Thoracic giant cell tumor after two total en bloc spondylectomies including one emergency surgery:A case report

BACKGROUND For patients with acute paraplegia caused by spinal giant cell tumor(GCT)who require emergency decompressive surgery,there is still a lack of relevant reports on surgical options.This study is the first to present the case of an acute paraplegic patient with a thoracic spinal GCT who underwent an emergency total en bloc spondylectomy(TES).Despite tumor recurrence,three-level TES was repeated after denosumab therapy.CASE SUMMARY A 27-year-old female patient who underwent single-level TES in an emergency presented with sudden severe back pain and acute paraplegia due to a thoracic spinal tumor.After emergency TES,the patient's spinal cord function recovered,and permanent paralysis was avoided.The postoperative histopathological examination revealed that the excised neoplasm was a rare GCT.Unfortunately,the tumor recurred 9 months after the first surgery.After 12 months of denosumab therapy,the tumor size was reduced,and tumor calcification.To prevent recurrent tumor progression and provide a possible cure,a three-level TES was performed again.The patient returned to an active lifestyle 1 month after the second surgery,and no recurrence of GCT was found at the last follow-up.CONCLUSION This patient with acute paraplegia underwent TES twice,including once in an emergency,and achieved good therapeutic results.TES in emergency surgery is feasible and safe when conditions permit;however,it may increase the risk of tumor recurrence.

Microstructure and residual stress of TiN films deposited at low temperature by arc ion plating

The TiN films were deposited on 316 L stainless steel substrates at low temperature by arc ion plating. The influences of substrate bias voltage and temperature on microstructure, residual stress and mechanical properties of the films were investigated by EDS, SEM, XRD and nanoindenter tester, respectively. The results showed that the TiN films were highly oriented in（111） orientation with a face-centered cubic structure. With the increase of substrate bias voltage and temperature, the diffraction peak intensity increased sharply with simultaneous peak narrowing, and the small grain sizes increased from 6.2 to 13.8 nm. As the substrate temperature increased from 10 to 300℃, the residual compressive stress decreased sharply from 10.2 to 7.7 GPa, which caused the hardness to decrease from 33.1 to 30.6 GPa, while the adhesion strength increased sharply from 9.6 to 21 N.

Piezoresistive MXene/Silk fibroin nanocomposite hydrogel for accelerating bone regeneration by Re-establishing electrical microenvironment

The electrical microenvironment plays an important role in bone repair.However,the underlying mechanism by which electrical stimulation(ES)promotes bone regeneration remains unclear,limiting the design of bone microenvironment-specific electroactive materials.Herein,by simple co-incubation in aqueous suspensions at physiological temperatures,biocompatible regenerated silk fibroin(RSF)is found to assemble into nanofibrils with aβ-sheet structure on MXene nanosheets,which has been reported to inhibit the restacking and oxidation of MXene.An electroactive hydrogel based on RSF and bioencapsulated MXene is thus prepared to promote efficient bone regeneration.This MXene/RSF hydrogel also acts as a piezoresistive pressure transducer,which can potentially be utilized to monitor the electrophysiological microenvironment.RNA sequencing is performed to explore the underlying mechanisms,which can activate Ca^(2+)/CALM signaling in favor of the direct osteogenesis process.ES is found to facilitate indirect osteogenesis by promoting the polarization of M2 macrophages,as well as stimulating the neogenesis and migration of endotheliocytes.Consistent improvements in bone regeneration and angiogenesis are observed with MXene/RSF hydrogels under ES in vivo.Collectively,the MXene/RSF hydrogel provides a distinctive and promising strategy for promoting direct osteogenesis,regulating immune microenvironment and neovascularization under ES,leading to re-establish electrical microenvironment for bone regeneration.