Study Design. Fifty-five consecutive patients undergoing microdiskectomy due to lumbar disc herniation were included in this clinical study over 12 months.Objectives. To investigate possible correlations between the histologic composition of the herniated disc fragments and pain, disability, clinical signs, and operative findings.Summary of Background Data. Previous studies have investigated the histologic composition of herniated lumbar disc fragments. Few publications, however, examined correlations with clinical data.Methods. Before treatment, patients were examined using a standardized clinical protocol; subjective disability and pain were assessed by the Oswestry Disability Questionnaire and the McGill Pain Questionnaire. The herniated disc fragments were examined semiquantitatively for the relative percentages of nucleus pulposus, anulus fibrosus, and cartilaginous endplate.Results. In patients less than 30 years of age, significantly higher percentages of nucleus pulposus were found than in the older group, whereas anulus fibrosus was found in significantly higher percentages in patients Ն30 years. Both higher percentages of cartilage and nucleus pulposus correlated with increased pain intensity values from the McGill Pain Questionnaire. Impaired reflexes before treatment occurred significantly more often in patients with Ն20% of cartilage in the herniated fragments. If nucleus pulposus was Ͻ30%, sensory impairment tended to be more severe before treatment.Conclusion. The histologic composition of the herniated disc fragments seems to affect pain and clinical symptoms.The histologic composition of herniated disc fragments has been subject to many publications. 1-11 Few attempts have been made, however, to correlate histologic findings with clinical data. 2,6,8 There have been publications indicating a relationship between the magnitude and onset rate of compression and nerve root lesions. 12-19 Intraneural edema formation was shown to be more pronounced after rapid than after slow onset of compression. 14 A significant correlation was observed between compression pressure and duration on spinal nerve root conduction deficit, with significant differences between efferent and afferent fibers. 13,16,18 Based on these studies, the assumption could be made that "harder" herniations consisting mainly of cartilage endplate and/or anulus fibrosus might result in more aggressive nerve root irritation than "softer" ones composed mainly of nucleus pulposus. Therefore, we performed a clinical study to investigate possible relationships between the relative percentages of nucleus pulposus, anulus fibrosus, and cartilaginous endplate and the clinical symptoms, the subjective disability, and the pain suffered by the patients concerned. Methods Patients.This study comprised a consecutive series of 55 patients (17 women, 38 men) who underwent microdiskectomy for lumbar disc herniation over a period of 12 months. The age ranged from 17 to 71 years (mean 43 years).Although L2-L3 was concerned in only 1 patient (2%), 24 patie...