Anal canal is the terminal part of the gastrointestinal tract



Міністерство охорони здоров'я України

Міністерство освіти і науки України

Сумський державний університет

Медичний інститут СумДУ

До друку та в світ

дозволяю на підставі

« Єдиних правил »,

п. 2. 6. 14

Заст. першого проректора –

начальник організаційно –

методичного управління В. Б. Юскаєв

Методичні вказівки

на тему

«Anorectal diseases»

для студентів старших курсів, які навчаються англійською мовою

Усі цитати, цифровий

та фактичний матеріал,

бібліографічні дані

перевірені, запис одиниць

відповідає стандартам

Укладач: О.Л. Ситнік

Відповідальний за випуск: д. мед. н., проф. М.Г. Кононенко

Директор Медичного

інституту СумДУ В. Е. Маркевич

Суми

Видавництво СумДУ

2008

Навчальне видання

Методичні вказівки

на тему

«Anorectal diseases»

для студентів старших курсів, які навчаються англійською мовою

Укладач О.Л. Ситнік

Відповідальний за випуск М.Г. Кононенко

Підп. до друку 20.05.2008, поз.

Формат 60×84/16. Папір офс.

Гарнітура Times New Roman Сyr Друк офс.

Ум. друк. арк.1,62. Обл.-вид. арк.1.25.

Тираж 100 пр. Собівартість вид.

Зам. №

Видавництво СумДУ при Сумському державному університеті

40007, Суми, вул. Р.-Корсакова, 2

Свідоцтво про внесення суб'єкта видавничої справи до Державного реєстру ДК № 3062 17.12.2007р.

Надруковано у друкарні СумДУ

40007, Суми, вул. Р.-Корсакова, 2

Міністерство охорони здоров'я України

Міністерство освіти і науки України

Сумський державний університет

Медичний інститут СумДУ

Методичні вказівки

на тему

«Anorectal diseases»

для студентів старших курсів, які навчаються англійською мовою

Суми

Видавництво СумДУ

2008

Методичні вказівки на тему «Anorectal diseases» для студентів старших курсів, які навчаються англійською мовою / Укладач О.Л. Ситнік. - Суми: Вид-во СумДУ, 2008. – 28 с.

Кафедра хірургії з дитячою хірургією та курсом онкології

Anal canal is the terminal part of the gastrointestinal tract. Diseases of anal canal are wide-spread conditions. Many physicians do not understand the anorectal area and the common diseases associated with it.

The general purpose of lesson is: student has to diagnose a case, to define the tactics of treatment, to choose the optimum method of operation in patients with anal canal diseases.

Concrete purposes of lesson are:

1. Student has to reveal in patient’s history factors which are important in beginning and developing of anal canal diseases..

2. Student has to form the diagnostic algorithm.

3. Student has to make differential diagnoses of anal canal diseases.

4. Student has to form the tactics of treatment in patients with uncomplicated and complicated anal canal diseases.

5. Student has to choose the optimum method of operation in patient with anal canal disease.

6. Student has to prescribe postoperative treatment.

Hemorrhoids

Frequency

Ten million people in United States have hemorrhoids, leading to a prevalence greater than 4%. Up to a third of these people seek medical treatment, resulting in 1.5 million prescriptions per year. The peak age is 45-65 years.

Etiology

Inflammatory bowel disease and hemorrhoidal problems occur frequently. Unusual presentations and findings should alert the clinician to the potential of inflammatory bowel disease. Ulcerative colitis and Crohn disease may be associated with hemorrhoids. Pregnancy is also associated with many anorectal problems.

Pathophysiology

The term hemorrhoid is usually related to symptoms caused by hemorrhoids. Hemorrhoids are present in healthy individuals. When these vascular cushions produce symptoms, most laypersons and physicians refer to them as hemorrhoids. Hemorrhoids generally cause symptoms when they become enlarged, inflamed, thrombosed, or prolapsed.

Most authors agree that low-fiber diets cause small-caliber stools, which result in straining with defecation. This increased pressure causes engorgement of the hemorrhoids, possibly by interfering with venous return. Pregnancy and abnormally high tension of the internal sphincter muscle can also cause hemorrhoidal problems, presumably by means of the same mechanism. Decreased venous return is thought of as the mechanism of action. Prolonged sitting on a toilet (e.g., while reading) is believed to cause a relative venous return problem in the perianal area (a tourniquet effect), resulting in enlarged hemorrhoids. Aging causes weakening of the support structures, which facilitates prolapse. Weakening of support structures can occur as early as the third decade of life.

Straining and constipation have long been thought of as culprits in the formation of hemorrhoids. This may or may not be true. Patients who report hemorrhoids have a canal-resting tone that is higher than normal. Of interest, the resting tone is lower after hemorrhoidectomy than before. This change in the resting tone is the mechanism of action of Lord dilatation, which is most commonly performed in the United Kingdom.

Pregnancy clearly predisposes women to symptoms from hemorrhoids, although the etiology is unknown. Notably, most patients revert to their previously asymptomatic state after delivery. The relationship between pregnancy and hemorrhoids lends credence to hormonal changes or direct pressure as the culprit.

Portal hypertension has often been mentioned in conjunction with hemorrhoids. Hemorrhoidal symptoms do not occur more frequently in patients with portal hypertension than in those without. Massive bleeding from hemorrhoids in these patients is unusual. Bleeding is very often complicated by coagulopathy. If bleeding is found, direct suture ligation of the offending column is suggested. Anorectal varices are common in patients with portal hypertension. Varices occur in the mid rectum, at connections between the portal system and the middle and inferior rectal veins. Varices occur more frequently in patients who are noncirrhotic, and they rarely bleed.

