TY - JOUR
T1 - Muscular dysfunction elicited by creep of lumbar viscoelastic tissue
AU - Solomonow, M.
AU - Baratta, R. V.
AU - Zhou, B. H.
AU - Burger, E.
AU - Zieske, A.
AU - Gedalia, A.
N1 - Funding Information:
This work was supported by the National Institute of Occupational Safety & Health with Grants R01-OH-04079 and R01-04-07622, and by The Occupational Medicine Research Center Grant HEF-(2000-05)-07 from The Louisiana Board of Regents. The senior author gratefully acknowledges the contributions of his graduate and medical students and orthopaedic residents: M. Stubbs, U. Gedalia, E. Eversull, S. Hatipkarasulu, L. Claude, M. Williams and M. Jackson. This review is based on the authors recent work which was published as original articles listed in the references as well as on-going research in the Occupational Medicine Research Center.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2003/8
Y1 - 2003/8
N2 - The biomechanics, histology and electromyography of the lumbar viscoelastic tissues and multifidus muscles of the in vivo feline were investigated during 20 min of static as well as cyclic flexion under load control and during 7 h of rest following the flexion. It was shown that the creep developed in the viscoelastic tissues during the 20 min of static or cyclic flexion did not fully recover over the 7 h of following rest. It was further seen that a neuromuscular disorder with five distinct components developed during and after the static and cyclic flexion. The neuromuscular disorder consisted of a decreasing magnitude of reflexive EMG from the multifidus upon flexion as well as of superimposed spasms. The recovery period was characterized by an initial muscle hyperexcitability, a slowly increasing reflexive EMG and a delayed hyperexcitability. Histological data from the supraspinous ligament demonstrate significant increase (× 10) in neutrophil density in the ligament 2 h into the recovery and even larger increase (×100) 6 h into the recovery from the 20 min flexion, indicating an acute soft tissue inflammation. It was concluded that sustained static or cyclic loading of lumbar viscoelastic tissues may cause micro-damage in the collagen structure, which in turn reflexively elicit spasms in the multifidus as well as hyperexcitability early in the recovery when the majority of the creep recovers. The micro-damage, however, results in the time dependent development of inflammation. In all cases, the spasms, initial and delayed hyperexcitabilities represent increased muscular forces applied across the intervertebral joints in an attempt to limit the range of motion and unload the viscoelastic tissues in order to prevent further damage and to promote healing. It is suggested that a significant insight is gained as to the development and implications of a common idiopathic low back disorder as well as to the development of cumulative trauma disorders.
AB - The biomechanics, histology and electromyography of the lumbar viscoelastic tissues and multifidus muscles of the in vivo feline were investigated during 20 min of static as well as cyclic flexion under load control and during 7 h of rest following the flexion. It was shown that the creep developed in the viscoelastic tissues during the 20 min of static or cyclic flexion did not fully recover over the 7 h of following rest. It was further seen that a neuromuscular disorder with five distinct components developed during and after the static and cyclic flexion. The neuromuscular disorder consisted of a decreasing magnitude of reflexive EMG from the multifidus upon flexion as well as of superimposed spasms. The recovery period was characterized by an initial muscle hyperexcitability, a slowly increasing reflexive EMG and a delayed hyperexcitability. Histological data from the supraspinous ligament demonstrate significant increase (× 10) in neutrophil density in the ligament 2 h into the recovery and even larger increase (×100) 6 h into the recovery from the 20 min flexion, indicating an acute soft tissue inflammation. It was concluded that sustained static or cyclic loading of lumbar viscoelastic tissues may cause micro-damage in the collagen structure, which in turn reflexively elicit spasms in the multifidus as well as hyperexcitability early in the recovery when the majority of the creep recovers. The micro-damage, however, results in the time dependent development of inflammation. In all cases, the spasms, initial and delayed hyperexcitabilities represent increased muscular forces applied across the intervertebral joints in an attempt to limit the range of motion and unload the viscoelastic tissues in order to prevent further damage and to promote healing. It is suggested that a significant insight is gained as to the development and implications of a common idiopathic low back disorder as well as to the development of cumulative trauma disorders.
UR - http://www.scopus.com/inward/record.url?scp=0038722150&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0038722150&partnerID=8YFLogxK
U2 - 10.1016/S1050-6411(03)00045-2
DO - 10.1016/S1050-6411(03)00045-2
M3 - Article
C2 - 12832168
AN - SCOPUS:0038722150
VL - 13
SP - 381
EP - 396
JO - Journal of Electromyography and Kinesiology
JF - Journal of Electromyography and Kinesiology
SN - 1050-6411
IS - 4
ER -