Comparison of segmental spinal instrumentation devices in the correction of scoliosis

Harrington distraction rods with either sublaminar wires or convexity compression rods and transverse loading wires were used to treat idiopathic scoliotic patients. Laboratory measurement of transverse forces and orthographic projection of the apical vertebra enabled calculation of x- and y- plane forces in addition to torque. The construct utilizing sublaminar wires generated more favorable corrective vectors. Both devices tended to further rotate the scoliotic spine. Use of the compression apparatus should be limited to spines where reduction of kyphosis is desirable.