Anterior Cruciate Ligament Stability in Soft-Embalmed Cadaver vs In vivo Knee: Alternative Approaches to Medical Education.

Introduction: Soft-embalmed cadavers have been used in medical education with a variety of success in different curriculum objectives. In the United States, the ACL is the most commonly injured ligament. Yet, there has been little focus on the stability of the knee in the sagittal plane provided by the anterior cruciate ligament within the soft-embalmed cadaver model. If the soft-embalmed cadaver ligaments contain similar elastic properties as an in-vivo knees, this will offer yet another means for further advancements in medical education to detect and assess musculoskeletal injuries. Purpose: Evaluate how similarly the anterior tibial translation of soft-embalmed cadaver anterior cruciate ligaments compares to in-vivo tissue. Methods: The KT-1000 arthrometer was used to assess the laxity of the anterior cruciate ligament of thirteen soft-embalmed cadavers consisting of five females and eight males with a mean age of 79.3 years and duration of time since embalming ranging from 250 to 1156 days. Anterior displacement of the tibia in relation to the femur was registered at 67N and 89N. The soft-embalmed cadaver measurements were compared against twenty-one healthy uninjured individuals whose anterior tibial translation was measured using the same process. Data sets were analyzed using a welch two-sample t-test to determine the similarity between the means of the data sets. Results: The t-tests proved a significant difference between live and soft-embalmed cadaver knees. The anterior tibial translation in the set of healthy live knees directly compared to the soft-embalmed cadaver group for 67N depicts an average difference of 1.76mm. The same comparison at 89N depicts an average difference of 2.12mm. Conclusion: While soft-embalmed cadavers may not directly replicate ATT to an exact number to that of in vivo tissue, they still allow the perception of the tibial translation against a stationary femur. The difference is less than 2.5 mm in both data sets when compared to an in-vivo knee, equivalent to one-tenth of an inch. Suggesting the viability of soft-embalmed cadavers ATT and should not exclude their use in medical education.

Bringing Physical Exam Skills Back from the Dead.

Physical examination education begins early for medical learners. A hindrance to physical exam competency is lack of exposure to pathology in standardized patient settings. This research focuses on improving medical education through the utilization of cadavers that have undergone a soft-embalming technique: the Thiel method. Three scenarios were created in four Thiel cadavers: anterior cruciate ligament (ACL) tear, posterior cruciate ligament (PCL) tear, and sham incision. Students were asked to diagnose ACL tears using the Lachman exam. A total of 54 learners participated in the study. Post-surveys indicated most learners: (1) prefer to use standardized patients (SPs) and soft-embalmed cadavers in their physical examination courses, (2) increased their confidence in performing the Lachman exam on real patients, and (3) enhanced their Lachman technique. SPs ultimately cannot volitionally reproduce the physical exam findings of ACL deficiency. Consequently, learners cannot accurately identify positive versus negative examination findings. Thiel-embalmed cadavers are a valuable resource for physical examination education. (Journal of Surgical Orthopaedic Advances 30(2):112-115, 2021).

Neurocristopathies: Enigmatic Appearances of Neural Crest Cell-derived Abnormalities.

The neural crest is an important transient structure that develops during embryogenesis in vertebrates. Neural crest cells are multipotent progenitor cells that migrate and develop into a diverse range of cells and tissues throughout the body. Although neural crest cells originate from the ectoderm, they can differentiate into mesodermal-type or endodermal-type cells and tissues. Some of these tissues include the peripheral, autonomic, and enteric nervous systems; chromaffin cells of the adrenal medulla; smooth muscles of the intracranial blood vessels; melanocytes of the skin; cartilage and bones of the face; and parafollicular cells of the thyroid gland. Neurocristopathies are a group of diseases caused by the abnormal generation, migration, or differentiation of neural crest cells. They often involve multiple organ systems in a single person, are often familial, and can be associated with the development of neoplasms. As understanding of the neural crest has advanced, many seemingly disparate diseases, such Treacher Collins syndrome, 22q11.2 deletion syndrome, Hirschsprung disease, neuroblastoma, neurocutaneous melanocytosis, and neurofibromatosis, have come to be recognized as neurocristopathies. Neurocristopathies can be divided into three main categories: dysgenetic malformations, neoplasms, and combined dysgenetic and neoplastic syndromes. In this article, neural crest development, as well as several associated dysgenetic, neoplastic, and combined neurocristopathies, are reviewed. Neurocristopathies often have clinical manifestations in multiple organ systems, and radiologists are positioned to have significant roles in the initial diagnosis of these disorders, evaluation of subclinical associated lesions, creation of treatment plans, and patient follow-up. Online supplemental material is available for this article. ©RSNA, 2019.