Invasive Vascular Surgery Research Articles

Celebrating 100 years of the academic chair of surgery at St Mary’s Hospital, London

On 26 April 2023, past and present members of the department of surgery and cancer as well as those of wider supporting medical specialties of St Mary’s Hospital (SMH), London, congregated at the Royal Society under the headship of Professor Ara Darzi to celebrate 100 years since the establishment of an academic chair of surgery at SMH. The day also sought to recognise the global impact this institution has had on the surgical field over the past century and to look forwards to the major innovations that will shape the next. The event was divided into nine key sessions: cancer and minimally invasive surgery, vascular surgery, trauma and orthopaedic surgery, medicine’s impact on surgery, design, surgical education, artificial intelligence and digital health, patient safety, and allied technologies. In this article, we describe the founding of academic surgical units in the UK, and also present the key surgical ‘firsts’, breakthroughs and innovations realised at SMH in each of these realms. We finish with a look forwards to what the future holds for this institution and indeed the field of surgery as a whole.

How network structures affect the 2D-3D registration of cardiovascular images

Pre-operative and intra-operative vascular image registration plays an important role in the navigation of minimally invasive vascular interventional surgery (MIVI). Deep learning methods perform excellently in the balance of time consumption and registration accuracy. Optimal network structure is hard to construct due to the indirect correlation between convolution operation and vascular characteristics. In this paper, we compare the performance of various CNN models to find the most suitable network structure for vascular image registration. The effects of different convolution submodules are also discussed to optimize the network structures. Experiments on patients suffering from different cardiovascular diseases are conducted to evaluate the robustness of CNN models. Networks covered in this paper are all suitable for vascular image registration with the registration error within 1 mm or 1 degree, while Alex-reg outperforms the others and achieves the best registration result.

Lethal nitrous oxide (N2O) intoxication during surgery: the contribution of immunohistochemistry in identifying the cause of death: a case report

BackgroundNitrous oxide (N2O) is a gas used in medicine for its analgesic, anxiolytic and amnesic properties. It is a drug considered safe if adequately administered. In the literature, accidental N2O-related deaths are rare. They are mostly related to inhalation of this substance for recreational and autoerotic purposes; rarely are reported deaths due to incorrect administration of medical gas in anesthesia. The diagnosis of death from acute N2O intoxication is complex and is generally an exclusion diagnosis: the macroscopic and microscopic post-mortem signs are entirely nonspecific. Furthermore, the circumstantial data are not always supportive and can even be confusing, mainly if the death occurred inside a hospital.Case presentationWe describe a particular case of death from acute nitrous oxide poisoning in a hospital environment, of a Caucasian male of 72-years-old. The intoxication occurred during a minimally invasive vascular surgery due to an incorrect assembly of the supply lines of medical gases (O2 and N2O). The identification of the cause of death resulted from the analysis of circumstantial data, macroscopic and microscopic autoptic findings, and immunohistochemical investigations based on the search for antibodies anti E-selectin, P-selectin, and HIF 1-α.ConclusionAlthough not pathognomonic of asphyxiation by N2O, the latter molecules are a valid and early marker of hypoxic insult. Therefore, in concert with all other findings, it may constitute valid support for the forensic pathologist to ascertain the cause of death in case of suspected intoxication by N2O.

Screening of factors influencing catheter rotation of a vascular interventional surgical robot using design of experiment approach

Over the past decades, Vascular Interventional Surgery Robots (VISR) have been developed to address the risks associated with X-rays used in minimally invasive vascular surgery procedures. Manipulation of over-the-wire catheters is necessary to perform complex surgery but requires high forces on the robot's end effector during rotational movements. The VISR under study mimics the physician's fingers by rolling the catheter between two planar surfaces to rotate it. In this study, an experimental set-up is used to replicate this grasping method, also used in other VISR [1, 2]. The parameters of the gripping surfaces are investigated to maximise the torque delivered to the catheter and minimise the forces required at the robot's end-effector. The implemented design of experiment (DOE) demonstrated that large and soft gripping surfaces could achieve this compromise. By adjusting these parameters, sufficient torque can be achieved on the catheter.

