Wireless MEMS pressure sensing for intrarenal pressure monitoring during ureteroscopy: an in vitro bench-feasibility study

Introduction Elevated intrarenal pressure (IRP) during retrograde intrarenal surgery is linked to infectious and parenchymal complications, motivating wireless IRP-monitoring devices that do not occupy the ureteroscope working channel. Methods We report an in vitro bench characterization of two units of a wireless silicon piezoresistive microelectromechanical systems pressure sensor coupled to a Bluetooth Low Energy link sampled at 10 Hz. Data were recorded under manual ureteroscope advancement and gravity irrigation at 1.0, 0.75 and 0.5 m, giving 7,630 paired samples. The device supplies digitally reported pressure readings in mmHg. Results Inter-unit agreement was high under manual push and at 1.0 m (Pearson r ≥ 0.996), but a systematic offset emerged at 0.5 m (mean difference –2.61 mmHg, about 40% of the steady-state mean; ICC(2,1) = 0.19 on decimated samples). Peak and steady-state pressures increased monotonically with irrigation height (R 2 = 0.997 across three points, n = 1 per point). Mean steady-state readings were about 16%–26% of the nominal hydrostatic head; this ratio describes the combined sensor–bench system response rather than intrinsic sensor sensitivity. 3-SD noise estimates over 5-s pre-irrigation baselines ranged from about 0.01 to 0.74 mmHg. Discussion Together these findings identify a prominent inter-unit difference at lower hydrostatic head, with offset and proportional components whose magnitude varied between recordings. Reference-manometer validation, replicated multi-height testing, and response-time, temperature and biocompatibility studies form the next steps toward clinical evaluation.