Repair of pars interarticularis defect using a U-shaped rod–screw construct

Abstract

Study design Retrospective study. Aim To evaluate the efficacy of pars repair using pedicle screws connected with a U-shaped rod in the treatment of traumatic pars defect of the lower lumbar spine after failed conservative treatment. Materials and methods Eighteen patients with traumatic pars defect were managed from 2004 to 2009 by pars repair using two pedicle screws inserted into the involved vertebra and connected by a U-shaped rod passing under a spinous process and tightened after careful defect debridement and grafting. An MRI was performed to exclude adjacent disc degeneration. The patients were followed up using plain radiographs, in anteroposterior, lateral and oblique views. A computed tomography scan was performed to ensure pars healing. Results All patients had bilateral traumatic pars defect; their ages ranged from 16 to 27 years. Follow-up ranged from 24 to 53 months. Fourteen patients showed improved symptoms and returned to activity with full range of motion by the end of the sixth postoperative month. Two patients developed radicular pain; one showed complete improvement in the seventh week, whereas the other required revision. Two patients showed pseudoarthrosis and persistent pain that required revision with posterior lumbar interbody fusion. Conclusion This technique is an easy, effective technique of short operative duration with the advantage of nonviolation of the neural canal, no requirement for postoperative bracing and safe return to activity by the end of the sixth month, with no requirement for further fusion.