Background There have been arguments over the efficacy of elective unilateral central neck dissection (CND) in patients with papillary thyroid carcinoma (PTC) <1 cm who underwent hemithyroidectomy. This study was designed to investigate locoregional recurrence and postoperative complications related to elective unilateral CND for papillary thyroid microcarcinoma (PTMC). Methods Five hundred thirty‐seven patients who underwent hemithyroidectomy, with or without CND for PTMC, were included. We compared locoregional recurrence and postoperative complication rates between 138 patients who underwent hemithyroidectomy only (CND group) and 399 patients who underwent hemithyroidectomy with elective unilateral CND (CND+ group). Results Recurrence was observed in 32 patients. Twenty‐two patients with recurrence were in the CND+ group and 10 were in the CND‐ group. Recurrence rate was not significantly different between the 2 groups (P = .434). Conclusion Concomitant unilateral elective CND did not enhance outcomes of hemithyroidectomy for the treatment of PTMC.

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Reactor coolant pump (RCP) is designed for the heat transfer of heat which is generated from reactor vessel to steam generators by circulating the coolant water. RCP is the only rotating equipment in the nuclear steam supply system (NSSS). Therefore, the problem of vibration has arisen caused by the hydraulic forces of the working fluid. These forces can drastically alter the critical speeds and stability characteristics and can act as significant destabilizing forces. So, vibration evaluation of RCP has been considered as a very important issue [1]. Among them, unbalance response caused by weight of unbalancing of rotating shaft could have serious effects on the entire rotor system. Thus, precise unbalance response spectrum analyses are required. In general, in order to evaluate the unbalance response characteristics for centrifugal pump, finite element analysis was performed according to the ISO 1940-1 standard. However, finite element analysis according to the ISO 1940-1 standard does not considering fluid flow effect. So, finite element analysis result and experimental results may be some differences. Vibration characteristics of RCP has affected by fluid flow effect induced from working fluid. Therefore, in order to understand vibration characteristics for the RCP shaft assembly considered in actual operating condition, rotor dynamic analysis should be performed considering the fluid flow effect. In this research, owing to accurately evaluate the vibration characteristics for the RCP considering hydro forces due to the fluid flow, we measured the bearing force and moment take into account the fluid-induced force. And then response spectrum analysis of RCP shaft assembly was performed considering fluid induced bearing radial forces which are measured values. Lastly, evaluate the vibration characteristics considering effect of fluid flow according to the number of revolution.

Background and Objectives To find more accurate way to determine the location of parotid tumors that cross anatomical criteria for the facial nerve (FN). Subjects and Method Two hundred patients were included in the study and retrospectively studied. Five anatomical criteria were used to predict the location of parotid tumors on computed tomography (CT). Deep portion of tumors was measured and then, cutoff value was obtained after receiver operator curve analysis. The location of tumor was predicted by using the cutoff value and by the conventional way, in which the side where most of the tumor is located is determined as the tumor site. Results The parotid tumors were located in superficial lobes in 148 cases, and in deep lobes in 52 cases by operative record. The tumors that cross the anatomical criteria were defined as 'crossing tumor.' The cutoff values for prediction of 'crossing tumor' location on CT were 6.7 mm for anatomical line, 6.4 mm for FN line, 11.2 mm for retromandibular vein, 4.9 mm for Utrecht line and 3.8 mm for Conn's arc. The accuracy of 5 anatomical criteria for 'crossing tumor' was between 55.9% and 81.6% when the cutoff value was used, whereas the accuracy was between 25.7% and 68.9% when conventional way was used. Conclusion In cases of 'crossing tumor,' the cutoff value obtained by measurement of deep portion of tumor can be applied to improve the diagnostic performance for the prediction of tumor location.

Background and ObjectivesZZOne of the common complications after parotidectomy is a decrease in skin sensation around the parotid gland. This is known to be associated with damage to the great auricular nerve (GAN). The purpose of this study was to investigate the pattern of tactile sensory recovery after parotidectomy and the difference in sensory recovery according to the preservation or sacrifice of the GAN. Subjects and MethodZZFifty-two patients who underwent parotidectomy were enrolled in this study. The Touch Test Sensory Evaluator was used to measure the minimum tactile threshold value at 6 sites around the auricle before surgery and at 1 week, 1, 3, 6 and 12 months after surgery. ResultsZZThe tactile threshold was the highest at 1 month after parotidectomy in all 6 sites. After 1 month, the threshold value gradually decreased until 12 months after surgery. However, the threshold was not completely recovered to the preoperative threshold level. At least one branch and the main trunk of GAN were preserved in 39 patients; one of GAN branches was preserved but the main trunk of GAN was partially injured in 3 patients, and the main trunk of GAN was completely injured in 10 patients. The tactile sensory recovery showed no significant differences in relation to the GAN status. ConclusionZZThe tactile sensory value kept decreasing up to one month following parotidectomy and then gradually recovered. However, the tactile sensory did not recover completely even one year after surgery. The GAN preservation did not affect tactile sensory recovery.