Ultrasonography of the equine cervical region: a descriptive study in eight horses

Arthroscopic removal of osteochondral fragments of the cervical articular process joints in three horses

OBJECTIVE

To report arthroscopic osteochondral fragment removal from the equine cervical spine articular process joints (APJs) including long-term follow-up.

STUDY DESIGN

Case series.

ANIMALS

Three Warmblood horses with forelimb lameness and/or reduced range of motion of the cervical spine with osteochondral fragments between the cervical vertebrae C5 /C6 or C6 /C7 .

METHOD

Arthroscopy of the APJs of C5 /C6 and C6 /C7 was performed under general anesthesia. Following endoscopic evaluation of the joints, osteochondral fragments were removed using a rongeur.

RESULTS

All horses recovered from anesthesia with no anesthetic or minor postanesthetic complications. One horse needed a second procedure for fragment removal. Fourteen to 31 months post-surgery the horses were sound for their intended use and neurological examination revealed no abnormalities.

CONCLUSION

Arthroscopic removal of osteochondral fragments can be performed safely in the equine cervical APJs of C5 /C6 and C6 /C7 resulting in a favorable long-term outcome.

CLINICAL SIGNIFICANCE

Arthroscopic removal is a valid option for horses showing clinical signs that can be attributed to osteochondral fragments in the APJs of the neck.

Dangerous Behavior and Intractable Axial Skeletal Pain in Performance Horses: A Possible Role for Ganglioneuritis (14 Cases; 2014-2019)

Introduction: Dangerous behavior is considered an undesired trait, often attributed to poor training or bad-tempered horses. Unfortunately, horses with progressive signs of dangerous behavior are often euthanized due to concerns for rider safety and limitations in performance. However, this dangerous behavior may actually originate from chronic axial skeleton pain. This case series describes the medical histories and clinical presentations of horses presented for performance limitations and dangerous behavior judged to be related to intractable axial skeleton pain.

Material and Methods: Fourteen horses that developed severe performance limitations resulting in euthanasia were included. A complete spinal examination and behavioral responses, gait and neurologic evaluations, diagnostic imaging, gross pathologic and histopathologic examinations of the axial skeleton were performed on all horses. A tentative diagnosis of the affected spinal region was formulated using medical records, owner and trainer complaints, and antemortem examination findings. The selected spinal regions were further examined with gross and histopathologic evaluations of the associated osseous, soft tissue and neural tissues.

Results: Ten horses showed severe behavioral responses during the myofascial and mobilization examinations. Based on an aggregate evaluation, the cervicothoracic and lumbosacral regions were the most common regions believed to be the primary area of concern. All horses had moderate to severe ganglionitis present at multiple vertebral levels. Subdural and epidural hemorrhage or hematomas were a common finding (71%) in the cervicothoracic and lumbosacral regions.

Discussion: In this case series, neuropathic (i.e., structural) pain was judged to be the underlying cause of dangerous behavior. The dorsal root ganglia (DRG) serve an important role in relaying peripheral sensory information to the central nervous system and ganglionitis has been associated with neuropathic pain syndromes. This series highlights the need for more in-depth understanding of pain behavior and its clinical presentation and progression in chronic or severely affected horses. Limitations of the study are the lack of age-matched control DRG and the incomplete collection of DRG from every vertebral level of interest.

Surgical removal of intra-articular loose bodies from the cervical articular process joints in 5 horses

OBJECTIVE

To describe the surgical removal of intra-articular loose bodies (LBs) from the cervical articular process joints (APJs) in five horses and to describe the outcome of the surgery.

STUDY DESIGN

Short case series.

ANIMALS

Five client-owned horses with naturally occurring LBs within the cervical APJs.

METHODS

Medical records were reviewed of horses that were diagnosed with LBs of the cervical APJs on computed tomography (CT), where the LBs were subsequently removed surgically. Details of case selection and surgical technique were reviewed along with postoperative complications and clinical outcome. Histopathology was performed on LBs in some cases.

