Fat Tissue Injection Shows Promise for Complex Anal Fistula

Pilot Study Tests Natural Healing Approach for Difficult Fistulas

Complex anal fistulas are abnormal tunnels that form between the anal canal and the skin near the anus. They are called "complex" when they involve a large portion of the sphincter muscle or have other complicating factors. Traditional treatments often fail or risk damaging the muscles that control bowel function. This Italian pilot study tested whether injecting specially processed fat tissue from the patient's own body could help heal these challenging fistulas safely.

19 Patients Treated Over 20-Month Study Period

Researchers at Cisanello University Hospital in Pisa, Italy, enrolled 19 patients with complex anal fistulas between April 2015 and December 2016. All patients had fistulas confirmed by MRI or ultrasound imaging. The group was divided into two categories: twelve patients receiving this as their first sphincter-saving treatment, and seven patients who had already tried other treatments that failed. A temporary seton (a small thread placed through the fistula) was positioned four to six weeks before the main procedure.

Treatment Combines Fat Injection with Internal Closure

The procedure involved two key steps. First, doctors harvested fat tissue from the patient's abdomen using gentle liposuction. This fat was then processed using the Lipogems® device, which breaks down the fat into tiny fragments while washing away blood and oil. The processed tissue contains pericytes (helper cells that support healing) and other regenerative cells.

Second, surgeons cleaned the fistula tract and closed the internal opening with stitches. They then injected approximately six milliliters of the processed fat tissue around the internal opening and along the fistula tract. The average procedure took about 55 minutes.

Nearly Three-Quarters of Patients Healed Successfully

After an average follow-up of nine months, the overall healing rate reached nearly 74 percent. Results differed between the two patient groups:

• First-time treatment group: 83 percent healed successfully

• Previously failed treatment group: 57 percent healed successfully

Healing was defined as complete closure of both the internal and external openings with no discharge.

Minimal Side Effects and Low Pain Scores Reported

The treatment proved safe with very few complications. Patients reported low pain levels, averaging just two out of ten on a standard pain scale. The study recorded:

• No serious infections or sepsis

• No bleeding requiring treatment

• No damage to bowel control

• Only three minor bruises on the abdomen (all healed without treatment)

• One perianal abscess

No difficulties occurred during the procedure itself, and the technique was described as reproducible and straightforward.

What This Means for Your Treatment Decision

This pilot study suggests that micro-fragmented adipose tissue injection may offer a safe and effective option for complex anal fistulas. The treatment uses your own tissue, which eliminates rejection risks. The procedure is minimally invasive, and patients experienced little discomfort afterward.

However, this was a small study without a comparison group, so results should be interpreted cautiously. Patients who had not tried other treatments showed better outcomes than those with previously failed procedures. If you are considering this approach, discuss with your doctor whether you might be a good candidate, especially if this would be your first sphincter-saving treatment.

The researchers concluded that this method is safe, feasible, and may enhance healing for complex anal fistulas. Larger studies with longer follow-up periods would help confirm these encouraging early results.

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Source: Naldini et al., Techniques in Coloproctology, 2018.