Anatomy of the congenital calcaneal bursae in the bovine.

OBJECTIVE: The objective of this study was to determine the anatomical relationship of the congenital calcaneal bursae in the bovine, and describe the computed tomography (CT), endoscopic and gross anatomy of these bursae. STUDY DESIGN: Ex vivo experimental. SAMPLE POPULATION: Eighteen clinically normal cadaver bovine hindlimbs. METHODS: Intrasynovial injection of iodinated contrast and methylene blue into the intertendinous calcaneal bursa (ICB) (n = 16) or gastrocnemius calcaneal bursa (GCB) (n = 2). Limbs were imaged post-contrast injection using multidetector CT. Endoscopic examination of the ICB was performed on two randomly selected limbs. All limbs underwent gross anatomical dissection. RESULTS: The anatomy of the congenital calcaneal bursae was consistent between CT imaging, endoscopic examination and gross dissection. The ICB and GCB were two separate synovial structures with no communication in all limbs. The distal and proximal extent of the ICB, defined as the distance from the point of tuber calcanei to the distal/proximal aspect of the ICB, was (median [IQR]) 7.4 (7.4 to 7.8) cm distally and 5.4 (4.7 to 6.0) cm proximally. CONCLUSION: Positive contrast CT and gross anatomical dissection revealed no communication between the congenital calcaneal bursae in any limb. Routine bursoscopy allowed complete endoscopic examination of the ICB. The proximal extent of the ICB is shorter than the distal extent. The use of a collective term for these bursae should be avoided in the bovine, as the ICB and the GCB are two separate synovial structures with no communication. CLINICAL SIGNIFICANCE: Knowledge of distinct anatomy and relationship between the congenital calcaneal bursae in the bovine may facilitate diagnosis and treatment of disorders affecting the region of tuber calcanei, including septic bursitis and osteomyelitis.

Transphyseal screw placement with and without hemicircumferential periosteal transection and elevation for correction of severe bilateral carpal varus deformities in an alpaca cria.

CASE DESCRIPTION: A 2.5-month-old 17.5-kg female alpaca cria was presented for evaluation and treatment of severe bilateral carpal varus deformities. CLINICAL FINDINGS: No lameness was evident at a walk, and neither carpal varus deformity could be corrected by means of manipulation. Radiography revealed severe varus of the left (27°) and right (21°) carpal regions. No additional conformational abnormalities were detected. TREATMENT AND OUTCOME: A single 2.7-mm transphyseal cortical screw was placed in the distolateral aspect of the radius in each limb. On reexamination 8 weeks after screw placement, the left carpal varus deformity had corrected from 27° to 2.6°, and the left transphyseal screw was removed. The right carpal varus deformity had improved but was still present (18°), and hemicircumferential periosteal transection and elevation was performed on the mediodistal aspect of the right radius. Five weeks after the second surgery, the right carpal varus deformity had corrected to 2.4°, and the right transphyseal screw was removed. Six months after the second screw removal, both thoracic limbs remained straight, the cria had a normal gait, and the owner was happy with the cosmetic result. CLINICAL RELEVANCE: Placement of a single transphyseal cortical screw with or without the addition of hemicircumferential periosteal transection and elevation can provide a favorable outcome in skeletally immature alpacas with severe carpal varus deformities.

Outcome analysis of 95 harness racehorses with confirmed dorsal displacement of the soft palate treated with laryngeal tie-forward surgery.

BACKGROUND: The laryngeal tie-forward (LTF) procedure is commonly used to treat intermittent dorsal displacement of the soft palate (iDDSP). There is a wide range in reported efficacy of treating horses with and without a definitive diagnosis of iDDSP. OBJECTIVES: To evaluate the racing performance of harness racehorses in which iDDSP had been definitely diagnosed and treated solely with the LTF procedure. STUDY DESIGN: Retrospective case series. METHODS: Ninety-five harness racehorses were treated with LTF for confirmed iDDSP. A definite diagnosis of iDDSP was made with high-speed treadmill or overground endoscopy. Upper respiratory tract (URT) disorders, short-term complications, and horses returning for recurrence of URT problems were recorded. Performance before and after LTF was assessed by reviewing career race records and comparing performance index (PI), and racing speed marks from the baseline, preoperative, and postoperative periods. The effect of basihyoid-cricoid (BC) net distance shortened on racing performance was assessed. RESULTS: Postoperatively, PI increased in 36/54 (67%, 95% CI 54%-79%) of experienced racehorses, and 44/67 (66%, 54%-77%) established or improved their racing speed mark relative to the preoperative period. As a group, PI decreased by a mean (SE) of 0.9 (0.17) points (P < .001) prior to diagnosis/surgery. Postoperatively, PI increased by 0.5 (0.16) points (P = .003), and racing speed improved by 0.83 (0.22) s (P < .001). Twenty-five percent (17%-34%) and 49% (39%-60%) of horses did not demonstrate a decline in PI and racing speed prior to diagnosis, respectively. Net BC distance shortening did not affect performance postoperatively. Twenty of 95 horses (21%, 13%-29%) had confirmed recurrence of iDDSP 46-708 days postoperatively. MAIN LIMITATIONS: Not all horses were evaluated with exercising endoscopy postoperatively. Racehorses inevitably develop other racing-related problems which confound studies of this nature. CONCLUSIONS: This study provides scientific support for the use of LTF to treat iDDSP in harness racehorses although iDDSP seems to affect harness racehorses differently as individuals.

