Success rate of repeat flexible ureteroscopy following previous failed access: An analysis of stent duration.

INTRODUCTION: Approximately 8% of patients that undergo therapeutic or diagnostic ureteroscopy will have the procedure aborted and ureter stented due to failed access. The primary objective of this study was to assess mean stent duration prior to repeat ureteroscopy and to calculate the associated successful access rate. METHODS: This retrospective, descriptive study evaluated all patients undergoing interval ureteroscopy following a failed procedure by endourologic surgeons at the University of Alberta from 2016-2018. Patients declining interval ureteroscopy, or those with malignant/known ureteral strictures were excluded from the study. The primary outcome measures were median time to salvage ureteroscopy and the rate of successful access of the repeat procedure. RESULTS: A total of 119 patients were identified as having a failed ureteroscopy during our study period. First-time and recurrent stone formers accounted for 64 (53.8%) and 47 (39.5%) patients, respectively. Median stent duration to second procedure was 17 days (average 20, range 10-84). Most patients had their repeat ureteroscopy at 14 days or greater (81.5%); 22 (18.5%) patients had their repeat ureteroscopy between 10 and 13 days. The success rate of a second ureteroscopy after stenting was 99.2% (118/119). CONCLUSIONS: Ureteric stenting following failed ureteroscopy leads to exceedingly high rates of successful access at interval procedure (99.2%). The standard duration of ureteric stenting employed at our institution is two weeks. Of the patients that underwent an accelerated second procedure (between 10-13 days of stenting), all had successful access at their interval procedure.

Understanding failures in getting it up: The prevalence and predictors of failed ureteral access in ureteroscopy.

INTRODUCTION: Failed access ureteroscopy (FA) describes the inability to gain adequate access to a stone to allow for treatment. The purpose of this study was to identify the prevalence of, and factors predicting FA in patients presenting with renal and ureteral stones. METHODS: We conducted a retrospective review of all ureteroscopy (URS) procedures performed for renal and ureteral stones by three endourologists over a six-month period at our center. All patients who underwent URS for the purpose of stone treatment were included. Patients were excluded if they underwent URS for non-stone diagnosis or treatment. FA was investigated in relation to demographics, medical history, stone-specific characteristics, procedure-specific characteristics, etc. Statistical analysis consisted of descriptive statistics, as well as Chi-squared and t-test analysis using SPSS statistical software version 24.0. RESULTS: A total of 188 cases were reviewed, with 8% of patients experiencing FA. Patient age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) score, emergency cases, previous stone treatment, use of computed tomography (CT) imaging, presence of hydronephrosis, and surgeon did not differ significantly between FA and successful access (SA) groups. Stone size (9.88±5.8 vs. 8.76±4.3 mm; p=0.361) was also not significantly different. However, a significant difference was noted in time from first diagnosis to URS (128 vs. 65 days, p=0.044) between the FA and SA groups, respectively. Similarly, for ureteral stones, the FA group had a significantly greater proportion of stones located in the proximal ureter (62.5% vs. 22.0%, p=0.043). CONCLUSIONS: Proximal ureteric stones were more likely to result in FA URS, and FA procedures were more likely to be preceded by extended time from first diagnosis to URS. Further investigation is necessary, and all endourology centers should track their own personal outcome data to allow for more meaningful analysis to be performed to improve patient outcomes.

Impact of LUTS on urine volume in stone formers The impact of lower urinary tract symptomatology on urine volumes in stone formers.

INTRODUCTION: We aimed to determine if there is a correlation between International Prostate Symptom scores (IPSS) and 24-hour urine collection volumes, as patients experiencing lower urinary tract symptoms (LUTS) may have impaired ability to increase fluid intake for stone prevention. METHODS: We conducted a single-centre, retrospective review was performed of stone-formers presenting from 2014-2016. Inclusion criteria were completion of an IPSS questionnaire and a 24-hour urine collection. Exclusion criteria included symptomatic stone or urinary tract infection at time of IPSS completion, inadequate 24-hour collection, or incomplete IPSS questionnaire. RESULTS: A total of 131 patients met inclusion criteria. Stratification by IPSS severity into mild (0-7), moderate (8-19), and severe (20-35) yielded groups of n=96, 28, and 7, respectively. Linear regression modelling did not reveal a correlation between IPSS score and volume (p=0.10). When compared to those with adequate urine volumes (>2 L/day, n=65), low-volume patients (<1 L/day, n=10) had a significantly higher total IPSS (11.7 vs. 6.1; p=0.036). These groups showed significant differences in their responses to questions about incomplete emptying (p=0.031), intermittency (p=0.011), and stranguria (p=0.0020), with higher scores noted in the low urine output group. CONCLUSIONS: This study is the first to examine the correlation between IPSS and 24-hour urine volume. Though our data does not show a linear relationship between urine output and IPSS, those with lower urine volumes appear to have worse self-reported voiding symptoms when compared to those with adequate volumes (>2 L/day) for stone prevention. The overall number of patients in our study is relatively small, which may account for the lack of a relationship between IPSS and 24-hour urine volumes.

