What is a FiLaC fistula procedure?

September 21, 2025 •

4 min read

First described in 2011, the FiLaC (Fistula Laser Closure) fistula procedure is a minimally invasive, sphincter-sparing technique for treating anal fistulas. It uses a flexible laser probe to destroy and seal the fistula tract from within, significantly reducing trauma to surrounding healthy tissue. This advanced method aims to achieve a high success rate while preserving anal continence, addressing a major concern with more traditional surgical approaches.

Quick Summary

The FiLaC fistula procedure employs a special diode laser with a radial-emitting fiber to destroy and collapse the epithelialized tract of an anal fistula from the inside. This minimally invasive technique is designed to seal the fistula while preserving the crucial anal sphincter muscles, which minimizes the risk of incontinence.

Key Points

Minimally Invasive: The FiLaC procedure uses a laser fiber inserted into the fistula tract, avoiding the need for large incisions and reducing tissue damage compared to traditional surgery.
Sphincter-Sparing: The technique is designed to destroy the fistula tract without cutting or damaging the delicate anal sphincter muscle, preserving continence.
Radial Laser Energy: A key feature is the radial-emitting probe that distributes laser energy evenly along the entire fistula tract, ensuring comprehensive destruction of the diseased tissue.
Faster Recovery: Most patients experience less pain, a shorter hospital stay (often outpatient), and a quicker return to normal activities after the FiLaC procedure.
Complex Fistula Treatment: FiLaC is a particularly valuable option for treating complex anal fistulas, especially those with previous surgical failures, where continence preservation is a priority.
Combines with Other Techniques: For some complex cases, FiLaC can be combined with an advancement flap to improve success rates.

What is an Anal Fistula?

An anal fistula is a small, hollow tunnel that develops between the end of the bowel and the skin near the anus. Most fistulas are the result of an abscess (a collection of pus) that forms in one of the small anal glands and then tracks to the skin. Symptoms can include persistent pain, swelling, and drainage of pus or bloody discharge. While some simple fistulas can be treated with a fistulotomy (laying the tract open), complex fistulas that involve a significant portion of the anal sphincter muscle require a more delicate, sphincter-sparing approach to prevent future incontinence. The FiLaC procedure was developed to specifically address this need, offering a treatment that ablates the fistula tract without cutting through the muscle.

The Mechanism Behind the FiLaC Procedure

Fistula Laser Closure (FiLaC) is a sophisticated procedure that utilizes a precise laser to treat the fistula tract. The key steps are as follows:

Fistula Tract Identification: The surgeon first identifies and thoroughly cleans the entire fistula tract, from the internal opening inside the anal canal to the external opening on the perianal skin. The tract is flushed and any granulation tissue is removed.
Laser Fiber Insertion: A thin, flexible radial laser probe is inserted into the external opening and guided through the tract until it reaches the internal opening. A key feature of this probe is its radial-emitting tip, which ensures the laser energy is distributed evenly around the entire circumference of the tract.
Tissue Ablation: As the surgeon slowly and systematically withdraws the laser probe, the device emits a controlled dose of laser energy. This thermal energy destroys the epithelial lining and scar tissue inside the tract through a combination of coagulation and shrinkage.
Tract Sealing: The heat from the laser causes the remaining tissue to coagulate and contract, effectively sealing the tract behind the retreating probe. The internal opening is sometimes closed with a suture or advancement flap, while the external opening is left open to allow for continued drainage. This prevents a build-up of fluid that could lead to another abscess.

FiLaC vs. Traditional Fistula Surgery: A Comparison

To understand the advantages of the FiLaC procedure, it helps to compare it to conventional surgical methods like fistulotomy or seton placement. The choice of procedure often depends on the complexity of the fistula and the patient's individual anatomy and risk factors.


