Login to Access Video or Poster Abstract: MP62-16
Sources of Funding: none

Introduction

Obesity is increasingly common and often a predisposing factor in stone formation. Clinical reviews and guidelines indicate that SWL outcomes are poor for treating stones in patients with skin-to-stone distance (SSD) of >10-14cm, and regard a large SSD as an adverse predictor for SWL success (EAU Urolithiasis Guidelines 2016). There is a paucity of literature on treating such patients with SWL, and given the higher recognised perioperative morbidity of surgery in such a population, and the potential benefits of sedo-analgesia and short length of stay with ambulatory SWL, it is germane to re-evaluate the efficacy of SWL for treating such patients using a lithotriptor with a focal length of >14cm.

Methods

Consecutive patients with a solitary radio-opaque upper ureteric calculus diagnosed on CT scan with a SSD ≥14cm were identified from a prospective database (2011-2016). Out-patient SWL was performed under sedo-analgesia (diclofenac ± alfentanil) using a Sonolith I-Sys, EDAP-TMS (focal depth 17cm). Outcome was assessed with an XRKUB at 2 weeks. Those with significant fragments (>3mm) received further treatment. Success was defined as patients being free of stones on XRKUB or as having asymptomatic clinically insignificant stone fragments (CISF) ≤3mm. Failure was defined as residual fragments >3mm (treated with ureteroscopy).

Results

182 patients met the inclusion criteria. 4 were lost to follow up. Median age was 54 years. Median stone size was 8mm (range 3-21). Overall stone-free rate (SFR) was 81% after mean 1.3 sessions. 63% were stone-free after a single session. 9% had CISF≤3mm. 11% required ureteroscopy.

Conclusions

SWL can provide efficacious treatment of upper ureteric stones in obese patients, traditionally thought to be poor candidates for such treatment due to their high SSD. The upper threshold of SSD for SWL selection should be revised, as such patients can receive the benefits of effective SWL treatment, without the need for general anaesthesia, when referred to a dedicated stone centre.

Funding

none