Anorectal Disease

Anatomy Wall consists of mucosa, submucosa, and two complete muscle layers, inner circular, outer longitudinal. 12-15cm in length, reflection is 6-8cm above anus.

Anatomy Upper 1/3 ant/lat covered by peritoneum, middle 1/3 only anteriorly covered, lower 1/3 completely retroperitoneal.

Anatomy The rectum starts where tenia coli coalesce to form a complete layer of longitudinal muscle at level of sacral promontory. Three distinct curves, proximal and distal curve to the right, middle curves to the left. These folds are called Valves of Huston. This area is great for biopsy purposes as they do not contain all layers so risk of perforation is less.

Anatomy Waldeyer’s fascia is a dense connection between sacrum and rectum at 4th sacral body goes anteriorly to rectum, covering sacrum and overlying vessels and nerves. Dennonviller’s fascia is a retrovesical septum in men, rectovaginal in women. Pelvic floor is musculotendinous sheet formed by the levator ani muscle and is innervated by S4.

Anatomy The pubococcygeus, iliococcygeus, and puborectalis make the levator ani. These are paired muscles that are intertwined and act as a unit. The anal canal starts at pelvic diaphragm and ends at anal verge. Approximately 4cm long. The anatomic anal canal extends from anal verge to dentate line. Surgical anal canal is anal verge to anorectal ring, the circular upper border of puborectalis that is palpable by rectal exam. It is 1-1.5 cm from dentate line.

Anatomy The anal verge is the junction between anoderm and perianal skin. The dentate line is a true mucocutaneous junction located 1-1.5 cm from anal verge. A 6-12mm transitional zone exists above the line where squamous becomes cuboidal, then columnar. Anal sphincter mechanism made by internal and external sphincters.

Anatomy The internal sphincter is a specialized continuation of the circular smooth muscle layer of the rectum. It is involuntary, and contracted at rest. The intersphincteric plane is a fibrous continuation of the longitudinal smooth muscle layer of the rectum

Anatomy The external sphincter is a voluntary, striated muscle divided into three u-shaped loops (subcutaneous, superficial, and deep). Acts as a single functional unit. It is a continuation of the levator ani muscle, specifically of the puborectalis muscle.

Anatomy The puborectalis starts at the pubis and joins posterior to the rectum. It is normally contracted, making a 80 degree angulation of the anorectal junction.

Puborectalis

Anatomy The Columns of Morgnani consist of 8-14 longitudinal mucosal folds just above dentate line and forming the anal crypts at their distal end. Small glands empty into these crypts. The ducts of some of these glands penetrate the internal sphincter, the body of the gland resides in the intersphincteric plane. Arterial supply is superior, middle and inferior rectal arteries (IMA, Int. Iliac, int. pudendal a).

Anatomy Venous Drainage empties into portal and caval systems. Upper and middle rectum into SRVIMV Portal vein. The lower rectum and upper anal canal MRVIIVIVC. The Lower anal canal drains into the IRV IVC.

Anatomy Three submucosal internal hemorrhoidal plexuses above dentate line; left lateral, right posterolateral, right anterolateral. These drain into the superior rectal vein. Below the dentate line, the external hemorrhoid veins drain into the pudendal veins.

Normal Function Storage. Resting pressure is 10mmHg. Holds 650-1200 of liquid. More than 1500 is megarectum. Normal 250-750cc formed feces. External sphincter is 20% of resting pressure and 100% of generated squeeze pressure. Internal sphincter provides 80% of resting pressure.

Hemorrhoids These cushions are thought to act as a plug to the anal canal, and contribute 15-20% to the resting pressure of the anal canal. There are three of these cushions 11,3,7 o'clock.

Hemorrhoids Abnormal swelling of the cushions result in prolapse of the upper anal/lower rectal tissue thru the anal canal. This causes the symptoms of hemorrhoids: bleeding, discomfort, pruritis, prolapse, swelling, pain, discharge. Bleeding is the most common symptom, pain is not common, unless a associated fissure is present (20%), or it’s a thrombosed external. Classification of internal hemorrhoids.

Classification of Internal Hemorrhoids I- Bleed, but do not prolapse. II- Spontaneous prolapsing and reducing with or without bleeding. III- Prolapsing,that require manual reduction. IV- Prolapsed, cannot reduce.

Prolapsed Internal Hemorrhoids

Thrombosed External Hemorrhoid

Medical Treatment 90% can be treated with conservative medical and conservative non-surgical measures. Fiber, avoid constipation, diarrhea if causative. Lidocaine jelly, HCTcream, NTG cream. Sclerotherapy, band ligation, infrared photocoagulation.

Surgical Hemorrhoidectomy Intended to restore the anal canal to normal or nearly normal functional and anatomical status. Surgery involves eliminating the vascular cushions alone or in combination with relocation of the squamous epithelium. Open (Milligan-Morgan) and Closed (Ferguson-Heaton).

Surgical Hemorrhoidectomy Excision of all the internal and external components of the cushions and closure of the defect primarily. Prone Jack-Knife position, butt taped apart.

Open Hemorrhoidectomy

Closed Hemorrhoidectomy Hill-Ferguson retractor in place, grab cushion, place suture at apex 4cm above dentate line, elliptical excision down to sphincter. Close from ligated pedicle out to skin. Complications: urinary retention, bleeding, stenosis, incontinence, infection.

