Safety and efficacy of Symani robotic-assisted microsurgery: Assessment of vascular anastomosis patency, thrombus, and stenosis in a randomized preclinical study.

INTRODUCTION: The Symani surgical system undergoes scrutiny in this study as part of a series of preclinical investigations. Previous studies compared the precision of robotic-assisted anastomoses with manual techniques. This study aimed to evaluate the critical, histological, and gross parameters at the site of anastomosis and at distant sites in a rat model to provide insights into the safety and efficacy of robotic-assisted microsurgery to enhance its potential for clinical adoption. MATERIALS AND METHODS: Experienced microsurgeons performed arterial and venous anastomoses in 16 Wistar rats, randomized into four treatment groups: robotic artery, robotic vein, manual artery, and manual vein. Various parameters were evaluated at two time points (T0 and T30) on the day of the procedure and at Day 28 (T28d). In the second phase of the study, the animals underwent necropsy, histopathologic analysis, micro-CT scans, and angiography imaging of the anastomosis sites, major organs, and distant target organs by a blinded assessor. RESULTS: Patency rates were 100% at T0 and T30 for all anastomoses and stayed at 100% on T28d for the robotic subgroups; however, it decreased to 87.5% for manual arterial anastomoses owing to a case of obstructive thrombus. No evidence of clot migration was observed. Blood flow parameters and procedure times did not differ significantly. The blinded semiquantitative histological analysis revealed no significant disparities between the robotic and manual anastomoses across various pathological indicators. No gross abnormalities were detected in musculoskeletal examinations. CONCLUSION: This preclinical study demonstrated the safety of the Symani surgical system. Results suggest equivalence between robotic and manual techniques regarding thrombus formation at the anastomotic site and distal organs.

Robotic-Assisted Anastomosis in Orthoplastic Surgery: Preliminary Data.

BACKGROUND: The evolution of microsurgery has relied on advancements in operating microscopes and surgical instruments. Pioneering advancements, however, especially within the domain of "super-microsurgery", challenge the limits of human dexterity by dealing with anastomoses between vessels smaller than 0.8 mm. Based on these premises, the Symani robotic system was designed and developed. This platform utilizes teleoperation and motion-scaled movement to provide surgeons with precision and accuracy in manipulating millimetre and submillimetre-sized anatomical structures. In this study, we present our experience in performing robotic-assisted anastomoses using the Symani Surgical System in free flap reconstruction. METHODS: We present a comprehensive analysis of all reconstructive procedures involving microsurgical free flaps performed using the Symani robotic platform at the orthoplastic unit of the Rizzoli Orthopaedic Institute from 1 October 2022 to 1 May 2023. RESULTS: Sixteen microsurgical reconstructions using free flaps were performed, involving a total of 40 anastomoses on vessel calibres ranging from 0.6 mm to 2.5 mm. In each case, the anastomosis was executed with the assistance of the robotic platform, achieving a 100+% success rate in patent anastomoses, and no major complications occurred.Conclusion The Symani system has proven to be safe and reliable in performing microsurgical anastomoses. While this platform demonstrated successful in various vessel calibres, its most promising potential lies in anastomoses below the size of a millimetre. Larger patient cohorts and extended investigation periods will be essential to explore whether robotics in microsurgery offers advantages across all microsurgical procedures or should be reserved for selected cases.

A chimeric medial femoral condyle chondro-osseus flap with two thin periosteal flaps to reconstruct partial necrosis of talar body: A case report.

Total talar extrusion is a rare complication of high-energy traumas. A consequence of this injury can be avascular necrosis (AVN) of the talus. Patients are confronted with pain, limited range of motion and post-traumatic arthritis. As AVN progresses the talus is gradually destroyed. This report presents the use of a chimeric medial femoral condyle chondro-osseus flap with two thin periosteal flaps to increase vascular supply to the traumatized area, accelerate bone formation, flap integration, and restore articular surfaces in a patient with partial necrosis of talar body. The patient was a 26-year-old female with open left lateral talar extrusion after a motor-vehicle accident that developed a partial avascular necrosis, at the level of the subtalar and ankle joint with altered talar dome surface with partial depression of 2 cm. The patient was in pain and not able to walk. The medial femoral condyle chondro-osseus portion was placed in the talar dome depression to restore the subtalar joint, the periosteal flaps were placed on top to reconstruct the ankle joint restoring the articular surfaces and the correct weight-bearing distribution. No complications or morbidity of donor site were observed. One year after the operation, the patient walks free, without pain. Post-operatory x-ray performed, evidenced progressive bone healing and reduction of the AVN. In the intent of performing a joint-saving procedure, the presented chimeric flap might be effective in the short-term with excellent clinical and radiographic outcomes.

Gender dysphoria: Quality of online information for gender reassignment surgery.

An ever-increasing number of patients are using the Internet to learn about medical conditions. This study aimed to evaluate the quality of Internet-based patient information on gender reassignment surgery for people who suffer from gender dysphoria. Twenty websites identified using Google and Yahoo search engines were selected and evaluated based on the modified Ensuring Quality Information for Patients (EQIP) instrument (36 items). The EQIP tool comprises 36 questions to which the answer can be "yes" or "no". The final score for each website can be between 0 and 36. An overall score of 26 or above was considered high, because it co-related to the 72nd percentile. The average of the scores turned out to be 22.5 points, lower than our target; 7 (35%) sites were rated higher than the average and 13 (65%) were rated lower. The assessment of the websites included in the study showed a lack of information about the sequence of the medical procedures, perioperative criticalities and qualitative risks and side-effects descriptions. The overall quality of published information on gender reassignment surgery is very low. We believe that the Internet should not be used as the main source of medical information, and physicians should maintain the leadership in guiding patients affected by gender dysphoria. Level of Evidence: Level IV, case study.

