The relationship between the force applied and perceived by the surgeon during ureteral access sheath placement: ex-vivo experimental model.

PURPOSE: To define a peak force of insertion (PFOI) threshold for ureteral damage during ureteral access sheath (UAS) placement on an experimental ureteral orifice model. METHODS: A specially designed water tank using 2 laparoscopic 5 mm ports and 2 different size (10 Fr and 8 Fr) sealing cap adaptors (SCA) as ureteral orifices was used to perform the test. A 10-12 Fr UAS was fixed to a load cell and the force of insertion (FOI) was continuously recorded with a digital force gauge.13 experts in the field of endourology who participated performed 3 UAS insertions. The FOI was recorded initially with 10 Fr followed by 8 Fr SCA. On the final insertion, the orifice was obstructed, leaving a 5 cm length to insert the UAS. The experts were asked to "Stop at the point they anticipate ureteral damage, and they would not proceed in real life". RESULTS: Using 10 Fr SCA the PFOI was 2.12 ± 0.58 Newton (N) (range:1.48-3.48) while 8 Fr SCA showed a PFOI 5.76 ± 0.96 N (range:4.05-7.35). Six of the experts, said they would stop proceeding when they reached above 5.1 N. Three experts had PFOI < 5.1 N and the other 4 stated they would go with PFOIs of 5.88, 6.16, 6.69 and 7.35 N when using SCA of 8 Fr.The highest load they would stop proceeding had a PFOI of 6.09 ± 1.87 N (range: 2.53-10.74). CONCLUSION: The PFOI threshold for ureteral damage inserting UAS of the experts is variable. Although FOI is a subjective perception, experience suggests that ureteral injury may occur at an average of 6.05 N perceived by surgeons' tactile feedback. In-vivo measurement of UAS PFOI may confirm a threshold.

Experts' recommendations in laser use for the treatment of urolithiasis: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training-Research in Urological Surgery and Technology (T.R.U.S.T.)-Group.

PURPOSE: To identify laser lithotripsy settings used by experts for specific clinical scenarios and to identify preventive measures to reduce complications. METHODS: After literature research to identify relevant questions, a survey was conducted and sent to laser experts. Participants were asked for preferred laser settings during specific clinical lithotripsy scenarios. Different settings were compared for the reported laser types, and common settings and preventive measures were identified. RESULTS: Twenty-six laser experts fully returned the survey. Holmium-yttrium-aluminum-garnet (Ho:YAG) was the primary laser used (88%), followed by thulium fiber laser (TFL) (42%) and pulsed thulium-yttrium-aluminum-garnet (Tm:YAG) (23%). For most scenarios, we could not identify relevant differences among laser settings. However, the laser power was significantly different for middle-ureteral (p = 0.027), pelvic (p = 0.047), and lower pole stone (p = 0.018) lithotripsy. Fragmentation or a combined fragmentation with dusting was more common for Ho:YAG and pulsed Tm:YAG lasers, whereas dusting or a combination of dusting and fragmentation was more common for TFL lasers. Experts prefer long pulse modes for Ho:YAG lasers to short pulse modes for TFL lasers. Thermal injury due to temperature development during lithotripsy is seriously considered by experts, with preventive measures applied routinely. CONCLUSIONS: Laser settings do not vary significantly between commonly used lasers for lithotripsy. Lithotripsy techniques and settings mainly depend on the generated laser pulse's and generator settings' physical characteristics. Preventive measures such as maximum power limits, intermittent laser activation, and ureteral access sheaths are commonly used by experts to decrease thermal injury-caused complications.

Clot stones in transplant kidneys.

We describe two cases of stones with unusual radiological characteristics in transplanted kidneys that originated from a blood clot as the nidus for lithogenesis. Both patients presented years after renal transplant, with gross haematuria. CT of the urinary tract showed a stone with a peripheral hyperdense shell (Hounsfield unit, HU >500) and a radiolucent centre (HU <100). Both patients underwent percutaneous nephrolithotomy successfully.Stone analysis showed that the outer shell was calcium oxalate monohydrate and further examination of the stone in the second case confirmed an inner layer of organised clot material. Although the management of these clot stones is similar to that of other types of stones, clinicians should be aware of such a phenomenon and investigate the patients for the possibility of stone formation after haematuria, especially in allograft kidneys.

