Ureteral Wall Injury with Ureteral Access Sheaths: A Randomized Prospective Trial

Peak Force of Insertion During Ureteral Access Sheath Placement In An Ex-Vivo Experimental Model With Different Commercially Available Access Sheaths

OBJECTIVES

To measure the force necessary to win the resistance during insertion of ureteral access sheaths (UAS) in an experimental homemade model and to compare the peak force of insertion (PFOI) of different commercially available UASs.

METHODS

Three investigators (2 novice and 1 expert) inserted the UASs into 2 different adapters with diameters of 10 Fr and 8 Fr. The force of insertion was continuously measured with a digital force gauge connected to the UAS during each insertion. Four different brands of UAS with different diameters, totally 11 different UASs were used for the experiment. The PFOI of each UAS was compared among each other and adapter diameters.

RESULTS

The mean PFOI in adapters 1 and 2 were 1.85 N and 5.32 N, respectively. All of the mean PFOIs were significantly lower in adapter 1 compared to adapter 2, regardless of the novice vs expert surgeons and the UASs. (p<0.001) In adapter 1, the mean PFOI was lowest with the UAS-1 and highest with the UAS-8. In adapter 2, the mean PFOI was lowest with the UAS-3 and highest with the UAS-9. For adapters 1 and 2, no statistical difference was found when comparing an expert and the two novice surgeons.

CONCLUSION

The PFOI during UAS placement is not solely correlated with UAS thickness and adapter diameters. Other factors such as hydrophilic coating, UAS flexibility, inner dilator properties, UAS smoothness and the actual measured external diameter of UASs should be taken into consideration. The clinical relevance and ureteral injury risk of the UAS PFOI needs to be studied.

Verification of surgical factors affecting the efficiency of stone extraction with one-surgeon basketing technique using a f-URSL simulation model

PURPOSE

Stone extraction is an important treatment option when performing flexible ureteroscopic lithotripsy (f-URSL) for upper urinary stones. We used a f-URSL simulator model to investigate surgical factors affecting the efficacy of stone extraction with the one-surgeon basketing technique.

MATERIALS AND METHODS

This simulator-based study involved eight urologists and eight residents. These participants each performed two tasks, with Flexor (Cook Medical) and Navigator (Boston Scientific) ureteral access sheaths, with and without the M-arm (MC Medical) single-use basket holder, and with models representing both left and right kidneys. The two tasks were to touch each renal calix with the ureteroscope, and to extract stones. As outcomes, we recorded the number of times that the ureteroscope became stuck during insertion, the number of times a stone was dropped during removal, the number of times the basket forceps were opened and closed, and the time required to accomplish each task.

RESULTS

The ureteroscope became stuck significantly more often when Navigator was used compared with Flexor overall, and for both urologists and residents (all p<0.01). Stones were dropped significantly more often on the ipsilateral side (kidney on the same side as the operator's hand) than on the contralateral side overall (p=0.01), and the basket forceps were opened and closed significantly more often on the ipsilateral side than on the contralateral side both overall and by residents (all p<0.01).

CONCLUSIONS

The efficiency of stone extraction during f-URSL with the one-surgeon basketing technique was affected by differences in ureteral access sheath and the kidney side.

Surgical Force: Initial Study and Clinical Implications in the Assessment of Ureteral Access Sheath Induced Injury

