Familial predisposition for lumbar degenerative disc disease. A case-control study

Abstract

Study design: A case-control study using magnetic resonance imaging and plain radiography to evaluate whether a family history of lumbar disc herniation is a risk factor for disc degeneration.

Objectives: To evaluate the significance of a family history of operated lumbar disc herniation in the development of lumbar disc degeneration and lumbar disc herniation.

Summary of background data: There are only a few epidemiologic studies indicating that a family history of intervertebral disc herniation is a risk factor for juvenile disc herniation. Recently, similarities in degenerative findings of the lumbar spine between identical twins have been reported.

Methods: In the case group, 24 patients who were the immediate relatives of patients who had undergone surgery for disc herniation and who presented or had a history of low back pain and/or unilateral leg pain were included. Control individuals included 72 age- and gender-matched outpatients who reported low back pain and/or leg pain without a family history of operated disc herniation. The incidence, level, and topographic location of disc herniation/diffuse bulge; the incidence and grade of disc degeneration observed on magnetic resonance images; and degenerative changes suggesting disc degeneration observed on plain radiographs were compared between the relatives of patients with disc herniation (cases) and the controls.

Results: The incidence of disc degeneration at L4-L5 and L5-S1 in cases (L4-L5, 18/24; L5-S1, 18/24) and controls (L4-L5, 45/72; L5-S1, 43/72) was similarly high. However, the grade of disc degeneration according to magnetic resonance imaging signal intensity on the T2-weighted sagittal image using Schneiderman's four-grade classification was significantly more severe in cases (L4-L5: Grade 1, 6/24; Grade 2, 4/24; Grade 3, 13/ 24; Grade 4, 1/24; L5-S1: Grade 1, 6/24; Grade 2: 3/24, Grade 3: 12/24, Grade 4: 3/24) than in controls (L4-L5: Grade 1, 27/72; Grade 2, 24/72; Grade 3, 20/72; Grade 4, 1/72; P = 0.034; L5-S1: Grade 1, 29/72; Grade 2, 23/72; Grade 3, 13/72; Grade 4, 7/72; P = 0.023; Mann-Whitney U test). The incidence of disc herniation/diffuse bulge at L4-L5 (16/24) and L5-S1 (11/24) in cases was higher than that in controls (L4-L5, 33/72; P = 0.07; L5-S1, 17/ 72; P = 0.04; chi-square test).

Conclusion: The current study provided evidence that a family history of operated lumbar disc herniation has a significant implication in lumbar degenerative disc disease. There may be a genetic factor in the development of lumbar disc herniation as an expression of disc degeneration.