Pediatric Surgery for Anal Fissure 

Updated: Jul 05, 2018
Author: Brian P Gillett, MD; Chief Editor: Philip Glick, MD, MBA 

Overview

Background

An anal fissure is a tear of the squamous epithelial mucosa of the anal canal, between the anocutaneous junction and the dentate line.[1] They most commonly occur during passage of a firm stool. Anal fissures are common in infancy, and they represent the most common cause of bright rectal bleeding at any age.

An anal fissure, though ostensibly a minor problem, may lead to years of discomfort if diagnosis and treatment are not carried out in a timely fashion. If these small tears (and the occasionally associated superficial infection) are not promptly diagnosed and treated, they can cause severe anorectal pain during bowel movements and set in motion a cycle of stool negativism, constipation, and increasing pain with subsequent defecation.

Too often, this seemingly minor problem remains underappreciated or unnoticed by clinicians. However, when considered, the diagnosis is rather simple to make, and the treatment is usually quite effective.

Pathophysiology

The underlying pathophysiology of anal fissures is fairly complex. It is likely to be multifactorial and may involve anodermal ischemia, infection, chronic constipation, and hypertonicity of the smooth muscle of the internal anal sphincter and its elevated resting pressure.

Fissures have a predilection for the posterior midline (90%) but may also be located in the anterior midline or laterally. The explanation for this phenomenon is both anatomic and functional. The posterior commissure of the anoderm is less well perfused than other anodermal regions. Furthermore, before the branches of the inferior rectal artery reach the anoderm, they course perpendicularly through septa of the internal anal sphincter. Thus, flow through these arterioles is threatened by elevated intramuscular pressure of the internal anal sphincter.

Many studies have demonstrated that adult patients with anal fissures have significantly elevated anal canal pressures that exceed the intraluminal pressure of arterioles. Therefore, increased tone at the internal anal sphincter compromises perfusion of the anoderm, particularly at the posterior midline, by compressing arterioles of the inferior rectal artery. High canal pressures likely result in increased anodermal ischemia that prevents small mechanical tears from healing in a timely fashion; the tears then progress to clinically significant anal fissures.

A similar pathophysiology is speculated to be the etiology of anal fissures in infants and children.

Etiology

The generally accepted proximate cause of the anal fissure is a mechanical tear resulting from the passage of hard stool. An unhealed fissure may become infected and develop into a chronic ulcer. A healed fissure may develop into a classic sentinel skin tag in the posterior midline.

Epidemiology

Most fissures affecting the pediatric population manifest in children aged 6-24 months; however, the overall incidence of the problem is not well described.

Prognosis

In several small studies, chemical sphincterotomy using glyceryl-trinitrate (GTN) with adjunctive stool softeners was shown to be quite effective at relieving symptoms and promoting healing. However, most pediatric surgeons report equal success with open or closed lateral sphincterotomy for acute and chronic anal fissures.

Recurrence rates of open or closed lateral sphincterotomy have been reported to be 0-10%, with most of the recurrences occurring in adults and with chronic fissures. In contrast, anal dilatations have the highest rates of fistula recurrence (10-30%) and, for this reason, are not recommended in children.

Large prospective series describing outcome in patients following surgical intervention for chronic anal fissure also are lacking in the literature. However, most authors report that anal dilatation and lateral subcutaneous sphincterotomy are both effective therapeutic interventions for chronic anal fissures.

Patient Education

Patients and their families are educated about urinary retention, severe perianal pain, sepsis, bleeding, and transient fecal incontinence.

For patient education resources, see the Digestive Disorders Center, as well as Anal Abscess, Abdominal Pain in Children, and Rectal Bleeding.

 

Presentation

History

The diagnosis is usually made through a careful history and physical examination. A history of constipation is often elicited. The child may cry with bowel movements, and streaks of bright red blood on the surface of hard stool, on the diaper, or on the toilet paper after a bowel movement may be identified by the patient or family.

It is important to remember that underlying systemic illness frequently manifests with anal lesions. Thus, pertinent negatives, such as fever, rash, oral or skin lesions, weight loss, diarrhea, and abdominal pain, should be excluded. Also, psychological problems and stressors that may provoke stool negativism should be elicited.

