At a glance
The anus is the external opening through which faeces is expelled from the body. Inside the anus, there are glands which produce mucus. If these glands become clogged, an abscess may develop. If the abscess is not drained or it is inadequately drained, a perianal fistula will develop.
A perianal fistula is a small tunnel that connects an abscess within the anus, to an opening on the skin around the anus. Fistula are further divided into simple or complex tracts. Simple tracks are easier to treat; however, complex tracts require long term management and are more difficult to eradicate.
There are many surgical procedures described and the outcomes and success of each vary. In theatre, an examination under anaesthesia is performed to further delineate between a simple or complex fistulous tract. The most commonly performed surgical procedure is the insertion of a seton. Other surgical options include cutting out the tract, plugs or clips. The pros and cons of each will be discussed preoperatively, and the best-suited procedure will be performed. After being diagnosed with a perianal fistula; you will be referred to Dr Maraj for an assessment. Further investigation such as an endoanal ultrasound or MRI may be performed to further categorised the track.
How to prepare for the procedure
If diagnosed with a perianal fistula; you will be referred to Dr Maraj for surgery. She will then instruct you on how to prepare for colorectal surgery. This usually involves emptying your colon with an enema or laxative and restricting your eating 6 hours before surgery. Surgery for perianal fistula is done in hospital, under a regional spinal block or general anaesthesia. You may need to stay in hospital overnight for observation.
What an anal fistula surgery involves
Due to the anal fistulas' proximity to the anal sphincter muscles, surgery is done very delicately to treat the fistula while protecting the anal sphincter muscles. Which type of colorectal surgery is advised will depend on the fistulous track as explained above.
For most perianal fistulas, a special drain called a seton will be placed to drain the fluid for the course of several weeks. Many studies have shown that the use of a Seton may result in healing of the fistula on its own.
For those fistulous tracks that do not heal with a Seton, a second surgery will be needed. This may be done through a fistulotomy as explained above, an advancement flap procedure or a lift procedure.
An advancement flap surgery involves the fistula being covered with a piece of tissue while the lift procedure is done by opening the skin above the fistula, spreading the sphincter muscles and tying the fistula off. In some cases, a collagen plug or a clip may be advised. This is done to seal up and heal a fistula as opposed to cutting the tract out. Biopsies may be taken intraoperatively to exclude infection or other causes of fistulae, including cancer or inflammatory bowel disease.
What to expect post-procedure
After any of the above types of procedures, you can expect some rectal and anal pain. You will be told how to care for your wounds. To ease the discomfort, a sitz bath may be suggested. Depending on the type of surgery performed, recovery time will vary.
You will be discharged on a regimen of stool softeners, analgesia, sits baths and dietary modifications.
While this is a simple guide and explanation of the procedure, Dr Maraj will be able to provide you with any further information should you need it.
Risks & complications
While complications are rare, guidelines and protocols are followed to prevent complications. The following are complications relating to fistula surgery: bleeding, infection, recurrence of the fistula or incontinence, pain and urinary retention. Dr Maraj will monitor you closely to ensure any complications are caught early and managed appropriately.
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