RESULTS

Surgery was performed on six APJs in five horses. Of the 14 LBs identified with CT, 13 were successfully removed from the C4/C5, C5/C6 and C6/C7 articulations. No surgical complications were encountered, and clinical signs of cervical dysfunction improved in all horses. All clinical cases returned to ridden work by 6 months post surgery. Histopathologic examination revealed the removed structures to be osteochondral or chondral loose bodies consisting of cartilaginous proliferation with or without ossification and central necrosis.

CONCLUSIONS

Surgical removal of LBs is achievable from the cervical APJs and can result in the resolution of cervical pain. This procedure offers a new treatment option for management of selected horses with cervical pain, following thorough assessment and CT imaging.

Diagnostic Accuracy and Prognostic Significance of Point-Of-Care Ultrasound (POCUS) for Traumatic Cervical Spine in Emergency care setting: A Comparison of clinical outcomes between POCUS and Computed Tomography on a Cohort of 284 Cases and Review of Literature

Background:

The cervical spine is injured in approximately 3% of major trauma patients, and 10% of patients with serious head injury. Therefore, clearance of the cervical spine in multitrauma patients is a critically important task. This is particularly important, considering that there is a positive correlation between a Glasgow Coma Scale of <14 and cervical spine injury. Radiography is not sensitive enough to rule out cervical spine injury, especially as radiography done in the trauma setting is usually technically unsatisfactory.

Objective:

The current study aims to assess the diagnostic accuracy and prognostic significance of using bedside point-of-care ultrasound (POCUS) in traumatic cervical spine injuries compared to computed tomography (CT) as the reference standard.

Materials and Methods:

This comparative study enrolled 284 patients with severe multiple trauma at a tertiary care center between July 2017 and March 2020. The inclusion criteria included an indication of cervical spine CT scan, satisfaction of patients with participation in the study, and the lack of history of injury and severe traumatic events. The exclusion criteria were the history of a previous cervical spinal trauma, spondylosis, scoliosis, spinal tuberculosis, degenerative vertebral changes, and patients who refused to give consent to participate in research or CT scanning. The data were analyzed by SPSS software, and sensitivity, specificity, and positive predictive value (PPV)/negative predictive value (NPV) were determined based on CT findings.

Results:

The best window for the cervical spine was through the anterior triangle using the linear array probe (6–13 MHz). POCUS had a sensitivity of 78.5%, specificity of 98.4%, PPV of 93.2%, NPV of 92.8%, and accuracy of 93.2% in detecting all types of spinal injuries in comparison with CT scan as the standard modality. POCUS had a sensitivity of 100%, specificity of 92.3%, PPV of 62.3%, NPV of 100%, and accuracy of 91.7% in cases with the movement of injured particles. POCUS had a sensitivity of 32.2%, specificity of 100%, PPV of 100%, NPV of 91.4%, and accuracy of 90.8% in detecting the fracture of transverse process. POCUS had a sensitivity of 36.1%, specificity of 100%, PPV of 100%, NPV of 98.1%, and accuracy of 98.4% in ≤14-year age multitrauma patients. In comparison, the current study achieved a sensitivity of 79.4%, specificity of 95.7%, PPV of 92.1%, NPV of 86.3%, and accuracy of 88.6% in >14-year age multitrauma patients.

Conclusion:

POCUS for cervical spine is feasible using portable ultrasound machine and by neurosurgeons/radiologists/emergency physicians with basic training. It holds great potential in resource-starved settings and in unstable patients for ruling out unstable cervical spine injuries and injuries associated with the movement of fractured or dislocated particles. POCUS examination of the cervical spine was possible in the emergency setting and even in unstable patients and could be done without moving the neck. Future studies, ideally conducted as randomized control trials, are required to establish training and education standards, and to assess the feasibility and safety of POCUS as an alternative to radiography.

