Anal Sac Excision Procedure

ImmunityQ&AMeongsiljang Veterinary Advisory Board

Anal sac excision is a surgical procedure to remove anal sacs that have developed chronic inflammation or tumors. Here’s an overview of the entire process, recovery period, and important precautions.

What is Anal Sac Excision?

A puppy lying comfortably on the examination table

Anal sac excision is a surgical procedure that removes the glands located on either side of a dog’s anus. The key consideration is that this surgery is chosen when recurrent abscesses or tumors are confirmed. For simple inflammation, initial treatment typically involves medication and flushing. However, if infections or abscesses recur two or more times, or if a tumor is suspected, surgical removal should be considered. The duration of the surgery and the required hospitalization period vary depending on the individual dog’s condition and the extent of the lesion, so it is important to have a thorough discussion with your veterinarian before the procedure.

When is Surgery Necessary?

Not all anal sac issues require surgery. Your veterinarian may recommend removal in the following situations:

Chronic anal sacculitis: When infections or abscesses recur two or more times

Anal sac rupture: When the sac ruptures through the skin, forming a fistula (abnormal passage)

Anal sac tumors: Most anal sac tumors are malignant, so early surgical removal is recommended once a tumor is confirmed

Structural abnormalities: When the ducts are too narrow or blocked, preventing proper drainage

Surgery is not recommended simply because the sacs need frequent expression.

Comparison of Incision Methods

Item	Closed	Open
Method	Incise around the sac and remove it whole	Open the sac, dissect the inner-wall mucosa, then remove
Advantages	Less contamination, faster recovery	Reliably removes even small sacs
Disadvantages	Risk of recurrence if the sac ruptures	Possible contamination of surrounding tissue
Commonly used when	General cases with inflammation or tumor	When the sac is severely adhered

Based on Fossum, Small Animal Surgery 5th Ed

Preoperative Preparation

Before surgery, a period of fasting is required to ensure the safe administration of general anesthesia. The duration of fasting and water restriction varies depending on your pet’s age, weight, and any underlying health conditions, so it is safest to follow your veterinarian’s specific instructions rather than deciding on your own. Upon arrival at the clinic, the following examinations will be performed:

Blood tests: To confirm anesthesia safety by checking liver and kidney function.

ECG and chest X-rays: Recommended for senior dogs or those with pre-existing conditions.

Perianal ultrasound: To assess the size of the anal sacs, check for adhesions, and determine the extent of any tumors.

Digital rectal examination: To evaluate surrounding lymph nodes and pelvic structures.

If an anal sac tumor is suspected, it is important to first check for hypercalcemia (elevated blood calcium levels). If present, correcting this condition before surgery is recommended. Based on the test results, the type of anesthetic drugs and the scope of the surgery will be adjusted accordingly.

A puppy receiving a pre-surgical checkup

Step-by-Step Surgical Procedure

After general anesthesia, the patient is positioned in sternal recumbency, and the perianal hair is clipped and disinfected.

Step 1: An identifying probe is inserted into the anal sac opening to confirm the boundaries of the sac.

Step 2: An elliptical incision is made in the skin overlying the sac.

Step 3: The sac is carefully dissected from the anal sphincter, with preservation of the caudal rectal nerve and blood vessels being critical.

Step 4: The sac and duct are removed en bloc.

Step 5: After hemostasis, the incision is sutured. According to veterinary surgical oncology textbooks, a single-layer closure is typically performed, with a two-layer closure applied only when there is significant tension on the suture line.

It is important to minimize tension on the suture line as much as possible. If the procedure is performed bilaterally, it takes approximately twice as long.

Complications to Watch For During Surgery

The caudal rectal nerve, which helps control defecation, runs close to the anal sacs. According to veterinary surgical textbooks, damage to this nerve can lead to temporary or permanent fecal incontinence. If only one side of the nerve is injured, recovery may occur over time as long as the other side remains intact. However, if both sides are damaged, permanent fecal incontinence may result. That’s why precise dissection by an experienced surgeon is crucial, and owners should always be informed about the risks of fecal incontinence, suture dehiscence, and infection before surgery.

Recovery Period and Home Care

The 10 to 14 days after discharge are the most critical for recovery.

Wear an e-collar: Keep it on 24 hours a day until the sutures are removed.

Monitor elimination: Check for pain during elimination or blood in the stool during the first 48 hours.

Dietary management: Feed soft wet food to keep stools soft, as constipation can strain the suture site.

Restrict walks: Limit your pet to indoor elimination only for the first five days, then allow short walks.

Wound care: Clean the incision with the prescribed antiseptic once or twice daily.

Sutures are typically removed 10 to 14 days after surgery.

A dog resting at home while wearing a neck collar.

When to Contact Your Veterinarian Immediately

Contact your veterinarian immediately if you notice any of the following symptoms during the recovery period: - Bleeding, pus, or severe swelling at the suture site - Inability to defecate for more than 24 hours or persistent constipation - Fecal incontinence (involuntary loss of bowel control) - Fever (above 39.5°C) or complete loss of appetite - Persistent dragging or rubbing of the hindquarters on the floor Fecal incontinence, in particular, may indicate nerve damage and requires prompt re-evaluation by your veterinarian.

Risk of Recurrence After Surgery

According to veterinary surgery textbooks, complete removal of both anal sacs prevents recurrence of anal sacculitis. However, if part of the sac wall remains during surgery, fistulas or abscesses may rarely recur. In cases of tumors (anal sac adenocarcinoma), local recurrence or lymph node metastasis can occur even after complete excision, making regular check-ups essential. The follow-up examination schedule varies depending on the presence of tumors and the condition of the lesions, so it is important to establish a check-up plan with your veterinarian after surgery.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can bowel movements be affected after surgery?

Most pets resume normal bowel movements. In rare cases, temporary fecal incontinence may occur, but if only one pudendal rectal nerve is damaged, the intact contralateral nerve typically allows for recovery within 4 to 6 weeks. However, if both nerves are injured, permanent fecal incontinence can result, so it is important to discuss your pet’s individual risk with your veterinarian before surgery.

Is it okay to have surgery on just one side?

If the problem is confined to one side, it may be possible to remove only that affected gland. However, anal sac excision is commonly described as a procedure involving the removal of both glands, so bilateral excision is often recommended for chronic or recurrent cases. The precise extent of the resection will be determined by your veterinarian based on the location and condition of the lesions.

How much does the surgery cost?

Costs vary depending on the clinic, your pet’s weight, and whether the procedure is performed on one or both sides. For an accurate estimate, please check directly with your veterinarian. We recommend being cautious of any quoted prices that lack a clear source.

Is there any alternative to surgery?

Simple inflammation can be managed with antibiotics, cleaning, and dietary changes. However, if the condition recurs frequently or if a tumor is present, surgical removal is the definitive solution.

Is surgery an option for senior dogs?

We can proceed if blood and cardiac tests show no anesthesia risks. In fact, when diagnosing tumors, the progression of the disease is a more critical factor than age.