Laparoscopic Pyelolithotomy for treating urolithiasis in ectopic pelvic kidneys

ABSTRACT Introduction: The management of urolithiasis ectopic pelvic kidneys (EPK) can be challenging because of the aberrant anatomy (1-4). We demonstrate the step-by-step technique of the laparoscopic approach for treating urolithiasis in EPK. Patients and methods: Three men with EPK (2 left, 1 right) underwent laparoscopic pyelolithotomy through a transperitoneal approach. After establishing the pneumoperitoneum, the parietal peritoneum was opened at the parietal colic sulcus and the bowel displaced medially. The kidney was identified in the retroperitoneum and the renal pelvis exposed after removal of the perirenal adipose tissue. The renal pelvis was opened, and the stones were identified and retrieved with forceps in 2 cases and with a flexible nephroscope in 1 case. The renal pelvis was closed with a 3/0 running barbed suture. A DJ stent was placed in all patients. Results: For the first time, a laparoscopic technique for treating stones in the ectopic kidney is demonstrated in detail. Mean patient age was 52.6 years (44-58). The mean stone size was 22.3 mm (20-24 mm). Stones were in the renal pelvis in 2 cases and in the inferior calyx in 1 case. Mean operative time was 146 minutes (135-155 min). Mean estimated blood loss was 116 ml (60-140 ml). No complications were observed. The mean hospital stay was 3 days. The DJ stents were removed after 3 weeks. All patients were stone free at the postoperative CT scan with a mean follow-up of 3.3 months (1-6 months). Conclusions: Laparoscopic pyelolithotomy can be an effective and reproducible minimally invasive technique for treating urolithiasis in EPK.

Evaluation of the Spies TM modalities image quality

Introduction The Spies™ system (Karl-Storz®) was introduced into digital ureteroscopy to improve endoscopic vision. To date, there is no data to either indicate which of the Spies modalities is better for improving diagnosis and treatment procedures, nor to compare the modalities in terms of image quality. The aim of this study was to evaluate and compare the image quality of five Spies™ modalities (SM) to the standard white light in an in-vitro model. Materials and Methods Two standardized grids and 3 stones of different composition were recorded in white light and the 5SM (Clara, Chroma, Clara+Chroma), Spectra A and B) using 4 standardized aqueous scenarios. Twelve templates were done in order to simultaneously compare the same objective in the different modalities. Six urologists, five medical students, five urology residents, and five persons not involved with urology evaluated each video on a scale of 1 (very bad) to 5 (very good). Results Comparing white light to SM, subjects scored better the quality of Clara and Clara+Chroma than white light (p=0.0139 and p<0.05) and scored worse Spectra A and B (p=0.0005 and p=0.0023)). When comparing Clara to the other SM, it was ranked equivalent to Clara+Chroma (p=0.67) and obtained a higher rank than Chroma, Spectra A and B (p<0.05, p=0.0001 and p=0.0001). In the multivariate analysis mean scores were higher among urologists. Conclusion In all analyzed scenarios, the subjects ranked Clara and Clara+Chroma as the modalities with better image quality compared to white light.

A prospective multicenter European study on flexible ureterorenoscopy for the management of renal stone

ABSTRACT Purpose The aim of this study was to describe the outcomes and the complications of retrograde intrarenal surgery (RIRS) for renal stones in a multi-institutional working group. Materials and Methods From 2012 to 2014, we conducted a prospective study including all RIRS performed for kidney stones in 4 European centers. Demographic information, disease characteristics, and perioperative and postoperative data were gathered. Patients and stone data, procedure characteristics, results and safety outcomes were analyzed and compared by descriptive statistics. Complications were reported using the standardized Clavien system. Results Three hundred and fifty-six patients underwent 377 RIRS with holmium laser lithotripsy for renal stones. The RIRS was completed in all patients with a mean operative time of 63.5 min. The stone-free status was confirmed endoscopically and through fluoroscopic imaging after the first procedure in 73.6%. The second procedure was performed in twenty patients (5.6%) achieving an overall stone free rate of 78.9%. The overall complication rate was 15.1%. Intra-operative and post-operative complications were seen in 24 (6.7%) and 30 (8.4%) cases, respectively. Conclusions RIRS is a minimally invasive procedure with good results in terms of stone-free and complications rate.