Percutaneous treatments for trigeminal neuralgia (tn) including glycerol rhizotomy (GR), radiofrequency thermocoagulation (Rt), and balloon compression (Bc) are effective for patients with medical comorbidities and risk factors of microvascular decompression (MVD). these procedures are usually performed under fluoroscopy. Surgeons advance the needle to the trigeminal plexus through the foramen ovale while observing landmarks of fluoroscopic images; however, it is sometimes difficult to appropriately place the needle tip in Meckel's cave. We present the technical details of percutaneous GR using a single-plane, flat panel detector angiography system to check the needle positioning. When the needle tip may be located near the trigeminal cistern, three-dimensional (3-D) bone images are taken with cone-beam computed tomography (ct). these images clearly show the position of the needle tip in Meckel's cave. if it is difficult to place it through the foramen ovale, surgeons perform cone beam ct to observe the actual position of the needle tip at the skull base. after confirming the positional relation between the needle tip and foramen ovale, surgeons can advance it in the precise direction. in 10 procedures, we could place the nerve-block needle in about 14.5 minutes on average without complications. We think that our method is simple and convenient for percutaneous treatments for tn, and it may be helpful for surgeons to perform such treatments.

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Molecular orbital (MO) calculations of two cycloadditions, ethylene to 1-thiabutadiene and to tropothione, are made so as to compare the reactivities of [4 + 21 and 18 + 21 additions. Transitionstate (TS) geometries are examined with various computational methods, followed by a search for intrinsic reaction coordinates (IRCs). Two concerted paths are almost synchronous. On account of the large lobe of frontier MOs (FMOs) on the sulfur atom, the small activation energies of the [4 + 21 and [8 + 21 additions are obtained. Even if the orbital phase in the free reactant does not give the favorable FMO interaction, it may be converted to the proper phase on the IRC route.

Background Ewing sarcoma is a malignant bone tumor; however, its prognosis has improved since the development of modern chemotherapy. Although Ewing sarcoma outcomes have improved, issues related to late complications, secondary malignant neoplasms, and late recurrence or metastasis have emerged. Case presentation We report a case of Ewing sarcoma that recurred in the occipital bone 21 years after primary tumor treatment. A 45-year-old Japanese woman with a history of Ewing sarcoma 21 years prior, was referred to our hospital due to a severe headache. A tumor was detected in the left occipital bone, and the biopsy revealed Ewing sarcoma. Metastasis was suspected because the patient had been treated for Ewing sarcoma of the left clavicle 21 years prior. There have been several cases of local recurrence or metastasis, occurring 15–20 years after the onset of the initial disease. To our knowledge, very late metastasis of Ewing sarcoma in the skull has not been reported. Conclusion We report a rare case of very late metastasis of Ewing sarcoma in the skull with a review of the literature. Delayed metastasis secondary to Ewing sarcoma can occur in the lung, which is the most common site for metastasis, as well as other regions of the body, such as the cranium.

Background: The redundant nerve root (RNR) syndrome is a pathological condition in which the cauda equina develops into a severely flexed/tortuous spiral mass above a level of severe lumbar stenosis. Case Description: A 70-year-old male presented with bilateral neurogenic claudication attributed to a MRI-documented intradural extramedullary lesion at the L1 level with severe adjacent level/inferior L2/3 stenosis. At surgery, intradural exploration at L1 revealed an edematous cauda equina consistent with the diagnosis of the RNR syndrome. Conclusion: The RNR syndrome should be included among the differential diagnostic considerations when non-enhancing lesions are encountered above levels of marked lumbar stenosis.