Development of an apparatus and procedure for evaluating the efficiency of nasal irrigation

Background Although different methods of nasal irrigation have been utilized, irrigation efficiency in nasal cavities has not been well assessed. The objective of this study was to develop an apparatus and procedure for evaluating the irrigation efficiency and to explore the optimal head position during irrigation. Methods Casts of the left sinonasal cavity from a healthy volunteer were made from high-resolution-computed tomography data using 3D printing with composite materials. An adjustable apparatus that allowed cast fixation at the different head positions was built. The yogurt was used to simulate mucus. The cast with 5 ml yogurt filled around the superior, middle, and inferior turbinate was fixed in six head positions including head tilt 10 degrees, 45 degrees, and 60 degrees forward with or without leaning 30 degrees to the right. The cast was irrigated with 120 ml, 175 ml, and 240 ml dyed water and was video recorded. The irrigation efficiency was calculated based on the weight difference of the cast before and after the irrigation. Results Most residual yogurt was located around the superior meatus after the irrigation under different volumes and head positions. The irrigation efficiency of the rinse bottle or the pulsatile device was volume dependent, with the highest irrigation efficiency under 240 ml water. When the left sinonasal cavity was irrigated, the head position of tilt 45 degrees forward with leaning 30 degrees to the right was the optimal head position for these two devices when compared to other positions. The pulsatile device with 240 ml water performed better than the rinse bottle with 240 ml water regarding the irrigation efficiency under the optimal head position (0.8700 +/- 0.0138 vs 0.7536 +/- 0.0099, p = 0.003). Conclusions The developed apparatus provided a potential method for evaluating the irrigation efficiency. The head position of tilt 45 degrees forward with leaning 30 degrees was suitable for patients to perform the nasal irrigation.