Bone Biopsy in the Horse: 1. Method Using the Wing of Ilium

Abstract

Summary Two hundred and five bone biopsies from the wing of ilium were taken from 52 growing and 70 older horses. The method was initially evaluated in 4 horses at post mortem and then performed in 26 horses under general anaesthesia. The technique was later developed for biopsying horses in the standing position under local anaesthesia (n = 70 adults; n = 22 foals). The core of the bone biopsy consisted of a central cancellous portion between two cortices. This type of sample allowed a complete histomorphometrical analysis. An integral part of the procedure was intravital bone labelling using fluorochromes with a known interval between labels. Potential hazards associated with the use of Oxytetracycline labels included the onset of diarrhoea and laminitis in some foals. The method was simple, safe and efficient for both anaesthetised and standing horses. The only difficulties encountered were minor and were associated with blunting of the drill bit, scoring of the internal surface of the drill bit guide and occasional loss of the distal part of the biopsy core. Post operative complications included haematoma formation and skin infections. It was concluded that this technique offered a quick and effective method of collecting bone biopsies in horses, which facilitated the quantitative assessment of skeletal changes.

Histomorphometric assessment of bone biopsies from foals fed diets high in phosphorus and digestible energy

“…Bone biopsies were analysed by histomorphometry from contralateral sites of the wing of ilium in foals fed diets that resulted in lesions of DCP. Inter-bone (right ~v left) histomorphometric data do not vary significantly as demonstrated from biopsies taken from contralateral sides of equine (Savage et al 1991a) and human ilium . Removal of consecutive biovsies from the contralateral side in the longitudinal study here is acceptable, although the systemic acceleratorv heno omen on mav have a confounding effect on bone .…”

“…Towards the end of the exaeriment in Weeks 15 and 16. fluorescein com~lexone (2.4-his [<N-di(carbomethyl)aminomet'hyl] fluorescein: BDH ~hemicals, Australia', was administered at a dose of 10 mdkg. Fluorescein complexdne was dissolved in 40-60 ml 3% rw/v) sodium hydroxide and infused in 500 ml0.9% NaCl (Savage et al 1991a).…”

Bone-Labeling Techniques

“…For example, tetracyclines should be used with caution in horses because of the risk of life-threatening diarrhea. 52 In the author's experience, a single dose of demeclocycline can be hepatotoxic in rats at doses higher than 20 mg/kg. Demeclocycline should not be used in amphibians.…”

“…In an experiment with toads, tetracycline at a dose of 100 mg/kg showed no signs of toxicity, but all animals died within a few weeks after a subcutaneous (sc) injection of 20 mg/kg demeclocycline. 6 With the exception of horses (10-15 mg/kg), 52,53 tetracycline and oxytetracycline can be given at the dose of 20-25 mg/kg to all animals. Demeclocycline is usually administered at a dose of 20 mg/kg.…”

Sternal Bone Biopsy in Standing Horses

“…To obtain an adequate bone sample for histomorphometric analysis, bone biopsy—an invasive technique—is necessary. Ilium and rib bone biopsy sites have been described for horses 8,9 and custom‐made, powered bone biopsy instruments have been used 6,9 . Fracture of the cancellous bone architecture of some specimens was reported in both studies.…”