Overview of Anal Fistulotomy
An anal fistula, also known as anorectal fistula, is a common issue affecting the lower part of the digestive system in the U.S. This condition is essentially an infected tunnel that forms between the inside of the anus and the skin near it. This kind of problem usually comes about after an infection in the anal glands. These glands can get infected, creating pus-filled pockets known as abscesses. These abscesses can then either drain on their own externally or require surgical intervention to remove the pus. Sometimes, after the abscess drains away, a tunnel can remain that continues to drain or can get infected again.
Anal fistulas can also be associated with other conditions such as Hidradenitis suppurativa (a skin condition), trauma, cancer, tuberculosis, and Crohn disease, though these are considered atypical fistulas. To deal with the initial infection and pain, patients may need a surgical procedure done under anesthetics to drain the abscess. If the patient continues to have discharge from a punctum or small hole in the skin near the anus, doctors may suspect the presence of a fistula.
Fistulas can vary when it comes to their pathway in relation to the anal muscles. Some fistulas could be close to the surface (superficial) and simply require a surgical procedure called a fistulotomy to open them up, allowing them to heal. However, fistulas that are deeper and pass through more of the anal muscles can’t simply be opened up as it could lead to loss of bowel control. In these cases, surgeons may place a Seton, which is a kind of elastic band or strong thread, to gradually cut through the fistula over time. This method allows the deeper parts of the fistula to heal while reducing the risk of loss of bowel control. There are other options for treating persistent fistulas, such as by surgically creating a flap of tissue to close the fistula opening.
Patients with complex fistulas due to cancer or Crohn disease provide a unique challenge. Cancerous fistulas often require a team of healthcare professionals and can involve both chemotherapy and radiation treatment. They might also use a Seton to allow for drainage and prevent abscess from interfering with patient care. For patients with Crohn disease, Seton placement is typically the first step, followed by long-term medication to manage the disease and promote healing. Tuberculosis and Hidradenitis suppurativa can be treated with antibiotics, with Seton taken as a secondary measure to prevent abscess forming. In severe cases where the fistula condition is severe, a colostomy procedure might be needed in order to divert waste away from the colon and help control infections.
Anatomy and Physiology of Anal Fistulotomy
The anal sphincter is made up of two parts – the internal and the external anal sphincters. The external sphincter is a muscle that surrounds the anus and can be controlled consciously. On the other hand, the internal sphincter is located closer to the inside of the anus and works automatically without our conscious control.
There are four main types of anorectal fistulas, which are abnormal connections between an organ and another structure.
- The most common type, known as intersphincteric, is found between the two sphincter muscles and has an opening close to the anus.
- The trans-sphincteric fistula goes through the external sphincter and has its opening a bit further away from the anus, usually associated with a specific type of abscess.
- The suprasphincteric fistula goes above a muscle known as the puborectalis and tracks sideways near another muscle group.
- The rarest type of fistula, called extrasphincteric, goes through a space in the pelvic area, a muscle group, and then into the wall of the rectum.
These fistulas usually grow from abscesses, which are painful, swollen areas filled with pus. Often, the internal opening of the fistula is found at the dentate line, which is inside the anal canal. Diagnosing the type of fistula typically involves an examination under anesthesia, sometimes using a tool called an anoscope or a flexible sigmoidoscope.
It’s crucial to figure out which structures are involved in the fistula connection. You can only cut a small amount of the external sphincter muscle – up to 30% of it – without risking a loss of bowel control. If there’s risk of cutting too much of the sphincter or to ensure pus drains adequately, a special thread called a ‘Seton’ can be placed through the fistula. A Seton can either help the sphincter to gradually separate over time, or it can allow an abscess to heal slowly around it.
A rule of thumb called Goodsall’s rule is usually followed to locate the origin of the fistula. According to this, if an imaginary line is drawn across the anus, a fistula opening that is in front of this line will usually be found internally within 3 cm of the anal opening and will directly lead into the anal canal. Contrarily, if the opening is behind this line or outside of the 3 to 4 cm area from the anal opening, then these fistulas usually curve around to a certain gland in the middle of the back of the anus. However, this rule may not always hold true and there may be exceptions.
