STONE DISEASE

Percutaneous nephrolithotomy for caliceal diverticular calculi: a novel single stage approach
Kim SC, Kuo RL, Tinmouth WW, Watkins S, Lingeman JE
Methodist Hospital Institute for Kidney Stone Disease, Indiana University School of Medicine, Indianapolis, Indiana, USA
J Urol. 2005; 1734: 1194-8

• Purpose: Current percutaneous treatment of symptomatic caliceal diverticular calculi involves renal access, stone removal, dilation of the diverticular communication, fulguration of the cavity and placement of a nephrostomy tube. We reviewed the outcomes of patients undergoing a novel single stage percutaneous nephrolithotomy technique for radiopaque caliceal diverticular stones that eliminates ureteral catheterization and entry into the renal collecting system.
• Materials and Methods: A total of 21 patients (8 male and 13 female including 1 bilateral) with a mean age of 42.4 years underwent percutaneous nephrolithotomy for caliceal diverticular stones from February 2001 to May 2003. Of the diverticula 12 were upper pole, 4 were interpolar and 6 were lower pole. Infracostal access was established by the urologist directly onto the radiopaque stones without the aid of a ureteral catheter. After balloon tract dilation a 30Fr Amplatz sheath was placed and following stone removal the diverticulum was fulgurated. The infundibulum was neither cannulated nor dilated. A 20Fr red rubber catheter or an 8.5Fr Cope loop was placed into the diverticulum. Stone-free status was assessed by noncontrast computerized tomography on postoperative day 1 (POD1). The drainage tube was removed if there was no urine drainage and the kidney was stone-free. Excretory urography was performed at 3 months to evaluate diverticular resolution.
• Results: Of 21 patients 20 were discharged home tubeless on POD1 and 18 of 21 (85.7%) renal units were stone- free on POD1 noncontrast computerized tomography. Mean operative time was 58.5 minutes and mean stone burden was 138.9 mm. Mean stone diameter was 11.6 mm and mean diverticular diameter was 15.3 mm. Of 22 renal units 16 had followup excretory urography. All diverticula decreased in size and 14 (87.5%) had complete resolution.
• Conclusions: In patients with symptomatic radiopaque caliceal diverticular stones, a single stage procedure without the need for ureteral catheterization combined with direct infracostal diverticular puncture allows for a rapid procedure with little morbidity.
  
  
• Editorial Comment
  A variety of minimally invasive treatment options is available for the treatment of stone-bearing caliceal diverticula, including SWL, ureteroscopy, PCNL and laparoscopy. Among these, the percutaneous approach has been shown to offer the most consistent stone-free, symptom-free and diverticulum-free results. However, there is no consensus as to the optimal technique for management of the diverticulum or the diverticular neck. While most investigators recommend fulguration of the diverticulum, some additionally advocate identification and treatment of the diverticular neck with dilation or endoincision to assure drainage from a persistent diverticular cavity in the event ablation fails. Others, however, feel that treatment of the cavity is sufficient and recommend no treatment of the neck, since treatment adds time and risk to the procedure, primarily by way of bleeding, and generally necessitates placement of a transdiverticular drainage tube for a few days to a week to assure a patent tract.
  Although outcomes with the various percutaneous approaches have been excellent, Kim and colleagues challenge the need for additional retrograde access to facilitate identification and treatment of the diverticular neck by advocating simple subcostal access to the diverticulum, fragmentation/removal of the stone and fulguration of the cavity without addressing the diverticular neck. With this approach, a stone free rate of 86% was achieved, and in 88% of cases the diverticulum resolved completely or was reduced in size. This approach has the advantage of avoiding a supracostal approach in most cases of upper pole diverticula since access into the collecting system is not necessary and consequently a cephalad-directed access tract, below the 12th rib, will provide adequate access to the diverticulum. Although symptomatic outcomes were not addressed in this study, it is probably safe to assume that at least the 88% of patients rendered stone free and in whom the diverticulum resolved are symptom-free. Of note, the key to the success of these difficult cases is in the access. Provided the stone is visible to provide a target for percutaneous puncture, this approach can be successful. However, in some cases the diverticulum is difficult to identify fluoroscopically without the aid of retrograde instillation of contrast to opacify the diverticulum, in which case, a ureteral catheter or occlusion balloon can be a welcome aid.

Dr. Margaret S. Pearle
Associate Professor of Urology
University of Texas Southwestern Med Ctr
Dallas, Texas, USA