Anal Sacculectomy

Anal sacculectomy is indicated when one or both sacs cause ongoing problems that cannot be controlled with regular manual expression, antibiotics, or flushing. Specific indications include:

• Frequently recurring impaction or infection despite frequent manual expression
• Anal sac abscess or chronic fistula (draining tract)
• Anal sac adenocarcinoma — a malignant tumor that requires complete removal with the widest possible margins
• Sacs that have ruptured and will not heal with medical care

The surgery is definitive — once removed, the sacs cannot become infected again. It is elective (planned) for chronic benign disease and urgent for suspected or confirmed adenocarcinoma.

The procedure is performed under general anesthesia, typically in dorsal or sternal recumbency. Steps include:

• A cannula or probe is inserted into the anal sac duct to identify and outline the sac
• A careful elliptical incision is made around the duct opening and the sac is dissected free from the surrounding tissue
• Special care is taken to avoid the caudal rectal nerve and the external anal sphincter, which run close to the sac
• Bleeding is controlled with cautery, and the tissues are closed in layers
• Tumor cases receive wider tissue margins; the specimen is submitted to pathology

Both sacs can be removed during the same anesthetic episode, though in some situations the surgeon may recommend staging them to reduce the risk of bilateral sphincter complications.

Pre-operative preparation depends on the indication. For suspected anal sac adenocarcinoma, abdominal ultrasound and chest radiographs are performed before scheduling surgery to check for metastasis (spread) to the iliac lymph nodes or lungs. For benign disease, standard bloodwork and a physical examination are sufficient. A rectal exam under sedation is often performed to confirm anatomy. Food is withheld the night before surgery; an enema may be administered to clear fecal material near the surgical field.

Most pets go home the same day or after one overnight stay. The perineal area heals over one to two weeks:

• Days 1–5: some swelling and discomfort around the anus; pain medication; e-collar to prevent licking
• Days 3–10: stool softeners help prevent hard stools from stressing the incision
• Week 2: suture recheck; incision is typically well-healed by day fourteen

For adenocarcinoma cases, pathology results guide discussions about whether chemotherapy consultation or monitoring for lymph node recurrence is appropriate. Routine recheck exams are scheduled accordingly.

The most significant potential complication of anal sacculectomy is fecal incontinence resulting from damage to the caudal rectal nerve or external anal sphincter. With careful technique, the incidence is low, but it is a recognized risk — particularly when anatomy is distorted by abscess or tumor. Temporary fecal incontinence (lasting days to weeks) is more common than permanent. Other possible complications include wound infection, seroma, and — specific to cancer cases — incomplete excision requiring further treatment. Because the anal sacs are embedded near critical structures, this procedure is best performed by a surgeon experienced in perineal anatomy.