Biomechanical Effect of One-Level or Two-Level Minimally Invasive Posterior Cervical Foraminotomies

The option to treat unilateral cervical radiculopathy with minimal posterior cervical foraminotomy (PCF) surgery over the traditional anterior approach raises concerns due to the unknown changes that occur to the structural properties of the spine. The objective of this study was to determine the biomechanical stability of unilateral minimally invasive PCF performed at one or two levels in a human cadaveric cervical spine model. Five fresh human sub-axial (C2-T1) cadaveric cervical spines were biomechanical tested under a combined compressive force and flexion or extension bending moment. Three spine conditions were studied: harvested, one-level C5-C6 foraminotomy, and two level C5-C6 and C6-C7 foraminotomies. Measurements included global and individual motion segment unit (MSU) rotations and analyzed at an end load limit of 3Nm. Individual MSU contributions relative to global motion were statistically compared using a one-way repeated measures ANOVA and Student-Newman-Keuls test (P=0.05). No significant differences occurred in the total rotation or the segment rotational contributions between the three spine conditions in flexion testing or extension. From a biomechanical perspective, a one-level or two-level PCF is appropriate surgical option for treating cervical radiculopathy.