1110-5712 Vol. 20, No. 3, 2014 Egyptian Journal of Urology 121-125 RETROGRADE URETEROSCOPIC HOLMIUM: YAG LASER LITHOTRIPSY FOR URETERAL AND RENAL STONES AHMED EL-FEEL, AHMED SAMIR, HESHAM FATHY, OMAR M ABDEL-RAZZAK Urology Department, Cairo University, Cairo, Egypt. Purpose: To evaluate retrograde ureteroscopic Holmium: YAG (Ho: YAG) laser lithotripsy using semirigid and flexible ureteroscopy in the treatment of ureteral and renal stones. Materials and Method: Forty-four patients with mean age of 47.7±15.1years were enrolled in this study. Selection criteria included ureteral and renal stones measuring 1 cm with difficult ureteral anatomy orpoor candidates for percutaneous nephrolithotomy (PCNL), or those referred with impacted stones after failed trials of extracorporeal shock wave lithotripsy (ESWL) monotherapy. Based on the preoperative radiology, 36 patients (82%) had ureteric stones and 8 patients (18%) had renal stones with a mean stone size of 1.7±0.5cm (range 1-4 cm). Results: Mean operative time was 74.2±17.4 minutes with 89% stone free rate. Early postoperative complications were seen in 7 patients (16%), all of which were grade-i complications. Analyses of data did not show any impact for Body mass index or history of ESWL on the mean operative time, stone free rate or complication rate. On the other hand, renal stones were associated with a lower stone free rate (p=0.0001) and a higher complication rate (p=<0.0001), while larger stones measuring >2cm were associated with longer operative time (p=0.03) and lower stone free rate (p=0.04). Conclusions: Retrograde ureteroscopic Ho:YAG laser lithotripsy is effective in managing ureteral and renal stones. It has an acceptable stone free rate and is safe, making it a highly efficient technique in situations where ESWL or PCNL would fail. Renal stones and those > 2cm are associated with lower stone free rate. Keywords: Ureteroscopy, Holmium: YAG Laser, Lithotripsy. INTRODUCTION Retrograde ureteroscopic laser lithotripsy has gained an increasing interest since the introduction of Holmium: YAG (Ho: YAG) laser to the urologic field.a number of studies have shown its efficacy, so that it has becomea good alternative for patients with difficult ureteral anatomy or those who are not suited for percutaneous nephrolithotomy (PCNL). 1,2 In this study, we evaluated retrograde ureteroscopic Ho: YAG laser lithotripsy used for treating ureteral and renal stones; with reference to the factors that would affect its feasibility, efficacy and safety outcome. MATERIALS AND METHODS Between April 2013 and April 2014, 44 patients (26 females and 18 males) with upper tract stones were enrolled in a cohort study to evaluate retrograde ureteroscopic laser lithotripsy. Selection criteria included patients with upper tract stones (ureteral or renal pelvicequal of more than 1 cm with difficult ureteral anatomy or poor candidates for PCNL, or those referred with impacted stones following trials of ESWL monotherapy. Exclusion criteria were staghorn renal pelvic stones. The age of patients ranged from 4 to 79years with mean 47.7±15.1years; the majority were between 50-60years with lower incidence at extremities of age. The Body mass index (BMI) ranged from 16.6 to 56.2kg/m 2 with a mean of 28.9±6.6kg/m 2 (6 patients were normal with BMI < 25kg/m 2, 28 patients were overweight with BMI 25 30kg/m 2 and 10 patients were obese with BMI > 30kg/m 2 ). Eighteen patients (41%) were referred to this study with previous failed trials of ESWL monotherapy, which were associated with stone impaction and ureteral obstruction. Radiological assessment of the stones was performed using non-contract spiral CT of abdomen and pelvis (NCCT) to accurately assess stone size and number. Based on the preoperative NCCT assessment, 36 patients (82%) had ureteral stones (lower ureter in 13 patients, mid-ureter in 12 patients and upper 121
