title: The adaptive changes in muscle coordination following lumbar spinal fusion.
abstract: Limited back motion and damage of paraspinal muscles after spinal fusion surgery may lead to abnormal compensatory movements of the body. Whether neuromuscular control changes after surgery remains unclear. The purpose of the study was to identify the muscle activation patterns employed before and after lumbar spinal fusion. Nineteen patients having low back pain and undergoing minimally invasive lumbar spinal fusion were evaluated at 1 day before and 1 month after fusion surgery. Nineteen matched healthy participants were recruited as controls. Patients' pain severity and daily activity functioning were recorded. All participants were instructed to perform forward reaching, and the muscle activities were monitored using surface electromyography (EMG) with sensors placed on both sides of their trunk and lower limbs. The muscle activation patterns were identified using the principal component analysis (PCA). All patients had significant improvements in pain intensity and daily activity functioning after surgery, but exhibited an adaptive muscle activation pattern during forward reaching movement compared with the controls. Significant loading coefficients in the dominant movement pattern (reflected in the first principal component) were observed in back muscles for controls whereas in leg muscles for patients, both pre- and postoperatively. Despite substantial improvements in pain intensity and daily activity functioning after surgery, the patients exhibited decreased paraspinal muscle activities and adaptive muscle coordination patterns during forward reaching. They appeared to rely mainly on their leg muscles to compensate for their insufficient paraspinal muscle function. Early intervention focusing on training paraspinal muscles should be considered after spinal fusion surgery.
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Ting-Yun
authors.initials: TY
authors.lastname: Wang
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan; Division of Minimally Invasive Spine Surgery & Orthopedic Surgery, Department of Surgery, Far Eastern Memorial Hospital, New Taipei, Taiwan.
authors.forename: Jwo-Luen
authors.initials: JL
authors.lastname: Pao
authors.affiliation: Department of Orthopedics, National Taiwan University & Hospital, Taipei, Taiwan.
authors.forename: Rong-Sen
authors.initials: RS
authors.lastname: Yang
authors.affiliation: Department of Computer Science & Information Engineering, National Taiwan University, Taiwan.
authors.forename: Jyh-Shing Roger
authors.initials: JS
authors.lastname: Jang
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan; Physical Therapy Center, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: wlhsu@ntu.edu.tw.
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Hsu
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D001415:Back; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010147:Pain Measurement; D025341:Principal Component Analysis; D016059:Range of Motion, Articular / Q000502:physiology; D013123:Spinal Fusion
keywords: Electromyography (EMG); Low back pain (LBP); Motor control; Reaching