Anal Fistula Diagnosis, Treatment & Cost

✅Diagnostic Tests For Anal Fistula

Based on the above information, a gastroenterologist (or colorectal surgeon) may advise diagnostic tests to detect infections or rule out serious conditions such as cancer. The following are the tests that might be recommended to diagnose an anal fistula:

• Laboratory findings
• Complete blood count (CBC)
• C-reactive protein (CRP)
• Endoscopic evaluations
• Fistula probe
• Anoscopy
• Proctoscopy or sigmoidoscopy
• Imaging studies
• Magnetic resonance imaging (MRI)
• Computed tomography (CT) scan/ CT fistulography
• Endoanal or endorectal ultrasound (EAUS)
• Barium enema/small-bowel series
• Fistulography
• Functional assessment
• Anorectal manometry
• Additional diagnostic methods
• Examination under anesthesia (EUA)
  
  

Laboratory findings

Anal fistula is mainly diagnosed via clinical examination and imaging, laboratory tests are used to assess the presence of infection, inflammation, or underlying systemic disease. These tests include: -

Complete blood count (CBC)

A CBC helps in assessing signs of infection or inflammation that might be associated with an anal fistula. Elevated WBC or leukocytosis often indicates the presence of infection, which is common in patients with active fistulas or associated abscesses. While CBC cannot directly confirm a fistula, it gives supporting evidence of an underlying infectious process, which can be used to guide further diagnostics.

C-reactive protein (CRP)

C-reactive protein is an inflammation marker in the body. High CRP levels can point toward ongoing infection or inflammatory activity within the perianal region. In an anal fistula, an elevated CRP suggests that there may be an active inflammatory tract or an associated abscess.

Endoscopic evaluations

Endoscopic evaluation plays a key role in the diagnosis of anal fistula as it allows direct visualization of the anal canal and rectum, helping to detect internal openings or associated mucosal abnormalities. Since fistulas are directly linked to underlying conditions such as Crohn’s disease, malignancy, and TB, endoscopic procedures reveal important information about the presence of inflammation, ulcers, or strictures. This method not only confirms the presence of a fistula but also helps rule out other anorectal pathologies that may exhibit similar symptoms.

This includes:

Fistula probe

A fistula probe is mainly used to detect the presence of an anal fistula tract. When inserted through a suspected external opening, if the probe identifies a tract connecting to the anal canal, it confirms the presence of a fistula. 

Anoscopy

Anoscopy is a simple endoscopic procedure in which a short, rigid tube called an anoscope is inserted into the anal canal. It allows the doctor to directly visualize the anal canal and identify any internal anal fistula. This procedure is especially useful for detecting small fistula openings that may not be visible from the outside. By ruling out other causes of anal pain or discharge, such as haemorrhoids or fissures, anoscopy helps in narrowing the diagnosis toward or away from an anal fistula.

Proctoscopy or sigmoidoscopy

Proctoscopy or sigmoidoscopy involves using longer endoscopic instruments to inspect the mucosal surfaces of the rectum and sigmoid colon. These procedures are useful in excluding other anorectal disorders or IBD like Crohn’s disease, which are frequently associated with complex or recurrent anal fistulas. 

While proctoscopy and sigmoidoscopy do not directly visualise fistulous tracts, they are useful for screening out intrarectal diseases or cancers that may resemble or coexist with fistulas. Their role is complementary to anoscopy and high-resolution imaging such as MRI, which remains the gold standard for detailed fistula mapping.

Imaging Studies

Imaging is critical for correctly identifying the fistula tract, detecting abscesses, and determining anal sphincter involvement. It is especially valuable in difficult or recurring cases since it helps plan suitable surgical treatment.

Magnetic resonance imaging (MRI)

MRI is recognized as the gold standard for diagnosing or ruling out an anal fistula. It gives excellent soft tissue contrast and allows doctors to see both the primary fistula tract and any secondary extensions or abscesses. Importantly, anal fistula MRI shows the exact relationship of the tract with the anal sphincter muscles, which is critical in planning surgery. If MRI does not show any abnormal tracts, fluid collections, or communication between the anal canal and skin, an anal fistula can confidently be ruled out.