ureter in 11 patients) and 8 patients (18%) had renal stones. The stone size ranged from 1 4 cm with a mean of 1.7±0.5cm, where 37 patients (81%) presented with stones measuring 1 2 cm and 7 patients (19%) presented with stones more than 2 cm. According to their location, 36 patients (82%) had ureteral stones with a mean size of 1.5±cm and 8 patients (18%) had renal stones with a mean stone size of 2.3±0.8cm (difference in stone size between ureteric and renal stone was statistically significant; p=0.03). Our technique of retrograde Ho: YAG laser lithotripsy starts with cystoscopy and retrograde study to assess the upper tract and place a working guide wire for the semirigid ureteroscopy (Karl-Storz 9.5 Fr.); the use offlexibleureteroscopy (Flex-X2 Karl-Storz) was donein conjunction with semirigid ureteroscopy only when needed. The Ho: YAG laser machine (Sphinx 45 watts, LISA Laser, USA) was set at an energy level between 10 and 25 watts, and the tip of the laser fibre(365 micron fibre was used with semirigid ureteroscopy and 200 micron fibre with the flexible ureteroscopy) was directly applied on the stone (contact mode) aiming at its fragmentation into very fine gravels that can be easily pass. Auxiliary instruments such as forceps, basket cone, or zero-tip dormia were used as needed. By the end of the procedure, a ureteral stent or a JJ stent was fixed if needed (based on the roughness of the procedure and the presence of significant residual stones). Postoperatively, the patients were given alpha blocker (Tamsulosin 0.4 mg) to allow passage of small residual fragments. Analgesics (Diclofenac sodium 50-150 mg/day) were given as required. A control NCCT was done to all the patients within the first 3 days to rule out any residual stones and it was repeated after 3 months to follow up success rate and survey possible late complications. A stone free state was defined as in patients who have no residual stones or small fragments less than 3 mm that passed completely within 3 months follow up. Data management and analyses were performed using Microsoft Excel program (Excel version 2010, Redmond Washington, Microsoft Computer Software). The T-student test (two-tailed) was used to compare of means of numerical values and the chi-square test was used to compare nominal values. P- value (null hypothesis) was considered significant when it was less than 0.05. RESULTS The mean operative time was 74.2±17.4minutes (range 45 to 140min.), with a mean fluoroscopy time of 4.5±1.4 minutes (range 3 to 7min.). On post-operative NCCT 35 patients (80%) were stone free after the first session of retrograde Ho: YAG laser lithotripsy, and another 4 patients (9%) required additional session to be stone free, yielding an overall stone free rate of 89% (39 patients). Five patients (11%) were left with residual stones with a mean stone size of 0.8±cm (their preoperative mean stone size of 2.6±1.0cm with 69.2% reduction in the mean stone size). The locations of these residuals were calyceal. Further management for these residual stones included ESWL in 2 patients, chemolysis (radiolucent uric acid stone) in another patient. This left 2 patients with their residualsbecause they were not amenable to ESWL or fit for PCNL. Both patients were extremely obese, the first patient had a BMI of 56.2 Kg/m 2 with a 4 cm stone and she was left with a 1.5 cm residual calyceal stone after retrograde Ho: YAG laser lithotripsy (62.5% reduction in the mean stone size) andthe other patient had a BMI of 50 Kg/m 2 with a 3 cm renal stone and she was left with a 1 cm residual calyceal stone (66.6% reduction in the mean stone size). Postoperative complications were reported in 7 patients (16%) during the early postoperative period (fever in 4 patients and gross hematuria in 3 patients), all of which were self-limited and classified as grade I according to the Clavien grading system. 3 No late complication was seen in the 3 months follow-up assessment. Post-operative hospital stay ranged from 2 7days with a mean 3.5±1.3days. A JJ stent was needed in 35 patients (80%). The operative time, stone free rate and complication rate were chosen as measures for feasibility, efficacy and safety of the procedure; respectively. Each parameter was evaluated for the impact of BMI (stratified as normal, overweight and obese patients), previous history of ESWL, stone location (renal versus ureteric stones) and stone size (smaller stones measuring 1 2 cm versus larger stones >2cm). Table 1 illustrates the data analyses of BMI and its impact on the mean operative time (p=0.1), stone free rate (p=0.4) and complication rate (p=), none of which was statistically significant. Table 2 illustrates the data analyses of history of ESWL and its impact on the mean 122
