Matías de la Fuente

• PhD
• RWTH Aachen University

Conventional navigation systems (CNS) in surgery require strong spatial cognitive abilities and hand-eye coordination. Augmented Reality Navigation Systems (ARNS) provide 3D guidance and may overcome these challenges, but their accuracy and efficiency compared to CNS have not been systematically evaluated. In this randomized crossover study with 36...

Purpose Although the literature shows that robotic assistance can support the surgeon, robotic systems are not widely spread in clinics. They often incorporate large robotic arms adopted from the manufacturing industry, imposing safety hazards when in contact with the patient or surgical staff. We approached this limitation with a modular dual robo...

The current gold standard of computer-assisted jaw reconstruction includes raising microvascular bone flaps with patient-specific 3D-printed cutting guides. The downsides of cutting guides are invasive fixation, periosteal denudation, preoperative lead time and missing intraoperative flexibility. This study aimed to investigate the feasibility and...

Augmented Reality (AR) Head Mounted Displays (HMDs) hold promise in revolutionizing surgical procedures by providing enhanced visualization and information overlay capabilities. This study evaluates and compares Optical See-Through (OST) and Video See-Through (VST) AR devices across key performance metrics crucial for surgical applications: depth p...

Augmented Reality (AR) Head Mounted Displays (HMDs) hold promise in revolutionizing surgical procedures by providing enhanced visualization and information overlay capabilities. This study evaluates and compares Optical See-Through (OST) and Video See-Through (VST) AR devices across key performance metrics crucial for surgical applications: depth p...

Objective: The gold standard of oral cancer (OC) treatment is diagnostic confirmation by biopsy followed by surgical treatment. However, studies have shown that dentists have difficulty performing biopsies, dental students lack knowledge about OC, and surgeons do not always maintain a safe margin during tumor resection. To address this, biopsies an...

Introduction: Extracorporeal shock wave therapy is a non-invasive and effective option for treating various musculoskeletal disorders. Recent literature indicates that the parameters for extracorporeal shock wave therapy, such as the optimal intensity, treatment frequency, and localization, are yet to be determined. Studies reporting on the effects...

Objectives Focused ultrasound is mainly known for focal ablation and localized hyperthermia of tissue. During the last decade new treatment options were developed for neurological indications based on blood-brain-barrier opening or neuromodulation. Recently, the transcranial application of shock waves has been a subject of research. However, the me...

Background Soft-tissue swelling after limb fractures in pediatric patients is well known to be a risk factor for developing acute compartment syndrome (ACS). Clinical assessment alone is uncertain in specific cases. Recently, we proposed a non-invasive ultrasound-based method to objectify muscle compartment elasticity for monitoring. We hypothesize...

Purpose: In bone surgery specialties, like orthopedics, neurosurgery, and oral and maxillofacial surgery patient safety and treatment success depends on the accurate implementation of computer-based surgical plans. Unintentional plan deviations can result in long-term functional damage to the patient. With on-site teleoperation, the surgeon operat...

Ballistic devices that generate radial pressure waves are used for the treatment of different therapeutic indications. In order to assess the effectiveness of these devices and to interpret and transfer the results of clinical trials, it is important to know their acoustic output. In this paper, two ballistic devices and their reproducibility at di...

Objectives: Since the 1980s, robotic arms have been transferred from industrial applications to orthopaedic surgical robotics. Adverse events are frequent and often associated with the adopted powerful and oversized anthropomorphic arms. The FDA's 510(k) pathway encourages building on such systems, leading to the adoption of hazards, which is know...

Background: Soft tissue swelling after limb fractures in pediatric patients is well known to be a risk factor for developing acute compartment syndrome (ACS). Clinical assessment alone is uncertain in specific cases. Recently, we proposed a non-invasive ultrasound based method to objectify muscle compartment elasticity for monitoring. We hypothesiz...

Radial shock wave therapy is used for different therapeutic indications. In order to assess the effect on the treated tissue, it is important to know the sound field parameters. However, it is challenging to measure the pressure curves of ballistic devices, especially at high pulse repetition rates. In the new standard IEC 63045:2020 two possibilit...

Background Extracorporeal shock wave therapy (ESWT) is a widely considered treatment option for Achilles tendinopathy. Line-focused ESWT is a novel technique treating a larger tendon area than point-focused ESWT. Monitoring capacities of clinical symptoms with ultrasound under ESWT treatment are unknown. Hypothesis Point- and line-focused ESWT hav...

