Effects of horizontal versus vertical bolster alignment on anatomical orientation of kidney as applied to prone percutaneous nephrolithotomy.

Horizontal bolsters provide significantly more caudal displacement of the kidneys; the right kidney being displaced more as compared to the left. However, there is also an increase in the skin-calyceal distance with horizontal as compared to the vertical bolsters. These assessments may help the surgeons decide optimal bolster position individualized to the patient.