gms | German Medical Science

Objective: Microdiscectomy is considered to be the standard treatment for herniated lumbar discs. Some patients will experience post-operative back pain, and the potential sources for that pain are poorly understood. One potential source is the vertebral endplates and the disc. The goal of this study was to assess the changes that occur in lumbar endplates and disc following microdiscectomy and sequestrectomy in a long-term follow-up.

Method: Forty-six patients who had been operated at the lumbar spine for disc herniation at a mean of 32 years ago were evaluated. MRI exams were conducted in each patient. Changes in lumbar endplates and discs were assessed following Pfirrmann grading system and Modic grading. Further attention was given to the development of spinal canal stenosis and recurrent lumbar disc herniation.

Results: Forty-eight segments were examined among those three assessed Pfirrmann grade 3, eighteen grade 4, and 27 grade 5. The mean grade according to Pfirrmann was 4.6 in segment L5/S1, 4.4 in L4/5, and 3.6 in L3/4. The mean grade for all operated segments was 4.5, the mean grade for all non-operated segments was 2.9 according to Pfirrmann. In 24 cases (50%) Modic grade 2 changes were documented, mean Pfirrmann grading among those segments were 4.7. In ten of non-operated segments (5%) Modic changes were documented. In seven cases a recurrent disc herniation was documented. Spinal canal stenosis was documented in thirty-three patients, in twenty of those cases stenosis was seen above the operated segment.

Conclusions: Lumbar disc surgery is followed by worsening of disc signal intensity and decrease in disc height in all cases. New Modic changes were also observed in 50% of all cases. In 15% of cases recurrent disc herniation was observed. The degeneration of operated segments is substantial after more than 30 years compared to non-operated segments.