Relevant Anatomy

Hemorrhoids are not varicosities; they are clusters of vascular tissue, smooth muscle, and connective tissue lined by the normal epithelium of the anal canal. Hemorrhoids are categorized into internal and external hemorrhoids (fig. 1). These categories are anatomically separated by the dentate (pectinate) line.

[pic]

Figure1. External and internal hemorrhoids

External hemorrhoids are hemorrhoids covered by squamous epithelium, whereas internal hemorrhoids are lined with columnar epithelium. Similarly, external hemorrhoids are innervated by cutaneous nerves that supply the perianal area. These nerves include the pudendal nerve and sacral plexus. Internal hemorrhoids are not supplied by somatic sensory nerves and therefore cannot cause pain. At the level of the dentate line, internal hemorrhoids are anchored to the underlying muscle by the mucosal suspensory ligament.

Hemorrhoids have 3 main cushions. These cushions are situated in the left lateral, right posterior, and right anterior areas of the anal canal. Minor tufts can be found between the cushions. Internal hemorrhoids have 3 main cushions. These cushions are situated in the left lateral, right posterior, and right anterior areas of the anal canal. Minor tufts can be found between the cushions.

Clinical

Most laypersons and many physicians attribute all perianal symptoms to hemorrhoids. The astute physician can often listen to patient reports and ascertain the source of the problem or condition before confirmatory examination. Nonhemorrhoidal causes of symptoms (e.g., fissure, abscess, fistula, pruritus ani, condylomata, viral and bacterial skin infections) should be excluded.

Hemorrhoidal symptoms are divided into internal and external sources. Internal hemorrhoids cannot cause cutaneous pain. They can bleed, prolapse and cause perianal itching and irritation. Internal hemorrhoids can cause perianal pain by prolapsing and causing spasm of the sphincter complex around the hemorrhoids. This spasm results in discomfort while the prolapsed hemorrhoids are exposed. The discomfort is relieved with reduction. Internal hemorrhoids can also cause acute pain when incarcerated and strangulated. Again, the pain is related to the sphincter complex spasm. Strangulation with necrosis may cause more deep discomfort. When these catastrophic events occur, the sphincter spasm often causes concomitant external thrombosis. External thrombosis causes acute cutaneous pain.

Internal hemorrhoids most commonly cause painless bleeding with bowel movements. The covering epithelium is damaged by the hard bowel movement and the underlying veins bleed. With spasm of the sphincter complex elevating pressure, the internal hemorrhoidal veins can spurt. Internal hemorrhoids can deposit mucus onto the perianal tissue with prolapse. This mucus with microscopic stool contents can cause a localized dermatitis, which is called pruritus ani.

Internal hemorrhoids are classified by symptom. Grade I hemorrhoids only bleed. Grade II hemorrhoids prolapse and reduce spontaneously. Grade III hemorrhoids require manual replacement, and grade IV hemorrhoids are permanently prolapsed.

External hemorrhoids cause symptoms in 2 ways. First, acute thrombosis of the underlying external hemorrhoidal vein can occur. Acute thrombosis is usually related to a specific event, eg, physical exertion, straining with constipation, a bout of diarrhea, or a change in diet. These are acute, painful events. Pain results from rapid distension of innervated skin by the clot and surrounding edema. The pain lasts 7-14 days and resolves with resolution of the thrombosis. With resolution of the thrombosis, the stretched anoderm persists as excess skin or skin tags. External thromboses can occasionally erode the overlying skin and cause bleeding.

Recurrence occurs approximately 40-50% of the time, at the same site. This occurs at the same site because the underlying damaged vein remains present.

External hemorrhoids can cause trouble with hygiene. External hemorrhoidal veins found under the perianal skin obviously cannot cause hygiene problems; however, excess skin in the perianal area can mechanically interfere with cleansing.

Diagnostic procedures.

Examination begins with inspection and examination of the entire perianal area. Warn the patient before any probing or poking. Patient apprehension is great prior to any anal examination. Go to great lengths to reassure the patient. Gentle spreading of the buttocks allows easy visualization of most of the anoderm; this includes the distal anal canal. Anal fissures and perianal dermatitis are easily visible without internal probing. Note the location and size of skin tags and the presence of thromboses. Normal corrugation of the anoderm and a normal anal wink with stimulation confirms intact sensation.

Digital examination of the anal canal can identify any indurated or ulcerated areas. Be sure to palpate the prostate in all men. Because internal hemorrhoids are soft vascular structures, they are usually not palpable.

Anoscopy is mandatory for viewing internal hemorrhoids. The anoscope should be a side-viewing scope. When angled well by the examiner, the side-viewing anoscope allows the soft hemorrhoidal tufts to fill the beveled end of the scope and to be appropriately evaluated. Prolapse can be observed when the patient performs a Valsalva maneuver.

Flexible sigmoidoscopy is performed to exclude proximal disease. Having a patient strain while sitting on a toilet may reproduce prolapse most accurately.

Examining patients while they sit on a toilet can be very helpful in indeterminate cases. Colonoscopy, virtual colonoscopy, and barium enema are reserved for cases of bleeding without an identified anal source. These symptoms are not attributable to hemorrhoids and are considered non–outlet-type bleeding.

