Incidence of Spontaneous Resorption of Lumbar Disc Herniation: A Meta-Analysis.

BACKGROUND: Lumbar disc herniation (LDH), a common disease, is often treated conservatively, frequently resulting in spontaneous resorption of the herniated disc. The incidence of this phenomenon, however, remains unknown.

OBJECTIVE: To analyze the incidence of spontaneous resorption after conservative treatment of LDH using computed tomography and magnetic resonance imaging.

STUDY DESIGN: Meta-analysis and systematic review of cohort studies.

SETTING: The work was performed at The Suzhou Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine.

METHODS: We initiated a search for the period from January 1990 to December 2015 using PubMed, Embase, and the Cochrane Library. Two independent reviewers examined the relevant reports. The references from these reports were also searched for additional trials using the criteria established in the PRISMA statement.

RESULTS: Our results represent the pooled results from 11 cohort studies. The overall incidence of spontaneous resorption after LDH was 66.66% (95% CI 51% - 69%). The incidence in the United Kingdom was 82.94% (95% CI 63.77% - 102.11%). The incidence in Japan was 62.58% (95% CI 55.71% - 69.46%).

LIMITATIONS: Our study was limited because there were few sources from which to extract data, either in abstracts or published studies. There were no randomized, controlled trials that met our criteria.

CONCLUSIONS: The phenomenon of LDH reabsorption is well recognized. Because its overall incidence is now 66.66% according to our results, conservative treatment may become the first choice of treatment for LDH. More large-scale, double-blinded, randomized, controlled trials are necessary to study the phenomenon of spontaneous resorption of LDH.Key words: Lumbar, disc herniation, spontaneous resorption, conservative treatment, incidence, country, meta-analysis, systematic review, observational studies, study designs.