Computed tomography (CT) Scan / CT fistulography

A CT scan can be helpful in detecting perianal abscesses and fistulas, especially in patients with Crohn’s disease or deep pelvic sepsis. When combined with fistulography (where contrast is injected into an opening before CT imaging), the tract can be visualized more clearly. However, CT has lower sensitivity compared to MRI for small or superficial fistulas. If no tract or abnormal course of contrast is identified during CT fistulography, the likelihood of an anal fistula is low.

Endoanal or endorectal ultrasound (EAUS)

Endoanal or endorectal ultrasound involves placing a high-frequency probe inside the anal canal or rectum. This technique provides good visualization of the anal sphincter complex and any fistulous tracts passing through or around the muscles. With 3D technology, the accuracy increases further, making it particularly useful for simple fistulas. If EAUS shows a normal sphincter structure with no abnormal tracts or collections, the presence of a fistula can be excluded.

Barium Enema / Small-Bowel Series

Although rarely used today for anal fistulas, a barium enema involves filling the colon and rectum with a contrast material to detect abnormal passages. It is more commonly used to assess conditions such as Crohn’s disease, diverticulitis, or tumours. In rare cases, it can demonstrate an abnormal connection (fistula) from the bowel to the skin. If contrast passes smoothly through the colon without leakage, it suggests that a fistula is not present. However, this test is not very reliable compared to MRI or ultrasound.

Fistulography

Fistulography is an imaging technique where contrast dye is directly injected into an external fistula opening, and then X-rays are taken to outline the tract. It can show the location and direction of the fistula, but has limits in detecting deep extensions or sphincter involvement. If no tract is observed following contrast injection, it indicates there is no fistula is present. Due to its limitations, fistulography is now less commonly used, with MRI largely replacing it in clinical practice.

Functional Assessment

This assessment provides complete evaluation of patients with anal fistulas, particularly when considering surgical intervention. Whereas imaging and endoscopic tools primarily define the anatomical characteristics of the fistula tract, functional studies such as anal manometry provide essential information about the integrity and function of the anal sphincter complex. This includes:

Anorectal manometry

Anorectal manometry or anal manometry is a test that measures how well the muscles around the anus (the anal sphincters) are working. It checks the pressure these muscles create, as well as how sensitive the rectum is and how it responds to signals. While this test doesn't directly show if a person has an anal fistula, it is still very helpful before surgery. If the fistula is close to or goes through the muscles that control bowel movements, anal manometry can show if those muscles are already weak.  This helps doctors choose the safest surgical method. For example, if the muscles are weak, doctors might avoid cutting them and instead use a technique that protects them. In this way, this test helps to reduce the risk of problems like incontinence after surgery.

Additional Diagnostic Methods

While a thorough clinical history and physical examination are sufficient enough to diagnose an anal fistula, additional diagnostic methods are necessary in cases where the fistula is complex, recurrent, or not clearly evident on initial examination.

Examination under anesthesia (EUA)

Examination under anaesthesia (EUA) is considered the gold standard for the diagnosis and assessment of anal fistulas, especially in complex or recurrent cases. EUA allows for a thorough and pain-free evaluation of the perianal area, which is often not possible in a fully conscious patient due to discomfort or pain.

✅Differential Diagnosis of Anal Fistula

✅Considerations of a Gastroenterologist for Treating Anal Fistula

✅Anal Fistula Treatment Goals

Need clarity on anal fistula diagnosis or the treatment options? Get a free second opinion today.

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A gastroenterologist or a colorectal surgeon may choose the appropriate treatment for an anal fistula based on the fistula's complexity, location, underlying anal fistula causes, and the patient's overall health status. The treatment plan also takes into account the risk of recurrence and the need to preserve sphincter function. Several management options are available, particularly for symptomatic or complex fistulas. The most commonly used anal fistula management includes:

• Non-pharmacological management
• Lifestyle and dietary modifications
• Sitz bath
• Ensuring proper hygiene
• Pharmacological management
• Antibiotics
• Immunosuppressive therapy
• Anti-tumour necrosis factor (anti-TNF) agents
• Analgesics 
• Surgical interventions
• Fibrin plug and glue (anal fistula plug)
• Ligation of the intersphincteric anal fistula tract (LIFT)
• Seton Placement
• Endorectal advancement flap
• Fistulotomy
• Fistulectomy
• VAAFT (video-assisted anal fistula treatment)

Non-pharmacological management

Non-pharmacological management forms an important part of the overall treatment strategy for anal fistula. These include: -

Lifestyle and dietary modifications

Adopting a high-fibre diet, staying hydrated, and avoiding excessive straining during bowel movements help keep stools soft and regular. This reduces pressure on the anal area, prevents constipation, and lowers irritation around the fistula. These steps helps to support healing and decreases the risk of recurrent infections.