Why do People Need Anal Fistulotomy
Typically, people who come in with a perianal fistula, or a small tunnel-like hole between the skin and the inside of the anus, have had a history of an abscess, or a collection of pus, in the same area. This abscess could have been drained by a doctor or it may have drained on its own. Evidence of this is chronic, or long-lasting, drainage that persists for weeks to months. This area could suddenly start hurting more and have an increase in drainage. When this happens, they come to the doctor with this ongoing issue.
Doctors usually diagnose this condition based on the patient’s history and a physical exam. This procedure is optional and often conducted under anesthesia. The doctor could either perform a fistulotomy, a procedure to open and drain the fistula, or they might place a “Seton,” a piece of thread left in the fistula to help it heal.
It’s essential for the doctor to know beforehand if the patient or their family has a history of Crohn’s disease, a type of bowel disease, and/or any symptoms of fecal incontinence, or difficulty controlling bowel movements. In patients with Crohn’s disease and in female patients with a front-sided fistula, a non-cutting Seton placement is preferred over a fistulotomy. A Seton would also be a safer option if the doctor is unsure about how deep the fistula goes.
When a Person Should Avoid Anal Fistulotomy
Sometimes, there are a few reasons why a medical tool called a Seton cannot be placed in your body. One reason is if you have an active infection or abscess. In such cases, doctors would generally clear up the infection or drain the abscess first. If they identify a pathway, or tract, during this procedure, they can also put in a Seton. However, if they find cancer at the internal opening of the tract, they would need to treat you for cancer, which requires further tests and management.
This Seton can be used to treat both new and old tracts, no matter the associated health conditions. If the tract is superficial or close to the surface and is located in the posterior area involving a small amount of muscle that helps control bowel movements (sphincter muscle), the best approach is usually a simple procedure called a fistulotomy.
However, for other groups of patients, like women, those who previously had issues controlling their bowel movements, or those suffering from Crohn’s disease (an inflammatory bowel condition), fistulotomy isn’t recommended because they risk losing control of their bowel movements. Instead, after the Seton is placed, it is advisable for these patients to have follow-up appointments with colorectal specialists for more advanced surgical treatments.
Equipment used for Anal Fistulotomy
The procedure is usually carried out in a surgery room, with the patient either asleep (under general anesthesia) or significantly relaxed and not feeling pain (through adequate sedation). The patient could be positioned face down (prone) or with legs raised and knees bent (lithotomy position) depending on where the surgeon expects to find the problem area, either at the front or back of the opening of the digestive tract (anus).
The surgeons need a tool to widen the anal opening (an anal retractor). For something called a Seton, which helps treat a special kind of abscess, a loop for closing off blood vessels, strong nylon thread, or a rubber band might be used. To find the tract, which is a pathway that has abnormally developed, the surgeon might use a long thin tool to probe (anal probe, like a lacrimal duct probe), and might also need a small 10 cc syringe filled with a bubbling solution (hydrogen peroxide) with a small tube (angiocatheter) attached to it to inject into the tract.
To make the patient more comfortable after operation, the surgeon might inject a local painkiller (analgesia). At the end of the procedure, a dressing is applied to the surgical area (perineum) to help manage any fluid that may come out after surgery.
Who is needed to perform Anal Fistulotomy?
The treatment is typically done with a doctor and a helper. The helper holds a special tool called an anal retractor. This tool helps them see the inside part that needs to be treated and keeps the healing device, called a Seton, in place while it’s being tied together. The doctor and his helper work together to make sure everything goes smoothly.