Purpose: Ureteral access sheaths (UAS) pose the risk of severe ureteral injury. Our prior studies revealed forces ≤6 Newtons (N) prevent ureteral injury. Accordingly, we sought to define the force urologists and residents in training typically use when placing a UAS. Materials and Methods: Among urologists and urology residents attending two annual urological conferences in 2022, 121 individuals were recruited for the study. Participants inserted 12F, 14F, and 16F UAS into a male genitourinary model containing a concealed force sensor; they also provided demographic information. Analysis was completed using t-tests and Chi-square tests to identify group differences when passing a 16F sheath UAS. Participant traits associated with surpassing or remaining below a minimal force threshold were also explored through polychotomous logistic regression. Results: Participant force distributions were as follows: ≤4N (29%), >6N (45%), and >8N (32%). More years of practice were significantly associated with exerting >6N relative to forces between 4N and 6N; results for >8N relative to 4N and 8N were similar. Compared to high-volume ureteroscopists (those performing >20 ureteroscopies/month), physicians performing ≤20 ureteroscopies/month were significantly less likely to exert forces ≤4N (p = 0.017 and p = 0.041). Of those surpassing 6N and 8N, 15% and 18%, respectively, were high-volume ureteroscopists. Conclusions: Despite years of practice or volume of monthly ureteroscopic cases performed, most urologists failed to pass 16F access sheaths within the ideal range of 4N to 6N (74% of participants) or within a predefined safe range of 4N to 8N (61% of participants).

Summary Paper of the Updated 2023 European Association of Urology Guidelines on Urological Trauma

CONTEXT

The European Association of Urology (EAU) Guidelines Panel for Urological Trauma has produced guidelines in order to assist medical professionals in the management of urological trauma in adults for the past 20 yr. It must be emphasised that clinical guidelines present the best evidence available to the experts, but following guideline recommendations will not necessarily result in the best outcome. Guidelines can never replace clinical expertise when making treatment decisions for individual patients regarding other parameters such as experience and available facilities. Guidelines are not mandates and do not purport to be a legal standard of care.

OBJECTIVE

To present a summary of the 2023 version of the EAU guidelines on the management of urological trauma.

EVIDENCE ACQUISITION

A systematic literature search was conducted from 1966 to 2022, and articles with the highest certainty evidence were selected. It is important to note that due to its nature, genitourinary trauma literature still relies heavily on expert opinion and retrospective series.

EVIDENCE SYNTHESIS

Databases searched included Medline, EMBASE, and the Cochrane Libraries, covering a time frame between May 1, 2021 and April 29, 2022. A total of 1236 unique records were identified, retrieved, and screened for relevance.

CONCLUSIONS

The guidelines provide an evidence-based approach for the management of urological trauma.

PATIENT SUMMARY

Trauma is a serious public health problem with significant social and economic costs. Urological trauma is common; traffic accidents, falls, intrapersonal violence, and iatrogenic injuries are the main causes. Developments in technology, continuous training of medical professionals, and improved care of polytrauma patients reduce morbidity and maximise the opportunity for quick recovery.

The outcomes of flexible ureteroscopy for renal calculi of 2 cm or more with and without the use of ureteral access sheath: A retrospective study

INTRODUCTION

The rate of success of retrograde intrarenal surgery (RIRS) for treating urinary tract stones is high, and the procedure is growing in popularity. The routine use of ureteral access sheath (UAS) remains somewhat controversial. The aim of this study was to assess the efficacy and safety of employing UAS during flexible ureteroscopy for treating renal stones ≥ 2 cm.

METHODS

This retrospective study was accomplished from January 2021 to February 2023. From 495 consecutives flexible ureteroscopies, 112 patients had renal stones ≥ 2 cm (60 patients with the use of UAS and 52 patients without). The stone-free status was verified after 8 weeks of operation.

RESULTS

The average diameter of the renal stones in non-UAS or UAS treated groups was 22.5 mm and 22.6, respectively. None of the groups differed significantly in terms of stone side, stone size, stone position, or Hounsfield unite but there was significant difference (p < 0.001) among two groups as regard pre-operative stenting (cases with UAS had 23.3% pre-operative stenting).

CONCLUSIONS

It is not always necessary to use UAS in conjunction with flexible ureteroscopy and laser lithotripsy to treat renal calculi bigger than or equal two cm. Without the assistance of UAS, the surgery may be carried out successfully and safely.

Effect of bladder emptying status on the ureteral access sheath insertion resistance and following ureteral injury in RIRS: a prospective randomized controlled trial in academic hospital

PURPOSE

To evaluate the effect of bladder emptying status on the ureteral access sheath (UAS) insertion resistance and following ureteral injury.