Medical therapy

Treatment is divided by the cause of symptom into internal and external treatments. Internal hemorrhoids do not have cutaneous innervations and thus can be destroyed without anesthetic.

Because most physicians believe that straining and a low-fiber diet cause hemorrhoidal disease, conservative treatment includes increasing fiber and liquid intake and retraining in toilet habit.

Psyllium seed significantly decreases bleeding and pain. The average American diet consists of 8-15. grams of fiber per day. A high-fiber diet includes more than 25 grams of fiber per day. Psyllium seed and methylcellulose are the most commonly used supplements.

Many hemorrhoid symptoms resolve when only when they are treated with dietary alterations, including increased fiber and adding fiber supplements.

Antidiarrheal agents are sometimes required in patients with symptoms and loose stools. Toilet retraining involves reminding patients that the lavatory is not the library. Patients should sit on the toilet only long enough to evacuate the lower intestines. Persistent straining or prolonged sitting can lead to engorged hemorrhoids.

Stool softeners play a limited role in the treatment of routine hemorrhoidal symptoms. Oral fiber intake and fiber supplements almost always cure constipation and straining. Remember that hemorrhoidal symptoms are due to prolapse, thrombosis, and vascular bleeding; therefore, creams and salves have a small role in treating hemorrhoidal complaints. Suppositories, except for providing lubrication, have a small role in the treatment of hemorrhoidal symptoms. Topical hydrocortisone can sometimes ease internal hemorrhoidal bleeding. The author rarely recommends typical medications (e.g., suppository, cream, enema, foam) in the treatment of hemorrhoids.

Submucosal veins do not get smaller with anti-inflammatory medications. Bathing in tubs with warm water universally eases painful perianal conditions. Relaxation of the sphincter mechanism and spasm is probably the etiology. Ice can relieve the pain of acute thrombosis.

Surgical therapy

Operative resection is reserved for patients with grade III and grade IV hemorrhoids, patients who fail nonoperative therapy, and patients who also have significant symptoms from external hemorrhoids or skin tags.

Laser hemorrhoidectomy, as opposed to conventional scalpel and electrocautery techniques, is associated with many myths. Hemorrhoidectomy factories have touted painless or decreased pain and shortened healing times as advantages to performing hemorrhoidectomies by laser. No documented studies support these claims. In fact, one prospective study found no difference between scalpel and laser hemorrhoidectomy. The reader is referred to appropriate textbooks to see descriptions of techniques used.

External hemorrhoids generally elicit symptoms due to acute thrombosis, recurrent thromboses, or hygiene problems. Manage acute thromboses and recurrent thromboses in a similar fashion. Identify the offending vascular cluster. In the office or clinical setting, inject local anesthetic, then perform excision of the overlying skin and underlying veins.

Enucleation of the thrombosis alone can result in recurrence of the hemorrhoid at the same spot in the future. Excision of the underlying vein completely prevents this embarrassing event. Electrocoagulation or topical astringent (Monsel solution) provides hemostasis. Suturing the wound closed is not necessary and may cause more pain. Remember, acute thromboses spontaneously resolve in 10-14 days; therefore, a patient who presents late and has diminishing pain is best left alone. Recurrence occurs up to 50% of the time when thromboses are left alone.

Stapled hemorrhoid surgery, or procedure for prolapse and hemorrhoids (PPH), has recently become prominent. It was first described in 1997 and 1998. During PPH, a specially designed circular stapler with smaller staples is used. The technique involves placing a suture in the mucosa and submucosal layers circumferentially approximately 3-4 cm above the dentate line. The stapler is placed and slowly closed around the purse string. Care is taken to draw excess hemorrhoid tissue into the stapler. The stapler is fired, resecting the excess tissue and placing a circular staple line above the dentate line. This results in resection of excessive internal hemorrhoidal tissue, pexy of the internal hemorrhoidal tissue left behind and interruption of the blood supply from above. It can be done as an outpatient, using local anesthesia with intravenous (IV) sedation.

PPH is mainly used to treat internal hemorrhoids not amenable to conservative and nonoperative therapies. Narcotic use and recovery is significantly decreased compared with conventional operative hemorrhoid surgery.

PPH does not directly affect the external tissue. Reports have described shrinking of external hemorrhoidal tissue after PPH, probably from decreased blood flow. PPH combined with judicial excision of occasional skin tags is also reported, with good results.

Patients receiving PPH seem to have less severe pain for a shorter duration compared with conventional surgery. The use of PPH is suggested in patients with large internal hemorrhoids and minimal external component. This procedure can be done in an outpatient setting with local anesthesia, similar to the protocol used for conventional hemorrhoid surgery.

Operative resection is reserved for patients with hygiene trouble caused by large skin tags, a history of multiple external thromboses, or internal hemorrhoid trouble. Perform the operation in the outpatient setting. Proper anesthetic care (especially if local anesthesia with supplementary IV sedation), attention to perioperative fluid restriction, and careful postoperative instructions can ease the patient's recovery.

Patients with ulcerative colitis can tolerate aggressive surgery if needed. Treat underlying acute disease before any elective anorectal surgery. Avoid aggressive treatment in patients with Crohn disease, especially if the rectal mucosa is acutely inflamed. Drain abscesses as soon as possible, despite active disease elsewhere. If necessary, operative hemorrhoidectomy is safe in pregnant women.

