Introduction The aims of this study were to evaluate (1) grasping forces with the application of a tactile feedback system in vivo and (2) the incidence of tissue damage incurred during robotic tissue manipulation. Robotic-assisted minimally invasive surgery has been shown to be beneficial in a variety of surgical specialties, particularly radical prostatectomy. This innovative surgical tool offers advantages over traditional laparoscopic techniques, such as improved wrist-like maneuverability, stereoscopic video displays, and scaling of surgical gestures to increase precision. A widely cited disadvantage associated with robotic systems is the absence of tactile feedback. Methods and procedure Nineteen subjects were categorized into two groups: 5 experts (six or more robotic cases) and 14 novices (five cases or less). The subjects used the da Vinci with integrated tactile feedback to run porcine bowel in the following conditions: ( T 1: deactivated tactile feedback; T 2: activated tactile feedback; and T 3: deactivated tactile feedback). The grasping force, incidence of tissue damage, and the correlation of grasping force and tissue damage were analyzed. Tissue damage was evaluated both grossly and histologically by a pathologist blinded to the sample. Results Tactile feedback resulted in significantly decreased grasping forces for both experts and novices ( P < 0.001 in both conditions). The overall incidence of tissue damage was significantly decreased in all subjects ( P < 0.001). A statistically significant correlation was found between grasping forces and incidence of tissue damage ( P = 0.008). The decreased forces and tissue damage were retained through the third trial when the system was deactivated ( P > 0.05 in all subjects). Conclusion The in vivo application of integrated tactile feedback in the robotic system demonstrates significantly reduced grasping forces, resulting in significantly less tissue damage. This tactile feedback system may improve surgical outcomes and broaden the use of robotic-assisted minimally invasive surgery.

BACKGROUND:Laparoscopic minimally invasive surgery has revolutionized surgical care by reducing trauma to the patient, thereby decreasing the need for medication and shortening recovery times. During open procedures, surgeons can directly feel tissue characteristics. However, in laparoscopic surgery, tactile feedback during grip is attenuated and limited to the resistance felt in the tool handle. Excessive grip force during laparoscopic surgery can lead to tissue damage. Providing additional supplementary tactile feedback may allow subjects to have better control of grip force and identification of tissue characteristics, potentially decreasing the learning curve associated with complex minimally invasive techniques. METHODS:A tactile feedback system has been developed and integrated into a modified laparoscopic grasper that allows forces applied at the grasper tips to be felt by the surgeon's hands. In this study, 15 subjects (11 novices, 4 experts) were asked to perform single-handed peg transfers using these laparoscopic graspers in three trials (feedback OFF, ON, OFF). Peak and average grip forces (newtons) during each grip event were measured and compared using a Wilcoxon ranked test in which each subject served as his or her own control. RESULTS:After activating the tactile feedback system, the novice subject population showed significant decreases in grip force (p < 0.003). When the system was deactivated for the third trial, there were significant increases in grip force (p < 0.003). Expert subjects showed no significant improvements with the addition of tactile feedback (p > 0.05 in all cases). CONCLUSION:Supplementary tactile feedback helped novice subjects reduce grip force during the laparoscopic training task but did not offer improvements for the four expert subjects. This indicates that tactile feedback may be beneficial for laparoscopic training but has limited long-term use in the nonrobotic setting.

Although surgical robotic systems provide several advantages over conventional minimally invasive techniques, they are limited by a lack of tactile feedback. Recent research efforts have successfully integrated tactile feedback components onto surgical robotic systems, and have shown significant improvement to surgical control during in vitro experiments. The primary barrier to the adoption of tactile feedback in clinical use is the unavailability of suitable force sensing technologies. This paper describes the design and fabrication of a thin-film capacitive force sensor array that is intended for integration with tactile feedback systems. This capacitive force sensing technology could provide precise, high-sensitivity, real-time responses to both static and dynamic loads. Capacitive force sensors were designed to operate with optimal sensitivity and dynamic range in the range of forces typical in minimally invasive surgery (0 - 40 N). Initial results validate the fabrication of these capacitive force-sensing arrays. We report 16.3 pF and 146 pF for 1-mm 2 and 9-mm 2 capacitive areas, respectively, whose values are within 3% of theoretical predictions.

While commercial surgical robotic systems have provided improvements to minimally invasive surgery, such as 3D stereoscopic visualization, improved range of motion, and increased precision, they have been designed with only limited haptic feedback. A number of robotic surgery systems are currently under development with integrated kinesthetic feedback systems, providing a sense of resistance to the hands or arms of the user. However, the application of tactile feedback systems has been limited to date. The challenges and potential benefits associated with the development of tactile feedback systems to surgical robotics are discussed. A tactile feedback system, featuring piezoresistive force sensors and pneumatic silicone-based balloon actuators, is presented. Initial tests with the system mounted on a commercial robotic surgical system have indicated that tactile feedback may potentially reduce grip forces applied to tissues and sutures during robotic surgery, while also providing high spatial and tactile resolution.

A tactile feedback system has been developed in order to provide augmentative sensory feedback for a number of medical applications. The key component to the system is a pneumatic balloon-based tactile display, which can be scaled and adapted for a variety of configurations. The system also features pneumatic and electronic control system components, a commercial force sensor modified to fit the desired application. To date, this technology has been successfully applied to medical robotics, minimally invasive surgery, and rehabilitation medicine.

