Detection of articular perforations of the proximal humerus fracture using a mobile 3D image intensifier - a cadaver study.

BACKGROUND: The purpose of this study was to investigate the accuracy of perforation detection with multiplanar reconstructions using a mobile 3D image intensifier. METHODS: In 12 paired human humeri, K-wires perforating the subchondral bone and placed just below the cartilage level were directed toward five specific regions in the humeral head. Image acquisition was initiated by a fluoroscopy scan. Within a range of 90°, 45° external rotation (ER) and 45° internal rotation (IR). The number and percentage of detected perforating screws were grouped and analyzed. Furthermore, the fluoroscopic images were converted into multiplanar CT-like reconstructions. Each K-wire perforation was characterized as "detected" or "not detected". RESULTS: In the series of fluoroscopy images in the standard neutral position at 30° internal rotation, and 30° external rotation, the perforations of all K-wires (n = 56) were detected. Twenty-nine (51.8%) of them were detected in one AP view, 22 (39.3%) in two AP views, and five (8.9%) in three AP views. All K-wire perforations (100%, n = 56) were detected in multiplanar reconstructions. CONCLUSION: In order to reveal all of the intraoperative and postoperative screw perforations in a "five screw configuration", conventional AP images should be established in both the neutral positions (0°), at 30° internal rotation and 30° external rotation. Alternatively, the intraoperative 3D scan with multiplanar reconstructions enables a 100% rate of detection of the screw perforations.

Anatomic study of the vascular perfusion of the sternum and its clinical relevance in deep sternal wound infection.

Introduction: Deep sternal wound infections (DSWI) are a rare but devastating complication after median sternotomy. Minor perfusion in bone and soft tissue, especially after recruiting the internal mammary artery for bypass supports the development of wound infection and nonunion of the sternal bone. The aim of the study was the macroscopic and radiological presentation of the vascular system supplying the sternum, in particular the compensating blood supply routes in the event that the internal mammary artery is no longer available after use as a bypass vessel. Method: This anatomic study was carried out on the anterior chest wall of 7 specimens. The thorax plates of 7 specimens were analyzed macroscopically after microsurgical preparation. Different anatomic preparations were produced using different contrast or form-giving substances. Radiological analysis and three-dimensional reconstructions were performed to show alternative, collateral sternal vessel perfusion under estimation of the loss of the internal thoracic artery due to a bypass. Results: The length of the ITA (internal thoracic artery), measured from the beginning of the first rib to the division into the superior epigastric artery and musculophrenic artery, was an average of 16.3 cm. On average, 18.5 branches were delivered from each artery, 10 medially to the sternum supply, and 8 to the intercostal muscle. Conclusion: Our analysis gives an overview of the macroanatomic vessel system supplying the sternal bone, describing especially a common trunk deriving from the ITA and supplying multiple branches and playing an important role in building a collateral circulation of the sternum. For better evaluation, in vivo CT analysis with contrast media should be performed in patients prior to the operation and directly after the use of the double ITA to demonstrate the change in perfusion of the sternum. In the future, preconditioning of the sternum by coiling the deriving branches could become an option, although patient selection has to be improved and further analysis of the topic performed.

Implementation of clinical references for undergraduates in anatomy.

This study evaluates the implementation of clinical references in undergraduate medical education. For this purpose, images of typical diagnostic, intraoperative and clinical findings were integrated into two different teaching formats and adapted to the learning objectives of the Institute of Anatomy in Leipzig. Paper based questionnaires were used to evaluate the status quo (without clinical images) and the optimal time of implementation, as well as the benefit for the students of human medicine. Three test groups were drawn from two preclinical semesters (2014 and 2015). The first group in 2014 represents the control group, which did not have any image-supported clinical references but only defined learning objectives regarding the five exams in special anatomy. Primary implementation took place in the dissection course (second semester) as automatically running Power Point presentations while secondary implementation was during one of the five clinical seminars within the fourth semester. All groups were asked to evaluate the pros and cons through a self-developed paper-based questionnaire. The analysis was performed employing Microsoft Excel and SPSS. It has been demonstrated that most of the students welcome and appreciate the implementation of appropriate images as a valuable support in understanding clinical references. On the contrary, the dissection course did not seem to be the right time for this implementation. In keeping with previous studies, the important role of anatomy in medical education was outlined. A close collaboration between preclinical and clinical physicians concerning educational matters was presented. Considering these approaches, high-quality and sustainable education can be provided. Better patient care and education of young academics should be the motivation.