METHODS

Eighty patients were enrolled and randomly divided into bladder emptying group and control group before UAS placement. A digital force gauge (Imada Z2-50N) was used to measure the resistance during the UAS insertion. The ureteral injury was evaluated and graded with Post-Ureteroscopic Lesion Scale (PULS) system at the end of procedure. The mean resistance, maximum resistance in different ureteral segments, and ureteral injury were compared between the two groups.

RESULTS

The mean resistance (3.12 ± 0.49 vs. 4.28 ± 0.52 N, P < 0.001), maximum resistance in the whole procedure (5.17 ± 0.72 vs. 6.39 ± 0.96 N, P < 0.001) and distal ureter (3.07 ± 0.75 vs. 6.18 ± 1.17 N, P < 0.001) in the bladder emptying group were significantly lower when compared to the control group. In subgroup analysis, the similar result was also noted in patients with BMI ≥ 25 when compared to patients with BMI < 25, while there was no significant difference between men and women, age ≥ 50 years versus age < 50 years. The incidence of PULS 1-2 ureteral injury in the bladder emptying group was lower than the control group (35% vs. 55%, P = 0.045). The ureteral injury in distal ureteral was less frequently noted in bladder emptying group than the control group (22.5% vs. 55%, P = 0.006); however, there was no significant difference in middle and upper ureter (P > 0.05).

CONCLUSION

Emptying the bladder before UAS insertion can effectively reduce the UAS insertion resistance and the risk of distal ureteral injury in RIRS.

Comparison of commonly utilized ureteral access sheaths: A prospective randomized trial

OBJECTIVE

We aimed to evaluate and compare the functional characteristics, safety profile and effectiveness of two commonly used ureteral access sheaths (UAS) during flexible ureteroscopy.

METHODS

After institutional review board approval, patients with proximal ureteral or kidney stones requiring flexible ureteroscopy and UAS were prospectively randomized to group I or group II according to the type of access sheath used. Primary outcome was incidence of intraoperative complications.

RESULTS

Eighty-eight patients were enrolled in the study, 44 patients in each group. Sheath size 12/14 FR was used in both cohorts. Median (IQR) stone size was 10 mm (7-13.5) and 10.5 mm (7.37-14) in group I and II respectively (p = 0.915). Nineteen and twenty patients, in group I and II respectively, were pre-stented. Subjective resistance with insertion of the UAS was observed in 9 and 11 patients in group I and II respectively (p = 0.61) while failed insertion was encountered in one patient in group I. Traxer grade 1 ureteral injury was noted in 5 and 6 patients in group I and II respectively while grade 3 injury was seen in 1 patient for both cohorts (p = 0.338). There was less resistance for UAS placement in pre-stented patients (p = 0.0202) but without significant difference in ureteric injury incidence (p = 0.175). Emergency department visits were encountered in 7 (group I) and 5 patients (group II) (p = 0.534).

CONCLUSIONS

The studied UASs were comparable regarding safety and efficacy in the current study. Pre-stented and dilated ureters had less resistance to insertion although this was not reflected on incidence of ureteric injury.

Evaluation of ureteral injuries caused by ureteral access sheath insertion during ureteroscopic lithotripsy

OBJECTIVE

To evaluate ureteral injuries caused by insertion of a 13-Fr ureteral access sheath and identify factors (other than pre-stenting) that are predictive of ureteral injury.

METHODS

We enrolled 201 patients who underwent ureteroscopic lithotripsy (URSL). We excluded 80 patients who underwent ureteral stent insertion before URSL, 10 patients who did not use a ureteral access sheath, and 2 patients in whom a ureteral access sheath could not be inserted. In total, 109 patients were analyzed; all underwent insertion of a 13-Fr ureteral access sheath. We investigated ureteral injuries using the Traxer ureteral injury scale.

