Nephron Sparing Treatment (NEST) for Small Renal Masses: A Feasibility Cohort-embedded Randomised Controlled Trial Comparing Percutaneous Cryoablation and Robot-assisted Partial Nephrectomy.

There is a paucity of high-level evidence on small renal mass (SRM) management, as previous classical randomised controlled trials (RCTs) failed to meet accrual targets. Our objective was to assess the feasibility of recruitment to a cohort-embedded RCT comparing cryoablation (CRA) to robotic partial nephrectomy (RPN). A total of 200 participants were recruited to the cohort, of whom 50 were enrolled in the RCT. In the CRA intervention arm, 84% consented (95% confidence interval [CI] 64-95%) and 76% (95% CI 55-91%) received CRA; 100% (95% CI 86-100%) of the control arm underwent RPN. The retention rate was 90% (95% CI 79-96%) at 6 mo. In the RPN group 2/25 (8%) were converted intra-operative to radical nephrectomy. Postoperative complications (Clavien-Dindo grade 1-2) occurred in 12% of the CRA group and 29% of the RPN group. The median length of hospital stay was shorter for CRA (1 vs 2 d; p = 0.019). At 6 mo, the mean change in renal function was -5.0 ml/min/1.73 m2 after CRA and -5.8 ml/min/1.73 m2 after RPN. This study demonstrates the feasibility of a cohort-embedded RCT comparing CRA and RPN. These data can be used to inform multicentre trials on SRM management. PATIENT SUMMARY: We assessed whether patients with a small kidney tumour would consent to a trial comparing two different treatments: cryoablation (passing small needles through the skin to freeze the kidney tumour) and surgery to remove part of the kidney. We found that most patients agreed and a full trial would therefore be feasible.

A rare and unusual complication of the STING procedure.

An 8-year-old boy underwent a STING procedure for vesicoureteric reflux. 11 years later, at 19-years-old he presented with the passage of sediment per urethra every 7 weeks. CT scan demonstrated a lesion at the right VUJ. Cystoscopy revealed a 2cm suburothelial mass adjacent to the VUJ, with normal urothelium overlying it. Resection of the area revealed a white plastic-like substance, consistent with the bulking agent Deflux, which was scraped away. The patient made an uneventful recovery and at review, 3 months later, is symptom free. Our case demonstrates a rare and unusual complication of the STING procedure. SECTION HEADINGS: Endourology, General Urology, Paediatrics.

Combined flexible URS and percutaneous 'through and through' puncture of an intra-renal cyst with internalisation of drainage, to treat calyceal obstruction and recurrent stones.

A 61 year old gentleman had a large renal cyst, thought to be causing a 'pseudo-hydrocalyx' leading to recurrent stones. Definitive treatment with laparoscopic deroofing was planned, however intra-operatively this was abandoned due to complex anatomy and scared adherent tissue. Patient went on to have a flexible ureteroscopy and 'through and through' puncture of an intrarenal cyst with PCNL to treat his stones and renal cyst simultaneously. CT scan 12 months later showed no new stone formation and no residual cyst. Percutaneous puncture of a renal cyst combined with flexible ureteroscopy is an effective method when treating large renal cysts.