Rectal prolapse (RP) is a condition where the rectum, the final section of the large intestine, descends and telescopes through the anus. This descent of tissue through the anal opening can be a source of significant discomfort and concern. While the primary symptoms involve the anal area, a frequently unrecognized consequence of this condition is lower back pain. This article explores the specific ways in which rectal prolapse can lead to persistent lower back pain.
Understanding Rectal Prolapse
Rectal prolapse is a structural defect in which the rectum loses its normal attachments within the pelvis and pushes outward. Partial or mucosal prolapse occurs when only the lining (mucosa) of the rectum protrudes through the anus. This is often an early stage and can be confused with hemorrhoids because it only involves the innermost layer of tissue.
The more severe form is complete, or full-thickness, prolapse (sometimes called procidentia), where the entire wall of the rectum slides out through the anal opening. This descent can become a chronic issue that requires manual reduction or surgical correction. A related condition is internal prolapse, or intussusception, where the rectum telescopes in on itself but does not exit the anus.
The Mechanism Linking Prolapse and Back Pain
The connection between rectal prolapse and lower back pain is anatomical. The pain is typically mechanical and referred, meaning it originates from one area but is perceived in another. The constant downward pressure of the prolapsed tissue strains the muscles and ligaments that support the rectum and pelvic organs.
These supporting structures, particularly the pelvic floor muscles like the levator ani, are anchored directly to the tailbone and sacrum, which forms the base of the spine. Chronic strain on the pelvic floor from the prolapse can lead to muscle fatigue and spasm, which is perceived as persistent, dull lower back or perineal pain.
Furthermore, the physical displacement of the rectum can place tension on the sacral nerves that pass near the rectum and supply sensation to the lower back and pelvis. Irritation of these shared nerve pathways can cause pain signals to travel to the lower back, resulting in discomfort that may not respond to typical back pain treatments.
Recognizing Common Accompanying Symptoms
Since lower back pain is often a secondary or referred symptom, recognizing the primary indicators of rectal prolapse is important for an accurate diagnosis. The most noticeable sign is the feeling of a reddish, bulging mass protruding from the anus, especially during a bowel movement or while straining. In the early stages, this mass may spontaneously retract back inside.
Patients also frequently experience difficulty controlling bowel movements, known as fecal incontinence, due to the stretching and weakening of the anal sphincter muscles. Another common symptom is tenesmus, which is the persistent feeling of incomplete evacuation even after passing stool. There may also be leakage of mucus or blood from the rectum due to irritation of the exposed tissue.
A feeling of pressure or fullness in the rectum is a common complaint. A clinician will often ask the patient to strain during an examination to visualize the protrusion and confirm the diagnosis.
Managing and Treating Rectal Prolapse
Conservative Management
For mild cases, particularly internal or mucosal prolapse, conservative management is often the first step. This includes dietary changes to increase fiber and fluid intake, and the use of stool softeners to prevent straining during defecation.
Surgical Correction
When the prolapse is complete, or if conservative measures fail, surgical repair is typically necessary for lasting resolution. Surgical options include abdominal procedures, like rectopexy, which fix the rectum to the sacrum using sutures or mesh, and are associated with a lower recurrence rate. Perineal procedures are performed through the anus and are generally less invasive, making them suitable for older or less healthy patients. Successful surgical correction resolves the mechanical strain on the pelvic floor and sacral nerves, which usually alleviates the associated lower back pain.