Preparing for Anal Fistulotomy
The Seton procedure requires hardly any preparation from the patient’s end. Some doctors might suggest having an enema in the morning before the procedure to make sure the bowels are empty. The rest of the preparation is done in the operating room, like positioning the patient and ensuring all the necessary equipment, including the Seton material, is on hand. Doctors might also consider giving patients antibiotics before the procedure to protect against certain types of bacteria.
How is Anal Fistulotomy performed
A fistulotomy is a surgical procedure typically performed to treat an anal fistula, which is an abnormal tunnel between the inside of the anus and the skin around it. This procedure is typically performed in an operating room with the patient under sedation, though some surgeons might choose to use general anesthesia, which means the patient will be completely unconscious.
The procedure starts with the patient being placed in the appropriate position – either facedown (prone) or on their back with their legs raised and spread apart (lithotomy). The choice of position is decided based on the location of fistula; if it’s towards the front of the anus (anterior), a prone position is preferred. However, if it’s towards the back (posterior), the lithotomy position would be more suitable. This allows the surgeon to clearly visualize the opening of the fistula and gain better access to it.
The surgeon then uses a small tool known as a fistula probe to explore the fistula and figure out its path. Usually, long-standing fistulas can be traced easily. But if the fistula is challenging to identify, a solution of hydrogen peroxide may be gently injected into its external opening. This solution causes visible bubbling at the internal opening of the fistula, marking its location.
Once the fistula’s path is identified, the surgeon will guide a special type of thread (called a Seton) through it. This thread is then tied in a secure loop to prevent it from slipping out. Over time, the surgeon might slowly tighten this loop if it’s a cutting type of Seton. Alternatively, if it’s a non-cutting type, the loop will be left loosely fitted. It is vital not to force a path if the tract cannot be identified, to avoid creating a false tract.
If the fistula cannot be found during the procedure, the surgeon will make a small opening near the anal entrance and plan for a re-examination under anesthesia in the following weeks. In some cases, a CT scan or an MRI of the pelvis might be taken to help identify the tract. After the surgery, local anesthesia might be used to manage the pain, and a special dressing is applied to the operated area.
Finally, the surgeon will carefully document observations, such as the depth of the tract, the location of internal and external openings, and plans related to the Seton, for accurate follow-up care.
Possible Complications of Anal Fistulotomy
This medical procedure could potentially have some difficulties. Specifically, there might be issues finding and draining an abscess (a swollen area within body tissue that contains an accumulation of pus) or identifying the fistula tract (an abnormal connection between two body parts). There is also a risk of creating an incorrect fistula tract. With the Seton (a surgical thread passed through a fistula), there could be a small amount of stool leakage, and patients should be taught how to clean this properly.
Minor bleeding from the affected area may occur, but this should not be serious. While infections are not common, they can happen, and should be taken care of right away. If an infection ensues, it could mean a patient may need another examination under anesthesia, oral antibiotics if it is not that severe, or strong intravenous (IV) antibiotics and further examination if the infection is severe, such as a flesh-eating infection in the perineal area (the region between the thighs).
Incontinence (the inability to control urination or defecation) is very rare with the Seton placement. If the internal opening is not properly identified during the procedure, the fistula may come back, potentially in a more complicated form.
What Else Should I Know About Anal Fistulotomy?
If you have a fistula, which is an abnormal connection between two body parts, near your anus, it usually means you had an abscess, or a collection of pus, in the same area before. This abscess could have drained out naturally, or you might have had it surgically cleaned. However, if there wasn’t a previous abscess, the fistula could be a symptom of Crohn’s disease, a long-term condition causing inflammation of the lining of the digestive system, hidradenitis suppurativa, a skin condition causing small, painful lumps to form, or even cancer in the region between the genitals and the anus.
Women who have had a baby may get a fistula at the front of the anus. In this case, you should expect a procedure where a string (Seton) is threaded through the fistula. This helps to drain out the fluid and allows the fistula to heal.
Basic fistulas can be treated by general surgeons, but if the fistula is more complicated, it’s better to see a specialist surgeon who deals with diseases of the colon and rectum.