Sitz bath

Warm sitz baths (sitting in warm water for 10 to 15 minutes several times each day) relieve pain, enhance local blood circulation, and aid in the removal of leftover pus or discharge. The moist heat also relaxes the anal sphincter muscles, which relieves pain and promotes speedier tissue repair.

Ensuring proper hygiene

Maintaining good perianal hygiene by gently cleansing the area after bowel movements, which helps to prevent bacterial growth and secondary infections. Using mild, non-irritating cleansers or plain water keeps the wound clean, cuts down on odour, and reduces skin irritation. These steps help with healing and make the patient more comfortable.

Pharmacological management

Pharmacological management of anal fistula mainly focuses on controlling infection, reducing inflammation, and managing associated symptoms. Anal fistula medicine generally comprises the following:

Antibiotics

These medications are used to control infection and reduce symptoms related to anal fistulas, in cases complicated by abscess or sepsis. While antibiotics help reduce inflammation, bacterial load, and fistula drainage, they usually do not cure the fistula alone. They are prescribed after abscess drainage procedure to prevent fistula formation or recurrence and are often used in combination with other therapies in Crohn's disease patients.

Immunosuppressive therapy

Immunosuppressive therapy is used for anal fistulas that are related to Crohn's disease. These agents help control the underlying inflammatory process by modifying the immune response, promoting healing, and reducing inflammation of fistulous tracts. However, these drugs take several months (3–6 months) to show an effect and are typically used in combination with antibiotics or biologics. Some evidence also supports their perioperative use to improve surgical outcomes by decreasing immune-mediated complications.

Anti-tumour necrosis factor (anti-TNF) agents

Anti-TNF medications are biologic therapies that inhibit tumour necrosis factor-alpha, a major cytokine involved in Crohn's disease inflammation. They are recognised as the cornerstone of medical treatment for Crohn 's-related anal fistulas. Response rates are improved when combined with antibiotics. Anti-TNF agents can be given intravenously or subcutaneously and require ongoing monitoring for efficacy and adverse effects.

Analgesics

Pain control is an essential for the management of anal fistula. Commonly used are analgesics, or nonsteroidal anti-inflammatory drugs (NSAIDs), that do not treat the fistula directly but relieve pain, improve comfort, and support recovery by allowing patients to tolerate other treatments like sitz baths or wound care.

Surgical interventions/ anal fistula surgery

Surgery is the main effective treatment for anal fistula, especially when the fistulous tract is complex, chronic, or associated with recurring infections. The choice of surgical technique depends on the type and location of the fistula, as well as patient-specific factors such as the patient's continence status and underlying medical conditions. 

These include: -

Fibrin plug and glue (anal fistula plug)

Anal fistula plugs are biomaterials inserted into the fistula tract to seal it and promote healing without cutting the sphincter muscles. The plug acts as a scaffold for tissue ingrowth, helping close the tract and prevent faecal matter from entering, thus reducing infection. These techniques aim to preserve sphincter function with minimal morbidity.

Ligation of the intersphincteric anal fistula tract (LIFT)

In this procedure, the fistula tract is located between the sphincter muscles and is tied off securely. This closes the connection between the internal and external openings, stopping the infection from spreading. The surgery preserves the sphincter muscles, so it helps maintain normal bowel control and has good healing success, especially in transsphincteric fistulas.

Seton Placement

Setons are thin threads or soft rubber bands that are placed through a fistula (an abnormal tunnel in the body). They help keep the tunnel open so that fluid and infection can drain out properly. This prevents pus from building up, reduces swelling and infection, and helps the area heal slowly and safely. Setons are utilised as a temporary treatment before doing the main surgery to fully close the fistula.

