Percutaneous full endoscopic foraminotomy for treatment of cervical spinal nerve compression in horses using a uniportal approach: Feasibility study.

BACKGROUND: Cervical spinal nerve insult can be a sequel of osteoarthropathy in horses due to enlargement of the articular processes (AP). OBJECTIVES: To describe the percutaneous endoscopic cervical foraminotomy procedure in horses. STUDY DESIGN: Ex vivo experimental study and clinical case report. METHODS: The technique was performed in three equine cadavers and in two clinical cases with history of forelimb lameness located in the caudal cervical region. Briefly, the horse was positioned in lateral recumbency, with the affected AP joint uppermost. Under fluoroscopic guidance, the endoscopic instruments (Ø 6.9 mm, length 207 mm, 25° angle of vision) were positioned at the dorsal bony margin of the intervertebral foramen (IVF). The bone was freed from soft tissues and removed using diamond various burrs, hence widening the IVF. The bone drilling was continued until the medial cortical surface of the caudal AP was removed. Thereafter, the endoscope was removed and the skin portal was closed. RESULTS: The average of operation time in clinical cases was 98 ± 24 min. The horses recovered smoothly from the operation. At 12-month follow-up, the clinical signs had resolved completely without recurrence. MAIN LIMITATION: Small number of clinical cases and absence of post-mortem examination or histopathology performed in the cadaver study to assess possible iatrogenic injuries. CONCLUSION: Cervical spinal nerve decompression via minimal invasive foraminotomy is feasible in horses. More research is required before this procedure can be recommended in clinical cases.

The impact of different bone tracers and acquisition times on image quality of equine bone scintigraphy.

The impact of different acquisition times (AqT) and technetium-99 m-labeled (99m Tc) diphosphonates on the image quality of bone scintigraphy is poorly documented in horses. The aim of this prospective experimental study was to evaluate the impact of varying 99m Tc-disphosphonates and AqT on semiquantitative and qualitative image parameters of bone scintigraphy in horses. Twenty-four horses undergoing bone scintigraphy were divided equally and randomly into methylene- (MDP), hydroxymethylene- (HDP), and dicarboxypropane diphosphonate (DPD) groups. Lateral scintigraphic images of the antebrachium were obtained 3 h post 99m TC-diphosphonate injection using three AqT (60, 90, 120 s). The images were analyzed semiquantitatively using the bone-soft tissue ratio (B:ST), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image contrast. Furthermore, a blinded qualitative analysis was performed using a visual grading analysis. The results showed that DPD images had a significantly higher B:ST ratio than MDP images (P < .01) but not HDP images in all AqT (P > .08). However, DPD and HPD images acquired at 60 s had significantly higher CNR (P < .05) than those acquired at 90 and 120 s. The qualitative analysis revealed no significant differences between 99m Tc-diphosphonates at AqT 60 and 90 s. However, MDP images acquired at 120 s had significantly lower image quality compared to DPD and HDP (P = .01 and .03, respectively). In conclusion, the bone tracers affected the semiquantitative image parameters but not the qualitative analysis findings. Increasing AqT did not necessarily improve the image quality. Therefore, decreasing the AqT enabled a reduction in personnel radiation exposure.

Effectiveness of Platelet-Rich Plasma and Bone Marrow Aspirate Concentrate as Treatments for Chronic Hindlimb Proximal Suspensory Desmopathy.

This retrospective study aimed to evaluate the clinical effect of bone marrow aspirate concentrate (BMAC) and leukocyte rich PRP (LR-PRP) compared to horses undergoing controlled exercise alone in horses with >3 months proximal suspensory desmopathy in hindlimbs (HPSD). Nighty-three horses were divided into three groups according to the treatment: a control (n = 22), LR-PRP (n = 46), and BMAC (n = 25) group. Lameness and ultrasound scores were recorded before treatment (T0) and at 6 months (T1) post-treatment. Records horses considered sound at evaluation and level of performance were additionally registered at 12 months (T2) and 18 months (T3) after treatment. The BMAC cytology profiles from 22 horses were also analysed and compared to clinical outcomes. The results at T1 showed that 9% (2/22) of the horses in the control group were sound compared to 59% (25/46) and 84% (21/25) in the LR-PRP and BMAC groups, respectively. Additionally, ultrasound scores at T1 in the BMAC and LR-PRP groups were improved in comparison with the control group (p = 0.02). At T2, 68% of the horses in the BMAC group and 39% of the horses in the LR-PRP group had returned to the previous performance level. At T3, a significantly higher percentage of horses in the LR-PRP (43%) and BMAC (72%) group were sound when compared to the control (4.6%) group (p = 0.02). Similarly, at T3, significantly more horses of the BMAC (16/25) and of the LR-PRP (15/46) group had returned to the previous or a higher performance level compared to the control (1/22) group (p = 0.01). No correlation was found between long-term clinical outcome and cytology profiles in the BMAC group. In conclusion, long-term outcomes of treatment with LR-PRP or BMAC are significantly better than conventional treatment of the hindlimb chronic PSD in horses. Additionally, BMAC yielded better lameness scores than LR-PRP at short- and long-term follow-up.

Furosemide administration onehour before bone scintigraphy examination in horses does not improve the image quality or reduce the radiation dose rate.