Purpose Current surgical robotic systems are either large serial arms, resulting in higher risks due to their high inertia and no inherent limitations of the working space, or they are bone-mounted, adding substantial additional task steps to the surgical workflow. The robot presented in this paper has a handy and lightweight design and can be easi...

Purpose Cooperative surgical systems enable humans and machines to combine their individual strengths and collaborate to improve the surgical outcome. Cooperative telemanipulated systems offer the widest spectrum of cooperative functionalities, because motion scaling is possible. Haptic guidance can be used to assist surgeons and haptic feedback ma...

The identification of femoral landmarks is a common procedure in multiple academic fields. Femoral bone coordinate systems are used particularly in orthopedics and biomechanics, and are defined by landmarks, axes and planes. A fully automatic detection overcomes the drawbacks of a labor-intensive manual identification. In this paper, a new automati...

Purpose The development of acute compartment syndrome is a serious threat to trauma patients. The clinical assessment alone is not reliable enough to determine the need for fasciotomy in many cases. The Physician´s assessment of the elasticity of the muscle compartment might be particularly important to objectively evaluate the pressure in this enc...

Risk classes defined by MDR and FDA for state-of-the-art surgical robots based on their intended use are not suitable as indicators for their hazard potential. While there is a lack of safety regulation for an increasing degree of automation as well as the degree of invasiveness into the patient's body, adverse events have increased in the last dec...

Purpose: Close monitoring of patients at risk to develop an acute compartment syndrome (ACS) is well known to be essential. There is a relevant risk that clinical assessment alone is not reliable enough. Reliable assessment of the elasticity of the muscle compartment might represent a helpful tool to assess the pressure in this enclosed space. The...

Purpose Surgical robotics has developed throughout the past 30 years resulting in more than 5000 different approaches proposed for various surgical disciplines supporting different surgical task sequences and differing ways of human–machine cooperation or degrees of automation. However, this diversity of systems influences cost as well as usability...

Proper cup alignment is crucial in total hip arthroplasty for reducing impingement risks, dislocations and wear. The Lewinnek “safe zone” is often used in clinical routine. This safe zone does not consider functional aspects and dislocation can occur even when the cup is oriented within the safe zone. Functional safe zones based on the hip range of...

Cavitation is a major fracture mechanism in extracorporeal shock wave lithotripsy (ESWL). However, it can cause tissue trauma and its effects on kidney stones and surrounding tissue are not fully understood. Therefore experimental setups enabling systematic parameter studies are crucial. We developed and evaluated a testing rig comprising three mea...

Surgical robots have been introduced in the field of Computer Assisted Surgery (CAS) to assist the surgeon by providing an accurate link between the computer-based plan and the exact (a) positioning or (b) dynamic path control of an instrument on the operating site respectively. Whereas initial systems mostly have been based on an active supervisor...

Within the further development of a special mechanical representation of the human circulatory system the CVELoop at the Department of Cardiovascular Engineering at RWTH Aachen University, a contractive MockHeart was developed. This MockHeart simulates a healthy heart in the CVELoop. In opposition to all previous cardiovascular system simulators, t...

The success rate of extracorporeal shock wave therapy (ESWT) for fracture nonunions in human medicine (i.e., radiographic union at six months after ESWT) is only approximately 75%. Detailed knowledge regarding the underlying mechanisms that induce bio-calcification after ESWT is limited. We analyzed the biological response within mineralized tissue...

Accurate planning transfer is a prerequisite for successful operative care. For different applications, diverse computer‐assisted systems have been developed and clinically evaluated. This paper presents the implementation and evaluation of a new modular concept. The approach is based on passive application specific kinematics that are semi‐automat...

A substantial body of evidence supports the use of extracorporeal shock wave therapy (ESWT) for fracture nonunions in human medicine. However, the success rate (i.e., radiographic union at six months after ESWT) is only approximately 75%. Detailed knowledge regarding the underlying mechanisms that induce bio-calcification after ESWT is limited. The...

Purpose: Assess electromagnetically guided in situ fenestration of juxtarenal aortic stent grafts in an in vivo model. Methods: Using a newly developed electromagnetic guidance system together with a modified, electromagnetically guidable catheter with steerable tip, an electromagnetically trackable guidewire and a custom in situ fenestrateable...

Background The benefit of revascularization for functional recovery depends on the presence of viable myocardial tissue. Objective Myocardial deformation imaging allows determination of myocardial viability. Methods In a first approach, we assessed the optimal cutoff value to determine preserved viability by layer-specific echocardiographic myocard...

