Search Results (13)

Background: Endovascular treatment has become the major choice for treating intracranial aneurysm (IA). The development of novel endovascular devices for IA treatment is, therefore, socially important. For this purpose, a preclinical animal model to test a prototype of devices plays a crucial role. The major problems regarding currently used preclinical animal models, mainly in medium-to-large animals, are the expense and the lack of IA pathology, as they only mimic the morphological aspect. Methods: Sprague–Dawley rats were used, and the new bifurcation was formed via end-to-side anastomosis of carotid arteries. An aneurysm lesion induced at the newly formed bifurcation site was macroscopically assessed. Endovascular coiling of the induced aneurysm was then done. Results: An aneurysm lesion with a balloon-like shape, as in human cases, was induced at the newly formed bifurcation site. Some of the induced lesions spontaneously ruptured. Endovascular coiling was successfully done by using the micro-catheter and coil used at the clinical site. Conclusions: The rat model of IAs established here provides a novel platform contributing to the development of endovascular devices to treat IAs and, therefore, significantly facilitates the development of devices to achieve more effective treatment. Full article

Chronic liver disease remains a leading cause of global mortality, yet organ shortages and transplant complications limit the efficacy of orthotopic liver transplantation. While extracorporeal support systems serve as temporary bridges, they fail to restore long-term patient autonomy or replicate complex biosynthetic functions. This systematic review, conducted in accordance with PRISMA 2020 guidelines, evaluates recent advancements in implantable artificial livers (IALs) designed for permanent functional integration. We analyzed 71 eligible studies, assessing cellular sources, fabrication strategies, maturation processes, and functional readiness. Our findings indicate significant progress in stem-cell-derived hepatocytes and bioactive scaffolds, such as decellularized extracellular matrix (dECM). However, a critical technological gap remains in scaling current sub-centimeter prototypes toward clinically relevant volumes (~200 mL). Key engineering challenges include integrating hierarchical vascular networks, requiring primary vessels exceeding 2 mm in diameter for surgical anastomosis, and functional biliary systems to prevent cholestatic injury. Furthermore, while micro-vascularization and protein synthesis are well documented, higher-order functions such as spatial zonation and coordinated metabolic stability remain underreported. Future clinical translation necessitates advancements in multi-cellular patterning, microfluidic-driven maturation, and autologous reprogramming. This review provides a comprehensive roadmap for bridging the gap between biofabricated constructs and organ-scale hepatic replacement, emphasizing the need for standardized functional benchmarks to ensure long-term success. Full article

Background and Objectives: In coronary artery bypass grafting (CABG) on pump, achieving optimal visualization is critical for surgical precision and safety. The use of blowers to clear the CABG anastomosis poses risks, including the formation of micro-embolic gas bubbles, which can be insidious and increase the risk of cerebral or myocardial complications. This retrospective study compares the effectiveness of the use of irrigation mist and CO₂ versus a direct CO₂ blower without irrigation in terms of visualization, postoperative fibrillation, and micro-embolic gas activity. Materials and Methods: The study involved 40 patients who underwent on-pump CABG, with 20 patients assigned to the irrigation mist and CO₂ group (ClearView™) and 20 to the direct CO₂ blower group. Primary outcomes included the quality of intraoperative visualization, the incidence of fibrillation at aortic de-clamping, and the presence of micro-embolic gas activity detected via transesophageal echocardiography (TEE) in the cardiac chambers. Results: Patients in the irrigation mist and CO₂ group experienced superior visualization and reduced tissue desiccation. Fibrillation at the time of aortic de-clamping occurred in two patients (10%) using the irrigation mist and CO₂, compared to eight patients (40%) using the direct CO₂ blower. Additionally, TEE monitoring revealed lower levels of micro-embolic gas activity in the irrigation mist and CO₂ group, indicating a potential reduction in gas embolization risk. Conclusions: The irrigation mist and CO₂ system not only provides enhanced visualization during CABG but also significantly reduces the incidence of fibrillation during aortic de-clamping and micro-embolic gas activity. These findings suggest improved patient safety and outcomes, highlighting the irrigation mist and CO₂ system as a potentially safer alternative to direct CO₂ blowing in the context of myocardial revascularization. Full article