Acute hemorrhoidal crisis is a rare event that usually requires emergency treatment. The mechanism of action is large internal hemorrhoid prolapse. The sphincter mechanism squeezes, incarcerating the internal hemorrhoids and strangulates them. The resulting spasm causes edema and, occasionally, thrombosis of the external hemorrhoids. The resulting pain and swelling is dramatic and very painful. Emergent operative resection is safe and, with conservation of the anoderm, provides good relief. Rapid pain relief with office excision of thromboses and ligation of internal hemorrhoids has been reported.

Follow-up care

It includes monitoring of patients at regular intervals until they are healed and have no symptoms.

Perianal abscess

Perianal abscess represents an infection of the soft tissues surrounding the anal canal, with formation of a discrete abscess cavity. Anorectal abscesses originate from infection arising in the cryptoglandular epithelium lining the anal canal. The internal anal sphincter is believed to serve normally as a barrier to infection passing from the gut lumen to the deep perirectal tissues. This barrier can be breached through the crypts of Morgagni, which can penetrate through the internal sphincter into the intersphincteric space. Once infection gains access to the intersphincteric space, it has easy access to the adjacent perirectal spaces. Extension of the infection can involve the intersphincteric space, ischiorectal space, or even the supralevator space. In some instances, the abscess remains contained within the intersphincteric space.

Frequency

The peak incidence of anorectal abscesses is in the third to fourth decades of life. Men are affected more frequently than women, with male-to-female predominance of 2:1 to 3:1. Approximately 30% of patients with anorectal abscesses report a previous history of similar abscesses that either resolved spontaneously or required surgical intervention. A higher incidence of abscess formation appears to correspond with the spring and summer seasons. While demographics point to a clear disparity in the occurrence of anal abscesses with respect to age and sex, no obvious pattern exists among various countries or regions of the world. Although suggested, a direct relationship between bowel habits, frequent diarrhea, and poor personal hygiene and the formation of anorectal abscesses remains unproved.

Etiology

Perirectal abscesses and fistulas represent anorectal disorders arising predominately from the obstruction of anal crypts. Infection of the now static glandular secretions results in suppuration and abscess formation within the anal gland. The abscess typically forms initially within the intersphincteric space and then spreads along adjacent potential spaces.

Pathophysiology

Perirectal abscesses represent anorectal disorders that arise predominately from the obstruction of anal crypts. Normal anatomy demonstrates anywhere from 4-10 anal glands drained by respective crypts at the level of the dentate line. Anal glands normally function to lubricate the anal canal. Obstruction of anal crypts results in stasis of glandular secretions and, when subsequently infected, suppuration and abscess formation within the anal gland results. The abscess typically forms in the intersphincteric space and can spread along various potential spaces. Common organisms implicated in abscess formation include Escherichia coli, Enterococcus species, and Bacteroides species; however, no specific bacterium has been identified as a unique cause of abscesses. Less common causes of anorectal abscess that must be considered in the differential diagnosis include tuberculosis, cancer, Crohn disease, trauma, leukemia, and lymphoma.

Classification of anorectal abscess

Abscesses are classified based on their anatomical location. The most commonly described locations are perianal, ischiorectal, intersphincteric and supralevator.

Perianal abscesses represent the most common type of anorectal abscesses, accounting for approximately 60% of reported cases. These superficial collections of purulent material are located beneath the skin of the anal canal and do not transverse the external sphincter.

The next most common types of abscesses in descending order of frequency are ischiorectal, intersphincteric, and supralevator. An ischiorectal abscess forms when suppuration transverses the external sphincter into the ischiorectal space. Intersphincteric abscesses result from suppuration contained between the internal and external anal sphincters. A supralevator abscess results either from suppuration extending cranially through the longitudinal muscle of the rectum from an origin in the intersphincteric space to reach above the levators or as a result of primary disease in the pelvis.

Clinical sings

The classic locations of anorectal abscesses listed in order of decreasing frequency are as follows: perianal 60%, ischiorectal 20%, intersphincteric 5%, supralevator 4%, and submucosal 1%. Clinical presentation correlates with the anatomical location of the abscess.

Patients with perianal abscesses typically complain of dull perianal discomfort and pruritus. Their perianal pain often is exacerbated by movement and increased perineal pressure from sitting or defecation. Physical examination demonstrates a small, erythematous, well-defined, fluctuant, subcutaneous mass near the anal orifice.

Patients with ischiorectal abscesses often present with systemic fevers, chills, and severe perirectal pain and fullness consistent with the more advanced nature of this process. External signs are minimal and may include erythema, induration, or fluctuance. On digital rectal examination (DRE), a fluctuant indurated mass may be encountered. Optimal physical assessment of an ischiorectal abscess may require anesthesia to alleviate patient discomfort that would otherwise limit the extent of the examination.

Patients with intersphincteric abscesses present with rectal pain and exhibit localized tenderness on DRE. Physical examination may fail to identify an intersphincteric abscess.

Lab studies

No specific laboratory studies are indicated in the evaluation of a patient with a perianal or anorectal abscess.

Imaging Studies:

Imaging studies rarely are necessary in evaluation of the patient with an anorectal abscess; however, clinical suspicion of an intersphincteric or supralevator abscess may require confirmation by CT scan, MRI, or anal ultrasonography.

Medical therapy

In most patients with anorectal abscess, adjuvant medical therapy with antibiotics generally is not necessary. The presence of a systemic inflammatory response, diabetes, or immunosuppression justifies concomitant use of antibiotics.

