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Low back pain following spine surgery is a major complication due to excessive epidural fibrosis, which compresses the lumbar nerve. The mechanisms of epidural fibrosis remain largely elusive. In the drainage samples from patients after spine operation, neutrophil extracellular traps (NETs) and NETs inducer high-mobility group box 1 were significantly increased. In a mouse model of laminectomy, NETs developed in the wound area post epidural operation, accompanied with macrophage infiltration. In vitro, macrophages ingested NETs and thereby increased the elastase from NETs via the receptor for advanced glycation end product. Moreover, NETs boosted the expression of fibronectin in macrophages, which was dependent on elastase and could be partially blocked by DNase. NF-κB p65 and Smad pathways contributed to the increased expression fibronectin in NETs-treated macrophages. In the mouse spine operation model, post-epidural fibrosis was significantly mitigated with the administration of DNase I, which degraded DNA and cleaved NETs. Our study shed light on the roles and mechanisms of NETs in the scar formation post spine operation.

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Study Design. Anatomic study in nine fresh-frozen cadavers. Objective. To confirm the anatomical feasibility of transferring the extradural ventral roots (VRs) and dorsal roots (DRs) of contralateral C7 nerves to those of the ipsilateral C7 nerves respectively through a cervical posterior approach. Summary of Background Data. The contralateral C7 nerve root transfer technique makes breakthrough for treating spastic limb paralysis. However, its limitations include large surgical trauma and limited indications. Methods. Nine fresh-frozen cadavers (four females and five males) were placed prone, and the feasibility of exposing the bilateral extradural C7 nerve roots, separation of the extradural C7 VR and DR, and transfer of the VR and DR of the contralateral C7 to those of the ipsilateral C7 on the dural mater were assessed. The pertinent distances and the myelography results of each specimen were analyzed. The acetylcholinesterase (AChE) and antineurofilament 200 (NF200) double immunofluorescent staining were preformed to determine the nerve fiber properties. Results. A cervical posterior midline approach was made and the laminectomy was performed to expose the bilateral extradural C7 nerve roots. After the extradural C7 VR and DR are separated, the VR and DR of the contralateral C7 have sufficient lengths to be transferred to those of the ipsilateral C7 on the dural mater. The myelography results showed that the spinal cord is not compressed after the nerve anastomosis. The AChE and NF200 double immunofluorescent staining showed the distal ends of the contralateral C7 VRs were mostly motor nerve fibers, and the distal ends of the contralateral C7 DRs were mostly sensory nerve fibers. Conclusion. Extradural contralateral C7 nerve root transfer in a cervical posterior approach for treating spastic limb paralysis is anatomically feasible. Level of Evidence: 5.

Excessive post‐epidural fibrosis is a common cause of recurrent back pain after spinal surgery. Though various treatment methods have been conducted, the safe and effective drug for alleviating post‐epidural fibrosis remains largely unknown. Metformin, a medicine used in the treatment of type 2 diabetes, has been noted to relieve fibrosis in various organs. In the present study, we aimed to explore the roles and mechanisms of metformin in scar formation in a mouse model of laminectomy. Post‐epidural fibrosis developed in a mouse model of laminectomy by spinous process and the T12‐L2 vertebral plate with a rongeur. With the administration of metformin, post‐epidural fibrosis was reduced, accompanied with decreased collagen and fibronectin in the scar tissues. Mechanistically, metformin decreased fibronectin and collagen deposition in fibroblast cells, and this effect was dependent on the HMGB1/TLR4 and TGF‐β1/Smad3 signalling pathways. In addition, metformin influenced the metabolomics of the fibroblast cells. Taken together, our study suggests that metformin may be a potential option to mitigate epidural fibrosis after laminectomy.

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Transarticular screw fixation (TASF) is technically demanding, with high risk of vertebral artery (VA) injury. How to manage intraoperative VA injury and choose optimal alternative fixation becomes a concern of spinal surgeons. In this study, the management strategy for a patient with suspected intraoperative VA injury was analyzed. A 53-year-old woman developed type II odontoid fracture and brain stem injury due to a motor vehicle accident 3 months earlier. After conservative treatments, the brain stem injury improved, but with residual ocular motility defect in the right eye. The odontoid fracture did not achieve fusion with displacement and absorption of fracture fragments. After admission, atlantoaxial fixation using bilateral C1-2 transarticular screws (TASs) combined with C1 laminar hooks was planed. The first TAS was inserted successfully. Unfortunately, suspected VA injury developed during tapping the tract for the second TAS. Considering the previous brain stem injury and that directly inserting the screw to tamponade the hemorrhage might cause VA stenosis or occlusion, we blocked the screw trajectory with bone wax. C2 laminar screw was implanted instead of intended TAS on the injured side. The management strategy for suspected VA injury should depend on intraoperative circumstances and be tailored to patients. Blocking screw trajectory with bone wax is a useful method to stop bleeding. Atlantoaxial fixation using C2 laminar screw and C1-2 TAS combined with C1 laminar hooks is an ideal alternative procedure.

The aim of the present study was to investigate a novel technology, requiring only a single portal and no special equipment, to perform endoscopic treatment of carpal tunnel (CT) syndrome (CTS). This novel technique involves a surgical approach and standard operating procedures and is designed to minimize the potential for complications. Patients with CTS were randomly assigned using a computer-generated random allocation and stratified by site to either the modified endoscopic CT release (MECTR) group ( n=48) or open CT release (OCTR) group (n=46). Various medical indexes were compared between the two groups, including operative time, hospitalization time, the time required to resume a normal life or work, intraoperative complications, incision infection rate, the amelioration of symptoms (Kelly grading), post-operative scar pain score, recovery of grip strength and pinch strength, two-point discrimination and the presence of sympathetic dystrophy. The results revealed that all patients had grade A wound healing and the symptoms were completely relieved. No significant differences were observed between the two groups with regards to the incision infection rate, intra operative complications, grip strength, pinch strength, two-point discrimination, presence of sympathetic dystrophy and clinical symptom amelioration. In addition, compared with the OCTR group, the MECTR group had a decreased operative and hospitalization time, post-operative scar pain score and time required to resume a normal lifestyle. Post-operative electromyographic examination also revealed that the median nerve sensory conduction speed increased compared with that prior to surgery in both groups. In conclusion, the use of MECTR for the treatment of CTS achieved higher patient satisfaction, a shorter operative time and hospitalization time, an earlier return to work time or resumption of a normal life, as well as less post-operative scar pain compared with OCTR. Thus, these results suggested that MECTR may be an effective method for the treatment of idiopathic CTS. Trial registration no. ChiCTR2000041165, retrospectively registered 20th December 2020.