Robot-assisted microsurgical forceps with haptic feedback for transoral laser microsurgery

Design and Modeling of a Three-Degree-of-Freedom Articulating Robotic Microsurgical Forceps for Trans-Oral Laser Microsurgery

Trans-oral laser microsurgery (TLM) is a surgical procedure for removing malignancies (e.g., cysts, polyps, tumors) of the laryngeal region through laser ablation. Intraoperative microsurgical forceps (i.e., microforceps) are used for tissue manipulation. The microforceps are rigid, single degree-of-freedom (DOF) devices (open–close) with precurved jaws to access different parts of the curved cylindrical laryngeal region. These microforceps are manually handled and are subject to hand tremors, poor reachability, and nonergonomic use, resulting in poor efficacy and efficiency in the surgery. A novel 3DOF motorized microforceps device is presented here, integrated with a 6DOF serial robotic manipulator. The device, referred to as RMF-3, offers three motorized DOFs: (i) open–close forceps jaw; (ii) tool rotation; and (iii) tool-tip articulation. It is designed to be compliant with TLM spatial constraints. The manual handling is replaced by tele-operation device, the omega.7. The design of the RMF-3 is characterized through theoretical and experimental analysis. The device shows a maximum articulation of 38 deg and tool rotation of 100 deg. Its performance is further evaluated through user trials using the ring-in-loop setup. The user trials demonstrate benefits of the 3DOF workspace of the device along with its teleoperation control. RMF-3 offers an improved workspace and reachability within the laryngeal region. Surgeons, in their preliminary evaluation of the device, appreciated the ability to articulate the tip, along with rotation, for hard-to-reach parts of the surgical site. RMF-3 offers an ergonomic robotic teleoperation control interface which overcomes hand tremors and extreme wrist excursion which leads to surgeon pain and discomfort.

A robotic microsurgical forceps for transoral laser microsurgery

PURPOSE

In transoral laser microsurgery (TLM), the close curved cylindrical structure of the laryngeal region offers functional challenges to surgeons who operate on its malignancies with rigid, single degree-of-freedom (DOF) forceps. These challenges include surgeon hand tremors, poor reachability, poor tissue surface perception, and reduced ergonomy in design. The integrated robotic microsurgical forceps presented here is capable of addressing the above challenges through tele-operated tissue manipulation in TLM.

METHODS

The proposed device is designed in compliance with the spatial constraints in TLM. It incorporates a novel 2-DOF motorized microsurgical forceps end-effector, which is integrated with a commercial 6-DOF serial robotic manipulator. The integrated device is tele-operated through the haptic master interface, Omega.7. The device is augmented with a force sensor to measure tissue gripping force. The device is called RMF-2F, i.e. robotic microsurgical forceps with 2-DOF end-effector and force sensing. RMF-2F is evaluated through validation trials and pick-n-place experiments with subjects. Furthermore, the device is trialled with expert surgeons through preliminary tasks in a simulated surgical scenario.

RESULTS

RMF-2F shows a motion tracking error of less than 400 μm. User trials demonstrate the device's accuracy in task completion and ease of manoeuvrability using the Omega.7 through improved trajectory following and execution times. The tissue gripping force shows better regulation with haptic feedback (1.624 N) than without haptic feedback (2.116 N). Surgeons positively evaluated the device with appreciation for improved access in the larynx and gripping force feedback.

CONCLUSIONS

RMF-2F offers an ergonomic and intuitive interface for intraoperative tissue manipulation in TLM. The device performance, usability, and haptic feedback capability were positively evaluated by users as well as expert surgeons. RMF-2F introduces the benefits of robotic teleoperation including, (i) overcoming hand tremors and wrist excursions, (ii) improved reachability and accuracy, and (iii) tissue gripping feedback for safe tissue manipulation.