Feature	FiLaC Procedure	Traditional Surgery (e.g., Fistulotomy)
Invasiveness	Minimally invasive; no cutting of sphincter muscle.	More invasive, often requiring incision through the sphincter muscle.
Sphincter Impact	Sphincter-sparing; preserves the anal sphincter, minimizing the risk of incontinence.	Risk of Continence Issues; cutting the sphincter can lead to a risk of fecal incontinence.
Post-operative Pain	Typically minimal due to minimal tissue trauma.	Often more significant pain due to the larger incision.
Recovery Time	Faster recovery and earlier return to daily activities.	Longer recovery period, requiring more extensive wound care.
Healing Process	Healing occurs gradually as the sealed tract fibroses over several weeks to months.	Wounds heal more openly over time, requiring careful dressing and hygiene.
Recurrence Rate	Promising results, but can vary, with potential for repeat procedures.	Varies based on technique and fistula complexity.

Advantages and Considerations for FiLaC

FiLaC is considered a modern, safe, and effective treatment for many types of anal fistulas, particularly complex or recurrent cases. The primary advantages include:

Sphincter Preservation: The single most important benefit is the preservation of the anal sphincter muscle, which directly reduces the risk of long-term fecal incontinence.
Minimally Invasive: The procedure involves minimal trauma, resulting in less pain and discomfort during recovery.
Faster Recovery: Patients generally experience a shorter hospital stay (often discharged the same day) and can return to their normal routine sooner than with traditional surgery.
Repeatable if Necessary: If the procedure is not fully successful the first time, it can be repeated without compromising the sphincter.

However, there are also considerations to discuss with a surgeon. The success rate can depend on the complexity and size of the fistula tract. While studies have shown good outcomes, results can vary, and recurrence is still a possibility. For very wide or complex tracts, FiLaC may be combined with other techniques, such as an advancement flap, to improve the outcome. It is essential for a patient to have a thorough evaluation, including MRI imaging, to determine if FiLaC is the most appropriate treatment option.

Preparing for and Recovering from the Procedure

Before the FiLaC procedure, patients will typically undergo imaging, such as an MRI, to map the fistula tract accurately. Your doctor may also recommend preparatory steps like bowel cleansing.

The recovery period for FiLaC is generally shorter and less painful than for traditional fistula surgery. Patients may be given antibiotics and pain medication and will be instructed on proper wound care, which often involves sitz baths. While some discomfort and mild discharge are normal in the initial weeks, most patients can resume daily activities quickly. Full healing, however, can take several months, and follow-up appointments are crucial to monitor progress and check for any signs of recurrence.

Conclusion

The FiLaC fistula procedure represents a significant advancement in the treatment of anal fistulas, offering a minimally invasive, sphincter-sparing option with a good safety profile and high patient satisfaction rates. Its ability to effectively treat complex fistulas while prioritizing the preservation of continence makes it a valuable tool for colorectal surgeons. While not suitable for all cases, and with success rates that can vary, FiLaC is a promising option for many patients seeking a gentler path to recovery. For more detailed clinical information on the effectiveness and long-term outcomes of FiLaC, authoritative medical sources can provide further insight, such as this review on emerging data from the National Institutes of Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8664604/.

Frequently Asked Questions

A fistulotomy involves cutting open the fistula tract, which can sometimes damage the anal sphincter and potentially lead to incontinence. FiLaC is a minimally invasive, sphincter-sparing procedure that uses a laser to close the tract without cutting, which preserves muscle function.

Recovery is generally faster than with traditional surgery. Most patients can return to daily activities within a few days to weeks. The full healing of the tract, however, can take several months.

Compared to more invasive surgeries, the FiLaC procedure typically results in minimal postoperative pain and discomfort due to the reduced tissue damage. Pain can be managed with over-the-counter or prescribed medication.

Success rates vary depending on the type and complexity of the fistula, but studies have reported favorable long-term outcomes. For complex cases, combining FiLaC with other techniques like an advancement flap can improve success rates.

FiLaC is highly effective for many anal fistulas, especially complex ones where sphincter preservation is critical. However, it may not be the optimal choice for every patient. A colorectal surgeon must evaluate the specific fistula characteristics to determine the best treatment plan.

While considered safe, risks include a chance of recurrence, especially if the tract is very large or complex, or if there are secondary tracts that are missed. Complications like bleeding, infection, and abscess can also occur, though they are often less common than with more invasive procedures.

Coverage for the FiLaC procedure varies depending on your specific insurance policy and geographic location. It is best to contact your insurance provider directly to confirm coverage and understand any out-of-pocket expenses.