More harm than good? The anatomy of misguided shielding of the ovaries.
Integrating carthage-specific T1rho MRI into knee clinic diagnostic imaging.
(26/113)With a rise in post-traumatic osteoarthritis, OA no longer is considered just a disease of aging. The 'gold standard' for OA diagnosis has long been planar radiographs for visualizing osteophytes, joint space narrowing and sclerotic changes. A typical magnetic resonance imaging (MRI) protocol will acquire proton density, T1, T2, and fat suppressed images that give a comprehensive picture of morphologic changes associated with injury and subsequent degenerative processes. However, the earliest events of cartilage degeneration occur within the tissue, before measureable changes in morphology. MRI methods have been proposed to display and quantify changes in composition and integrity of such elements of cartilage extracellular matrix as collagen and proteoglycan (PG) content in vivo. T1rho the spin-lattice relaxation time in the rotating frame, has come to the forefront for visualizing water proton-PG interactions in articular cartilage. The purpose of this T1rho MRI study was to define an objective femoral condyle-specific registration method, in which zone-dependent cartilage compositional changes could be assessed from the bone outward through the existing cartilage, at pre-ACL reconstruction and subsequent follow-up times, when the loss of thickness to surface-down cartilage erosion might occur later in the OA pathogenesis. Additionally, this study explores the effects of reducing the number of spin-lock times on the absolute T1rho relaxation times; a major parameter in expanding T1rho coverage to the whole joint while satisfying clinical imaging time and specific absorption rate (SAR) safety constraints. The developed image analysis tools serve as the first step toward quantitative functional assessment of cartilage health with noninvasive T1rho MRI, which has the potential to become an important new tool for the early diagnosis of cartilage degeneration following ACL trauma. (+info)
The course of the distal saphenous nerve: a cadaveric investigation and clinical implications.
(27/113)INTRODUCTION: Injury to the saphenous nerve at the ankle has been described as a complication resulting from incision and dissection over the distal tibia and medial malleolus. However, the exact course and location of the distal saphenous nerve is not well described in the literature. The purpose of this study was to determine the distal limit of the saphenous nerve and its anatomic relationship to commonly identified orthopaedic landmarks and surgical incisions. METHODS: Sixteen cadaveric ankles were examined at the level of the distal tibia medial malleolus. An incision was made along the medial aspect of the lower extremity from the knee to the hallux to follow the course and branches of the saphenous nerve under direct visualization. We recorded the shortest distance from the most distal visualized portion of the saphenous nerve to the tip of the medial malleolus, to the antero-medial arthroscopic portal site, and to the tibialis anterior tendon. RESULTS: The saphenous nerve runs posterior to the greater saphenous vein in the leg and divides into an anterior and posterior branch approximately 3 cm proximal to the tip of the medial malleolus. These branches terminate in the integument proximal to the tip of the medial malleolus, while the vein continues into the foot. The anterior branch ends at the anterior aspect of the medial malleolus near the posterior edge of the greater saphenous vein. The posterior branch ends near the posterior aspect of the medial malleolus. The average distance from the distal-most visualized aspect of the saphenous nerve to the tip of the medial malleolus measured 8mm +/-; 5mm; from the nerve to the medial arthroscopic portal measured 14mm +/-2mm; and from the nerve to the tibialis anterior measured 16mm +/-3mm. In only one case (of 16) was there an identifiable branch of the saphenous nerve extending to the foot and in this specimen it extended to the first metatarsophalangeal joint. The first metatarsophalangeal joint was innervated by the superficial peroneal nerve in all cases. Small variations were also noted. DISCUSSION AND CONCLUSIONS: This study highlights the proximity of the distal saphenous nerve to common landmarks in orthopaedic surgery. This has important clinical implications in ankle arthroscopy, tarsal tunnel syndrome, fixation of distal tibia medial malleolar fractures, and other procedures centered about the medial malleolus. While the distal course of the saphenous nerve is generally predictable, variations exist and thus the orthopaedic surgeon must operate cautiously to prevent iatrogenic injury. To avoid saphenous nerve injury, incisions should stay distal to the tip of the medial malleolus. The medial arthroscopic portal should be more than one centimeter from the anterior aspect of the medial malleolus which will also avoid the greater saphenous vein. Incision over the anterior tibialis tendon should stay within one centimeter of the medial edge of the tendon. (+info)
Anatomical factors involved in difficult cardiac resynchronization therapy procedure: a non-invasive study using dual-source 64-multi-slice computed tomography.
Inadvertent identification of the left pericardiophrenic vein following laser lead extraction to guide left ventricular lead placement.
Faces in 4 dimensions: Why do we care, and why the fourth dimension?
The reliability and reproducibility of cephalometric measurements: a comparison of conventional and digital methods.
Digital live-tracking 3-dimensional minisensors for recording head orientation during image acquisition.