Abstract：
OBJECTIVE: To evaluate both the short-term and long-term outcomes of odontoid screw fixation (OSF), identifying potential risk factors for implant-related complications in patients with odontoid fractures.
METHODS: This is a retrospective observational cohort study. Inclusion criteria were as follows: 1) Type II fractures and rostral Type III fractures, according to the Anderson and D\'Alonzo classification; 2) patients older than 15 years. Exclusion criteria were: 1) other Type III injuries; 2) osteoporosis confirmed by densitometry or a CT bone density score below 100 Hounsfield units; 3) odontoid fractures related to tumors or aneurysmal bone cysts.
RESULTS: In total, 56 patients were considered for the analysis of short-term results, and 26 patients were evaluated for long-term outcomes. No significant differences were observed in the preoperative imaging data and intraoperative features of OSF between patients with Type II and rostral Type III fractures. The mean operative duration was 63.9 ± 20.9 min, and the mean intraoperative blood loss was 22.1 ± 22.9 ml. Screw cut-out was identified in four patients with rostral Type III fractures (p = 0.04). The rate of screw cut-out was found to correlate with the degree of dens fragment displacement. The bone fusion rate was 95.7%. CT scans identified stable pseudarthrosis in two cases. We observed C2-C3 ankylosis in all cases following partial disc resection. One third of patients with screws placed through the anterior lip of C2 showed no C2-C3 ankylosis. A strong trend towards lateral joint ankylosis formation in patients with a median lateral mass dislocation of 11.9 mm was observed. Most SF-36 scores either matched or exceeded the corresponding normal median values in the published reference database.
CONCLUSIONS: OSF is a reliable treatment method of Type II and rostral Type III odontoid fractures with fragment displacement of 4 mm or less. The minimally invasive OSF through the anterior-inferior lip of C2, using monocortical screw placement and cannulated instruments, without rigid intraoperative head immobilization, is sufficient to achieve favorable clinical and fusion results. This technique reduces the risk of ankylosis in the C2-C3 segment. OSF restore the quality of life for patients with odontoid fractures to levels comparable to those of the general population norm.
METHODS: This is a retrospective observational cohort study. Inclusion criteria were as follows: 1) Type II fractures and rostral Type III fractures, according to the Anderson and D\'Alonzo classification; 2) patients older than 15 years. Exclusion criteria were: 1) other Type III injuries; 2) osteoporosis confirmed by densitometry or a CT bone density score below 100 Hounsfield units; 3) odontoid fractures related to tumors or aneurysmal bone cysts.
RESULTS: In total, 56 patients were considered for the analysis of short-term results, and 26 patients were evaluated for long-term outcomes. No significant differences were observed in the preoperative imaging data and intraoperative features of OSF between patients with Type II and rostral Type III fractures. The mean operative duration was 63.9 ± 20.9 min, and the mean intraoperative blood loss was 22.1 ± 22.9 ml. Screw cut-out was identified in four patients with rostral Type III fractures (p = 0.04). The rate of screw cut-out was found to correlate with the degree of dens fragment displacement. The bone fusion rate was 95.7%. CT scans identified stable pseudarthrosis in two cases. We observed C2-C3 ankylosis in all cases following partial disc resection. One third of patients with screws placed through the anterior lip of C2 showed no C2-C3 ankylosis. A strong trend towards lateral joint ankylosis formation in patients with a median lateral mass dislocation of 11.9 mm was observed. Most SF-36 scores either matched or exceeded the corresponding normal median values in the published reference database.
CONCLUSIONS: OSF is a reliable treatment method of Type II and rostral Type III odontoid fractures with fragment displacement of 4 mm or less. The minimally invasive OSF through the anterior-inferior lip of C2, using monocortical screw placement and cannulated instruments, without rigid intraoperative head immobilization, is sufficient to achieve favorable clinical and fusion results. This technique reduces the risk of ankylosis in the C2-C3 segment. OSF restore the quality of life for patients with odontoid fractures to levels comparable to those of the general population norm.
摘要：
目的：评估齿状突螺钉固定（OSF）的短期和长期结果，确定齿状突骨折患者种植相关并发症的潜在危险因素。
方法：这是一项回顾性观察性队列研究。纳入标准如下：1）II型骨折和头端III型骨折，根据Anderson和D'Alonzo分类；2）年龄超过15岁的患者。排除标准为：1）其他III型损伤；2）通过密度测定或CT骨密度评分低于100Hounsfield单位确认的骨质疏松症；3）与肿瘤或动脉瘤性骨囊肿有关的齿状突骨折。
结果：总计，56名患者被考虑进行短期结果分析，26例患者接受了长期结局评估.II型和头端III型骨折患者的术前影像学数据和术中OSF特征没有显着差异。平均手术时间为63.9±20.9分钟，术中平均出血量为22.1±22.9ml。在四名头端III型骨折患者中发现了螺钉切口（p=0.04）。发现螺钉切口的速率与窝点碎片移位的程度相关。骨融合率为95.7%。CT扫描在2例中确定了稳定的假关节。我们观察到部分椎间盘切除术后所有病例的C2-C3强直。通过C2前唇放置螺钉的患者中有三分之一没有C2-C3强直。在中位侧块脱位为11.9mm的患者中，观察到外侧关节强直形成的强烈趋势。大多数SF-36得分匹配或超过已发布的参考数据库中的相应正常中值。
结论：OSF是治疗II型和头端III型齿状突骨折的可靠方法，碎片移位小于等于4mm。通过C2的前下唇微创OSF，使用单皮质螺钉放置和插管器械，没有刚性的术中头部固定，足以获得良好的临床和融合结果。该技术降低了C2-C3节段强直的风险。OSF可将齿状突骨折患者的生活质量恢复到与一般人群常模相当的水平。
方法：这是一项回顾性观察性队列研究。纳入标准如下：1）II型骨折和头端III型骨折，根据Anderson和D'Alonzo分类；2）年龄超过15岁的患者。排除标准为：1）其他III型损伤；2）通过密度测定或CT骨密度评分低于100Hounsfield单位确认的骨质疏松症；3）与肿瘤或动脉瘤性骨囊肿有关的齿状突骨折。
结果：总计，56名患者被考虑进行短期结果分析，26例患者接受了长期结局评估.II型和头端III型骨折患者的术前影像学数据和术中OSF特征没有显着差异。平均手术时间为63.9±20.9分钟，术中平均出血量为22.1±22.9ml。在四名头端III型骨折患者中发现了螺钉切口（p=0.04）。发现螺钉切口的速率与窝点碎片移位的程度相关。骨融合率为95.7%。CT扫描在2例中确定了稳定的假关节。我们观察到部分椎间盘切除术后所有病例的C2-C3强直。通过C2前唇放置螺钉的患者中有三分之一没有C2-C3强直。在中位侧块脱位为11.9mm的患者中，观察到外侧关节强直形成的强烈趋势。大多数SF-36得分匹配或超过已发布的参考数据库中的相应正常中值。
结论：OSF是治疗II型和头端III型齿状突骨折的可靠方法，碎片移位小于等于4mm。通过C2的前下唇微创OSF，使用单皮质螺钉放置和插管器械，没有刚性的术中头部固定，足以获得良好的临床和融合结果。该技术降低了C2-C3节段强直的风险。OSF可将齿状突骨折患者的生活质量恢复到与一般人群常模相当的水平。