RESULTS

There were 21 (19.3%) cases of ureteral access sheath-related ureteral injury, including 11 (10.1%) grade 2 cases and 10 (9.2%) grade 3 cases. The ureteral injury location was the proximal ureter in 20 cases (18.3%), middle ureter in one case (0.9%), and distal ureter in zero cases. Multiple logistic regression analysis showed that male sex and smaller stone diameter were significant predictive factors for ureteral injury (p = 0.037, odds ratio [OR]: 5.19, 95% confidence interval [CI]: 1.11-24.3 and p = 0.02, OR: 0.83, 95% CI: 0.71-0.97, respectively). Postoperative ureteral stricture did not occur in any cases.

CONCLUSIONS

The rate of ureteral injury caused by a 13-Fr ureteral access sheath was considerable, and most ureteral injuries occurred in the proximal ureter. Male sex and smaller stone diameter were significant predictive factors for ureteral injury. The proximal ureter should be confirmed when using a 13-Fr ureteral access sheath, particularly in male patients and patients with small stones.

Single-Session Impact of High-Power Laser with Moses Technology for Lower Pole Stones in Retrograde Intrarenal Surgery: Retrospective Study

Background: This study aimed to evaluate the efficacy of a high-power holmium laser with Moses technology (MT) for the treatment of lower pole stones during retrograde intrarenal surgery (RIRS). Methods: Herein, 305 patients with lower pole stones who underwent RIRS using a high-power holmium laser with MT were retrospectively classified into the stone-free (SF) and non-SF groups. We measured the stone burden, stone volume, stone hardness, pre- or post-operative stent placement, infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height in terms of pelvicalyceal anatomy using retrograde pyelograms and evaluated the predictive factors of postoperative SF. Results: A total of 173 (56.7%) and 229 (75.1%) patients achieved a SF status on postoperative day one and at one month, respectively. Operation time in the SF group was shorter than that in the non-SF group (51.0 vs. 74.5 min). There were no significant differences in postoperative complications between the SF and non-SF groups. Significantly predictive risk factors in postoperative SF included total stone volume (odds ratio (OR), 1.056; 95% CI, 1.015-1.099; p = 0.007), IPA (OR, 0.970; 95% CI, 0.956-0.993; p = 0.009), and IW (OR, 0.295; 95% CI, 0.121-0.718; p = 0.007). The cut-off values of stone volume, IPA, and IW were 515.2 mm³, 46.8°, and 7.75 mm, respectively. Conclusions: A high-power holmium laser with MT in lower pole stones is a valuable option for positive outcomes and patient's safety. Larger stone volume, acute IPA, and narrow IW were negative predictors related to postoperative SF status.

The use of ureteral access sheath during mini-percutaneous nephrolithotomy with high-power holmium YAG laser

PURPOSE

To present our preliminary results and describe a technical modification of mini-PCNL (12Fr) with the insertion of a ureteral access sheath (UAS) to facilitate the procedure.

METHODS

A prospective study for the time period of January 2020 to January 2021 was conducted including patients with renal stones sized ≤ 25 mm in whom prone mini-PCNL (tract size 12Fr) together with the retrograde insertion of UAS was performed. All patients had been prestented at least 1 week prior to the planned surgery. A single-step tract dilation to 12Fr diameter was performed through a nonpapillary medial puncture. The lithotripsy was achieved using high-power holmium yttrium aluminum garnet laser (Ho:YAG) with the 60 W power setting (40 Hz and 1.5 J). The follow-up investigations were planned at 1-month after the surgery.

RESULTS

In total, 32 patients with the median age and stone size of 56.5 (IQR = 53-62) years and 20.8 (IQR = 19.3-22.7) mm were included. The median operative and cumulative fluoroscopy time were 34.0 (IQR = 29.9-37.5) and 1.9 (1.8-2.1) min, respectively. The stone-free rate (SFR) at 1-month follow-up was 93.8% (30/32). Only one patient developed a fever and required prolonged antibiotic administration. None of the patients experienced clinically significant bleeding.

CONCLUSION

Our preliminary results showed that the use of UASs during mini-PCNL procedures is feasible and provides directed evacuation of the stone fragments reaching 93.8% SFR at a 1-month follow-up. Future well-designed studies are necessary to prove our findings.