Surgical therapy

Treatment of anorectal abscesses involves early surgical drainage of the purulent collection. Primary antibiotic therapy alone is ineffective in resolving the underlying infection and simply postpones surgical intervention. Any delay in surgical drainage of anorectal abscesses prolongs infection, augments tissue damage, may impair sphincter continence function, and may promote stricture and/or fistula formation.

Drainage of perianal or superficial abscesses usually can be accomplished in the office or emergency department using local anesthetics. A small incision is made over the area of fluctuance in close proximity to the anal verge. Pus is collected and sent for culture. Hemostasis is achieved with manual pressure, and the wound is packed with iodophor gauze. The gauze is removed after 24 hours, and the patient is instructed to take sitz baths 3 times a day and after bowel movements. Postoperative analgesics and stool softeners are prescribed to relieve pain and prevent constipation. The patient typically will follow up with his/her physician in 2-3 weeks for wound evaluation and inspection for possible fistula in ano.

Treatment of ischiorectal, intersphincteric, and supralevator abscesses is performed best under general or regional anesthesia. In the case of ischiorectal abscess, a cruciate incision is made at the site of maximal swelling. Pus is drained and cultured. The ischiorectal fossa is probed with a finger or hemostat to disrupt loculations and facilitate drainage.

To drain an ischiosphincteric abscess, a transverse incision is made within the anal canal below the dentate line posteriorly. The intersphincteric space is identified, and the plane between the internal and external sphincters is exposed. The abscess is opened to allow drainage, and a small mushroom catheter is sutured in situ to assist drainage and prevent premature wound closure.

Location and etiology will determine the drainage technique of supralevator abscesses. Failure to manage supralevator abscesses with consideration of the primary etiology may result in iatrogenic fistula formation. Evaluation with MRI or CT scan can exclude intra-abdominal or pelvic pathology as possible sources. If the supralevator abscess evolved from the extension of an ischiorectal abscess, external drainage through the ischiorectal fossa is indicated. If the abscess resulted from an upward extension of an intersphincteric abscess, appropriate drainage is created through the rectal mucosa. In cases of posterior supralevator abscess collections, a transverse incision is made in the posterior anal canal below the dentate line. The dissection extends from the intersphincteric plane through the puborectalis sling into the posterior anal space. A mushroom catheter then is sutured in place to ensure adequate drainage.

Anterior supralevator abscesses are superficial and more common in women. Surgical drainage may be approached using an anteriorly directed transanal incision or by a transvaginal approach entering the posterior cul-de-sac.

Follow-up care

The patient typically will follow up with his/her physician in 2-3 weeks for wound evaluation and inspection for possible fistula in ano.

Fistula-in-ano

A fistula-in-ano is a hollow tract lined with granulation tissue connecting a primary opening inside the anal canal to a secondary opening in the perianal skin. Secondary tracts may be multiple and from the same primary opening.

Frequency

The prevalence rate is 8.6 cases per 100,000 populations. The prevalence in men is 12.3 cases per 100,000 populations. In women, it is 5.6 cases per 100,000 populations. The male-to-female ratio is 1.8:1. The mean age of patients is 38.3 years.

Etiology

Fistula-in-ano is nearly always caused by a previous anorectal abscess. Anal canal glands situated at the dentate line afford a path for infecting organisms to reach the intramuscular spaces.

Other fistulae develop secondary to trauma, Crohn disease, anal fissures, carcinoma, radiation therapy, actinomycoses, tuberculosis, and chlamydial infections.

Pathophysiology

The cryptoglandular hypothesis states that an infection begins in the anal gland and progresses into the muscular wall of the anal sphincters to cause an anorectal abscess. Following surgical or spontaneous drainage in the perianal skin, occasionally a granulation tissue–lined tract is left behind, causing recurrent symptoms. Multiple series have shown that the formation of a fistula tract following anorectal abscess occurs in 7-40% of cases.

Clinical history

Patients often provide a reliable history of previous pain, swelling, and spontaneous or planned surgical drainage of an anorectal abscess.

Signs and symptoms (in order of prevalence):

perianal discharge;

pain;

swelling;

bleeding;

diarrhea;

skin excoriation;

external opening.

Important points in the history that may suggest a complex fistula include the following:

inflammatory bowel disease;

diverticulitis;

previous radiation therapy for prostate or rectal cancer;

tuberculosis;

steroid therapy;

HIV infection.

Physical examination

Physical examination findings remain the mainstay of diagnosis. The examiner should observe the entire perineum, looking for an external opening that appears as an open sinus or elevation of granulation tissue.

Digital rectal examination may reveal a fibrous tract or cord beneath the skin. It also helps delineate any further acute inflammation that is not yet drained. Lateral or posterior induration suggests deep postanal or ischiorectal extension.

The examiner should determine the relationship between the anorectal ring and the position of the tract before the patient is relaxed by anesthesia.

The sphincter tone and voluntary squeeze pressures should be assessed before any surgical intervention to delineate whether preoperative manometry is indicated. Anoscopy is usually required to identify the internal opening.

Classification systems

I.The Parks classification system defines 4 types of fistula-in-ano that result from cryptoglandular infections:

intersphincteric;

transsphincteric;

suprasphincteric;

extrasphincteric.

II.Current procedural terminology codes classification:

subcutaneous;

submuscular (intersphincteric, low transsphincteric);

complex, recurrent (high transsphincteric, suprasphincteric and extrasphincteric, multiple tracts, recurrent);

Lab studies

No specific laboratory studies are required.

Imaging Studies

Radiologic studies. These are not performed for routine fistula evaluation. They can be helpful when the primary opening is difficult to identify or in the case of recurrent or multiple fistulae to identify secondary tracts or missed primary openings.

