Surgical treatment of headshaking by removal of a paracondylar process fragment via modified hyovertebrotomy approach: A detailed anatomical and surgical description in an adult horse.

OBJECTIVE: To describe, in detail, the relevant anatomy and surgical approach to access the paracondylar process (PCP) and report its application in a clinical case of headshaking. ANIMAL: A seven-year-old, mixed breed mare. STUDY DESIGN: Experimental study/case report. METHODS: A seven-year-old mixed breed mare was presented for investigation of acute onset progressing violent headshaking, resulting in the horse falling on multiple occasions. The horse was highly reactive to palpation over the right PCP. Standing computed tomographic (CT) investigation and ultrasonographic examination of the head detected a fracture of the right PCP. Five equine heads of mixed breeds and sizes were dissected to demonstrate the relevant anatomy surrounding the PCP with regard to surgical access. A modified hyovertebrotomy approach was used to remove the fracture fragment under general anesthesia. RESULTS: The anatomy surrounding the PCP was described. The fragment was successfully removed resulting in gradual resolution of clinical signs. The horse recovered well postoperatively and was back into light levels of work with no signs of headshaking present two and a half years following surgery. CONCLUSION: The caudal meningeal artery and vein as well as the glossopharyngeal and hypoglossal nerves are adjacent to the PCP and must be avoided during dissections. The modified hyovertebrotomy approach allows safe surgical access to the PCP. Surgical excision of a PCP fragment can result in complete resolution of clinical signs of headshaking. Computed tomography and ultrasonography are valuable diagnostic tools to identify a fracture of the PCP.

Exceptional Hydrogen Diffusion Rate over Ru Nanoparticle-Doped Polar MgO(111) Surface.

Hydrogen (H) conductivity on oxide-based materials is crucially important in fuel cells and related catalysis. Here, this work measures the diffusion rate of H generated from Ru nanoparticles loaded on polar MgO(111) facet particles under H2 at elevated temperatures without moisture and compares it to conventional nonpolar MgO(110) for the first time by in situ quasielastic neutron scattering (QENS). The QENS reveals an exceptional diffusion rate on the polar facet via a proton (H+ ) hopping mechanism, which is an order of magnitude superior to that of typical H+ -conducting oxides. This work attributes this to the unique atomic arrangement of alternate layers of Mg cations and O anions of the polar MgO(111) where the strong electrostatic field of terminal oxygen anions facilitates protonic migration with a lower degree of local covalency.

Retrospective analysis of oblique and straight distal sesamoidean ligament desmitis in 52 horses.

BACKGROUND: Injuries to the oblique (ODSL) or straight (SDSL) distal sesamoidean ligaments are a recognised cause of distal limb lameness in the horse. However, there are only limited publications addressing common diagnostic features and prognosis. OBJECTIVES: (a) Report findings on ultrasonography and standing low-field magnetic resonance imaging (sMRI) in horses with ODSL or SDSL injury; (b) Identify clinical variables associated with lesion type and (c) Identify factors associated with return to soundness in horses with ODSL or SDSL injury. STUDY DESIGN: Retrospective case series. METHODS: Horses with a primary diagnosis of ODSL or SDSL injury confirmed with a combination of diagnostic analgesia and detection of a lesion on imaging (ultrasonographic ± advanced imaging) were included. Return to soundness and performance follow-up data were obtained. RESULTS: Fifty-one horses were included. SDSL injuries were more common in the forelimb (13/21, 62%), while ODSL injuries had equal frequency in fore- (15/30, 50%) and hindlimbs (15/30, 50%). ODSL injuries were more likely than SDSL injuries to affect the proximal third of the ligament (OR =13; 95% CI 2.3-74.3; p = 0.004) and often presented with periligamentar swelling (20/30;67%) and focal pain (22/28;79%). Lesions were frequently detected using ultrasonography (35/42;83%) and sMRI examination (18/25;72%). Only 27/49 cases (55%) returned to soundness, with only 15/49 (31%) returning to intended use. There were no significant associations between outcome and clinical features or treatment. MAIN LIMITATIONS: There was no comparative "gold standard" to validate lesions such as high-field MRI or histopathology. CONCLUSIONS: In contrast to previous studies, ODSL and SDSL injuries were readily identified ultrasonographically using appropriate views, and with sMRI. Given the limited availability, cost and general anaesthetic risks associated with high-field MRI, more focus should be placed on optimising the ultrasonographic examination. Owners of affected horses should be informed of the guarded prognosis for return to full use.

Ultrasound-guided tenoscopic decompression of digital sheath synoviocoeles in 10 horses.

OBJECTIVE: To report the diagnostic features and clinical outcome of horses with digital flexor tendon sheath (DFTS) synoviocoeles treated tenoscopically under ultrasonographic guidance. STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned horses (n = 10). METHODS: Medical records were searched for horses with lameness localized to the region of the DFTS and clinical evidence of a fluid-filled mass (synoviocoele) associated with the DFTS. Diagnostic imaging and surgical findings, together with long-term outcome, were reported. RESULTS: Lameness and synoviocoeles were unilateral (5 forelimbs, 5 hindlimbs; 3 lateral and 2 medial in both) and located proximal to the palmar/plantar annular ligament. Synoviocoeles had a firm consistency and focal pain with inability to deflate on non-weight-bearing examination. Intrathecal DFTS anesthesia was positive in 7/8 horses in which it was performed, with the remainder localized to the region of the synoviocoele using perineural and/or intralesional anesthesia. Communication between the DFTS and synoviocoele was suspected ultrasonographically in all cases and confirmed on contrast tenography (6/6). Tenoscopic fenestration of the communication between the DFTS and synoviocoele under ultrasonographic guidance, with treatment of concurrent intrathecal injury (4/10), resolved the lameness in all horses re-evaluated by a veterinarian (9/9) and allowed return to full athletic function in all cases at long-term follow up (median 5 years; range 1.25-9 years). CONCLUSION: Tenoscopic decompression was an effective treatment for DFTS synoviocoeles, which, along with treatment of concurrent intrathecal injury, carried an excellent prognosis and avoided the need for resection via an extrasynovial approach.