Physical Examination

The diagnosis is established by inspecting the anal region. For this examination, the parents should hold the child's hips in acute flexion while the examiner separates the buttocks, retracting the perianal skin folds. For older children, the anoderm may be spread apart while the child bears down because this maneuver facilitates visualizing the fissure.

If a fissure is identified, a digital examination is best avoided because it is likely to elicit unnecessary pain and sphincter spasm. However, if a fissure is not observed, a digital examination should be performed to rule out other pathology. If the examination is limited by pain and the diagnosis remains unclear, an examination under anesthesia should be pursued.

The fissure appears as a minor laceration, usually in the midline, and is more often posterior than anterior. If the fissure is chronic, a small external skin tag (ie, sentinel tag) may be identified at the base of the laceration; this represents epithelialized granulomatous tissue secondary to chronic inflammation.

If a fissure is suspected, palpation of the abdomen is essential to check for palpable masses (stool) in the left lower quadrant.

 

DDx

Diagnostic Considerations

The differential diagnosis includes the following:

  • Pruritus ani
  • Inflammatory bowel disease (IBD)
  • Tuberculosis
  • Inherited disorders of the immune system
  • AIDS
  • Chlamydia
  • Gonorrhea
  • Neoplasm

Also, sexual abuse should always be considered in the differential when evaluating patients with anal or genital complaints.

Most anal fissures are single in number and occur at the posterior midline. Multiple fissures of the anal canal, lateral fissures, or those that extend proximal to the dentate line should raise the suspicion of a more serious underlying disease process. Lateral fissures should raise the possibility of trauma, infection, neoplasm, AIDS, syphilis, tuberculosis, or IBD.

 

Workup

Approach Considerations

Laboratory and imaging studies are not routinely necessary in the workup of an anal fissure. However, if the clinician suspects the presence of an underlying disease process, additional tests are indicated, such as serology, purified protein derivative of tuberculin (PPD), stool cultures, biopsy, or further gastrointestinal workup. An abdominal flat radiograph to check for constipation is often illustrative and serves as a baseline examination before administration of stool softeners is initiated.

 

Treatment

Approach Considerations

Surgical intervention is rarely required for acute fissures in children, and symptoms from an acute fissure often resolve within 10-14 days of conservative medical management. However, if an anal fissure does not heal after 6-8 weeks of medical therapy and the diagnosis is not in question, surgery may be indicated.

Relative contraindications to operative treatment of anal fissure include inflammatory bowel disease (IBD) and profound immunosuppression (ie, absolute neutrophil counts < 100/μL; see the Absolute Neutrophil Count calculator).

Treatment of anal fissures has advanced significantly over the past decades. Local reconstruction with advancement flaps has been described as an effective adjunct to chronic fissure excision. Reversible chemical sphincterotomy is a promising development in the treatment of acute (and possibly chronic) anal fissures.

Medical Therapy

Acute fissures usually improve with conservative management, which includes dietary modification, stool softeners, and sitz baths. Increasing the patient's fluid consumption and fiber intake may be sufficient. If a stool softener is used, it should be carefully titrated to avoid the development of diarrhea and dehydration. The stool softener of choice is an osmotic agent that causes water to be retained with the stool (eg, polyethylene glycol), and the dosage is titrated for the patient's size. It is available as a powder that is mixed with 8 oz of water before administration.

Although 10-14 days of conservative medical management is often sufficient for resolution of acute fissure symptoms, as long as 6-8 weeks may be necessary for the actual tear to heal. After 6-8 weeks, the fissure is considered chronic, and more active measures (eg, chemical or surgical sphincterotomy) may be considered. Although studies validating the use of chemical sphincterotomy in the pediatric population remain limited, the available literature appears promising.[2]

Glyceryl-trinitrate (GTN) is the most widely used agent for chemical sphincterotomy.[3, 4, 5, 6] GTN 0.2% ointment is applied topically to the lower anal canal two or three times daily until the fissure heals. Although the safety of GTN therapy in this setting is well established, poor compliance due to GTN-induced headaches can be a barrier to its use (see Complications).[7]

