Hepatobiliary cancers. Clinical practice guidelines in oncology.
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Humans↗
Biomedical subjects
Mika Sinanan
Publications and source records attributed to Mika Sinanan.
Control system architecture for a minimally invasive surgical robot.
As the field of surgical robotics continues to evolve, it is important to keep patient safety in mind. This paper describes a safety control architecture aimed at moving an experimental system in the direction of intrinsically safe operation. The system includes safety features such as: a small number of states, Programmable Logic Controller (PLC) state transition control, active enable, brakes, E-STOP, and a surgeon foot pedal.
Humans↗
Spherical mechanism analysis of a surgical robot for minimally invasive surgery -- analytical and experimental approaches.
Recent advances in technology have led to the fusion of MIS techniques and robot devices. However, current systems are large and cumbersome. Optimizing the surgical robot mechanism will eventually lead to its integration into the operating room (OR) of the future becoming the extended presence of the surgeon and nurses in a room occupied by the patient alone. By optimizing a spherical mechanism using data collected in-vivo during MIS procedures, this study is focused on a bottom-up approach to developing a new class of surgical robotic arms while maximizing their performance and minimizing their size. The spherical mechanism is a rotational manipulator with all axes intersecting at the center of the sphere. Locating the rotation center of the mechanism at the MIS port makes this class of mechanism a suitable candidate for the first two links of a surgical robot for MIS. The required dexterous workspace (DWS) is defined as the region in which 95% of the tool motions are contained based on in-vivo measurements. The extended dexterous workspace (EDWS) is defined as the entire abdominal cavity reachable by a MIS instruments. The DWS is defined by a right circular cone with a vertex angle of 60 degrees and the EDWS is defined by a cone with an elliptical cross section created by two orthogonal vertex angles of 60 degrees and 90 degrees. A compound function based on the mechanism's isotropy and the mechanism stiffness was considered as the performance metric cost function. Optimization across both the DWS and the EDWS lead to a serial mechanism configuration with link length angles of 74 degrees and 60 degrees for a serial configuration. This mechanism configuration maximized the kinematic performance in the DWS while keeping the EDWS as its reachable workspace. Surgeons, using a mockup of two mechanisms in a MIS setup, validated these results experimentally. From these experiments the serial configuration was deemed most applicable for MIS robotic applications compared to a parallel mechanism configuration. The mechanical design of a cable actuated surgical robot was based on optimized link length angles. The system is currently being integrated into a fully operated two-arm system. Small form-factor surgical robotic arms with optimized dexterous workspaces will facilitate the integration of multiple arms while avoiding self-collision in the OR of the future.
Robotics↗
Does the use of a flap during abdominoperineal resection decrease pelvic wound morbidity?
We hypothesized that the use of muscle flaps, known as tissue transfer (TT), at the time of abdominoperineal resection (APR) reduces perineal wound complications. A restrospective review of patients undergoing an APR at the University of Washington (1984-2003) was conducted. Perineal wound complications and eventual wound healing were compared in patients with and without TT. Ninety-two patients (mean age, 56.6 years) underwent APR; 23.9 per cent (n = 22) had concurrent TT. Patients undergoing TT were more likely to have cancer (91% vs. 77%, P = 0.05) and radiation therapy (86% vs. 52%, P < 0.01). Operative times were nearly 2 hours longer in patients having TT (7.4 hours +/- 2.5 hours vs. 5.6 hours +/- 1.8 hours, P = 0.03), but lengths of stay were similar (13 +/- 5.9 days vs. 12 +/- 7.6 days, P = 0.5). Patients undergoing TT had a higher rate of all wound-healing complications (59% vs. 40%, P = 0.1) and major wound-healing complications (32% vs. 26%, P = 0.6). However, these differences were not statistically significant. No differences in major complications were identified in patients with and without preoperative radiation therapy (26% vs. 28%, P = 0.8). Fifteen per cent (n = 14) of all patients failed to heal wounds at 6 months, but only 9 per cent (n = 2) of patients undergoing TT failed to heal their wounds at 6 months compared with 17 per cent (n = 12) in the non-TT group (P = 0.3). After controlling for important covariates, patients undergoing TT during an APR did not have a significantly lower rate of wound complications. The impact of TT on wound healing in patients with recurrent cancer and preoperative radiation therapy is suggestive of a benefit but requires prospective investigation.
Abdomen↗
Minimally invasive surgery task decomposition--etymology of endoscopic suturing.
