The subaxial cervical facet dislocation is an important and common cause of cervical spinal cord injury, which often leads to the destruction of the three column structure of the cervical spine. At present, the treatment principle of the subaxial cervical facet dislocation is generally reduction as soon as possible, complete decompression, restoration of the intervertebral height and the normal sequence of the cervical spine and reconstruction of the stability of the cervical spine. Early reduction is particularly important for patients with spinal cord injury. Although there are many ways of reduction, the best way to achieve reduction and stability is still controversial. The authors review related literatures and summarize the reduction methods of the subaxial cervical facet dislocation, so as to provide reference for the clinical treatment of the subaxial cervical facet dislocation.

Objective:To explore the possible mechanism of Bcl-2/adenovirus E1B 19kDa-interacting protein 3-like (also known as NIX) mediating mitophagy in PC12 cells.Methods:The PC12 cells (rat adrenal pheochromocytoma cells) were cultured in a hypoxic incubator with a volume fraction of 1% O 2 to establish hypoxic injury models. The cells were divided into normoxia group and hypoxia groups at 6, 12, 24 and 48 hours after cells were exposed to hypoxic conditions. Afterwards, the expression levels of NIX, microtubule-associated protein 1 light chain 3 (LC3), translocase of outer mitochondrial membrane 20 (TOMM20), and cyclooxegenase 4 (COX4) were determined by Western blot analysis. Electron microscopy was used to observe the formation of autophagosomes after 24 hours of hypoxia. The mitochondria-NIX-LC3-autophagosome complexes were detected by confocal microscopy after the overexpression of NIX for 48 hours. The interaction between NIX and LC3 was verified by Co-immunoprecipitation (CoIP). After downregulation of NIX, the changes in mitochondria morphology were detected by confocal microscopy. The PC12 cells were divided into normoxia group, normoxia+ NIXshRNA group, hypoxia group and hypoxia+ NIXshRNA group, then the expression levels of NIX, LC3, TOMM20 and COX4 in each group were detected via Western blotting. Results:Compared to normoxia group, hypoxia group showed up-regulated expressions of NIX and LC3 [(0.44±0.03)∶(0.21±0.01), (1.04±0.03)∶(0.32±0.01)], and down-regulated expressions of TOMM20 and COX4 [(0.78±0.07)∶(1.46±0.08), (0.52±0.04)∶(0.98±0.06)] after 24 hours of hypoxia ( P<0.05). Autophagosomes containing mitochondria were detected by electron microscopy after 24 hours of hypoxia. The formation of the mitochondria-NIX-LC3-autophagosome complex were detected by confocal microscopy after the overexpression of NIX for 48 hours. CoIP demonstrated an interaction between NIX and LC3. Furthermore, inhibition of NIX preserved the integrity of the mitochondria compared with hypoxia group. Western blot analysis showed decreased expressions of NIX and LC3 in hypoxia+ NIXshRNA group [(0.90±0.04)∶ (1.30±0.19), (0.55±0.03)∶(0.75±0.03)] and increased expressions of TOMM20 and COX4 [(0.78±0.06)∶( 0.69±0.08), (0.81±0.07)∶( 0.81±0.07) in comparison to hypoxia group ( P<0.05). Conclusions:NIX can interact with LC3 to mediate mitophagy in PC12 cells. Therefore, the inhibition of NIX can preserve the integrity of the mitochondria and decrease the level of mitophagy, thus provide a protective effect.

Objective:To investigate the risk factors of tracheotomy after cervical spinal cord injury (CSCI) and the predictive role of key muscle strength in guiding bedside tracheotomy.Methods:A retrospective case-control study was used to analyze the clinical data of 294 patients with CSCI admitted to Xinqiao Hospital of Army Medical University from January 2009 to December 2013, including 243 males and 51 females, with the age range of 10-82 years [(48.9±14.7)years]. A total of 52 patients treated with tracheotomy (tracheotomy group), while 242 patients did receive tracheotomy (non-tracheotomy group). The indices were collected and compared between groups, including demographic data (gender, age, smoking history, cause of injury), injury severity data [level of injury, combined injury, cervical dislocation, American Spinal Cord Injury Association (ASIA) classification], and key muscle function strength [shrug (trapezius), shoulder abduction (deltoid) and elbow flexion (biceps)]. The risk factors affecting the tracheotomy were identified by the univariate logistic regression analysis and binary logistic regression analysis. The independent risk factor for tracheostomy and predictive role of key muscle strength was determined by the multiple logistic regression analysis.Results:Smoking history, falling injury, cervical dislocation, C 2-C 4 AISA scale A, shoulder-shrugging muscle strength, shoulder abduction muscle strength and elbow flexion strength were significantly different between groups ( P<0.05). Through the binary logistic regression analysis, it was preliminarily concluded that smoking history, traffic injury, falling injury, cervical dislocation, C 2-C 4 AISA scale A, and C 5-C 8 AISA scale A were statistically significant between groups ( P<0.05). The multiple logistic regression analysis showed smoking history( OR=2.27), cervical dislocation( OR=3.70) and C 2-C 4 AISA scale A ( OR=8.31) were significantly related to tracheostomy ( P<0.05). The multiple logistic regression analysis showed shoulder-shrugging muscle strength grade 3 and below and shoulder abduction muscle strength grade 2 and below had significant correlations with CSCI patients who required tracheotomy ( P<0.05). Conclusions:C 2-C 4 AISA scale A, cervical dislocation and smoking history are independent risk factors for determining whether the CSCI patients require tracheostomy. Shoulder-shrugging muscle strength grade 3 and below and shoulder abduction muscle strength grade 2 and below can be used to differentiate the bedside tracheotomy.

Objective:To construct a classification and regression tree which can be used to guide the tracheostomy for traumatic cervical spinal cord injury (TCSCI) based on the identification of the risk factors for TCSCI.Methods:The 498 patients with TCSCI were retrospectively analyzed who had been treated at Department of Orthopedics, The Second Hospital Affiliated to Army Medical University from January 2009 to December 2018. There were 403 males and 86 females, with an age of (50.2±13.6) years. Of the patients, 69 received tracheostomy and 420 did not. The gender, age, smoking history, injury cause, neurological level of injury (NLI), American Spinal Cord Injury Association (ASIA) grade, injury severity score (ISS), thoracic injuries, prior pulmonary diseases, prior basic diseases, and operative approaches of the patients were statistically analyzed by single factor analysis. After the independent risk factors for tracheostomy were analyzed by binary logistic regression, the classification and regression tree was developed which could be used to guide the tracheostomy.Results:The logistic regression analysis showed age>50 years ( OR=4.744, 95% CI: 1.802 to 12.493, P=0.002), NLI at C 4 and above ( OR=23.662, 95% CI: 8.449 to 66.268, P<0.001), ASIA grade A ( OR=40.007, 95% CI: 12.992 to 123.193, P<0.001), and ISS score>16 ( OR=10.502, 95% CI: 3.909 to 28.211, P<0.001) were the independent risk factors for the tracheotomy. The classification and regression tree revealed that ASIA grade A and NLI at C 4 and above were the first and second decision nodes, which had a strong predictive effect on tracheostomy. 86.84% of the patients with ASIA grade A and NLI at C 4 and above underwent tracheostomy. Conclusion:Our classification and regression tree shows that NLI at C 4 and above and ASIA grade A have a strong guiding effect on tracheotomy for TCSCI.