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Abstract

Objective—To determine whether high plasma fibrinogen concentration (≥ 900 mg/dL) is a valid indicator of physeal or epiphyseal osteomyelitis in foals.

Design—Retrospective case series.

Animals—17 foals with physeal or epiphyseal osteomyelitis with or without septic arthritis, 17 foals with septic arthritis alone, 20 foals with non–Rhodococcus equi pneumonia, and 22 healthy foals.

Procedures—Medical records were reviewed for information regarding signalment and total WBC count, segmented neutrophil count, and plasma fibrinogen concentration measured when foals were initially evaluated at the hospital. Whether the foals survived to discharge from the hospital was also determined.

Results—Foals with physeal or epiphyseal osteomyelitis had higher plasma fibrinogen concentrations than did foals in the other 3 groups. Sixteen of 17 affected foals had values ≥ 900 mg/dL. The positive predictive and negative predictive values for plasma fibrinogen concentrations between 900 and 1,500 mg/dL as an indicator of osteomyelitis were 84.2% and 98.2%, respectively. Fibrinogen concentrations of 200 to 400 mg/dL and 500 to 800 mg/dL were associated with foals not having physeal osteomyelitis. Having septic arthritis alone or non–R equi pneumonia was significantly associated with a plasma fibrinogen concentration between 500 and 800 mg/dL; however, the positive predictive value of this range as an indicator of those diseases was low. Foals with osteomyelitis had greater total WBC and segmented neutrophil counts than did foals with septic arthritis alone.

Conclusions and Clinical Relevance—A plasma fibrinogen concentration of ≥ 900 mg/dL may be useful as an indicator of physeal or epiphyseal osteomyelitis in foals.

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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare the effects of 2 approaches and 2 injection volumes on diffusion of mepivacaine hydrochloride for local analgesia of the deep branch of the lateral plantar nerve (DBLPN) in horses.

Design—Experimental study.

Animals—16 adult horses.

Procedures—Either 2 mL (low volume) or 8 mL (high volume) of mepivacaine hydrochloride-iohexol (50:50 mixture) was injected by means of 1 of 2 techniques to produce analgesia of the DBLPN. For technique 1, the needle was inserted 15 mm distal to the head of the fourth metatarsal bone and directed perpendicular to the limb. For technique 2, the needle was inserted 20 mm distal to the head of the fourth metatarsal bone and was directed in a proximodorsal direction. Lateromedial radiographs were obtained before and 5, 15, 30, and 60 minutes after injection. Radiographs were evaluated to determine the proximal and distal extent of diffusion of the contrast solution and presumably anesthetic agent and whether contrast agent appeared to be present in the tarsal sheath or tarsometatarsal joint.

Results—A high degree of variability in contrast solution diffusion was noted among injections. High-volume injections diffused significantly further proximally and distally than did low-volume injections. Contrast agent was documented within the tarsal sheath in 5 of 32 (16%) injections and within the tarsometatarsal joint in 2 of 32 (6%) injections. No significant difference was found for risk of inadvertent tarsal sheath or tarsometatarsal joint injection between the 2 techniques or the 2 volumes of anesthetic used. Mepivacaine diffused significantly further distally with technique 1 than with technique 2 but diffused significantly further proximally with technique 2 than with technique 1. For both techniques, diffusion in the distal but not the proximal direction significantly increased over time.

Conclusions and Clinical Relevance—Results indicated that the proximal and distal diffusion of the mepivacaine-iohexol solution was quite variable following either DBLPN nerve block technique.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To investigate tissue diffusion of anesthetic agent following administration of low palmar nerve blocks (LPBs) in horses.

Design—Randomized clinical trial.

Animals—12 adult horses.

