Does histology predict the clinical outcome after lumbar intervertebral disc herniation: No

Background and objectivesThe histological analysis of extirpated intervertebral disc material from patients undergoing discectomy due to lumbar disc herniation remains an established procedure. In looking at whether the high costs that histological examination entails can be justified, it is worthwhile to ascertain the actual diagnostic benefit of this procedure. The aim of this study was to address the following hypothesis: Do histological characteristics such as the presence of inflammatory cells (macrophages) predict the clinical outcome of patients undergoing discectomy?Materials and methodsA total of 343 patients (221 males, 122 females, mean age 44.7 years) were treated microsurgically by root decompression subsequent to interlaminar fenestration. The patient history, the operated disc segment, the radicular and vegetative symptoms as well as the early and long-term outcome were evaluated. The excised disc material was classified histologically. CD68 staining was performed in 11 randomly chosen patients with good and in 11 patients with poor subjective long-term outcome for quantitative evaluation of macrophage count.ResultsThe follow up rate was 69.7%. Three hundred and five patients underwent disc surgery for the first time and 38 patients underwent relapse disc surgery. Moderate, pronounced and severe degeneration was found in 16, 231 and 92 patients, respectively. Positive subjective assessment of early outcome was 91% and 92% for the primary and relapse group, whereas long-term outcome was positive in 69% and 50% for the primary and the relapse group respectively. No histological features including CD68 (macrophage) count showed statistically significant correlations with the success of clinical treatment.Discussion and conclusionsA reliable prediction of the success of treatment, including patient outcome, cannot be made on the basis of the present histological criteria. The hypothesis must therefore be rejected.