Background/Objectives: Robotic-assisted surgery has revolutionised modern medicine, enabling greater precision and control, particularly in microsurgical procedures. This systematic review evaluates the current state of robotic-assisted surgery across various specialties, focusing on four major robotic systems: Symani, Da Vinci, ZEUS, and MUSA. Methods: The review systematically analyses the effectiveness of these systems in performing vascular, lymphatic, and nervous anastomoses, comparing key metrics such as procedure time, success rates, and learning curves against manual techniques. It includes 48 studies, highlighting the technological capabilities and limitations of these systems in direct comparisons. Results: Results indicate that while robotic procedures often take longer than manual methods, significant improvements in efficiency are observed as surgeons gain experience. Conclusions: Overall, this study provides insights into the future potential of robotic-assisted surgery and highlights areas that require further research. It ultimately aims to promote the application of robotic systems in cranial neurosurgery, with a particular focus on advancing neurovascular techniques, such as microsuturing for bypass procedures. Full article

Complex microvascular techniques and in-depth knowledge of blood rheology and microanastomosis function are required for success in microvascular flap surgery. Substantial progress has been achieved in preventing complications, but the rate of flap loss is still significant and can have significant adverse effects on the patient. Flap thrombosis, flap hematoma, and flap loss are the most frequent and severe major surgical complications. Advances in understanding the pathophysiology of different flap complications, the use of preoperative risk assessment and new treatment concepts could improve the perioperative care of microvascular flap surgery patients. Our aim was to outline novel avenues for best practice and provide an outlook for further research of anesthesia and perioperative care concepts in microvascular flap surgery. Full article

Background: The literature lacks a combined analysis of neurosurgical microvascular anastomosis training models. We performed a systematic literature search to provide an overview of the existing models and proposed a classification system based on the level of simulation and reproducibility of the microvascular anastomosis. Methods: The systematic literature search followed the PRISMA guidelines. We consulted MEDLINE, Web of Knowledge, and EMBASE independently for papers about bypass training models. Every training model was analyzed according to six tasks supposed to esteem their fidelity to the real operative setting by using a scoring system from zero to two. Finally, authors classified the models into five classes, from A to E, by summing the individual scores. Results: This study included 109 papers for analysis. Training models were grouped into synthetic tubes, ex vivo models (animal vessels, fresh human cadavers, human placentas) and in vivo simulators (live animals—rats, rabbits, pigs). By applying the proposed classification system, live animals and placentas obtained the highest scores, falling into class A (excellent simulators). Human cadavers and animal vessels (ex vivo) were categorized in class B (good simulators), followed by synthetic tubes (class C, reasonable simulators). Conclusions: The proposed classification system helps the neurosurgeon to analyze the available training models for microvascular anastomosis critically, and to choose the most appropriate one according to the skills they need to improve Full article

Hemorheological factors may show arterio-venous differences. Alterations in acid-base and metabolic parameters may also influence these factors. However, little is known about changes in micro-rheological parameters during abdominal surgery, influencing splanchnic circulation. In anesthetized pigs, the external jugular vein, femoral artery and vein were cannulated unilaterally, and paramedian laparotomy was performed. In the anastomosis group, after resecting a bowel segment, end-to-end jejuno-jejunostomy was completed. Blood samples (from cannulas and by puncturing the portal vein) were taken before and after the intervention. Hematological, acid-base and blood gas parameters, metabolites, red blood cell (RBC) deformability and aggregation were determined. The highest hematocrit was found in portal blood, increasing further by the end of operation. A significant pH decrease was seen, and portal blood showed the highest lactate and creatinine concentration. The highest RBC aggregation values were found in arterial, the lowest in renal venous blood. The RBC aggregation increased with higher lactate concentration and lower pH. Osmotic gradient deformability declined, with the lowest values in portal and renal venous samples. In conclusion, micro-rheological parameters showed arterio-venous and porto-renal venous differences, influenced by oxygenation level, pH and lactate concentration. The intestinal anastomosis operation caused an immediate micro-rheological deterioration with portal venous dominancy in this experiment. Full article

