Biomechanics of Disc Degeneration

Abstract

Disc degeneration and associated disorders are among the most debated topics in the orthopedic literature over the past few decades. These may be attributed to interrelated mechanical, biochemical, and environmental factors. The treatment options vary from conservative approaches to surgery, depending on the severity of degeneration and response to conservative therapies. Spinal fusion is considered to be the “gold standard” in surgical methods till date. However, the association of adjacent level degeneration has led to the evolution of motion preservation technologies like spinal arthroplasty and posterior dynamic stabilization systems. These new technologies are aimed to address pain and preserve motion while maintaining a proper load sharing among various spinal elements. This paper provides an elaborative biomechanical review of the technologies aimed to address the disc degeneration and reiterates the point that biomechanical efficacy followed by long-term clinical success will allow these nonfusion technologies as alternatives to fusion, at least in certain patient population.

Biomechanical Analysis Between PEEK and Titanium Screw-rods Spinal Construct Subjected to Fatigue Loading

“…Pressures within normal physiological range are critical in providing a suitable environment to maintain the function of the intervertebral disk cells and subsequently decreasing the risk rates of ASD. 2 Our findings support the merits of the PEEK construct in the spinal implants.…”

“…Such findings do provide a logical explanation for the increased risk for ASD observed clinically in this population. 2 In contrast, the PEEK rods group showed a comparable biomechanical pattern after fatigue loading to those of the intact group; therefore, it may represent a better capacity to reduce the nonphysiological loadings to the adjacent levels. Pressures within normal physiological range are critical in providing a suitable environment to maintain the function of the intervertebral disk cells and subsequently decreasing the risk rates of ASD.…”

“…1 Regardless of the pattern of instability or underlying pathology, most cases of clinical instability resulted in neural compression and clinical myelopathy requiring surgical intervention. 1,2 In the last few decades, spinal fusion with rigid type of screw-rod fixation utilizing Titanium alloys is becoming a standard care for spinal instability for its high fusion rates and immediate positive clinical outcome. 3 However, with the maturation of the technique, secondary complications have started to emerge.…”

Axial T1ρ MRI as a diagnostic imaging modality to quantify proteoglycan concentration in degenerative disc disease

“…Conventional magnetic resonance imaging (MRI) is useful for evaluating IDD but is often only sensitive to late-stage morphological changes in the IVD. As such there is a desire in the clinical community for a diagnostic tool that would better reflect physiological status of the IVD and quantifying IDD [1]. …”

Minimally Invasive Transforaminal Lumbar Interbody Fusion: Comparison of Isthmic Versus Degenerative Spondylolisthesis

“…Due to the interruption of the posterior elements, a lowgrade IS patient has an inherent instability that may result in greater anterolisthetic progression compared to a low-grade DS patient. [7][8][9][10] Often managed conservatively, a patient may experience refractory symptoms and elect to undergo surgical treatment, which often requires fusion surgery for definitive management. This can be accomplished in a variety of ways, one of which is minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF).…”