新枕颈距离测量方法在颅底凹陷症手术中的应用及临床意义

The application and clinical significance of a new occipitocervical distance measurement method in the operation of basilar invagination

中文关键词:  颅底凹陷症  枕颈距离  颈椎X线片  枕颈融合术  低位颅神经麻痹

英文关键词:Basilar invagination  Occipitocervical distance  Cervical spine X-ray  Occipitocervical fusion

中文摘要:

  【摘要】 目的：采用C4椎体中心至McGregor线垂直距离（the occiput-C4 distance，OC4D）测量颅底凹陷症（basilar invagination，BI）患者枕颈距离，并探讨其在枕颈融合术（occipitocervical fusion，OCF）中评估患者枕颈区纵向复位程度的可行性及临床意义。方法：回顾性分析2014年1月~2019年1月在我院就诊的82例颅底凹陷症患者的临床资料，男性23例，女性59例，平均年龄50.3±9.6岁，行OCF手术治疗56例，男性17例，女性39例，其中3例患者术后出现发音困难、吞咽困难、咽反射减弱等低位颅神经麻痹症状且无法耐受，考虑与术中患者枕颈区过度纵向撑开有关，行翻修手术以减少患者枕颈区纵向撑开距离。测量82例患者入院后术前自然站立位颈椎侧位中立位片、过伸及过屈位片上OC4D值；56例手术患者（53例OCF术后常规恢复患者和3例OCF术后翻修患者）术后住院期间复查的自然站立位颈椎侧位片上OC4D值及3例OCF术后翻修前自然站立位颈椎侧位片的OC4D值，2名脊柱外科医生不同时间单独进行2次测量。在56例手术患者入院和术后复查的颈椎CT检查中分别测量齿突尖到McRae线的垂直距离（the distance of the tip of odontoid to the McRae line，McRL）。计算53例OCF术后症状改善患者和3例OCF术后翻修患者枕颈区的纵向复位距离（患者术后OC4D值-患者术前OC4D值，d-OC4D）；记录手术患者术前及术后12个月随访时日本骨科科协会（Japanese Orthopaedic Association，JOA）评分值（17分法），计算手术患者枕颈区纵向复位率和神经功能改善率。结果：82例患者入院颈椎中立位OC4D值为49.1±7.6mm，过屈位为49.0±7.5mm，过伸位为49.0±7.7mm，三者间差异无统计学意义（P＞0.05）。颈椎中立位、过伸位及过屈位OC4D测量值在观察者间的ICC分别为0.951、0.963和0.949（P＜0.05），观察者内的ICC分别为0.977、0.982和0.971（P＜0.05）。56例手术患者中，3例行翻修手术患者术后低位颅神经麻痹症状明显缓解。56例手术患者（3例患者为翻修术后）McRL值由术前6.3±2.8mm降至术后1.8±1.2mm，颈椎中立位OC4D值由术前48.9±6.0mm增至术后53.5±6.6mm，枕颈区纵向复位距离为4.8±1.2mm，95%参考值范围为2.4～7.2mm。JOA评分由术前11.84±2.70分提高至术后12个月随访时14.88±1.74分，差异有统计学意义（P＜0.05）。手术患者枕颈区平均纵向复位率为65.8%；神经功能平均改善率为70%。d-OC4D与复位率、神经功能改善率之间相关系数r分别为0.831、0.725（P＜0.001）。结论：OC4D测量是一种简单有效的枕颈距离测量方法，在颅底凹陷症经后路枕颈融合术前可用于预估患者枕颈区纵向撑开复位的距离，术中可用于即时评估枕颈区纵向撑开复位情况，保证患者枕颈区获得充分减压复位的同时，可避免枕颈区过度纵向撑开而引起相关术后并发症。

英文摘要:

  【Abstract】 Objectives: To measure the occipitocervical distance of patients with basilar invagination(BI) through the method of measuring the vertical distance from the center of C4 vertebral body to McGregor line, and to explore the feasibility and clinical significance of such method in evaluating the longitudinal reduction of occipitocervical area during the occipitocervical fusion(OCF). Methods: The clinical data of 82 patients with BI treated at our hospital from January 2014 to January 2019 was collected, including 23 males and 59 females, aged 50.3±9.6 years. 56 patients underwent OCF surgery(17 males and 39 females), Among them, 3 patients developed low cranial nerve palsy symptoms such as dysphagia, dysphagia, reduced pharyngeal reflex and other intolerant symptoms after OCF operation, which was considered to be related to the patients' excessive longitudinal occipitocervical region distraction during operation, and revision surgery was performed to reduce the distance their longitudinal occipitocervical region distraction. The vertical distance between the center of C4 vertebral body and the McGregor′s line(OC4D) of each patient was measured on neutral radiograph of lateral cervical spine in standing position and hyperextension and hyperflexion radiograph before operation. The OC4D values on lateral radiographs of cervical spine in natural standing position of 56 patients during hospitalization after surgery were measured(53 patients with improved symptoms after OCF and 3 patients underwent revision surgery after OCF), and the OC4D values of the 3 patients who underwent revision surgery after OCF were obtained before revision on cervical lateral radiographs in natural standing position. The vertical distance of tip of the odontoid to the McRae line(McRL) was measured on CT scans of the cervical spine on admission in 56 surgical patients and during hospital admission after OCF(3 patients after revision surgery). The longitudinal reduction distance of the occipitocervical in 53 patients who routinely recovered after OCF and 3 patients who underwent revision surgery after OCF was calculated(postoperative OC4D value-preoperative OC4D value). The Japanese Orthopaedic Association(JOA) score(17 points) was recorded at preoperation and 12 months follow-up. The reduction rate of occipitocervical area and the improvement rate of neurological function were calculated. Results: The OC4D of the 82 patients with basilar invagination on admission was 49.1±7.6mm in the neutral position, 49.0±7.5mm in the hyperflexion position, and 49.0±7.7mm in the hyperextension position, showed no statistically significant difference(P>0.05). The inter-observer ICC values of OC4D measurements in neutral, hyperextension, and hyperflexion positions were 0.951, 0.963, and 0.949(P＜0.05), and the intra-observer ICC values were 0.977, 0.982, and 0.971(P＜0.05), respectively. Among the 56 patients underwent surgery, 3 patients underwent revision surgery, and the symptoms of low cranial nerve palsy were significantly relieved after revision. The lower cranial nerve palsy symptoms of the patients were significantly relieved, and there were statistically significant differences in OC4D values before and after revision surgery(P＜0.05). The MCRL value decreased from 6.3±2.8mm preoperatively to 1.8±1.2mm postoperatively. The neutral OC4D values of 56 patients increased from 48.9±6.0mm before operation to 53.5±6.6mm after operation. The occipitocervical longitudinal reduction distance was 4.8±1.2mm, and the 95% reference value range was 2.4-7.2mm. JOA score was increased from 11.84±2.70 points before surgery to 14.88±1.74 points after surgery at 12 months follow-up, with statistically significant differences(P<0.05). The average reduction rate of occipitocervical region was 65.8%. The average neurological improvement rate was 70%. The correlation coefficient between longitudinal distraction distance and reduction rate and neurological improvement rate was 0.831 and 0.725(P<0.001), respectively. Conclusions: OC4D measurement is a simple and effective occipitocervical distance measurement method, it can be used to estimate the longitudinal distraction distance in the occipitocervical region of patients, before posterior occipitocervical fusion for BI. It can be used to evaluate the longitudinal distraction of the occipitocervical region, intraoperatively, while ensuring adequate decompression reduction of the occipitocervical area, it can avoid related postoperative complications caused by excessive longitudinal occipitocervical extension.