Anatomy of the vertebral column, ribs and sternum in orange rumped agouti (Dasyprocta leporina Linnaeus, 1758): Structural and Functional perspectives

The axial skeleton of orange rumped agouti, Dasyprocta leporina, was studied for better understanding of its locomotor behaviour. The bones from eight adult agoutis of both sexes were observed for their anatomical features and functional significance. The vertebral formula was found to be C₇ T₁₂ L₇ S₅ Cy_5-6 . The well-developed occipital crest, caudally oriented prominent axis spine and well-developed transverse processes from C₃ -C₇ indicated a highly flexible neck with greater sagittal mobility. Articular facets were horizontal in anterior series while oblique in the posterior series, which enabled them to perform both lateral and sagittal movements during locomotion. The caudally directed thoracic spines, T₁₂ as anticlinal vertebra and prominent mamillary process in the posterior series were suggestive of strong dorso-ventral flexion/extension and rotation. The robust lumbar vertebrae, well-developed transverse processes with cranio-ventral extension, were the feature for powerful sagittal/dorsoventral movement. The presence of spinous processes and well-developed transverse processes in all caudal vertebrae was an indication of a highly movable tail. The ribs were 13 pairs with first seven as sternal and six as asternal. They were laterally compressed in the anterior series as a cursorial adaptation. A strong muscular attachment to vertebrae provides this rodent speed, agility, dexterity and strength suitable for survival in food chain.

A study of ultrasound-guided perineural injection of the caudal cervical spinal nerve roots in equine cadavers

OBJECTIVES

To develop an ultrasound-guided cervical perineural injection technique for horses and to evaluate and compare the distribution of contrast agent among perineural, intra-articular and periarticular injections.

STUDY DESIGN

Prospective, experimental cadaveric study.

ANIMALS

A total of 14 equine cadaveric necks.

METHODS

Bilateral ultrasound-guided perineural injection technique for the caudal cervical spinal nerve roots (CSNRs 5-7) was developed. Paramagnetic or iodinated contrast was injected and the distribution of contrast was evaluated using magnetic resonance (MR) or computed tomography (CT) imaging, respectively. The presence of contrast in the CSNR region was determined by an observer unaware of the technique used for each injection performed. The ability of the perineural injection technique to distribute contrast agent to the CSNR region was compared with intra-articular and periarticular injection techniques.

RESULTS

Perineural injection delivered contrast agent to the CSNR region 100% of the time and was significantly different when compared with intra-articular injection (p = 0.008). There was no difference in ability to deliver contrast agent to the CSNR region between the perineural and periarticular injection techniques or between the intra-articular and periarticular injection techniques.

CONCLUSION AND CLINICAL RELEVANCE

The ultrasound-guided perineural injection technique developed in this study accurately delivered contrast agent to the CSNR region in equine cadavers. This technique could potentially be used for the diagnosis and treatment of cervical pain in horses, particularly in cases where intra-articular cervical articular process joint injections have not been beneficial. Further studies are necessary to assess the effectiveness of the ultrasound-guided perineural injection technique in live horses.

Equine Cervical Pain and Dysfunction: Pathology, Diagnosis and Treatment

Simple Summary

Neck pain and dysfunction in the horse is becoming an increasingly important topic among riders, trainers and veterinarians. Some horses may present for a subtle performance decline, while others may show dramatic, dangerous behavior. It is important to recognize how to carefully evaluate the horse in an effort to understand the different types of pain that may be contributing to the different behaviors. The musculoskeletal and nervous systems may both play a role in the development of clinical signs. Recognizing that there are many diagnostic options as well as several treatments choices is important. This synopsis covers the disease processes that may contribute to the development of neck pain and dysfunction in the horse, as well as several possible diagnostic and treatment options.