The Impact of Ureteral Access Sheath Size on Perioperative Parameters and Postoperative Ureteral Stricture in Retrograde Intrarenal Surgery

OBJECTIVE

To investigate the effect of the diameter of UAS used during RIRS on operative parameters, perioperative ureteral injury, and ureteral stricture development.

MATERIAL AND METHOD

The study was designed as a prospective randomized controlled trial and included 320 patients who underwent RIRS. The patients were divided into two groups according to UAS diameter (9.5/11.5 Fr (Group 1) and 12/14 Fr (Group 2)) were used during the operation. At the end of the operation, ureteral injury was checked visually using semi-rigid ureterorenoscopy and classified according to the ureter injury scale. In the postoperative first year, the control CT urography images used to newly developed ureteral dilation.

RESULTS

There was no statistical difference between the two groups in terms of patient and stone characteristics, operative time, postoperative stone-free rate, and postoperative infection development parameters. In Group 1, 30 (18.8%) of the patients had low-grade and 8 (5%) of the patients had high-grade ureteral injury while in Group 2, 44 (27.5%) had low-grade and 19 (11.9%) had high-grade ureteral injury (p=0.013). In the postoperative period, ureteral stricture was found in 5 (1.6%) patients, of whom 4 (2.5%) were in Group 2 and 1 (0.6%) (p=0.371).

CONCLUSION

The results of our study showed that the use of a 12/14 Fr UAS in patients who are not previously stented, increases the risk of high grade ureteral injuries, however, despite this increase there is no difference in ureteral stricture formation.

Failure of ureteral access sheath insertion in primary flexible ureteroscopy for renal stones: is there any relation with inflammation?

PURPOSE

To investigate the relationship between failure to insert a ureteral access sheath (UAS) with inflammation and other clinical parameters in patients treated with flexible ureteroscopy for renal stones.

METHODS

This study included patients who underwent flexible ureteroscopy for the treatment of renal stones in our centre between 2015 and 2020. Patients who underwent any surgical procedure on the ipsilateral ureter and had a history of spontaneous stone passage were excluded. Patients were divided into two groups based on UAS insertion success (group 1) or failure (group 2). Both groups were compared with a view to clinical characteristics, preoperative neutrophil, lymphocyte, monocyte and platelet counts and ratios of these counts, all being considered inflammatory markers. A multivariate logistic regression analysis was performed to determine the independent variables affecting UAS insertion success.

RESULTS

There were 113 (59.1%) patients in group 1, while group 2 consisted of 78 (40.9%) patients. The rates of male gender, coronary artery disease and preoperative ipsilateral hydronephrosis were significantly higher in group 2, while platelet counts and platelet-lymphocyte ratios were significantly lower. Our analysis revealed four independent predictors for UAS insertion failure: female gender (odds ratio [OR]=2.1) increased the rate of UAS insertion success, while hydronephrosis (OR=1.6), low platelet counts and PLR increased the rate of UAS insertion failure (OR=0.99, OR=0.98, respectively).

CONCLUSION

Our results suggest that male gender and ipsilateral hydronephrosis are associated with increased UAS insertion failure. Although we found a relationship between relatively low platelet levels and UAS insertion failure, we think that further studies are needed to investigate this matter.

The Impact of One Week of Pre-stenting on Porcine Ureteral Luminal Circumference

OBJECTIVES

Larger ureteral access sheaths (UAS) have the potential to improve ureteroscopic stone removal outcomes, but are often avoided by surgeons due to concerns of ureteral injury. Using our novel UAS force sensor and previously defined force thresholds for ureteral injury, we sought to evaluate the impact of one week of stenting on the maximum safe dilation of ureteral luminal circumference.

METHODS

Twelve juvenile female Yorkshire pigs (24 ureters) were evaluated. The inner (i.e. luminal) circumference of each ureter was determined using Cook urethral dilators ranging from 8-24Fr in 2Fr increments, 37cm in length. Each dilator was sequentially passed while applying the UAS force sensor to measure insertion force before and after one week of stent placement. Each ureter was randomized to receive either a 4.7Fr or 7.0Fr stent (20cm). Maximum ureteral luminal circumference was defined as successful passage of the dilator to the ureteropelvic junction with <6 newtons (N) of force (the force threshold previously defined by porcine and clinical studies to avoid ureteral damage). Following passage of the largest dilator at 6N, flexible ureteroscopy was performed and a post-ureteroscopic lesion score (PULS) was recorded.