The "Acute" Stone Clinic Effect: Improving Healthcare Delivery by Reorganizing Clinical Resources.

OBJECTIVE: To determine the time to specialist urologic consultation and definitive management after establishing a subspecialist administered acute stone clinic (ASC) for adults with symptomatic upper tract stones in a publically funded universal healthcare system. MATERIALS AND METHODS: We retrospectively reviewed 337 adult referrals for stone management. Three distinct 9-week periods were assessed. Group 1 patients were seen/treated by their individual urologist before inception of a general urology emergency clinic (pre-EC). Group 2 patients were seen in a pooled EC and Group 3 patients were seen in the ASC. RESULTS: A total of 337 patients (75, pre-EC; 91, EC; 171, ASC) were reviewed. Mean time to consultation for pre-EC, EC, and ASC cohorts was 29, 7, and 7 days, respectively (p < 0.05), whereas loss to follow-up decreased from 13% to 5% (p < 0.05). On average, the number of patients seen per week increased from 9 to 20. Mean time to stone surgery from date of referral was 75 days pre-EC, 43 days EC, and 25 days ASC (p < 0.05). The percentage of patients undergoing surgery was between 59% and 63% per cohort; however, the number of patients increased from 5 to 11 per week. CONCLUSIONS: By reorganizing clinical resources, a dedicated ASC was able to increase patient capacity, reduce time to urologist consultation and reduce surgical wait times.

Are We Banging Our Heads Against the Wall? The Effect of Treatment Head Wear on the Outcomes of Extracorporeal Shockwave Lithotripsy.

INTRODUCTION AND OBJECTIVE: The manufacturer for the Storz Modulith SLX-F2 lithotripter recommends treatment head exchange after 1.65 million shocks. However, there is no documentation describing longevity of the treatment head with continued usage. The objective of this study is to determine whether there is a difference in stone fragmentation effectiveness with the treatment head at the beginning versus the end of its treatment life. METHODS: We conducted a retrospective chart review of 200 patients-50 consecutive patients treated immediately preceding, and following, two separate treatment head exchanges. Primary outcome measures were stone-free rate (no stone), total stone fragmentation (any decrease in size), and fragmentation rate ≤4 mm (decrease in size with largest residual fragment ≤4 mm), based on most recent follow-up imaging post shockwave. RESULTS: There were no baseline characteristic differences between the pre-exchange and postexchange groups with respect to first time lithotripsy for the stone (85% vs. 77%), stone location, preoperative stenting (3% vs. 4%), mean stone density (912 hounsfield units [HU] vs. 840 HU), mean stone size (9.0 mm vs. 8.1 mm), stone location, and mean number of shocks delivered (3105 vs. 3089). Mean time to follow-up was 2.7 weeks in both groups, with most follow-up imaging consisting of a kidney ureter bladder X-ray (87% pre-exchange vs. 85% postexchange). Stone free (34% vs. 27%), total stone fragmentation (76% vs. 76%), fragmentation ≤4 mm (48% vs. 42%), re-treatment rates (38% vs. 51%), and complication rates (6% vs. 7%), were not statistically different between the pre and postexchange groups, respectively. CONCLUSIONS: Exchanging the Storz Modulith F2 lithotripter head at the manufacturer recommended 1.65 million shocks does not affect the stone-free or fragmentation rate. If the manufacturer's recommendation for treatment head longevity is based on clinical outcomes, then there is likely room to extend this number without affecting treatment efficacy.

Ureteroscopy and holmium:YAG laser lithotripsy: an emerging definitive management strategy for symptomatic ureteral calculi in pregnancy.

OBJECTIVES: To review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy. METHODS: A retrospective analysis was conducted at two tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and two encrusted ureteral stents were treated. The mean gestational age at presentation was 22 weeks. The mean stone size was 8.1 mm. The stones were located in the proximal ureter/ureteropelvic junction (n = 3), midureter (n = 1), and distal ureter (n = 6). RESULTS: Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetric or urologic complications were encountered. CONCLUSIONS: Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy, providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.

Predicting urinary stone composition using X-ray coherent scatter: a novel technique with potential clinical applications.

