Abstract
PURPOSE: In patients with lumbar disc herniation (LDH), the herniated intervertebral disc (IVD) can be spontaneously absorbed without surgical intervention (herein referred to as "resorption"). However, current studies provide unclear explanations of the mechanism of LDH resorption, and the summary of predictive factors is not comprehensive enough. This review aimed to summarize predictive factors associated with LDH resorption based on current evidence, thereby providing clinical guidance for therapeutic decision making. METHODS: A comprehensive literature search was performed using PubMed, Web of Science, Embase, and the Cochrane Library from database inception to July 2024. The search was performed using the terms "spontaneous", "regression", "resorption", "remission", "absorption", "herniation", and "disc". Manual searches were also performed to broaden the literature search. Studies were included if they reported at least one potential predictor of resorption in patients with LDH and provided follow-up imaging assessments (CT/MRI) to define resorption outcomes, along with the criteria used to determine the presence or absence of imaging resorption. Two reviewers independently searched the relevant literature and the ROBINS-I tool were used to assess the quality. RESULTS: The literature search yielded 1115 publications, of which 22 were finally included. The review suggested that the probability of resorption in LDH can be predicted by five aspects: clinical factors, type and size of the LDH, composition of the herniated IVD, imaging features of LDH, and spinal physiology. One limitation of this review is the lack of high-quality prospective studies among the included research, which may affect the accuracy of the findings. CONCLUSION: The probability of resorption in LDH can be predicted based on five aspects. This helps clinicians preferentially select LDH cases with a high probability of resorption for conservative treatment, which is of positive significance for improving the success rate of conservative treatment in patients with LDH. However, due to the lack of high-quality prospective studies for support, large-scale prospective studies are necessary to assess the accuracy of these predictive factors for LDH resorption.