The Result of Conservative Treatment of Proximal Humerus Fracture in Elderly Patients

PURPOSE: With the increase in the old age population, proximal humerus fractures have been increasing recently. However, complications after operative treatment, such as fixation failure, are common because of osteoporosis. We treated proximal humerus fractures in patients with osteoporosis conservatively, and evaluated the radiographic and functional results by analyzing the factors affecting the results. MATERIALS AND METHODS: Nineteen out of 30 cases for whom the clinical follow-up was over 1 year were included in this retrospective study. There were 17 females and 2 males, and the mean age was 73.2 years. The causes were slip from a short height (18 cases) and a minor car accident (1 case). We evaluated the union period, nonunion, malunion and the Constant score and analyzed several factors affecting the functional result, such as age, fracture pattern, and malunion. RESULTS: Seventeen cases (89.5%) obtained union within 12.8 weeks on average. Neck-shaft angle was 125.3degrees on average, with seven cases of malunion. The Constant score was 84.1 on average, and there were excellent scores in 11 cases, good scores in 4 cases, and fair scores in 2 cases. Fracture pattern, neck-shaft angle, or malunion did not affect the functional outcome, and elderly patients showed poorer shoulder function. CONCLUSION: Proximal humeral fractures with osteoporosis may achieve a high rate of bony union when treated with conservative methods. Despite the common occurrence of malunion, a satisfactory functional outcome may be expected.

Similar Degree in Mechanical Left Ventricular Dyssynchrony Between Right Ventricular Outflow Tract and Right Ventricular Apical Pacing: A Strain Doppler Imaging Study

BACKGROUND AND OBJECTIVES: Long-term right ventricular (RV) apex pacing has been associated with left ventricular (LV) systolic dysfunction. However, pacing in the RV outflow tract (RVOT) is associated with a narrower QRS duration and may have a more normal LV activation in comparison to RV apical (RVA) pacing. We hypothesized that RVOT pacing is associated with less mechanical dyssynchrony compared to RVA pacing and that it also more closely resembles mechanical activation in normal controls with a narrow QRS. SUBJECTS AND METHODS: We studied 9 patients with RV pacing, 9 with left bundle branch block (LBBB), and 15 normal controls with a narrow QRS. In the RV pacing group, we paced from the RVA and RVOT. At the end of each pacing train, we obtained echocardiographic images in the apical 4- and 2-chamber views and obtained the following parameters: the compression/expansion crossover point (CEP) for myocardial strain and the time from QRS onset to the CEP in the strain image. The degree of dyssynchrony was evaluated using the dispersion and standard deviation of CEP times in 12 segments of the LV. RESULTS: Significant dyssynchrony was observed in the RVOT pacing group compared to the group with normal QRS. No significant difference was observed in LV mechanical dyssynchrony among the RVOT pacing, RVA pacing, and LBBB groups. CONCLUSION: RVOT pacing is associated with significant LV dyssynchrony. Although the RVOT has been recommended as an alternative site for pacing, this approach may have adverse effects on long-term LV function.

FEM Analysis of the Effects of Mouth guard material properties on the Head and Brain under Mandibular Impact / 대한치과보철학회지

STATEMENT OF PROBLEM & PURPOSE: The purpose of this study was to investigate the effect of a mouth guard material properties on the skull and brain when they were under impact loads on mandible. MATERIAL AND METHODS: Two customized mouth protectors having different material propeerst ieach other were made for a female Korean who had no history of brain trauma, no cerebral diseases, nomal occlusion and natural dentition. The 3D finite element model of human skull and brain scanned by means of computed tomography was constructed. The FEM model of head was composed of 407,825 elements and 82,138 nodes, including skull, brain, maxilla, mandible, articular disc, teeth and mouth guard. The stress concentrations on maxillary teeth, maxilla and skull with two mouth guards were evaluated under oblique impact load of 800N onto mandibular 3 loading points for 0.1sec. And the brain relative displacement was compared in two different mouth guard materials under same condition. RESULT AND CONCLUSION: The results were as follows; 1. In comparison of von Mises stress on maxillary teeth, a soft mouth guard material had significantly lower stress values on measuring point than a hard mouth protector materials (P < .05). 2. In comparison of von Mises stress on maxilla and skull, A soft mouth protector material had significantly lower stress values on measuring point than a hard mouth protector materials (P < .05). 3. For impact loads on mandible, there were more stress concentrated area on maxilla and skull with hard mouth guard than soft with mouth protector. 4. For impact loads on mandible, brain relative displacement had little relation with mouth guard material properties. In results of this study, soft mouth guard materials were superior to hard mouth guard materials for mandible impact loads for prevention of sports injuries. Although the results of this study were not enough to figure out the roles of needed mouth guard material properties for a human head, we got some knowledge of the pattern about stress concentration and distribution on maxilla and skull for impact loads with soft or hard mouth protector. More studies are needed to substantiate the relationship between the mouth guard materials and sports injuries.

Surgical Repositioning of the Extruded Dento-alveolar Segments by the Single-Stage Posterior Maxillary Segmental Osteotomy