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Percutaneous nephrolithotomy for kidney stone removal
A minimally invasive option to treat this common occurrence in pets


Surgical-assisted nephroscopic lithotripsy

Surgical-assisted nephroscopic lithotripsy is performed by using a rigid endoscope during an open laparotomy, resulting in excellent magnification of the renal pelvis for stone retrieval. The same procedure as above (PCNL) can be performed via laparotomy rather than percutaneously, termed nephroscopic guided lithotripsy.

The greater curvature of the kidney is punctured with a renal puncture needle, and a pyelogram is performed. A guide wire is then advanced into the renal pelvis with fluoroscopic guidance, and a balloon dilation catheter, preloaded with a matching sheath, is advanced over the wire and onto nephrolith. The balloon is dilated, and the sheath slides right over the balloon with a smooth transition. The balloon is withdrawn, and the scope is inserted through the sheath for stone removal.

Little risk of hemorrhage exists when using a balloon-sheath combination since this creates a tamponade effect, and the renal parenchyma is spread apart with the balloon, not cut with a scalpel blade, making renal damage dramatically less then that with a nephrotomy. If this is done surgically, then a nephrostomy tube is not necessary because the hole can be closed by directly suturing the renal capsule to prevent leakage. Because a balloon is used to dilate the renal parenchyma, minimal nephron loss occurs, and the tissue is compressed via balloon dilation rather than being incised. This is now being performed routinely on canine kidneys in our practice and has been highly successful.

Figure 4
Unlike a nephrotomy, these minimally invasive procedures do not require transient occlusion of renal vessels and result in a much smaller hole in the renal parenchyma than a nephrotomy. Placing sutures in the capsule and apposing the small incision can close the renal access point. Care must be taken to assess all areas of the renal pelvis and renal calyces, as small calculi can remain if fluoroscopy and contrast nephrography are not used concurrently. We recommend concurrent fluoroscopy, as is recommended in human urology (Figure 3).

After the procedure, a ureteral stent is placed to protect the ureter from any small fragments that could an obstruction (Figure 4). This stent is then removed four to six weeks later cystoscopically.

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Recommended reading

• Raza A, Turna B, Smith G, et al. Pediatric urolithiasis: 15 years of local experience with minimally invasive endourological management of pediatric calculi. J Urol 2005;174(2):682-685.

• Donner GS, Ellison GW, Ackerman N, et al. Percutaneous nephrolithotomy in the dog: An experimental study. Vet Surg 1987;16(6): 411-417.

• Al-Shammari AM, Al-Otaibi K, Leonard MP, et al. Percutaneous nephrolithotomy in the pediatric population. J Urol 1999;162(5):1721-1724.

• Lennon GM, Thornhill JA, Grainger R, et al. Double pigtail ureteric stent versus percutaneous nephrostomy: effects on stone transit and ureteric motility. Eur Urol 1997;31(1):24-29.

Dr. Berent is the director of Interventional Endoscopy Services in the Department of Diagnostic Imaging at The Animal Medical Center in New York City. Dr. Weisse is the director of Interventional Radiology Services in the Department of Diagnostic Imaging at The Animal Medical Center in New York City.

For a complete list of articles by Drs. Berent and Weisse, visit


Source: DVM360 MAGAZINE,
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