Topical diltiazem (available as an extemporaneously prepared 2% gel) may be a potential alternative to GTN that has fewer adverse effects; however, additional evidence is required before recommendations regarding the use of this agent can be made. Topical diltiazem therapy appears to be more effective than oral diltiazem therapy, with fewer adverse effects.[8, 9]

Topical nifedipine with lidocaine has also been employed and appears to be safe and effective, with a low recurrence rate.[10]

Botulinum toxin injections reduce internal anal sphincter tonicity by inhibiting the release of acetylcholine into the synaptic gap. This therapeutic option appears to be more effective than isosorbide dinitrate (ISDN) ointment for the primary treatment of chronic anal fissures in the adult population, with fewer adverse effects.[11] However, dosing, ideal site(s) of administration, and experience with this drug are lacking in the pediatric population. Botulinum toxin may be used for multiple, wide-based, and nonhealing fissures.

Surgical Therapy

As noted, surgical treatment is rarely needed for most infants and children with an acute anal fissure. Some fissures may take as long as 8 weeks to resolve with conservative management. It is important to keep in mind that if the fissure has not healed following medical therapy, the diagnosis may be in question, and an examination under anesthesia is warranted. If the fissure persists despite medical management, the operative procedure in children and infants is an open lateral internal sphincterotomy.[12]

Excision of a chronic ulcer may be warranted in addition to the sphincterotomy. All excised tissue should be evaluated by a pathologist. Because any associated anal stenosis is relieved successfully with the sphincterotomy, advancement flaps to treat the associated refractory stenosis typically are not needed.

Operative details

Treatment of children with anal fissures is slightly different from treatment of adults in that an outpatient open lateral internal sphincterotomy is the procedure of choice. This relieves the spasm and, ultimately, the vicious circle that characterizes the constellation of symptoms ascribed to anal fissure. Anal dilatation to treat anal fissure has been abandoned because of the 30-40% rate of recurrence.

In addition, if the history and physical examination reveal a lifelong history of constipation or failure to pass stool in the first 48 hours of life, an ectopically placed anus and Hirschsprung disease must be considered in the differential diagnosis, and a careful rectal evaluation and rectal biopsy should be performed with the same anesthetic.

Open lateral internal sphincterotomy is performed with the patient in the lithotomy position under a light anesthetic administered via a laryngeal mask. The intersphincteric groove is palpated, and the submucosa is injected with 0.25% bupivacaine with 1:200,000 epinephrine.

A 1-cm curvilinear incision is made overlying the intersphincteric groove. The internal sphincter is medial to the external sphincter and lateral to the submucosa of the anus. The sphincter is identified and elevated, and an electrocautery device is used to divide a segment as far proximal as the fissure itself. The overlying incision is closed.

Closed lateral sphincterotomy is also advocated in children. The knife blade is positioned in much the same manner as in an open sphincterotomy, but the difference is that the knife is inserted in the intersphincteric groove, rotated 90°, and advanced toward the anal mucosa. Hemostasis is achieved by means of direct pressure, and this puncture wound is not closed.

Chronic anal fissures should be treated with excision of the fissure along with its sentinel tag (pile) and internal sphincterotomy at the base of the ulcer. The wound is left open and should heal in 7-14 days without scarring. Compulsive wound care, consisting of washing the area with soap and water after each bowel movement, is essential for a successful outcome.

Complications

Headache and diarrhea are the most common complications of administering topical nitrates and stool softeners, respectively. Significant hypotension with topical nitrate administration has not been reported in the literature. However, during the first office visit, children and their families should be questioned about a history of vascular headaches, and blood pressure should be taken before the initial application of topical nitrates. Incontinence has not been associated with these therapeutic regimens.

Short-term complications of operative therapy include urinary retention, hematoma formation, and incontinence. Long-term complications, such as difficulty controlling flatus, daytime soiling of underwear, and nighttime incontinence, are noted with both open and closed internal sphincterotomy.

The exact incidence of long-term incontinence is not clear in the pediatric literature. The incidence of this complication is likely to remain unclear because medical management, including chemical sphincterotomy, is increasingly favored over surgery for chronic fissures.

Long-Term Monitoring

Dietary modifications, stool softeners, and sitz baths should be continued for several weeks after operative treatment. A follow-up visit is scheduled for 2-3 weeks after the procedure.