Articular Process Joints Research Articles

Advances in diagnosis and imaging of cervical dysfunction in the sports horse

Cervical imaging provides an abundance of data. It is important not to lose sight of the horse and to determine what clinical relevance these findings have. Good clinical examination, in combination with knowledge of functional anatomy and biomechanics, are essential in anticipation of more research which will allow veterinarians to work in a more evidence-based manner. The location of cervical pain can be pinpointed to a single or multiple locations with an extensive history, static observation, general palpation, motion evaluation, specific palpation and dynamic evaluation. The whole body should be evaluated. The majority of cervical pathology (80%) is located in the caudal cervical area (C5–T1). Radiography of this region can be improved with good quality equipment, collimation, correct positioning of the horse and a correct distance between generator and plate. Radiography and ultrasonography may underestimate cervical pathology. Computed tomography is the preferred method of imaging but may lead to over interpretation. The most common finding is narrowing of the intervertebral foramen because of enlargement of the articular process joint(s). More than one location with abnormalities is often identified.

Short-term effectiveness of unilateral biportal endoscopy technique in treatment of lumbar lateral saphenous fossa combined with intervertebral foramina stenosis via contralateral sublaminar approach

To investigate the short-term effectiveness of unilateral biportal endoscopy (UBE) in treatment of lumbar lateral saphenous fossa combined with intervertebral foramina stenosis via contralateral sublaminar approach. A clinical data of 15 patients with lumbar lateral saphenous fossa combined with intervertebral foramina stenosis, who were admitted between September 2021 and December 2023 and met selective criteria, was retrospectively analyzed. There were 5 males and 10 females with an average age of 70.3 years (range, 46-83 years). Surgical segment was L 4, 5 in 12 cases and L 5, S 1 in 3 cases. The disease duration was 12-30 months (mean, 18.7 months). All patients were treated by UBE via contralateral sublaminar approach. The operation time, intraoperative blood loss, postoperative hospital stay, and the occurrence of complications were recorded. The visual analogue scale (VAS) score was used to evaluate the degree of lower back and leg pain before and after operation; the Japanese Orthopaedic Association (JOA) score and the Oswestry disability index (ODI) were used to evaluate the lumbar function; and the clinical outcome was evaluated using the MacNab criteria at 6 months after operation. Postoperative MRI and CT were taken to observe whether the lateral saphenous fossa and intervertebral foramen stenosis were removed or not, and the cross-sectional area of the spinal canal (CSA-SC), cross-sectional area of the intervertebral foramen (CSA-IVF), and cross-sectional area of the facet joint (CSA-FJ) were measured. The operation time was 55-200 minutes (mean, 127.5 minutes); the intraoperative blood loss was 10-50 mL (mean, 27.3 mL); the length of postoperative hospital stay was 3-12 days (mean, 6.8 days). All patients were followed up 6-12 months (mean, 8.9 months). At 1 day, 1 month, 3 months, and 6 months after operation, the VAS scores of low back and leg pain and ODI scores after operation were significantly lower than preoperative scores and showed a gradual decrease with time; the JOA scores showed a gradual increase with time; the differences in the above indexes between different time points were significant ( P<0.05). The clinical outcome was rated as excellent in 10 cases, good in 4 cases, and poor in 1 case according to the MacNab criteria at 6 months after operation, with an excellent and good rate of 93.33%. Imaging review showed that the compression on the lateral saphenous fossa and intervertebral foramina had been significantly relieved, and the affected articular process joint was preserved to the maximum extent; the CSA-SC and CSA-IVF at 3 days after operation significantly increased compared to the preoperative values ( P<0.05), and the CSA-FJ significantly reduced ( P<0.05). The UBE via contralateral sublaminar approach can effectively reduce pressure in the lateral saphenous fossa and the intervertebral foramina of the same segment while preserving the bilateral articular process joints. The short-term effectiveness is good and it is expected to avoid fusion surgery caused by iatrogenic instability of the lumbar spine. However, further follow-up is needed to clarify the mid- and long-term effectiveness.

