Reducing the rate of negative ureteroscopy: predictive factors and the role of preoperative imaging.

INTRODUCTION: The aim of this study was to investigate factors that may predict a negative ureteroscopy (URS) performed for ureteric calculi in prestented patients and to assess preoperative imaging in reducing the rate of negative URS. METHODS: Data were collected on emergency stent placement for a ureteric calculus from April 2011 to February 2016 (Group A) and October 2016 to October 2019 (Group B). Data included patient demographics, indication for a stent, stone characteristics, baseline bloods, urine culture, readmission, negative URS rate and the use of pre-URS imaging. Multivariate logistic regression was used for statistical analysis. RESULTS: Of 257 patients who underwent emergency stent insertion, 251 underwent deferred URS for a ureteric calculus and 6 avoided URS due to pre-URS imaging. Indications for stent were pain (42%), sepsis (39%) and acute kidney injury (19%). Mean stone size was 7.8mm, mean stone density was 699 Hounsfield units (HU) and the stone locations were upper (62%), mid (13%) and lower ureter (25%). The overall negative URS rate was 12%. The negative URS rate was lower in patients with pre-URS imaging compared with those with none, 6% and 14%, respectively (OR=2.33, 95% CI: 0.69-7.56, p=0.2214). Logistic regression analysis indicated stone size as the only significant predictor of a negative URS, where the greater the size of the stone the less likely URS would be negative (ß=0.75, 95% CI: 0.60-0.94 p=0.011). CONCLUSIONS: Utilising pre-URS imaging can lead to a reduction in negative URS rate. Stone size <5mm appears to be the subgroup most likely to benefit from imaging.

Laparoscopic surgical skills are significantly improved by the use of a portable laparoscopic simulator: results of a randomized controlled trial.

BACKGROUND: There is growing evidence that training on virtual reality simulators leads to improved performance in the animate and human operating room. However, they are expensive, have a limited availability, and involve complex systems. Portable simulators are significantly cheaper, more user-friendly, and are flexible systems that are more suited to a surgical trainee's busy schedule. The use of portable surgical simulators to train skills and reduce errors has never been evaluated in prospective, randomized clinical settings. The objective of this study was to determine if training on the portable Integrated Laparoscopic Simulator leads to improved performance of core laparoscopic skills. METHODS: Core laparoscopic skills were identified by five experienced laparoscopic surgeons and modeled into two exercises and three basic tasks. Twenty surgically naive medical students had baseline laparoscopic skills assessed on a fixed simulator. Participants were randomized to either 14 h training on a portable laparoscopic simulator over a 3 week period, or control with no training. At 3 weeks two expert laparoscopic surgeons blinded to the allocation of participants assessed their pre- and post-intervention performances recorded on a CD-ROM. The outcome measures included time to complete and global rating scores of clipping and dissection tasks. RESULTS: No differences were observed in baseline skills level between the two groups. The intervention group had better quality of scissors dissection (p = 0.0038) and improved clipping skills (p = 0.0051), and they took less time to accomplish the tasks (p = 0.0099) in comparison to control. CONCLUSIONS: Training on the portable Integrated Laparoscopic Simulator significantly improved core laparoscopic skills in medical students with no prior experience.