IntroductionPosterior percutaneous endoscopic cervical foraminotomy and discectomy (P-PECD) is a minimally invasive technique for the treatment of degenerative cervical radiculopathy. The O-arm, an intraoperative mobile computed tomography (CT) scanner, may improve spine surgery outcomes.AimTo evaluate clinical outcomes of O-arm assisted P-PECD in patients with degenerative cervical radiculopathy.Material and methodsBetween January 2013 and January 2018, 32 patients with degenerative cervical radiculopathy who underwent P-PECD were followed up for 12 months. Their demographic, clinical and surgical data were reviewed retrospectively. All patients received intraoperative O-arm scanning to assess working cannula placement and decompression. The visual analogue scale (VAS), the neck disability index (NDI), and Odom’s criteria were used to evaluate clinical outcomes.ResultsCompared with preoperative values, mean NDI, neck-VAS, and arm-VAS scores were dramatically improved 1 week postoperatively, and the improvement was maintained for at least a year after surgery (from 27.6 ±10.5, 5.8 ±1.7, and 7.2 ±2.3 to 1.4 ±0.8, 1.1 ±0.8 and 0.9 ±0.6, respectively). According to Odom’s criteria, 27/32 patients (84.4%) reported excellent or good results. There were no permanent complications. One patient suffered from transient thumb weakness due to a cervical nerve root injury caused by the spinal needle.ConclusionsP-PECD aided by intraoperative O-arm imaging is a safe, effective, and minimally invasive procedure for treating degenerative cervical radiculopathy that can provide accurate cannula placement and thorough decompression.
To acquire extremely thermostable proteins of given functions is challenging for conventional protein engineering. Here we applied ABACUS, a statistical energy function we developed for de novo amino acid sequence design, to globally redesign a Ras‐binding domain (RBD), and obtained an extremely thermostable RBD that unfolds reversibly at above 110°C, the redesigned RBD experimentally confirmed to have expected structure and Ras‐binding interface. Directed evolution of the redesigned RBD improved its Ras‐binding affinity to the native protein level without excessive loss of thermostability. The designed amino acid substitutions were mostly at the protein surface. For many substitutions, strong epistasis or significantly differentiated effects on thermostability in the native sequence context relative to the redesigned sequence context were observed, suggesting the globally redesigned sequence to be unreachable through combining beneficial mutations of the native sequence. Further analyses revealed that by replacing 38 of a total of 48 non‐interfacial surface residues at once, ABACUS redesign was able to globally “invert” the protein's charge distribution pattern in an optimized way. Our study demonstrates that computational protein design provides powerful new tools to solve challenging protein engineering problems.
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