Background: In recent years, three-dimensional exoscopes have been increasingly applied in neurosurgery. Multiple exoscopic systems are available, all offering specific features. In this study, we assessed practical and visualization performance of four different exoscopic systems in a highly challenging microsurgical procedure, and evaluated whether these affected the quality of work. Methods: We included four different exoscopes: Olympus ORBEYE, Zeiss KINEVO, Storz VITOM, and Aesculap AEOS. With each exoscope, ten experimental bypass procedures were carried out on chicken wing vessels at a depth of 3 cm. We evaluated the quality of the anastomoses, the practical considerations for the setup of the exoscopic systems, and the visualization quality by tracking the number of unnecessary movements. Results: All included exoscopes enabled us to perform the bypass procedures with mostly adequate or excellent results. Surgically, the most pronounced difference between the exoscopes was the duration of the procedure, which was mainly due to the number of unnecessary movements. Practically, the exoscopes differ highly which is important when considering which exoscope to apply. Conclusions: This is the first study comparing different exoscope systems while performing the same challenging microsurgical procedure. We found major practical differences between the exoscopes that determine the suitability of an exoscope based on the demands and conditions of the surgical procedure. Therefore, preprocedural practical training with the exoscope is required. Full article

Introduction: This study compares the intraoperative process of hepatic artery anastomosis using conventional microscope and novel 3D digital microscope and discusses our technique and operative set-up. Method: A retrospective comparative cohort study with 46 hepatic artery reconstructions in living donor liver transplant patients. Either an operational microscope (control group) or a 3D digital microscope Mitaka Kestrel View II (study group) was used for hepatic artery anastomosis. We then discuss and share our institution’s experience of improving surgical training. Results: Both operation instruments provide effective and comparable results. There was no statistical difference regarding operational objective results between conventional microscope and exoscope. Both instruments have no hepatic artery size limit, and both resulted in complete vessel patency rate. Conclusions: There was no statistical differences regarding hepatic artery anastomosis between microscope and exoscope cohorts. Microsurgeons should perform hepatic artery anastomosis efficiently with the instruments they are most proficient with. Yet, exoscope provided better ergonomics in the operation room and lessened musculoskeletal strain, allowing surgeons to work in a more neutral and comfortable posture while allowing the first assistant to learn and assist more effectively. Using exoscope with micro-forceps and modified tie technique make artery reconstruction easier. Full article

We present a multi-scale mathematical model and a novel numerical solver to study blood plasma flow and oxygen concentration in a prototype model of an implantable Bioartificial Pancreas (iBAP) that operates under arteriovenous pressure differential without the need for immunosuppressive therapy. The iBAP design consists of a poroelastic cell scaffold containing the healthy transplanted cells, encapsulated between two semi-permeable nano-pore size membranes to prevent the patient’s own immune cells from attacking the transplant. The device is connected to the patient’s vascular system via an anastomosis graft bringing oxygen and nutrients to the transplanted cells of which oxygen is the limiting factor for long-term viability. Mathematically, we propose a (nolinear) fluid–poroelastic structure interaction model to describe the flow of blood plasma through the scaffold containing the cells, and a set of (nonlinear) advection–reaction–diffusion equations defined on moving domains to study oxygen supply to the cells. These macro-scale models are solved using finite element method based solvers. One of the novelties of this work is the design of a novel second-order accurate fluid–poroelastic structure interaction solver, for which we prove that it is unconditionally stable. At the micro/nano-scale, Smoothed Particle Hydrodynamics (SPH) simulations are used to capture the micro/nano-structure (architecture) of cell scaffolds and obtain macro-scale parameters, such as hydraulic conductivity/permeability, from the micro-scale scaffold-specific architecture. To avoid expensive micro-scale simulations based on SPH simulations for every new scaffold architecture, we use Encoder–Decoder Convolution Neural Networks. Based on our numerical simulations, we propose improvements in the current prototype design. For example, we show that highly elastic scaffolds have a higher capacity for oxygen transfer, which is an important finding considering that scaffold elasticity can be controlled during their fabrication, and that elastic scaffolds improve cell viability. The mathematical and computational approaches developed in this work provide a benchmark tool for computational analysis of not only iBAP, but also, more generally, of cell encapsulation strategies used in the design of devices for cell therapy and bio-artificial organs. Full article