Abstract

Interest in the cervical spine as a cause of pain or dysfunction is increasingly becoming the focus of many equine practitioners. Many affected horses are presented for poor performance, while others will present with dramatic, sometimes dangerous behavior. Understanding and distinguishing the different types of neck pain is a starting point to comprehending how the clinical presentations can vary so greatly. There are many steps needed to systematically evaluate the various tissues of the cervical spine to determine which components are contributing to cervical pain and dysfunction. Osseous structures, soft tissues and the central and the peripheral nervous system may all play a role in these various clinical presentations. After completing the clinical evaluation, several imaging modalities may be implemented to help determine the underlying pathologic processes. There are multiple treatment options available and each must be carefully chosen for an individual horse. Provided is a synopsis of the current knowledge as to different disease processes that can result in cervical pain and dysfunction, diagnostic approaches and treatment strategies. Improving the knowledge in these areas will ideally help to return horses to a state of well-being that can be maintained over time and through the rigors of their job or athletic endeavors.

Chronic Atlantoaxial Luxation Imaging Features in a Pony with Intermittent Neck Stiffness

A 17-year-old mixed breed pony was presented with intermittent neck stiffness during regular training rides in the six months preceding its admission. All parameters were within the normal range, except for an increase in heart rate (48 bpm) during the examination. Concave areas were observed at the level between the atlas and axis vertebrae (C1-C2) on both the left and right sides of the neck. Radiographs were taken of the laterolateral, left ventrodorsal oblique, and right ventrodorsal oblique projections in the cranial cervical region. The images revealed severe structural disorders, including trauma with luxation of the atlantoaxial joint, a fusion of the atlas and axis vertebrae, and evidence of a false joint in the axis bone. Subsequent ultrasonography showed hyperechoic areas in the rectus capitis caudalis and obliquus capitis caudalis muscles. Neck mobility was improved after two weeks of stall rest, administration of oral phenylbutazone (4.4 mg/kg), and topical cold gel treatment. The overstretching of surrounding soft tissues accompanying chronic injury of cranial cervical area may result in neck stiffness in the aging pony. Radiographic and ultrasonographic findings were consistent with the presence of cranial cervical trauma leading to neck stiffness. These findings emphasized the essential role of imaging diagnostics in treating a pony with intermittent neck stiffness.

Evaluation of the caudal cervical articular process joints by using a needle arthroscope in standing horses

OBJECTIVE

To determine the safety and efficacy of caudal cervical articular process joint arthroscopy by using needle arthroscopy in standing sedated horses.

STUDY DESIGN

Prospective experimental case series.

ANIMALS

Six adult horses.

METHODS

Three horses underwent exploration of bilateral C5-6 vertebral articular process joints and three bilateral C6-7 articular process joints by using a 1.2 × 65-mm needle arthroscope under standing sedation. The 16-gauge arthroscopic trocar and canula assembly was inserted in the desired articular process joint under ultrasonographic guidance without distention of the joint.

RESULTS

All 12 articular process joints were successfully explored. Entering the joint on the first attempt was achieved in 10 of 12 joints. A craniodorsal approach for arthroscope insertion allowed evaluation of the most cranial aspect of the articular cartilage surface. Triangulation with a spinal needle was determined to be difficult and resulted in a limited space for movement.

CONCLUSION

Needle arthroscopy of the caudal cervical facet joints was performed safely and efficiently in standing sedated horses.

CLINICAL SIGNIFICANCE

Standing cervical articular process needle arthroscopy is a minimal morbidity technique with the potential to be an advantageous technique for the diagnosis and treatment of cervical articular process pathology.