Transfer Learning for Nonrigid 2D/3D Cardiovascular Images Registration.

Cardiovascular image registration is an essential approach to combine the advantages of preoperative 3D computed tomography angiograph (CTA) images and intraoperative 2D X-ray/digital subtraction angiography (DSA) images together in minimally invasive vascular interventional surgery (MIVI). Recent studies have shown that convolutional neural network (CNN) regression model can be used to register these two modality vascular images with fast speed and satisfactory accuracy. However, CNN regression model trained by tens of thousands of images of one patient is often unable to be applied to another patient due to the large difference and deformation of vascular structure in different patients. To overcome this challenge, we evaluate the ability of transfer learning (TL) for the registration of 2D/3D deformable cardiovascular images. Frozen weights in the convolutional layers were optimized to find the best common feature extractors for TL. After TL, the training data set size was reduced to 200 for a randomly selected patient to get accurate registration results. We compared the effectiveness of our proposed nonrigid registration model after TL with not only that without TL but also some traditional intensity-based methods to evaluate that our nonrigid model after TL performs better on deformable cardiovascular image registration.

Two-Year Results of Robotic Surgery for Aorto Iliac Occlusive Disease: Current Place in Minimally Invasive Vascular Surgery

Two-Year Results of Robotic Surgery for Aorto Iliac Occlusive Disease: Current Place in Minimally Invasive Vascular Surgery

Skeleton Marching-based Parallel Vascular Geometry Reconstruction Using Implicit Functions

Fast high-precision patient-specific vascular tissue and geometric structure reconstruction is an essential task for vascular tissue engineering and computer-aided minimally invasive vascular disease diagnosis and surgery. In this paper, we present an effective vascular geometry reconstruction technique by representing a highly complicated geometric structure of a vascular system as an implicit function. By implicit geometric modelling, we are able to reduce the complexity and level of difficulty of this geometric reconstruction task and turn it into a parallel process of reconstructing a set of simple short tubular-like vascular sections, thanks to the easy-blending nature of implicit geometries on combining implicitly modelled geometric forms. The basic idea behind our technique is to consider this extremely difficult task as a process of team exploration of an unknown environment like a cave. Based on this idea, we developed a parallel vascular modelling technique, called Skeleton Marching, for fast vascular geometric reconstruction. With the proposed technique, we first extract the vascular skeleton system from a given volumetric medical image. A set of sub-regions of a volumetric image containing a vascular segment is then identified by marching along the extracted skeleton tree. A localised segmentation method is then applied to each of these sub-image blocks to extract a point cloud from the surface of the short simple blood vessel segment contained in the image block. These small point clouds are then fitted with a set of implicit surfaces in a parallel manner. A high-precision geometric vascular tree is then reconstructed by blending together these simple tubular-shaped implicit surfaces using the shape-preserving blending operations. Experimental results show the time required for reconstructing a vascular system can be greatly reduced by the proposed parallel technique.

Computer‐Assisted Path Planning for Minimally Invasive Vascular Surgery

Path planning assisted by two-dimensional medical images is an essential part of minimally invasive diagnosis and treatment for cardiovascular diseases. Due to the complex background of angiography images and intricate vascular structure with multi-branch and stenoses, creating accurate pathways from angiography image is a challenge task. We present a new path planning methodology based on angiography medical images using the steady fluid dynamics. Our novel approach is useful in many medical applications, such as for computer-assisted medical images analysis and the follow-on image-guided interventions. A graph-cuts based energy function was applied to the vessel segmentation of angiography images in order to obtain boundary information. We have adopted Finite volume method (FVM) to simulate the Newtonian fluid inside the segmented blood vessels, and a set of isobars under the steady fluid condition are obtained by Meandering Triangles algorithm. The selected center points of isobars are organized to generate the directed vessels-tree, from which the vascular stenoses are automatically detected and the final surgical path is generated with branches. Our method can be used for quantitative path analysis, and we show experimental results to demonstrate that the versatility and applicability of the algorithm in obtaining single-pixel surgical path with good performance, high accuracy and less manual interventions, especially it is robust on complex vascular structures.

