Anterior Full-endoscopic Single-port Double Transcorporeal Spinal Cord Decompression for Noncontinuous Two-segment Cervical Spondylotic Myelopathy: A Technical Note.

OBJECTIVE: In clinical practice, noncontinuous two-segment spinal cord cervical spondylosis is a particular form of cervical degenerative disease. Traditional anterior open surgery frequently comes with severe trauma, risks, and debatable treatment options. This study aimed to describe for the first time a novel minimally invasive technique, namely, anterior full-endoscopic single-port double transcorporeal spinal cord decompression for the treatment of patients with noncontinuous two-segment cervical spondylotic myelopathy. METHOD: From February 2020 to May 2021, five patients with noncontinuous two-segment cervical spondylotic myelopathy were treated with anterior full-endoscopic single-port double transcorporeal spinal cord decompression. Two bone channels were established by the trephine through the vertebral body oblique upward and downward to the herniated disc osteophyte complex, and the full-endoscopic system could decompress the spinal cord through the channels. All cases were followed up for over 2 years. The modified Japanese Orthopaedic Association (mJOA) score and visual analogue scale (VAS) score before and after operation and during follow-up were used to evaluate the clinical effectiveness. Radiological examinations, including CT and MRI, were utilized to evaluate the efficacy of spinal cord decompression and bone channel repair. RESULTS: All operations were successfully completed and the average operation time was 185 min, with no operation-related complications. Compared with the preoperative evaluation, the mJOA score and VAS score were improved at each time point after operation and follow-up. Postoperative CT and MRI scans showed that the intervertebral disc-osteophyte complex was removed through the vertebral bone passage, and the spinal cord was fully decompressed. After 24 months of follow-up, CT and MRI scans showed that the bone channel was almost repaired and healed. CONCLUSION: Anterior full-endoscopic single-port double transcorporeal spinal cord decompression is an effective minimally invasive technique for noncontinuous two-segment cervical spondylosis. It provides precise and satisfactory spinal cord decompression under endoscopic visualization with minimum trauma.

Effects of flotation and acid treatment on unburned carbon recovery from atmospheric circulating fluidized bed coal gasification fine ash and application evaluation of residual carbon.

The high carbon content (20-60%) in coal gasification fine ash (CGFA) makes CGFA unable to be directly used in the building materials and ceramic industries, and can only be dissipated in landfills, which brings serious environmental safety problems. This paper uses physical (flotation method) and chemical (multi-stage pickling method) methods to treat CGFA, analyze the separated carbon, and evaluate its application. The carbon content of the filter cake ash (FCA) residual carbon recovered by the flotation method is slightly increased, and the carbon ash separation effect for the water-containing CGFA is poor. The carbon content of dry ash (DA) recovered carbon in acid treatment increased from 16.33% to 89.97%. The specific surface area of the acid-washed recovered carbon is 6-34 times that of the original sample, and the specific surface area of dry ash-HCl/HF/HCl (DA-CFC) is as high as 425.31 m2/g, and its pore structure network is more developed than before deashing. After pickling treatment, the microcrystalline structure changes, the carbon skeleton becomes looser, the degree of crosslinking decreases, and the reaction activity increases. The relative content of CC in the acid-washed recovered carbon increased by 6.4-46.3%, and the relative content of functional group CH bonds increased by 48.5-89.5%. Compared with the activation energy of the original sample, the activation energy E of the sample after flotation and acid treatment is reduced, and the reaction activity is enhanced. Flotation and pickling methods can improve the grade of fuel, and multi-stage pickling methods to obtain high specific surface area carbon can be used as a precursor for the preparation of activated carbon. Carbon-ash separation of DA by flotation method can be applied to fuel combustion, fine chemical industry, and road filling. However, for FCA, it is necessary to use a pickling scheme for carbon-ash separation to realize resource utilization and harmlessness.