Closed Hemorrhoidectomy

Hemorrhoidectomy Pain is still the major drawback of the operation. Circular stapled hemorrhoidectomy. Less pain. Learning curve. Rectal wall injury, rectovaginal fistula, death. Widely used throughout Europe.

Anal Fissures Traditionally attributed to constipation and passage of hard stool. Only a minority can recall an episode of this, so multifactorial problem.

Anal Fissures Associated with IBD, trauma, diarrhea, infectious. Hypertonicity of anal sphincter is thought to be main problem here.

Anal Fissures Studies using anal manometry done, showed these people had higher resting pressures. After lateral sphincterotomy, pressures significantly reduced with fissure healing. Also studied using NTG paste, and found same thing, except, the NTG is not long lasting, and pressure went back up, so did recurrent fissures.

Anal Fissures Ischemia of the anal mucosa is also thought to be involved, may account for majority being in the posterior midline. Studies show the higher the tone, the less blood flow to the posterior midline. Lateral sphincterotomy reverses this.

Anal Fissure

Anal Fissures SSX are painful BMs with bleeding. Sharp, stabbing ripping. Signs of chronicity (>4weeks) is a sentinel skin pile at distal margin of lesion. Circular fibers of internal sphincter my be seen at base. Non-operative treatment excellent for acute fissures. Fiber, stool softeners, sitz baths, local anesthetics, Botox, Nitrates.

Anal Fissure

Surgical Treatment of Fissures Anal Sphincter Stretch- gradual dilation of anal canal to accommodate 4 fingers. Can use Parks retractor, Balloon inflation. Lateral sphincterotomy- open vs. closed. Healing rate 98%. Incontinence 12-15% (open). 25% incontinent to flatus regardless of procedure. Higher rates of satisfaction for closed, lower rates of incontinence for closed.

Lateral Sphincterotomy (Closed)

Anorectal Abscess Causes can be infectious, IBD, malignancy, TB, FB, trauma. Majority are in otherwise healthy individuals. Cryptoglandular origin.

Anorectal Abscess

Anorectal Abscess Half of the anal glands originate in the intersphincteric plane, drain at the level of the dentate line. Ductal obstruction leads to stasis, infection, and abscess formation within the intersphincteric plane. Once an abscess develops, spreading may occur in multiple directions. Drainage of the abscess in 2/3 of cases will eventuate in a chronic fistula in ano.

Anorectal Abscess Most common is perianal (43%-58%). Presentation: 2-3 days of progressive pain, swelling, fever, tachycardia, sepsis.

Anorectal Abscess An ischiorectal abscess usually presents as a large tender fluctuant mass of the buttock, but will occasionally demonstrate only unilateral tenderness and asymmetry of the buttocks without fluctuance. Needle aspiration may confirm diagnosis.

Anorectal Abscess Patients with intersphincteric or supralevator abscess are more likely to present with fever, and may complain of anal pain, rectal pain, gluteal pain , yet no obvious abnormality will be found on exam. A tender mass may be felt on digital rectal exam, if tolerated.

Management Surgical drainage. A submucosal or intersphincteric abscess should be drained intrarectally to prevent the creation of a fistula. A supralevator abscess may need to be drained by CT guided drainage or transabdominal drainage if inaccessible thru the perineum.

Fistula-in-ano Abnormal communication between perianal skin and anal canal or rectal lumen. 90% of cryptoglandular origin, most are preceded by surgical or spontaneous drainage of an abscess.

Fistula in Ano

Classification Type I – Intersphincteric (70%) Type II- Transsphincteric (23%) Type III- Suprsphincteric (5%) Type IV- Extrasphincteric (2%)

Exam Under Anesthesia Goal is to identify the external, internal openings, the course of the tract, presence of secondary connections, presence of other rectal disease.

Exam Under Anesthesia Scope placed in such a way as to view the known or predicted location of the internal opening. A curved probe is gently introduced and guided to the internal opening. Occasionally you can pass it the other way. Can place small catheter into external opening and flush with methelyne blue, peroxide, sterile milk, or air. Identification successful in 86%.

Goodsall’s Rule

Fistula Management Goal is to abolish the primary fistula, secondary tracts, prevention of fistula recurrence, preservation of continence.

Fistula Management Management depends on the anatomy of the fistula. If it is apparent that the fistula is simple, and low, and the location of the internal opening can be inferred by probing, fistulotomy can be performed over the probe thru the predicted site of the internal opening at the dentate line. The entire tract is opened along its length. This should be reserved for low intersphinteric fistulae, which are short, posterior, and in which the external sphincter is not involved.

Fistula Management Fistulotomy should be avoided anteriorly, especially in women. Anal fistulae that involve a large portion of the external sphincter are considered complex, as are multiple fistulae, IBD patients, impaired preoperative continence. These may require use of a seton.

Seton Fistulotomy Fistulotomy is accomplished gradually. The muscle contained in the seton is slowly divided due to pressure necrosis, with the divided ends separating only minimally because of the fibrosis that develops behind the seton. An elastic seton (vessel loop) is drawn thru the tract a loosely secured to itself, tighten sequentially over time. Repeat every two weeks until division of the muscle is complete.

Rectal Prolapse