One of the limitations of endoscopic surgical treatment of kidney stones is the removal of the fragments or dust that remain after the procedure. Different strategies have been described to address this aspect, such as the use of blood clots. The use of this autologous material has been described to prevent the movement of fragments towards the lower pole during laser fragmentation or even as a tail clot effect to remove fragments adhered to the clot.

In poster 18, Thulium laser lithotripsy of renal calculi augmented with a novel reverse thermal hydrogel in the porcine kidney. A liquid hydrogel at room temperature transforms into a gel at body temperature. This gel is postulated to protect the urothelium while lasering, avoid fragments migration and facility fragments removal as they get stuck in it. In porcine models the found an improvement of fragments removal up to 99.3% with the use of the hydrogel. Further in vivo experiments should demonstrate its applicability and safety profile.

Although new technical advances have improved the surgical treatment of kidney stone formers, the prevalence of this disease has increased in recent decades. The lack of effective preventive measures, low adherence to treatment and the inexistence of sufficiently precise diagnostic tools to detect potential recurrent kidney stone formers make it necessary to develop new strategies to prevent at least recurrence episodes of this disease.

Etiology of most of uric acid kidney stone formers (UA-KSF) is associated to low urinary pH. A device that is accurate enough, easy to use, connected to an app for digital recording of their urinary pH, can potentially help UA-KSF address personalized treatment by increasing adherence to their treatment by empowering them with their disease.

A multicenter prospective study was conducted in 10 hospitals in Spain. Adherence, usefulness, acceptability, and satisfaction of use with an intelligent digital urinary pH meter connected by Bluetooth to an App were analyzed.

Overall satisfaction with the Lit-Control pH Meter and the myLit-Control App High were high. App usability was evaluated by the validated Computer Systems Usability Questionnaire (CSU-Q) with a mean rate of 5.4 on a 0-7 point scale. Satisfaction with the products evaluated is manifested in the high probability of recommending the App to other patients, with an overall score of 8.2 on a scale of 0 to 13.

The use of a digital urinary pH meter synchronized by Bluetooth with an App may empower the May empower all stone former patients, leading them to better adherence to treatment in the prevention of new clinical episodes.

The limits between the different surgical approaches for the treatment of kidney stones present some gray areas depending on the volume, hardness or location of the stones. Better preoperative algorithms based on clinical data are needed to decide which approach is the best for a more efficient stone removal rate. Different indicators are proposed to decide which treatment should be addressed. In poster MP9-25 the whole measurement of HU of the stone is used to solve this issue.

MP9-25 Using Hounsfield Unit (HU) – Volume Models of kidney stones to predict successful stone dusting during retrograde intra-renal surgery (RIRS) Dong Soo Kim, et al. Kyung Hee University.

The volume of all HUs in a single stone was used to predict the success of dusting during RIRS. Patients with stones bigger than 1 cm where selected for the study. 49 patients were included with a total of 55 stones. A successful dusting strategy was considered if the total dusting of the stone was achieved without basketing. The study showed that stones with smaller maximum HU volumes and larger differences in maximum and minimum HU could be considered more brittle and prone to successful dusting. So, according to these results, the HU distribution should be considered when planning RIRS in borderline cases.

Thulium fiber laser (TFL) is proposed as a competitor to the gold standard of endoscopic procedures for kidney stones. Current clinical evidence showed its safe profile and higher efficiency is suggested according to some clinical studies. One of the supposed disadvantages of this laser is its lower power peak compared to the Ho:YAG laser, which could limit its use in hard stones.

In this poster, in a group of 45 patients with ureteral and kidney stones, TFL was used with a power limitation of 8-10W in the ureter and 35-40W in the kidney. Among the parameters analyzed (location, size, volume, density and composition), it was observed that the hardness (absolute HU and HU density) and composition of the stones did not affect the time of the procedure, or the total amount of laser used. Contrary to expectations, the ability to pulverize stones regardless of their hardness or composition appears to be a TFL advantage. Further studies should confirm these results.