State-of-the-Art Diagnostic Methods to Diagnose Equine Spinal Disorders, With Special Reference to Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation

Spinal cord disorders are a common problem in equine medicine. However, finding the site of the lesion is challenging for veterinarians because of a lack of sensitive diagnostic methods that can assess neuronal functional integrity in horses. Although medical imaging is frequently applied to help diagnose corticospinal disorders, this approach does not reveal functional information. For the latter, transcranial magnetic stimulation (TMS) and more recently transcranial electrical stimulation (TES) can be useful. These are brain stimulation techniques that create either magnetic or electrical fields passing through the motor cortex, inducing muscular responses, which can be recorded either intramuscularly or extramuscularly by needle or surface electrodes. This permits the evaluation of the functional integrity of the spinal motor tracts and the nerve conduction pathways. The interest in TES in human medicine emerged these last years because unlike TMS, TES tends to bypass the motor cortex of the brain and predominantly relies on direct activation of corticospinal and extrapyramidal axons. Results from human medicine have indicated that TMS and TES recordings are mildly if not at all affected by sedation. Therefore, this technique can be reliably used in human patients under either sedation or full anesthesia to assess functional integrity of the corticospinal and adjunct motor tracts. This opens important new avenues in equine medicine.

Evaluation of the applicability of musculoskeletal ultrasonography of the thoracolumbar and lumbar spine segment of healthy dogs

ABSTRACT: Changes in the spine of dogs are usually detected in clinical and in surgical practice. Few studies exist on musculoskeletal ultrasound anatomy of the thoracolumbar and lumbar segments of the normal spine of dogs. This study aimed to compare the normal musculoskeletal ultrasound anatomy of the T10-S1 vertebral segments with images obtained with magnetic resonance imaging (MRI), computed tomography (CT), and anatomical structures, and to establish the ability to identify structures using these modalities. Ultrasound scans allowed visualization of the muscles of the region, articular processes, spinous process, interspinous ligament, and yellow ligament in the lumbosacral window. Computed tomography images provided better bone details, compared to ultrasound images. Low-field MRI allowed the identification of the same structures identified with ultrasound imaging, and allowed the identification of cerebrospinal fluid, transverse processes, and provided improved detail of the intervertebral discs and spinal cord. Knowledge of ultrasound anatomy of the region may allow the the identification of muscle and ligament injuries. Thus, in cities where CT and MRI are inaccessible, ultrasonography of the region could be a good alternative to identify possible changes not observable with radiographic examination or to complement radiographic examination.

Magnetic motor evoked potentials of cervical muscles in horses

BACKGROUND

When surgical treatment of cervical vertebral malformation is considered, precise localization of compression sites is essential, but remains challenging. Magnetic motor evoked potentials (mMEP) from paravertebral muscles are useful in localizing spinal cord lesions, but no information about cervical muscle mMEP in horses is available yet. Therefore, the aim of this study was to determine the possibility, normal values, inter- and intra-observer agreement and factors that have an effect on cervical mMEP in healthy horses.

METHODS

Transcranial magnetic stimulation was performed on 50 normal horses and 4 (2 left, 2 right) muscle responses were recorded at the middle of each cervical vertebra (C1-C7) and additionally just caudal to C7 to evaluate cervical nerves (Cn) Cn1 to Cn8. Latency time and amplitude of the recorded mMEP were defined by both an experienced and an unexperienced operator.

RESULTS

Latency increased gradually from 14.2 ± 1.38 ms for Cn3 to 17.7 ± 1.36 ms for Cn8, was significantly influenced by cervical nerve (P < 0.01), gender (P = 0.02) and height (P = 0.03) and had a good intra-observer agreement. The smallest mean amplitude (4.35 ± 2.37 mV) was found at Cn2, the largest (5.99 ± 2.53 mV) at Cn3. Amplitude was only significantly influenced by cervical nerve (P < 0.01) and had a low intra-observer agreement. No significant effect of observer on latency (P = 0.88) or amplitude (P = 0.99) measurements was found.

CONCLUSION

mMEP of cervical muscles in normal horses are easy to collect and to evaluate with limited intra- and inter-observer variation concerning amplitude and should be investigated in future studies in ataxic horses to evaluate its clinical value.

