A Pilot Study of a Novel Syphon Ureteral Access Sheath Shows Potential to Reduce Renal Pressures and Improve Irrigant Flow.

OBJECTIVE: To describe a novel syphon ureteral access sheath (UAS) intended for use during flexible uretero-renoscopy (fURS). We aimed to report on a pilot study as well as intrarenal pressures (IRP) and irrigant flow volumes compared to traditional UAS.

METHODS: Patients undergoing routine fURS for single, <2cm intrarenal nephrolithiasis were identified, and written informed consent was obtained. Irrigation via the fURS was instilled through the novel 11/13 Fr UAS without (a proxy for a traditional UAS) and with the novel syphon box attached. Measured minute irrigant flow volume, steady state and bolus IRP were compared.

RESULTS: Ten participants (6 males and 4 females) were treated with the syphon UAS. All procedures were completed safely without intraoperative complications. The mean baseline IRP with and without the syphon was 18 vs 29 mmHG (P < .001, SD 4.0 vs 4.8). The mean minute irrigant flow volume with and without the syphon was 31 vs 21 ml (P < .001, SD 6.4 vs 3.3). The mean peak IRP following a 10 ml bolus with and without the syphon was 71 vs 104 mmHg (P = .03, SD 74 vs 59).

CONCLUSION: The described novel UAS is different from traditional devices by incorporating a syphon mechanism. This pilot trial demonstrates that the novel syphon UAS may hold clinical potential to reduce IRP and increase irrigant flow compared to traditional UAS. Firm conclusions about efficacy and safety require assessment of the device in a larger clinical trial.