A tactile feedback vest was developed to provide sensory information to patients with balance disorders. The system was designed to detect levels of imbalance that are imperceptible to patients with balance deficit, and to provide intuitive and appreciable sensory feedback that allows for rapid balance correction. Polydimethylsiloxane (PDMS) based pneumatic actuators were clustered on the ventral, dorsal, left and right surfaces of the tactile vest to provide multi-directional sensory feedback. Two biaxial accelerometers were mounted near the shoulder to measure linear and angular acceleration of the upper torso, and a system controller that regulates communication between the sensors and actuators was developed. Actuator deflection was characterized to optimize tactile feedback. Average deflections of 2.6 mm and 7.1 mm were recorded with input pressures of 1.6 psi and 4.0 psi, respectively. In future studies, human perceptual testing will be performed to optimize the system for clinical use.

A complete glove-based master-slave tactile feedback system was developed to provide users with a remote sense of touch. The system features a force-sensing master glove with piezoresistive force sensors mounted at each finger tip, and a pressure-transmitting slave glove with silicone-based pneumatically controlled balloon actuators, mounted at each finger tip on another hand. A control system translates forces detected on the master glove, either worn by a user or mounted on a robotic hand, to discrete pressure levels at the fingers of another user. System tests demonstrated that users could accurately identify the correct finger and detect three simultaneous finger stimuli with 99.3% and 90.2% accuracy, respectively, when the subjects were located in separate rooms. The glove-based tactile feedback system may have application to virtual reality, rehabilitation, remote surgery, medical simulation, robotic assembly, and military robotics.

Lower-limb amputation, whether by trauma or complication of another condition, affects more than 800,000 people in the United States alone. These patient groups typically suffer from decreased mobility and an increased incidence of injury due to fall, even with the application of prosthetic limbs. A haptic feedback system prototype was previously developed to provide augmentative sensory information to patients suffering from total or attenuated lower-limb sensory loss. By providing tactile cues to the user based on plantar pressure distributions, it is hoped that this system can improve rehabilitation and functional outcomes following lower-limb injury. This paper presents an updated system that was fitted to the residual limb of a below-knee amputee, as well as a pilot study using the device. The pilot study demonstrated that the amputee could accurately perceive various tactile stimuli with high accuracy (Gt 87.5%), therefore indicating that the approach is feasible.

A tactile feedback system has been developed using silicone-based pneumatic balloon actuators and piezoelectric force sensors, paired with a pneumatic control system. This system has been fitted directly onto the da Vinci surgical robotic system, allowing the forces applied at the robotic end-effectors to be felt on the fingers of surgeons or other system operators. Preliminary system tests have been performed to evaluate the efficacy of the system and to validate the tactile feedback approach. The actuators and pneumatic system had a sufficiently low footprint such that they did not hinder movements during surgical task performance. Preliminary studies using a pressure-indicating phantom suggested that grip force may be reduced with direct tactile-to-tactile feedback. An additional study found that a six element tactile sensing array can effectively provide spatial information to the fingers. The results of these studies are summarized in this paper.

Many existing refreshable Braille display technologies are costly or lack robust performance. A process has been developed to fabricate consistent and reliable pneumatic balloon actuators at low material cost, using a novel manufacturing process. This technique has been adapted for use in refreshable Braille displays that feature low power consumption, ease of manufacture and small form factor. A prototype refreshable cell, conforming to American Braille standards, was developed and tested. The cell was fabricated from molded PDMS to form balloon actuators with a spin-coated silicone film, and fast pneumatic driving elements and an electronic control system were developed to drive the Braille dots. Perceptual testing was performed to determine the feasibility of the approach using a single blind human subject. The subject was able to detect randomized Braille letters rapidly generated by the actuator with 100% character detection accuracy.

Even after rehabilitation, patients with lower-limb amputation may continue to exhibit suboptimal gait. A wireless telemetry system, featuring force sensors, accelerometers, control electronics and a Bluetooth transmission module was developed to measure plantar pressure information and remotely monitor patient mobility. Plantar pressure characterization studies were performed to determine the optimal sensor placement. Finally, the wireless telemetry system was integrated with a previously developed haptic feedback system in order to allow remote monitoring of patient mobility during haptic system validation trials.

Minimally invasive laparoscopic surgery offers advantages over open procedures, such as improved recovery time, decreased trauma, and decreased hospital expenses. One drawback to laparoscopic surgery is that tactile feedback provided to the hands of the surgeon is attenuated. Additional tactile feedback may allow surgeons to better control grip force and better identify tissue characteristics, potentially decreasing the learning curve associated with laparoscopic surgery. A tactile feedback system has been developed and integrated into a modified laparoscopic grasper, allowing the forces applied at the grasper tips to be felt by the surgeon's hands. Piezoresistive sensors transmit force data to a microcontroller, which then controls a solenoid valve-based pneumatic system. Feedback is provided using silicone-based balloon actuators, which inflate to apply pressure to the surgeon's hand. The actuators are flush with the handles, such that they do not hinder movements during surgical task performance. Preliminary tests have shown successful operation of the system with latency less than 50 ms, high actuation pressures (15 PSI), and high perceptual accuracy of the balloon-based stimuli (> 90%).