STONE DISEASE

A prospective randomized controlled trial on ureteral stenting after ureteroscopic holmium laser lithotripsy
Cheung MC, Lee F, Leung YL, Wong BB, Tam PC
Division of Urology, Department of Surgery, The University of Hong Kong, Tung Wah Hospital, Hong Kong
J Urol. 2003; 169: 1257-60

• Purpose: A prospective randomized controlled trial was conducted to evaluate whether postoperative ureteral stenting is necessary after ureteroscopic laser lithotripsy. Materials and Methods: A total of 58 patients with unilateral ureteral stones were randomized into either stented or unstented groups. Ureteroscopic laser lithotripsy was performed using a semirigid ureteroscope (6.5 / 7Fr) and holmium laser without ureteral orifice dilation. There were no selection criteria regarding stone size, location, preoperative ureteral obstruction and hydronephrosis. Endoscopic evidence of stone impaction or mucosal edema/damage did not exclude a patient from the study. Ureteral perforation on completion retrograde pyelogram was the only intraoperative criterion for study exclusion. Postoperative pain scores and symptoms were recorded. Excretory urography was performed to document stone-free status and stricture formation. Radionuclide scan was performed selectively to exclude functional obstruction when ureteral narrowing was found on excretory urogram.
• Results: Mean stone size +/- SD was 9.7 +/- 4.0 mm. (range 4 to 27). Proximal ureteral stones accounted for 43% of all stones. Stented and unstented groups were comparable with respect to demographic data, stone parameters, preoperative obstruction and hydronephrosis. There was no significant difference in operating time, laser energy used, stone impaction and mucosal edema/damage between the 2 groups. Postoperative pain and symptoms were more severe and frequent (p < 0.05) in the stented group. However, there was no difference in the incidence of postoperative sepsis and unplanned medical visits. The stone-free and stricture formation rates showed no statistical difference between the 2 groups.
• Conclusions: Ureteral stenting is not necessary after uncomplicated ureteroscopic laser lithotripsy for ureteral stones. Ureteral stent increases the incidence of pain and urinary symptoms but does not prevent postoperative urinary sepsis and unplanned medical visits. Severity of preoperative obstruction and intraoperative ureteral trauma were not shown to be determining factors for stenting.
  
• Editorial Comment
  Historically, placement of a ureteral stent after ureteroscopy for stone removal or fragmentation has been routine practice. However, recent retrospective studies and prospective, randomized trials have suggested that placement of a ureteral stent after uncomplicated ureteroscopy may be unnecessary and is associated with greater patient discomfort. The problem lies in what constitutes “uncomplicated”. Some investigators restricted their series to distal ureteral calculi only. Others excluded patients requiring balloon dilation of the intramural ureter. Still others excluded patients in whom fragments were extracted after fragmentation, while others excluded patients in whom fragments were left behind! In all cases, it was left to the discretion of the surgeon to exclude patients in whom evidence of mucosal trauma or severe impaction were present. Thus, guidelines for selection of patients who may be safely left unstented are not clear-cut.
  The authors of the present randomized trial excluded patients intraoperatively only if the stone was unable to be accessed, a concomitant ureteral stricture was present or a ureteral perforation occurred. Degree of pre-operative obstruction, stone impaction and ureteral trauma or edema did not constitute grounds for exclusion. Furthermore, middle and proximal ureteral stones comprised 59% and 28% of stones in the unstented and stented groups, respectively. Similar to other studies, the authors found no significant difference in stone free rates, post-operative fever or urinary tract infection, or need for unplanned medical visits in the 2 groups. However, also in common with other studies, urinary symptoms were greater in the stented group compared with the unstented group. This study confirms the safety of stentless ureteroscopy after treatment of stones in all locations in the ureter, but also suggests that the appearance of the ureter after stone removal, provided a perforation has not occurred, is not a reliable indicator of ureteral obstruction post-operatively. Hopefully, with additional confirmation and further study, specific criteria for post-operative stenting can be provided. However, it should be kept in mind that in cases of questionable ureteral injury, placement of a ureteral stent will never be the wrong thing to do.

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