Ultrasound-guided caudal cervical articular process arthrocentesis is accurate in live horses with and without arthropathy.

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. 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. Retrospective case study. 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. 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. Retrospective study design. Intra-articular ultrasound-guided caudal CAPJ injections using a modified cranial approach can be performed accurately in live horses with and without CAPJ arthropathy.

Primary phenotypic features associated with caudal neck pathology in warmblood horses.

Detailed descriptions of clinical signs associated with radiological findings of the caudal cervical vertebral column are not available. Describe the clinical features associated with neck pain or stiffness, neck-related thoracic limb lameness, proprioceptive ataxia consistent with a cervicothoracic spinal cord or nerve lesion, and their frequency of occurrence compared with control horses. A total of 223 Warmblood horses. Case-control study. Controls and cases were recruited prospectively. All horses underwent predetermined lameness and neurologic examinations. The frequency of occurrence of each clinical feature was compared between cases and controls and relative risk (RR) were calculated. Ninety-six cases and 127 controls were included. Forty-seven (49%) of the cases were classified as neurologic, 31 (32.3%) had thoracic limb lameness, and 18 (18.7%) had neck stiffness or pain or both. Focal caudal cervical muscle atrophy (46, 47.9%), hypoesthesia (38, 39.6%), patchy sweating (16, 16.7%), hyperesthesia (11, 11.5%), and pain upon firm pressure applied over the caudal cervical articular process joints and transverse processes (58, 60.4%) were only observed in cases (P < .001). Sideways flexion of the neck was restricted in a higher proportion of cases (47/96, 49%) compared with controls (40/127, 31.8%; P = .009, RR 1.5). Hopping-type thoracic limb lameness was only observed in cases, (30, 31.6%). Deterioration in lameness after diagnostic anesthesia occurred in 13/31 (41.9%) cases. Systematic clinical evaluation using the methods described should enable clinical differentiation between horses with caudal cervical lesions and horses with other causes of gait abnormalities.

Effectiveness of unilateral biportal endoscopy combined with percutaneous pedicle screw fixation in treatment of lumbar burst fractures with neurological symptoms

To evaluate the effectiveness of spinal canal decompression assisted by unilateral biportal endoscopy (UBE) and percutaneous uniplanar pedicle screw internal fixation in the treatment of lumbar burst fractures with neurological symptoms. Between June 2021 and December 2022, 10 patients with single level lumbar burst fracture with neurological symptoms were treated with spinal canal decompression assisted by UBE and percutaneous uniplanar pedicle screw internal fixation. There were 7 males and 3 females with an average age of 43.1 years (range, 21-57 years). The injured vertebrae located at L 1 in 2 cases, L 2 in 4 cases, L 3 in 3 cases, and L 4 in 1 case. There were 7 cases of AO type A3 fractures and 3 cases of AO type A4 fractures. The total operation time, the time of operation under endoscopy, and complications were recorded. Pre- and post-operative visual analogue scale (VAS) score and American Spinal Injury Association (ASIA) scale (grading A-E corresponding to assigning 1-5 points for statistical analysis) were used to evaluate effectiveness. X-ray film and CT were performed to observe the fracture healing, and the ratio of anterior vertebral body height, Cobb angle, and rate of spinal canal invasion were measured to evaluate the reduction of fracture. All operations was successfully completed, and the spinal canal decompression and the bone fragment in spinal canal reduction completed under the endoscopy. Total operation time was 119 minutes on average (range, 95-150 minutes), and the time of operation under endoscopy was 46 minutes on average (range, 35-55 minutes). There was no complication such as dural sac, nerve root, or blood vessel injury during operation. All incisions healed by first intention. All patients were followed up 18.7 months on average (range, 10-28 months). The VAS score after operation significantly decreased when compared with that before operation ( P<0.05), and further improved at last follow-up ( P<0.05). The ASIA scale after operation significantly improved when compared with that before operation ( P<0.05), and there was no significant difference ( P>0.05) in the ASIA scale between at 1 week after operation and at last follow-up. The imaging examination showed that the screw position was good and the articular process joint was preserved. During follow-up, there was no loosening, fracture, or fixation failure of the internal fixation. The ratio of anterior vertebral body height and Cobb angle significantly improved, the rate of spinal canal invasion significantly decreased after operation ( P<0.05), and without significant loss of correction during the follow-up ( P>0.05). Spinal canal decompression assisted by UBE and percutaneous uniplanar pedicle screw fixation is a feasible minimally invasive treatment for lumbar burst fractures with neurological symptoms, which can effectively restore the vertebral body sequence, as well as relieve the compression of spinal canal, and improve the neurological function.

