severe constipation. Patients typically present with a painful, tender mass in the perianal area.

Frequently, the thrombosis will lead to necrosis of the overlying skin and patients will complain of

bleeding that is independent of bowel movements.

The management of thrombosed external hemorrhoids depends on when in the course of the disease

the patient presents. The pain associated with this condition typically peaks within 48 hours and

normally begins to subside after 4 days. If left untreated, the clot in the thrombosed vessels will

dissolve within several weeks. Following resolution, large thrombosed hemorrhoids may remain as skin

tags.

Because this condition is self-limiting, management is typically conservative and includes pain control

with a mild analgesic, warm sitz baths, and a bulk-producing agent (usually psyllium fiber). If the

patient presents within the first 48 hours, the procedure of choice is excision of the entire thrombosed

hemorrhoid (Fig. 70-14). This procedure may be performed in the office or emergency room with the

use of a local anesthetic. Using scissors, the thrombosed hemorrhoid is excised with the underlying vein;

it is important to excise the entire thrombus in order to prevent recurrence. The skin edges are then

reapproximated with the use of an absorbable suture or may be left open.

Incarcerated Hemorrhoids. Rarely, patients will present with prolapsed fourth-degree hemorrhoids

which have become incarcerated. While internal hemorrhoids do not typically cause pain, patients with

incarcerated hemorrhoids often have severe pain and may develop urinary retention. Edematous

prolapsed hemorrhoids are seen, often in combination with large external components as well.

Traditionally this condition has been treated with an urgent or emergent hemorrhoidectomy, however

there is concern that leaving inadequate anoderm between the excision sites may lead to postoperative

stenosis. Instead, patients may be treated with oral or intravenous pain medications and stool softeners,

allowing the edema to resolve and the prolapse to reduce. These patients should then be offered an

elective hemorrhoidectomy to prevent recurrence.

Anal Fissure

5 Anal fissure is an ulcer-like tear in the mucosal lining of the anal canal distal to the dentate line.

Although more commonly found in younger patients, fissures can occur at any age and equally afflict

male and females. Fissures can be classified as acute or chronic, and as primary or secondary. Primary

anal fissures are almost always located in the posterior or anterior midline, and are not associated with

any underlying disease. Secondary fissures may occur in a lateral position, and should alert the clinician

to the possibility of Crohn’s disease, HIV infection, tuberculosis, syphilis, or a hematologic malignancy.

Anal fissures that have been present for longer than 6 weeks duration are arbitrarily classified as

chronic.

The exact etiology is not known, however several mechanisms are thought to lead to the development

of anal fissure. Trauma to the anal canal appears to be the initiating factor, most commonly as the result

of passage of hard stool, as a low fiber diet seems to be associated with the development of anal

fissure.8 Fissure may also occur following prolonged bouts of diarrhea, or following childbirth, most

likely the result of forces from the fetus on the anal canal.

Hypertonicity of the IAS with resultant ischemia has also been implicated in development of chronic

anal fissure. Ninety percent of fissures are found in the posterior midline of the anal canal, where

Doppler flow studies and cadaver vascular injections have demonstrated relatively low perfusion.

Studies have shown that when compared with normal subjects, patients with chronic anal fissure have

higher resting pressure of the IAS. If the pressure within the anal sphincter approaches or exceeds the

intra-arterial pressure of the inferior rectal artery, this may lead to relative ischemia and the

development of an ischemic ulcer. This theory is strengthened by the fact that reduction of anal pressure

following sphincterotomy improves blood flow to the anal canal, thereby promoting healing of the

fissure.9

Clinical Manifestations

Anal fissure typically presents with pain during defecation and rectal bleeding. Patients often describe

the pain as knifelike or as a tearing sensation, which may persist for several hours or longer after bowel

movements. Rectal bleeding is typically bright red, and is separate from the stool and often seen only

after wiping. Constipation is a common complaint of patients with anal fissure, and is frequently both a

precipitating event and a result of patients’ fear of a painful bowel movement.

The diagnosis of anal fissure can be made on physical examination by gently spreading the buttocks

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apart to visualize the anal verge. Fissures will appear as a longitudinal or oval-shaped tear and may be

associated with a sentinel pile, a protruding skin tag at the distal end of the fissure. Fibers of the IAS

may be visible in chronic anal fissures. Once a diagnosis of fissure has been made, digital examination

or anoscopy adds little other than increased pain for the patient, and should therefore be avoided.

Management

Medical Management. Symptomatic relief of anal pain from fissures may be obtained by warm sitz

baths two to three times per day. Topical anesthetics or anti-inflammatory ointments may also be of

benefit. The majority of patients with acute anal fissure will respond to conservative measures including

sitz baths and the addition of a bulking agent such as psyllium fiber. Acute anal fissures often heal

within 6 weeks, although the recurrence rate approaches 20%.10

As anal fissure is associated with hypertonicity of the anal sphincter, medical therapy is directed as

decreasing resting anal pressures. Nitric oxide is a potent neurotransmitter that induces relaxation of the

IAS. Application of 0.2% nitroglycerin ointment twice daily has been shown to induce healing in as

many as 85% of patients,11 however, patient compliance is often low due to nitrate-induced headache.

Calcium-channel blockers have also been shown to reduce anal pressures. Topical diltiazem or nifedipine

has been shown to have healing rates equivalent or superior to nitroglycerin12 without the associated

side effects. Unfortunately, recurrence rates with all of these therapies approach 50% in many series.

Botulinum toxin is an endopeptidase that blocks acetylcholine release at the neuromuscular junction,

resulting in temporary paralysis of skeletal muscle. Although its exact mechanism of action in smooth

muscle is not understood, injection of the toxin also results in relaxation of the IAS. The technique, dose,

and success rates have widely varied in the literature, however some authors have reported success in

60% to 80% of patients. The most common side effect is temporary anal incontinence, typically only to

flatus. The use of botulinum toxin may be an option in patients who have failed topical treatment, but

who may be at a high risk of complications from surgery.

Figure 70-15. Lateral internal sphincterotomy (open method). A: The fissure in the midline is left alone. B: With a speculum used

to expose the left lateral quadrant, an incision is made through the subcutaneous tissue to expose both the subcutaneous external

sphincter and the internal sphincter. C: The internal sphincter is incised to its full thickness; care is taken not to cut the external

sphincter. D: The wound is closed.

Surgical Management. In patients with chronic or recurrent fissures that fail to heal with medical

management, surgical intervention is warranted. The most commonly performed procedure is the lateral

internal sphincterotomy, which is an outpatient procedure that may be performed under local, spinal, or

general anesthesia. When performed in an open fashion, an incision is made overlying the anal sphincter

complex in the lateral position away from the fissure (Fig. 70-15). The internal sphincter is identified,

and a portion of the muscle is cut typically extending cephalad to the level of the apex of the fissure.

The wound is then closed with an absorbable suture. The procedure can also be performed in a closed

fashion, where the scalpel is inserted into the intersphincteric groove, turned horizontally, and used to

cut the internal sphincter as the anal canal is stretched open with a speculum. Healing rates following

sphincterotomy range from 90% to 100%, however, impairment of continence following the procedure

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