Related Experiment Video
Updated: Jul 5, 2026

Transmesenteric Laparoscopic Pyeloplasty in Trendelenburg Position for Horseshoe Kidney with Hydronephrosis
Published on: July 8, 2025
Drainage characteristics and differential function of the horseshoe kidney: what is typical?
Benjamin R Stockton1, Daniel A Pryma, Marc C Smaldone
1Department of Urology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA.
Purpose:
To describe the drainage and differential function of the horseshoe kidney.
Patients And Methods:
A retrospective review of mercaptoacetyltriglycine (MAG3) nuclear renograms from 1991 to 2007 was performed. Nineteen patients with horseshoe kidney who had not undergone previous renal surgery were identified. All studies were reviewed, and patient information was gathered. Drainage characteristics and differential function were determined.
Results:
Nineteen primary MAG3 studies were found, representing 38 evaluable renal units. For these units altogether, the median t1/2 was 11 minutes. A t1/2 of 10 minutes or less was found in 18 units (47%), while 12 units (32%) showed a t1/2 longer than 20 minutes. The relative function difference mean was 24.6%. The number of patients with a relative function difference greater than 10% was 11 (57%), and those with a relative function difference greater than 20% was 7 (37%).
Conclusion:
Horseshoe kidney is associated with fairly high rates of poor renal drainage and elevated differential function.
Related Concept Videos
Kidney Structure
Filtration and Urine Formation
Renal Tubule and Collecting Duct
Proximal Convoluted Tubule (PCT):
The PCT is the initial segment of the renal tubule, extending from the Bowman's capsule that encloses the glomerulus. Its convoluted structure and microvilli-lined cells increase the surface area for reabsorption. The PCT reabsorbs glucose, amino acids, sodium, and water from the filtrate, ensuring essential...
Nephrons
Physiology of the Genitourinary System II: Tubular Reabsorption and Secretion
Internal Anatomy of the Kidney
Anatomical Position and Dimensions
The kidneys are retroperitoneal organs positioned against the posterior abdominal wall on either side of the spine, roughly between the twelfth thoracic and third lumbar vertebrae. Each kidney is typically 10-12 cm long, 5-6 cm wide, and 3-4 cm thick, weighing about 150 grams.
Renal Cortex
The outermost region of the kidney is the...