This prospective, cross-sectional, pilot study aimed to investigate the effects of furosemide as a diuretic on the image quality of bone scintigraphy performed using 99m Tc-HDP and to investigate the impact of furosemide on the radiation dose rate. Thirty-one horses undergoing bone scintigraphy were included. The horses were divided into the control (n = 14) and furosemide group (n = 17), which received 1 mg/kg furosemide intravenously 1 h post 99m Tc-HDP administration. The image quality was assessed subjectively and semi-quantitatively. The bone-to-soft tissue (B:S) ratio was calculated from the counts per pixel of regions of interest (ROI) positioned over the left radial diaphysis (bone ROI) and its caudal soft tissue area (soft tissue ROI). The radiation rate dose (µSv/h) of both groups was measured at 0, 3, 6, 12, 18, and 24 h post 99m Tc-HDP administration at a distance of 0, 30, and 100 cm from the head, kidney, and pelvis. The results showed no significant differences in the B:S ratio or the radiation dose rate observed between the groups. However, the radiation dose rate decreased by 56% at 3 h post 99m Tc-HDP administration and keeping a distance of 30 cm reduced the radiation dose rate by 65%. Administering furosemide does not improve the image quality or reduce the radiation dose rate. The authors recommend commencing with bone scintigraphy 3 h post 99m Tc-HDP administration and keeping at least a distance of 30 cm from the horse to reduce the staff radiation dose.

Computed Tomography and Magnetic Resonance Imaging of an Epidermoid Cyst in a Foot of a Horse.

An 18-year-old Quarter Horse mare was evaluated because of moderate left forelimb lameness of 4 weeks' duration. The clinical evaluation and diagnostic perineural analgesia localized the lameness to the distal portion of the left forelimb. There was swelling on the dorsal and lateral aspect of the coronary band. Radiography, ultrasound, magnetic resonance imaging, and computed tomography of the foot revealed circumscribed well-capsulated soft tissue mass causing a focal deformation of the dorsolateral border of the middle phalanx. The treatment aimed to remove the mass surgically and stabilized the interphalangeal joint, but the owner elected human euthanasia before treatment attempt. Histopathology diagnosis was an epidermoid cyst, which was characterized by multilayers of keratin surrounded by stratified squamous epithelium. Although rare, an epidermoid cyst should be considered as a differential diagnosis for space-occupying mass in horses' foot that develops chronic lameness after trauma. This report describes the multimodality appearance of the epidermoid cyst.

Scintigraphic evaluation of cheek teeth in clinically sound horses.

Dental disorders are one of the top-ranking clinical domains in equine practice. Scintigraphy has emerged as a useful diagnostic imaging modality for equine dental diseases. There is a paucity of the normal scintigraphic uptake and its correlation with age. This prospective, cross-sectional, descriptive and pilot-designed study aimed to describe the radioisotope uptake (RU) patterns of the reserved crown and periodontal bone of the maxillary and mandibular cheek teeth (CT) in clinically sound horses and to evaluate the age effect on RU. For this purpose, 60 horses that underwent a bone scintigraphy for reason unrelated to head were included and divided equally into four age groups. Regions of interests (ROIs) were positioned around alveolar and periodontal bone of each maxillary and mandibular CT including their reserve crown, and a reference ROI positioned at the mandibular ramus. The count per pixel of each ROI was measured using a dedicated software and the RU ratio relative to the reference region was calculated. The results showed that the maxillary and mandibular CT had a standard RU pattern, where it increased from rostral to caudal, and peaked in the middle of dental arcades and decreased slightly towards the last CT. The maxillary CT had a higher RU compared with the mandibular CT, and there was no significant difference in the maxillary and mandibular CT uptake between age groups. This information may aid veterinarians evaluating potentially abnormal dental scintigraphy.

Morphometrical dimensions of the sheep thoracolumbar vertebrae as seen on digitised CT images.

The sheep spine is widely used as a model for preclinical research in human medicine to test new spinal implants and surgical procedures. Therefore, precise morphometric data are needed. The present study aimed to provide computed tomographic (CT) morphometry of sheep thoracolumbar spine. Five adult normal Merino sheep were included in this study. Sheep were anaesthetised and positioned in sternal recumbency. Subsequently, transverse and sagittal images were obtained using a multi-detector-row helical CT scanner. Measurements of the vertebral bodies, pedicles, intervertebral disc and transverse processes were performed with dedicated software. Vertebral bodies and the spinal canal were wider than they were deep, most obviously in the lumbar vertebrae. The intervertebral discs were as much as 57.4% thicker in the lumbar than in the thoracic spine. The pedicles were higher and longer than they were wide over the entire thoracolumbar spine. In conclusion, the generated data can serve as a CT reference for the ovine thoracolumbar spine and may be helpful in using sheep spine as a model for human spinal research.

Is sheep lumbar spine a suitable alternative model for human spinal researches? Morphometrical comparison study.

Sheep are commonly used as a model for human spinal orthopaedic research due to their similarity in morphological and biomechanical features. This study aimed to document the volumes of vertebral bodies and compare the generated results as well as morphometry of the sheep lumbar spine to human published data. For this purpose, computed tomography scans were carried out on five adult Merino sheep under general anaesthesia. Transverse 5 mm thick images were acquired from L1 to L6 using a multi-detector-row helical CT scanner. Volume measurements were performed with dedicated software. Four spinal indices and Pavlov's ratio were calculated. Thereafter, the generated data were compared to published literature on humans. The mean vertebral body volume showed an increase towards the caudal vertebrae, but there were no significant differences between the vertebral levels (P>0.05). Compared to humans, sheep vertebral body volumes were 48.6% smaller. The comparison of absolute values between both species revealed that sheep had smaller, longer and narrower vertebral bodies, thinner intervertebral discs, narrower spinal canal, longer transverse processes, shorter dorsal spinous processes and narrower, higher pedicles with more lateral angulations. The comparison of the spinal indices showed a good similarity to human in terms of the vertebral endplates and spinal canal. The results of this study may be helpful for using the sheep as a model for human orthopaedic spinal research if anatomical differences are taken into account.