The in vivo biodynamic properties of the intact equine linea alba.

The research focuses on the study of the biophysical properties of a horse’s abdominal muscle, known as the linea alba, using liquid metal strain gauges. The aim is to understand its function during physical activity and anaesthesia, and to shed light on post-operative care measures to prevent wound dehiscence.

Methodology

• The scientists surgically implanted Liquid Metal Strain Gauges (LMSG) at three different locations on the Linea Alba (LA) of eight horses. LA is the middle tendon-like part of the muscular wall of the abdomen in vertebrates, and especially prominent in horses.
• The team recorded the strain, strain rate, change in strain, and stress on the LA during different activities such as standing, vocalising, walking, trotting, cantering, as well as during general anaesthesia and recovery from it. Even activities like rectal palpation which veterinarians undertake to examine the horse’s health were considered.
• They also attempted to quantify the stress on the LA using an in vitro tensiometric technique.
• The scientists further evaluated whether an abdominal bandage had any effect on strain magnitude.

Results

• The results showed that the stress-strain responses differed significantly with the location on the LA, but all resulted in a typical relationship for viscoelastic tissues (those that exhibit both viscous and elastic characteristics).
• The maximum peak stress, peak strain, and change in strain were observed during the horse’s recovery from anaesthesia. The highest strain rate was recorded during a horse’s canter (a controlled three-beat gait).
• The abdominal bandage did not provide any consistent change in strain magnitude.
• The researchers found that the lower part of the LA, called the ‘caudal LA’, experienced greater stress and strain than the upper, or ‘cranial’, portion of the LA.
• They also recorded the strain variation with the cadence (rhythm of the horse’s strides).

Conclusion

• The researchers concluded that the LMSGs were suitable for recording LA biodynamics and found that this band of tissue isn’t uniformly rigid or flexible throughout its length.
• They suggested that the LA is designed to withstand acceleration and deceleration forces associated with strenuous activity which might otherwise harm the abdominal viscera or internal organs.
• They also found that the strain on the LA varied significantly with the phase of stride.
• From the results, it was inferred that post-operative care involving minimal exercise and careful rectal palpation could reduce the likelihood of incisional dehiscence (wound splitting open).
• The data collected in this research will provide a basis for more accurate models for future laboratory studies.