Heat conduction in live tissue during radiofrequency electrosurgery.

In this paper, we propose a method to model radiofrequency electrosurgery to capture the phenomena at higher temperatures and present the methods for parameter estimation. Experimental data taken from our surgical trials performed on in vivo porcine liver show that a non-Fourier Maxwell-Cattaneo-type model can be suitable for this application when used in combination with an Arrhenius-type model that approximates the energy dissipation in physical and chemical reactions. The resulting model structure has the advantage of higher accuracy than existing ones, while reducing the computation time required.

Minimally Invasive Live Tissue High-fidelity Thermophysical Modeling using Real-time Thermography.

We present a novel thermodynamic parameter estimation framework for energy-based surgery on live tissue, with direct applications to tissue characterization during electrosurgery. This framework addresses the problem of estimating tissue-specific thermodynamics in real-time, which would enable accurate prediction of thermal damage impact to the tissue and damage-conscious planning of electrosurgical procedures. Our approach provides basic thermodynamic information such as thermal diffusivity, and also allows for obtaining the thermal relaxation time and a model of the heat source, yielding in real-time a controlled hyperbolic thermodynamics model. The latter accounts for the finite thermal propagation time necessary for modeling of the electrosurgical action, in which the probe motion speed often surpasses the speed of thermal propagation in the tissue operated on. Our approach relies solely on thermographer feedback and a knowledge of the power level and position of the electrosurgical pencil, imposing only very minor adjustments to normal electrosurgery to obtain a high-fidelity model of the tissue-probe interaction. Our method is minimally invasive and can be performed in situ. We apply our method first to simulated data based on porcine muscle tissue to verify its accuracy and then to in vivo liver tissue, and compare the results with those from the literature. This comparison shows that parameterizing the Maxwell-Cattaneo model through the framework proposed yields a noticeably higher fidelity real-time adaptable representation of the thermodynamic tissue response to the electrosurgical impact than currently available. A discussion on the differences between the live and the dead tissue thermodynamics is also provided.

Development of an affordable, immersive model for robotic vaginal cuff closure: a randomized trial.

Safe and secure closure of the vaginal cuff is a critical component of a robotic assisted hysterectomy procedure. Our aim in this study is to develop and validate a novel vaginal cuff closure model (VC) created from porcine heart that allows trainees to obtain competency in a low-risk environment. Ten expert and 20 novice robotic surgeons performed a cuff closure exercise on the VC model and on the dV-Trainer®, a virtual reality simulator (VR). Performances were timed, videotaped, and scored using the modified Global Evaluative Assessment of Robotic Skills (mGEARS) score. Expert robotic surgeons completed the task faster on both the VR (531 vs. 814 s, p = 0.03) and the VC platforms (311 vs. 631 s, p < 0.001) and achieved higher mGEAR scores (32.25 vs. 22.07, p < 0.0001). Knot quality and suturing accuracy were better in the VC than in the VR environment in both groups. In a post-completion survey, both expert and novice surgeons expressed strong preference towards the VC model. In this study, the novel VC model proved to be a reliable simulation tool with high face, content, and construct validity. Due to its simplicity and low cost, this high-yield simulation exercise can easily be incorporated into robotic training curricula of obstetrics and gynecology residents.

Robotic-Assisted Roux-en-Y Gastric Bypass: Learning Curve Assessment Using Cumulative Sum and Literature Review.

Purpose: Robotic-assisted Roux-en-Y gastric bypass (RARYGB) is a procedure that is used with increasing frequency in the United States. Among other bariatric procedures, RARYGB is a good model for the robotic platform because it allows hand-sewn suturing and energy devices application. The aim of this study was to conduct a literature review of robotic approach in RARYGB, its learning curve using the cumulative sum (CUSUM) method, and our experience as Center of Excellence recognized by the American Society for Metabolic and Bariatric Surgery (ASMBS). Methods: A total of 67 patients were included. Results revealed that the learning curve was achieved after case 11. Eighteen studies were included in the pooled analysis. Results: An increase in the operative time was noted at case 46, in which a second phase was identified. A significant difference between these two phases was found only related to previous bariatric surgery. The outcomes of this series were comparable with the ones available in the literature. Conclusions: The robotic platform is increasing its role in complex procedures such as RARYGB. The hand-sewn technique may offer important advantages in terms of shorter learning curve, reduced conversion rate, and lower leakage rate.

Robot-Assisted Revisional Surgery of Gastric Greater Curvature Plication to Roux-en-Y Gastric Bypass.

Laparoscopic gastric greater curvature plication (LGGCP) has been presented as an alternative to laparoscopic sleeve gastrectomy (LSG) for reversible reduction of stomach capacity without gastric reduction or stapling. We present a case of a 51-year-old Hispanic female with a BMI of 41.91 kg/m2, who underwent (LGGCP) 5 years previously at another institution. Despite multiple interventions, the patient was unable to successfully lose weight, and the decision was made to reverse the procedure with a robot-assisted Roux-en-Y gastric bypass. The plication was intact extending from the fundus to the antrum, with the sutures incorporated by scarring and fibrotic tissue. Sutures were delicately removed to form a 30-cc pouch, followed by jejuno-jejunal and gastrojejunal anastomosis. The patient tolerated the surgery well and control fluoroscopy was negative for anastomotic leaks, patient was discharged home on POD 2. At the 40-day follow-up, the patient had lost 22 lb., reducing her BMI to 37.64 kg/m2. The 3D vision of the robotic camera and the six degrees of freedom of the robotic instruments seemed to facilitate the challenging dissection of the embedded sutures used for the LGGCP and its overall undoing. However, further volume and data on the robotic approach for this specific revisional procedure are necessary before drawing any definitive conclusions.