Adjacent Disc and Facet Joint Degeneration in Young Patients with and Without Lumbar Spondylolytic Spondylolisthesis: A MRI Retrospective Study
Introduction: Unlike adjacent segment disease associated with vertebral fusion, early adjacent disc degeneration can be found on magnetic resonance imaging (MRI) of children and adolescents with spondylolytic spondylolisthesis who have not undergone spinal fusion. Furthermore, in this age group, patients who are symptomatic with spondylolytic spondylolisthesis exhibit adjacent degeneration on MRI.
In adults, adjacent level degeneration is seen on axial MRI studies of patients with degenerative spondylolisthesis.
Purpose: The purpose of this retrospective study was three-fold. (1) Determine if disc and facet joint degeneration at the olisthetic and adjacent levels was appreciably different in young patients with and without spondylolisthesis. (2) Evaluate the effect of spondylolytic spondylolisthesis on the degeneration of the disc and facet joint at the olisthetic and adjacent levels. (3) Dismiss the potentially unclear effect of aging.
Methods: A case group and a reference group were collected.
- Group 1: The case group involved the medical records of 35 patients (29 men, 6 women); average age was 23.4 years (range: 16-29 years). Each study participant had low grade spondylolytic spondylolisthesis (Grade 1: n=31, Grade 2: n=4). Mean shippage was 15.2%. Thirty-three patients had low back pain and 20 had sciatica.
- Group 2: The reference group involved 50 patients (31 men, 19 women); average age was 23.7 years (range: 20-29 years). This group had disc herniation at L5-S1 with either low back pain (n=42) or sciatica (n=36) but no spondylolisthesis.
Both groups of patients underwent lumbar MRI evaluation between January 2005 and September 2009. MRI studies included sagittal T1-weighted and STIR sequences, and axial T1- and T2-weighted sequences. Each spondylolisthesis was measured from the sagittal MRI, sagittal STIR images were used to grade the disc degeneration, and the extent of disc degeneration was based on Pfirrmann grading system. Axial T2-weighted MRIs and Grogan’s classification were utilized to evaluate facet joint degeneration.
Results: Severe disc and facet joint degenerative changes at L3-L4 and L4-L5, and olisthetic levels L5-S1 in the case group compared to the reference group. In the case group, a trend was noted. Disc and facet joint degeneration was greatest at the olisthetic level and became less in adjacent levels away from the pars defect.
Hsieh CC, Wang JD, Lin RM, Lin CJ, Huang KY. Adjacent Disc and Facet Joint Degeneration in Young Adults with Low-grade Spondylolytic Spondylolisthesis: A Magnetic Resonance Imaging Study. Journal of the Formosan Medical Association. 2014;xx:1-5.
This retrospective MRI study addresses the question of whether patients with spondylolytic spondylolisthesis have an increased incidence of adjacent level degeneration when compared to patients with symptomatic disc herniation but normal anatomy. The authors found a positive correlation of increased degenerative change at adjacent facet joints in the patient group when compared to the control group. Hsieh et al reasoned that the pars defect is, in effect, a nonunion, which places additional stresses on the adjacent restraining structures; facet joints and intervertebral disc leading to early degenerative changes.
Furthermore, the authors concluded that early pars defect repair can be considered in asymptomatic patients to prevent early degenerative changes and worsening of a spondylolisthesis.