Background: In bone sarcomas, chemotherapy has improved the prognosis with advances in diagnostic and surgical technologies, which has led to attempts to save limbs. As early detection and multidisciplinary treatment have improved the survival rate, curative surgery is considered for selected patients with metastatic bone carcinomas. Limb salvage procedures may vary in relation to the reconstruction method, which is accompanied by different complications. To overcome them, we devised a novel concept, insitu local tumor ablation and recycling machine based on radiofrequency (RF)-induced heating and intended experiments to demonstrate its feasibility. Methods: The fresh femurs of 6-month-old pigs were used after removing the epiphyses; the distal parts were placed in a heating chamber. Fiber-optic temperature sensors were inserted in the metaphysis, meta-diaphysis, and diaphysis. Temperatures were measured six times each during heating at 27.12 MHz at various powers. Additionally, the compressive and bending stiffnesses were measured six times each for the unprocessed, RF-treated, and pasteurized bones, and the results were compared. Results: Under 200 W power output, the temperatures at all measurement sites reached 70 °C or higher in 6 minutes, and the temperatures were maintained. The median compressive stiffness of RF-heated bones was 79.2% higher than that of pasteurized bones, but the difference was statistically insignificant. The median bending stiffness of RF-heated bones was approximately 66.3% of that of unprocessed bones, which was 20% higher than that of pasteurized bones. Conclusions The feasibility to rapidly attain and maintain temperatures for tumor ablation is shown, which favorably preserves bone stiffness through the in-situ local tumor ablation and recycling based on RF heating. The problem of nonuniform temperature distribution might be solved by an optimal design determined from simulation research and additional experiments.

Background: Compared to the classic open technique, limited exposure techniques have the advantages of less scar pain, more grip and pinch strength, and earlier return to daily life. We evaluated the effectiveness and safety of our novel method of minimally invasive carpal tunnel release using a hook knife through a small transverse carpal incision. Methods: This study included 111 carpal tunnel decompressions in 78 patients who underwent carpal tunnel release from January 2017 to December 2018. We performed carpal tunnel release using a hook knife through a small transverse incision just proximal to the wrist crease under local infiltration of lidocaine with tourniquet inflation in the upper arm. All patients were tolerable during the procedure and discharged following the procedure on the same day. Results: At an average of 29.4 months of follow-up (range, 12–51 months), all but one patient (99%) revealed complete or near complete symptomatic recovery. The average of the symptom severity score on the Boston questionnaire was 1.31 ± 0.30 and the average of the functional status score was 1.19 ± 0.26. The final mean Quick Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH) score was 8.66 (range, 2–39). There was no superficial palmar arch injury or nerve injury of the palmar cutaneous branch, recurrent motor branch, or median nerve itself as a complication of the procedure. No patient showed any wound infection or wound dehiscence. Conclusions Our carpal tunnel release using a hook knife through a small transverse carpal incision performed by an experienced surgeon is a safe and reliable method that is expected to have the benefits of simplicity and minimal invasiveness.

Schwannomas are benign, slow-growing peripheral nerve sheath tumors commonly occurring in the head, neck, and flexor regions of the extremities. Although most schwannomas are easily diagnosable, their variable morphology can occasionally create difficulty in diagnosis. Reporting pathologists should be aware that schwannomas can exhibit a broad spectrum of morphological patterns. Clinical and radiological examinations can show correlation and should be performed, in conjunction with ancillary tests, when appropriate. Furthermore, deferring a definitive diagnosis until excision may be necessary for small biopsy specimens and frozen sections. This report underscores these challenges through examination of two unique schwannoma cases, one predominantly cellular and the other myxoid, both of which posed significant challenges in histological interpretation.

Background: While low-cost, small-scale, desktop three-dimensional (3D) printers are gaining popularity in the education sector, some studies have reported harmful emissions of particles and volatile organic compounds during the fused deposition modeling (FDM) process, posing a potential health risk. Sarcomas are rare tumors, constituting a group of diverse rare malignant tumors. While some genetic and environmental factors contribute to the development of sarcomas, most cases are idiopathic and sporadic. Methods: We secured the medical records and statements about work environment from teachers diagnosed with sarcomas after frequent use of 3D printers in high schools, reviewed the cases, and described them in narrative format. Furthermore, popularization of FDM 3D printers, worrisome emissions released during the printing process, and related precautions and countermeasures were discussed through literature review. Results: Exceptionally, the cases of sarcomas, such as Ewing’s sarcoma, malignant peripheral nerve sheath tumor, and well-differentiated liposarcoma, arose in a common specific condition. All the teachers regularly operated 3D printers in poorly ventilated spaces for at least 2 years. They had no past or family history of relevant diseases. Conclusions We first reported three cases of sarcoma in teachers who used 3D printers in poorly ventilated conditions. Although a relationship between the use of 3D printers and the development of sarcomas has not been determined yet, it is important to come up with measures to protect teachers and students using 3D printers from the potential hazard.