A simulator with an elastic guidewire and vascular system for minimally invasive vascular surgery

A simulator with an elastic guidewire and vascular system for minimally invasive vascular surgery

Compensatory force measurement and multimodal force feedback for remote-controlled vascular interventional robot

Minimally invasive vascular interventional surgery is widely used and remote-controlled vascular interventional surgery robots (RVIRs) are being developed to reduce the occupational risk of the intervening physician in minimally invasive vascular interventional surgeries. Skilled surgeon performs surgeries mainly depending on the detection of collisions. Inaccurate force feedback will be difficult for surgeons to perform surgeries or even results in medical accidents. In addition, the surgeon cannot quickly and easily distinguish whether the proximal force exceeds the safety threshold of blood vessels or not, and thus it results in damage to the blood vessels. In this paper, we present a novel method comprising compensatory force measurement and multimodal force feedback (MFF). Calibration experiments and performance evaluation experiments were carried out. Experimental results demonstrated that the proposed method can measure the proximal force of catheter/guidewire accurately and assist surgeons to distinguish the change of proximal force more easily. This novel method is suitable for use in actual surgical operations.

In Memoriam: Lawrence H. Cohn, MD (1937–2016)

In Memoriam: Lawrence H. Cohn, MD (1937–2016)

Dr. Thomas J. Fogarty: The real face of minimally invasive vascular surgery

Dr. Thomas J. Fogarty: The real face of minimally invasive vascular surgery

The role of simulation in neurosurgery.

In an era of residency duty-hour restrictions, there has been a recent effort to implement simulation-based training methods in neurosurgery teaching institutions. Several surgical simulators have been developed, ranging from physical models to sophisticated virtual reality systems. To date, there is a paucity of information describing the clinical benefits of existing simulators and the assessment strategies to help implement them into neurosurgical curricula. Here, we present a systematic review of the current models of simulation and discuss the state-of-the-art and future directions for simulation in neurosurgery. Retrospective literature review. Multiple simulators have been developed for neurosurgical training, including those for minimally invasive procedures, vascular, skull base, pediatric, tumor resection, functional neurosurgery, and spine surgery. The pros and cons of existing systems are reviewed. Advances in imaging and computer technology have led to the development of different simulation models to complement traditional surgical training. Sophisticated virtual reality (VR) simulators with haptic feedback and impressive imaging technology have provided novel options for training in neurosurgery. Breakthrough training simulation using 3D printing technology holds promise for future simulation practice, proving high-fidelity patient-specific models to complement residency surgical learning.

Fast and stable guidewire simulator for minimally invasive vascular surgery.

In recent years, minimally invasive vascular surgery is widely applied in treatment of cardiovascular diseases, and the manipulation of the guidewire is the essential skill for this surgery. Lots of time and money have to be taken to achieve the skill. In this paper, we present a multithreading guidewire simulator which can help the apprentice to gain the skill and modeling the guidewire is the core technique of the simulator. The guidewire is modeled by a fast and stable method based on the Cosserat theory of elastic rods. The method describes the behavior of the guidewire with the Lagrange equations of motion and it uses the penalty method to maintain constraints. We further propose a simplified solving procedure for the guidewire model. Finally, some experiments are conducted to evaluate the effectiveness of this model.

Operation and force analysis of the guide wire in a minimally invasive vascular interventional surgery robot system

To develop a robot system for minimally invasive surgery is significant, however the existing minimally invasive surgery robots are not applicable in practical operations, due to their limited functioning and weaker perception. A novel wire feeder is proposed for minimally invasive vascular interventional surgery. It is used for assisting surgeons in delivering a guide wire, balloon and stenting into a specific lesion location. By contrasting those existing wire feeders, the motion methods for delivering and rotating the guide wire in blood vessel are described, and their mechanical realization is presented. A new resistant force detecting method is given in details. The change of the resistance force can help the operator feel the block or embolism existing in front of the guide wire. The driving torque for rotating the guide wire is developed at different positions. Using the CT reconstruction image and extracted vessel paths, the path equation of the blood vessel is obtained. Combining the shapes of the guide wire outside the blood vessel, the whole bending equation of the guide wire is obtained. That is a risk criterion in the delivering process. This process can make operations safer and man-machine interaction more reliable. A novel surgery robot for feeding guide wire is designed, and a risk criterion for the system is given.

