Resilience of disposable endoscope optical fiber properties after repeat sterilization

The PolyScope(®) (Lumenis, Santa Clara, CA) is a disposable flexible ureteroscope composed of a single-use flexible catheter and a reusable fiber optic bundle. We tested the resilience of the optical properties of the reusable optical fiber after repeat sterilization.

Optical properties evaluated were resolution, distortion, and light transmission. Two different optical fibers were tested, one for each sterilization method. Measurements on each fiber were obtained at baseline and were repeated after each set of 10 sterilization cycles for a total of 100 cycles. To measure resolution, the 1951 USAF Contrast Resolution Chart Target was used to subjectively identify the clearest image on the grid by two different operators. To measure distortion, three images of the distortion grid target were captured with a digital camera and analyzed within Image Pro Plus Software. Light transmission was measured using a digital light meter at 50% and 100% transmission.

There was no significant difference in resolution after 100 sterilization cycles between either Steris or Sterrad NX. Distortion changed by 8.7% and 11.2% for Steris and Sterrad NX, respectively. For Steris at 100% light transmission, baseline was 59 foot-candles and this increased to 85 foot-candles after 100 cycles. For Sterrad NX at 100% light transmission, baseline was 50 foot-candles and this increased to 92 foot-candles after 100 cycles. Results were similar at 50%. There was no significant difference between groups at 50%, 100%, or between sterilization modalities.

The PolyScope fiber optic bundle appears durable after 100 cycles of sterilization with either Steris or Sterrad NX.