To the Editor:
T
raditional fluoroscopic-guided two-stick nephrostomy placement involved contrast injection from a small needle to confirm access into the collecting system followed by air to optimize visualization of the posterior calices in the prone patient. Struggles with extravasated contrast and difficulty with fluoroscopic visualization of stones during percutaneous nephrolithotomy access acquisition with contrast led our radiologist to suggest using air as the primary contrast agent in these cases. Currently, we use air to perform retrograde pyelography in all our percutaneous nephrolithotomies. Contrast is only injected from the needle when there is a question of whether it is within the collecting system. This positive contrast agent injection is safe in the event of venous access and also is easily seen in the setting of negative air contrast. The mixture of the two contrast techniques ultimately complements each one when trying to problem solve during access acquisition.