Research into the anatomy of the subaxial cervical pedicle for ensuring screw insertion safety.

The study aimed to determine the optimal entry points and trajectories for posterior subaxial cervical pedicle screw (CPS) fixation. Computed tomography (CT) and Mimics software were used to evaluate the subaxial cervical pedicle in 42 cervical spine CT scans. The width of the cervical pedicle was measured and compared at medial angulations of 30°, 35°, 40°, 45°, 50°, 55°, and 60° relative to the midline sagittal plane. Based on an observational examination of the positions of all cervical 3-dimensional models and screws, the proposed entry point for C3-7 CPS was analyzed. Although the variations in C3-6 pedicle width (PW) among 45°, 50°, and 55° were not statistically significant, they were significantly larger than the differences among 30°, 35°, 40°, and 60° angles (P < .05). The differences in C7 PW between the 30°, 35°, 40°, and 45° angles were not statistically different even though the 30°, 35°, 40°, and 45° angles were significantly bigger. (P < .05). The proposed entry point for C3-7 CPS was below the junction of the lateral and lower borders of the superior articular process joint surface. The entry point for C3-7 levels was below the junction of the lateral and lower borders of the superior articular process joint surface. The optimal medial angulation for the posterior C3-6 CPS was 45°-55° and that for the posterior C7 CPS was 30°-45°. The sagittal angle of the posterior C3-7 CPS was parallel to the corresponding upper endplate.

Facet joint disorders: from diagnosis to treatment.

One of the most common sources of spinal pain syndromes is the facet joints. Cervical, thoracic, and lumbar facet joint pain syndromes comprise 55%, 42%, and 31% of chronic spinal pain syndromes, respectively. Common facet joint disorders are degenerative disorders, such as osteoarthritis, hypertrophied superior articular process, and facet joint cysts; septic arthritis; systemic and metabolic disorders, such as ankylosing spondylitis or gout; and traumatic dislocations. The facet pain syndrome from osteoarthritis is suspected from a patient's history (referred pain pattern) and physical examination (tenderness). Other facet joint disorders may cause radicular pain if mass effect from a facet joint cyst, hypertrophied superior articular process, or tumors compress the dorsal root ganglion. However, a high degree of morphological change does not always provoke pain. The superiority of innervating nerve block or direct joint injection for diagnosis and treatment is still a controversy. Treatment includes facet joint injection in facet joint osteoarthritis or whiplash injury provoking referred pain or decompression in mass effect in cases of hypertrophied superior articular process or facet joint cyst eliciting radicular pain. In addition, septic arthritis is treated using a proper antibiotic, based on infected tissue or blood culture. This review describes the diagnosis and treatment of common facet joint disorders.

Post-mortem ultrasonographic and computed tomographic features of the anatomical variations and acquired pathological bony changes of the lumbosacroiliac region in a mixed population of horses.

