647 An Audit of Spontaneous Stone Passage in Patients on the Waiting List for Ureteroscopy

Aim To determine the waiting list time from emergency stenting to elective management of ureteric stones. To identify the number of emergency patients who spontaneously pass their stone, whilst awaiting elective Ureteroscopy. To assess the benefit of pre-operative CT in reducing negative elective ureteroscopy rates. Method Retrospective study of all patients who underwent emergency stenting for renal colic and were placed on the waiting list for ureteroscopy. Patients were identified from the waiting list register using the relevant procedure codes and data was taken from the electronic patient record system. Results We identified 51 patients who were added to the waiting list in 2022 following emergency stenting for renal colic. Median waiting list time from emergency stent to URS was 21 weeks, with 41% affected by cancellations. 21 patients had pre-operative CT scans, of which 7 had passed their stones. 2 patients were found to have no stones at the time of ureteroscopy. 14 patients had encrusted stents at the time of elective surgery. Conclusions Our negative ureteroscopy rate was surprisingly low, however it may still be beneficial to repeat imaging in patients waiting longer than 6 months for surgery or where symptoms have changed. Of those patients who had undergone pre-operative imaging, a third had passed their stones. Thus, avoiding the risks of a further surgery and anaesthetic.