Design and Bench Validation of a Mechanical Intravaginal Dynamometer Mechanism

Abstract

Strength and tone of the pelvic floor muscles are thought to play an important role in pelvic floor disorders, and are key outcomes monitored in pelvic floor rehabilitation, yet the standard approach to measuring these outcomes is through subjective assessment using manual palpation. While intravaginal dynamometers (IVD) have been designed to measure these characteristics in research settings, most are not sufficient to withstand the rigors of clinical use. This work presents the bench validation and subsequent updated design of a new mechanical constant speed mechanism for future inclusion in an IVD. Opening speeds of the original mechanism were validated with and without external loading using video analysis. The bench validation showed that the speed of arm opening was lower than the ranges specified for clinical use and was influenced by external loading. The mechanism was updated, and the bench test was repeated. The updated mechanism was found to provide output speeds that are within the ranges required clinically and were minimally impacted by external loading. The next step of this work is to reduce the size of the mechanism and improve output speeds to allow it to be assembled into a clinical prototype IVD.