Procedures—In 9 horses, mepivacaine hydrochloride–iohexol (50:50 dilution) injections were administered bilaterally (2 or 4 mL/site) to affect the medial and lateral palmar and palmar metacarpal nerves (4 sites). Lateral radiographic views of both metacarpal regions were obtained before and at 5, 15, 30, 60, 90, and 120 minutes after block administration; proximal and distal extents of contrast medium (and presumably anesthetic agent) diffusion from palmar and palmar metacarpal injection sites were measured and summed to determine total diffusion. Methylene blue solution was injected in forelimbs of 3 other horses that were subsequently euthanized to determine the potential route of anesthetic agent diffusion to the proximal suspensory ligament region.

Results—Mean extents of proximal and total contrast medium diffusion were 4.0 and 6.6 cm, respectively, for the palmar metacarpal nerves and 4.3 and 7.1 cm, respectively, for the palmar nerves. Subtle proximal diffusion secondary to lymphatic drainage was evident in 17 of the 18 limbs. Contrast medium was detected in the metacarpophalangeal joint or within the digital flexor tendon sheath in 8 and 7 limbs, respectively. In the cadaver limbs, methylene blue solution did not extend to the proximal suspensory ligament region.

Conclusions and Clinical Relevance—In horses, LPBs resulted in minimal proximal diffusion of anesthetic agent from the injection sites. Limbs should be aseptically prepared prior to LPB administration because inadvertent intrasynovial injection may occur.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the clinical applications, short and long-term survival, and complications of using transfixation pin casts for treatment of comminuted phalangeal fractures in adult horses.

Design—Retrospective case series.

Animals—20 horses.

Procedures—Medical records were reviewed to obtain information regarding signalment, fracture location, treatment methods, complications, and short-term survival (discharge from hospital). Long-term follow-up information was obtained via contact with owners or trainers.

Results—12 fractures were in a hind limb, and 8 were in a forelimb. Fourteen fractures occurred in a middle phalanx, and 6 occurred in a proximal phalanx. Eleven fractures were treated with internal fixation combined with transfixation pin casts, and 9 fractures were treated with transfixation pin casts alone. Transfixation pin casts were maintained for a mean of 52 days (median, 49 days; range, 1 to 131 days). Fourteen (70%) horses were discharged from the hospital, whereas 6 (30%) were euthanized during the treatment period. Reasons for euthanasia included secondary fracture of the third metacarpal or metatarsal bone, avascularity of the distal aspect of the limb associated with an open fracture, and displacement of the fracture after transfixation pin cast removal. A significantly greater number of horses was discharged from the hospital when the transfixation pin cast was maintained for > 40 days, compared with those in which the transfixation pin cast was maintained for < 40 days.

Conclusions and Clinical Relevance—Results suggested that horses should be maintained in a transfixation pin cast for a minimum of 40 days, as this was associated with an increase in short-term survival without an increased risk of catastrophic failure.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the long-term clinical outcome of horses with distal tarsal osteoarthritis (OA) in which a 3-drill-tract technique was used to induce arthrodesis of the affected joints, identify any preoperative or operative factors associated with outcome, and describe any complications associated with the technique.

Design—Retrospective study.

Animals—54 horses.

Procedure—Medical records were reviewed for information on signalment, use, history, physical and lameness examination findings, surgical technique, and postoperative care. Radiographs were examined, and severity of OA was graded. Follow-up information was obtained through telephone interviews with owners at least 13 months after the procedure.

Results—32 (59%) horses had a successful outcome, 6 (11%) improved but were not sound after surgery, and 16 (30%) did not improve following surgery. Outcome was negatively associated with the previous use of intra-articular injections. Few postoperative complications were evident.

Conclusions and Clinical Relevance—Results suggest that distal tarsal OA in horses can be successfully treated by means of distal tarsal arthrodesis with a 3-drill-tract technique. Horses with advanced distal tarsal OA are likely to have poorer outcomes, and the procedure will likely be of minimal benefit in horses with concomitant causes of hind limb lameness prior to surgery and in horses with preexisting proximal intertarsal joint disease. (J Am Vet Med Assoc 2003; 223;1800–1805)

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in Journal of the American Veterinary Medical Association