Real-Time Haptic Feedback in Laparoscopic Tools for Use in Gastro-Intestinal Surgery*

Periodic Kinesthetic Guidance Cannot Expedite Learning Surgical Skills

Introduction. Connecting multiple haptic devices in a master-slave fashion enables us to deliver kinesthetic (haptic) feedback from 1 person to another. This study examined whether inter-user feedback delivered from an expert to a novice would facilitate skill acquisition of the novice in learning laparoscopic surgery and expedite it compared to traditional methods. Methods. We recruited fourteen novices and divided them into 1 of 2 training groups with 6 half-hour training sessions. The task was precision cutting adopted from one of the tasks listed in Fundamentals of Laparoscopic Surgery using laparoscopic instruments. In the haptic feedback group (haptic), 8 subjects had the chance to passively feel an expert's performance before they started to practice in each training session. In the self-learning group (control), 6 subjects watched a video before practicing. Each session was video recorded, and task performance was measured by task completion time, number of grasper adjustments, and instrument crossings. Cutting accuracy, defined as the percentage of deviation of the cutting line from the predefined line, was analyzed via computer analysis. Results. Results show no significant difference among performance measures between the 2 groups. Participants performed similarly when practicing alone or with periodic haptic feedback. Discussion. Further research will be needed for improving our way of integrating between-person haptic feedback with skills training protocol.

Electrically-Evoked Proximity Sensation Can Enhance Fine Finger Control in Telerobotic Pinch

For teleoperation tasks requiring high control accuracy, it is essential to provide teleoperators with information on the interaction between the end effector and the remote environment. Real-time imaging devices have been widely adopted, but it delivers limited information, especially when the end effectors approach the target following the line-of-sight. In such situations, teleoperators rely on the perspective at the screen and can apply high force unintentionally at the initial contact. This research proposes to deliver the distance information at teleoperation to the fingertips of teleoperators, i.e., proximity sensation. Transcutaneous electrical stimulation was applied onto the fingertips of teleoperators, with the pulsing frequency inversely proportional to the distance. The efficacy of the proximity sensation was evaluated by the initial contact force during telerobotic pinch in three sensory conditions: vision only, vision + visual assistance (distance on the screen), and vision + proximity sensation. The experiments were repeated at two viewing angles: 30–60° and line-of-sight, for eleven healthy human subjects. For both cases, the initial contact force could be significantly reduced by either visual assistance (20–30%) or the proximity sensation (60–70%), without additional processing time. The proximity sensation is two-to-three times more effective than visual assistance regarding the amount of force reduction.

Real time cancer prediction based on objective tissue compliance measurement in endoscopic surgery

OBJECTIVE

To investigate the feasibility of real time cancer tissue diagnosis intraoperatively based on in vivo tissue compliance measurements obtained by a recently developed laparoscopic smart device.

BACKGROUND

Cancer tissue is stiffer than its normal counterpart. Modern forms of remote surgery such as laparoscopic and robotic surgical techniques diminish direct assessment of this important tissue property. In vivo human tissue compliance of the normal and cancer gastrointestinal tissue is unknown. A Clinical Real Time Tissue Compliance Mapping System (CRTCMS) with a predictive power comparable to the human hand and useable in routine surgical practice has been recently developed.

METHODS

The CRTCMS is employed in the operating theater to collect data from 50 patients undergoing intra-abdominal surgical interventions [40 men, 10 women, aged between 32 and 89 (mean = 66.4, range = 57)]. This includes 10 esophageal and 27 gastric cancer patients. A total of 1212 compliance measurements of normal and cancerous in vivo gastrointestinal tissues were taken. The data were used to calibrate the CRTCMS to predict cancerous tissue in a further 12 patients (3 cancer esophagus and 9 cancer stomach) involving 175 measurements.

RESULTS

The system demonstrated a high prediction power to diagnose cancer tissue in real time during routine surgical procedures (sensitivity = 98.7%, specificity = 99%). An in vivo human tissue compliance data bank of the gastrointestinal tract was produced.

CONCLUSIONS

Real time cancer diagnosis based on in vivo tissue compliance measurements is feasible. The reported data open new avenues in cancer diagnostics, surgical robotics, and development of more realistic surgical simulators.

Reviewing the technological challenges associated with the development of a laparoscopic palpation device

Minimally invasive surgery (MIS) has heralded a revolution in surgical practice, with numerous advantages over open surgery. Nevertheless, it prevents the surgeon from directly touching and manipulating tissue and therefore severely restricts the use of valuable techniques such as palpation. Accordingly a key challenge in MIS is to restore haptic feedback to the surgeon. This paper reviews the state-of-the-art in laparoscopic palpation devices (LPDs) with particular focus on device mechanisms, sensors and data analysis. It concludes by examining the challenges that must be overcome to create effective LPD systems that measure and display haptic information to the surgeon for improved intraoperative assessment.

An integrated pneumatic tactile feedback actuator array for robotic surgery

BACKGROUND

A pneumatically controlled balloon actuator array has been developed to provide tactile feedback to the fingers during robotic surgery.

METHODS

The actuator and pneumatics were integrated onto a robotic surgical system. Potential interference of the inactive system was evaluated using a timed robotic peg transfer task. System performance was evaluated by measuring human perception of the thumb and index finger.

RESULTS

No significant difference was found between performance with and without the inactive mounted actuator blocks. Subjects were able to determine inflation location with > 95% accuracy and five discrete inflation levels with both the index finger and thumb with accuracies of 94% and 92%. Temporal tests revealed that an 80 ms temporal separation was sufficient to detect balloon stimuli with high accuracy.

CONCLUSIONS

The mounted balloon actuators successfully transmitted tactile information to the index finger and thumb, while not hindering performance of robotic surgical movements.

Tactile Feedback Induces Reduced Grasping Force in Robot-Assisted Surgery

Robot-assisted minimally invasive surgery has gained widespread use over the past decade, but the technique is currently operated in the absence of haptic feedback during tissue manipulation. We have developed a complete tactile feedback system, consisting of a piezoresistive force sensor, control system, and pneumatic balloon tactile display, and mounted directly onto a da Vinci surgical robotic system. To evaluate the effect of tactile feedback on robotic manipulation, a group of novices (n = 16) and experts ( n = 4) were asked to perform three blocks of peg transfer tasks with the tactile feedback system in place. Force generated at the end-effectors was measured in all three blocks, but tactile feedback was active only during the middle block. All subjects used higher force when the feedback system was inactive. When active, subjects immediately used substantially less force and still maintained appropriate grip during the task. After the system was again turned off, grip force increased significantly to prefeedback levels. These results demonstrate that robotic manipulations without tactile feedback are done with more force than needed to grasp objects. Therefore, the addition of tactile feedback allows the surgeon to grasp with less force, and may improve control of the robotic system and handling of tissues and other objects.