title: Voluntary activation of biceps-to-triceps and deltoid-to-triceps transfers in quadriplegia.
abstract: The biceps or the posterior deltoid can be transferred to improve elbow extension function for many individuals with C5 or C6 quadriplegia. Maximum strength after elbow reconstruction is variable; the patient's ability to voluntarily activate the transferred muscle to extend the elbow may contribute to the variability. We compared voluntary activation during maximum isometric elbow extension following biceps transfer (n = 5) and deltoid transfer (n = 6) in three functional postures. Voluntary activation was computed as the elbow extension moment generated during maximum voluntary effort divided by the moment generated with full activation, which was estimated via electrical stimulation. Voluntary activation was on average 96% after biceps transfer and not affected by posture. Individuals with deltoid transfer demonstrated deficits in voluntary activation, which differed by posture (80% in horizontal plane, 69% in overhead reach, and 70% in weight-relief), suggesting inadequate motor re-education after deltoid transfer. Overall, individuals with a biceps transfer better activated their transferred muscle than those with a deltoid transfer. This difference in neural control augmented the greater force-generating capacity of the biceps leading to increased elbow extension strength after biceps transfer (average 9.37 N-m across postures) relative to deltoid transfer (average 2.76 N-m across postures) in our study cohort.
authors.affiliation: Edward Hines, Jr. VA Hospital, Hines, IL, United States of America.|Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America.|Department of Physical Medicine & Rehabilitation Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America.
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Peterson
authors.affiliation: Edward Hines, Jr. VA Hospital, Hines, IL, United States of America.|Department of Orthopaedic Surgery and Rehabilitation, Stritch School of Medicine, Loyola University Maywood, IL, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bednar
authors.affiliation: The Cleveland FES Center at MetroHealth, Cleveland, OH, United States of America.|Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Bryden
authors.affiliation: The Cleveland FES Center at MetroHealth, Cleveland, OH, United States of America.|Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America.|Department of Orthopaedics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Keith
authors.affiliation: Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America.|Department of Physical Medicine & Rehabilitation Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America.|Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States of America.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Perreault
authors.affiliation: Edward Hines, Jr. VA Hospital, Hines, IL, United States of America.|Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America.|Department of Physical Medicine & Rehabilitation Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America.|Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States of America.
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Murray
mesh_terms: D000293:Adolescent; D000328:Adult; D001132:Arm; D057645:Deltoid Muscle; D004551:Elbow Joint / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011782:Quadriplegia / Q000503:physiopathology / Q000601:surgery*; D016059:Range of Motion, Articular; D013709:Tendon Transfer / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult