Effects of facet tropism and disk degeneration on far lateral lumbar disk herniation: comparison with posterolateral lumbar disk herniation.

Differences in facet tropism and disk degeneration were investigated as key factors distinguishing the development of far lateral lumbar disk herniation from that of posterolateral lumbar disk herniation in 46 patients with far lateral lumbar disk herniation individually matched with 46 patients with posterolateral lumbar disk herniation. Preoperative standing body height, body weight, and body mass index were compared. Facet tropism was measured using computed tomography and disk degeneration was evaluated using magnetic resonance imaging. Mean body mass index showed a significant difference between patients with the far lateral and posterolateral lumbar disk herniation (24.9 +/- 2.7 vs. 23.7 +/- 2.3 kg/m(2), p = 0.04). However, no significant differences were found in standing body height and body weight, facet tropism, or disk degeneration between two groups. Neither facet tropism nor disk degeneration are involved in distinguishing the development of far lateral lumbar disk herniation from that of posterolateral lumbar disk herniation.