operative time (p=0.6), stone free rate (p=) and complication rate (p=), and again none of these factors was statistically significant. Table 3 illustrates the data analyses of stone location; where renal stones were associated with longer operative time (but was not statistically significant; p=0.07), a lower stone free rate (p=0.0001) and a significantly higher complication rate (p=<0.0001). Table 4 illustrates the data analyses of stone size, where larger stones measuring >2cm were associated with significantly longer operative time (p=0.03) and lower stone free rate (p=0.04), but with no impact on complication rate (p=0.4). Table (1): Data analyses of Body Mass Index Normal BMI < 25 Kg/m 2 (6 patients) Overweight BMI 25-30 Kg/m 2 (28 patients) Obese BMI > 30 Kg/m 2 (10 patients) Mean operative time 67.5±9.8 min 76.2±19.3 min 72.5±15.1 min 0.2 Stone free rate 100% (6/6 patients) Complication rate 33.3% (2/6 patients) 89% (25/28 patients) 11% (3/28 patients) 80% (8/10 patients) 20% (2/10 patients) 0.4 Table (2): Data analyses of history of ESWL History of previous ESWL No history of ESWL (18 patients) (26 patients) Mean operative time 72.8±18.4 min 75.2±16.9 min 0.6 Stone free rate 94% (17/18 patients) Complication rate 22% (4/18 patients) 85% (22/26 patients) 12% (3/26 patients) Table (3): Data analyses of stone location Renal stones Ureteric stones (8 patients) (36 patients) Mean operative time 88.8±23.2 min 70.9±14.3 min 0.07 Stone free rate 50% (4/8 patients) Complication rate 63% (5/8 patients) * = statistically significant 97% (35/36 patients) 6% (2/36 patients) 0.0001* <0.0001* Table (4): Data analyses of stone size Stones > 2 cm Stones 1-2 cm (7 patients) (37 patients) Mean operative time 83.6±1 min 72.4±18.0 min 0.03* Stone free rate 57% (4/7 patients) Complication rate 29% (2/7 patients) * = statistically significant 95% (35/37 patients) 14% (5/37 patients) 0.004* 123
DISCUSSION Retrograde ureteroscopic Ho:YAG laser lithotripsy was successfully completed in 44 patients with upper ureteral stones and renal via a combination of semirigid and flexible ureteroscopy. The mean operative time was 74.2±17.4 minutes, with an 89% stone free rate, and a 16% complication rate (all of which were grade I). In the meta-analysis of Aboumarzouk et al for 9 studies, they estimated operative time of 82.5 minutes (28 to 215 minutes) with an estimated stone free rate of 93.7% (77% to 96.7%) and a 10.1% overall complications.[1] Atis et al reported a 71.9±17.9 minutes operative time with a 76% stone free rate for semirigid laser lithotripsy versus 93.41±18.56 minutes operative timewith a 86.4% stone free rate for flexible laser lithotripsy. 2 In the current study, patients body habitus as referred bytheir BMI (table 1) did have any statistical impact on the mean operative time (p=0.1), stone free rate (p=0.4) or complication rate (p=). Similarly, patients presented with impacted stones following ESWL monotherapy (table 2) had no statistical impact on the mean operative time (p=0.6), stone free rate (p=) and complication rate (p=). On the other hand, renal stones (table 3) were associated with longer operative time than ureteral stones (88.8±23.2 min. vs 70.9±14.3 min.) but was not statistically significant; p=0.07). They also had a lower stone free rate (50% versus 97% for ureteral stone; p=0.0001) and a higher rate for complications (63% versus 6% for ureteric stone; p=<0.0001). As regard stone size, larger stones > 2cm (table 4) were associated with longer operative time (83.6±1 min. vs 72.4±18.0 min. for smaller stones, p=0.03), and a lower stone free rate (57% versus 95% for smaller stones; p=0.004) but with no impact on the complication rate (29% versus 14% for smaller stones; p=). It is worth mentioning that the mean stone size for renal stones was significantly larger than the ureteral stones (2.3±0.8cm for renal stones versus 1.5±cm ureteral; p=0.03). The findings in this study could be explained by the nature of fragmentation of relatively large renal stones within a capacious renal pelvis as compared to fragmenting a small ureteral stone within the narrow lumen ureter. Fragmentation of large renal stones was associated with calculus retropulsion, resulting in longer operative time, more residual stones and higher rate of complications such as fever and hematuria Deters and Pavis reviewed 213 laser lithotripsy for ureteral and renal stones, where renal stones (112 minutes) significantly increased the mean operative time when compared to ureteral stones (70 minutes; p<0.001), and in their review, renal stones were significantly larger in size (11.3 mm vs 7.7 mm;p<0.001). 