Paul Rea

The precision of four commonly used surgical landmarks for locating the facial nerve in anterograde parotidectomy in humans.

In addition to using intra-operative facial nerve monitoring in helping to locate the position of the facial nerve in anterograde parotidectomy, numerous soft tissue and bony landmarks have been proposed to assist the surgeon in the early identification of this nerve. There is still dispute within the literature as to the most effective method, if any, of locating the nerve. The purpose of this study was to measure the distance (in twenty-six embalmed cadavers) from four of the most commonly used surgical landmarks to the main trunk of the facial nerve-the posterior belly of digastric muscle (PBDM), the tragal pointer (TP), the junction between the bony and cartilaginous ear canal (EAM) and the tympanomastoid suture (TMS). The main trunk of the facial nerve was found 5.5+/-2.1mm from the PBDM, 6.9+/-1.8 mm from the TP, 10.9+/-1.7 mm from the EAM and 2.5+/-0.4 mm from the TMS. From this, the TMS can be used as a reliable indicator for locating the main trunk of the facial nerve. In addition, this study also demonstrated a statistically significant difference between the sexes in relation to the two bony landmarks used here, the EAM and the TMS, with the facial nerve found further away from those landmarks in females compared to males. With the advent of 3D construction and reformatting of images, these values may come to the forefront in pre-operative planning for locating the facial nerve in anterograde parotidectomy.

Real-time Medical Visualization of Human Head and Neck Anatomy and its Applications for Dental Training and Simulation

The Digital Design Studio and NHS Education Scotland have developed ultra-high definition real-time interactive 3D anatomy of the head and neck for dental teaching, training and simulation purposes. In this paper we present an established workflow using state-of-the-art 3D laser scanning technology and software for design and construction of medical data and describe the workflow practices and protocols in the head and neck anatomy project. Anatomical data was acquired through topographical laser scanning of a destructively dissected cadaver. Each stage of model development was clinically validated to produce a normalised human dataset which was transformed into a real-time environment capable of large-scale 3D stereoscopic display in medical teaching labs across Scotland, whilst also supporting single users with laptops and PC. Specific functionality supported within the 3D Head and Neck viewer includes anatomical labelling, guillotine tools and selection tools to expand specific local regions of anatomy. The software environment allows thorough and meaningful investigation to take place of all major and minor anatomical structures and systems whilst providing the user with the means to record sessions and individual scenes for learning and training purposes. The model and software have also been adapted to permit interactive haptic simulation of the injection of a local anaesthetic.

3D visualisation for education, diagnosis and treatment of lliotibial band syndrome

The evolution of medical imaging technologies and computer graphics is leading to dramatic improvements for medical training, diagnosis and treatment, and patient understanding. This paper discusses how volumetric visualization and 3D scanning can be integrated with cadaveric dissection to deliver benefits in the key areas of clinician-patient communication and medical education. The specific area of medical application is a prevalent musculoskeletal disorder-iliotibial (IT) band syndrome. By combining knowledge from cadaveric dissection and volumetric visualization, a virtual laboratory was created using the Unity 3D game engine, as an interactive education tool for use in various settings. The system is designed to improve the experience of clinicians who had commented that their earlier training would have been enhanced by key features of the system, including accurate three-dimensional models generated from computed tomography, high resolution cryosection images of the Visible Human dataset, and surface anatomy generated from a white light scan of an athlete. The finding from the virtual laboratory concept is that knowledge gained through dissection helps enhance the value of the model by incorporating more detail of the distal attachments of the IT band. Experienced clinicians who regularly treat IT band syndrome were excited by the potential of the model and keen to make suggestions for future enhancement.

