Introduction: The cartilaginous endplate (CEP) holds the key to the health of the disc end plate bone marrow complex as it forms the immediate layer, adherent to the nucleus pulposus, and maintains the structural integrity of the visco-elastic nucleus pulposus. The paucity of studies on the cartilaginous end plate is due to the inability to visualise the CEP as a separate and integral structure in the usually performed T1 and T2 sequences. Hence, we utilised the Fast Low Angle Shot (FLASH) sequence to document the sequential changes in cartilaginous (CEP) and bony end plate (BEP) to study the influence on disc degeneration (DD).
Methods: Routine MRI and FLASH sequences were used in 500 lumbar discs in 100 each of healthy volunteers (HV), low back pain patients treated conservatively (CG) and surgically (SG) to document CEP and BEP status, Pfirrmann Grade (PG) and various MRI parameters.
Results: The three groups were identical demographically but had a significantly different number of healthy discs (p<0.01) and changes in CEP and BEP (p<0.01), with patients having a higher severity of end plate changes and DD, even in asymptomatic discs. CEP abnormalities always appeared first, followed by a sequence of BEP defects of different severity, allowing the development of an ‘Integrated Total End Plate Score’ (I-TEPS). There was a good correlation between I-TEPS and PG, with a steep escalation of DD after a score of 7. A score of >7 was also associated with higher surgical incidence in patients with both degenerated and herniated discs. The most significant influencing factors for surgery were a combination of I-TEPS > 7 with protrusion (OR 7.7; p-0.00), smoking (OR4.63; p-0.02), and an I-TEPS > 7 (OR3.37; p-0.04).
Conclusion: CEP changes identified by FLASH preceded BEP defects and DD. I-TEPS was superior to TEPS in identifying a subgroup of discs that had CEP abnormalities without BEP. An I-TEPS >7 had a significant correlation to the severity of DD, influenced variations in herniation and also surgical incidence.