BACKGROUND: Cervical articular process joint (CAPJ) therapy is advocated for horses with neck disorders. Several ultrasound-guided CAPJ techniques have been described in cadaver studies with 72%-89% intra-articular injection accuracy; however, the CAPJ injection accuracy in clinical equine practice has not been extensively reported.
OBJECTIVE: To describe a modified cranial approach for ultrasound-guided caudal CAPJ injections, to investigate the accuracy of this CAPJ injection technique in live horses, and to assess the effect of CAPJ injection location, laterality, operator, and radiographic CAPJ enlargement on injection accuracy.
METHODS: Retrospective case study.
METHODS: Medical records of adult horses in which ultrasound-guided caudal (C4-T1) CAPJ injections were performed using a modified cranial approach between November 2006 and December 2020 were reviewed. Radiographic images of caudal cervical vertebrae were assessed by a blinded radiologist and the degree of CAPJ enlargement was graded using a previously described grading system (Rgrade 1-5b). Ultrasound-guided caudal CAPJ injection accuracy was determined by synovial fluid retrieval during an individual CAPJ injection. Statistical analysis was performed using mixed-effects multivariable logistic model to evaluate the association of CAPJ injection accuracy and the CAPJ injection location, Rgrade, laterality (right, left), and operator.
RESULTS: The study included 149 horses with 177 hospital admissions. Synovial fluid was obtained from 586/658 (89.1%) caudal CAPJs using modified cranial ultrasound-guided approach for CAPJ injections. C6-C7 CAPJ injections had 7-fold higher likelihood (OR = 6.78, 95% CI: 1.67-27.52; p = 0.007) of synovial fluid retrieval compared with C4-C5 CAPJ injections. Operator, CAPJ injection side (left, right), and degree of radiographic CAPJ enlargement did not have significant effects on the success of synovial fluid retrieval from ultrasound-guided caudal CAPJ injections.
CONCLUSIONS: Retrospective study design.
CONCLUSIONS: Intra-articular ultrasound-guided caudal CAPJ injections using a modified cranial approach can be performed accurately in live horses with and without CAPJ arthropathy.
摘要 背景: 开始提倡颈椎关节突关节(CAPJ)治疗用于马的颈部疾病。几种超声引导的CAPJ技术已经在尸体研究中宣称有72‐89%的关节内注射准确率，但是临床活马实践中的CAPJ注射准确率尚未有广泛报道。. 目的: 描述一种改进的前侧入路，用于超声引导下的尾侧CAPJ注射，研究这种CAPJ注射技术在活马体内的准确性，并评估CAPJ注射位置、侧边、操作人员和影像学CAPJ扩大对注射精度的影响。. 研究设计: 回顾性案例研究. 方法: 回顾了2006年11月至2020年12月间，采用改良前侧入路对成年马进行超声引导尾侧(C4‐T1) CAPJ注射的医疗记录。由盲态放射科医师核查评估椎骨尾侧的影像学图像，并使用先前描述的分级系统(Rgrade 1‐5b)对CAPJ扩大程度进行分级。超声引导的尾侧CAPJ注射准确性是通过单个CAPJ注射时的滑液回流来确定。采用混合效应多变量logistic模型进行统计分析，评估CAPJ注射准确率与CAPJ注射位置、Rgrade、侧边度(右、左)和操作者之间的关系。. 结果: 这项研究包括了149匹马及177个住院病例。采用改良前侧超声引导入路对尾侧CAPJ进行注射，其中586/658(89.1%)有滑液回流。C6‐C7的CAPJ注射与C4‐C5注射CAPJ相比，准确率/滑液回流可能性高7倍(OR = 6.78， 95% CI: 1.67–27.52；p = 0.007)。操作人员、CAPJ注射侧(左、右)和x线片CAPJ扩大程度对超声引导下尾侧CAPJ注射滑液成功回流无显著影响。. 主要局限性: 回顾性研究设计. 结论: 超声引导下经改良前侧入路的尾侧CAPJ关节内注射可以准确地用于有或没有CAPJ关节病的活马。.