Ultrasound-guided approach to the cervical articular process joints in horses: a validation of the technique in cadavers

Objectives: To compare accuracy of the ultrasound-guided craniodorsal (CrD) approach with the dorsal (D) approach to the cervical articular process joints, and to evaluate the effect of the transducer, needle gauge, and operator experience.

Methods: Cervical articular process joints from 14 cadaveric neck specimens were injected using either a D or CrD approach, a linear (13 MHx) or microconvex transducer (10 MHz), and an 18 or 20 gauge needle, by an experienced or inexperienced operator. Injectate consisted of an iodinated contrast material solution. Time taken for injection, number of redirects, and retrieval of synovial fluid were recorded. Accuracy was assessed using a scoring system for contrast seen on computed tomography (CT).

Results: The successful performance of intraarticular injections of contrast detected by CT using the D (61/68) and CrD (57/64) approaches was comparable. No significant effect of approach, transducer or needle gauge was observed on injection accuracy, time taken to perform injection, or number of redirects. The 18 gauge needle had a positive correlation with retrieval of synovial fluid. A positive learning curve was observed for the inexperienced operator.

Clinical relevance: Both approaches to the cervical articular process joints were highly accurate. Ultrasound-guided injection of the cervical articular process joints is an easilylearnt technique for an inexperienced veterinarian. Either approach may be employed in the field with a high level of accuracy, using widely available equipment.

Assessment of ultrasound as a diagnostic modality for detecting potentially unstable cervical spine fractures in pediatric severe traumatic brain injury: A feasibility study

Background:

Early cervical spine clearance is extremely important in unconscious trauma patients and may be difficult to achieve in emergency setting.

Objectives:

The aim of this study was to assess the feasibility of standard portable ultrasound in detecting potentially unstable cervical spine injuries in severe traumatic brain injured (TBI) patients during initial resuscitation.

Materials and Methods:

This retro-prospective pilot study carried out over 1-month period (June–July 2013) after approval from the institutional ethics committee. Initially, the technique of cervical ultrasound was standardized by the authors and tested on ten admitted patients of cervical spine injury. To assess feasibility in the emergency setting, three hemodynamically stable pediatric patients (≦18 years) with isolated severe head injury (Glasgow coma scale ≤8) coming to emergency department underwent an ultrasound examination.

Results:

The best window for the cervical spine was through the anterior triangle using the linear array probe (6–13 MHz). In the ten patients with documented cervical spine injury, bilateral facet dislocation at C5–C6 was seen in 4 patients and at C6–C7 was seen in 3 patients. C5 burst fracture was present in one and cervical vertebra (C2) anterolisthesis was seen in one patient. Cervical ultrasound could easily detect fracture lines, canal compromise and ligamental injury in all cases. Ultrasound examination of the cervical spine was possible in the emergency setting, even in unstable patients and could be done without moving the neck.

Conclusions:

Cervical ultrasound may be a useful tool for detecting potentially unstable cervical spine injury in TBI patients, especially those who are hemodynamically unstable.

The role of B-mode ultrasonography in the musculoskeletal anatomical evaluation of the cervical region of the dog spine

This study characterized the normal musculoskeletal anatomy of the cervical segment of the spine of dogs by means of B-mode ultrasonography. The objective was to establish the role of B-mode ultrasonography for the anatomical evaluation of the cervical spine segment in dogs, by comparing the ultrasonographic findings with images by computed tomography and magnetic resonance imaging. The ultrasound examination, in transverse and median sagittal sections, allowed to identify a part of the epaxial cervical musculature, the bone surface of the cervical vertebrae and parts of the spinal cord through restricted areas with natural acoustic windows, such as between the atlanto-occipital joint, axis and atlas, and axis and the third cervical vertebra. The images, on transverse and sagittal planes, by low-field magnetic resonance imaging, were superior for the anatomical identification of the structures, due to higher contrast between the different tissues in this modality. Computed tomography showed superiority for bone detailing when compared with ultrasonography. As for magnetic resonance imaging, in addition to the muscles and cervical vertebrae, it is possible to identify the cerebrospinal fluid and differentiate between the nucleus pulposus and annulus fibrosus of the intervertebral discs. Although not the scope of this study, with knowledge of the ultrasonographic anatomy of this region, it is believed that some lesions can be identified, yet in a limited manner, when compared with the information obtained mainly with magnetic resonance imaging. The ultrasound examination presented lower morphology diagnostic value compared with the other modalities.

