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Objective—To determine history; clinical, radiographic, ultrasonographic, and scintigraphic abnormalities; treatment; and outcome in horses with tuber coxae fractures and to describe a useful technique for obtaining a dorsomedial-ventrolateral 50° oblique radiographic view of the tuber coxa of the ilium in standing horses.
Design—Retrospective case series.
Animals—29 horses with fractures of tuber coxa.
Procedures—Data collected from medical records included signalment; history; horse use; severity and duration of lameness; radiographic, ultrasonographic, and scintigraphic findings; treatment; and outcome.
Results—All horses had a traumatic event leading to acute, unilateral hind limb lameness. Eighteen horses had a more severe lameness at the walk than at the trot; 22 of 29 horses had an abnormal gait with the hind limbs tracking to 1 side of the forelimbs. Twenty-four of 29 horses had palpable and visual asymmetry between the affected and unaffected tuber coxae. Twenty horses had radiography performed while sedated but standing, and fractures were reliably identified on the dorsomedial-ventrolateral 50° oblique radiographic views. Twenty-seven (27/29 [93%]) horses returned to athletic use. Horses sustaining partial fractures of the caudal aspect of tuber coxae returned to previous use significantly earlier (mean, 3 months), compared with horses with complete tuber coxae fractures (6.5 months).
Conclusions and Clinical Relevance—Horses with tuber coxae fractures returned to athletic soundness following extended periods of rest. Findings emphasized the need for obtaining a dorsomedial-ventrolateral 50° oblique radiographic view of the tuber coxa of the ilium in horses suspected of sustaining injury to this region.
To compare the speed of onset and analgesic effect of mepivacaine deposited within or immediately outside the neurovascular bundle at the base of the proximal sesamoid bones in horses.
6 horses with naturally occurring forefoot-related lameness.
In a crossover study design, horses were randomly assigned to receive 1 of 2 treatments first, with the second treatment administered 3 to 7 days later. Trotting gait was analyzed with an inertial sensor–based motion analysis system immediately before treatment to determine degree of lameness. Afterward, ultrasound guidance was used to inject 2% mepivacaine hydrochloride around the palmar digital nerves of the affected forelimb at the level of the base of the proximal sesamoid bones either within the subcircumneural space or outside the circumneural sheath. After injection, gait was reevaluated at 5-minute intervals for 45 minutes.
Mepivacaine deposition outside the circumneural sheath did not resolve lameness in any horse; for 3 horses, the mean time to 70% reduction of initial vertical head movement was 13.3 minutes, and the remaining 3 horses had no such reduction at any point. Mepivacaine deposition within the subcircumneural space resulted in a mean time to 70% reduction of initial vertical head movement of 6.7 minutes and mean time to resolution of lameness of 21.7 minutes.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that when peripheral nerves of horses lie within a sheath, local anesthetic solution should be deposited within the sheath for an effective nerve block. If local anesthetic solution is deposited outside the sheath, the nerve block may yield erroneous results.
Objective—To develop an endoscopic technique for use in monitoring devlopment of gastric ulcers via a gastric cannula during withholding of feed and administration of a finely ground diet to pigs.
Animals—6 pigs weighing between 60 and 70 kg.
Procedure—A gastric cannula was surgically inserted adjacent to the pars esophagea in each pig. Pigs were fed a finely ground diet for two 7-day periods that were separated by a 48-hour period during which feed was withheld. Endoscopic examination via the gastric cannula was used to monitor development of ulcers in the pars esophageal region of the pigs during the 48-hour period of feed withhold and subsequent 7-day feeding period. An ulcer score was assigned during each endoscopic examination. A final examination was performed during necropsy and compared with results for the final endoscopic examination.
Results—Consumption of a finely ground diet for 7 days resulted in progressive erosive damage to the pars esophageal region of the stomach. Further significant increases in ulcerative damage were detected after 24 and 48 hours of withholding of feed. Final examination during necropsy did not reveal significant differences from results obtained during the final endoscopic examination.
Conclusions and Clinical Relevance—Endoscopic examination via a gastric cannula was an effective means of monitoring ulcer development in the pars esophagea of pigs. Feeding a finely ground diet and withholding of feed induced endoscopically observable ulcers in the stratified squamous epithelial region of the stomach. Direct visual examination during necropsy confirmed the accuracy of endoscopic examination. (Am J Vet Res 2002;63:1076–1082)
To compare image quality and acquisition time of corneal and retinal spectral domain optical coherence tomography (SD-OCT) under 3 different sedation-anesthesia conditions in horses.
6 middle-aged geldings free of ocular disease.
1 randomly selected eye of each horse was evaluated via SD-OCT under the following 3 conditions: standing sedation without retrobulbar anesthetic block (RB), standing sedation with RB, and general anesthesia with RB. Five regions of interest were evaluated in the cornea (axial and 12, 3, 6, and 9 o’clock positions) and fundus (optic nerve head). Three diagnostic scans of predetermined quality were obtained per anatomical region. Image acquisition times and total scans per site were recorded. Corneal and retinal SD-OCT image quality was graded on a subjective scale from 0 (nondiagnostic) to 4 (excellent).
