Spinal growth modulation using a novel intravertebral epiphyseal device in an immature porcine model

Abstract

Fusionless growth modulation is an attractive alternative to conventional treatments of idiopathic scoliosis. To date, fusionless devices achieve unilateral growth modulation by compressing the intervertebral disc. This study explores a device to control spinal alignment and vertebral morphology via growth modulation while excluding the disc in a porcine model. A device that locally encloses the vertebral growth plate exclusive of the disc was introduced anteriorly over T5-T8 in four immature pigs (experimental) while three underwent surgery without instrumentation (sham) and two were selected as controls. Bi-weekly coronal and lateral radiographs were taken over the 12-week follow-up to document vertebral morphology and spinal alignment modifications via an inverse approach (creation of deformity). All animals completed the experiment with no postoperative complications. Control and sham groups showed no significant changes in spinal alignment. Experimental group achieved a final coronal Cobb angle of 6.5°±3.5° (constrained to the four instrumented levels) and no alteration to the sagittal profile was observed. Solely the experimental group ended with consistent vertebral wedging of 4.1°±3.6° amounting to a cumulative wedging of up to 25° and a concurring difference in left/right vertebral height of 1.24±1.86mm in the coronal plane. The proposed intravertebral epiphyseal device, for the early treatment of progressive idiopathic scoliosis, demonstrated its feasibility by manipulating spinal alignment through the realization of local growth modulation exclusive of the intervertebral disc.