Transrectal ultrasonography is the best technique for evaluating the ventral aspect of the lumbosacral and sacroiliac regions yet this diagnostic technique does not always lead to a final diagnosis of back pain in horses. To describe anatomical variations and acquired pathological bony changes (APBCs) in the lumbosacral and sacroiliac regions detected by ultrasonography (US) and computed tomography (CT) examinations on specimens. We hypothesised that age, body mass, previous use and anatomical variations may be correlated with the presence and/or severity of APBCs. Descriptive cadaver study. Lumbosacroiliac specimens were obtained from 51 horses that died or were euthanised for reasons other than the study and underwent US and CT examinations post-mortem. Forty-two specimens were analysed. The most prevalent lumbosacral disc morphology was type 2 (21/42), and protrusions were found in 15/42 specimens. Abnormal echogenicity of the L5-L6 and lumbosacral discs was detected in 11/42 and 30/42 specimens, respectively. Abnormalities in the size of the L5-L6 disc were found in 10/42 specimens and correlated with promontorium localisation (Cramér's V coefficient [V] = 0.42) and lumbosacral disc morphology (type 1: V = 0.41; type 5: V = 0.69). The most prevalent orientation of the L6 spinous process (SP) was convergent (24/42). The promontoria were mostly located between L6 and S1 (36/42). Lumbosacral spondylosis was detected in 24/42 specimens and spondylolisthesis in one. Age was associated with the severity of APBCs in the sacroiliac joints, lumbosacral intertransverse joints, articular process joints, spondylosis and L6 or S1 bone plate irregularities. Lumbosacral spondylosis or L6 extremitas caudalis irregularity was associated with lumbosacral angulation, variability in the size of the L5-L6 disc and localisation of the promontorium, L6 SP orientation and L6 extremitas caudalis irregularity with abnormal echogenicity of the LS disc. Lack of information on clinical signs. High variability and prevalence of the anatomical variations and APBCs in the lumbosacroiliac region were observed, and correlations between some anatomical variations and APBCs and between APBCs and age were reported.

Comparison of ultrasonographic and computed tomographic imaging of equine thoracolumbar articular process joints.

Osteoarthritis of the equine thoracolumbar articular process joints (APJs) has been linked to back pain. Changes are commonly diagnosed through nuclear scintigraphy, radiography and ultrasonography (US). (1) To assess the agreement of APJ grades between US and computed tomography (CT) images; (2) to assess the effect of location on the agreement of APJ grades between US and CT images. It was hypothesised that: (1) Periarticular modelling and modification of the joint space would have the highest and lowest agreement between US and CT images, respectively; (2) Caudal thoracolumbar APJ grades would have higher agreement between US and CT images than mid thoracic APJs. Comparative diagnostic imaging study using cadaveric specimens. Disarticulated thoracolumbar spines of six equids euthanised for reasons unrelated to back pain, underwent US and CT examination of the APJs. Images were assessed for periarticular modelling, modification of the joint space and enlargement of the APJ. Intra-observer, inter-modality and inter-observer agreement using multilevel weighted kappa statistics to evaluate the effects of location, US/CT characteristic and their interaction. Intra-observer agreement of US and CT grades ranged from moderate to perfect. Between T15 and L1, inter-modality agreement (CT vs. US) for periarticular modelling was moderate, and fair for enlargement and modification of the joint space. Inter-observer agreement (US vs. US) of periarticular modelling was substantial between T15 and L1, moderate between L1 and L5 and fair between T10 and T15. Wide confidence intervals (CIs) seen for most grades apart from inter-observer grades of periarticular modelling at T15-L5, introducing a degree of uncertainty into the results. Large prevalence index influenced kappa values, small sample size. Good inter-observer (US vs. US) and inter-modality (CT vs. US) agreement of caudal thoracolumbar APJ periarticular modelling. This US characteristic provides a measure of bone change, therefore supporting the use of diagnostic ultrasound. Inter-modality CIs were wide, highlighting the study and imaging modality limitations.

Survey of equine veterinarians regarding primary equine back pain in the United States.

