Nephrolithotomy, percutaneous

It is clear from each of these tables that open surgery is more successful than percutaneous nephrolithotomy (93 versus 87 per cent for small stones, 73 versus 69 per cent for large stones), irrespective of the size of the kidney stone. 

Conradie, J.P. Fluoroscopy based needle positioning system for percutaneous nephrolithotomy procedures. PhD Dissertation, Stellenbosch Stellenbosch University (2008)... 

Under general anesthesia a percutaneous track is made into the collecting system in the same way as for a percutaneous nephrolithotomy. A guidewire and catheter are passed up to the kidney at cystoscopy and retrograde injection of contrast medium is used to distend the PC system. A calix is chosen that will allow the best endoscopic approach, without the track passing through tumor. 

A 79-year-old woman, who had been taking phenytoin for 10 years, developed a fever and seizures and was found to have a right pelvic kidney with hydronephrosis and multiple large calcifications. Urinary stones were removed by percutaneous nephrolithotomy and contained the phenytoin metabolite 5-(para-hydroxyphenyl)-5-phenylhydantoin (35%) and proteinaceous material (65%). 

Other procedures such as percutaneous nephrolithotomy or ureteroscopy that allow the removal of ureteral stones are also kidney-protective (Durkey 2006) and constitute good alternatives to open surgery. However, the latter is still required in a considerable proportion of pediatric patients, primarily in those with urinary tract anomalies (El-Da manhoury et al. 1991). 

Endurology is minimally invasive therapy involving the urinary tract. It is the natural evolution of techniques developed for treatment of renal obstruction using percutaneous access. Access to the collecting system is via a puncture identical to that used in placement of percutaneous nephrostomy. Sequential dilatation of the track allows for placement of an introducer sheath that allows for the endosurgical treatment of a variety of conditions. Endourologic procedures include ureteral dilatation, ureteral stenting, calculus removal (percutaneous nephrolithotomy), and endopyelotomy (percutaneous pyelo-plasty). 

The fundamental techniques of nephrostomy insertion, track dilatation, and stent insertion have led to the development of more sophisticated endou-rologic procedures. The initial percutaneous technique developed was for removal of renal calculi. Within a short time, techniques for treatment of ureteropelvic junction and ureteral strictures were developed. Today percutaneous nephrolithotomy has been replaced in many situations by extracorporeal shock wave lithotripsy (ESWL) and uretero-scopic techniques. However, nonoperative management of staghorn calculi, infected lower pole calculi, or cystine stones via percutaneous nephrolithotomy and lithotripsy is still indicated. 

Contraindications to percutaneous nephrolithotomy are infrequent, but include a child with an uncorrectable coagulopathy. Children with a small renal pelvis cause technical problems. Renal access maybe difficult, and there maybe insufficient room to maneuver instruments if the collecting system is not large enough. Also, in small children, the size of the kidneys may make dilation to greater than 10-12 French dangerous for fear of a renal fracture. 

Percutaneous nephrolithotomy is performed under fluoroscopic guidance. In most cases, single plane, C-arm fluoroscopy is adequate. However, in some instances, biplane fluoroscopy is useful. 

The location and size of the renal calculi are initially determined by excretory urography, US, or CT. Prior to the procedure, an abdominal radiograph is obtained to confirm the presence of the stone. The most important factor for successful percutaneous nephrolithotomy is appropriate placement of the nephrostomy track. A posterolateral puncture of a middle calyx is preferred so that a direct route to the ureter is obtained and an effective tamponade achieved to limit bleeding. The target calyx depends on the location of the calculus. 

The excellent results with nephrolithotomy in adults (Ball et al. 1986 Boddy et al. 1987 Hulbert et al. 1985) led to its application in children. While in the reported pediatric series most children were over 5 years of age, percutaneous stone removal in younger children has been successful (Ball et al. 1986). The percutaneous approach has been especially useful in managing recurrent renal calculi in children who have had multiple open surgical procedures. 

Boddy SAM, Kellett MJ, Fletcher MS et al (1987) Extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy in children. J Pediatr Surg 22 223-227... 

Hulbert JC, Reddy PK, Gonzales R et al (1985) Percutaneous nephrolithotomy an alternative approach to the management of pediatric calculus disease. Pediatrics 76 610-612... 

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