Current Understanding of Lumbar Intervertebral Disc Degeneration: A Review With Emphasis Upon Etiology, Pathophysiology, and Lumbar Magnetic Resonance Imaging Findings

Abstract

The lumbar intervertebral discs (IVDs) are of critical importance for the support and mobility of the spine. 16,54,71 These remarkable tissues have the capacity to maintain stability under a wide variety of loading conditions, while still permitting intersegmental motion. 7,16 Unfortunately, the lumbar IVDs undergo more destructive changes over a lifetime than do any other musculoskeletal tissues 53 and often contribute directly, or indirectly, to the symptoms of low back pain and sciatica. 61,62,90,91 decades. 18,44,51,53 Not surprisingly, DD is the most common condition affecting the adult spine and is the reason for over 90% of all adult spinal surgeries. 8Although exact data are lacking, it is quite likely that a high percentage of adults seeking physical therapy care for low back pain and/or sciatica will have imaging evidence of lumbar DD at 1 or more spinal levels. The exact role that these findings play in symptom generation is, however, often unknown. For example, several population-based or case control studies have also reported a high prevalence of DD in asymptomatic people. 19,57,97 This has led to a lack of consensus regarding the importance of the presence of DD relative to determining patient prognosis and treatment.Over the past several years, a growing body of evidence has provided valuable information regarding the etiology of lumbar DD 6,13,50,105,116 and the pathophysiology of the degenerative lumbar IVD. 5,27,58,70,94,99,101 This information will assist clinicians and researchers in understanding the development and clinical course of lumbar DD and its potential impact upon patients seeking physical therapy care for back pain. Although abnormalities of the lumbar IVD can manifest in many different ways, such as bulging or herniation, the common central feature to most disc pathology is the process of specific degenerative changes that occurs within the nucleus, annulus, and adjacent bony tissue. 5,8,98 This complex process of cell-mediated structural changes occurs over a lifespan, with signs of disc degeneration (DD) often present by the third decade of life, and almost universal by the seventh and eighth SYNOPSIS: Degeneration of the lumbar intervertebral discs (IVDs) is highly prevalent in adults and nearly universal in the elderly population. Degenerative changes within, and adjacent to, the IVDs are likely to contribute to a variety of pain syndromes; however, the exact association between these findings and symptoms remains speculative. Recent research has provided new information regarding the etiology, pathophysiology, and clinical relevance of degeneration of the IVD. This information will assist clinicians and researchers in understanding the development and clinical course of lumbar disc degeneration, as well as its potential impact upon patients seeking physical therapy care for back pain. The purposes of this clinical commentary are to review the structure and metabolic capacity of the normal and degenerative lumbar IVD, and to discuss factors that influence the onset and progr...

Interference in the endplate nutritional pathway causes intervertebral disc degeneration in an immature porcine model

“…Compared to the normal controls, NP T2 values significantly declined in the cement-blocked discs. This result was consistent with previous studies [2,3] where the lower T2 value reflects more severe disc degeneration, and reductions in T2 values indicate reduction of ECM and water content. We were able to conclude that the cementblocked discs were pathologically degenerated.…”

“…IDD changes start in childhood and may cause biomechanical disc dysfunction and low back pain symptoms later in life [3]. While the pathology of IDD is not fully understood, insufficient nutritional supply to the disc has been proposed as a possible initiator of IDD [4].…”

Diffusion-Weighted Magnetic Resonance Imaging of the Musculoskeletal System: An Emerging Technology With Potential to Impact Clinical Decision Making

“…23,62 This phenomenon helps to maintain homeostasis by allowing the cells within the musculoskeletal system to receive oxygen and nutrients and to eliminate metabolic biproducts. 10,21,63 The magnitude of diffusion is greatly influenced by the size of the gradient between the points of interest. These gradients can occur due to differences in the concentrations of water, circulating proteins, and electrolytes (FIGURE 1).…”

“…Although there are many reasons for this difficulty, a primary barrier has been the high prevalence of structural variations in the osteocartilaginous spine observed in asymptomatic and symptomatic individuals, and the inability of conventional imaging procedures to determine which findings are linked to symptoms. [9][10][11][12][13][14]18,40 Recent studies using DWI have helped to clarify differences among and between patients with spinal problems by highlighting trends toward altered diffusion in various diseased or injured spinal tissues. 1,[7][8][9][10][11][12]16 These observations have provided new insight into the etiologies and the effect of interventions for certain subsets of patients with spinal disorders.…”

“…57 In other instances, changes in diffusion can be an unfavorable event, resulting from disease or trauma, and manifests as hematomas, inflammatory responses, edema, neovascularity, or solid tumors. [7][8][9][10]16,24,25 The application of DWI can help to clarify the presence and nature of these events.…”