Key Difference – Nephrostomy vs Urostomy
Let us first look at the meaning of the term ‘stoma’ before analyzing the difference between Nephrostomy and Urostomy. A stoma is an opening, either natural or surgically created, which connects a body cavity to the external environment. A nephrostomy is an artificially created opening between the kidney and the skin of the back which allows for the urinary diversion (flow of urine by passing the normal passage through ureters) directly from the upper part of the urinary system (renal pelvis). A urostomy is a somewhat similar procedure performed more distally along the urinary system (usually from the urinary bladder) to provide the urinary diversion. A urostomy is created for urinary diversion in situations where drainage of urine from the bladder and urethra is not possible, e.g. in the case of obstruction. The key difference between nephrostomy and urostomy is that nephrostomy is created between the renal pelvis and the skin on the back whereas urostomy is created between the urinary bladder / lower ureters and the skin on the lower abdomen. However, urostomy sometimes generally refers to any connection between the urinary tract and the exterior which includes nephrostomy as well.
What is Nephrostomy?
Nephrostomy is an artificial connection between the upper part of the urinary tract and the skin on the back created surgically to facilitate the flow of urine in the presence of a distal obstruction to the urinary tract. Generally, a hole is created under anesthesia using surgical instruments. Then the hole is enlarged using dilators. This is done under ultrasonic guidance. Then a pigtail catheter is inserted between the renal pelvis and the exterior. This will allow free flow of urine by passing a distal obstruction. The external end of the catheter is usually connected to a collecting bag. This procedure is done in the case of urinary stone disease, which causes complete obstruction or renal abscess, a malignancy causing ureteric obstructions. This procedure helps to protect the remaining renal tissue from further damage. This is usually done as an emergency procedure. Once the distal obstruction is relieved, the nephrostomy can be removed. Common complications of the procedure are accidental renal puncture causing lot of bleeding, rupture of the renal pelvis and the displacement and blockage of the pigtail catheter. Patency of the catheter can be tested by a die test which is usual in the case of obstructions.
What is Urostomy?
Urostomy is usually created between the urinary bladder or lower ureters and the skin on the lower abdomen. This procedure is quite different, and the ureters are directly opened to the outside or part of the bowel is used to create the stoma. Then the stoma is covered with a collecting bag. Sometimes an internal pouch is surgically created to collect urine using a part of the bowel when the bladder is removed during the surgery such as in bladder carcinoma. This procedure is done in situations like infiltrating prostatic or bladder carcinoma, urethral injury. Complications of the procedure include bladder injury and cystitis.
What is the difference between Nephrostomy and Urostomy?
Characteristics of Nephrostomy and Urostomy:
Nephrostomy: Nephrostomy is created between the renal pelvis and the skin on the back.
Urostomy: Urostomy is created between the urinary bladder / lower ureters and the skin on the lower abdomen.
Nephrostomy: The pigtail catheter is used for urinary drainage.
Urostomy: The distal end of the ureters or part of the bowel is sutured to the skin forming the stoma.
Nephrostomy: Nephrostomy can cause accidental renal puncture and bleeding, rupture of the renal pelvis and the displacement and blockage of the pigtail catheter.
Urostomy: Urostomy can lead to internal organ damage injury and infections, sexual dysfunction and skin related complications such as itching.
Nephrostomy: Nephrostomy is done to relieve upper urinary tract obstructions such as stone disease causing complete obstruction or renal abscess, malignancy causing urinary obstructions.
Urostomy: Urostomy is done to relieve lower urinary tract obstructions such as infiltrating prostatic or bladder carcinoma, urethral injury causing bladder outlet obstructions.Image Courtesy: “N01224 H nephrostomy” by Unknown (Public Domain) via Commons “Diagram showing how a urostomy is made (ileal conduit) CRUK 124″ by Cancer Research UK – Original email from CRUK. (CC BY-SA 4.0) via Wikimedia Commons