Stephen Kin Yong Chang

A Robotic System for Overlapping Radiofrequency Ablation in Large Tumor Treatment

Overlapping radiofrequency ablation (RFA) in large tumor treatment requires multiple insertions of electrodes, which often compromise its efficacy and predictability. Surgical robot is a promising candidate for the execution of multiple RFA in large tumor treatment in terms of accuracy and speed. In this paper, we share our experience of design and implementation of a novel robotic system specialized for overlapping RFA. It consists of two components: a robotic manipulator and an automatic ablation planning module. The manipulator architecture is designed to facilitate the kinematic requirement for the multiple overlapping ablation technique within the constraints of minimally invasive surgery. An efficient “Voxel Growing” algorithm is adopted to automatically produce the ablation points according to the tumors profile. The feasibility of the proposed robotic system is demonstrated by extensive simulation- and experiment-based evaluation conducted on ex vivo porcine liver.

Interim report: a randomized controlled trial comparing postoperative pain in single-incision laparoscopic cholecystectomy and conventional laparoscopic cholecystectomy.

Single‐incision laparoscopic cholecystectomy (SILC) is increasingly practiced, but there have been no well‐powered randomized trials investigating the technique. This non‐inferiority trial aims to compare SILC with conventional four‐port laparoscopic cholecystectomy (LC) with postoperative pain as the primary endpoint.

Single Port Laparoscopic Liver Resection for Hepatocellular Carcinoma: A Preliminary Report

Single port laparoscopic surgery is an emerging technique, now commonly used in cholecystectomy. The experience of using this technique in liver resection for hepatocellular carcinoma is described in a series of 3 cases with single port laparoscopic liver resection performed during 2010. All patients were male aged 61 to 70 years, with several comorbidities. There were no complications in this early series. The length of hospital stay was 3–5 days. The blood loss was 200–450 mL, with operating time between 142 and 171 minutes. We conclude that this technique is feasible and safe to perform in experienced centers.

Intraoperative visual guidance and control interface for augmented reality robotic surgery

We proposed an augmented reality (AR) robotic system equipped with intraoperative visual guidance and gesture based control interface. The proposed feature is an enhancement of our AR robotic system. AR robotic system was introduced to the field of interventional medicine to assist surgeons in implementing medical operations under the augmented reality environment. The technique combining dextrous robot and AR guidance provides a new operational mode for surgeons. The introduction of robotic modules is to compliment surgeons dexterity and to perform specific tasks defined during the surgery. Augmented reality provides additional visualization and interaction absence in a typical clinical environment. The interfacing system includes intraoperative tracking of surgical tools and virtual reconstruction of the visually occluded tool segment, and an intuitive gesture-based human-computer interaction centered on the projected organ. Preliminary experiments show that this novel human-machine interface is effective for surgical intervention.

Integrated ablation and division device for liver resection.

BACKGROUND Intraoperative blood loss during liver resection may be minimized by ablating the liver parenchyma using radiofrequency (RF) energy. However, it is difficult to estimate the depth of the avascular plane and more RF energy than necessary may be inadvertently used as a result of lack of feedback. METHODS Laparoscopic liver resection was performed on a live porcine model to determine the feasibility and applicability of a model which integrates ablation and division in a single device. RESULTS Liver resection was uncomplicated with minimal bleeding. The integration of the ablation and division mechanism resolved the difficulty of estimating the depth of the avascular plane after coagulation. The real-time feedback mechanism minimized liver damage by eliminating the application of unnecessary RF. CONCLUSIONS The proposed model is functionally acceptable and represents a possible method of determining the depth of the avascular plane and the amount of RF energy required during liver resection.

Image-guided robotic system for radiofrequency ablation of large liver tumor with single incision

Radiofrequency (RF) ablation surgery is effective in liver tumor treatment with non-collateral damage and reduced blood loss. However, the surgery is challenging for large tumor ablation in a minimally invasive procedure. In this paper, we developed a surgical robot system incorporating medical image information and surgeons planning knowledge to realize a minimally invasive procedure for large liver tumor treatment through a single incision. The system includes a surgical robot designed with spherical arc structures, medical image processing and planning, and trajectory generation modules. With planning strategies applied to medical images, multiple trajectories are automatically generated. ex-vivo and in-vivo tests were conducted and the experimental results demonstrated that the multiple RF needle insertion could accurately reach the target area and the required needle incision ports were significantly reduced.