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Deep Digital Flexor Tenotomy as a Treatment for Horses With Chronic Laminitis
Abstracts Vol 30, No 2 (2010)
111
a small group of animals. All control and laminitis-prone ponies had post dexamethasone insulin concentrations of < or >75 mIU/L, respectively. This has not been applied to the wider population.
Deep Digital Flexor Tenotomy as a Treatment for Horses With Chronic Laminitis
MATERIALS & METHODS
C.F. Mitchell and R.E. Beadle, Equine Health Studies Program, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
DSTs were performed in 41 mixed breed previously laminitic (although not laminitic at the time of testing) ponies. Dexamethasone (0.04mg/kg) was injected between 4-5pm after obtaining a basal blood sample. A second blood sample was obtained 19 hours later. Serum cortisol and insulin analysis was by chemiluminescent assays at two commercial laboratories (Liphook Equine Hospital and Beaufort Cottage Laboratory, UK).
TAKE HOME MESSAGE In horses with severe deviation of P3 and/or solar penetration, pasture soundness is potentially obtainable.
INTRODUCTION RESULTS All animals had post dexamethasone cortisol concentrations < 30 mmol/l (mean SD; 20.0 10.1 mmol/l). Basal insulin concentration ranged from 1 to 335 mIU/L (65.4 89.9 mIU/L) and was above the reference range (>40 mIU/L) in 18/41 animals. Post dexamethasone insulin concentration ranged from 7.6 to 2790.0 mIU/L (268.4 472.1 mIU/L) and was >75 mIU/L in 25/41 (61%) animals. Basal insulin >40 mIU/L or post dexamethasone insulin >75 mIU/L was evident in 28/41 (68%) animals. If the results were divided according to the time of year the test was performed, post dexamethasone insulin >75 mIU/L was evident in 9/12 (75%) animals in summer (June - August), 10/22 (45%) in autumn (Sept - Nov) and 6/7 (85%) in winter (Dec - Feb). The results in autumn were significantly (p < 0.05) different from those in summer and winter.
DISCUSSION Whilst post dexamethasone insulin concentrations of >75 mIU/L previously had a sensitivity and specificity of 100%, when applied to a large pony population, the sensitivity was 61%. However, the insulin sensitivity of the animals in the present study was not evaluated and it is possible that within this larger population there are animals in which the predisposition to laminitis is not associated with IR. The sensitivity changed according to the time of year the test was performed, being greatest in winter and least in autumn.
CONCLUSION, CLINICAL RELEVANCE & TAKE HOME MESSAGE Insulin response to a DST may be useful in the study of large populations of animals, but less so for the identification of an individual laminitis prone animal.
Laminitis with severe deviation of P3 often requires more than therapeutic shoeing alone to regain soundness. DDF tenotomy can be performed to decrease tension on the dorsal laminae, to increase comfort and to facilitate more appropriate corrective trimming and shoeing.
MATERIALS AND METHODS Seven horses were treated using this technique. A complete history was obtained and physical examination performed at the initial presentation and each time a horse was re-examined, at 6 week intervals. Endocrine testing was performed as deemed appropriate. DP and LM radiographs were obtained with a metallic marker placed into the dorsal hoof wall each time radiographs were taken. The decision to perform a DDF tenotomy was made on the basis of the results of the physical exam and radiographic findings. The goals of therapeutic shoeing were to pull the breakover back to beneath the tip of P3, to float the hoof wall at the toe and to provide appropriate frog and heel support.
RESULTS 3/7 horses had solar penetration, secondary to P3 deviation, prior to performing a DDF tenotomy. One year after presentation, 7/7 horses were pasture sound and 6/7 weren’t receiving any analgesics. 3/7 horses required continual treatment with pergolide for Cushing’s disease.
DISCUSSION/CONCLUSION/CLINICAL RELEVANCE The therapeutic regime described herein resulted in a high level of client satisfaction and patient comfort. DDF tenotomy can be a useful surgery and should be considered, where appropriate, as a complimentary therapy to therapeutic shoeing in horses with chronic laminitis.
