A back injury can impact bowel movements. The spinal column and its intricate nerve network regulate many bodily functions, including digestion and waste elimination. Damage to these nerves can disrupt bowel function, a condition known as neurogenic bowel dysfunction. This article explores the relationship between back injuries and bowel function, specific conditions, and important symptoms to recognize.
How Back Injuries Impact Bowel Function
The digestive system’s control relies on a complex interplay between its intrinsic nervous system, known as the enteric nervous system (ENS), and the central nervous system (CNS) through the autonomic nervous system. The ENS, often called the “second brain,” is embedded within the gastrointestinal tract lining and can operate independently, but it communicates with the brain and spinal cord via parasympathetic and sympathetic pathways. Specifically, the vagus and pelvic nerves carry signals between the ENS and the CNS.
Nerves branching from the spinal cord, particularly in the lower back (lumbar) region, control the muscles and sensations necessary for proper bowel function, such as the ability to feel when the bowel is full and to control the anal sphincter. Damage, compression, or irritation to these spinal nerves can disrupt these important signals, leading to what is termed neurogenic bowel dysfunction. This disruption can manifest as issues with stool movement through the colon, altered sensation, or problems with sphincter control.
Back Conditions Linked to Bowel Changes
A herniated disc, where the soft inner material of a spinal disc protrudes and presses on nearby nerves, can disrupt the signals regulating bowel movements. This compression can result in symptoms like constipation, diarrhea, or difficulty controlling bowel movements.
Spinal stenosis, a narrowing of the spaces within the spinal canal, can also compress the spinal cord or nerve roots, leading to bowel control issues in more severe instances. Lumbar spinal stenosis, affecting the lower back, is particularly associated with such problems.
Spinal cord injury (SCI) is a common cause of neurogenic bowel, where the interruption of neural pathways between the brain and bowel results in reduced or no control over defecation. Depending on the level of injury, SCI can lead to either a “reflex” (spastic) bowel, where the anal sphincter remains tight but uncontrolled movements can occur, or a “flaccid” bowel, characterized by a loose sphincter and potential leakage.
Cauda equina syndrome (CES) is a particularly serious condition where the bundle of nerves at the lower end of the spinal cord (the cauda equina) becomes compressed. This compression can severely interrupt nerve signals to the bladder, bowel, and legs, leading to significant dysfunction. CES can cause both constipation and fecal incontinence, along with a loss of sensation in the rectal area.
Recognizing Urgent Symptoms
When a back injury is accompanied by changes in bowel function, certain symptoms are considered “red flags” that require immediate medical attention. Sudden onset of bowel incontinence, meaning an inability to control bowel movements, is an important sign. This can range from minor leakage to complete loss of control and often occurs alongside bladder dysfunction. Severe constipation or an inability to have a bowel movement at all, especially if new and unexplained after a back injury, also warrants prompt evaluation.
Another significant warning sign is “saddle anesthesia,” which refers to numbness or loss of sensation in the groin, genital area, buttocks, and inner thighs—the areas that would touch a saddle. These symptoms, particularly when combined with severe low back pain, leg weakness, or altered sensation in the legs, strongly suggest a serious underlying condition like cauda equina syndrome. Delays in seeking medical care for these “red flag” symptoms can lead to permanent nerve damage and lasting problems with bowel and bladder control. Emergency medical assessment, often involving an MRI, is necessary to diagnose and manage such urgent situations.
Addressing Bowel Dysfunction
Managing bowel dysfunction stemming from a back injury typically begins with a thorough medical diagnosis. Healthcare providers will gather a detailed health history and conduct a physical examination, which may include a digital rectal exam to assess sphincter strength and sensation. Imaging studies such as MRI or CT scans of the spine are often important for identifying the source of nerve compression or damage. Specialized tests like anorectal manometry, which measures muscle pressure, or colonic transit studies, which assess stool movement, may also be performed.
Once a diagnosis is established, treatment approaches focus on managing the bowel issues and, when possible, addressing the underlying back injury. Lifestyle modifications are often a first step, including dietary changes to adjust fiber and fluid intake, and establishing a regular bowel emptying schedule. Medications such as laxatives, stool softeners, or bulking agents may be prescribed to help regulate bowel movements.
Bowel management programs can involve techniques like digital rectal stimulation or transanal irrigation, which introduces water into the rectum to aid evacuation. In some instances, nerve stimulation using a small implantable device can help control bowel function. If the bowel dysfunction is caused by severe nerve compression from a back injury, such as a herniated disc or spinal stenosis, surgical intervention to decompress the nerves may be considered. This aims to relieve pressure and potentially restore nerve function, thereby improving bowel control.