Rectal prolapse, a condition centered in the pelvis, can cause both localized and referred back pain. This occurs because the rectum and the lower spine share an intricate network of muscles, ligaments, and nerves. A physical problem in one area often affects the other, and understanding the mechanical impact of prolapse helps explain this connection.
Defining Rectal Prolapse
Rectal prolapse is a condition where the rectum, the final section of the large intestine, slides out of its normal position and protrudes through the anus. It is classified into types based on the extent of the protrusion. A full-thickness (complete) prolapse involves the entire rectal wall extending outside the body, appearing as a larger, reddish mass. A partial (mucosal) prolapse involves only the inner lining of the rectum and is typically smaller.
The condition is most common in women over 60, but it can affect people of any age. It is often linked to chronic constipation and excessive straining during bowel movements. The most noticeable symptom is the feeling of a lump or swelling coming out of the anus, especially after a bowel movement, coughing, or sneezing. Other symptoms include the sensation of incomplete evacuation, the need to strain, and the leakage of mucus or stool. While the prolapse itself may not be painful, the chronic irritation and associated muscular issues frequently lead to discomfort in the lower abdomen or pelvis.
How Prolapse Causes Referred and Localized Back Pain
The connection between rectal prolapse and back pain is primarily anatomical, involving the pelvic floor structures and shared nerve pathways. The pelvic floor is a complex sling of muscles and ligaments that supports the pelvic organs and attaches directly to the coccyx (tailbone) and sacrum (lower spine). When the rectum prolapses, it creates significant, abnormal tension and mechanical drag on these supporting structures. This constant physical presence, especially in a full-thickness prolapse, chronically strains the pelvic floor muscles.
These muscles can become tense and go into spasm, often manifesting as pain in the lower back or tailbone region (coccydynia). Because the pelvic floor muscles attach to the lower spine, their persistent tightness pulls on these bony anchors, causing localized discomfort.
Back pain associated with prolapse is often referred pain, where the source of the problem and the location of the pain differ. The pelvis and lower back share common neural pathways, including the sacral and pudendal nerves. Pressure or irritation on these nerves from the displaced rectal tissue or tense muscles sends pain signals interpreted as originating in the buttocks, hips, or lower lumbar area.
The chronic straining required to empty the bowels further exacerbates the problem by increasing intra-abdominal pressure and stressing the weakened pelvic floor. This repeated physical effort and resulting muscle fatigue contribute to generalized lower back and pelvic pressure. The mechanical displacement and muscular tension combine to create a persistent source of pain.
Treatment and Resolution of Pain
Treating the underlying rectal prolapse is the most effective method for resolving associated back and pelvic pain. Initial management focuses on non-surgical methods aimed at reducing straining. These include dietary changes to increase fiber and fluid intake to soften stool. Pelvic floor physical therapy may also be recommended to help relax or strengthen the surrounding muscles, alleviating tension.
For advanced or persistent cases, surgical intervention is required to secure the rectum back into its correct anatomical position. The two main approaches are abdominal procedures, such as rectopexy, and perineal procedures performed through the anus. Rectopexy involves attaching the rectum to the sacrum (lower backbone) using sutures or mesh to reinforce its position.
Successful surgical repair directly addresses the mechanical cause of the back pain by removing the physical drag and chronic strain. When the rectum is properly anchored, the abnormal tension on the sacrum and coccyx is relieved. This allows irritated nerves and spastic muscles to relax, leading to a significant reduction or complete disappearance of the secondary back and pelvic discomfort.