AIM: Design and develop an automated, hand-held instrument (elastometer) to assess in vivo passive stiffness of the pelvic floor muscle. MATERIALS AND METHODS: The elastometer system consisted of a hand piece, real-time controller, and laptop computer. A cable connected the hand-piece to the controller, which communicated with a laptop computer via an ethernet connection. Force sensitivity calibration and displacement accuracy were determined experimentally using a spring load and an Instron mechanical tester. A test re-test series quantified the in vivo repeatability (within a procedure) and reproducibility (between procedures after a 5 min delay) of passive stiffness in volunteers (n = 20). Stiffness was determined from the gradient of the force-displacement curve for each cycle. RESULTS: The force-aperture spring measurements from the elastometer showed consistent (r(2) = 1.0000) agreement with those measured by the Instron. The difference between spring stiffness as measured by the elastometer and the Instron (388.1 N/m cf. 388.5 N/m, respectively) was negligible. The intra-class correlation coefficient for repeatability within procedures was 0.986 95% CI (0.964-0.994) n = 20, and reproducibility between procedures ICC 0.934 (95% CI 0.779-0.981) n = 12. Bland-Altman analysis determined a bias of 0.3 and 18.5 N/m, for repeatability and reproducibility respectively. Neither bias is likely to be clinically significance. CONCLUSION: The elastometer demonstrated very good repeatability and accuracy in the measurement of force/displacement during in vitro testing. There was a high degree of repeatability and reproducibility in stiffness measurements in a test re-test series. Our results demonstrate the elastometer is accurate and reliable and thereby suitable for larger clinical trials.
AIM: Design and develop an automated, hand-held instrument (elastometer) to assess in vivo passive stiffness of the pelvic floor muscle. MATERIALS AND METHODS: The elastometer system consisted of a hand piece, real-time controller, and laptop computer. A cable connected the hand-piece to the controller, which communicated with a laptop computer via an ethernet connection. Force sensitivity calibration and displacement accuracy were determined experimentally using a spring load and an Instron mechanical tester. A test re-test series quantified the in vivo repeatability (within a procedure) and reproducibility (between procedures after a 5 min delay) of passive stiffness in volunteers (n = 20). Stiffness was determined from the gradient of the force-displacement curve for each cycle. RESULTS: The force-aperture spring measurements from the elastometer showed consistent (r(2) = 1.0000) agreement with those measured by the Instron. The difference between spring stiffness as measured by the elastometer and the Instron (388.1 N/m cf. 388.5 N/m, respectively) was negligible. The intra-class correlation coefficient for repeatability within procedures was 0.986 95% CI (0.964-0.994) n = 20, and reproducibility between procedures ICC 0.934 (95% CI 0.779-0.981) n = 12. Bland-Altman analysis determined a bias of 0.3 and 18.5 N/m, for repeatability and reproducibility respectively. Neither bias is likely to be clinically significance. CONCLUSION: The elastometer demonstrated very good repeatability and accuracy in the measurement of force/displacement during in vitro testing. There was a high degree of repeatability and reproducibility in stiffness measurements in a test re-test series. Our results demonstrate the elastometer is accurate and reliable and thereby suitable for larger clinical trials.
Authors: Christopher J Hillary; Sabiniano Roman; Anthony J Bullock; Nicola H Green; Christopher R Chapple; Sheila MacNeil Journal: PLoS One Date: 2016-03-16 Impact factor: 3.240
Authors: Dilly O C Anumba; Siobhán Gillespie; Swati Jha; Shahram Abdi; Jenny Kruger; Andrew Taberner; Poul M F Nielsen; Xinshan Li Journal: Int Urogynecol J Date: 2019-12-04 Impact factor: 2.894