A Preliminary Study On The Clinical Application Of Musculoskeletal Ultrasound For Assessing Cervical Luschka's Joint

Background: Cervical spondylosis with osteophyte formation of Luschka's joints have been recognized as one of the main etiology of mechanical compression of vertebral artery(VA),and Cervical Spondylosis of Vertebral Artery type(CSA) may occur in this process. Present diagnotic tools such as CT,MRI,DSA have the defect of being expensive,invasive,complex,and so on. Musculoskeletal ultrasound is a new imaging modality benefited from the recent exponential improvement in probe technology with high frequency and resolution,to the extent that it is an important diagnostic tool for abnormalities of the superficial musculoskeletal system.Aim:In this study,MSUS is used for exploring UJ for the first time,with the aim to find out a method for observing UJ,explain the ultrasound image of UJ and its relationship with the adjacent tissues especially with VA,assess and measure the UJ with lateral osteophyte formation so as to make foundation for quantifying the influence of UJ proliferation on the VA.Methods: This study is divided into two parts:Ⅰ. To find out a method for observing UJ by MSUS:MSUS is used for observing UJ on the human dry cervical spine and neck specimen respectively, to explore the steps of observing UJ,and make sure that whether UJ and adjacent tissues could be clearly shown in the image of MSUS.Ⅱ.Clinical application of MSUS:According to the inclusion and exclusion criteria, 23 patients clinically diagnosed as CSA are included. Each patient is checked by MSUS in the light of steps from the first part. Meanwhile, we assess whether there is spur from the lateral of the UP,and try to conceive a method to measure the UJ with lateral osteophyte formation. All the patients are given the examinations of cervical 3D-CTA, to assess and measure the UJ in the same way. With 3D-CTA as the gold standard,the assessment and measurement results of MSUS and 3D-CTA are compared and the relevance and consistency between them are analysed. The validity and reliability of MSUS assessing UJ with lateral osteophyte formation are also calculated.Results:Ⅰ. The method for exploration UJ by MSUS : the examination position is supine, with neck elevating 15cm and 45°of contralateral turning. The probe of MSUS is situated at the medial border of Sternocleidomastoid. First, we look for the transverse processes with strong echo and regard them as landmaks, then move the probe gently until the UJ and VA can be seen.Ⅱ. The image of UJ and its adjacent tissues:the UJ lies between the two transverse processes and behind the VA. When probing longitudinally,the base of UP is continued with the upper margin of the vertebrae,and the lateral border of the UP is on a straight line with the lateral margin of vertebral body,with VA in front of the line. It is the joint space that locates between the UP and its corresponding recess as a echo-free zone. When probing transversely,we can see the strong echo of the cortex of the UJ lay behind the VA.Ⅲ. MSUS assess and measure UJ with lateral osteophyte formation:some images of the UP pass the line and become more near to the VA,making the VA tortuous or stenosed. In this condition,we assess the UJ exists lateral osteophyte formation,measure the distance from cutting-line of lateral cortical matgines of the cervical vertebrae to outer cortical margines of the lateral of the UP. Statistical analysis showed that there is no significant difference between the assessment results of MSUS and 3D-CTA,and they have good correlation and consistency(r=0.65,Kappa value=0.848 ) . The sensitivity, specificity, accuracy , positive likelihood ratio, negative likelihood ratio and Youden's index are 86.44%,96.80%,93.48%,27.01,0.14 and 83.24% respectively. There is also no significant difference between the measurement results of MSUS and 3D-CTA,and they have good correlation(r=0.996,p<0.01). The consistency between two operators of MSUS who complete the examination in the same day independently and two times of one operator of MSUS in one week's interval are analysed,and the Kappa value are 0.7712 and 0.8350 respectively.Conclusions: MSUS can clearly show the UJ and its adjacent tissues especially VA, and can assess and measure the UJ of lateral osteophyte formation with satisfying validity and reliability,to the extent that it can lay foundation for quantifying the effect of osseous hypertrophy of UJ on the VA. Since MSUS can offer inexpensive, noninvasive,non-radiative and rapid examination,We strongly advocate that MSUS can be used prior to any other tools as screening method for patients clinically diagnosed as CSA. It is of great importantance to reveal the pathogenesis of CSA,and is possible to bulid a theoretical basis for the diagnosis and treatment of CSA.