Introduction: Symptomatic lumbar disc herniation can occur in any age group and population worldwide. The socioeconomic burden of such an occurrence is substantial. Oftentimes, the LDH can undergo a process of “self-healing” and resorb. However, the degeneration profile of the disc following herniation and resorption remains unknown. As such, this study aimed to examine the “Disc Degeneration Profile” of the LDH following resorption and further investigate associated imaging and clinical risk factors.

Methods: A one-year prospective study was conducted of patients presenting with acute, symptomatic LDH. All patients were managed conservatively by a single clinician. Baseline assessment included patient demographics, herniation characteristics (e.g., herniation size, location, geospatial measurements), and MRI phenotypes (e.g., disc degeneration, endplate abnormalities, vertebral body dimensions). MRIs were performed at initial presentation and approximately every 3 months until symptom resolution or disc resorption on imaging. Disc degeneration was quantified by the Pfirrmann classification system, whereby grades were given to each LDH for MRI obtained, from which a “Disc Degeneration Profile” for each patient was constructed. Group 1 represented patients that had stable/improving discs (i.e. no further disc degeneration throughout follow-up) and Group 2 represented discs with worsening degenerative changes.

Results: 93 patients were included (Group 1 [n=82 stable/n=1 improving]; Group 2 [n=10 worsening]). The mean age was 47.7±12.3 and 49.0±11.9 years for Groups 1 and 2, respectively. Baseline demographics, herniation characteristics, and alignment measurements did not differ between groups. On follow-up, those in Group 1 were more likely to have greater reduction in sagittal disc size compared to those in Group 2 (p=0.018). Patients in Group 1 exhibited greater change in their Cobb angles compared to Group 2 (p=0.037). Patients in Group 1 were also more likely to have greater L3 anterior body disc height (p=0.028) and L4 inferior body disc width (p=0.029). Group 1 had higher incidence of index disc grades, greater disc degeneration scores at MRI-1 (p=0.001) and MRI-3 (p=0.039), higher incidence of Schmorl’s nodes above the herniation level (p=0.016) and greater incidence of endplate damage above (p=0.011) as well as below herniation level (p=0.008) compared to Group 2. No differences in resorption rate or time to resolution were observed between those with Group 1 and Group 2, however, those in Group 1 where more likely to have greater amounts of pain medication compared to Group 2 (p=0.029).

Discussion: This is the first study to have noted the fate of the “Disc Degeneration Profile” in symptomatic LDH patients that had disc resorption within one year since herniation. Interestingly, those with “stable” degeneration profiles were more likely to have not only degenerative changes (e.g., endplate damage) but required greater amounts of pain medication as well, which may be secondary to the fact that these individuals initially presented with worse disc degeneration. Moreover, this study indicates vertebral dimensions may provide insight into overall disc health.  Information of the Disc Degeneration Profile of the LDH patient will assist clinicians in managing patient expectations and perhaps developing more personalized spine care with long-term patient assessment for future sequelae.