Anal Fissure and Lateral Sphincterotomy and Anal Fistula

CHAPTER 96 Anal Fissure and Lateral Sphincterotomy and Anal Fistula



James A. Surrell



Anal Fissure


Anal fissure is defined as a painful linear ulcer (tear) of the distal anal canal, located just inside the anal opening and extending cephalad toward the dentate line (Fig. 96-1). The most common cause of an anal fissure is from passing a large, firm, forced bowel movement. The history of a patient with anal fissure is so characteristic that the diagnosis can usually be made accurately based on the history alone. Patients complain of moderate to severe pain during and after bowel movements and have a variable amount of bleeding. The painful symptoms nearly always resolve within 15 to 30 minutes. Rarely, the patient with an anal fissure complains of severe and constant pain, but this is usually seen only with a severe, deep anal fissure with associated significant anal spasm. A small amount of bleeding with bowel movements is common (“just on the toilet paper”), with frank bleeding rare.



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Figure 96-1 Anal fissures. Patient is in the left lateral decubitus position. A, External examination. Gentle eversion of the buttocks reveals a posterior midline anal fissure. B, Anoscopic examination. Chronic posterior anal fissure with a distal “sentinel pile/tag” and a proximal hypertrophic anal papilla at the level of the dentate line. C, Superficial anal fissure visualized easily with manual retraction of perianal tissues. D, Acute anal fissure diagnosed with use of an Ives slotted anoscope. E, Chronic anal fissure. Arrows point to sentinel tag (a), fissure (b), and anal polyp (c). F, Large acute anal fissure obscured by hemorrhoids until fold retracted with cotton-tipped applicator.


(C–F, Courtesy of John L. Pfenninger, MD, The Medical Procedures Center, PC, Midland, Mich.)


The severe pain, “like glass is cutting me,” is thought to be secondary to tearing the fissure open and associated internal anal sphincter spasm. Subsequently, avoiding constipation and keeping the bowel movements soft along with relieving the anal muscle spasm is the goal of all therapies.


The internal anal sphincter is a totally involuntary muscle and responds to pain by contracting, which leads to more pain and a smaller opening through which the stool must pass, thus creating a vicious cycle. The external sphincter generally acts in an involuntary fashion but is under voluntary control. Both sphincters form a ring of muscle around the anus (Fig. 96-2).


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Figure 96-2 Sagittal section of the anal canal to illustrate the palpation of the intersphincteric groove by the surgeon’s examining finger. (Also see Chapter 97, Clinical Anorectal Anatomy and Digital Examination.)


The history must include whether the fissure is acute or chronic. Chronic fissure can arbitrarily be defined as one that has been present with signs and symptoms of pain or bleeding for more than 3 months. Unless the symptoms are extremely disabling, all fissures should be given a trial of conservative management, as discussed later. If conservative management fails, lateral internal sphincterotomy is the procedure of choice for treatment of an anal fissure.


Once the history suggests an anal fissure, the diagnosis can usually be made easily on visual examination of the external anus and with gentle digital examination. The left lateral decubitus position is recommended for patients undergoing anorectal examination. With gentle eversion of the anoderm, one can usually directly visualize the fissure. Touching the fissure with a cotton-tipped applicator confirms the diagnosis if this reproduces the painful symptoms experienced with bowel movements. If necessary, a digital examination with good lubrication will confirm not only pain but marked increased sphincter tone due to spasm. Finally, if the diagnosis is in doubt, the anoscopic examination can provide more direct visualization. In classic cases, the insertion of the anoscope may be so painful that it should be deferred. It should be performed at a later time to identify other possible diseases.


Anal fissures occur most commonly in the posterior midline. Approximately 90% of fissures are in this location, and 10% are located in the anterior midline. If the clinician sees an anal fissure in any location other than the anterior or posterior midline, a thorough gastrointestinal work-up is necessary to rule out the presence of inflammatory bowel disease (IBD) or other very rare causes such as tuberculosis, syphilis, occult abscess, leukemic infiltrates, carcinomas, herpes, or acquired immunodeficiency syndrome.