Modern operating rooms (OR) undergo a constant rise in the amount and complexity of technical systems. Due to a lack of inter-device communication and integration, each device works stand-alone resulting in redundant sensors, input devices, monitors and—last but not least—crowded ORs and error prone human- machine-interaction. Therefore, various ma...

Robotic surgical systems reduce the cognitive workload of the surgeon by assisting in guidance and operational tasks. As a result, higher precision and a decreased surgery time are achieved, while human errors are minimised. However, most of robotic systems are expensive, bulky and limited to specific applications. In this paper a novel semi-automa...

Background: To improve understanding of shockwave therapy mechanisms, in vitro experiments are conducted and the correlation between cell reaction and shockwave parameters like the maximum pressure or energy density is studied. If the shockwave is not measured in the experimental setup used, it is usually assumed that the device's shockwave parame...

Nowadays immersive three-dimensional virtual scenes have become very popular. This paper presents and provides a database of 48 head-related transfer function (HRTF) datasets and the corresponding three-dimensional ear mesh models of individual subjects, in order to select or model an HRTF dataset for binaural synthesis and auditory reproduction. F...

Revision surgery of cemented femoral stems in total hip arthroplasty is gaining more and more importance, but cement removal in revision hip arthroplasty may be technically challenging. Conventional manual cement removal can be time consuming and be associated with complications such as cortical perforation, fracture, or bone loss. The aim of this...

Identification of viable myocardial tissue is important for patients with a low left ventricular ejection fraction, since revascularization is effective only if the affected region is viable. After cineangiographic identification of occluded coronary vessels, the myocardial viability is usually determined using cardiac MRI or SPECT. Alternatively,...

Abstract This work presents concepts for complex endovascular procedures using electromagnetic navigation technology (EMT). Navigation software interfacing a standard commercially available navigation system was developed, featuring registration, electromagnetic field distortion correction, breathing motion detection and gating, and state-of-the-ar...

Applying shock waves to the heart has been reported to stimulate the heart and alter cardiac function. We hypothesized that shock waves could be used to diagnose regional viability. We used a Langendorff model to investigate the acute effects of shock waves at different energy levels and times related to systole, cycle duration and myocardial funct...

Seismocardiography (SCG) is a noninvasive technique for recording cardiac vibrations. Changes in these waves have been correlated with chronic and acute alterations in myocardial function. This analysis is complex and clinical integration limited. The current study aimed to simplify the utilization of SCG by fast Fourier transformation for a reliab...

Objective: Shock waves applied to the heart were reported to improve cardiac function. We hypothesized that shock waves could also stimulate the myocardium to provide a regional vitality diagnostic. Method: We used a Langendorff model to investigate the acute effects of shock waves on the conduction system and myocardial function. Results: We fou...

Oxidative stress in immune cells of adult obese mice fed during their adolescence with a high (60%) fat diet - Volume 72 Issue OCE1 - O. Hernández, L. Marín, L. E. Díaz, G. Baccan, S. Gómez-Martínez, A. Marcos, M. De La Fuente

Effect of an early fat-rich diet on immune cell functions and redox status of adolescent mice - Volume 72 Issue OCE1 - O. Hernández, L. E. Díaz, G. Baccan, A. Gheorghe, A. Marcos, M. De La Fuente

Abstract In the proximal femur, a high accuracy of implant placement reduces the risk of mechanical failure. We have tested a new computer-assisted planning and navigation system based on two-dimensional fluoroscopy using the so-called zero-dose C-arm navigation approach to optimise implant placement in fracture fixation and hip resurfacing. The ai...

Abstract Currently, there are only a small number of robotic systems used in various surgical fields. As modified industrial robot systems have shown significant limitations in the past, specialized kinematic solutions have been proposed for specific surgical applications. The majority of these systems are designed for specific applications in only...

Pertrochanteric femoral fractures are common and intramedullary nailing with a proximal femoral nail (PFNA®) is an accepted method for the surgical treatment. Accurate guide wire and subsequent hardware placement in the femoral neck is believed to be essential in order to avoid mechanical failure. Malpositioned implants may lead to rotational or an...

Zusammenfassung Hintergrund Ziel dieser Studie war die Evaluation eines neuen computergestützten 2-D-fluoroskopiebasierten Planungs- und Navigationssystems mit integrierter strahlungsfreier Röntgenbildvorschau (sog. „Zero-dose-C-Arm-Navigation“), das den Operateur bei der Implantation kanülierter Schrauben in den Schenkelhals unterstützt. Material...