The analogy between Minimally Invasive Surgery (MIS) and the human language inspires the decomposition of a surgical task into its primary elements. The frequency of different elements or words" and their sequential associations or "grammar" both hold critical information about the process and outcome of the procedure. Modeling these sequential element expressions using a multi finite states model (Markov model) reveals the grammatical structure of the surgical task and is utilized as one of the key steps in objectively assessing surgical performance. The experimental protocol included 30 surgeons at different levels of training (5xR1,R2,R3,R4,R5, and experts) performing Laparoscopic suturing on an animal model (pig). The kinematics and dynamics of left and right endoscopic tools along with the visual view of the surgical scene were acquired by the Blue DRAGON system. The methodology of decomposing the surgical task is based on a fully connected, finite-states (30 states) Markov model (MM) where the left and right hands are represented by 15 states each. In addition to the MM objective analysis, a scoring protocol was used by an expert surgeon to subjectively assess the subjects' technical performance. An objective learning curve was defined based on measuring quantitative statistical distance (similarity) between MM of experts and MM of residents at different levels of training. The objective learning curve (e.g. statistical distance between MM) was similar to that of the subjective performance analysis. The MM proved to be a powerful and compact mathematical model for decomposing a complex task such as laparoscopic suturing. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and dynamics of the surgical tool may benefit from inclusion of the proposed methodology for analysis of efficacy and objective evaluation of surgical skills during training.
Endoscopy↗
Task decomposition of laparoscopic surgery for objective evaluation of surgical residents' learning curve using hidden Markov model.
OBJECTIVE: Evaluation of the laparoscopic surgical skills of surgical residents is usually a subjective process carried out in the operating room by senior surgeons. The two hypotheses of the current study were: (1) haptic information and tool/tissue interactions (types and transitions) performed in laparoscopic surgery are skill-dependent, and (2) statistical models (Hidden Markov Models--HMMs) incorporating these data are capable of objectively evaluating laparoscopic surgical skills. MATERIALS AND METHODS: Eight subjects (six residents--two first-year (R1), two third-year (R3), and two fifth-year (R5)--and two expert laparoscopic surgeons) performed laparoscopic cholecystectomy on pigs using an instrumented grasper equipped with force/torque (F/T) sensors at the hand/tool interface, and F/T data was synchronized with video of the operative maneuvers. Fourteen types of tool/tissue (T/T) interactions, each associated with unique F/T signatures, were defined from frame-by-frame video analysis. HMMs for each subject and step of the operation were compared to evaluate the statistical distance between expert surgeons and residents with different skill levels. RESULTS: The statistical distances between HMMs representing expert surgeons and residents were significantly different (alpha < 0.05). Major differences occurred in: (1) F/T magnitudes; (2) type of T/T interactions and transitions between them; and (3) time intervals for each T/T interaction and overall completion time. The greatest difference in performance was between R1 (junior trainee) and R3 (midlevel trainee). Smaller changes were seen as expertise increased beyond the R3 level. CONCLUSION: HMMs incorporating haptic and visual information provide an objective tool for evaluating surgical skills. Objective evidence for a "learning curve" suggests that surgical residents acquire a major portion of their laparoscopic skill between year 1 and year 3 of training.
Animals↗
Computer-controlled motorized endoscopic grasper for in vivo measurement of soft tissue biomechanical characteristics.
Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic devices. Surgical simulation technology has progressed rapidly but without a large database of soft tissue mechanical properties with which to incorporate. The device described here is a computer-controlled, motorized endoscopic grasper capable of applying surgically relevant levels of force to tissue in vivo and measuring the tissue's force-deformation properties.
Abdomen↗
The Blue DRAGON--a system for monitoring the kinematics and the dynamics of endoscopic tools in minimally invasive surgery for objective laparoscopic skill assessment.
Minimally invasive surgeiy (MIS) involves a multi-dimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in mastering MIS surgery but may also be used to define objective criteria for characterizing surgical performance. The BIueDRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools along with the visual view of the surgical scene. It includes two four-bar mechanisms equipped with position and force torque sensors for measuring the positions and the orientations (P/O) of two endoscopic tools along with the forces and torques applied by the surgeons hands. The methodology of decomposing the surgical task is based on a fully connected, finite-states (28 states) Markov model where each states corresponded to a fundamental tool/tissue interaction based on the tool kinematics and associated with unique F/T signatures. The experimental protocol included seven MIS tasks performed on an animal model (pig) by 30 surgeons at different levels of their residency training. Preliminary analysis of these data showed that major differences between residents at different skill levels were: (i) the types of tool/tissue interactions being used, (ii) the transitions between tool/tissue interactions being applied by each hand, (iii) time spent while perfonning each tool/tissue interaction, (iv) the overall completion time, and (v) the variable F/T magnitudes being applied by the subjects through the endoscopic tools. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and the dynamics of the surgical tool may benefit from inclusion of the proposed methodology for analysis of efficacy and objective evaluation of surgical skills during training.
Animals↗