Purpose: To determine the value of 3 Tesla (T) MRI texture analysis for predicting tumor margin infiltration in soft tissue sarcomas. Materials and Methods: Thirty-one patients who underwent 3T MRI and had a pathologically confirmed diagnosis of soft tissue sarcoma were included in this study. Margin infiltration on pathology was used as the gold standard. Texture analysis of soft tissue sarcomas was performed on axial T1-weighted images (WI) and T2WI, fat-suppressed contrast-enhanced (CE) T1WI, diffusion-weighted images (DWI) with b-value of 800 s/mm², and apparent diffusion coefficient (ADC) was mapped. Quantitative parameters were compared between sarcomas with infiltrative margins and those with circumscribed margins. Results: Among the 31 patients with soft tissue sarcomas, 23 showed tumor margin infiltration on pathology. There were significant differences in kurtosis with the spatial scaling factor (SSF) of 0 and 6 on T1WI, kurtosis (SSF, 0) on CE-T1WI, skewness (SSF, 0) on DWI, and skewness (SSF, 2, 4) on ADC between sarcomas with infiltrative margins and those with circumscribed margins (p ≤ 0.046). The area under the receiver operating characteristic curve based on MR texture features for identification of infiltrative tumor margins was 0.951 (p < 0.001). Conclusion MR texture analysis is reliable and accurate for the prediction of infiltrative margins of soft tissue sarcomas.

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Purpose: To investigate the value of MR textural analysis, including use of diffusionweighted imaging (DWI) to differentiate malignant from benign soft-tissue tumors on 3T MRI. Materials and Methods: We enrolled 69 patients (25 men, 44 women, ages 18 to 84 years) with pathologically confirmed soft-tissue tumors (29 benign, 40 malignant) who underwent pre-treatment 3T-MRI. We calculated MR texture, including mean, standard deviation (SD), skewness, kurtosis, mean of positive pixels (MPP), and entropy, according to different spatial-scale factors (SSF, 0, 2, 4, 6) on axial T1-and T2-weighted images (T1WI, T2WI), contrast-enhanced T1WI (CE-T1WI), high b-value DWI (800 sec/mm2 ), and apparent diffusion coefficient (ADC) map. We used the Mann-Whitney U test, logistic regression, and area under the receiver operating characteristic curve (AUC) for statistical analysis. Results: Malignant soft-tissue tumors had significantly lower mean values of DWI, ADC, T2WI and CE-T1WI, MPP of ADC, and CE-T1WI, but significantly higher kurtosis of DWI, T1WI, and CE-T1WI, and entropy of DWI, ADC, and T2WI than did benign tumors (P < 0.050). In multivariate logistic regression, the mean ADC value (SSF, 6) and kurtosis of CE-T1WI (SSF, 4) were independently associated with malignancy (P ≤ 0.009). A multivariate model of MR features worked well for diagnosis of malignant soft-tissue tumors (AUC, 0.909). Conclusion Accurate diagnosis could be obtained using MR textural analysis with DWI and CE-T1WI in differentiating benign from malignant soft-tissue tumors.

BACKGROUND: Decellularized nerve allografting is one of promising treatment options for nerve defect. As an effort to develop more efficient nerve graft, recently we have developed a new decellularization method for nerve allograft. The aim of this study was to evaluate the effectiveness and biocompatibility of nerve graft decellularized by our newly developed method. METHODS: Forty-eight inbred male Lewis rats were divided into two groups, Group I (autograft group, n = 25), Group II (decellularized isograft group, n = 23). Decellularized nerve grafts were prepared with our newly developed methods using amphoteric detergent and nuclease treatment. Serum cytokine level measurements at 0, 2, and 4 weeks and histologic evaluation for inflammatory cell infiltration at 6 and 16 weeks after nerve graft. RESULTS: There was no significant difference in mean maximum isometric tetanic force and weight of tibialis anterior muscle or ankle angle at toe-off phase between two groups at 6 and 16 weeks survival time points (p > 0.05). There was no inflammatory cell infiltration in either group and histomorphometric assessments of 6- and 16-week specimens of the isograft group did not differ from those in the autograft group with regard to number of fascicle, cross sectional area, fascicle area ratio, and number of regenerated nerve cells. CONCLUSION Based on inflammatory reaction, axonal regeneration, and functional outcomes, our newly developed decellularized nerve grafts were fairly biocompatible and had comparable effectiveness to autografts for nerve regeneration, which suggested it would be suitable for nerve reconstruction as an alternative to autograft.

BACKGROUND: Decellularized nerve allografting is one of promising treatment options for nerve defect. As an effort to develop more efficient nerve graft, recently we have developed a new decellularization method for nerve allograft. The aim of this study was to evaluate the effectiveness and biocompatibility of nerve graft decellularized by our newly developed method. METHODS: Forty-eight inbred male Lewis rats were divided into two groups, Group I (autograft group, n = 25), Group II (decellularized isograft group, n = 23). Decellularized nerve grafts were prepared with our newly developed methods using amphoteric detergent and nuclease treatment. Serum cytokine level measurements at 0, 2, and 4 weeks and histologic evaluation for inflammatory cell infiltration at 6 and 16 weeks after nerve graft. RESULTS: There was no significant difference in mean maximum isometric tetanic force and weight of tibialis anterior muscle or ankle angle at toe-off phase between two groups at 6 and 16 weeks survival time points (p > 0.05). There was no inflammatory cell infiltration in either group and histomorphometric assessments of 6- and 16-week specimens of the isograft group did not differ from those in the autograft group with regard to number of fascicle, cross sectional area, fascicle area ratio, and number of regenerated nerve cells. CONCLUSION Based on inflammatory reaction, axonal regeneration, and functional outcomes, our newly developed decellularized nerve grafts were fairly biocompatible and had comparable effectiveness to autografts for nerve regeneration, which suggested it would be suitable for nerve reconstruction as an alternative to autograft.

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.