Frequency of Lumbar Intervertebral Disc Calcification and Angiogenesis, and Their Correlation With Clinical, Surgical, and Magnetic Resonance Imaging Findings

Study Design. This study measured the frequency of lumbar intervertebral disc nucleus pulposus microscopic calcification and angiogenesis in adult patients undergoing discectomy compared to normal cadavers. Objective. The results were compared to determine the relationship between disc microscopic calcification with disc degeneration type, histopathological angiogenesis, patients' age, gender, and duration of symptoms. Summary of Background Data. True frequency of microscopic calcification in normal or degenerated lumbar discs have not been fully defined nor linked to disc degeneration type and angiogenesis. Some studies demonstrated that angiogenesis and calcification are related to each other in several another tissues. Methods. The frequency of microscopic calcification in specimens of disc nucleus pulpous obtained from 2 groups were measured: specimens were obtained during surgery from 90 consecutive patients of 15 to 50 years old suffering from disc herniation in single level of L4-L5 or L5-S1 between 2005 and 2006, 60 additional specimens of lumbar disc nucleus pulposus were obtained from normal cadavers of the same ages. Calcification was determined microscopically by Von Kossa staining and angiogenesis by H/E, and type of degeneration radiologically by Modic classification. Results. Frequency of microscopic calcification was significantly higher in degenerated disc than normal cadaveric (54.4% vs. 6.7%) and was higher in Modic type III than type I (III: 95.0%, II: 57.4%, I: 13.0%), also prevalence of angiogenesis was significantly higher in patients than cadaveric discs (41.0% vs. 6.7%) and in calcified than noncalcified discs (59.2% vs. 19.5%) (P < 0.001). There was no relationship between disc calcification and patients' gender and level of discectomy. Conclusion. Disc nucleus pulposus microscopic calcification is a common event occurring in adult patients suffering from lumbar disc herniation. Mechanisms that link disc degeneration, angiogenesis, and calcification remain a focus for further researches that may be useful in future medical treatments before surgical treatment of lumbar disc herniation.