RESULTS

After one week of stent placement, the median ureteral luminal circumference increased to 15Fr representing a mean increase of 3.8Fr + 2.8 (p<0.001). Twenty-one (88%) of the pre-stented ureters had an increase in luminal circumference, with 12 ureters (50%) dilated to >16Fr (p=0.032), six ureters (25%) dilated to >18Fr, and in two cases a maximum size of 24Fr was recorded. The PULS grade was < 2 in all cases, indicating no high grade ureteral injuries. Laterality and stent size did not impact ureteral luminal circumference after pre-stenting (p=0.232 and p=0.337, respectively).

CONCLUSIONS

One week of ureteral stenting resulted in nearly a 4Fr increase in the luminal circumference of porcine ureters.

Does ureteral access sheath have an impact on ureteral injury?

Objective:

To present a well-organized review about ureteral access sheath impact on ureteral injury.

Materials and Methods:

Systemic search on literature was done. Total of 3766 studies observed by two urologists and results were unified. A Prisma diagram was used for eliminating irrelevant studies and at the end of elimination process 28 studies were found eligible for this review.

Results:

Not only clinical studies but also comparative experimental animal studies show that there is no significant data to claim that ureteral access sheath insertion causes more ureteral injury. Pre-stented patients were found to be at lower risk for ureteral injury. Risk of progression to ureteral injury seems to be low even if ureteral injury occurs with insertion of ureteral access sheath.

Conclusion:

Summary of studies’ results indicate that use of ureteral access sheath doesn’t increase ureteral injury. This review may help understanding safety profile of ureteral access sheath on evidence-based level. There is not enough data to make a statement that ureteral access sheath prevents ureteral injury.

The Life and Death of Percutaneous Stone Removal: "Looking Back-Looking Forward"

Although percutaneous nephrolithotomy (PCNL) is less morbid than open surgery, it still carries risks of significant complications as well as injury to the renal parenchyma. Flexible ureteroscopic stone removal, although causes no appreciable damage to the renal parenchyma, has limitations, most notably, a lower stone-free rate than PCNL. Advances in our knowledge regarding ureteral physiology combined with technical developments applied to ureteral access sheath deployment and size may well propel retrograde intrarenal surgery to the forefront of kidney stone removal, regardless of stone size or location.

Evaluating predictive factor of Systemic Inflammatory Response Syndrome and Postoperative Pain in Patients Without Ureteral Stent Placement After Ureteral Access Sheath Use in Flexible Ureteroscopy for Stone Management

BACKGROUND AND OBJECTIVE

This retrospective cohort study aimed to evaluate the safety of stentless flexible ureteroscopy (fURS) using a ureteral access sheath (UAS) for stone management.

PATIENTS AND METHODS

A total of 270 ureteral stentless postoperative patients were analyzed. Stentless indication was characterized by having no ureteral wall or mucosa injury with only slight erosion, < 1-hour operative time, and no endoscopic stone fragments with or without stone dust. Postoperative complications and pain were analyzed for safety measurements. In addition, preoperative and intraoperative risk factors associated with the incidence of systemic inflammatory response syndrome (SIRS) and postoperative pain were evaluated.

RESULTS

The most common UAS sizes were 10/12 Fr (69.6%) and 9.5/11.5 Fr (28.1%). The rate of patients who were stone-free was 95.9%. The median operation time was 34 min. Only three grade 1 ureteral injuries occurred intraoperatively. Postoperative SIRS occurred in 8.8% of patients, and postoperative use of analgesics was 35.9%. Only four patients were required to undergo eventual ureteral stenting. Less than 10/12-Fr UAS was the only factor positively associated with preventing postoperative SIRS (odds ratio [OR], 4.733; 95% confidence interval [CI], 1.085-20.644). Older age and preoperative ureteral stenting were positively associated with preventing postoperative pain (OR, 0.970; 95% CI, 0.951-0.990 and OR, 0.427; 95% CI, 0.232-0.786; respectively).

