PelVis: Atlas-based Surgical Planning for Oncological Pelvic Surgery

Stem cells & developmental biolog

Pelvic lymphatic drainage pathways in relation to the autonomic nerves: implications for radical hysterectomy

Stem cells & developmental biolog

VarVis:visualizing anatomical variation in branching structures

Anatomical variations are naturally-occurring deviations from typical human anatomy. While these variations are considered normal and non-pathological, they are still of interest in clinical practice for medical specialists such as radiologists and transplantation surgeons. The complex variations in branching structures, for instance in arteries or nerves, are currently visualized side-by-side in illustrations or expressed using plain text in medical publications. In this work, we present a novel way of visualizing anatomical variations in complex branching structures for educational purposes: VarVis. VarVis consists of several linked views that reveal global and local similarities and differences in the variations. We propose a novel graph representation to provide an overview of the topological changes. Our solution involves a topolog-ical similarity measure, which allows the user to select variations at a global level based on their degree of similarity. After a selection is made, local topological differences can be interactively explored using illustrations and topology graphs. We also incorporate additional information regarding the probability of the various cases. Our solution has several advantages over traditional approaches, which we demonstrate in an evaluation

Model-based visualization for medical education and training

Anatomy, or the study of the structure of the human body, is an essential component of medical education. Certain parts of human anatomy are considered to be more complex to understand than others, due to a multitude of closely related structures. Furthermore, there are many potential variations in anatomy, e.g., different topologies of vessels, and knowledge of these variations is critical for many in medical practice. Some aspects of individual anatomy, such as the autonomic nerves, are not visible in individuals through medical imaging techniques or even during surgery, placing these nerves at risk for damage. 3D models and interactive visualization techniques can be used to improve understanding of this complex anatomy, in combination with traditional medical education paradigms. We present a framework incorporating several advanced medical visualization techniques and applications for teaching and training purposes, which is the result of an interdisciplinary project. In contrast to previous approaches which focus on general anatomy visualization or direct visualization of medical imaging data, we employ model-based techniques to represent variational anatomy, as well as anatomy not visible from imaging. Our framework covers the complete spectrum including general anatomy, anatomical variations, and anatomy in individual patients. Applications within our framework were evaluated positively with medical users, and our educational tool for general anatomy is in use in a Massive Open Online Course (MOOC) on anatomy, which had over 17000 participants worldwide in the first run

PelVis:atlas-based surgical planning for oncological pelvic surgery

\u3cp\u3eDue to the intricate relationship between the pelvic organs and vital structures, such as vessels and nerves, pelvic anatomy is often considered to be complex to comprehend. In oncological pelvic surgery, a trade-off has to be made between complete tumor resection and preserving function by preventing damage to the nerves. Damage to the autonomic nerves causes undesirable post-operative side-effects such as fecal and urinal incontinence, as well as sexual dysfunction in up to 80 percent of the cases. Since these autonomic nerves are not visible in pre-operative MRI scans or during surgery, avoiding nerve damage during such a surgical procedure becomes challenging. In this work, we present visualization methods to represent context, target, and risk structures for surgical planning. We employ distance-based and occlusion management techniques in an atlas-based surgical planning tool for oncological pelvic surgery. Patient-specific pre-operative MRI scans are registered to an atlas model that includes nerve information. Through several interactive linked views, the spatial relationships and distances between the organs, tumor and risk zones are visualized to improve understanding, while avoiding occlusion. In this way, the surgeon can examine surgically relevant structures and plan the procedure before going into the operating theater, thus raising awareness of the autonomic nerve zone regions and potentially reducing post-operative complications. Furthermore, we present the results of a domain expert evaluation with surgical oncologists that demonstrates the advantages of our approach.\u3c/p\u3

Lymphatic drainage pathways from the cervix uteri: implications for radical hysterectomy?