Objective: To establish sagittal area and length reference values and ratios between apparently normal canine cervical vertebrae and intervertebral disks using magnetic resonance imaging. Sample: Retrospective evaluation of cervical vertebral column magnetic resonance imaging studies of 44 dogs representing 5 different breeds (Labrador Retriever, n = 10; French Bulldog, n = 10; Great Dane, n = 9; Chihuahua, n = 10; Dachshund, n = 5). Procedures: Mid-sagittal measurements of vertebral body and disk areas were obtained from C3 through C7 vertebrae and C2/C3 through C6/C7 intervertebral disks. Disk to vertebra area ratios were calculated and compared among dog breeds. Additionally, sagittal vertebral body and disk length measurements were obtained and disk to vertebra length ratios calculated. Inter and intra observer variability was assessed. Results: There were significant differences for disk to vertebral body area and length ratios between evaluated dog breeds and cervical vertebral locations (p < 0.001). Mean area ratio of Chihuahuas was significantly larger than all other breeds, while results from Dachshunds were only significantly different than Chihuahuas and Labrador Retrievers. Mean area ratios were statistically different between the cranial and caudal cervical vertebral locations. Regarding length ratios, results from Chihuahuas were significantly different than all breeds except Dachshunds. Mean length ratios were statistically different between all cervical locations, except C2/C3 compared to C3/C4. Intra- and interobserver variability was very good to excellent. Conclusion and Clinical Relevance: There are significant differences in area and length ratios between dog breeds. Differences also exist in area and length ratios between the cranial and caudal cervical vertebral column. These differences may play a role in the development of vertebral column diseases including intervertebral disk disease.

Diagnostic imaging is one of the pillars in the clinical workup of horses with clinical signs of cervical spinal disease. An improved awareness of morphologic variations in equine cervical vertebrae would be helpful for interpreting findings. The aim of this anatomic study was to describe CT variations in left-right symmetry and morphology of the cervical and cervicothoracic vertebrae in a sample of horses. Postmortem CT examinations of the cervical spine for horses without congenital growth disorders were prospectively and retrospectively recruited. A total of 78 horses (27 foals, 51 mature horses) were evaluated. Twenty-six horses (33.3%) had homologous changes in which a transposition of the caudal part of the transverse process (caudal ventral tubercle) of C6 toward the ventral aspect of the transverse process of C7 was present (n = 10 bilateral, n = 12 unilateral left-sided, n = 4 unilateral right-sided). There was one horse with occipito-atlantal malformation, two horses with rudimentary first ribs bilaterally, and one horse with bilateral transverse processes at Th1, representing homeotic (transitional) vertebral changes. Chi-square tests identified no significant differences in the number of conformational variations between the group of mature horses with or without clinical signs (P = 0.81) or between the group of mature horses and the group of foals (P = 0.72). Findings indicated that, in this sample of horses, the most frequently identified variations were homologous variations (transposition of the caudal part of the transverse process of C6-C7) in the caudal equine cervical vertebral column. Homeotic (transitional) variations at the cervicothoracic vertebral column were less common.

During both locomotion and body movements at stance, the head and neck of the horse are a major craniocaudal and lateral balancing mechanism employing input from the visual, vestibular and proprioceptive systems. The function of the equine neck has recently become the focus of several research groups; this is probably also feeding on an increase of interest in the equine neck in equestrian sports, with a controversial discussion of specific neck positions such as maximum head and neck flexion. The aim of this review is to offer an overview of new findings on the structures and functions of the equine neck, illustrating their interplay. The movement of the neck is based on intervertebral motion, but it is also an integral part of locomotion; this is illustrated by the different neck conformations in the breeds of horses used for various types of work. The considerable effect of the neck movement and posture onto the whole trunk and even the limbs is transmitted via bony, ligamentous and muscular structures. Also, the fact that the neck position can easily be influenced by the rider and/or by the employment of training aids makes it an important avenue for training of new movements of the neck as well as the whole horse. Additionally, the neck position also affects the cervical spinal cord as well as the roots of the spinal nerves; besides the commonly encountered long-term neurological effects of cervical vertebral disorders, short-term changes of neural and muscular function have also been identified in the maximum flexion of the cranial neck and head position. During locomotion, the neck stores elastic energy within the passive tissues such as ligaments, joint capsules and fasciae. For adequate stabilisation, additional muscle activity is necessary; this is learned and requires constant muscle training as it is essential to prevent excessive wear and tear on the vertebral joints and also repetitive or single trauma to the spinal nerves and the spinal cord. The capability for this stabilisation decreases with age in the majority of horses due to changes in muscle tissue, muscle coordination and consequently muscle strength.