In-Vivo and Postmortem Compressive Properties of Porcine Abdominal Organs In-Vivo and Postmortem Compressive Properties of Porcine Abdominal Organs

Abstract. In order to provide realistic haptic feedback, simulators must incorporate accurate computational models of the in-vivo mechanical behavior of soft tissues. Surgical simulation technology has progressed rapidly but lacks a comprehensive database of soft tissue mechanical properties with which to incorporate. Simulators are often designed purely based on what "feels about right;" quantitative empirical data are lacking. It is important to test tissues in-vivo and apply surgically relevant ranges of force, deformation, and duration. A motorized endoscopic grasper was used to test seven porcine abdominal organs invivo, in-situ, and ex-corpus with cyclic and static compressive loadings. Elastic and stress relaxation characteristics were examined. Results from liver are presented here. Notable differences were found between successive squeezes and between conditions for elastic and relaxation behaviors.

Outcomes and Quality of Life Among Men After Anal Sphincter-Sparing Transperineal Rectourethral Fistula Repair.

ObjectiveTo describe long-term quality of life (QOL) outcomes after rectourethral fistula (RUF) repair. RUF is a debilitating diagnosis and complex surgical dilemma with limited data regarding QOL after repair.MethodsPatients at a tertiary referral center undergoing transperineal RUF repair 1/2009-5/2016 were analyzed. Patients were contacted by telephone to assess QOL following repair. Descriptive analysis performed of short-term surgical data (success and complications) and long-term QOL data (novel questionnaire).ResultsTwenty one men underwent RUF surgery with 95% success after initial repair. Fifty two percent had a history of radiation and/or ablation. Four individuals (19%) experienced a Clavien-Dindo complication within 30 days, with 3 of those being grade III+. Fifteen had postoperative urinary incontinence, of whom 73% underwent artificial urinary sphincter placement. Three previously radiated individuals underwent subsequent urethral stricture surgery. At long-term follow-up (mean 45.6 ± 27.1 months), 53% reported perineal pain, 43% reported problems related to the gracilis flap, and 80% reported urinary incontinence (primarily occasional mild leakage). Twenty one percent were unable to do the things they wanted in their daily lives, while 80% reported that surgery positively impacted their life. None would have opted for complete urinary diversion.ConclusionRUF repair leads to patient satisfaction and improved QOL, despite possible residual issues such as perineal pain and urinary incontinence. Definitive RUF repair should be offered to suitable radiated and nonradiated patients

Kinematic optimization of a spherical mechanism for a minimally invasive surgical robot

Abstract—With a focus on design methodology for developing a compact and lightweight minimally invasive surgery (MIS) robot manipulator, the goal of this study is progress toward a next-generation surgical robot system that will help surgeons deliver healthcare more effectively. Based on an extensive database of in-vivo surgical measurements, the workspace requirements were clearly defined. The pivot point constraint in MIS makes the spherical manipulator a natural candidate. An experimental evaluation process helped to more clearly understand the application and limitations of the spherical mechanism as an MIS robot manipulator. The best configuration consists of two serial manipulators in order to avoid collision problems. A complete kinematic analysis and optimization incorporating the requirements for MIS was performed to find the optimal link lengths of the manipulator. The results show that for the serial spherical 2-link manipulator used to guide the surgical tool, the optimal link lengths (angles) are (60,50). A prototype 6-DOF surgical robot has been developed and will be the subject of further study. Index Terms—Isotropy, Jacobian, minimally invasive surgery, optimization, serial mechanism, spherical mechanism, surgical robot

Outcomes and Quality of Life Among Men After Anal Sphincter-Sparing Transperineal Rectourethral Fistula Repair.

ObjectiveTo describe long-term quality of life (QOL) outcomes after rectourethral fistula (RUF) repair. RUF is a debilitating diagnosis and complex surgical dilemma with limited data regarding QOL after repair.MethodsPatients at a tertiary referral center undergoing transperineal RUF repair 1/2009-5/2016 were analyzed. Patients were contacted by telephone to assess QOL following repair. Descriptive analysis performed of short-term surgical data (success and complications) and long-term QOL data (novel questionnaire).ResultsTwenty one men underwent RUF surgery with 95% success after initial repair. Fifty two percent had a history of radiation and/or ablation. Four individuals (19%) experienced a Clavien-Dindo complication within 30 days, with 3 of those being grade III+. Fifteen had postoperative urinary incontinence, of whom 73% underwent artificial urinary sphincter placement. Three previously radiated individuals underwent subsequent urethral stricture surgery. At long-term follow-up (mean 45.6 ± 27.1 months), 53% reported perineal pain, 43% reported problems related to the gracilis flap, and 80% reported urinary incontinence (primarily occasional mild leakage). Twenty one percent were unable to do the things they wanted in their daily lives, while 80% reported that surgery positively impacted their life. None would have opted for complete urinary diversion.ConclusionRUF repair leads to patient satisfaction and improved QOL, despite possible residual issues such as perineal pain and urinary incontinence. Definitive RUF repair should be offered to suitable radiated and nonradiated patients

Generalized approach for modeling minimally invasive surgery as a stochastic process using a discrete markov model

Abstract—Minimally invasive surgery (MIS) involves a multidimensional 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 defining objective criteria for characterizing surgical performance. The Blue DRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools synchronized with the endoscopic view of the surgical scene. Modeling the process of MIS using a finite state model [Markov model (MM)] reveals the internal structure of the surgical task and is utilized as one of the key steps in objectively assessing surgical performance. The experimental protocol includes tying an intracorporeal knot in a MIS setup performed on an animal model (pig) by 30 surgeons at different levels of training including expert surgeons. 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 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 in which the kinematics and the dynamics of the surgical tool are inherently measured may benefit from incorporation of the proposed methodology. Index Terms—Dynamics, haptics, human machine interface, kinematics, manipulation, Markov model, minimally invasive, robotics, simulation, soft tissue, surgery, surgical skill assessment, surgical tool, vector quantization. I

Effect of Time Delay on TeleSurgical Performance

Abstract — In the area of surgical robotics no standard means of performance evaluation has been established. Thousands of surgeons have gone through the SAGES FLS Program, and the psychomotor skill portion of the program is considered the gold standard in laparoscopic skills evaluation. This research describes the use of the FLS Block Transfer task to evaluate the performance of both surgeons and non-surgeons teleoperating under different time delay conditions on the University of Washington RAVEN Surgical Robot. Time delays of 0ms, 250ms, and 500ms were used and a statistically significant difference in mean block transfer time as well as mean tool tip path length were shown. For this task no significant difference was shown between the surgeon and non-surgeon groups. Clearly surgeon input and feedback is key to surgical robotic system development, but this result implies that non-surgeon subjects can be tested for simple usability evaluations. I

An Instrumented Minimally Invasive Surgical Tool: Design and Calibration

Minimally invasive surgical procedures have improved the standard of patient care by reducing recovery time, chance of infection, and scarring. A recent review estimates that leaks occur in 3% to 6% of bowel anastomoses, resulting in “increased morbidity and mortality and adversely [affecting] length of stay, cost, and cancer recurrence” [23]. Many of these leaks are caused by poor handling and ischemic tissue