Lower pole anatomy and mid-renal-zone classification applied to flexible ureteroscopy: experimental study using human...

Area of Science:

• Urology
• Anatomy
• Medical Imaging

Background:

• Flexible ureteroscopy is a minimally invasive procedure for treating upper urinary tract pathologies.
• Understanding the detailed anatomy of the kidney collecting system is crucial for successful ureteroscopic interventions.
• The inferior pole collecting system presents unique anatomical challenges during ureteroscopy.

Purpose of the Study:

• To analyze the anatomy of the inferior pole collecting system.
• To evaluate the utility of a mid-renal-zone classification in human kidney endocasts.
• To apply these anatomical findings to the context of flexible ureteroscopy.

Main Methods:

• Utilized 170 three-dimensional polyester resin endocasts of the kidney collecting system from adult cadavers.
• Classified endocasts into four groups (A1, A2, B1, B2) based on mid-renal-zone drainage patterns.
• Measured the number of calices, and specific angles (LIICA) related to the inferior pole collecting system.

Main Results:

• The majority of kidneys (49.41%) had four or more calices draining the inferior pole.
• Specific drainage patterns (A1 and B1) were most prevalent, accounting for over 68% of cases.
• No statistically significant differences in the studied angles (LIICA) were found across the classification groups.

Conclusions:

• Collector systems where the kidney midzone is drained by minor calices dependent on superior or inferior caliceal groups exhibit restrictive anatomical features.
• The proposed mid-renal-zone classification is predictive of anatomical risk factors.
• This classification can aid in anticipating and managing potential difficulties during lower pole flexible ureteroscopy.