Understanding Sphincterotomy: Treatment for Chronic Anal Fissures

Sphincterotomy, particularly lateral internal sphincterotomy (LIS), is considered the gold standard surgical treatment for chronic anal fissures that do not respond to conservative management. This procedure has proven highly effective in reducing pain and promoting healing by alleviating the hypertonicity of the internal anal sphincter, which is often responsible for the persistence of anal fissures.

This article provides a comprehensive overview of sphincterotomy for anal fissures, covering its indications, preoperative evaluation, contraindications, surgical techniques, postoperative care, potential complications, alternative treatments, prognosis, and recent advances. The aim is to provide surgeons with detailed information to ensure optimal patient outcomes.

Indications for Sphincterotomy

Sphincterotomy is typically indicated in patients with chronic anal fissures that have not responded to at least six weeks of conservative management. Conservative treatments may include dietary modifications, sitz baths, topical anesthetics, and pharmacological therapies such as topical nitrates or calcium channel blockers. Patients experiencing recurrent fissures, severe pain, or significant impact on quality of life despite conservative measures are prime candidates for sphincterotomy.

Specific Indications Include:

1. Chronic anal fissure lasting more than 6-8 weeks.
2. Recurrent anal fissures.
3. Fissures associated with sentinel skin tags or hypertrophied anal papillae.
4. Failure of medical therapy, including topical ointments and botulinum toxin injections.
5. Severe anal pain disrupting daily activities or causing significant distress.

Preoperative Evaluation

A thorough preoperative evaluation is critical to identifying candidates who will benefit most from sphincterotomy and to minimizing the risk of complications. This evaluation should include:

1. Medical History:
   • A detailed history of symptoms, including the duration of the fissure, previous treatments, and their effectiveness.
   • Any history of previous anorectal surgeries or conditions that may impact healing, such as Crohn's disease.
2. Physical Examination:
   • Visual inspection of the anus to confirm the presence of a fissure, typically located posteriorly in the midline.
   • Palpation to assess for hypertonicity of the internal sphincter and any associated complications, such as a sentinel pile or fistula.
3. Anoscopy or Sigmoidoscopy:
   • These diagnostic procedures may be used to exclude other conditions, such as hemorrhoids, malignancy, or inflammatory bowel disease, which could present with similar symptoms.
4. Patient Counseling:
   • Discuss the nature of the procedure, potential risks, benefits, and alternative treatments.
   • Set realistic expectations regarding postoperative recovery and the likelihood of symptom resolution.

Contraindications

While sphincterotomy is highly effective, it is not suitable for all patients. Contraindications include:

1. Active Inflammatory Bowel Disease: Patients with Crohn's disease or ulcerative colitis may have an increased risk of poor wound healing and complications.
2. Immunocompromised Patients: Individuals with compromised immune systems may experience delayed healing and a higher risk of infection.
3. Previous Sphincter Surgery: Patients who have undergone previous sphincter surgery may have an increased risk of incontinence postoperatively.
4. Fissures Associated with Malignancy: If malignancy is suspected, biopsy and appropriate oncological treatment should be prioritized.
5. Poor Anal Sphincter Function: Patients with pre-existing anal incontinence or weak sphincter tone may be at higher risk for worsening incontinence after sphincterotomy.

Surgical Techniques and Steps

The most common surgical technique for treating anal fissures is the lateral internal sphincterotomy. This procedure can be performed using either an open or closed technique, depending on the surgeon's preference and the specific circumstances of the case.

Open Lateral Internal Sphincterotomy

1. Anesthesia:
   • The procedure is typically performed under local anesthesia with sedation, regional anesthesia, or general anesthesia, depending on patient and surgeon preference.
2. Positioning:
   • The patient is positioned in the lithotomy or left lateral position, allowing optimal access to the anal region.
3. Incision:
   • A small incision is made at the lateral aspect of the anoderm, usually at the 3 o'clock or 9 o'clock position, away from the fissure site.
4. Sphincterotomy:
   • The internal anal sphincter is identified and a controlled incision is made to partially divide it. The extent of the division should be sufficient to relieve sphincter pressure without causing incontinence.
5. Wound Management:
   • The wound is left open to heal by secondary intention, which allows drainage and reduces the risk of infection.

Closed Lateral Internal Sphincterotomy

1. Anesthesia and Positioning:
   • The procedure setup is similar to the open technique.
2. Submucosal Dissection:
   • A small stab incision is made in the intersphincteric groove. A scalpel or a sphincterotome is then inserted to cut the internal sphincter muscle blindly, without direct visualization.
3. Incision Closure:
   • The skin incision is usually closed with a single absorbable suture, although some surgeons prefer to leave it open.