There are two main types of setons used in anal fistula treatment: -

• Loose seton, which controls infection and allows fibrosis while keeping the tract open.
• Cutting seton, which gradually cuts through the sphincter while scar tissue forms, reducing damage to anal muscles.

Setons are often used in complex or Crohn's-related fistulas, either as definitive treatment or as a bridge before more definitive surgery.

Endorectal advancement flap

This technique involves excising the internal fistula opening and covering it with a flap of rectal mucosa and submucosa advanced over the defect. It preserves sphincter function by avoiding muscle division. The flap promotes healing of the internal opening and closure of the tract.

Fistulotomy

Fistulotomy is the most commonly performed surgery for anal fistula, where the entire fistula tract is opened up by cutting through the overlying tissue and allowing it to heal by secondary intention. It is highly effective for low, simple anal fistulas with healing rates over 90%. However, for high or complex fistulas, it risks sphincter damage and faecal incontinence, so its use is limited in those cases.

Fistulectomy

This procedure involves the complete excision of the fistula tract, unlike fistulectomy, which opens it. It removes the entire tract and nearby tissue, which lowers the risk of recurrence, however, it is a more invasive procedure. This procedure carries an increased risk of infection, delayed healing, and incontinence, so it is reserved for select cases or when other treatments have failed.

Video-assisted anal fistula treatment (VAAFT)

This minimally invasive technique uses a fistuloscope to view the fistula tract internally. The surgeon cauterizes and cleans the tract under direct vision and closes the internal opening. This allows precise treatment with minimal tissue damage and faster recovery.

Anal Fistula Prognosis

Anal fistula is not a life-threatening disorder, but it can significantly affect a patient's quality of life. Treatment emphasises destroying the fistula tract while preserving the sphincter complex. Complications of treatment can be life-altering for a patient and include faecal incontinence, fistula recurrence, and anal stenosis. The likelihood of recurrence ranges from 3% to 57%, depending on the anatomic classification of the fistula and the treatment modality.

Anal Fistula Treatment Cost in Hyderabad, India

The cost of Anal Fistula Treatment in Hyderabad generally ranges from ₹25,000 to ₹2,50,000 and above (approx. US $300 – US $3,010). The exact cost of anal fistula treatment depends on the type of fistula (simple vs. complex), the surgical procedure required, and whether there are any complications. Treatment typically involves surgical intervention such as fistulotomy, fistulectomy, or seton placement. The cost can vary based on the preoperative diagnostics (CT scan, MRI), hospital stay, surgical approach (open vs. minimally invasive), and postoperative care. Availability of cashless treatment options, TPA corporate tie-ups, and insurance assistance may further affect treatment expenses.

Cost Breakdown According to Type of Anal Fistula Treatment

• Initial Consultation and Non-Surgical Treatment (Medications & Sitz Baths) – ₹5,000 – ₹20,000 (US $60 – US $240)
• Fistulotomy (Simple Fistula Repair) – ₹25,000 – ₹70,000 (US $300 – US $840)
• Fistulectomy (Complete Fistula Removal) – ₹50,000 – ₹1,50,000 (US $600 – US $1,805)
• Seton Placement (For Complex Fistulas) – ₹60,000 – ₹1,20,000 (US $720 – US $1,445)
• LIFT Procedure (Ligation of Intersphincteric Fistula Tract) – ₹1,00,000 – ₹2,00,000 (US $1,205 – US $2,410)
• Advanced Fistula Treatment [Video-Assisted Anal Fistula Treatment (VAAFT), Laser, or Flap Surgery] – ₹1,50,000 – ₹2,50,000+ (US $1,805 – US $3,010+)

Frequently Asked Questions (FAQs) on Anal Fistula

What is an Anal Fistula?

An anal fistula is a small tunnel that develops between the inside of the anus or rectum and the skin near the anus opening. It usually happens after an infection causes a collection of pus called an abscess. When the abscess drains, a tunnel can remain, leading to ongoing drainage and discomfort. Anal fistulas usually cause pain and irritation and often require medical or surgical treatment to heal.

What causes an anal fistula?

The common cause of anal fistula is an infection of the small glands inside the anus. When the infection forms an abscess, it may not heal completely and leave behind a tract that opens onto the skin. Other causes may include Crohn's disease, TB, radiation injury, or trauma to the area. In some cases, fistulas may be linked to surgery, cancer, or chronic inflammation, though these are less frequent compared with simple infection-related cases.

