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Strength and Cocontraction after Rhizotomy for Spastic Diplegia Cathleen Buckon, Susan Sienko Thomas, Gerald Harris, Joseph H. Piatt*, Michael Aiona, Michael Sussman Shriners Hospitals for Children, Portland, St. Christopher’s Hospital, Philadelphia *

What is strength? Functional weight-bearing walking Quantitative voluntary generation of force/torque

Hypotheses Rhizotomy does not affect quantitative measures of voluntary generation of force/torque in children with spastic diplegia. Rhizotomy does not affect agonist/antagonist cocontractions in children with spastic diplegia.

Subjects

Rhizotomy Technique Osteoplastic laminotomy L2 – L5 Dorsal rootlet dissection and stimulation L2 – S1 Monitoring of EMG activity and muscle contraction Rootlets cut average 42% Inpatient rehab 4 – 6 weeks Intensive outpatient rehab 6 months

Assessment Pre-op, 6 months, 1 year Isometric torque generation Elbow, knee, ankle Flex and extend Normalized for weight x height Surface EMG electrodes

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Normalized Strength (torque/height/weight)

Cocontraction

Conclusions Selective dorsal rhizotomy does not “unmask” weakness in spastic diplegic children. Spasticity and cocontraction seem to be distinct physiological phenomena. Selective dorsal rhizotomy does not suppress cocontraction in spastic diplegic children.