Development of a Patient-Specific 3D-Printed Liver Model for Preoperative Planning

Introduction. Liver surgery is widely used as a treatment modality for various liver pathologies. Despite significant improvement in clinical care, operative strategies, and technology over the past few decades, liver surgery is still risky, and optimal preoperative planning and anatomical assessment are necessary to minimize risks of serious complications. 3D printing technology is rapidly expanding, and whilst appliactions in medicine are growing, but its applications in liver surgery are still limited. This article describes the development of models of hepatic structures specific to a patient diagnosed with an operable hepatic malignancy. Methods. Anatomy data were segmented and extracted from computed tomography and magnetic resonance imaging of the liver of a single patient with a resectable liver tumor. The digital data of the extracted anatomical surfaces was then edited and smoothed, resulting in a set of digital 3D models of the hepatic vein, portal vein with tumor, biliary tree with gallbladder, and hepatic artery. These were then 3D printed. Results. The final models of the liver structures and tumor provided good anatomical detail and representation of the spatial relationships between the liver tumor and adjacent hepatic structures and could be easily manipulated and explored from different angles. Conclusions. A graspable, patient-specific, 3D printed model of liver structures could provide an improved understanding of the complex liver anatomy and better navigation in difficult areas and allow surgeons to anticipate anatomical issues that might arise during the operation. Further research into adequate imaging, liver-specific volumetric software, and segmentation algorithms are worth considering to optimize this application.

A recommended workflow methodology in the creation of an educational and training application incorporating a digital reconstruction of the cerebral ventricular system and cerebrospinal fluid circulation to aid anatomical understanding

BackgroundThe use of computer-aided learning in education can be advantageous, especially when interactive three-dimensional (3D) models are used to aid learning of complex 3D structures. The anatomy of the ventricular system of the brain is difficult to fully understand as it is seldom seen in 3D, as is the flow of cerebrospinal fluid (CSF). This article outlines a workflow for the creation of an interactive training tool for the cerebral ventricular system, an educationally challenging area of anatomy. This outline is based on the use of widely available computer software packages.MethodsUsing MR images of the cerebral ventricular system and several widely available commercial and free software packages, the techniques of 3D modelling, texturing, sculpting, image editing and animations were combined to create a workflow in the creation of an interactive educational and training tool. This was focussed on cerebral ventricular system anatomy, and the flow of cerebrospinal fluid.ResultsWe have successfully created a robust methodology by using key software packages in the creation of an interactive education and training tool. This has resulted in an application being developed which details the anatomy of the ventricular system, and flow of cerebrospinal fluid using an anatomically accurate 3D model. In addition to this, our established workflow pattern presented here also shows how tutorials, animations and self-assessment tools can also be embedded into the training application.ConclusionsThrough our creation of an established workflow in the generation of educational and training material for demonstrating cerebral ventricular anatomy and flow of cerebrospinal fluid, it has enormous potential to be adopted into student training in this field. With the digital age advancing rapidly, this has the potential to be used as an innovative tool alongside other methodologies for the training of future healthcare practitioners and scientists. This workflow could be used in the creation of other tools, which could be developed for use not only on desktop and laptop computers but also smartphones, tablets and fully immersive stereoscopic environments. It also could form the basis on which to build surgical simulations enhanced with haptic interaction.

Monoaxial external fixation of the calcaneus: an anatomical study assessing the safety of monoaxial pin insertion

The use of external fixation for intra-articular calcaneal fractures is increasing in popularity. Studies have shown fine wire and monoaxial external fixation to be a viable surgical alternative to more invasive methods of open reduction and internal fixation of the calcaneus. However, there is an absence of literature that quantifies the risk of pin insertion for monoaxial fixation. This study aimed to determine the safety of inserting monoaxial pins within the calcaneus to house the Orthofix Calcaneal Mini-Fixator. Five formalin embalmed cadaveric ankle and lower leg specimens were inserted with six monoaxial pins. Careful dissection then revealed the presence of the tendons of peroneus longus and brevis, the sural nerve and the small saphenous vein in relation to these pins. Measurements from each pin to each of these structures were made as the structures transected lines drawn from each pin to two palpable bony landmarks: the inferior tip of the lateral malleolus and the posterosuperior calcaneus. In doing this, the risk posed by each pin could be evaluated. We found that two particular pins, those used to hold the articular surface of the subtalar joint in a reduced position, posed a larger risk of injury to surrounding structures than the remaining pins. These findings therefore suggest that monoaxial fixation of the calcaneus using a six pin approach is a relatively safe method of rectifying calcaneal fractures and thus may serve as a welcome alternative to other methods of calcaneal fixation.

