What Does Abdominoperineal Excision Mean?

Abdominoperineal excision (APE) is a specialized surgical procedure involving the removal of tissue from both the abdomen and the perineum. This operation is most commonly performed in the context of treating low rectal cancer, where the tumor is located near the anal canal, rendering sphincter-preserving techniques unfeasible. The procedure includes the removal of the rectum, anus, and surrounding lymphatic tissues, often resulting in the formation of a permanent colostomy.

This article provides an in-depth examination of APE, focusing on its indications, procedure, and post-operative management.

Anatomy Involved in Abdominoperineal Excision

The procedure requires the surgeon to navigate both the abdominal and perineal regions, which are interconnected through the gastrointestinal tract. The anatomy involved includes:

• Rectum: The lower part of the large intestine that stores feces before elimination. It extends into the anal canal.
• Anal Canal and Sphincters: The distal portion of the rectum, consisting of the internal and external anal sphincters, which control bowel movements.
• Pelvic Floor Muscles: Support the rectum and are involved in maintaining continence.
• Sigmoid Colon: The final section of the colon leading into the rectum.
• Perineum: The region between the genitalia and the anus that contains structures critical for both reproductive and excretory functions.

Indications for Abdominoperineal Excision

APE is primarily performed for low rectal cancer, particularly when the tumor is located too close to the anal sphincter to allow for sphincter-preserving procedures such as low anterior resection (LAR). In these cases, removing the anal canal and sphincters is necessary to achieve a clear surgical margin and prevent cancer recurrence.

Indications include:

• Low Rectal Carcinoma: Tumors located within 6 cm of the anal verge that involve or threaten the anal sphincters.
• Recurrent Rectal Cancer: In cases where rectal cancer returns after initial treatment, particularly when it is too close to the anal canal.
• Locally Advanced Anal Cancer: Some advanced anal cancers may also require abdominoperineal excision.
• Intractable Inflammatory Bowel Disease: In severe cases of ulcerative colitis or Crohn’s disease with rectal involvement, APE may be indicated when other treatments fail.

Abdominoperineal Excision Procedure

The APE procedure is complex and involves two primary surgical approaches—abdominal and perineal. The combination of these approaches allows for complete removal of the rectum, anus, and affected tissues, while also addressing surrounding structures if needed.

Step 1: Abdominal Phase

The abdominal phase is performed through an incision in the lower abdomen. Key steps include:

1. Mobilization of the Sigmoid Colon and Rectum: The surgeon carefully separates the sigmoid colon and rectum from surrounding structures, including blood vessels and nerves.
2. Lymph Node Removal: Lymph nodes are removed to evaluate cancer spread. This is crucial for determining the cancer stage and ensuring complete oncological resection.
3. Colostomy Formation: After removing the sigmoid colon and rectum, the surgeon creates a colostomy by bringing the remaining colon to the surface of the abdomen to allow waste to exit the body into an external pouch.

Step 2: Perineal Phase

The perineal phase focuses on the removal of the anal canal and adjacent tissues. Key steps include:

1. Anal Canal and Sphincter Excision: The anal canal, along with the internal and external anal sphincters, is removed. This is a critical step in ensuring that cancerous tissues are fully excised.
2. Pelvic Floor Reconstruction: In some cases, reconstruction of the pelvic floor muscles is necessary to restore structural integrity after tissue removal. This reduces the risk of complications, such as pelvic organ prolapse.
3. Closure of the Perineal Wound: After excising the necessary tissues, the perineal wound is closed, often requiring the use of flaps or specialized techniques to promote healing and reduce the risk of infection.

Post-Operative Care and Management

Post-operative care following abdominoperineal excision is intensive and requires a multidisciplinary approach, particularly in managing the patient’s new colostomy and preventing complications. Key aspects of post-operative care include:

1. Stoma Care and Education

Patients who undergo APE will have a permanent colostomy, where the end of the colon is diverted to an external stoma. Nurses and healthcare providers must educate the patient on:

• Colostomy Pouch Management: Teaching patients how to properly attach, empty, and clean the colostomy bag is crucial for maintaining hygiene and preventing infections.
• Dietary Adjustments: While most patients can return to a normal diet over time, certain foods may affect stool consistency and gas production, necessitating dietary modifications.
• Psychological Support: The presence of a permanent colostomy can have a significant emotional and psychological impact on patients. Access to counseling and support groups can help with body image issues and lifestyle adjustments.

2. Monitoring for Complications

Several complications can arise following APE, and early detection is critical for successful recovery:

• Perineal Wound Complications: Infection, delayed healing, and wound dehiscence (wound reopening) are common issues due to the location of the wound and the complexity of the surgery.
• Stoma Complications: Stoma prolapse, parastomal hernia (hernia near the stoma site), and skin irritation are potential complications requiring close monitoring and, in some cases, additional interventions.
• Urinary and Sexual Dysfunction: Due to the proximity of pelvic nerves and organs, urinary incontinence and sexual dysfunction may occur. Rehabilitation and, in some cases, further medical or surgical treatment may be necessary.

Long-Term Prognosis and Outcomes

The prognosis for patients undergoing abdominoperineal excision depends largely on the stage of the cancer at the time of diagnosis and the completeness of the tumor resection. In general, APE offers a curative option for many patients with low rectal cancer, especially when performed as part of a multimodal treatment approach that includes chemotherapy and radiation therapy.

Survival Rates and Recurrence

Studies have shown that abdominoperineal excision can achieve excellent local control of rectal cancer, with a reduction in local recurrence rates when the procedure is performed according to strict oncological principles. However, the long-term survival rate is influenced by factors such as:

• Lymph Node Involvement: Positive lymph nodes at the time of surgery are associated with a higher risk of recurrence.
• Tumor Grade and Stage: High-grade or advanced-stage tumors typically have a poorer prognosis, even after surgery.

Conclusion

Abdominoperineal excision (APE) is a life-saving procedure for patients with low rectal cancer or locally advanced anal cancer, where sphincter-preserving surgery is not possible. The complexity of the surgery, combined with the need for permanent colostomy formation, requires careful consideration of the patient’s condition, as well as comprehensive post-operative care.

While APE is a major surgical intervention with significant lifestyle implications, it remains a vital option for treating cancers of the lower rectum and anus, offering a chance for cure and long-term survival.