CONCLUSION

Stentless fURS with UAS in stone management was feasible for selected patients. UAS size of < 10/12 Fr, older age, and preoperative stenting are possible keystones to achieving stentless fURS with UAS postoperatively.

Impact of ureteral access sheath on renal stone treatment: prospective comparative non-randomised outcomes over a 7-year period

PURPOSE

To compare the outcomes (stone free rate and complications) of renal stone treatment with and without the use of ureteral access sheath (UAS). The worldwide use of UAS has risen over the last decade; however, questions still remain on the safety and outcomes with its use. We wanted to look at the role of UAS for treatment of consecutive renal stones over a 7-year period.

METHODS

The outcomes of flexible ureteroscopy and stone treatment (FURS) for renal stones with and without the use of UAS was prospectively compared from March 2012 to July 2018. Patients were divided into two groups: group-1 where UAS was used for stone treatment and group-2 where a UAS was not used. Data were collected prospectively on consecutive patients for demographics, stone size, location and number, pre and post-operative stent usage, operative time duration, stone free rate (SFR), length of stay and complications.

RESULTS

During the study period, 338 patients underwent FURS for renal stones, of which a UAS was used for 203 (60%) patients. The mean age of patients was 56 years (range 2-89 years) with a male:female ratio of 204:134. The mean cumulative stone size and the mean number of stones was 16.5 ± 10.8 mm and 11.37 ± 8.08 mm (P < 0.001), and 2.17 ± 1.99 and 1.66 ± 1.50 (P = 0.009) for groups 1 and 2 respectively. The pre and post-operative stent insertion rates were similar in the two groups. The procedural time was longer in group-1 (54.8 ± 25.8 min) compared to group-2 (41.3 ± 22.2 min) (P < 0.001). The SFR for group-1 (88%) was slightly lower than group-2 (94%) although this was not statistically significant (P = 0.07). There were no intra-operative complications in either of the groups. Post-operative complications were seen in eight patients in group-1 (7 Clavien I/II and 1 Clavien IVa) and two patients in group-2 (Clavien I) (P = 0.19).

CONCLUSION

The use of UAS for renal stones is safe with no intra-operative complications noted in our series. Good stone-free rates were obtained for large and multiple renal stones with a small risk of minor complications post-operatively.

A Prospective Study Analyzing the Association Between High-grade Ureteral Access Sheath Injuries and the Formation of Ureteral Strictures

OBJECTIVE

To assess the intermediate- and long-term effect of high-grade ureteral injuries from ureteral access sheaths.

METHODS

Patients undergoing ureteroscopy for upper tract calculi were prospectively enrolled at 2 sites from 2010 to 2015. A 12/14 French sheath was used and the ureter was inspected with a flexible ureteroscope during withdrawal of the sheath and recorded. The videos were then evaluated by 2 blinded endourologists, and any injuries were graded per the Traxer ureteral injury scale. Only high-grade injuries were included. The primary endpoint was defined as ongoing hydronephrosis without an obstructing stone on follow-up imaging indicating a ureteral stricture. Logistic regression analysis was used to assess the relationship between hydronephrosis, ureteral injury, and other patient variables.

RESULTS

Fifty-six patients were identified with high-grade ureteral injuries. Sixteen patients (28.6%) were female. Median age was 56.4 years (range 14-85). Median follow-up was 35.8 months (range 0-88). Three patients (5.5%) had hydronephrosis on follow-up imaging, only 1 of whom developed a de novo ureteral stricture. On univariate analysis, hydronephrosis was associated with a shorter stent duration (P = .11) and older age (P = .17).

CONCLUSION

Endoscopically identified high-grade ureteral lesions following ureteral access sheath placement do not lead to clinically significant sequelae on intermediate term follow-up, with a stricture rate comparable to those without visible injuries of 1.8%.