The Influences of Different Insertion Conditions of Coflex Interlaminar Dynamic Stabilization on the Lumbar Spine Sagittal Alignment: A Perspective Clinical Study

Abstract

Introduction Selective decompression with interspinous distractive device insertion is one of the surgical options for the treatment of degenerative lumbar spine stenosis. Concerns of loss of lordosis and change of the sagittal alignment of the lumbar spine after interspinous distractive device insertion have been raised. To evaluate the influence of interspinous distractive device insertion on the sagittal alignment of the lumbar spine, a perspective clinical study was conducted. Materials and Methods From 2008 to 2010, 59 consecutive patients with single level degenerative lumbar stenosis at L45 were treated with selective decompression and Coflex interlaminar dynamic stabilization. There were 21 male and 38 female with an average age of 62.4 years (52-73). After decompression, Coflex device was inserted randomly under nonload condition (no distraction between spinous processes, NL group) and preload condition (3-5 mm distraction between spinous processes, PL group). Radiographic evaluation of the change of sagittal angle of the index level (IA), sagittal lordosis of the lumbar spine (LL), and the range of motion of the lumbar spine (ROM) were using standing lateral and flexion-extension lateral X-rays, pre- and postoperatively and 6 months postoperatively. Statistical analysis was conducted and t-test comparison was evaluated utilizing SPSS 16 computer software. Results All patients underwent surgery safely and no major intraoperative complications such as neurological injury, dural tear, spinous fracture, and infection were occurred. The change of sagittal alignment of index segment and lumbar spine, as well as the ROM of the lumbar spine, is shown in Table 1. The sagittal lordosis at the index segment and lumbar spine was decreased in the PL group comparing with the NL group ( p < 0.05), but there was no significant change of the ROM of the lumbar spine in both groups. Conclusion Although Coflex inter-laminar insertion under pre-load condition decreased the sagittal lordosis of the index segment and the lumbar spine, the range of motion of the lumbar spine was maintained. Large patients and longer follow-up evaluation is warranted to evaluate the influence of the sagittal alignment as well as the relationship with the clinical outcome. Disclosure of Interest None declared