SPIRE spinous process stabilization plate: biomechanical evaluation of a novel technology. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2005.

Object: The authors studied the biomechanical properties of a novel spinous process stabilization plate (CD HORIZON SPIRE Spinal System) and present the results in comparison with those of other posterior fixation methods.
Methods: Ten functional cadaveric lumbar segments were subjected to nondestructive quasistatic loading forces in 10 different conditions: intact, destabilized (discectomy), fitted with spinous process plate (SPP) alone, with anterior-column support (ACS) alone, ACS with SPP, ACS with posterior translaminar facet screw (PTFS) fixation, ACS with unilateral pedicle screw and rod (UPSR) fixation, ACS with bilateral pedicle screw and rod (BPSR) fixation, UPSR alone, or BPSR alone. Stiffness and range of motion (ROM) data were compared using a repeated-measures, one-way analysis of variance. The construct with greatest mean limitation of flexion-extension ROM was ACS/SPP at 4.14 degrees whereas it was 5.75 degrees for ACS/UPSR fixation, 5.03 degrees for ACS/BPSR fixation, and 10.13 degrees for the intact spine. The SPIRE plate alone also provided greater flexion and extension stiffness, with less ROM than other posterior stabilization options. Fixation with BPSR with or without ACS resulted in the stiffest construct in lateral bending and axial rotation. The SPP and UPSR fixation groups were equivalent in resisting lateral bending and axial rotation forces with or without ACS.
Conclusions: The SPIRE plate effectively stabilized the spine, and the test results compare favorably with other fixation techniques that are more time consuming to perform and have greater inherent risks.