STONE DISEASE

Pain after percutaneous nephrolithotomy: impact of nephrostomy tube size
Pietrow PK, Auge BK, Lallas CD, Santa-Cruz RW, Newman GE, Albala DM, Preminger GM
Comprehensive Kidney Stone Center, Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
J Endourol. 2003; 17: 411-4

• Background and Purpose: Percutaneous nephrolithotomy (PCNL) is the procedure of choice for managing large renal calculi. Investigations have recently focused on reducing the morbidity of the procedure and improving postoperative patient comfort by using smaller endoscopic instruments. We sought to evaluate the effect of a smaller percutaneous drainage catheter on postoperative pain.
• Patients and Methods: Thirty consecutive patients were randomized to receive either a 10F pigtail catheter or a 22F Councill-tip catheter for their percutaneous drainage after PCNL. The demographics were similar in the two groups, as was the rate of supracostal access (47% v 43%, respectively). Self-assessed analog pain scores were collected at 6 hours postoperatively as well as on the morning of the first and second postoperative days (POD). Total narcotic usage was tabulated using morphine equivalents. Complications, including the change from baseline hematocrit, were reviewed.
• Results: There was no significant difference in the change in hematocrit (6.8 v 6.2 percentage points, respectively). Those patients with the smaller nephrostomy tube noted significantly lower pain scores at 6 hours (3.75 v 5.3; P = 0.03). Although the pain scores were lower on POD 1 and 2 for the 10F catheter group, the difference was not statistically different (1.9 v 2.9 and 1.25 v 1.9, respectively; both P > 0.05). The patients having the 10F catheter required fewer narcotics: 78 mg v 91 mg, although the difference was not statistically significant.
• Conclusion: The use of a small drainage catheter after PCNL is associated with lower pain scores in the immediate postoperative period, yet no statistically significant benefit to the patient with regard to comfort is demonstrated beyond 6 hours. In addition, there is a trend toward reduced narcotic requirements. Finally, there is no apparent increase in patient morbidity from the use of the smaller nephrostomy tubes.
  
  
• Editorial Comment
  Despite the uniformly high stone free rates achieved with PCNL irrespective of stone burden, stone location or stone composition, alternative therapies such as ureteroscopy and SWL continue to be advocated despite less successful outcomes because of the lower associated morbidity. Consequently, efforts to reduce the morbidity of PCNL primarily through alterations in tube management have been under way. Pietrow and colleagues performed a prospective, randomized trial of 30 patients undergoing PCNL who received either a 22F nephrostomy tube or a 10F pigtail catheter post-procedure and compared the 2 groups with regard to subjective and objective pain measures, complications and bleeding. Although the stone free rates, complication rates and mean drop in hemacrit were comparable between the 2 groups, visual analog pain scores were consistently lower at 6 hours and 1, 2 and 14 days post-operatively in the 10F group, although only the difference in the 6 hour scores reached statistical significance. Post-operative narcotic requirements were also correspondingly less in the 10F group, but not statistically significantly so.
  Based on this study and others, it would seem that the use of a smaller caliber nephrostomy tube results in less early post-operative pain without compromising safety or the ability to return to the operating room for second look flexible nephroscopy. Liasikos and associates (1) additionally noted that the use of a tail stent in conjunction with a small nephrostomy tube compared with a standard 24F re-entry tube reduced urine drainage from the tract as well as produced less pain; however, urine drainage was not assessed in the current study. Furthermore, avoiding the stent obviates the need for office stent removal and the associated cost and discomfort associated with it. Likewise, a small bore nephrostomy tube has an advantage over a “tubeless” PCNL in that the nephrostomy tract is maintained in the event residual stones are identified on post-operative imaging studies and second-look flexible nephroscopy is needed. Indeed, small-caliber nephrostomy tubes provide the ideal compromise for management of uncomplicated PCNL in that they maintain the nephrostomy tract, maximize comfort and obviate the need for an internal stent.

Reference
1. Liatsikos EN, Hom D, Dinlenc CZ, Kapoor R, Alexianu M, Yohannes P et al.: Tail stent versus re-entry tube: A randomized comparison after percutaneous stone extraction. Urology. 2002; 59: 15-9.

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