Restoring Haptic Feedback in NOTES Procedures with a Novel Wireless Tissue Stiffness Probe

In the past two decades, several instruments have been developed to overcome the loss of haptic sensation in minimally invasive surgery (MIS). Unfortunately, none of the proposed instruments has been clinically adopted or utilized in natural orifice translumenal endoscopic surgery (NOTES) procedures. The challenge is that NOTES instruments require mounting upon flexible endoscopes thus altering endoscope flexibility and dexterity. We have developed a novel wireless tissue stiffness probe (WTSP) that can be used with a flexible endoscope and create a real-time stiffness distribution map with potential to restore haptic sensation in NOTES. The aim of our study was to assess the performance and feasibility of the WTSP in an ex vivo trial (three phantom models of different elasticity; comparing discrimination of human touch with the WTSP) and in an in vivo trans-colonic access NOTES procedure. Overall, the WTSP was able to detect the stiffness of the three phantoms with a relative error smaller than 3% and a success rate of 100% versus 95% when compared to human perception. The novel WTSP was successful in providing the operator with tactile and kinesthetic feedback for accurate discrimination between tissue phantoms. In vivo tissue palpation was feasible using the WTSP in a trans-colonic NOTES procedure. The WTSP did not encumber the maneuverability or dexterity of the flexible endoscope. This innovative approach to tissue palpation has the potential to open a new paradigm in the field of NOTES where no mechanical link between the external platform and the target region exists.