Current fluctuations in stochastically resetting particle systems.

We consider a system of noninteracting particles on a line with initial positions distributed uniformly with density ρ on the negative half-line. We consider two different models: (i) Each particle performs independent Brownian motion with stochastic resetting to its initial position with rate r and (ii) each particle performs run-and-tumble motion, and with rate r its position gets reset to its initial value and simultaneously its velocity gets randomized. We study the effects of resetting on the distribution P(Q,t) of the integrated particle current Q up to time t through the origin (from left to right). We study both the annealed and the quenched current distributions and in both cases, we find that resetting induces a stationary limiting distribution of the current at long times. However, we show that the approach to the stationary state of the current distribution in the annealed and the quenched cases are drastically different for both models. In the annealed case, the whole distribution P_{an}(Q,t) approaches its stationary limit uniformly for all Q. In contrast, the quenched distribution P_{qu}(Q,t) attains its stationary form for QQ_{crit}(t). We show that Q_{crit}(t) increases linearly with t for large t. On the scale where Q∼Q_{crit}(t), we show that P_{qu}(Q,t) has an unusual large deviation form with a rate function that has a third-order phase transition at the critical point. We have computed the associated rate functions analytically for both models. Using an importance sampling method that allows to probe probabilities as tiny as 10^{-14000}, we were able to compute numerically this nonanalytic rate function for the resetting Brownian dynamics and found excellent agreement with our analytical prediction.

Cost of Diffusion: Nonlinearity and Giant Fluctuations.

We introduce a simple model of diffusive jump process where a fee is charged for each jump. The nonlinear cost function is such that slow jumps incur a flat fee, while for fast jumps the cost is proportional to the velocity of the jump. The model-inspired by the way taxi meters work-exhibits a very rich behavior. The cost for trajectories of equal length and equal duration exhibits giant fluctuations at a critical value of the scaled distance traveled. Furthermore, the full distribution of the cost until the target is reached exhibits an interesting "freezing" transition in the large-deviation regime. All the analytical results are corroborated by numerical simulations. Our results also apply to elastic systems near the depinning transition, when driven by a random force.

CT Perfusion as a Predictor of the Final Infarct Volume in Patients with Tandem Occlusion.

BACKGROUND: CT perfusion (CTP) is used in patients with anterior circulation acute ischemic stroke (AIS) for predicting the final infarct volume (FIV). Tandem occlusion (TO), involving both intracranial large vessels and the ipsilateral cervical internal carotid artery could generate hemodynamic changes altering perfusion parameters. Our aim is to evaluate the accuracy of CTP in the prediction of the FIV in TOs. METHODS: consecutive patients with AIS due to middle cerebral artery occlusion, referred to a tertiary stroke center between March 2019 and January 2021, with an automated CTP and successful recanalization (mTICI = 2b - 3) after endovascular treatment were retrospectively included in the tandem group (TG) or in the control group (CG). Patients with parenchymal hematoma type 2, according to ECASS II classification of hemorrhagic transformations, were excluded in a secondary analysis. Demographic, clinical, radiological, time intervals, safety, and outcome measures were collected. RESULTS: among 319 patients analyzed, a comparison between the TG (N = 22) and CG (n = 37) revealed similar cerebral blood flow (CBF) > 30% (29.50 ± 32.33 vs. 15.76 ± 20.93 p = 0.18) and FIV (54.67 ± 65.73 vs. 55.14 ± 64.64 p = 0.875). Predicted ischemic core (PIC) and FIV correlated in both TG (tau = 0.761, p < 0.001) and CG (tau = 0.315, p = 0.029). The Bland-Altmann plot showed agreement between PIC and FIV for both groups, mainly in the secondary analysis. CONCLUSION: automated CTP could represent a good predictor of FIV in patients with AIS due to TO.

Soft Tissue Reconstruction of the Posterior Trunk after Tumor Excision: A Surgical Algorithm.

BACKGROUND: The posterior trunk has been considered a challenging area to reconstruct following soft tissue tumor excision because of the shortage of local donor sites. The advent of innovative procedures such as perforator flaps has radically changed this perspective and offered a new approach to the problem. METHODS: Upon a review of the literature and the personal experiences of the senior author, an algorithm is developed according to the most updated procedure, combined with more conventional options that maintain a role in decision-making. RESULTS: The upper back latissimus dorsi and trapezium flap are still the most reliable approaches, while perforator flaps based either on the circumflex scapular arteries or the transverse cervical artery represent a more refined option. In the middle third, few indications remain for the reverse latissimus dorsi, while the gold standard is represented by local perforator flaps based on the posterior intercostal system. In the lower back, conventional VY advancement flaps are still a safe and effective option in the sacral area, and perforator flaps based on posterior intercostal arteries, lumbar arteries and superior gluteal arteries are the first choice in most cases. CONCLUSIONS: Using perforator flaps significantly improved soft tissue reconstruction in the posterior trunk.

Viscoelastic confinement induces periodic flow reversals in active nematics.

We use linear stability analysis and hybrid lattice Boltzmann simulations to study the dynamical behavior of an active nematic confined in a channel made of viscoelastic material. We find that the quiescent, ordered active nematic is unstable above a critical activity. The transition is to a steady flow state for high elasticity of the channel surroundings. However, below a threshold elastic modulus, the system produces spontaneous oscillations with periodic flow reversals. We provide a phase diagram that highlights the region where time-periodic oscillations are observed and explain how they are produced by the interplay of activity and viscoelasticity. Our results suggest experiments to study the role of viscoelastic confinement in the spatiotemporal organization and control of active matter.