Acute effects of aponeurotomy performed at multiple locations on muscular mechanics: assessment by finite element modeling

Abstract

The specific goal of the present study is to assess the effects of the number of interventions on the acute effects of aponeurotomy by using finite element modeling. EDL muscle of rat with extramuscular connections was modeled with aponeurotomies at three different locations (Location P,I and D); four conditions including single (Case P), two double (Case P-I and Case P-D) and triple (Case P-I-D) interventions were studied. Muscle length-force characteristics, sarcomere length distributions and muscle geometry of multiple aponeurotomy cases were compared to the ones of single aponeurotomized muscle. It was shown that the intended acute mechanical properties of aponeurotomy were enhanced mostly by triple interventions, but even these enhancements were fairly limited: (1) In triple aponeurotomized muscle, further force reduction was small (e.g. distal optimal forces for Case P and P-I-D are 68% and 64% of that of intact muscle). (2) The distal length range of active force exertion was increased by only 0.025% by two additive interventions, whereas single intervention (Case P) increased this length range by 44% of that of intact muscle. The proximal length range was even narrowed with additional interventions. (3) The sarcomere length distributions were not altered with multiple aponeurotomies. Our results indicate that the multiple interventions in the aponeurotomy should be questioned in terms of their limited enhancements in acute mechanical effects. Nevertheless, the geometrical changes might have clinical importance and this effect should be studied.|Keywords: Aponeurotomy, Muscle mechanics, Finite element modeling, Extramuscular myofascial force transmission, EDL.