Fistulography. This involves injection of contrast via the internal opening, which is followed by anteroposterior, lateral, and oblique x-ray images to outline the course of the fistula tract.

Endoanal/endorectal ultrasound. These studies involve passage of a 7- or 10-MHz transducer into anal canal to help define muscular anatomy differentiating intersphincteric from transsphincteric lesions.

MRI. Findings show 80-90% concordance with operative findings when observing a primary tract course and secondary extensions. MRI is becoming the study of choice when evaluating complex fistulae. It has been shown to improve recurrence rates by providing information on otherwise unknown extensions.

CT scan. A CT scan is more helpful in the setting of perirectal inflammatory disease than in the setting of small fistulae because it is better for delineating fluid pockets that require drainage than for small fistulae. CT scan requires administration of oral and rectal contrast. Muscular anatomy is not delineated well. A barium enema/small bowel series: This is useful for patients with multiple fistulae or recurrent disease to help rule out inflammatory bowel disease.

Anal manometry. Pressure evaluation of the sphincter mechanism is helpful in certain patients.

Proctosigmoidoscopy/colonoscopy. Rigid sigmoidoscopy can be performed at the initial evaluation to help rule out any associated disease process in the rectum.

Medical therapy

No definitive medical therapy is available.

Surgical therapy

Fistulotomy/fistulectomy. The laying-open technique (fistulotomy) is useful for 85-95% of primary fistulae (i.e., submucosal, intersphincteric, low transsphincteric).

A probe is passed into the tract through the external and internal openings. The overlying skin, subcutaneous tissue, and internal sphincter muscle are divided with a knife or electrocautery, thereby opening the entire fibrous tract.

Complete fistulectomy creates larger wounds that take longer to heal and offers no recurrence advantage over fistulotomy.

Complications

Early postoperative:

urinary retention;

bleeding;

fecal impaction4

thrombosed hemorrhoids.

Delayed postoperative:

recurrence;

incontinence (stool);

anal stenosis.

Anal fissure

An anal fissure is a painful linear tear or crack in the distal anal canal, which, in the short term, usually involves only the epithelium and, in the long term, involves the full thickness of the anal mucosa.

Frequency

Anal fissures occur with equal frequency in both sexes. Additionally, anal fissures tend to occur in younger and middle-aged persons.

Etiology and pathophysiology

The exact etiology of anal fissures is unknown, but the initiating factor is thought to be trauma from the passage of a particularly hard or painful bowel movement. Low-fiber diets, such as those lacking in raw fruits and vegetables, are associated with the development of anal fissures. No occupations are associated with a higher risk for the development of anal fissures. Prior anal surgery is a predisposing factor because scarring from the surgery may cause either stenosis or tethering of the anal canal, which makes it more susceptible to trauma from hard stool.

Initial minor tears in the anal mucosa due to a hard bowel movement probably occur often, and, in most people, these heal rapidly without long-term sequelae. In patients with underlying abnormalities of the internal sphincter, these injuries progress to acute and chronic anal fissures. Studies of the internal anal sphincter and of anal canal physiology have been performed with varied results, but at least one abnormality is likely present in the internal anal sphincter of many anal fissure patients.

The most commonly observed abnormalities are hypertonicity and hypertrophy of the internal anal sphincter, leading to elevated anal canal and sphincter resting pressures. The internal sphincter maintains the resting pressure of the anal canal, and anal-rectal manometry can be used to measure this pressure. Most patients with anal fissures have an elevated resting pressure, and this resting pressure returns to normal levels after surgical sphincterotomy.

The posterior anal commissure is the most poorly perfused part of the anal canal. In patients with hypertrophied internal anal sphincters, this delicate blood supply is further compromised, thus rendering the posterior midline of the anal canal relatively ischemic.

This is thought to account for why many fissures do not heal spontaneously and may last for several months. Pain accompanies each bowel movement as this raw area is stretched and the injured mucosa is abraded by the stool.

The internal sphincter also begins to spasm when a bowel movement is passed, which has 2 effects. First, the spasm itself is painful; second, the spasm further reduces the blood flow to the posterior midline and the anal fissure, contributing to the poor healing rate.

Clinical sings

Typically, the symptoms of an anal fissure are relatively specific, and the diagnosis can often be made based on history findings alone. The patient reports severe pain during a bowel movement, with the pain lasting several minutes to hours afterward. The pain recurs with every bowel movement, and the patient commonly becomes afraid or unwilling to have a bowel movement, leading to a cycle of worsening constipation, harder stools, and more anal pain. Approximately 70% of patients note bright red blood on the toilet paper or stool. Occasionally, a few drops may fall in the toilet bowl, but significant bleeding does not usually occur with an anal fissure.

Initially, the fissure is just a tear in the anal mucosa and is defined as an acute anal fissure. If the fissure persists over time, it progresses to a chronic fissure that can be distinguished by its classic features. The fibers of the internal anal sphincter are visible in the base of the chronic fissure, and often, an enlarged anal skin tag is present distal to the fissure and hypertrophied anal papillae are present in the anal canal proximal to the fissure.

