Search

Simple Summary: Spinal manipulation is recommended by clinical guidelines to treat low back pain. However, our understanding of how spinal manipulation alleviates pain and knowledge of the role that viscoelastic tissue properties play in the dampening of applied spinal manipulation forces in vivo is limited. Superficial and deep intramuscular pressures and applied forces were measured using miniature pressure catheters and a force transducer during low back spinal manipulation using a clinically available spinal manipulation device (Activator V) or a feedback motor in a deeply anesthetized animal model. Viscoelastic properties of muscle and other soft tissues greatly diminished applied spinal manipulative forces as well as intramuscular pressures in deep spinal tissues. These animal model findings may eventually have clinical implications or help to determine how spinal manipulation helps to alleviate muscular low back pain, particularly if it is determined that certain thresholds of deep tissue forces or intramuscular pressure changes are required to initiate a cascade of biological mechanisms resulting in a positive clinical treatment response. Current knowledge regarding biomechanical in vivo deep tissue measures related to spinal manipulation remain somewhat limited. More in vivo animal studies are needed to better understand the effects viscoelastic tissue properties (i.e., dampening) have on applied spinal manipulation forces. This new knowledge may eventually help to determine whether positive clinical outcomes are associated with particular force thresholds reaching superficial and/or deep spinal tissues. A computer-controlled feedback motor and a modified Activator V device with a dynamic load cell attached were used to deliver thrust spinal manipulations at various magnitudes to the L7 spinous process in deeply anesthetized animals. Miniature pressure catheters (Millar SPR-1000) were inserted unilaterally into superficial and deep multifidi muscles. Measurements of applied mechanical forces and superficial/deep multifidi intramuscular pressure changes were recorded during spinal manipulations delivered in vivo. Manipulative forces and net changes in intramuscular pressures reaching deep spinal tissues are greatly diminished by viscoelastic properties of in vivo tissues, which could have possible clinical safety and/or mechanistic implications. [ABSTRACT FROM AUTHOR]

2021, 10, 865 37 of 99 Hudson, Geoffrey Iacono, Pierluigi Huebner, Hanna Iacopi, Elisabetta Hueso, Miguel Iaculli, Flavia Hugelshofer, Michael Ianiro, Gianluca Hughes, Christopher V. Iannaccone, Andrea Hughes, David T. Iannuzzi, Clara Hughes, Jennifer Iasevoli, Felice Huh, Joo Young Iatí, Giuseppe Huhn, Ragnar Ibáñez-Costa, Alejandro Huling, Jennifer Ichibori, Yasuhiro Hull, Chris Ichida, Fukiko Hull, Louise Ichikawa, Hajime Hüls, Anke Ichikawa, Tetsuo Hulsebosch, Claire E. Ickmans, Kelly Hultcrantz, Rolf Idicula, Titto T Hultdin, Johan Idolazzi, Luca Hultin, Magnus Idrovo, Juan-Pablo Hultqvist, Jenny Ierardi, Enzo Humenberger, Michael Ifantides, Cristos Humpel, Christian Iga, Junichi Humrich, Jens Y. Iglesias-Osma, Maria Carmen Hung, Kenneth Iglseder, Bernhard Hung, Li-Fang Ignee, Andre Hunt, Beverley Jane Ignjatovic, Vera Hunt, William R. Igoe, Ann Hunter, Elizabeth G. Ihemelandu, Chukwuemeka Huotari, Matti Iijima, Kazutoshi Hupin, David Iijima, Takehiko Huppler, Anna R. Ijare, Omkar B. Hurford, William Ikada, Yoshito Hurtado-Fernández, Elena Ikeda, Keigo Hurtubise, Karen Ikeda, Youko Husby, Paul J. A. Ikeda, Yuki Huselstein, Céline Ikegaya, Naoki Hussain, Mulazim Ikezawa, Kenji Hussain, Rashad Ikuta, Toshikazu Hussain, Sultana Monira Ilatovskaya, Daria Husson, Olga Ildefonso, Cristhian J. Hutt, Axel Iliadi, Anna Huttner, Inken Iliescu, Cezar A. Hutton, George Joseph Iliou, Marie Christine Huynh-Do, Uyen Illek, Beate Hwang, Hun-Gyu Illuminati, Giulio Hwang, Hyeon Seok Ilves, Outi Hwang, Jae-Joon Imai, Chihaya Hwang, Ki-Chul Imai, Hisao Hwang, Mark Imai, Yoichi Hwang, Seung Rim Imamura, Masahiro Hwang, Yong Il Imamura, Teruhiko Hwu, Ruth S. Imamura, Yoshiki Hyatt, Hayden Imataki, Osamu Hyer, Steve Imbert, Véronique Hyink, Deborah Pinson Imbery, Terence A. Hynnekleiv, Torfinn Immins, Tikki Hytti, Maria Impellizzeri, Alessandra Iaccarino, Guido Impellizzeri, Pietro Iaccino, Enrico Inaki, Noriyuki J. Clin. [Extracted from the article]