Human vagus nerve branching in the cervical region.

BACKGROUND: Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects. However, vagus nerve branching has not yet been described in the context of vagus nerve stimulation. MATERIALS AND METHODS: Branching of the cervical vagus nerve was investigated macroscopically in 35 body donors (66 cervical sides) in the carotid sheath. After X-ray imaging for determining the vertebral levels of cervical vagus nerve branching, samples were removed to confirm histologically the nerve and to calculate cervical vagus nerve diameters and cross-sections. RESULTS: Cervical vagus nerve branching was observed in 29% of all cases (26% unilaterally, 3% bilaterally) and proven histologically in all cases. Right-sided branching (22%) was more common than left-sided branching (12%) and occurred on the level of the fourth and fifth vertebra on the left and on the level of the second to fifth vertebra on the right side. Vagus nerves without branching were significantly larger than vagus nerves with branches, concerning their diameters (4.79 mm vs. 3.78 mm) and cross-sections (7.24 mm2 vs. 5.28 mm2). DISCUSSION: Cervical vagus nerve branching is considerably more frequent than described previously. The side-dependent differences of vagus nerve branching may be linked to the asymmetric effects of the vagus nerve. Cervical vagus nerve branching should be taken into account when identifying main trunk of the vagus nerve for implanting electrodes to minimize potential side effects or lacking therapeutic benefits of vagus nerve stimulation.

The arterial blood supply of the helical rim and the earlobe-based advancement flap (ELBAF): a new strategy for reconstructions of helical rim defects.

BACKGROUND: Several techniques are currently available for reconstruction of helical rim defects including Antia and Buch's technique. Some of these techniques produce unsatisfying aesthetic results or are time consuming or technically challenging. Herein, we present the earlobe-based advancement flap (ELBAF) technique and its anatomical basis for reconstruction of helical rim defects. METHODS: A case series of 13 patients with helical rim defects of up to 3.8 cm in length were reconstructed using the ELBAF technique solely or with additional procedures. Patients were followed for the occurrence of complications and evaluation of aesthetic results for up to 8 years. An anatomical assay that included cadaver dissection and anatomical corrosion technique was performed in order to support the ELBAF technique. RESULTS: Thirteen patients (68.5 ± 9 years, two females) with full-thickness helical rim defects of up to 3.8-cm length caused by basal cell carcinoma in 92.3% underwent reconstruction surgery using the ELBAF technique solely or with additional procedures. No complications related to the ELBAF technique were encountered during follow-up. Cadaver dissections demonstrated a consistent arterial blood supply emerging from the earlobe area, producing arteries that run circularly along the helical rim. CONCLUSIONS: Based on the axial vessel pattern, the ELBAF technique seems to be a useful strategy to reconstruct full-thickness helical defects of up to 3.8 cm in length. This procedure can be regarded as a valid addition to the ear reconstruction repertoire, which can be used alone or in combination with other established techniques. LEVEL OF EVIDENCE: Level 4, case series.

Comparison of modified Thiel embalming and ethanol-glycerin fixation in an anatomy environment: Potentials and limitations of two complementary techniques.

Thiel-fixed specimens have outstandingly lifelike visual and haptic properties. However, the original Thiel method is expensive and requires an elaborate setup. It is therefore of principal interest to modify the Thiel method in order to make it available to a broader user group. A modified Thiel embalming method will be described in detail and compared to ethanol-glycerin fixation with the help of illustrative examples. The visual properties, haptic properties, the usability for performing histological investigations, costs and potential health aspects will be considered. Tissues fixed with the modified Thiel technique gave results similar to the original method, providing more realistic visual and haptic properties than ethanol-glycerin embalming. However, Thiel fixation is significantly more expensive and requires more precautions to minimize potential health hazards than ethanol-glycerin-fixed tissues. In contrast to ethanol-glycerin-fixed specimens, the Thiel-fixed specimens are not suitable for histological investigations. Both modes of fixation are inappropriate for biomechanical testing. Modified Thiel embalming simplifies the availability of body donors with lifelike properties and has cost-saving advantages to the original technique. Thiel-embalmed body donors are ideally suited for clinical workshops but have restrictions for student dissection courses in facilities with limited storage space, air circulation or technical staff. Vice versa, ethanol-glycerin-fixed body donors are well suited for student dissection courses in such an environment but are limited in their use for clinical workshops. Modified Thiel embalming therefore ideally complements ethanol-glycerin fixation in order to provide customized solutions for clinical workshops and student dissection courses in a wide range of applications.

