Identifying a Safe Range of Stimulation Current for Intraoperative Neuromonitoring of the Recurrent Laryngeal Nerve: Results from a Canine Model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) has been widely applied during thyroid surgery. However, the safe range of stimulation intensity for IONM remains undetermined.</p><p><b>METHODS</b>Total thyroidectomies were performed on twenty dogs, and their RLNs were stimulated with a current of 5-20 mA (step-wise in 5 mA increments) for 1 min. The evoked electromyography (EMG) of vocal muscles before and after supramaximal stimulation were recorded and compared. Acute microstructural morphological changes in the RLNs were observed immediately postoperatively under an electron microscope.</p><p><b>RESULTS</b>The average stimulating threshold for RLNs stimulated with 15 mA and 20 mA showed no significant changes compared to the unstimulated RLNs (15 mA group: 0.320 ± 0.123 mA vs. 0.315 ± 0.097 mA, P = 0.847; 20 mA group: 0.305 ± 0.101 mA vs. 0.300 ± 0.103 mA, P = 0.758). Similar outcomes were shown in average evoked EMG amplitude (15 mA group: 1,026 ± 268 μV vs. 1,021 ± 273 μV, P = 0.834; 20 mA group: 1,162 ± 275 μV vs. 1,200 ± 258 μV, P = 0.148). However, obvious acute microstructural morphological changes were observed in the nerves that were stimulated with 20 mA.</p><p><b>CONCLUSIONS</b>A stimulation intensity less than 15 mA might be safe for IONM of the RLN.</p>

Significant Differences in the Clinicopathological Characteristics and Survival of Gastric Cancer Patients from Two Cancer Centers in China and Korea

PURPOSE: To compare the clinicopathological data and long-term survival of gastric cancer patients in China and Korea. MATERIALS AND METHODS: Patients who had undergone gastrectomy for gastric cancer between 1998 and 2009 in 2 high-volume institutions in both China (n=1,637) and Korea (n=2,231) were retrospectively evaluated. Clinicopathological variables, overall survival (OS), progression-free survival (PFS), and surgery-related complications were assessed for all patients and compared between the 2 institutions. RESULTS: Chinese patients included in the study were significantly older and had a significantly lower body mass index (BMI) than the Korean patients. Esophagogastric junction tumors were more frequent in Chinese patients. However, the number of patients with stage I gastric cancer, the number of harvested lymph nodes, and the number of total gastrectomies were significantly higher in the Korean population. Korean patients also presented with fewer undifferentiated tumors than Chinese patients. Furthermore, Korean patients had prolonged OS and PFS for stage III cancers only. BMI, tumor-node-metastasis (TNM) stage, tumor invasion, number of positive lymph nodes, and distant metastases were all independent factors affecting OS and PFS. CONCLUSIONS: Although China and Korea are neighboring Asian countries, the clinicopathological characteristics of Chinese patients are significantly different from those of Korean patients. Korean gastric cancer patients had longer OS and PFS than Chinese patients. Influencing factors included TNM stage, tumor invasion, and lymph node metastasis.

Complete mesocolic excision versus traditional radical resection in colon cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To compare the short-term efficacy and safety between complete mesocolic excision (CME) and traditional radical resection in colon cancer.</p><p><b>METHODS</b>Between January 2008 and August 2011, 92 patients undergoing elective open surgery for colon were included in the study. CME was performed in 54 patients in the period from November 2009 to August 2011. The other 38 patients underwent traditional radical resection from January 2008 to October 2009. Short-term outcomes were compared between the patients of two different time periods.</p><p><b>RESULTS</b>Lymph nodes retrieved in the CME group (22.2 ± 8.0) were significant more than that in the control group (18.6 ± 4.7)(P<0.05). In patients with stage III cancer, CME group was associated with higher lymph node counts (23.8 ± 7.6 vs. 16.7 ± 3.6, P<0.01), however, there were no significant differences for those with stage I and stage II cancer (P>0.05). The number of positive lymph nodes and metastatic lymph node ratio (LNR) for stage III patients in two groups were not significantly different (P>0.05). There were no differences in operation time, time to first bowel movement, hospital stay, and postoperative complications between the two groups (P>0.05). However, intraoperative blood loss in the CME group was significantly reduced (median, 100 vs. 115 ml, P<0.05).</p><p><b>CONCLUSIONS</b>CME can achieve en-bloc resection of the tumor and mesocolon, and have optimal lymph nodes harvest. Despite wider resection extent with CME technique, the surgical risk and postoperative complications are not increased and the short-term efficacy is good.</p>

Learning curve of complete mesocolic excision for colon cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To evaluate the learning curve of complete mesocolic excision(CME) for colon cancer.</p><p><b>METHODS</b>Clinical data of 75 cases in whom CME was performed by a group of surgeons in the Department of Gastrointestinal Surgery, Peking University People's Hospital from November 2009 to June 2011 were reviewed. The patients were divided into three groups(groups A, B, C, 25 cases in each group) by operative chronologic sequence.</p><p><b>RESULTS</b>There were no significant differences in age, sex, preoperative staging, cancer location, operation history of abdomen, ASA among the three groups(P>0.05). The operative time in group A was (205.4 ± 53.2) min and decreased to (180.4 ± 29.7) min in group B and (169.8 ± 41.3) min in group C (P<0.05). The postoperative hospital stay decreased from (17.8 ± 10.9) d in group A to(12.9 ± 4.1) d in group B and(11.0 ± 3.5) d in group C(P<0.05). The postoperative complication rate decreased from 32%(8/25) in group A and 36%(9/25) to 8%(2/25) in group C. The specimen quality was superior in group C compared to group A (WEST grade C above were 20 and 11 respectively, P<0.05). There were no significant differences in intraoperative bleeding, time to first flatus, postoperative fasting time, number of retrieved lymph nodes among the three groups(P>0.05).</p><p><b>CONCLUSION</b>From the learning curve of CME, surgeons can learn CME skill after performing 25 cases.</p>

Feasibility of complete mesocolic excision in elderly patients with colon cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore the short-term outcomes and safety of complete mesocolic excision (CME) in elderly patients with colon cancer.</p><p><b>METHODS</b>The clinical pathological factors of 71 patients with colon cancer undergoing CME procedure by the same group of surgeons were analyzed retrospectively from November 2009 to February 2012. The elderly group(≥70 years) and the non-elderly group(<70 years) were compared regarding short-term outcomes and safety.</p><p><b>RESULTS</b>Similar extent of resection could be achieved in the elderly and non-elderly groups in terms of area of mesentery[(13 049±4332) vs. (13 163±4725) mm2, P=0.916], distance between the tumor and the high ligation site[(95±22) vs. (98±20) mm, P=0.516], distance between normal bowel and high ligation site [(130±25) vs. (128±25) mm, P=0.731], the length of colon [(262±60) vs. (245±49) mm, P=0.212], and lymph nodes retrieved(22.0±6.4 vs. 24.8±9.9, P=0.168). The mean operative time, intraoperative blood loss, postoperative complications, time to first flatus, time to first bowel movement, drainage removal time, diet resumption, drainage volume in three days after surgery, and hospital deaths showed no statistical significances(all P>0.05), while hospital stay and expenses of the elderly group were significantly increased(both P<0.01).</p><p><b>CONCLUSION</b>Elderly patients undergoing elective CME operation can achieve similar operative extent and lymph nodes harvest, and the surgical risk is not increased.</p>