Ultrasound-Guided Inferior Alveolar Nerve Block in the Horse: Assessment of the Extraoral Approach in Cadavers.

Blinded techniques to desensitize the inferior alveolar nerve (IAN) include intraoral, angled, and vertical extraoral approaches with reported success rates of 100%, 73%, and 59%, respectively. It has not been determined whether an ultrasound-guided extraoral approach is feasible. Further, the fascicular nature of the inferior alveolar and lingual nerves of the horse has not been described. The objectives of this study were to describe a low-volume ultrasound-guided vertical extraoral inferior alveolar nerve block technique and to describe the fascicular nature of these nerves. An ultrasound-guided approach to the IAN was conducted with a microconvex transducer and an 18-G, 15-cm spinal needle using a solution containing iodinated-contrast and methylene blue dye. Accuracy was assessed by contrast visualized at the mandibular foramen on computed tomography (CT) and methylene blue dye staining of the nerves on gross dissection. Sections of inferior alveolar and lingual nerves were submitted for histological analysis. Assessment by CT and dissection determined success rates of 81.3% and 68.8%, respectively; 68.8% of injections had inadvertent methylene blue dye staining of the lingual nerve. Nerve histology revealed both the inferior alveolar and lingual nerves to be multifascicular in nature. Mean fascicle counts for the inferior alveolar and lingual nerves were 29 and 30.8, respectively. The technique is challenging and no more accurate than previously published blinded techniques. Any extraoral approach to the IAN is likely to also desensitize the lingual nerve.

Assessing the Effect of Packing the Sulcus on Image Quality in Equine Digital Radiography.

The requirement to pack the sulcus of the equine foot as an aid to diagnostic interpretation before acquisition of dorsoproximal-palmarodistal oblique projections is debatable. The purpose of this study was to investigate the benefit of packing the sulcus in the assessment of normal anatomy. 23 cadaver limbs were radiographed in a podoblock (https://www.podoblock.com/products-page/podoblock/podoblock/) A non-packed image (NP) and a packed image (P) of the same foot were acquired. The image quality of P was graded against the reference NP by five observers, where -1=P was superior, 0=no difference between P and NP, and +1=NP was superior. Four anatomical criteria were used: the distal solar margin of the distal phalanx (DP), the vascular channels of DP, the palmar aspect of the distal interphalangeal joint and the articulation of the navicular bone with DP. A total Visual Grading Analysis Score of 0.28 indicates a preference for NP images. Packing was of benefit in only 10.8 per cent of cases. While judicious high-quality packing may be of benefit in a minority of cases, the routine packing of the sulcus in equine radiography was not found to be of benefit in the assessment of anatomical features in this study.

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 intra-articular 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 easily-learnt technique for an inexperienced veterinarian. Either approach may be employed in the field with a high level of accuracy, using widely available equipment.

Long-term maintenance of arytenoid cartilage abduction and stability during exercise after laryngoplasty in 33 horses.

OBJECTIVES: To (1) assess long-term maintenance of arytenoid cartilage abduction (ACA) after laryngoplasty (LP); and (2) correlate the residual grade of ACA and postoperative abductory loss with arytenoid cartilage stability (ACS) during exercise. STUDY DESIGN: Case series. ANIMALS: Horses re-examined after laryngoplasty (n = 33). METHODS: Of 89 LP horses (2005-2010), 33 had historic ACA data available and upper airway endoscopy at rest and during over-ground exercise (mean, 33 months; range, 4-71 months) after surgery. ACA grade at 1 and 6 weeks postoperatively were correlated to long-term ACA grade. Effects of long-term ACA grade and magnitude of postoperative abductory loss on ACS during exercise were investigated. RESULTS: Median ACA grade at 1 week (n = 33) was 2, reducing to grade 3 by week 6 (n = 16). Grade 3 abduction was maintained in the long-term. Correlation between ACA at 1 week and the long-term was poor (ρ = .43, P = .1), but there was good correlation between week 6 and long-term (ρ = .89, P < .001). Arytenoid cartilage instability was observed during exercise in 7/33 of horses, and not significantly associated with the ACA grade (P = .50), or the number of grades of ACA lost (P = .64). CONCLUSIONS: Limited abductory loss occurs after 6 weeks postoperatively. Resting ACA grade was not a useful predictor of ACS during exercise.