Background: Acoustic emission from structures subject to external loads can be monitored to detect internal damage before destruction occurs. It is hypothesised that deformation of soft tissue will emit acoustic signals which may aid early detection of deep tissue injury, particularly in the lower limb amputee population. No previous studies have applied this method to biological soft tissue.
Objective: To determine if skeletal muscle tissue produced measurable acoustic emission during dynamic tensile loading with the aim to establish a reliable biomarker for lower limb prosthetic socket fit quantification and prosthetic health.
Study Design: Experimental study design.
Methodology: In this research article, Sus scrofa domesticus (pork) muscle and Gallus gallus domesticus (chicken) muscle specimens (10mm width x 45mm height x 4mm depth) were submerged into saline baths while an Instron testing machine applied displacement controlled tensile loads. Time stamped, load, displacement and acoustic signal (hydrophone) data was collected.
Findings: The pork muscle was tested to failure being subject to tensile load. Prior to failure, no peaks were found in the amplitude or frequency of the acoustic signal to indicate that either tissue deformation or failure was occurring. Data gathered during chicken muscle testing was inconclusive.
Conclusions: Results displayed that tensile testing of pork intercostal muscle produced tissue deformation and failure with no detectable change in the amplitude or frequency of the background sound during tensile loading. The other specimens failed before reaching the same levels of tensile load. Further studies are required in order to address the numerous limitations of this study.
Layman's abstract : Humans are made of biological material, some are hard such as the skeleton and some are soft as in muscles. When the soft tissue are under a too high stress condition, such as in diabetic patients, we talk about deep tissue injury. It has been proven that deep tissue injury negatively impacts the affected persons’ quality of life, through a reduction in mobility and ability levels. Deep tissue injury is additionally very costly to health care systems worldwide. Unfortunately, those with lower limb dysvascularity (in particular, amputees with limb loss secondary to dysvascularity and/or neuropathy) are at heightened risk of further damage from deep tissue injury. Therefore, this study ultimately aims to be used as a basis in order to determine if, at some stage, it would be possible to detect tissue that was ‘at risk’ of developing deep tissue injury.