A ureteral stent is a thin, hollow tube placed inside the ureter, the tube connecting the kidney to the bladder. The primary purpose of this device is to ensure the free flow of urine when the ureter is blocked or damaged, most commonly due to kidney stones. The presence of the stent prevents urine from backing up into the kidney, which can cause swelling and potentially lead to permanent damage. Stents are temporary devices used to allow the ureter to heal following a surgical procedure or bypass an obstruction.
What is a Ureteral Stent and Where is it Located?
The ureteral stent is a flexible tube that spans the entire length of the ureter. To keep it secure and prevent migration, the stent has a coil, or pigtail, at both ends: one rests within the kidney and the other inside the bladder. The stent creates a continuous passage for urine drainage, bypassing any obstruction.
To understand how the stent affects bowel function, it is important to consider the anatomy of the abdominal and pelvic cavity. The ureters are located in the retroperitoneal space, situated behind the abdominal lining, placing them in close proximity to the colon. Specifically, the lower ureter and the bladder are near the sigmoid colon and the rectum.
The proximity of the stent’s coiled end in the bladder to the rectum means that any irritation or pressure exerted by the stent can affect these neighboring organs. This anatomical relationship establishes a physical mechanism for interaction between the urinary and digestive systems.
The Causes of Constipation During Stent Placement
Constipation is a common side effect after ureteral stent placement, caused by two distinct mechanisms. The first involves the direct physical effects of the stent itself, which can cause localized inflammation or irritation in the bladder and lower ureter.
Because the ureter and bladder share nerve pathways with the gastrointestinal tract, this irritation can trigger somatic-visceral reflexes. These reflexes slow down peristalsis, the normal movement of the colon muscles, leading to reduced bowel motility and constipation. The action of the bladder filling and contracting, which is amplified by the stent’s presence, can also place physical pressure on the rectum, sometimes creating a sensation of needing to pass stool.
The second, and often more significant, cause is the pharmacological effect of necessary post-procedure pain medication. Many patients receive opioid pain relievers to manage discomfort, and these powerful medications are well-known for slowing down the movement of the entire digestive tract.
Opioids slow peristalsis and reduce fluid secretion in the gut lining. This causes stool to remain in the colon longer, allowing more water to be absorbed and resulting in hard, dry bowel movements. This drug-induced effect, combined with the physical irritation from the stent, creates a highly constipating environment.
Strategies for Bowel Management While Stented
Managing bowel function while a ureteral stent is in place requires a multi-pronged approach, starting with hydration being the first line of defense. Drinking plenty of fluids, aiming for at least two liters daily, helps flush the urinary system to reduce stent irritation. Adequate fluid intake also keeps stool soft and easier to pass.
Dietary modifications are also highly effective in promoting regularity. Increasing high-fiber foods, such as fruits, vegetables, and whole grains, adds bulk to the stool and stimulates bowel movement. Consuming warm liquids, like prune juice, can provide a natural laxative effect that aids motility.
If dietary changes are insufficient, over-the-counter medications can prevent or treat constipation, though consulting a healthcare provider before starting any regimen is advisable. Stool softeners, such as docusate sodium, work by allowing water to penetrate the stool, making it softer. Osmotic laxatives, like polyethylene glycol, draw water into the colon, increasing the stool’s water content.
Stimulant laxatives should generally be avoided unless recommended by a physician, as they can cause cramping mistaken for stent-related pain. Utilizing these strategies proactively, especially while taking opioid pain medication, significantly reduces the risk and severity of constipation.