Circular frame fixation for calcaneal fractures risks injury to the medial neurovascular structures: a cadaveric description

AIM There is a risk of iatrogenic injury to the soft tissues of the calcaneus and this study assesses the risk of injury to these structures in circular frame calcaneal fracture fixation. MATERIALS AND METHODS After olive tip wires were inserted, an L-shaped incision on the lateral and medial aspects of 5 formalin fixed cadaveric feet was performed to expose the underlying soft tissues. The calcaneus was divided into zones corresponding to high, medium and low risk using a grading system. RESULTS Structures at high risk included the posterior tibial artery, posterior tibial vein and posterior tibial nerve on the medial aspect. Soft tissue structures on the lateral side that were shown to be at lower risk of injury were the small saphenous vein and the sural nerve and the tendons of fibularis longus and fibularis brevis. CONCLUSION The lateral surface of the calcaneus provides a lower risk area for external fixation. The risk of injury to significant soft tissues using a circular frame fixation approach has been shown to be greater on the medial aspect. CLINICAL RELEVANCE This study highlights the relevant anatomical relations in circular frame fixation for calcaneal fractures to minimise damage to these structures.

Acute fractures of the pediatric foot and ankle

BackgroundInjuries around the foot and ankle are challenging. There is a paucity of literature, outside that of specialist orthopedic journals, that focuses on this subject in the pediatric population.Data sourcesIn this review, we outline pediatric foot and ankle fractures in an anatomically oriented manner from the current literature. Our aim is to aid the emergency department doctor to manage these challenging injuries more effectively in the acute setting.ResultsThese injuries require a detailed history and examination to aid the diagnosis. Often, plain radiographs are sufficient, but more complex injuries require the use of magnetic resonance imaging. Treatment is dependent on the proximity to skeletal maturity and the degree of displacement of fracture. Children have a marked ability to remodel after fractures and therefore mainstay treatment is immobilization by a cast or splint. Operative fixation, although uncommon in this population, may be necessary with adolescents, certain unstable injuries or in cases with displaced articular surface. In the setting of severe foot trauma, skin compromise and compartment syndrome of the foot must be excluded.ConclusionThe integrity of the physis, articular surface and soft tissues are all equally important in treating these injuries.

Constructionist learning in anatomy education: what anatomy students can learn through serious games

In this paper we describe the use of 3D games technology in human anatomy education based on our MSc in Medical Visualisation and Human Anatomy teaching practice, i.e. students design and develop serious games for anatomy education using the Unity 3D game engine. Students are engaged in this process not only as consumers of serious games, but as authors and creators. The benefits of this constructionist learning approach are discussed. Five domains of learning are identified, in terms of what anatomy students, tutors, and final users (players) can learn through serious games and their development process. We also justify the 3D engine selected for serious game development and discuss main obstacles and challenges to the use of this constructionist approach to teach non-computing students. Finally, we recommend that the serious game construction approach can be adopted in other academic disciplines in higher education.

Canine neuroanatomy: Development of a 3D reconstruction and interactive application for undergraduate veterinary education

Current methods used to communicate and present the complex arrangement of vasculature related to the brain and spinal cord is limited in undergraduate veterinary neuroanatomy training. Traditionally it is taught with 2-dimensional (2D) diagrams, photographs and medical imaging scans which show a fixed viewpoint. 2D representations of 3-dimensional (3D) objects however lead to loss of spatial information, which can present problems when translating this to the patient. Computer-assisted learning packages with interactive 3D anatomical models have become established in medical training, yet equivalent resources are scarce in veterinary education. For this reason, we set out to develop a workflow methodology creating an interactive model depicting the vasculature of the canine brain that could be used in undergraduate education. Using MR images of a dog and several commonly available software programs, we set out to show how combining image editing, segmentation and surface generation, 3D modeling and texturing can result in the creation of a fully interactive application for veterinary training. In addition to clearly identifying a workflow methodology for the creation of this dataset, we have also demonstrated how an interactive tutorial and self-assessment tool can be incorporated into this. In conclusion, we present a workflow which has been successful in developing a 3D reconstruction of the canine brain and associated vasculature through segmentation, surface generation and post-processing of readily available medical imaging data. The reconstructed model was implemented into an interactive application for veterinary education that has been designed to target the problems associated with learning neuroanatomy, primarily the inability to visualise complex spatial arrangements from 2D resources. The lack of similar resources in this field suggests this workflow is original within a veterinary context. There is great potential to explore this method, and introduce a new dimension into veterinary education and training.