Most anal fissures occur in the posterior midline, with the remainder occurring in the anterior midline (99% of men, 90% of women). Two percent of patients have both anterior and posterior fissures. Fissures occurring off the midline should raise the possibility of other etiologies (e.g., Crohn disease), an infectious etiology (e.g., sexually transmitted disease,

Relevant anatomy

Anal canal. The anal canal has 2 definitions. The first is the functional or surgical anal canal, and the second is the anatomic anal canal. The terms are often used interchangeably, even though they do not mean the same thing. The surgical anal canal is approximately 4 cm long and extends from the anal verge or intersphincteric groove distally to the anorectal ring proximally. The anatomic anal canal is only approximately 2 cm long and extends from the anal verge distally to the dentate line proximally.

Anal verge. The anal verge is an anocutaneous line approximately 2 cm distal to the dentate line. The anal verge marks the beginning of the anal canal.

Dentate line. The dentate line is the junction of the ectoderm and endoderm in the anal canal.

Internal anal sphincter. The internal anal sphincter is a smooth muscle that is the most distal extension of the inner circular smooth muscle of the colon and the rectum. It is 2.5-4 cm long and is normally 2-3 mm thick. The internal sphincter is not under voluntary control and is continuously contracted to prevent unplanned loss of stool.

External anal sphincter. The external anal sphincter is striated muscle that forms a circular tube around the anal canal. Proximally, it merges with the puborectalis muscle and the levator ani to form a single complex. Control of the external anal sphincter is voluntary.

Lab studies

If an ordinary anal fissure is suggested and if it is located in the posterior or anterior midline, then no laboratory tests are necessary.

If the fissure is off the midline, is irregular, or if an underlying illness (eg, Crohn disease, squamous cell cancer, AIDS) may be present, then order appropriate tests, which may include erythrocyte sedimentation rate, stool and viral cultures, HIV testing, or biopsy of the lesion/fissure (as warranted).

Imaging studies

No imaging studies are required for diagnosis or treatment.

Diagnostic procedures

Along with a history, the diagnosis can usually be made based on findings from a gentle perianal examination with inspection of the anal mucosa. In this case, no diagnostic procedures are required. A digital rectal examination is painful and often can be deferred.

Occasionally, the fissure is not easily visualized, and anoscopy is required to see it. However, this is not well tolerated by a patient with an acute anal fissure, and anoscopy can often be deferred and the patient treated based on symptoms only. Occasionally, a topical application of 1-2% lidocaine facilitates the examination.

Patients who do not heal, those who have relief from symptoms with appropriate therapy, or those who have a recurrent anal fissure after surgical therapy should be evaluated further with anoscopy and rigid proctosigmoidoscopy to exclude other pathologies. Patients with chronic fissures tend to have less pain and can better tolerate either anoscopy or rigid proctosigmoidoscopy and should have this included in their evaluation.

Medical therapy.

Initial therapy for an anal fissure is medical in nature, and more than 80% of acute anal fissures resolve without further therapy.

The goals of treatment are to relieve the constipation and to break the cycle of hard bowel movement, associated pain, and worsening constipation.

Softer bowel movements are easier and less painful for the patient to pass.

First-line medical therapy consists of therapy with stool-bulking agents, such as fiber supplementation and stool softeners. Laxatives are used as needed to maintain regular bowel movements. Mineral oil may be added to facilitate passage of stool without as much stretching or abrasion of the anal mucosa, but it is not recommended for indefinite use. Sitz baths after bowel movements and as needed provide significant symptomatic relief because they relieve some of the painful internal sphincter muscle spasm.

Recurrence rates range from 30-70% if the high-fiber diet is abandoned after the fissure is healed. This rate can be reduced to 15-20% if patients remain on a high-fiber diet.

Second-line medical therapy is the topical application of 0.2% nitroglycerin (NTG) ointment directly to the internal sphincter. Some physicians use NTG ointment as initial therapy in conjunction with fiber and stool softeners, and others prefer to add it to the medical regimen if fiber and stool softeners alone fail to heal the fissure. NTG ointment is thought to relax the internal sphincter and to help relieve some of the pain associated with sphincter spasm; it also is thought to increase blood flow to the anal mucosa.

Unfortunately, many people cannot tolerate the adverse effects of NTG, often limiting its use. The main adverse effects are headache and dizziness; therefore, instruct patients to use NTG ointment for the first time in the presence of others or directly before bedtime.

The efficacy of NTG ointment has been debated in many studies, and its use is still controversial. NTG ointment is specially mixed at this lower concentration and is available only in pharmacies that specially make it.

Analogous to the use of NTG ointment, nifedipine ointment is also available for use in clinical trials. It is thought to have similar efficacy to NTG ointment but with fewer adverse effects.

A newer therapy for acute and chronic anal fissures is botulinum toxin (BOTOX®). The toxin is injected directly into the internal anal sphincter and, in effect, performs a chemical sphincterotomy. The effect lasts approximately 3 months, until the nerve endings regenerate. This 3-month period may allow acute fissures (and sometimes chronic fissures) to heal and symptoms to resolve. Initial relief of symptoms with BOTOX® injection but recurrence after 3 months suggests that the patient would benefit from surgical sphincterotomy.

Surgical therapy

Surgical therapy is usually reserved for acute anal fissures that remain symptomatic after 3-4 weeks of medical therapy and for chronic anal fissures.

Sphincter dilatation This procedure is a controlled anal stretch or dilatation under general anesthetic. This is performed because one of the causative factors for anal fissure is thought to be a tight internal anal sphincter; stretching it helps correct the underlying abnormality, thus allowing the fissure to heal. The number of fingers used and the amount of time the stretch is applied varies among surgeons. While the sphincter stretch does provide symptomatic relief from the anal fissure, it is rarely performed today because of the high complication rate. Impaired continence is observed in 12-27% of patients because of the uncontrolled stretching and subsequent tearing of both the internal and external sphincter.

