The Change of Lumbar Facet Joint Motility in the Degenerative Process

Park, Seung Won; Kwon, Jeong Taik; Kim, Young Baeg; Min, Byung Kook; Hwang, Sung Nam; Choi, Duck Young; Suk, Jong Sik

Abstract

The areas of lumbar intervertebral foramina(IVF) were measured from flexion and extension lateral plain films to study the facet joint motility in the degenerative process of lumbar spine. By studying the facet joint motility, the authors tried to determine whether the aging or degenerative process would make the facet joints slack or stiff. This study involved 10 patients with radiographic instability with or without grade I spondylolisthesis at L4-5 who had underwent fusion operaion, and 45 patients with only transient low back pain with normal radiographic findings. The patients with low back pain only were divided into goups I-V according to their ages. Those with spinal instability was grouped as VI. The areas(mm2) of IVF at flexion and extension and the changes of IVF areas((IVF area at flexion-IVF area at extension)/IVF area at flexion) were measured at L1-2, L2-3, L3-4, and L4-5 levels by using image analyzing program(Optimas 5.2(r)). The IVF areas were significantly narrower at extension than flexion(p<0.01). The major factors affecting the IVF areas at flexion or extension were the posteroinferior or anterosuperior displacement of superior articular process of the inferior vertebral body, respectively. The changes of IVF areas with motions were greatest at the L4-5 and least at the L1-2 level. In group V(over 50 years of age), the areas at IVF at flexion and the changes of the area with flexion and extension were significantly decreased at the L4-5 level compared with younger age groups(p<0.05). In group VI, the areas of IVF at flexion and the changes of the area were significantly decreased at L3-4 and L4-5 levels compared with the other groups(p<0.001). As a result, we concluded that the changes of IVF area decreases with aging and degenerative process resulting in facet joint stiffening.