ABSTRACT
PURPOSE: There is still a clinical need to easily evaluate the metastatic status of lymph nodes during breast cancer surgery. We hypothesized that ex vivo shear-wave elastography (SWE) would predict precisely the presence of metastasis in the excised lymph nodes. METHODS: A total of 63 patients who underwent breast cancer surgery were prospectively enrolled in this study from May 2014 to April 2015. The excised axillary lymph nodes were examined using ex vivo SWE. Metastatic status was confirmed based on the final histopathological diagnosis of the permanent section. Lymph node characteristics and elasticity values measured by ex vivo SWE were assessed for possible association with nodal metastasis. RESULTS: A total of 274 lymph nodes, harvested from 63 patients, were examined using ex vivo SWE. The data obtained from 228 of these nodes from 55 patients were included in the analysis. Results showed that 187 lymph nodes (82.0%) were nonmetastatic and 41 lymph nodes (18.0%) were metastatic. There was significant difference between metastatic and nonmetastatic nodes with respect to the mean (45.4 kPa and 17.7 kPa, p<0.001) and maximum (55.3 kPa and 23.2 kPa, p<0.001) stiffness. The elasticity ratio was higher in the metastatic nodes (4.36 and 1.57, p<0.001). Metastatic nodes were significantly larger than nonmetastatic nodes (mean size, 10.5 mm and 7.5 mm, p<0.001). The size of metastatic nodes and nodal stiffness were correlated (correlation coefficient of mean stiffness, r=0.553). The area under curve of mean stiffness, maximum stiffness, and elasticity ratio were 0.794, 0.802, and 0.831, respectively. CONCLUSION: Ex vivo SWE may be a feasible method to predict axillary lymph node metastasis intraoperatively in patients undergoing breast cancer surgery.
Subject(s)
Humans , Area Under Curve , Axilla , Breast Neoplasms , Breast , Diagnosis , Elasticity , Elasticity Imaging Techniques , Lymph Nodes , Lymphatic Metastasis , Methods , Neoplasm Metastasis , Prospective StudiesABSTRACT
PURPOSE: Laparoscopic totally extraperitoneal (TEP) herniorrhaphy has been recognized as a treatment option for inguinal hernia. The objective of this study was to clarify the learning curve for laparoscopic TEP herniorrhaphy using the moving average method. METHODS: A total of 90 patients underwent laparoscopic TEP herniorrhaphy by a single surgeon between March 2009 and March 2011. We analyzed medical records including the demographic data, operating time, hospital stay, and postoperative complications. RESULTS: The mean operating time of the initial 30 cases (learning period group) was 66.3 minutes. After the initial 30 cases were performed, the time decreased to 52.8 minutes in the later 60 cases (experienced period group, P = 0.015). This represents the operating time becoming stabilized and then decreasing as the number of performed cases accumulates. Hospital stay was shorter and frequency of pain control, and complication rate were lower in the experienced period, however, there was no statistical significance. CONCLUSION: We suggest that number of patients needed for the learning curve for laparoscopic TEP herniorrhaphy should be 30 cases. The operating time for laparoscopic TEP herniorrhaphy stabilizes after 40 cases in moving average analysis.
Subject(s)
Humans , Hernia, Inguinal , Herniorrhaphy , Laparoscopy , Learning , Learning Curve , Length of Stay , Medical Records , PyrazinesABSTRACT
The purpose of the present study is to evaluate the stress distribution on the length and diameter of the miniscrew and cortical bone width. Three dimensional finite element models were made of diameter 1.2mm, 1.6mm, 2.0mm and length 6.0mm, 8.0mm, 10.0mm, 12.0mm and cortical bone width 1.0mm. Also, another three dimensional finite element models were made of diameter 1.2mm, 1.6mm, 2.0mm and length 8.0mm and cortical bone width 1.0mm, 1.5mm, 2.0mm, 2.5mm. Two-hundred grams horizontal force were applied on the center of the miniscrew head and at that stress distribution and its magnitude had been analyzed by ANSYS, which is three dimensional finite element analysis program. The obtained results were as follows : 1. The comparison of the maximum von-Mises stress in the miniscrew showed that as the diameter increases from 1.2mm to 2.0mm stress has been decreased, while on the same diameter stress was not changed regardless of the length change. 2. The comparison of the maximum von-Mises stress in the cortical and cancellous bone showed that as the diameter increases from 1.2mm to 2.0mm stress has been decreased, while on the same diameter stress was not changed regardless of the length change. 3. In the analysis of the stress distribution in the cortical and cancellous bone, the most of the stress had been absorbed in the cortical bone, and did not transmitted much to the cancellous bone. 4. In the analysis of the maximum von-Mises stress according to the cortical bone width, the same diameter of the miniscrew showed a constant stress value regardless of the cortical bone width change. The above results suggest that the maintenance of the miniscrew is more reliable on diameter than length of the miniscrew.