Back pain is a common complaint, clinical finding and performance limiting factor in sport horses. This study sought to gather current veterinary trends in the diagnosis, treatment and management of primary equine back pain in the United States. A 22 question survey was distributed electronically to equine practitioners through AAEP and ACVSMR listservs and through closed social media groups. The survey was open from April 20, 2022 to July 5, 2022. Responses were analyzed using Microsoft excel pivot tables. Ninety-seven survey responses were obtained and analyzed. Respondents reported the clinical signs most frequently relayed to them by the owner/rider/trainer of horses diagnosed with primary back pain were behavioral issues and poor performance. Most common diagnostic tests reported were radiography of the spinous processes, thoraco-lumbar vertebral bodies, and transcutaneous ultrasound of the thoraco-lumbar region. Most common pathologies reported were impinging dorsal spinous processes, degenerative sacro-iliac joint disease, and osteoarthritis in lumbar or thoracic articular process joints. In regards to impinging spinous process ("kissing spine") treatments, 72.2% of respondents recommended surgery only after non-surgical treatments failed, and 14.6% of respondents never recommended surgery. The majority (82%) of respondents reported some level of improvement in clinical signs of primary back pain with rehabilitation alone. To date, there has been no consensus or discussion about common abnormalities, diagnostic tests, treatments or management options for primary equine back pain in the United States. Results of this survey are a starting point showing current trends in diagnosis, treatment and management of primary equine back pain among equine practitioners in the United States showing 82% of practitioners using rehabilitation as a component of treatment.

Shapes of cervical articular process joints and association with histological evidence of osteochondrosis in Warmblood foals: A post-mortem study.

Osteochondrosis dissecans (OCD) of articular process joints (APJs) is involved in cervical vertebral compressive myelopathy (CVM). Biomechanical forces, important in development of OCD, depend on joint conformation. Oval and flat APJ surfaces are considered normal. To identify and grade gross shape variation of cervical and cranial thoracic APJ surfaces and determine association with histological evidence of osteochondrosis. Case series. Eight hundred and four cervical and cranial thoracic APJ surfaces of 30 foals were evaluated for shape(s) and grades, and were correlated with osteochondrosis. Three top view shapes (oval, pointed, elongated) and seven lateral view shapes (flat, convex, concave, stepped, bevelled, folded edge, raised edge) were regularly encountered. The oval top view shape was most common. Flat and bevelled were the most common lateral view shapes. General shape grade of caudal articular surfaces was significantly higher than of cranial surfaces. The combinations of an oval top view shape and the lateral view shapes folded edge, concave, or flat with additional raised edge and/or folded edge (flat +), were more likely to have OC than oval with convex, bevelled or flat lateral view shapes (normal vs. oval and folded, odds ratio [OR] 2.49 [95% confidence intervals (CIs) 1.13-5.67]; normal vs. oval and flat +, OR 2.77 [95% CI 1.15-6.85]; oval and convex vs. oval and folded, OR 3.20 [95% CI 1.35-8.20]; oval and convex vs. oval and flat +, OR 3.56 [95% CI 1.43-9.54]; oval and bevelled vs. oval and concave, OR 2.02 [95% CI 1.14-3.60]; oval and bevelled vs. oval and folded, OR 3.50 [95% CI 1.91-6.60]; oval and bevelled vs. oval and flat +, OR 3.90 [95% CI 2.00-7.70]). Most foals (21/30) were less than 1 month old. Lack of observer reliability scores for shape and shape grade. APJs shape might contribute to CVM by increased likelihood to have OC.

Interobserver agreement of lateral and oblique radiography and standing cone beam CT of the caudal cervical articular process joints of horses.

