Article
Suppression of finger tremor using dynamic vibration absorbers
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Authors
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Masashi Matsuta
- Department of Orthopaedic Surgery, Kanazawa University, Ishikawa Kanazazwa Takaramachi, Japan
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Kaoru Tada
- Department of Orthopaedic Surgery, Kanazawa University, Ishikawa Kanazazwa Takaramachi, Japan
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Tadahiro Nakajima
- Department of Orthopaedic Surgery, Kanazawa University, Ishikawa Kanazazwa Takaramachi, Japan
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Mika Nakada
- Department of Orthopaedic Surgery, Kanazawa University, Ishikawa Kanazazwa Takaramachi, Japan
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Hiroyuki Tsuchiya
- Department of Orthopaedic Surgery, Kanazawa University, Ishikawa Kanazazwa Takaramachi, Japan
| Published: | February 6, 2020 |
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Outline
Text
Objectives/Interrogation: A major impediment to precise microscope operation is finger tremor. We evaluated tremor and investigated tremor suppression using dynamic vibration absorbers.
Methods: Postural tremor: We evaluated postural tremor in 10 healthy men (average age: 22.7 years). Piezoelectric elements were attached to the dorsal and radial sides of the index fingers. The palmar bases of the fingers were attached to supports, and the fingers were held in extension. We processed acceleration with an amplifier and analyzer and evaluated the time base waveform and frequency characteristics of biaxial tremors.
Intention tremor suppression: We evaluated intention tremor in 10 healthy men (average age: 22.7 years). Subjects gripped a 30-G needle with a needle holder for microsurgery and held the needle tip in the lumen of an 18-G needle under the microscope. We evaluated tremor perpendicular to the nail surface. A passive type dynamic vibration absorber with a weight that induced 10-Hz natural frequency was prepared. Dynamic vibration absorbers were attached perpendicular to the nail surface, and tremor with or without attachments was evaluated. An active type dynamic vibration absorber with active damping force produced by external energy was prepared. Tremor was evaluated in 8 orthopedic surgeons (average age: 33.6 years) in the same manner as for the passive dynamic vibration absorbers.
Results and Conclusions: Postural tremor: The root-mean-square of the time base waveform was calculated, and postural tremor perpendicular to the nail surface was greater than that parallel to the surface. Peak postural tremor frequency was approximately 10 Hz.
Intention tremor suppression: The root-mean-square of the time axis waveform was 0.50 ± 0.09 (V) when a passive type dynamic vibration absorber was not used and 0.46 ± 0.05 (V) when a vibration absorber was used. However, no significant difference was observed. In some cases, the intention tremor showed a peak frequency of approximately 10 Hz. The peak decreased with the use of a passive type dynamic vibration absorber, but in some cases the peak was not clear and in others the decrease in the peak with use of the passive type dynamic vibration absorber was also not clear.
The root-mean-square of the time axis waveform was significantly suppressed to 19.9 ± 3.4 (mV) when an active type dynamic vibration absorber was not used and 18.1 ± 3.5 (mV) when a vibration absorber was used (p = 0.002).
This study investigated an active type dynamic vibration absorber may be effective.