While surgical options exist to treat lymphedema after axillary lymph node dissection (ALND), the lymphatic microsurgical preventive healing approach (LYMPHA) has been introduced as a preventive measure performed during the primary surgery, thus avoiding the morbidity associated with lymphedema. Here, we highlight details of our operative technique and review postoperative outcomes. For our patients, limb measurements and body composition analyses were performed pre- and postoperatively. Intraoperatively, axillary reverse lymphatic mapping was performed with indocyanine green (ICG) and lymphazurin. SPY-PHI imaging was used to visualize the ICG uptake into axillary lymphatics. Cut lymphatics from excised nodes were preserved for lymphaticovenous anastomosis (LVA). At the completion of the microanastomosis, ICG was visualized draining from the lymphatic through the recipient vein. A retrospective review identified nineteen patients who underwent complete or partial mastectomy with ALND and subsequent LYMPHA over 19 months. The number of LVAs performed per patient ranged between 1–4 per axilla. The operating time ranged from 32–95 min. There were no surgical complications, and thus far one patient developed mild lymphedema with an average follow up of 10 months. At the clinic follow up, ICG and SPY angiography were used to confirm intact lymphatic conduits with an uptake of ICG across the axilla. This study supports LYMPHA as a feasible and effective method for lymphedema prevention. Full article

(1) Background: Nowadays, the use of microsurgical free flaps is a standard operative procedure in reconstructive surgery. Still, thrombosis of the microanastomosis is one of the most fatal postoperative complications. Clinical evaluation, different technical devices and laboratory markers are used to monitor critical flap perfusion. Macrophage migration inhibitory factor (MIF), a structurally unique cytokine with chemokine-like characteristics, could play a role in predicting vascular problems and the failure of flap perfusion. (2) Methods: In this prospective observational study, 26 subjects that underwent microsurgical reconstruction were observed. Besides clinical data, the number of blood leukocytes, CRP and MIF were monitored. (3) Results: Blood levels of MIF, C-reactive protein (CRP) and leukocytes increased directly after surgery. Subjects that needed surgical revision due to thrombosis of the microanastomosis showed significantly higher blood levels of MIF than subjects without revision. (4) Conclusion: We conclude that MIF is a potential and innovative indicator for thrombosis of the microanastomosis after free flap surgery. Since it is easy to obtain diagnostically, MIF could be an additional tool to monitor flap perfusion besides clinical and technical assessments. Full article

Background. Over the last few years, advances in technologies and digital imaging have led to the introduction of systems that enable a new approach to microsurgery and supermicrosurgery. The exoscope is a new magnification system that provides a 3D image of the surgical field: microsurgical procedures can be performed with the aid of this instrument. Here, we describe our preliminary experience with a high-definition 3D exoscope (VITOM^®, Karl Storz, Tuttlingen, Germany), evaluating the characteristics of the instrument, and also its use as a magnification device for microanastomosis training. Methods. Six microsurgeons with various levels of experience were asked to perform three end-to-end anastomoses and two end-to-side anastomoses on latex vessel models, using, as a magnification system, the VITOM^® 3D 4K exoscope. None of the surgeons involved had previous experience with the exoscope, with robotic surgery, with endoscopic surgery, nor with training simulators. Results. The results of the reported evaluation of the tool’s qualities, (VITOM Quality Assessment Tool) included: a good focusing of the surgical field; high image quality; strong luminance; good magnification; clear stereoscopy; and excellent freedom of movement. The exoscope proved to be user-friendly. A constant reduction in the time needed to perform the microsurgical anastomosis at each exercise was recorded. Among other advantages were the easy switching from the magnified image to the macroscopic view, superior ergonomics allowing a relaxed posture while performing the anastomosis, adequate space, and a convenient setting for the assistants to view the operating field. Conclusions. Our study showed that the exoscope VITOM 3D can be successfully used as a magnification tool for microsurgical anastomosis on synthetic vessels, and that it can also be helpful during training courses in microsurgery. Full article