ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS
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2003
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ndltd-OhioLink-oai-etd.ohiolink.edu-ucin10529351312021-08-03T06:09:02Z ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS VAITEKUNAS, JEFFREY J. ultrasound surgery medical device tissue cutting Langevin stack In spite of the proven efficacy and safety of ultrasonic surgical systems, the mechanisms for cutting and coagulation are not well understood. Preferred operating parameters and ranges should be used if clinical benefit can be shown. Therefore this research was designed to determine whether frequency, normal force, velocity and blade shape affect the cut-rate of an ultrasonic surgical instrument. Test velocities covered the range available from current ultrasonic surgical systems. Three values for normal force were selected based on previous testing. A low value corresponded to a "light" touch typically applied in fine dissection between tissue planes, and a heavy value typically used in skin incisions such as a laparotomy. Two specimens were chosen for evaluation: wax and liver. The basic behaviors of the observed cut-rates obtained at 55.5 kHz with a 2.1 mm diameter round blade were similar for wax and liver. Using analysis of variance (ANOVA), normal force, ultrasonic velocity and their first order interaction are shown to significantly affect cut-rate up to 5 N in wax and 2.5 N in liver. In wax, cut-rate is shown to be independent of frequency, and in liver the data indicate that cut-rate is independent of frequency, but are not sufficient to draw a statistical conclusion. In liver above a threshold, cut-rate increases significantly and depends on blade shape. A model for wax cutting was developed based on melting and removal of wax. Several assumptions were made and two parameters were determined by a regression. Still, the model predictions were accurate for the data on which the regression was performed. The model also predicts with reasonable accuracy the behavior observed at other frequencies for other blade shapes. The model can certainly be improved by more rigorous development; nonetheless, it does demonstrate the basic mechanisms involved in wax cutting. The results from the liver experiments and data analysis suggest that much more work is needed to accurately determine the underlying mechanisms of complex behavior of cutting tissue. The outcome of this research on liver cutting is the identification of promising directions for future research. 2003-07-07 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1052935131 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1052935131 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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language |
English |
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topic |
ultrasound surgery medical device tissue cutting Langevin stack |
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ultrasound surgery medical device tissue cutting Langevin stack VAITEKUNAS, JEFFREY J. ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS |
author |
VAITEKUNAS, JEFFREY J. |
author_facet |
VAITEKUNAS, JEFFREY J. |
author_sort |
VAITEKUNAS, JEFFREY J. |
title |
ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS |
title_short |
ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS |
title_full |
ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS |
title_fullStr |
ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS |
title_full_unstemmed |
ULTRASONIC SURGICAL INSTRUMENTS: A MULTI-VARIATE STUDY FOR CUTTING-RATE EFFECTS |
title_sort |
ultrasonic surgical instruments: a multi-variate study for cutting-rate effects |
publisher |
University of Cincinnati / OhioLINK |
publishDate |
2003 |
url |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1052935131 |
work_keys_str_mv |
AT vaitekunasjeffreyj ultrasonicsurgicalinstrumentsamultivariatestudyforcuttingrateeffects |
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1719431737132449792 |