Caudal cervical articular process joint osteoarthritis (CAPJ OA) leads to career-altering clinical signs in the horse. Oblique radiographs and standing cone beam computed tomography (CBCT) facilitate the assessment of this area, however, the variability of interpretation of these images is currently unknown. This retrospective, secondary analysis, methods comparison study investigated interobserver agreement between clinicians and modality in grades of CAPJ OA on lateral and oblique radiographs and CBCT. We hypothesized that agreement between clinicians' grades of CAPJ OA would be lowest for oblique radiographs and highest for CBCT, and agreement between grades of CAPJ OA would be low for all pairs of modalities. Horses underwent lateral and oblique radiography and CBCT of the CAPJs of C5-C6 and C6-C7. Radiographs and CBCT images were graded retrospectively by four blinded clinicians using 3-point scales. Cohen's kappa analysis was used to evaluate interobserver agreement between grades of CAPJ OA, and agreement between grades of CAPJ OA between different modalities was explored using kappa-weighted analysis. Agreement between clinicians' grades of CAPJ OA was moderate for lateral radiographs (0.49), and fair for oblique radiographs (0.23) and CBCT (0.36). For all modalities, agreement was slight to fair between clinicians for CAPJs with grade 1 (normal, 0.21-0.32) or 2 (mild, 0.13-0.36) CAPJ OA, and moderate to substantial for grade 3 (moderate to severe, 0.45-0.77) CAPJ OA. Agreement between grades of CAPJ OA was fair for all pairs of modalities. This study provides important information regarding the inconsistency of interpretation of mild CAPJ OA on radiographs and CBCT amongst clinicians.

Age and sex correlate with bony changes and anatomic variations of the lumbosacroiliac region of the vertebral column in a mixed population of horses.

To provide a postmortem description of anatomic variations and changes of the lumbosacroiliac region in horses. The authors hypothesized that lesion severity would increase with age and body weight and correlate to anatomic variations. Lumbosacroiliac vertebral specimens from 38 horses (mean age, 16 years; range, 5 to 30 years) that died or were euthanized for reasons unrelated to the study between November 2019 and October 2021. The lumbosacroiliac region of the vertebral column was removed from each cadaver. After dissection, disarticulation, and boiling, the anatomic specimens were examined for anatomic variations and osseous changes of the articular process joints (APJs), intertransverse joints (ITJs), and sacroiliac joints (SIJs). The lengths of L6-S1 intertransverse articular surfaces were measured and their ratios calculated. Descriptive statistics were obtained, and the χ2 test was used to assess differences in anatomic variations and abnormal changes of the APJs, ITJs, and SIJs. The most common anatomic variation was a sacrum-like shape of the transverse processes of L6 (29/38 [76%]) and converging orientation of dorsal spinous process of L6 (33/38 [87%]). The highest prevalence of bony changes was detected at L5-L6 (right, 34/38 [89%]; left, 33/38 [87%]) and L6-S1 APJs (right, 38/38 [100%]; left, 37/38 [97%]) and at SIJs (right, 32/38 [86%]; left, 31/38 [82%]). The shape of L6 transverse processes differed between breed (P = .01) and was associated with presence of L4-L5 ITJs (P < .01). Age and sex were associated with changes of the sacral dorsal spinous processes, ITJs, and APJs. The clinical significance of these findings could not be confirmed based on the study limitations.

Imaging the equine neck

The equine cervical spine is commonly implicated as the cause of ataxia, proprioceptive reflex deficits and potentially lameness. The cervical spine can be affected by a variety of conditions, including cervical vertebral malformation, articular process joint degenerative joint disease, congenital malformations, fractures and less frequently neoplasia. Surface palpation can only provide minimal diagnostic information, and imaging is therefore typically required. Radiography provides the mainstay of front-line imaging, with the use of laterolateral and oblique projections now commonplace. Advanced imaging options, furthered by the availability of large-bore computed tomography (CT) units, are revolutionising the ability to assess the neck; however, further work is required to fully validate CT myelography as a stand-alone technique to diagnose spinal cord compression. This may have potential to become a gold standard imaging test of the future.

EquineReview

Introduction: This edition of the Equine Review looks at recent papers on osteochondral fragmentation and surgical removal of intra-articular bodies from the cervical articular process joints, and the effect of bit chewing on gastrointestinal transit time in clinically normal horses.

Dynamic three-dimensional computed tomographic imaging facilitates evaluation of the equine cervical articular process joint in motion.