Partial absence of superior vena cava in an adult patient

Absence of the superior vena cava (SVC) is a rare variety of vascular anomaly. The purpose of this report is to describe the computed tomography (CT) findings of the partial absence of the SVC without persistent left SVC in a patient with no evidence of congenital cardiovascular disease and no prior history of central venous instrumentation. A 77-year-old woman with a history of colon cancer underwent thoracoabdominal CT imaging because of abdominal pain of uncertain cause. No tumor recurrence was observed. A complicated"investigation" confirmed a thymoid cancer surgery back in 1976, which was accompanied by resection of the SVC and the left brachiocephalic vein because of their invasion. Owing to the absence of the SVC and bilateral brachiocephalic veins, caval hypertension developed in the patient, resulting in the dilation of cavo-caval anastomoses. In addition, new anastomoses were opened. The clinical significance and possible embryogenesis of this anomaly are discussed. The extremely rare condition of the partial absence of the SVC appeared with subcutaneous dilated, tortuous collaterals in an asymptomatic adult patient. This anomaly is becoming clinically more relevant with the increasing use of minimally invasive vascular surgery.

Multi-degree-of-freedom ultrasonic micromotor for guidewire and catheter navigation: The NeuroGlide actuator

A 240-μm diameter ultrasonic micromotor is presented as a potential solution for an especially difficult task in minimally invasive neurosurgery, navigating a guidewire to an injury in the neurovasculature as the first step of surgery. The peak no-load angular velocity and maximum torque were 600 rad/s and 1.6 nN-m, respectively, and we obtained rotation about all three axes. By using a burst drive scheme, open-loop position and speed control were achieved. The construction method and control scheme proposed in this study remove most of the current limitations in minimally invasive, catheter-based actuation, enabling minimally invasive vascular surgery concepts to be pursued for a broad variety of applications.

Design of the Control System and Home Point Positioning Device for Minimally Invasive Vascular Interventional Surgery Robot

To realize the accurate positioning and stable holding of surgical tools by minimally invasive vascular interventional surgery(VIS) robot,a control system and a home point positioning device are designed.Constitutions of the robot system and its upper-lower control system based on PMAC(programmable multi-axis controller) are introduced firstly. Meanwhile,the quintic interpolation motion planning and three-loop PID algorithms are designed,which improve both the robot's response speed and stability.To find the base point of the robot's motion,the home point positioning method and device are proposed based on Hall sensors and information of motor motion.The experiment results show that the presented home point positioning device works stably and accurately.

Implicit Reconstruction of Vasculatures Using Bivariate Piecewise Algebraic Splines

Vasculature geometry reconstruction from volumetric medical data is a crucial task in the development of computer guided minimally invasive vascular surgery systems. In this paper, a technique for reconstructing the geometry of vasculatures using bivariate implicit splines is developed. With the proposed technique, an implicit geometry representation of the vascular tree can be accurately constructed based on the voxels extracted directly from the surface of a certain vascular structure in a given volumetric medical dataset. Experimental results show that the geometric representation built using our method can faithfully represent the morphology and topology of vascular structures. In addition, both the qualitative and the quantitative validations have been performed to show that the reconstructed vessel geometry is of high accuracy and smoothness. An virtual angioscopy system has been implemented to indicate one of the strengths of our proposed method.

The requirement for smart catheters for advanced endovascular applications

Endovascular techniques are well established in minimally invasive vascular surgery. Stent-graft technology is evolving. This will allow more complex aortic pathology to be treated. Current limitations in this equipment include the reliance on selective catheters along with trial and error to cannulate visceral or aortic arch branch vessels. This can lead to prolonged operations with increased radiation and contrast load to the patient with inevitable increase in peri-operative morbidity. A smart catheter that could expedite target vessel catheterization, minimize repeat catheter changes, and provide greater haptic feedback would enhance the endovascular surgeon's armamentarium. This would lead to broader and safer application of endovascular surgery.