Effect of laparoscopic grasper force transmission ratio on grasp control

BackgroundSurgeons may cause tissue damage by incorrect laparoscopic pinch force control. Unpredictable tissue and grasper properties may cause slips or ruptures. This study investigated how different forms of haptic feedback influence the surgeon’s ability to generate a safe laparoscopic grasp while pulling tissues of variable stiffness using graspers with different force transmission ratios. The results will help define design requirements for training facilities and instruments.MethodsFor this study, 10 participants lifted an object barehanded, with tweezers, or with one of two laparoscopic graspers until they where able to complete five consecutive safe lifts under different tissue stiffness conditions. The participants were presented with indirect visual feedback of pinch force, object location, and target location.ResultsLifting with instruments (tweezers or graspers) required 4.5 to 14.5 times as many practice trials as barehanded lifting, where no slips were recorded. Additionally, slips occurred more often with a decreasing force transmission ratio of the graspers and with increasing tissue stiffness. The maximal pinch force was higher in lifting with instruments than in barehanded lifting (26–60%) irrespective of the stiffness conditions. Using a grasper, the slip margin often was not high enough in the stiffest condition, resulting in slippage of up to 84%.ConclusionsWithout the direct tactile feedback that occurs with normal skin–tissue contact, subjects using graspers have trouble anticipating slippage when lifting tissue with variable stiffness. Performance drops with a decreased force transmision ratio of the instrument and increased tissue stiffness. Furthermore, the pinch forces are not adapted to the variable stiffness conditions. The same pinch force is applied irrespective of tissue stiffness. It takes participants longer to learn a safe laparoscopic grasp than to learn barehanded lifts. Additionally, to perform safe laparoscopic surgery, care should be taken when graspers with a low force transmission ratio are used.

[1]  R. Johansson,et al.  Somatosensory control of precision grip during unpredictable pulling loads , 1992, Experimental Brain Research.

[2]  J. Dankelman,et al.  Haptics in minimally invasive surgery – a review , 2008, Minimally invasive therapy & allied technologies : MITAT : official journal of the Society for Minimally Invasive Therapy.

[3]  R. Johansson,et al.  Signals in tactile afferents from the fingers eliciting adaptive motor responses during precision grip , 2004, Experimental Brain Research.

[4]  K. J. Cole,et al.  Friction at the digit-object interface scales the sensorimotor transformation for grip responses to pulling loads , 2004, Experimental Brain Research.

[5]  P Jenmalm,et al.  Visual and tactile information about object-curvature control fingertip forces and grasp kinematics in human dexterous manipulation. , 2000, Journal of neurophysiology.

[6]  P Jenmalm,et al.  Visual and Somatosensory Information about Object Shape Control Manipulative Fingertip Forces , 1997, The Journal of Neuroscience.

[7]  J. Dankelman,et al.  The optimal mechanical efficiency of laparoscopic forceps , 2004, Surgical Endoscopy.

[8]  Cornelis A. Grimbergen,et al.  Force transmission of laparoscopic grasping instruments , 1997 .

[9]  T. Lejeune,et al.  Importance of cutaneous feedback in maintaining a secure grip during manipulation of hand-held objects. , 2003, Journal of neurophysiology.

[10]  Allan M Smith,et al.  The effects of digital anesthesia on force control using a precision grip. , 2003, Journal of neurophysiology.

[11]  Jenny Dankelman,et al.  Effectiveness of grasping and duration of clamping using laparoscopic graspers , 2001, Surgical Endoscopy And Other Interventional Techniques.

[12]  C. J. Winstein,et al.  Influences of object weight and instruction on grip force adjustments , 2004, Experimental Brain Research.

[13]  Lawrence W. Stark,et al.  Sensing and Manipulation Problems in Endoscopic Surgery: Experiment, Analysis, and Observation , 1993, Presence: Teleoperators & Virtual Environments.

[14]  G. Picod,et al.  What can the operator actually feel when performing a laparoscopy? , 2003, Surgical Endoscopy And Other Interventional Techniques.

[15]  Jenny Dankelman,et al.  Inter- and intraindividual variabilities of perforation forces of human and pig bowel tissue , 2003, Surgical Endoscopy And Other Interventional Techniques.

[16]  A. M. Wing,et al.  Grip force dynamics in the approach to a collision , 1999, Experimental Brain Research.

[17]  J. Flanagan,et al.  Grip-load force coupling: a general control strategy for transporting objects. , 1994, Journal of experimental psychology. Human perception and performance.

[18]  J. Perreault,et al.  Effects of experience on force perception threshold in minimally invasive surgery , 2008, Surgical Endoscopy.

[19]  J. Dankelman,et al.  Friction dynamics of trocars , 2006, Surgical Endoscopy.

[20]  Alice G Witney,et al.  Internal models for bi-manual tasks. , 2004, Human movement science.

[21]  R. S. Johansson,et al.  Roles of glabrous skin receptors and sensorimotor memory in automatic control of precision grip when lifting rougher or more slippery objects , 2004, Experimental Brain Research.

[22]  J. L. Herder,et al.  Forces and displacements in colon surgery , 2002, Surgical Endoscopy And Other Interventional Techniques.