Mean values for the standing sedation without RB, standing sedation with RB, and general anesthesia conditions were 24, 23, and 17, respectively, for total cornea scan attempts; 23, 19, and 19 for total retina-scan attempts; 14.6, 13.2, and 9.2 minutes for total cornea scan time; 19.1, 9.2, and 13.0 for total retina scan time; 2.0, 2.3, and 2.5 for cornea grade; and 2.7, 2.9, and 2.5 for retina grade.
CONCLUSIONS AND CLINICAL RELEVANCE
The RB facilitated globe akinesia and improved the percentage of scans in frame and region of interest accuracy for retinal imaging via OCT in horses. Retrobulbar blocks improved clinical image acquisition while minimizing motion artifact.
To assess onset of analgesia for 3% chloroprocaine hydrochloride and 2% mepivacaine hydrochloride when used for median and ulnar nerve blocks in lame horses.
6 naturally lame horses.
A crossover experiment was conducted. Horses were assigned to 1 of 2 treatment groups (3% chloroprocaine or 2% mepivacaine first). Median and ulnar nerve blocks were performed in the lame limb with the assigned treatment. Lameness was objectively evaluated before treatment administration and at various points for 120 minutes after treatment with a wireless inertial sensor-based motion analysis system. Following a 7-day washout period, horses then received the other treatment and lameness evaluations were repeated.
Median and ulnar nerve blocks performed with 3% chloroprocaine resulted in more consistent, rapid, and profound amelioration of lameness than did blocks performed with 2% mepivacaine. Lameness decreased more between 20 and 40 minutes after injection when 3% chloroprocaine was used than when 2% mepivacaine was used. Complete resolution of lameness was detected a mean of 9 minutes after injection when median and ulnar nerve blocks were performed with 3% chloroprocaine and a mean of 28 minutes after injection when performed with 2% mepivacaine.
CONCLUSIONS AND CLINICAL RELEVANCE
3% chloroprocaine had a more rapid onset and provided better analgesia for median and ulnar nerve blocks in horses with naturally occurring lameness, compared with 2% mepivacaine. These favorable properties suggest that 3% chloroprocaine would be useful for performance of median and ulnar regional nerve blocks during complicated lameness evaluations.
Objective—To determine clinical and radiographic abnormalities in and outcome of horses with fractures of the greater tubercle of the humerus and to develop a radiographic technique for obtaining a cranioproximal-craniodistal oblique projection of the proximal portion of the humerus in standing horses.
Design—Retrospective case series.
Procedures—Data collected from medical records included signalment, history, horse use, severity and duration of lameness, radiographic and ultrasonographic findings, treatment, and outcome.
Results—All horses had a history of acute, unilateral lameness. Twelve of 15 had visual or palpable abnormalities in the shoulder region. In 6 of 8 horses, the fracture could be seen on a cranioproximal-craniodistal projection of the proximal portion of the humerus. In 2 horses, this was the only projection on which the fracture could be seen, and in an additional 2, this was the projection on which the fracture could be seen most reliably. Ten horses underwent surgery (fragment removal, 7; open reduction and internal fixation, 2; and exploration without fragment removal, 1), and 5 were treated with variable periods of stall rest and turnout. Eleven horses returned to athletic use, including 9 of the 10 treated surgically and 2 of the 5 treated without surgery.
Conclusions and Clinical Relevance—Results suggested that horses with fractures of the greater tubercle of the humerus can return to athletic soundness following treatment and emphasized the need for obtaining a cranioproximal-craniodistal radiographic projection of the proximal portion of the humerus in horses suspected to have an injury in this region.
Objective—To compare characteristics of horses recovering from 4 hours of desflurane anesthesia with and without immediate postanesthetic IV administration of propofol and xylazine.
Animals—8 healthy horses (mean ± SEM age, 6.6 ± 1.0 years; mean body weight, 551 ± 50 kg).
Procedures—Horses were anesthetized twice. Both times, anesthesia was induced with a combination of xylazine hydrochloride, diazepam, and ketamine hydrochloride and then maintained for 4 hours with desflurane in oxygen. Choice of postanesthetic treatment was randomly assigned via a crossover design such that each horse received an IV injection of propofol and xylazine or saline (0.9% NaCl) solution after the anesthetic episode. Recovery events were quantitatively and qualitatively assessed. Venous blood samples were obtained before and after anesthesia for determination of serum creatine kinase activity and plasma propofol concentration.
Results—Anesthetic induction and maintenance were unremarkable in all horses. Compared with administration of saline solution, postanesthetic administration of propofol and xylazine resulted in an increased interval to emergence from anesthesia but improved quality of recovery-related transition to standing. Compared with administration of saline solution, administration of propofol also delayed the rate of decrease of end-tidal concentrations of desflurane and carbon dioxide and added to conditions promoting hypoxemia and hypoventilation.
Conclusions and Clinical Relevance—Propofol and xylazine administered IV to horses after 4 hours of desflurane anesthesia improved the quality of transition from lateral recumbency to standing but added potential for harmful respiratory depression during the postanesthetic period.