Dynamic computed tomography (CT) imaging has been introduced in human orthopaedics and is continuing to gain popularity. With dynamic CT, video sequences of anatomical structures can be evaluated in motion. To investigate the feasibility of dynamic CT for diagnostic imaging of the equine cervical articular process joints (APJs) and to give a detailed description of the APJ movement pattern. Descriptive cadaver imaging. Cervical specimens of twelve Warmblood horses were included. A custom-made motorised testing device was used to position and manipulate the neck specimens and perform dynamic 2D and 3D CT imaging. Images were obtained with a 320-detector-row CT scanner with a 160mm wide-area (2D) solid-state detector design that allows image acquisition of a volumetric axial length of 160mm without moving the CT couch. Dynamic videos were acquired and divided into four phases of movement. Three blinded observers used a subjective scale of 1 (excellent) to 4 (poor) to grade the overall image quality in each phases of motion cycle. With an overall median score of 1 the image quality, a significantly lower score was observed in the dynamic 3D videos over the four phases by the three observers compared with the 2D videos for both flexion (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P=.007) and extension movement (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P=.008). Median Translational displacement of the APJ surface was significantly greater in flexion than in extension movement (P=.002). The small number of specimens included. Excision of spines and removal of musculature. The study is a first step in the investigation of the potential of dynamic 3D CT in veterinary medicine, a technique that has only begun to be explored and leaves much room for refinement prior to its introduction in routine practice. CT with a detector coverage of 16cm and a rotation speed of 0.32seconds provides high-quality images of moving objects and gives new insight into the movement pattern of equine cervical APJs.

Osteochondrosis and other lesions in all intervertebral, articular process and rib joints from occiput to sacrum in pigs with poor back conformation, and relationship to juvenile kyphosis

BackgroundComputed tomography (CT) is used to evaluate body composition and limb osteochondrosis in selection of breeding boars. Pigs also develop heritably predisposed abnormal curvature of the spine including juvenile kyphosis. It has been suggested that osteochondrosis-like changes cause vertebral wedging and kyphosis, both of which are identifiable by CT. The aim of the current study was to examine the spine from occiput to sacrum to map changes and evaluate relationships, especially whether osteochondrosis caused juvenile kyphosis, in which case CT could be used in selection against it. Whole-body CT scans were collected retrospectively from 37 Landrace or Duroc boars with poor back conformation scores. Spine curvature and vertebral shape were evaluated, and all inter-vertebral, articular process and rib joints from the occiput to the sacrum were assessed for osteochondrosis and other lesions.ResultsTwenty-seven of the 37 (73%) pigs had normal spine curvature, whereas 10/37 (27%) pigs had abnormal curvature and all of them had wedge vertebrae. The 37 pigs had 875 focal lesions in articular process and rib joints, 98.5% of which represented stages of osteochondrosis. Five of the 37 pigs had focal lesions in other parts of vertebrae, mainly consisting of vertebral body osteochondrosis. The 10 pigs with abnormal curvature had 21 wedge vertebrae, comprising 10 vertebrae without focal lesions, six ventral wedge vertebrae with ventral osteochondrosis lesions and five dorsal wedge vertebrae with lesions in the neuro-central synchondrosis, articular process or rib joints.ConclusionsComputed tomography was suited for identification of wedge vertebrae, and kyphosis was due to ventral wedge vertebrae compatible with heritably predisposed vertebral body osteochondrosis. Articular process and rib joint osteochondrosis may represent incidental findings in wedge vertebrae. The role of the neuro-central synchondrosis in the pathogenesis of vertebral wedging warrants further investigation.

Computed tomographic examination of the articular process joints of the cervical spine in warmblood horses: 86 cases (2015-2017).

