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Lateral Internal Sphincterotomy: Before Your Surgery

What is lateral internal sphincterotomy?

Anal fistula

Lateral internal sphincterotomy is a type of surgery. It helps heal an anal fissure that hasn't improved with other treatments. An anal fissure is a tear in your anus.

You may be asleep during surgery. Or you may be awake. If you are awake, you will get medicine to help you relax. To do the surgery, the doctor puts a lighted tube into the anus. This is called a scope. It lets the doctor see the inside of the anus. Then the doctor puts special tools through the scope. They are used to make a cut (incision) in the ring of muscle that controls the anus. This ring of muscle is called your internal anal sphincter.

The surgery usually takes less than 30 minutes. Most people go home the same day.

For many people, the pain from their anal fissure goes away within several days. You will probably be able to go back to work and your usual activities in about 1 to 2 weeks. But it could take 6 weeks to completely heal.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

What happens before surgery?

Surgery can be stressful. This information will help you understand what you can expect. And it will help you safely prepare for surgery.

Preparing for surgery

  • Understand exactly what surgery is planned, along with the risks, benefits, and other options.
  • Tell your doctors ALL the medicines, vitamins, supplements, and herbal remedies you take. Some of these can increase the risk of bleeding or interact with anesthesia.
  • If you take blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin, be sure to talk to your doctor. He or she will tell you if you should stop taking these medicines before your surgery. Make sure that you understand exactly what your doctor wants you to do.
  • Your doctor will tell you which medicines to take or stop before your surgery. You may need to stop taking certain medicines a week or more before surgery. So talk to your doctor as soon as you can.
  • If you have an advance directive, let your doctor know. It may include a living will and a durable power of attorney for health care. Bring a copy to the hospital. If you don't have one, you may want to prepare one. It lets your doctor and loved ones know your health care wishes. Doctors advise that everyone prepare these papers before any type of surgery or procedure.

What happens on the day of surgery?

  • Follow the instructions exactly about when to stop eating and drinking. If you don't, your surgery may be canceled. If your doctor told you to take your medicines on the day of surgery, take them with only a sip of water.
  • Take a bath or shower before you come in for your surgery. Do not apply lotions, perfumes, deodorants, or nail polish.
  • Do not shave the surgical site yourself.
  • Take off all jewelry and piercings. And take out contact lenses, if you wear them.
  • You may need to empty your colon with an enema or laxative. Your doctor will tell you how to do this.

At the hospital or surgery center

  • Bring a picture ID.
  • The area for surgery is often marked to make sure there are no errors.
  • You will be kept comfortable and safe by your anesthesia provider. The anesthesia may make you sleep. Or it may just numb the area being worked on.
  • The surgery will take about 30 minutes.

Going home

  • Be sure you have someone to drive you home. Anesthesia and pain medicine make it unsafe for you to drive.
  • You will be given more specific instructions about recovering from your surgery. They will cover things like diet, wound care, follow-up care, driving, and getting back to your normal routine.

When should you call your doctor?

  • You have questions or concerns.
  • You don't understand how to prepare for your surgery.
  • You become ill before the surgery (such as fever, flu, or a cold).
  • You need to reschedule or have changed your mind about having the surgery.

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Care instructions adapted under license by Kaiser Permanente. This care instruction is for use with your licensed healthcare professional. If you have questions about a medical condition or this instruction, always ask your healthcare professional. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.


The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.

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