Two trajectories of lumbar disc degeneration from adolescence to adulthood: a 23-year longitudinal MRI study

Disc degeneration (DD) increases with age, but its onset and early progression remain poorly understood. This longitudinal study examined DD progression from adolescence into adulthood in healthy individuals.

Forty participants with magnetic resonance imaging (MRI) at ages 11, 19, and 34 were included. Discs were graded using the Pfirrmann classification, and a Pfirrmann Summary Score (PSS, range 5-25) was calculated by summing individual disc grades. The primary outcome was progression of overall DD burden, defined as an increase in PSS. Participants were grouped by PSS at age 11: PSS = 5 (later-onset) vs. PSS 6 or higher (early-onset). Presence of at least one disc graded Pfirrmann 3 or higher was assessed at ages 19 and 34.

Demographics, anthropometrics, and clinical characteristics were comparable between the groups. All participants showed DD progression. Early-onset individuals had higher PSS at ages 19 and 34, whereas later-onset individuals exhibited greater PSS change over time. By age 19, early-onset participants more frequently had at least one Pfirrmann 3 or higher disc; by age 34, occurrence was similar (72% vs. 73%). Later-onset DD was localized to lower lumbar spine, whereas early-onset DD was more widespread. DD progression trajectories were not associated with low back pain (LBP) by age 34.

Progression of DD is an inevitable but individually variable process. Early-onset DD appears to lead to a more widespread pattern, whereas later-onset DD progresses more rapidly but remains confined to the lower lumbar spine. No direct relationship between structural progression and LBP could be determined.