111
a small group of animals. All control and laminitis-prone ponies had post dexamethasone insulin concentrations of < or >75 mIU/L, respectively. This has not been applied to the wider population.
Deep Digital Flexor Tenotomy as a Treatment for Horses With Chronic Laminitis
MATERIALS & METHODS
C.F. Mitchell and R.E. Beadle, Equine Health Studies Program, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
DSTs were performed in 41 mixed breed previously laminitic (although not laminitic at the time of testing) ponies. Dexamethasone (0.04mg/kg) was injected between 4-5pm after obtaining a basal blood sample. A second blood sample was obtained 19 hours later. Serum cortisol and insulin analysis was by chemiluminescent assays at two commercial laboratories (Liphook Equine Hospital and Beaufort Cottage Laboratory, UK).
TAKE HOME MESSAGE In horses with severe deviation of P3 and/or solar penetration, pasture soundness is potentially obtainable.
INTRODUCTION RESULTS All animals had post dexamethasone cortisol concentrations < 30 mmol/l (mean SD; 20.0 10.1 mmol/l). Basal insulin concentration ranged from 1 to 335 mIU/L (65.4 89.9 mIU/L) and was above the reference range (>40 mIU/L) in 18/41 animals. Post dexamethasone insulin concentration ranged from 7.6 to 2790.0 mIU/L (268.4 472.1 mIU/L) and was >75 mIU/L in 25/41 (61%) animals. Basal insulin >40 mIU/L or post dexamethasone insulin >75 mIU/L was evident in 28/41 (68%) animals. If the results were divided according to the time of year the test was performed, post dexamethasone insulin >75 mIU/L was evident in 9/12 (75%) animals in summer (June - August), 10/22 (45%) in autumn (Sept - Nov) and 6/7 (85%) in winter (Dec - Feb). The results in autumn were significantly (p < 0.05) different from those in summer and winter.
DISCUSSION Whilst post dexamethasone insulin concentrations of >75 mIU/L previously had a sensitivity and specificity of 100%, when applied to a large pony population, the sensitivity was 61%. However, the insulin sensitivity of the animals in the present study was not evaluated and it is possible that within this larger population there are animals in which the predisposition to laminitis is not associated with IR. The sensitivity changed according to the time of year the test was performed, being greatest in winter and least in autumn.
CONCLUSION, CLINICAL RELEVANCE & TAKE HOME MESSAGE Insulin response to a DST may be useful in the study of large populations of animals, but less so for the identification of an individual laminitis prone animal.
Laminitis with severe deviation of P3 often requires more than therapeutic shoeing alone to regain soundness. DDF tenotomy can be performed to decrease tension on the dorsal laminae, to increase comfort and to facilitate more appropriate corrective trimming and shoeing.
MATERIALS AND METHODS Seven horses were treated using this technique. A complete history was obtained and physical examination performed at the initial presentation and each time a horse was re-examined, at 6 week intervals. Endocrine testing was performed as deemed appropriate. DP and LM radiographs were obtained with a metallic marker placed into the dorsal hoof wall each time radiographs were taken. The decision to perform a DDF tenotomy was made on the basis of the results of the physical exam and radiographic findings. The goals of therapeutic shoeing were to pull the breakover back to beneath the tip of P3, to float the hoof wall at the toe and to provide appropriate frog and heel support.
RESULTS 3/7 horses had solar penetration, secondary to P3 deviation, prior to performing a DDF tenotomy. One year after presentation, 7/7 horses were pasture sound and 6/7 weren’t receiving any analgesics. 3/7 horses required continual treatment with pergolide for Cushing’s disease.
DISCUSSION/CONCLUSION/CLINICAL RELEVANCE The therapeutic regime described herein resulted in a high level of client satisfaction and patient comfort. DDF tenotomy can be a useful surgery and should be considered, where appropriate, as a complimentary therapy to therapeutic shoeing in horses with chronic laminitis.