Potential regenerative rehabilitation technology: implications of mechanical stimuli to tissue health

Abstract

BackgroundMechanical loads induced through muscle contraction, vibration, or compressive forces are thought to modulate tissue plasticity. With the emergence of regenerative medicine, there is a need to understand the optimal mechanical environment (vibration, load, or muscle force) that promotes cellular health. To our knowledge no mechanical system has been proposed to deliver these isolated mechanical stimuli in human tissue. We present the design, performance, and utilization of a new technology that may be used to study localized mechanical stimuli on human tissues. A servo-controlled vibration and limb loading system were developed and integrated into a single instrument to deliver vibration, compression, or muscle contractile loads to a single limb (tibia) in humans. The accuracy, repeatability, transmissibility, and safety of the mechanical delivery system were evaluated on eight individuals with spinal cord injury (SCI).FindingsThe limb loading system was linear, repeatable, and accurate to less than 5, 1, and 1 percent of full scale, respectively, and transmissibility was excellent. The between session tests on individuals with spinal cord injury (SCI) showed high intra-class correlations (>0.9).ConclusionsAll tests supported that therapeutic loads can be delivered to a lower limb (tibia) in a safe, accurate, and measureable manner. Future collaborations between engineers and cellular physiologists will be important as research programs strive to determine the optimal mechanical environment for developing cells and tissues in humans.

Bone architecture adaptations after spinal cord injury: impact of long-term vibration of a constrained lower limb

“…We previously confirmed that the vibration intervention mimicked the mechanical input conditions of previous animal studies [19] and that it did not cause reflexive muscle contractions [30, 31]. We used a novel and sophisticated imaging approach to obtain outstanding imaging resolution for in vivo bone adaptations.…”

“…The trained leg was the dominant limb for three participants and the non-dominant limb for the other three individuals. The linearity, repeatability, accuracy, and transmissibility of vibration for this system have been previously described [19]. A compressive pre-load of 10–15%of body weight (%BW)was applied to the top of the knee to couple the limb segment to the vibrating surface, after which a cyclical load of 35 % of body weight was applied (5 s on and 10 s off) during the continuous vibration.…”

“…Therefore, we designed an experimental apparatus to administer a carefully controlled dose of vibration at a known compressive load in a way that more closely replicates the mechanical loading conditions of several successful animal studies [11, 13]. In this system, participants with SCI receive low-intensity vibration to a constrained lower limb segment from a seated position, rather than in standing through passive weight bearing [19], allowing the opposite limb to serve as a within-subject control.…”

Propagation of Acoustic Waves Caused by the Accelerations of Vibrating Hand-Held Tools in Viscoelastic Soft Tissues of Human Hands and a Mechanobiological Picture for the Related Injuries

“…As is well known (e.g., [1]), vibration and compressive loads are mechanical stimuli that have a powerful influence on living tissues. Recent studies in the E. Mamontov, V. Berbyuk Journal of Applied Mathematics and Physics animal models demonstrate that certain types of mechanical loads regulate various tissues.…”

“…7 -9 in [1] and the papers in [2]). One of the most well-known negative implications is hand-arm vibration syndrome (HAVS), or vibration-induced white finger (VWF).…”