The in vivo biodynamic properties of the intact equine linea alba



Liquid metal strain gauges (LMSG) were implanted surgically at three locations on the intact linea alba (LA) in eight horses. LA strain, strain rate, change in strain and stress were recorded during general anaesthesia, recovery from anaesthesia, standing, vocalisation, rectal palpation and at the walk, trot and canter. LA stress was quantitated using an in vitro tensiometric technique. Stress-strain responses differed significantly (P<0.05) with location, but each described a characteristic relationship for viscoelastic tissues. Maximum peak stress, peak strain and change in strain occurred during anaesthetic recovery. Maximum strain rate occurred at the canter. An abdominal bandage provided no consistent change in strain magnitude. The caudal LA experienced greater stress and strain than the cranial LA. LA strain varied cyclically with cadence. It was concluded that: LMSGs provide a suitable technique for recording LA biodynamics; the dynamic properties of the LA are not homogenous throughout its length; the LA is suited to accommodate the rapid acceleration/deceleration forces associated with strenuous activity which might otherwise cause injury to abdominal viscera; and LA resultant strain alters significantly with phase of stride. It was implied that the likelihood of incisional dehiscence is reduced by minimising exercise and rectal palpation post operatively. The data will permit a more accurate representation of physiological conditions for future laboratory studies.