Excision of the Posterior Longitudinal Ligament During Anterior Cervical Corpectomy

Abstract

An in vitro biomechanical study of the cervical spine. To evaluate the biomechanical significance of the posterior longitudinal ligament (PLL) after anterior cervical corpectomy and reconstruction with a strut graft and anterior plate. Routine excision of the PLL during anterior cervical corpectomy is controversial. Many surgeons believe that maintaining the PLL after cervical corpectomy adds stability to the reconstruction, whereas others believe it can be excised without sequelae. There are no biomechanical studies to our knowledge evaluating the biomechanical significance of excising the PLL during corpectomy and whether this affects the stability of a reconstruction consisting of a strut graft and anterior plate. The purpose of this study was to evaluate the biomechanical effects of PLL excision during a complete anterior cervical corpectomy reconstructed with a strut graft and anterior plate. Seven human cadaveric fresh-frozen cervical spines C2-T1 were tested for range of motion before surgery and reconstruction. A complete C6 corpectomy was performed and an interbody strut spacer with load cell was placed along with an anterior plate. Range of motion was measured with ±2.5 Nm of torque in flexion-extension, lateral bending, and axial rotation. Load-sharing data were recorded with incremental axial loads. The PLL was excised and range of motion and load-sharing testing was repeated. There were no significant differences in range of motion or load sharing with an anterior corpectomy and reconstruction after PLL excision. Excision of the PLL during anterior cervical corpectomy reconstructed with a strut graft and anterior plate does not significantly affect the construct stability or load sharing of the graft.