Spontaneous Resorption of Lumbar Disc Herniation: A Narrative Review of Pathophysiology, Predictive Factors, and Clinical Decision-Making.

Lumbar intervertebral disc herniation is a common cause of low back and radicular leg pain, traditionally managed with a combination of conservative therapies and, when indicated, surgical discectomy. An intriguing phenomenon observed in many patients is the spontaneous resorption of herniated disc material over time, often correlating with significant symptom improvement. This article is presented as a narrative review synthesizing experimental, imaging, and clinical literature relevant to spontaneous disc resorption and its implications for clinical decision-making. This paper provides a comprehensive overview of spontaneous disc herniation resorption, exploring the underlying pathophysiological mechanisms and the factors that predict which herniations are likely to regress without surgery. Key mechanisms include inflammatory-mediated degradation of disc fragments, neovascularization with macrophage infiltration and phagocytosis of extruded nucleus pulposus tissue, and biological processes such as enzymatic matrix breakdown and cellular apoptosis that collectively lead to shrinkage of the herniated mass. Patient and disc characteristics that favour spontaneous resorption are identified, such as younger age, extruded or sequestered fragment type, larger initial herniation size, and robust inflammatory response on imaging, whereas certain chronic degenerative changes may reduce this likelihood. We also review current clinical guidelines and expert recommendations on when surgical intervention is warranted versus when conservative management and observation are appropriate. Understanding the probability of natural disc fragment resolution is critical in guiding treatment decisions. In the absence of severe neurological deficits or intractable pain, a period of non-operative management can often be pursued safely, given that the majority of patients experience substantial relief within a few months as discs regress. Conversely, timely surgery is advised for those with neurological compromise or refractory symptoms. By synthesizing the latest evidence on spontaneous disc herniation resorption and its predictors, this review aims to assist neurosurgeons and spine specialists in optimizing patient selection for conservative care and identifying the proper timing for surgical intervention to achieve the best clinical outcomes. Given the narrative design, conclusions are based on synthesis of heterogeneous evidence rather than formal comparative analysis.