PURPOSE: Coherent scatter properties depend on the molecular structure of the scattering medium and measured scatter patterns are often characteristic of a chemical species. We explored the usefulness of coherent scatter analysis as a basis for identifying urinary calculus composition. MATERIALS AND METHODS: A laboratory system for collecting coherent scatter signals from biological specimens was developed. This technique uses a diagnostic x-ray tube and image intensifier, and measures coherent scatter from intact renal stones. The coherent scatter signatures of 6 common stone components (calcium oxalate monohydrate, calcium phosphate, calcium phosphate dihydrate, cystine, magnesium ammonium phosphate and uric acid) were acquired from pure chemical samples and stones identified by infrared spectroscopy as having a uniform composition. In addition, a sample of calculus identified as containing only calcium oxalate dihydrate was examined. The same fragmented stone samples analyzed by infrared spectroscopy were scanned using coherent scatter. RESULTS: In each case the scatter patterns from powdered chemicals and fragmented stones showed circular symmetry and consisted of a series of broad rings of various intensities. Each pure chemical sample produced a distinct coherent scatter pattern. The signatures of the stone specimens closely agreed with those of the chemical samples. CONCLUSIONS: These initial results indicate that coherent scatter analysis using diagnostic x-rays has potential as a tool for urinary calculous composition identification. Further developments in this technique may have the potential for determining the composition of a calculus in vivo before therapy, thus, aiding in therapy planning.

Holmium: YAG laser endoureterotomy for ureterointestinal strictures.

PURPOSE: The management of ureterointestinal stricture in patients who have undergone urinary diversion can be challenging. Endourological techniques have been increasingly used in recent years for ureteral stricture. While long-term results may not be as reliable or durable as those of traditional open reconstructive surgical techniques, associated morbidity is much less. The holmium (Ho):YAG laser, which has cutting and coagulating properties, has been demonstrated to have many applications in urology. We report our experience with and long-term results of Ho:YAG laser endoureterotomy for ureterointestinal strictures. MATERIALS AND METHODS: We reviewed the charts and followup history of 23 patients in whom the Ho:YAG laser was used to treat ureterointestinal anastomotic stricture. Strictures were treated percutaneously via the antegrade approach with flexible endoscopes and the holmium laser. A reversed 12/6Fr endopyelotomy stent was left indwelling for 6 weeks postoperatively. Success was defined as symptomatic improvement and radiographic resolution of obstruction. RESULTS: Between 1993 and 2000, 23 patients with a mean age of 61 years underwent endo-ureterotomy using the Ho:YAG laser for 24 ureterointestinal stricture. An overall success rate of 71% (17 of 24 cases) was achieved at a mean followup of 22 months. The success rate of holmium laser endoureterotomy for ureterointestinal stricture at 1, 2 and 3 years was 85%, 72% and 56%, respectively. Seven patients had recurrent strictures of which 4 developed 16 months or more postoperatively. No complications were noted. CONCLUSIONS: Ho:YAG laser endoureterotomy for ureterointestinal stricture disease is a minimally invasive endourological procedure that may provide more durable results than other modalities used for endoureterotomy. The Ho:YAG laser with its ability to cut tissue precisely and provide hemostasis combined with its versatility and compatibility with flexible endoscopes is an ideal instrument for safely performing endoureterotomy.

Holmium:YAG laser lithotripsy for upper urinary tract calculi in 598 patients.

PURPOSE: We assessed the effectiveness and safety of holmium:YAG laser lithotripsy for managing upper urinary tract calculi in a prospective cohort of 598 patients. MATERIALS AND METHODS: Ureteroscopic holmium:YAG laser lithotripsy was performed in 598 patients between 1993 and 1999. Calculi were located in the distal ureter in 39.6% of cases, mid ureter in 18.6%, proximal ureter in 32.4% and kidney in 9.4%. Patients were treated on an outpatient basis with various flexible and semirigid endoscopes. Of the cases 59% were referred as previous treatment failures. Patients were assessed 6 to 12 weeks postoperatively with repeat plain x-ray and ultrasound or excretory urography for late obstructive complications. RESULTS: The overall stone-free rate was 97%. As stratified by location, the stone-free rate was 98% in the distal ureter, 100% in the mid ureter, 97% in the proximal ureter and 84% in the kidney. Fragmentation was incomplete in 6% of cases and secondary intervention was required in 6%. The overall complication rate was 4%. New onset ureteral stricture developed postoperatively in 0.35% of patients. CONCLUSIONS: Holmium:YAG laser lithotripsy is a highly effective and safe treatment modality for managing ureteral and a proportion of intrarenal calculi on an outpatient basis. The effectiveness and versatility of the holmium laser combined with small rigid or flexible endoscopes make it our modality of choice for ureteroscopic lithotripsy.