If it is present, IBD with an atypical fissure is most commonly Crohn’s disease. Another physical examination feature that should raise the suspicion of perianal Crohn’s disease is the presence of fleshy, edematous skin tags (see Chapter 108, Removal of Perianal Skin Tags [External Hemorrhoidal Skin Tags]). If the examiner suspects IBD, upper gastrointestinal with small bowel x-ray films are necessary, as well as colonoscopy or barium enema radiography combined with flexible sigmoidoscopy. Magnetic resonance imaging enterography also may be used to evaluate for Crohn’s disease and other bowel lesions.



Treatment


If the patient has symptoms of moderate to severe pain or bleeding during and after bowel movements, he or she probably has an anal fissure. As noted, the initial goal of therapy is to keep the bowel movements soft and easy to pass while providing pain relief. If these symptoms are severe, disabling, and constant, surgical intervention should be considered sooner rather than later.


However, for most fissures, a 1- to 3-month trial of conservative management is indicated. This management includes a high-fiber diet of at least 30 g of dietary fiber, six to eight glasses of water, and 3 to 6 g of commercially available fiber supplements per day. If the fissure pain is severe, consider prescribing 5% lidocaine ointment to be applied to the fissure on arising and at bedtime, as needed throughout the day, and again after bowel movements. Commercially available nonprescription ointments and creams are minimally effective in the treatment of anal fissures. They may, however, be used to lubricate the anal canal for bowel movements. Steroid preparations may or may not be helpful, but they are not intended for long-term use.


Specifically advise patients not to use any ointment or cream with a rectal tube-tipped applicator or any suppositories because these products and devices tend to worsen the symptoms of an anal fissure. Advise patients to apply a small amount of any recommended ointment or cream directly to the fissure with a finger because an anal fissure is always located just inside the anal verge. The application of silver nitrate to or the use of electrocautery on the fissure site is not recommended and may even exacerbate the symptoms. Anal dilators should not be used because of the unpredictable disruption of the anal sphincters and the potential for causing incontinence.


For persistent fissures, a trial of 0.2% to 0.5% nitroglycerin ointment or jelly may be tried. It is recommended that a small amount of this ointment (about the size of a pencil eraser) be applied directly to the fissure three to four times a day, and that it be gently rubbed onto the fissure and not just applied superficially. Patients must be cautioned that if they experience a headache, they are using too much nitroglycerin ointment. Usually, using a lesser amount will eliminate the headaches. The 0.2% to 0.5% nitroglycerin ointment formulation is not yet commercially available (it comes as 2%), but it can be made up by any reputable local pharmacist from a physician’s prescription. The prescription usually reads as follows: “Rx: 0.2% nitroglycerin ointment, DISP: 60 g, SIG: apply small amount to anal fissure, as directed, three to four times a day for 6 to 8 weeks for anal fissure pain.” (Be sure to clarify 0.2%, not 2.0%.) Most studies use soft white paraffin to dilute it, or lidocaine or Anusol ointment. If headache does occur, the patient should take an aspirin 1 hour beforehand and lessen the volume applied to the fissure.


Some practitioners now question the efficacy of nitroglycerin and have switched to using nifedipine gel 0.2%. The mixture is rubbed in two to three times a day. (Nifedipine gel 0.2%. Mix #10, 20-mg capsules of nifedipine in 100 mL surgical lubricant. Apply to rectal area qid [100 mL].) Some add bethanechol to make 0.1%. K-Y Jelly or 2% lidocaine jelly can be used instead of surgical lubricant.


Both medications pharmacologically relax the anal sphincter to reduce spasm and pain and to assist with the healing process (a “chemical sphincterotomy”).


Botulinum toxin (Botox) injected into the anal sphincter is also an option for medical management of anal fissures. The mechanism of action appears to be inhibition of anal sphincter spasm. Initial response is favorable, but long-term follow-up in some studies shows a high recurrence rate. Botox is contraindicated in pregnant and nursing patients and those with neuromuscular disease.