What does an anal fistula look like?

Are anal fistulas contagious?

No, anal fistulas are not contagious. They do not spread from one person to another through contact, touch, or the sharing of items. The condition develops inside the body, after an internal infection, abscess, or inflammatory disease. Although bacteria are involved in the process, the fistula itself is not an infection that can be passed on. Treatment is focused on correcting the underlying problem and promoting healing, not on preventing transmission to others.

Can anal fistula cream help in the treatment of anal fistula?

Anal fistula creams, which contain antibiotics or anti-inflammatory agents, can help control symptoms such as pain, irritation, and mild infection around the external opening of a fistula. However, these creams do not usually treat an anal fistula because they cannot shut the internal tunnel that connects to the colon. They can provide short relief and promote hygiene.

What is the pathophysiology of an anal fistula?

An anal fistula starts with infection in small glands in the anus, causing an abscess. If the abscess drains but does not heal properly, a tunnel called a fistula forms between the infected gland inside the anus and the skin outside. This tunnel allows persistent drainage of pus or stool. Chronic inflammation and repeated infections keep the fistula open and difficult to heal naturally without treatment.

What are the different types of anal fistula?

Anal fistulas are classified based on their relationship to the anal sphincter muscles. The most common types include: -

Intersphincteric: The tract passes between the internal and external sphincter muscles.

Transsphincteric: The tract passes through both the internal and external sphincter muscles.

Suprasphincteric: The tract goes above the sphincter muscles.

Extrasphincteric: The tract passes outside the sphincter muscles, often originating from the rectum.

What is Anal Fistula Surgery Recovery?

Recovery from anal fistula surgery varies depending on the complexity, but it often takes 4 to 6 weeks for the wound to heal fully. Simple procedures usually result in discharge within 2-3 days, with pain and discomfort lasting 1-2 weeks. Proper wound care, hygiene, and follow-up are important steps to care anal fistula. Patients normally return to their normal activities within few days to weeks, depending on the surgery and individual healing. Complications like infection or bleeding may prolong recovery.

Can an anal fistula cause nausea?

An anal fistula produces local symptoms like discomfort, discharge, and swelling, but it can also cause nausea in some cases. Severe discomfort or pain from the fistula, especially when it is chronic or associated with an active infection and fever, can trigger a general feeling of unwellness, which may include nausea. However, nausea is not a direct or common symptom of an anal fistula itself.

Does a small anal fistula recur?

Yes, even small or simple anal fistulas can recur. Recurrence happens when the tract or internal opening is not completely treated or if there is any hidden branches are missed, especially in more complex anatomy. Overall recurrence rates after surgery vary widely but average around 15–20%, depending on the type of fistula and surgical technique used.

What is a superficial anal fistula?

Superficial anal fistulas are the simplest type of anal fistula. They involve a tract that passes only through the skin and a very minimal portion, if any, of the external anal sphincter muscle. Because they do not involve significant muscle, they are generally easier to treat with a high success rate and a very low risk of affecting bowel control.

Is an anal fistula a serious condition?

An anal fistula is not usually life-threatening, but it can become serious if not treated properly. It may cause continuous infection, pain, and discomfort, affecting daily life. In some cases, an untreated anal fistula can lead to repeated abscess formation or complications like incontinence.

When can normal bowel movements resume after surgery?

Normal bowel movements can be resumed within a few days after anal fistula surgery. This may depend on the individual and the type of procedure. Doctors advices a diet high in fibres, stool softeners, and adequate fluid intake to make bowel movements easier and less painful. Mild discomfort may be present initially, but it improves as healing progresses.

What happens if an anal fistula is left untreated?

If an anal fistula is treated promptly, it can lead to repeated infections and the formation of painful abscesses. Continuous discharge, swelling, and discomfort may persist and worsen over time. In some cases, the fistula can become more complex, making treatment more difficult.

Is anal fistula surgery painful?

No, anal fistula surgery is done under anesthesia, patients do not feel anything during the process. Pain or discomfort is typical after surgery, particularly in the first few days, but it may be controlled with medicine and good care. Pain eventually decreases as the wound heals.

Is Anal Fistula Treatment Covered by Insurance at PACE Hospitals?