To describe articular process joints (APJs) of the cervical spine in horses on the basis of CT and to determine whether abnormalities were associated with clinical signs. 86 client-owned warmblood horses. Horses that underwent CT of the cervical spine between January 2015 and January 2017 were eligible for study inclusion. Medical records were reviewed for age, body weight, breed, sex, history, clinical signs, and CT findings. Horses were divided into 3 case groups and 1 control group on the basis of clinical signs. 70 warmblood horses were cases, and 16 were controls. Abnormalities were more frequent from C5 through T1 and were severe in only horses from the case group. Narrowing of the intervertebral foramen was common in horses in the case group (85.7%), often owing to enlarged, misshaped articular processes, followed by degenerative changes, periarticular osteolysis, cyst-like lesions, and fragmentation. High articular process-to-vertebral body (C6) ratio (APBR) and high-grade narrowing of the intervertebral foramen and periarticular osteolysis were noted for horses with forelimb lameness or signs of cervical pain or stiffness. No association was identified between APBR and age or sex. An APBR > 1.5 was found in only horses in the case group, and 32.3% of APJs with APBRs > 1.5 did not have any degenerative changes and periarticular osteolysis. CT was useful to identify abnormalities of the APJs of the cervical spine. An association existed between CT findings and clinical signs. The APJs can be enlarged without concurrent degenerative changes.

Computed tomographic myelography for assessment of the cervical spinal cord in ataxic warmblood horses: 26 cases (2015-2017).

To quantify the degree of dural compression and assess the association between site and direction of compression and articular process (AP) size and degree of dural compression with CT myelography. 26 client-oriented horses with ataxia. Spinal cord-to-dura and AP-to-cross-sectional area of the C6 body ratios (APBRs) were calculated for each noncompressive site and site that had > 50% compression of the subarachnoid space. Site of maximum compression had the largest spinal cord-to-dura ratio. Fisher exact test and linear regression analyses were used to assess the association between site and direction of compression and mean or maximum APBR and spinal cord-todura ratio, respectively. Mean ± SD spinal cord-to-dura ratio was 0.31 ± 0.044 (range, 0.20 to 0.41) for noncompressive sites and 0.44 ± 0.078 (0.29 to 0.60) for sites of maximum compression. Sites of maximum compression were intervertebral and extra-dural, most frequently at C6 through 7 (n = 10), followed by C3 through 4 (6). Thirteen horses had dorsolateral and lateral compression at the AP joints, secondary to AP (n = 7) or soft tissue proliferation (6). Site significantly affected direction of compression, and directions of compression from occiput through C4 were primarily ventral and lateral, whereas from C6 through T1 were primarily dorsal and dorsolateral. No linear relationship was identified between mean or maximum APBR and spinal cord-to-dura ratio. CT myelography may be useful for examination of horses with suspected cervical compressive myelopathy. Degree of compression can be assessed quantitatively, and site of compression significantly affected direction of compression.

Unilateral degenerative joint disease of a cervical articular process joint between the fourth and fifth cervical vertebrae causing asymmetrical ataxia in a young horse

SummaryA 5‐year‐old horse was examined for investigation of asymmetrical, quadrilateral ataxia and paresis. Clinical examination was unremarkable, and a thorough neurological examination localised the lesion to the cervical spine. Following this, magnetic motor evoked potentials were acquired to allow for latency times to be determined. Abnormal conduction times were found to the right thoracic and right pelvic limbs, confirming that the horse had an asymmetrical cervical spinal myelopathy. Radiographs were acquired to ensure that the horse had no significant pathology which would contraindicate general anaesthesia. There were no abnormalities noted on these, so the horse underwent contrast‐enhanced computed tomography of its cervical spine which revealed enlargement of the right articular process joint between C4 and C5 with dorsolateral impingement of the spinal canal and cord. Due to the poor prognosis for future performance, the horse was subsequently euthanised. A post‐mortem examination confirmed the findings of degenerative joint disease, with some unexpected changes seen on histology of the spinal cord. The unilateral right‐sided compression had caused degenerative changes to ascending and descending tract bilaterally indicating a dynamic component to this lesion, which would be more commonly understood to be static.