sudden, spontaneously presenting cramping pain to constant chronic pain, and waking up to pain at night. Constipation and sphincter muscle spasms lead to the injury of the sphincter muscle, which becomes scarred, so its function keeps deteriorating. In extreme cases, both relaxation and contraction become dysfunctional.

Treatment of increased sphincter muscle tone, chronic anal and rectal wound

The most important is to treat the cause. The wounds should be treated locally with rectal suppository containing muscle relaxants, steroids, analgesics, and antibiotics in case of an inflammation. Additionally, it is important to eliminate the causes:

• Stress relief (yoga, meditation, psychotherapy)
• Improving the perineal muscles’ function with perineal muscle exercises
• Ruling out inflammatory bowel diseases by colonoscopy
• Targeted treatment for dermatological diseases
• A strict diet, depending on the results of the food intolerance test (in case of negative results, it is still worth it to stop consuming tomato, oilseeds, coffee, gluten, alcohol, and chili).
• Using a creme containing antibiotics, and local icing in case of perianal inflammation.
• Adequate nutrition, managing conditions of deficiency.

In a significant part of the cases, symptoms go away, wounds heal, and the function of the sphincter muscle is restored with conservative treatment, and by strictly complying with the given advice. If the spasm persists, Botulinum toxin injection is recommended to prevent further complications. Usually, this is sufficient to create an adequate environment for healing due to its relaxing effect. The intervention can be complemented by refreshing the wound, or surgically loosening the lateral part of the internal sphincter (LIS: lateral internal sphincterotomy).

What kind of surgical complications may occur?

The effect of Botulinum toxin is reversible, so long term complications do not typically develop. Temporary gas incontinence may develop rarely, and bowel incontinence may develop extremely rarely. The risk of these complications is significantly higher when LIS is performed.