Radical hysterectomy with pelvic lymphadenectomy is the treatment of choice for early-stage cervical cancer. Wertheim's original technique has been often modified, mainly in the extent of parametrectomy. Okabayashi's technique is considered as the most radical variant regarding removal of the ventral parametrium and paracolpal tissues. Surgical outcome concerning recurrence and survival is good, but morbidity is high due to autonomic nerve damage. While the autonomic network has been studied extensively, the lymphatic system is less understood. This study describes the lymphatic drainage pathways of the cervix uteri and specifically the presence of lymphatics in the vesico-uterine ligament (VUL). A developmental series of 10 human female fetal pelves was studied. Paraffin embedded blocks were sliced in transverse sections of 8 or 10 μm. Analysis was performed by staining with antibodies against LYVE-1 (lymphatic endothelium), S100 (Schwann cells), alpha-Smooth Muscle Actin (smooth muscle cells) and CD68 (macrophages). The results were three-dimensionally represented. Two major pathways drained the cervix uteri: a supra-ureteral pathway, running in the cardinal ligament superior to the ureter, and a dorsal pathway, running in the utero-sacral ligament towards the rectal pillars. No lymph vessels draining the cervix uteri were detected in the VUL. In the paracolpal parametrium lymph vessels draining the upper vagina fused with those from the bladder. The VUL does not contain lymphatics from the cervix uteri. Hence, the favorable survival outcomes of the Okabayashi technique cannot be explained by radical removal of lymphatic pathways in the ventrocaudal parametriu

The development of a 3D anatomical atlas of the pelvis: Taking the next step in enhancing surgical anatomical education and clinical guidance

Stem cells & developmental biolog

The online anatomical human:anatomical knowledge exchange on the web

Human anatomy is complex and as early as the late bronze age, people have been trying to gain insights in the functioning of the human body. Nowadays, resources such as books and software are available to educate medical students, but these media usually have some restrictions; anatomical images in books present information from fixed views and do not allow readers to freely explore the information, while software tools often present an idealized average human anatomy.\u3cbr/\u3eIn this work, we introduce the Online Anatomical Human (OAH), an online viewer and annotation system for anatomical in- formation. It is based on real human anatomy and incorporates medical image data in linked 2D and 3D views. The goals of this anatomical online resource are two-fold. First of all, the OAH will serve as an educational platform available to anyone that has access to a modern web browser. Secondly, by making our work accessible to medical experts, we can ensure an increasing amount of information and, hereby, a gain in educational value of our tool

62. The virtual surgical pelvis:a highly-detailed 3D pelvic model for anatomical education and surgical simulation

Background: The surgical anatomy of the pelvis is highly complex. In case of rectal cancer the surgeon is challenged to perform a total mesorectal excision (TME) warranting complete removal of the tumor and preservation of the autonomic nerves. However, incomplete TME specimens and surgical damage to the nerves are still part of clinical reality. A highly-detailed 3D pelvic model would be an excellent tool to increase anatomical knowledge of the surgical anatomy of the pelvis. Visible Human Datasets (VHDs) are often used to create a 3D model, but they lack anatomical detail such as autonomic nerves and fasciae. Immunohistochemistry is an ideal method to study those key surgical structures at microscopic level. Recently, the Unified Anatomical Human (UAH) has been developed. UAH integrates heterogeneous anatomical data and will allow registration of patient-specific diagnostic images. In this study, we describe the development of The Virtual Surgical Pelvis (VSP) and its potential clinical value in anatomical education and surgical simulation. Material and methods: We selected 910 slices from a VHD that comprised the entire pelvis. All surgically relevant anatomical structures were manually segmented using Amira� software and three-dimensionally reconstructed using the UAH. The Online Anatomical Human (OAH), an online web-viewer, was developed as well. Paraffin embedded mega blocks of 1 female cadaveric pelvic exenteration specimen were sliced in transverse sections of 5 �m. A series was stained with Hematoxylin & Eosin and Masson�s Trichome and selected sections were immunohistochemically stained with S100, a pan-neuron marker. The autonomic nerves and fasciae were manually segmented in Amira� software, three-dimensionally reconstructed and integrated using the UAH. Results: Currently, the VSP presents most of the essential surgical anatomy of the pelvis, including the levator ani muscle and pudendal nerve, and can be interactively visualized in the UAH and OAH. Microscopic analysis of the female cadaveric specimen reveals the organization of autonomic nerves and fasciae in relation to pelvic organs. Conclusion: The VSP showing the complex pelvic anatomy is a potentially excellent tool for anatomical education. Registration of the VSP to patient-specific diagnostic images allows visualization of key surgical structures such as autonomic nerves and fasciae in relation to pelvic viscera. This makes surgical simulation a nearby future goal for all pelvic surgeons