Prevalence of chronic postsurgical pain after thoracotomy and total knee arthroplasty: a retrospective multicenter study in Japan (Japanese Study Group of Subacute Postoperative Pain).

We performed a multicenter observational study to assess the prevalence and risk factors of persistent pain after lung cancer surgery and total knee arthroplasty (TKA) in the Japanese population. After receiving Ethics Committee approval, a retrospective chart review was performed for patients who underwent surgery at seven university hospitals in Japan in 2013. A total of 511 patients who underwent lung cancer surgery and 298 patients who underwent TKA were included. The prevalence of chronic postsurgical pain (CPSP) at 3 and 6 months was 18 and 12% after lung surgery and 49 and 33% after TKA, respectively. The prevalence of analgesic use at 3 and 6 months was 16 and 9% after lung surgery and 34 and 22% after TKA, respectively. In both groups, preoperative analgesic use was associated with CPSP. Anesthetic methods or techniques during both types of surgery did not significantly affect the prevalence of CPSP. This is the first study in which the prevalence of CPSP after lung surgery and TKA in Japanese population was extensively evaluated in a multicenter trial. Further prospective studies are needed to confirm the prevalence of CPSP in the Japanese population and to identify risk factors and prevention methods.

Emergence of non-trivial polar topologies hidden in singular stress field in SrTiO3: topological strain-field engineering.

Discovery of non-trivial topological structures in condensed matters holds promise in novel technological paradigms. In contrast to ferromagnetics, where a variety of topological structures such as vortex, meron, and skyrmion have been discovered, only few topological structures can exist in ferroelectrics due to the lack of non-collinear interaction like the Dzyaloshinskii-Moriya interaction in ferromagnetics. Here, we demonstrate that polarization structures with a wide range of topological numbers (winding numbernfrom -3 to +1) can be mechanically excited and designed by the mode-I singular stress field formed near the crack-tip in incipient ferroelectric SrTiO3. Our phase-field simulations based on Ginzburg-Landau theory successfully reveals that the near-tip polar topology is driven by the flexoelectric coupling with intense strain gradient at the tip, while a variety of the far-field topological structures is triggered by a collaboration between the electrostrictive and flexoelectric effects. The strain (gradient) field analysis further shows that the unexpected topological characters are implied in the singular stress field, which develops a variety of polar topologies near the crack tip. Therefore, our work provides a novel insight into the unusual interplay between mechanical- and ferroelectric-topologies, i.e. 'topological strain-field engineering', which paves the way to the mechanical design of functional topologies in the matter.

Total Spinal Epidural "Blood Patch" Application Through a Racz Catheter in Spontaneous Intracranial Hypotension.

BACKGROUND: Epidural "blood patch" (EBP) is a standard treatment of spontaneous intracranial hypotension (SIH). In recent years, there are some reports of Racz catheter use for EBP performance at upper cervical spine levels. However, the practical use of Racz catheter for single-entry multisite EBP has never been reported until now. CASE DESCRIPTION: We treated a 60-year-old man diagnosed with SIH presenting with cerebrospinal fluid leaks from the cervical to the sacral segments. We discuss the advantages of the single-entry multisite EBP and the convenience of Racz catheter use in such cases. CONCLUSIONS: The Racz catheter can be a convenient means to deliver large-volume EBPs from a single entry point in the treatment of SIH.

A case of anesthesia mumps that required postoperative re-intubation.

We encountered a 59-year-old man who first underwent left internal carotid endarterectomy for left internal carotid artery stenosis and then presented with postoperative swelling of the bilateral salivary glands. He then developed upper airway obstruction that required emergency tracheal intubation. The most likely cause was thought to be anesthesia mumps, which involves a complex interaction of multiple factors including pneumoparotitis, venous congestion, and excess saliva secretion. Many cases of salivary gland swelling recover after follow-up observation alone if there are no inflammatory findings; however, severe complications may sometimes occur. If upper airway obstruction develops as in the present case, then emergency airway management must also be considered and conscientious observation is necessary.