Aspectos tomográficos da coluna cervical de equinos

Descreveu-se a anatomia da região cervical de equinos adultos, com base em imagens obtidas no exame de tomografia computadorizada helicoidal realizado em peças anatômicas de equinos adultos. A tomografia computadorizada foi o método de imagem diagnóstica de escolha e possibilita as reconstruções de imagens tridimensionais e em outros planos anatômicos, como sagital e coronal. Todas as imagens foram adquiridas e avaliadas em filtro e janela para tecido ósseo. Observaram-se diferenças anatômicas e as particularidades normais das vértebras, principalmente da região occipitoatlantoaxial, a qual apresenta maior incidência de alterações.

In search of clinical truths: equine and comparative studies of anatomy

The importance of correlating anatomical studies with diagnostic and therapeutic approaches in practice has long been recognised. Such studies in the horse have, until recently, lagged behind this discipline in human medicine and surgery. Clinical techniques by which this correlation is achieved include radiography, ultrasound, computed tomography and magnetic resonance imaging. This review presents published literature on the subject and, in addition, describes the part played by plastination, a recently developed technique for the preservation of biological specimens. In this, tissue fluids and part of the lipids are replaced by certain polymers yielding specimens that can be handled without gloves, do not smell or decay, and even retain microscopic properties of the original sample. The technique has proved to be a useful tool to correct previously presented anatomical descriptions and is one now favoured by human surgeons. Studies of the horse employing this technique include those of the temporomandibular joint and tarsus. The aim of the review is to stimulate further correlations of anatomical structure and equine medical and surgical procedures, thereby advancing knowledge and understanding in practice and teaching.

Imaging features of discospondylitis in two horses

Two horses with discospondylitis are described with emphasis on the imaging modalities used and their contribution to the final diagnosis and outcome. Radiographic findings were vertebral endplate lysis with sclerosis in both horses, with additional vertebral subluxation and ventral spondylosis in one horse. Ultrasonographic findings included vertebral malalignment and obliteration of the intervertebral disc by spondylotic bone in one horse and irregular endplates, a widened disc space, a hypoechoic paravertebral abscess and hypoechoic, atrophic adjacent musculature with loss of linear fiber pattern in the other horse. Bone scintigraphy excluded additional affected sites. A systematic approach is recommended when performing an ultrasound examination of the spine.

Accuracy of ultrasound-guided intra-articular injection of cervical facet joints in horses: a cadaveric study

REASONS FOR PERFORMING STUDY

Intra-articular facet joint injection is an established diagnostic procedure in human medicine but there are no reports on its reliability in equine practice.

OBJECTIVES

To investigate the accuracy of ultrasound-guided intra-articular injections of the cervical facet joints and to estimate factors influencing the accuracy.

METHODS

Sixty injections with blue dye were performed on the facet joints between 2nd and 7th cervical vertebra (C2-C7) on horses subjected to euthanasia for nonorthopaedic reasons. The facet joints were subsequently dissected to verify accuracy of deposition.

RESULTS

Seventy-two percent of the injections were found to be intra-articular, 17% were intracapsular and a total of 98% were within 1 mm of the joint capsule. There was a marked effect of gained experience (P < 0.01), but not of other factors tested.

CONCLUSIONS AND POTENTIAL RELEVANCE

The results of the present study do not translate directly to injections performed in live horses, but they indicate that the method can be applied as a diagnostic as well as therapeutic procedure in C2 to C7 and that is advisable to practise injections on cadaver specimens before applying the technique.