Ethanol-glycerin fixation with thymol conservation: a potential alternative to formaldehyde and phenol embalming.

Anatomical fixation and conservation are required to prevent specimens from undergoing autolysis and decomposition. While fixation is the primary arrest of the structures responsible for autolysis and decomposition, conservation preserves the state of fixation. Although commonly used, formaldehyde has been classified as carcinogenic to humans. For this reason, an adequate substitute was developed. Ethanol-glycerin fixation and thymol conservation are described and compared with formaldehyde and phenol in this technical report. The setup, tissue qualities, financial aspects, and health concerns of this method are discussed. Ethanol-glycerin fixation and thymol conservation provide outstanding haptic and optic tissue qualities. Typical formaldehyde and phenol effects, such as skin, airway, and eye irritation, as well as carcinogenic effects, can be circumvented by using ethanol-glycerin and thymol instead. Ethanol-glycerin fixation is more expensive than formaldehyde and requires an explosion-proof facility. However, the absence of health effects and its convincing tissue qualities balance these higher costs. Therefore, ethanol-glycerin fixation and thymol conservation provide a potential alternative and complement established fixation techniques. The use of carcinogenic formaldehyde and toxic phenol can be effectively restricted through the use of the described method.

Interactive versus reproductive learning, a comparison of medical school graduates with participants of a postgraduate CPD session.

AIMS: In order to develop the e-learning teaching material for medical professionals who are not physicians, we compared solution-based interactive and reading-based reproductive learning with regard to the increase of knowledge. Furthermore we tried to identify additional factors influencing learning. METHODS: We used a quasi-experimental double-stage study design with pre-test (point of time t(1)), intervention and post-test (point of time t(2)). The classification into three comparable groups was carried out according to the pre-test results. The interactive and reproductive group participated in the intervention but not the control group. All three groups consisted of graduates of medical schools (N=150) and more experienced physiotherapists during continuing training (N=66). The increase of knowledge was assessed by the post-test. The analysis of variance was the most important statistical tool. RESULTS: Interactive learning generated a higher increase of knowledge than reproductive learning but was more time consuming. The two groups which participated in the intervention obtained better results than the control group. The level of education and the prior knowledge also influenced the post-test results. CONCLUSION: We recommend combining interactive and reproductive approaches for designing the e-learning platform.

Comparative anatomical measurements of osseous structures in the ovine and human knee.

The ovine stifle has been increasingly used as a large animal model for the human knee. Still, comparative anatomical measurements of the knee in sheep and humans are missing. Thus, the purpose of this study was to describe and measure the osseous anatomy of the ovine stifle in comparison to the human knee. Twenty-four stifles of skeletal-mature merino-sheep and 24 human cadaver knees were obtained and distances between selected anatomical structures of the distal femur, the proximal tibia, and the patella were measured digitally and documented. Based on these, intercondylar ratio, tibial aspect ratio, patella aspect ratio and the cortical index were calculated. Regarding epicondylar width, lateral condylar width, medial condylar width and the tibial dimensions, the ovine stifle can be considered as a human knee scaled down by one third. However, sheep have a smaller trochlear width and a narrower femoral intercondylar notch than humans resulting in lower relative values for intercondylar width and intercondylar height. The distal femur's cortical index is the same in both species. In contrast, sheep have a massive bone stock below their tibial plateau and a proximal tibial shaft with remarkably thick cortical bone. The ovine stifle can be regarded as a useful model for the human knee. However, future studies should consider the differences in the femoral intercondylar notch width, the patellofemoral joint's biomechanics and the proximal tibia's cortical bone stock.