Lateral internal sphincterotomy. This is the current surgical procedure of choice. The procedure can be performed with the patient under general or spinal anesthesia. (Local anesthesia may even be used in the cooperative patient, although this is not always recommended). The purpose of an internal sphincterotomy is to cut the hypertrophied internal sphincter, thereby releasing tension and allowing the fissure to heal.

When first described, the sphincterotomy was performed in the posterior midline at the site of the fissure with or without a fissurectomy.

However, the incision for the sphincterotomy usually did not heal for exactly the same reason that the fissure did not heal. Now, sphincterotomies are normally performed in the lateral quadrants (right or left, depending on the comfort or handedness of the surgeon). In a properly performed lateral internal sphincterotomy, only the internal sphincter is cut; the external sphincter is not cut and must not be injured.

The sphincterotomy can be performed in either an open or a closed manner.

In a closed sphincterotomy, a blade is inserted sideways into the intersphincteric groove laterally. It is then rotated medially and drawn out to cut the internal sphincter. Care is taken to not cut the anal mucosa because this could result in a fistula. After the knife is removed, the anal mucosa overlying the sphincterotomy is palpated, and a gap in the internal sphincter can be felt through it. The sphincterotomy is extended into the anal canal for a distance equal to the length of the anal fissure.

In an open sphincterotomy, a 0.5- to 1-cm incision is made in the intersphincteric plane. The internal sphincter is then looped on a right angle and brought up into the incision. The internal sphincter is then cut under direct visualization. The 2 ends are allowed to fall back after being cut. A gap can then be palpated in the internal sphincter through the anal mucosa, as in the closed technique. The incision can be closed or left open to heal.

In the treatment of chronic anal fissures, the surgeon may choose to excise the fissure in conjunction with the lateral sphincterotomy. Take care to not include a piece of the internal sphincter with the excision.

More simply, instead of excising the fissure along with the sphincterotomy and worrying whether it will heal, the surgeon can excise the hypertrophied papillae and the skin tag and leave the fissure to heal on its own. Sometimes, long-standing chronic fissures do not heal, even with an adequate sphincterotomy, and an advancement flap must be performed to cover the defect in the mucosa. This can be performed either at the time of the sphincterotomy if the surgeon does not think the fissure will heal or as a second procedure if the fissure does not heal.

Follow-up care

Prescribe stool softeners and fiber supplementation after

the surgery, and recommend fiber supplementation indefinitely to prevent future problems with constipation. Follow-up care usually consists of a single postoperative visit to ensure that the wound is healing appropriately and that the fissure has resolved.

Complications from surgery for anal fissure include infection, bleeding, fistula development, and—the most feared—incontinence.

Infection. Infection after sphincterotomy is rare and occurs as a small abscess in only 1-2% of patients, despite the inherent uncleanliness of the area.

Treatment is drainage of the abscess. Antibiotics are necessary only if significant associated cellulitis occurs or if the patient is immunosuppressed.

Bleeding. Some ecchymosis may occur around the sphincterotomy site, but bleeding that requires therapy is extremely rare.

Fistula formation. Fewer than 1% of patients develop an anal fistula at the site of the sphincterotomy. This usually results from a breach of the mucosa at the time of the sphincterotomy. The fistula is often low and superficial and should be treated with fistulotomy.

Incontinence. The incidence and definition of incontinence vary dramatically from study to study and among the different procedures. Of patients undergoing the sphincter stretch, 12-27% report problems with continence after the procedure. This is most likely because this is an uncontrolled stretch of the anal sphincter and that both the internal and external sphincters are stretched.

Incontinence rates are much lower with a properly performed internal sphincterotomy than with sphincter stretch, and these rates depend on the definition of incontinence. In most patients, the minor soiling or incontinence to flatulence that may occur in the immediate postoperative period usually resolves without any long-term sequelae.

Recurrence or nonhealing of the fissure. The recurrence rate or nonhealing rate for anal fissures after surgical treatment is 1-6%. Several studies have found that up to 50% of subjects who did not heal had underlying and undiagnosed Crohn disease as the etiology for their fissure.

Bibliography

1. Cheetham MJ, Cohen CR, Kamm MA: A randomized, controlled trial of diathermy hemorrhoidectomy vs. stapled hemorrhoidectomy in an intended day-care setting with longer-term follow-up. Dis Colon Rectum 2003 Apr; 46(4): 491-7.

2. Chandwani D, Shih R, Cochrane D: Bedside emergency ultrasonography in the evaluation of a perirectal abscess. Am J Emerg Med 2004 Jul; 22(4): 315.

3. Buchanan GN, Halligan S, Williams AB. Magnetic resonance imaging for primary fistula in ano. Br J Surg. Jul 2003;90(7):877-81.

4. Richard CS, Gregoire R, Plewes EA, et al: Internal sphincterotomy is superior to topical nitroglycerin in the treatment of chronic anal fissure: results of a randomized, controlled trial by the Canadian Colorectal Surgical Trials Group. Dis Colon Rectum 2000 Aug; 43(8): 1048-57; discussion 1057-8[Medline].

5. Robert E, Condon, M.D.- "Textbook of surgery"; W.B. Saunders com pany, Philadelphia, 1981. r

6. S.I. Shevchenko, A.A. Tonkoglas, I.N. Lodiena, "Surgery" Kharkov 2004.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download