Botulinum Toxin Type A Injection Technique


Botulinum toxin type A (Botox) is generally available in 100-U aliquots. (See storage and mixing instructions, Chapter 56, Botulinum Toxin.) The dosage most commonly used for anal fissures is a total of 40 U, with half injected on the right and the remainder injected into the left lateral side of the anal verge. (Remember, most “routine” anal fissures are located anteriorly and posteriorly.) Although various techniques are used, the best results are apparent when the Botox is injected away from the fissure. Usual and customary sterile technique is used, and the perianal area is prepared with povidone–iodine (Betadine). A local anesthetic injection is not recommended because this will likely cause a similar amount of discomfort as the Botox injection itself. This procedure may be done with or without an anoscope. If the patient is not in too much pain from the anal fissure, a small and well-lubricated anoscope is gently placed into the anal canal in the usual fashion. It is recommended that an open-sided anoscope (Ives slotted anoscope) be used to facilitate palpation of the intersphincteric groove on the right and left sides (see Fig. 96-2). This will obviously require withdrawal and replacement of the anoscope to identify the intersphincteric groove on the contralateral side and may cause significant pain. Each side needs to be injected. The specific technique is to inject a total of 20 U of Botox into the intersphincteric groove using a 30-gauge needle at a depth of approximately 1 cm. (Some choose to inject directly into the internal sphincter.) The two sites of injection are in the middle of both the right and left perianal tissues, directly into the intersphincteric groove. The intersphincteric groove is palpable and usually easily identified on digital examination by slowly withdrawing the gloved examining finger from just within the anal canal out onto the perianal area. In this manner, one should be able to identify this palpable groove without difficulty. It is important to accurately identify the intersphincteric groove site for the subsequent Botox injection into the intersphincteric space.


The effect of botulinum toxin (relaxing the internal sphincter) is not permanent and lasts only 2 to 4 months. If the patient also follows a high-fiber diet, however, this is usually enough time for the fissure to heal. If there is relief but the fissure persists, a second injection can be tried. If there is little relief, a second injection can be made with a smaller dosage of toxin 4 to 6 weeks after the first.


Mild, transient incontinence of gas or feces is not uncommon with this treatment.



Lateral Internal Sphincterotomy



Indications


Lateral internal sphincterotomy is indicated if conservative management has been recommended, the patient has complied for approximately 1 month, and the symptoms of pain or bleeding are still present during and after bowel movements, without improvement.



Contraindications



• An atypical location of the fissure (other than anterior or posterior) until a work-up for secondary causes is completed (see previous discussion)

• Preexisting anal incontinence, although the coexistence of an anal fissure and incontinence is uncommon


Equipment


The only special equipment required for lateral internal sphincterotomy is an assortment of various-sized anoscopes and a surgical electrocautery unit. The Hill-Ferguson anal retractor is available in small, medium, and large sizes. Any modern electrosurgery device with a cutting and coagulation setting should suffice.



Preprocedure Patient Preparation


Although some will perform lateral sphincterotomies in the office, most procedures are performed in day surgery. They take approximately 15 minutes and can be performed in either the left lateral decubitus knee–chest position or in the dorsal lithotomy (pelvic) position.


Inform the patient that lateral internal sphincterotomy is a procedure to divide only the fibers of the involuntary internal sphincter to allow the anal canal to relax during bowel movements. The external sphincter remains intact and allows for anal control. There is an approximate 5% recurrence rate and a 3% to 5% infection rate. Patients should expect mild to moderate postprocedure pain, which usually is well controlled with oral analgesics. Generally no more than 1 or 2 days is required for recovery, and postoperative pain is minimal compared with the preoperative discomfort from the fissure. There will be minimal bleeding and spotting for up to 6 weeks after the procedure. With proper technique combined with a thorough understanding of anal sphincter anatomy, alteration of anal continence is uncommon.


As always, before any surgical procedure patients should be made aware of nonoperative treatment options, as discussed previously. If the fissure is not resolved with either conservative or surgical treatment, the patient generally experiences intermittent, persistent symptoms. Fibrosis of the internal anal sphincter can lead to anal stenosis. A subcutaneous fistula originating through the base of a long-standing anal fissure may develop, but is not common.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Anal Fissure and Lateral Sphincterotomy and Anal Fistula

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