Clinical Manifestations and MRI Findings of Patients with Hydrated and Dehydrated Lumbar Disk Herniation

Background and Objective: In addition to the ex-pected appearance of degenerated disks which be-come dehydrated, hydrated intervertebral disk herni-ations are sometimes encountered in radiologic prac-tice. This study was undertaken to evaluate the clini-cal manifestations and MRI findings of hydrated and dehydrated herniated intervertebral disks. Materials and Methods: This cross-sectional single institution study included 73 patients with dehy-drated (group I) and hydrated (group II) lumbar disk herniation. The criteria for hydrated and dehydrated disk herniation was a subjective criteria compared to the normal signal of intervertebral disks. A herniated disk has been regarded to be hydrated if more than 2/3 of it was hypersignal in T2-weighted images, while more than 2/3 of a dehydrated disk was hy-posignal on T2-weighted images. Results: Mean weight of patients in group I was greater than patients in group II (69.3 vs. 64.2, P<0.05). In addition, patients in group I tend to be older than group II (35.2 vs. 28.9, P<0.05). Consider-ing physical activity, a greater number of patients in group II had intense physical activity compared to group I (25% vs. 13.2% respectively, P<0.05). The duration of radicular pain and back pain was signifi-cantly greater in group I than in group II (485 vs. 202 and 1346 vs. 242 respectively, P<0.05). Conclusion: Hydrated intervertebral disk herniation tends to be associated with younger age, lighter body weight, shorter duration of radicular pain and more intense physical activity compared to dehydrated in-tervertebral disk herniation. These findings may sug-gest other mechanisms rather than degenerative changes for hydrated disk herniation.