Postoperative Care

Postoperative management focuses on pain control, wound care, and prevention of complications. Key aspects include:

1. Pain Management:
   • Analgesics, such as NSAIDs or acetaminophen, are typically sufficient for managing postoperative pain. Narcotics should be used sparingly due to the risk of constipation.
2. Dietary Recommendations:
   • Patients should be advised to maintain a high-fiber diet and drink plenty of fluids to prevent constipation and reduce strain during bowel movements.
3. Sitz Baths:
   • Warm sitz baths several times a day can help soothe the anal area, reduce pain, and promote healing.
4. Wound Care:
   • The surgical site should be kept clean and dry. Patients may be instructed to gently cleanse the area after bowel movements.
5. Activity Restrictions:
   • Patients should avoid heavy lifting, strenuous activity, and long periods of sitting for the first few weeks postoperatively.
6. Follow-Up:
   • A follow-up appointment is typically scheduled 2-4 weeks postoperatively to assess wound healing and address any complications.

Possible Complications

Although sphincterotomy is generally safe, it carries risks like any surgical procedure. The most common complications include:

1. Incontinence:
   • The most significant concern is fecal incontinence, particularly to flatus or liquid stool. The risk varies depending on the extent of sphincter division and the patient's baseline sphincter function.
2. Infection:
   • Superficial wound infections can occur but are usually manageable with local care and antibiotics if necessary.
3. Bleeding:
   • Minor bleeding is common but typically self-limited. Persistent or significant bleeding may require surgical intervention.
4. Anal Stenosis:
   • Although rare, improper wound healing can lead to anal stenosis, which may require further surgical correction.
5. Recurrence of Fissure:
   • While sphincterotomy has a high success rate, there is a small risk of fissure recurrence, particularly if contributing factors like constipation are not addressed.

Alternative Treatments

For patients who are not candidates for sphincterotomy or prefer less invasive options, several alternatives exist:

1. Botulinum Toxin Injection:
   • Botulinum toxin can be injected into the internal sphincter to induce temporary paralysis, reducing sphincter pressure and promoting fissure healing. This method is less effective than sphincterotomy and may require repeated treatments.
2. Topical Pharmacotherapy:
   • Topical nitroglycerin or calcium channel blockers (e.g., diltiazem, nifedipine) can be applied to relax the internal sphincter and improve blood flow to the fissure site.
3. Anal Dilators:
   • Gradual anal dilation can reduce sphincter pressure, but its effectiveness is limited, and it may cause discomfort.
4. Fissurectomy:
   • In some cases, simple excision of the fissure (fissurectomy) may be performed, although it is less common and typically reserved for specific indications.

Prognosis and Outcome

The prognosis following sphincterotomy is generally excellent, with most studies reporting success rates of 90-95% for chronic anal fissures. Most patients experience significant pain relief and healing within a few weeks. Long-term outcomes are favorable, with low rates of fissure recurrence and minimal impact on continence.

Average Cost

The cost of sphincterotomy can vary widely depending on geographic location, healthcare setting, and insurance coverage. In the United States, the procedure may range from $3,000 to $7,000, including surgeon's fees, anesthesia, and facility charges. Patients should be counseled on the financial aspects of the procedure and potential out-of-pocket costs.

Recent Advances

Recent advances in the management of anal fissures include:

1. Improved Imaging Techniques:
   • High-resolution anal manometry and endoanal ultrasound have enhanced the preoperative assessment of sphincter function, allowing for better patient selection and outcome prediction.
2. Minimally Invasive Techniques:
   • The development of minimally invasive techniques, such as endoscopic sphincterotomy, offers the potential for reduced postoperative pain and faster recovery, though these techniques are still under investigation.
3. Pharmacological Enhancements:
   • Ongoing research into novel pharmacological agents, such as topical nitric oxide donors and combination therapies, may offer additional non-surgical options for managing chronic fissures.

Conclusion

Lateral internal sphincterotomy remains the most effective surgical treatment for chronic anal fissures, providing substantial pain relief and promoting healing in the majority of patients. With careful patient selection, thorough preoperative evaluation, and proper surgical technique, the risks of complications, including incontinence, can be minimized. Surgeons should stay informed about recent advances and alternative treatments to offer the best possible care for their patients.