The medical term for the stricture or narrowing of the rectum is Rectal Stricture or Rectal Stenosis. This condition describes an abnormal reduction in the diameter of the rectal lumen, the hollow passageway through which stool must pass to exit the body. The narrowing itself can present a partial or, in severe cases, a complete obstruction to the normal movement of bowel contents. This constriction is often caused by the formation of stiff, inelastic scar tissue, known as fibrosis, within the rectal wall.
Underlying Reasons for Rectal Narrowing
The formation of scar tissue that leads to rectal narrowing is a secondary process, usually occurring as the body attempts to heal from a previous injury or chronic inflammation. A significant number of benign rectal strictures develop following surgical complications, particularly at the site of an anastomosis, where two ends of the bowel are surgically joined. This complication is the most common cause of benign narrowing, often occurring after surgery for conditions like rectal cancer or diverticular disease.
Chronic inflammatory conditions represent another major category of causes. Inflammatory bowel diseases (IBD), such as Crohn’s disease and Ulcerative Colitis, involve persistent inflammation that leads to repeated cycles of tissue injury and healing. This causes the deposition of fibrous tissue and subsequent narrowing of the rectal wall. Chronic proctitis, an inflammation specifically of the rectum, can also progress to stricture formation.
External medical treatments can also induce this scarring process. Radiation therapy directed at pelvic cancers, such as prostate or cervical cancer, causes radiation proctitis. This treatment creates late-stage damage characterized by inflammation and poor blood flow, which leads to excessive collagen deposition and fibrosis, resulting in a firm, non-elastic stricture.
Less frequently, the narrowing can be caused by conditions that reduce blood flow to the rectal tissue, leading to ischemia and subsequent tissue death and scarring. Malignancy is another cause, where the stricture is a mechanical obstruction created by the cancerous tumor itself growing into the lumen of the rectum.
Recognizing the Signs
The symptoms associated with rectal stricture arise directly from the difficulty the body has pushing stool through the constricted passageway. The most common complaint is dyschezia, or chronic difficulty and pain during defecation, which often leads to significant straining. As the opening narrows, patients often report a change in the physical appearance of their stool, which may become thin, pencil-like, or ribbon-like.
The inability to fully empty the bowels is another frequent sign, leading to a persistent feeling of incomplete evacuation. This partial obstruction can also cause secondary issues such as abdominal distention, cramping, and discomfort. In more advanced cases, the difficulty in passing stool can progress to obstipation, which is severe constipation with an inability to pass either stool or gas.
Initial assessment begins with a thorough review of the patient’s medical history, focusing on past surgeries, inflammatory conditions, or radiation treatments. A physical examination, including a digital rectal examination (DRE), allows a physician to manually assess the tightness of the anal canal and distal rectum.
If a stricture is suspected, further diagnostic steps are taken. Imaging tests such as X-rays or a computed tomography (CT) scan may be used to visualize the area and identify the location and extent of the obstruction. An endoscopic examination, such as a flexible sigmoidoscopy or colonoscopy, is often performed to directly view the stricture, measure its diameter, and obtain tissue samples (biopsies) to determine if the cause is benign or malignant.
Approaches to Corrective Treatment
The approach to correcting a rectal stricture is dependent on its cause, severity, and the patient’s overall health. For mild cases with minimal symptoms, management begins with non-surgical methods aimed at making stool softer and easier to pass. This involves increasing dietary fiber intake, using bulk-forming agents, and incorporating stool softeners or mild laxatives.
For clinically relevant strictures causing significant obstructive symptoms, the first-line invasive treatment is typically endoscopic dilation. This procedure involves passing a flexible endoscope to the site of the narrowing, and then using specialized balloon or rigid dilators to gently stretch and widen the constricted segment. The goal is to tear the inelastic scar tissue in a controlled manner, and repeated dilation sessions are often necessary to maintain the achieved opening.
In cases where dilation is unsuccessful or the stricture is dense, long, or complex, other endoscopic techniques may be employed. This can include injecting corticosteroids directly into the scar tissue to inhibit new collagen formation or using an electrocautery device to cut the fibrous ring before dilation. Stent placement, using temporary or permanent expandable mesh tubes, may be considered to physically keep the narrowed segment open, particularly for malignant strictures.
When non-surgical and endoscopic treatments fail, or if the stricture is caused by extensive malignancy or severe damage, surgical intervention becomes necessary. Procedures such as strictureplasty involve surgically incising the stricture longitudinally and then closing the incision transversely, which effectively widens the lumen without removing a bowel segment. If the narrowed segment is severely damaged, malignant, or fails to respond, a resection may be performed to surgically remove the strictured section and re-establish a healthy connection (anastomosis).