Dynamic hip screw (DHS) insertion for the fixation of lateral femoral neck fractures is an accepted surgical treatment method. A computer-assisted planning and navigation system based on 2D fluoroscopy has been developed for guidewire insertion in order to perform screw placement. The image acquisition process was supported by a radiation-saving pr...

Pertrochanteric femoral fractures are common and intramedullary nailing is an accepted method for their surgical treatment. Accurate placement of the implant is essential to ensure fixation. The conventional technique can require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based...

The aim of this study was the evaluation of a new computer-assisted planning and navigation system based on 2D-fluoroscopy for guidewire insertion in order to perform cannulated screw placement into the femoral neck. The image acquisition process was supported by a radiation-saving procedure called Zero-dose C-arm navigation. In the context of a sa...

Accurate placement of cannulated screws is essential to ensure fixation of medial femoral neck fractures. The conventional technique may require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on 2D fluoroscopy for guide wire placement in the femoral neck has been developed to...

Despite controversial discussions, hip resurfacing at the moment seems to be the most bone-sparing surgical procedure of the femoral bone when implanting hip endoprostheses. Main risks are septic and aseptic loosening and necroses of the coxal end of the femoral bone mainly influenced by the periprosthetic allocation of bone cement. Because of a la...

Trepanation of the skull is a common procedure in neurosurgery with the problems of dural tears and wide cutting gaps. A hand-guided instrument containing a soft-tissue preserving saw whose cutting depth is automatically adapted on the basis of a-priori data (CT, MRI) is envisioned to reduce these problems. In this paper a major part of the system,...

Visualization of electromagnetically tracked instruments in pre- or intra-interventional fluoroscopic images requires a registration process between the coordinate systems of both modalities. We present in this paper a new approach for performing this procedure by using only two external fiducial markers with integrated electromagnetic sensors whic...

Medical robots are superior to freehand manipulation if an accurate, precise, and time-efficient implementation of a preplanned intervention is required. In the first part of this contribution a new modular minirobot for automatic ultrasound-based bone cement detection followed by subsequent cement milling in revision total hip replacement is prese...

The efficiency and success of computer-assisted fluoroscopic navigation systems mainly depend on the quality of the process of image acquisition: obtaining the correct view of anatomic structures, relative orientation of multiplanar X-ray images and the necessary amount of radiation dose. These systems may be optimised by using a system called zero...

Prosthesis-specific mechanical alignment instruments for the precise and reproducible positioning of the femoral component constitute one of the major improvements in modern hip resurfacing prostheses. However, mechanical failure of the femoral component is mostly attributable to the surgical technique, and in particular to notching of the femoral...

The technology for localization of surgical tools with respect to the patient's reference coordinate system in three to six degrees of freedom is one of the key components in computer aided surgery. Several tracking methods are available, of which optical tracking is the most widespread in clinical use. Optical tracking technology has proven to be...

The localization of surgical tools and the patient’s reference coordinate system in three to six degrees of freedom is one of the key technologies in computer aided surgery. Several tracking methods are available, among which optical tracking is the most widespread in clinical use. Optical tracking technology has well proven to be a reliable method...

Adult animals that had been subjected to a single prolonged episode of maternal deprivation (MD) [24 h, postnatal day (PND) 9-10] show long-term behavioral alterations that resemble specific symptoms of schizophrenia. Moreover, at adolescence MD rats showed depressive-like behavior and altered motor responses. According to the neurodevelopmental hy...

In total hip replacement (THR) one technical factor influencing the risk of dislocation is cup orientation. Computer-assisted surgery systems allow for cup navigation in anatomy-based reference frames. The pelvic coordinate system most used for cup navigation in THR is based on the mid-sagittal plane (MSP) and the anterior pelvic plane (APP). From...

The aim of trajectory navigation is to position a surgical instrument along a planned trajectory. Computer assisted navigation systems show maximal flexibility but are limited by the costs and accuracy of the used optical tracking system and the human errors during free-hand navigation. Robotic devices can reach highest accuracy but are expensive a...

In this paper a new approach for a control and safety architecture for a modular task adaptable medical robot is described. The concept has been evaluated with the MINARO robot, which was developed in the OrthoMIT framework for revision total hip replacement (RTHR), being one of several possible applications. By modularizing the system we tried to...

