The Fate of Residual Fragments after Extracorporeal Shock Wave Lithotripsy

Ultrasound-guided X-ray free percutaneous nephrolithotomy for treatment of simple stones in the flank position

The purpose of this study was to examine the effectiveness and safety of percutaneous nephrolithotomy with ultrasonography-guided renal access in the flank position without the use of fluoroscopy in any stage of the procedure. Percutaneous nephrolithotomy was performed in flank position under the guidance of ultrasound (USG) without the use of fluoroscopy between December 2008 and January 2010 on 43 patients who had kidney stones bigger than 20 mm. Access to the kidney's proper calyx was achieved by dilatation through the guide wire placed after insertion of the needle through the needle director under the guidance of transrectal ultrasound probe placed on the patient's flank area. A convex USG probe was used for imaging during dilatation and lithotripsy instead of fluoroscopy. Access to the targeted calyx was achieved successfully in all patients (100%). The percentage stone free rate was 86.1% (37 patients). Residual stones were detected in six patients. Their dimensions ranged from 5 to 12 mm. The mean stone diameter was 29 (20-41) mm, duration of surgery was 87.1 ± 43.2 (55-210) min and duration of hospital stay was 3.1 (2-8) days. Blood transfusions were given to two patients; none of the patients had major intraoperative or postoperative complications. In comparison with standard percutaneous nephrolithotomy, percutaneous nephrolithotomy in flank position under ultrasonographic imaging instead of using fluoroscopy seems to be safe and effective. This procedure has to be limited to selected cases with one or maximum two big stones in the pelvis or in a single calyx in absence of complex intrarenal anatomy. Both surgical team and the patients were protected from the harmful effects of radiation. Regarding anesthesia, flank position is more comfortable for the patient than prone position.

Predictors of Clinical Significance of Residual Fragments after Extracorporeal Shockwave Lithotripsy for Renal Stones

PURPOSE

To determine the predictors of the clinical outcome of residual fragments after extracorporeal shockwave lithotripsy (SWL).

PATIENTS AND METHODS

During the last 10 years, residual fragments < or =5 mm were present in 99 male and 55 female patients (mean age 43.1 years) for >3 months after SWL for renal stones. Follow-up with history, urine examination, and non-contrast CT scanning was carried out every 6 months or when symptoms developed. Clinically insignificant residual fragments were diagnosed in patients who became stone free or had asymptomatic fragments of the same size during follow-up. A clinically significant outcome was considered to have occurred in patients requiring secondary intervention for regrowth of the fragments or medical treatment for frequent symptomatic episodes. Univariate (Kaplan-Meier) and multivariate (Cox-regression) analyses were performed to determine significant predictors of the outcome. The mean follow-up was 31 months (range 6-80 months).

RESULTS

Stone-free status, regrowth of fragments, and persistence of fragments of the same size were present in 21 (13.6%), 52 (33.8%), and 81 (52.6%) patients, respectively. A clinically significant outcome was documented in 75 patients (48.7%) as percutaneous nephrolithotomy was needed in 2, repeat SWL in 50, and medical treatment for symptomatic episodes in 23 patients. Significant independent predictors of a clinically significant outcome were fragment size > or =4 mm and history of recurrent stone disease (P < 0.001).

CONCLUSION

The term "clinically insignificant residual fragments" is not appropriate for all patients with post-SWL fragments, as 48.7% of patients had fragments that became clinically significant. Fragments of 4 to 5 mm and recurrent stone disease predicted clinical significance.

Clinical Insignificant Residual Fragments (CIRF) after Extracorporeal Lithotripsy: Implications and Treatment

The stone-free status depends on the appropriate selection of the urologic treatment according to the stone and excretory tract characteristics, and/or to the patient parameters.

Although the gold standard for the treatment is the stone-free status, the authors believe that the presence of non-infected, nonobstructive, asymptomatic residual fragments, smaller than 4–5 mm, can be treated with an adequate medical therapy in order to prevent stone growth. Further urological treatment is recommended if the clinical indications for stone removal persist.

Management of residual stones

Stone-free status is highly dependent on selection of the appropriate surgical technique, which should be tailored according to the individual stone and patient parameters. Although a stone-free state is the desired outcome of surgical intervention of urolithiasis, the authors believe that the presence of noninfection, nonobstructive, asymptomatic postprocedural residual fragments can be managed metabolically in order to prevent stone growth adequately. Further surgical intervention in the case of residual fragments is warranted if the clinical indications that prompted the original surgery persist.

Management of calyceal calculi

Management of calyceal calculi has changed dramatically during the past 20 years. Minimally invasive techniques virtually have replaced open surgical stone removal. Even large and complex calyceal calculi may be treated effectively with these minimally invasive techniques. Although open surgical stone removal is performed infrequently, a clear understanding of the subtle renal anatomy aids the urologist in more effectively treating patients with calyceal calculi and in limiting surgical complications.

Effect of medical management and residual fragments on recurrent stone formation following shock wave lithotripsy

Minimal emphasis has been placed on the clinical sequelae of residual stone fragments following shock wave lithotripsy. Moreover, there are no studies investigating the role of medical therapy on the course of stone disease in patients with residual fragments. In this retrospective, nonrandomized review, we evaluated 80 patients who had undergone shock wave lithotripsy at various institutions in Texas and were referred to our mineral metabolism clinic for metabolic evaluation and medical management of the stone disease. Of the patients 31 were determined to be stone-free following lithotripsy, while 49 had residual stone fragments. All patients were contacted an average of 43.2 months (range 9 to 79) following shock wave lithotripsy and the radiographs were reviewed. Patients were placed into 4 groups after shock wave lithotripsy: stone-free or residual fragments on or off medical therapy. In the stone-free group (19 patients), medical treatment produced a significant decrease in stone formation from a median of 0.67 to 0.0 stones per patient per year (p < 0.001). In 36 patients with residual fragments stone formation before shock wave lithotripsy was higher than in the stone-free group but there was also a significant decrease in the stone formation rate from a median of 2.47 to 0.00 stones per patient per year while on medical therapy (p < 0.001). Of the 12 stone-free patients who did not remain on medical therapy there was a slight decrease in the stone formation rate from a mean of 0.83 to 0.40 stones per patient per year, although this decrease was not significant (p = 0.07). In 13 patients with residual fragments not on medical treatment there was only a minimal decrease in the stone formation rate from a median of 1.33 to 0.77 stones per patient per year (p = 0.06). We also assessed the significance of so-called clinically insignificant residual fragments (smaller than 5 mm.) following shock wave lithotripsy in 26 of the 36 patients with residual fragments. More than half of the 26 patients with clinically insignificant fragments in the group that did not continue on medical therapy demonstrated significant stone growth during followup, suggesting that these fragments were not insignificant. Moreover, only 16% of the patients with fragments smaller than 5 mm. demonstrated an increase in fragment size while on medical therapy, again suggesting that appropriate medical treatment can decrease the risk of recurrent stone formation or growth (p < 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)