4 Also, in the study of Sofer et al for 598 patients, they reported a 98% stone free rate for distal ureteral stones, 100% for mid ureter, 97% for proximal ureter versus 84% for renal stones. 5 This was also confirmed by Cohen et al in their study for 145 patients with a mean stone size of 2.9 cm; they have reported an 87% stone free rate, which was stratified according to the site into 97% for ureteral stones, 94% for renal pelvic stones, 83% for calyceal stones and 81% for staghorn stones. 6 In the current study, 5 patients (11%) had residual stones, 3 cases of whom were cleared completely by ESWL and chemolysis, while the other 2 were left with residual stones. It is worth mentioning that these 2 cases were technically challenging, none of them could have ESWL due to their weight (BMI 50 Kg/m 2 and 56.2 Kg/m 2 ) and none of them could endure a general anaesthesia in a prone position for PCNL and they had a 66.6% and 62.5% reduction in the stone size from their preoperative imaging. In a review by Wheat et al for 9 patients with similar conditions (mean BMI 47.8 Kg/m 2 ) with mean stone size of 3.8 cm, they could render only 3 patients (33%) a complete stone free state and they reported an 83% decrease in the size of the stone from preoperative imaging after multiple sessions in the other 6 patients. 7 The current study makes no exception as regard results reported by other series; retrograde ureteroscopic Ho: YAG laser lithotripsy would serve as a good alternative when PCNL or ESWL would fail. It has a high success rate with stones less than 2 cm, but a lower stone free rate would be expected for larger stones. The technique is completely safe; none of our patients experienced any intraoperative complications; early postoperative complications were all Clavien I, and no late complication was reported at 3 months. In a review by Gealvlete for complications of 2735 retrograde semirigid ureteroscopy, they reported a 5.9% intraoperative complication rate. Early complications occurred in 10.6% of cases, and late complications of ureteral stenosis and persistent vesicoureteral reflux were present in 124
5 cases. 8 Nevertheless, retrograde ureteroscopic Ho: YAG laser lithotripsy cannot be considered a substitute for PCNL or ESWL even though it seems a suitable alternative especially with smaller calculi. CONCLUSION Retrograde ureteroscopic Ho:YAGlaser lithotripsy using semirigid and flexible ureteroscopy is a feasible and effective technique in treating ureteral and renal stones. It has an acceptable stone free rate especially for ureteral stones and it is safe, making it a highly efficient technique in situations where ESWL or PCNL would fail. REFERENCES 1. Aboumarzouk OM, Monga M, Kata SG, Traxer O and Somani BK: Flexible Ureteroscopy and Laser Lithotripsy for Stones >2 cm: A Systematic Review and Meta-Analysis. J. Endourol., 2012; 26: 1257-1263. 2. Atis G, Gurbuz C, Arikan O, Canat L, Kilic M and Caskurlu T: Ureteroscopic management with laser lithotripsy of renal pelvic stones. J. Endourol., 2012; 26: 983-87. 3. Dindo D, Demartines N and Clavien PA: Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann. Surg., 2004; 240: 205-13. 4. Deters LA and Pais VM Jr: Difference in operative time according to stone location for endoscopic management of ureteral and renal stones. J. Urol., 2013; 81: 522-26. 5. Sofer M, Watterson JD, Wollin TA, Nott L, Razvi H and Denstedt JD: Holmium: YAG laser lithotripsy for upper urinary tract calculi in 598 patients. J. Urol., 2002; 167: 31-34. 6. Cohen J, Cohen S and Grasso M: Ureteropyeloscopic treatment of large, complex intrarenal and proximal ureteral calculi. BJU Int., 2013; 111: 127-31. 7. Wheat JC, Roberts WW and Wolf JS Jr: Multisession retrograde endoscopic lithotripsy of large renal calculi in obese patients. Can. J. Urol., 2009; 16: 4915-20. 8. Geavlete P, Georgescu D, Niţă G, Mirciulescu V and Cauni V: Complications of 2735 retrograde semirigid ureteroscopy procedures: a single-center experience. J. Endourol., 2006; 20: 179-85. 125