Vibration testing of laparoscopic surgical instruments under varying grip pressures
Many devices use vibration to provide sensory cues to a human user. In applications, such as smart phones, the vibratory sensory cue is somewhat simple and needs only to exceed a known threshold to signal the user; however, applications that require an individual to control or manipulate an instrument while being given a vibratory sensory cue must also consider the excitation, whose primary purpose is to provide vibrotactile feedback, which can alter the user’s ability to properly control or maneuver the instrument. Another consideration for many handheld instruments is that a user’s grip pressure can drastically alter the instrument’s dynamic response. To this end, predicting the instrument’s response is made difficult, because the relationships between grip pressure and the equivalent interfacial damping and stiffness is complex. To address this research gap, this paper explores the idea of performing experimental vibration tests on a laparoscopic instrument while being held at varying grip pressures. This research is motivated by the idea of providing vibratory feedback through laparoscopic surgical instruments. A gap in the literature exists in understanding how surgeon grip characteristics impact the optimal frequency for which this excitation should be supplied. Results from this study indicate that excitation frequencies should be greater than 175Â Hz for both weak and strong grip configurations. Lower frequencies result in a larger amplitude response at the instrument tip for all grip pressures, which could result in patient harm as the instrument tip oscillates uncontrollably.
