Background: Radiofrequency thermal rhizotomy demonstrates an excellent treatment outcome with a high success rate among patients of intractable trigeminal neuralgia. The triangular plexus which is an immediate retrogasserian portion of the trigeminal root is suggested as the best place of lesioning during radiofrequency thermal rhizotomy. However, the anatomy of the triangular plexus has been relatively unrecognized, while the anatomical study related to therapeutic procedure is scarce. Objective: The purpose of this study is to confirm with gross and microscopic finding of the trigeminal system whether, if an electrode tip is placed on the petroclival junction in lateral cranial view, it actually arrives at the triangular plexus or not. In relation to therapeutic procedure, we examined the triangular plexus with morphological and histological methods. Study Design: Human cadaveric study. Setting: An anatomical laboratory in South Korea. Methods: Percutaneous procedure of radiofrequency thermal rhizotomy under C-arm guidance was performed in 8 cadavers. Final target of the electrode tip was the petroclival junction under true lateral cranial view. The location of the electrode tip was determined under observation of the presence of an injected dye. Triangular plexus size was measured grossly and microscopically. Gross and microscopic evaluation of the triangular plexus was performed. Results: Among 15 trigeminal systems, 8 showed dye appearance in the triangular plexus, while 6 showed it in the trigeminal ganglion. Overall, 53% of radiofrequency thermal rhizotomy could reach the triangular plexus when an electrode tip was placed on the petroclival junction. The grossly measured average triangular plexus vertical and transverse diameters were 0.8 cm and 1.3 cm, respectively. Limitation: Only radiologic landmark was used to confirm the location of the electrode tip. However, further study confirming the location of the electrode tip under the guidance of electrical stimulation is needed. Conclusion: When an electrode tip was placed on the petroclival junction, 53% of radiofrequency thermal rhizotomy could reach the triangular plexus. Key words: Petroclival junction, trigeminal neuralgia, triangular plexus, radiofrequency thermal rhizotomy

BackgroundUsing analysis of air samples from the workplace, we report on one case of pneumoconiosis in an individual who has been working in a polytetrafluoroethylene (PTFE) spraying process for 28 years.Case presentationThe patient was diagnosed with granulomatous lung disease caused by PTFE using computed tomography (CT), lung biopsy and electron microscopy. To assess the qualitative and quantitative exposure to PTFE in workplace, Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA) were performed on air samples from the workplace. The presence of PTFE particles was confirmed, and the airborne concentration of PTFE was estimated to be 0.75 mg/m3.ConclusionsThis case demonstrates that long-term exposure to PTFE spraying can cause granulomatous lung lesions such as pneumoconiosis; such lesions appear to be caused not by the degradation products of PTFE from high temperatures but by spraying the particles of PTFE. Along with air-sampling analysis, we suggest monitoring the concentration of airborne PTFE particles related to chronic lung disease.

(1) Background: Differential diagnosis using immunohistochemistry (IHC) panels is a crucial step in the pathological diagnosis of hematolymphoid neoplasms. In this study, we evaluated the prediction accuracy of the ImmunoGenius software using nationwide data to validate its clinical utility. (2) Methods: We collected pathologically confirmed lymphoid neoplasms and their corresponding IHC results from 25 major university hospitals in Korea between 2015 and 2016. We tested ImmunoGenius using these real IHC panel data and compared the precision hit rate with previously reported diagnoses. (3) Results: We enrolled 3052 cases of lymphoid neoplasms with an average of 8.3 IHC results. The precision hit rate was 84.5% for these cases, whereas it was 95.0% for 984 in-house cases. (4) Discussion: ImmunoGenius showed excellent results in most B-cell lymphomas and generally showed equivalent performance in T-cell lymphomas. The primary reasons for inaccurate precision were atypical IHC profiles of certain cases, lack of disease-specific markers, and overlapping IHC profiles of similar diseases. We verified that the machine-learning algorithm could be applied for diagnosis precision with a generally acceptable hit rate in a nationwide dataset. Clinical and histological features should also be taken into account for the proper use of this system in the decision-making process.

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