The correct determination of the mechanical leg axis (so called Mikulicz-Line) is cruicial step for the correct alignment of prosthesis components in Total Knee Arthroplasty (TKA). The newly developed “genALIGN”-system uses a force-torque sensor to directly measure the torques induced by a deviation from the mechanical axis. During surgery, the dev...

The most essential improvement of modern hip resurfacing arthroplasty is the metal-on-metal bearing as well as the integration of a procedure for the exact and repeatable positioning of the femoral component through a specific mechanical alignment instrument. Nevertheless, the main reasons for early implant failure are mal-positioning of the femora...

Einleitung: Der moderne Oberflächenersatz des Hüftgelenkes bietet eine Alternative in der Behandlung der Coxarthrose für den jungen und aktiven Patienten. Dennoch gelten vorwiegend operationstechnische Gründe, insbesondere die Schädigung der Femurhalskortikalis („Notching des Schenkelhalses“) wie auch eine ungenaue Prothesenpositionierung während d...

Precise knowledge of the mid-sagittal plane is important for the assessment and correction of several deformities. Furthermore, the mid-sagittal plane can be used for the definition of standardized coordinate systems such as pelvis or skull coordinate systems. A popular approach for mid-sagittal plane computation is based on the selection of anatom...

Resurfacing arthroplasty represents an alternative method to total hip replacement especially for the young and active patient. The main reasons for early implant failure are mal-positioning of the femoral component and notching of the femoral neck during femoral head preparation. In the context of a cadaver study of formalin-fixed cadaveric full b...

Objective Validation of medical image segmentation algorithms is an open question, considering variance of individual pathologies and the related clinical requirements for accuracy. In this paper, we propose a validation metric capable to distinguish between an over and under-segmentation and account for different clinical applications. Materials a...

The introduction of fluoroscopy based navigation systems has been found to generally result in a significantly reduced amount of radiation dose for the patient as well as the OR-team. These systems enable the virtual projection of surgical instruments inside intraoperative acquired X-ray images. In order to implement this procedure, the position an...

Metal-on-metal hip resurfacing arthroplasties represent an alternative to total hip arthroplasties for young and active patients, enabling the preservation of intact femoral bone and therefore improving the prognosis for future hip joint replacements. Follow-up studies have shown that the main reasons for early implant failure are mal-orientation o...

Due to the difficulty of determining the 3D boundary of the cement-bone interface in Revision Total Hip Replacement (RTHR), the removal of the distal intra-femoral bone cement can be a time-consuming and risky operation. Within the framework of computer- and robot-assisted cement removal, the principles and first results of an automatic detection a...

Many computer assisted surgery systems are based on intraoperative x-ray images. To achieve reliable and accurate results these images have to be calibrated concerning geometric distortions, which can be distinguished between constant distortions and distortions caused by magnetic fields. Instead of using an intraoperative calibration phantom that...

Revision total hip replacement (RTHR), especially the removal of the distal femoral bone cement, is an issue where the potential of advanced surgery systems could be applied. A new approach for RTHR based on calibrated multiplanar fluoroscopic images is presented, enabling a D reconstruction of the femoral bone cement based on few (3–5) projections...

Computer-assisted cement removal out of the femoral medullary canal requires the exact definition of the plug's shape within a 3D coordination system. Aiming at a sufficiently precise reconstruction based on segmentation of just a few 2D X-ray images a special mathematic procedure is needed for automatic surface interpolation. The geometric specifi...

A Mode ultrasound based registration ollcrs a non invasive solution Ibr transcutaneous palpalmn and registration of hone surface points in computer and robot assisted surgery. Manufacturing lolciiiiuvs iiuiy cause a rotational shift between the transducer's supposed and it's real beam axis resulting in a transversal and an axial shift. In order to...

Since several years computer as well as robot technology is introduced into orthopaedic surgery. However it is discussed controversely. What are the advantages and problems of automation technology in surgery? This paper gives an overview of technical approaches and possibilities. Developmental potentials especially related to robotic assistance sy...

During x-ray based navigation a number of errors causes distortions in the output image. These errors lead to a fail position of the surgical instrument relative to the patients anatomy. To minimize these influences and to develop dewarping techniques an exact error source identification is necessary. This paper examines the mechanical shift of the...

The main objective of the MINARO project (Minimal Invasive NAvigation and RObotics) is the development of a modular intraoperative planning system for fluoroscopy based total hip revision surgery. Especially the distal cement removal can be a challenging problem. To avoid exhaustive x-ray imaging a navigation system should be used, nevertheless, th...