Isthmic Spondylolisthesis and Degenerative Spondylolisthesis

Peer Reviewed

Lumbosacral SpineIsthmic spondylolisthesis should be differentiated from degenerative spondylolisthesis. Degenerative spondylolisthesis occurs due to the aging process along with the development of marked facet joint arthritis with rotatory vertebral slip. Degenerative spondylolisthesis occurs mostly at the L4-L5 (fourth and fifth lumbar vertebrae) level as opposed to its isthmic counterpart, which occurs most often at the lumbosacral level (L5-S1).

Although in most instances spondylolisthesis develops before adulthood, only 25% of children and adolescents experience symptoms such as back pain and/or buttock and thigh pain, especially in patients with a high-grade slip. Many adults are unaware of their spondylolisthesis until it becomes symptomatic. Symptoms usually begin to occur between the ages of 30 and 50 years. This raises an interesting question:

If spondylolisthesis is a developmental condition that occurs in late childhood or adolescence and seldom after the age of 20, why is it clinically silent in so many adults until midlife?

The lumbosacral joint is subjected to considerable anterior-directed shear forces. The paired facet joints, pars interarticularis, and intervertebral disc are the main anatomical structures that resist these forces. In the presence of spondylolysis, with or without mild spondylolisthesis, the facet joints become unable to resist the anterior shear forces.

In the presence of spondylolysis, the intervertebral disc is the main structure that retains the stability of the segment. As long as the disc is capable of maintaining its biomechanical and biochemical integrity, mild spondylolisthesis will be stable, despite the presence of a mild slip and the loss of resistance to shear forces provided by the posterior vertebral structures. Once the disc degenerates, the main source of stability is lost and the vertebral slip increases, leading to symptoms of back and leg pain.

Updated on: 09/15/15
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Isthmic Spondylolisthesis: Adult Slip Progression
David S. Bradford, MD

Isthmic spondylolisthesis is an important cause of back pain and disability in children, adolescents, and adults. The natural history and clinical presentation of isthmic spondylolisthesis is distinct from other etiologies of spondylolisthesis. Dr. Floman has made an important contribution to our understanding of isthmic spondylolisthesis in adults by demonstrating a significant incidence of deformity progression in adulthood, and suggesting a mechanism to explain the variable onset of pain associated with spondylolisthesis in adults. (1) Operative management in the patient with symptomatic isthmic spondylolisthesis is clearly superior to non-operative care. (2) However, there remains significant variation in surgical strategies, and limited evidence to guide decision-making.

In low-grade isthmic spondylolisthesis, the role of anterior column support has not been well-defined, and there is little consensus on circumferential arthrodesis compared with posterolateral fusion alone. In fact, a beneficial effect of instrumentation has not been clearly established in these cases. (3) In contrast, in grade 3 and 4 spondylolisthesis, there is strong evidence to suggest improved rates of arthrodesis and better clinical outcome with structural support of the anterior column. (4) In high-grade spondylolisthesis, partial reduction and transosseous fixation has resulted in reliably good clinical outcomes. (5) The role of complete reduction and restoration of lumbopelvic relationships remains to be established.

Dr. Floman's observation that the surgical treatment of symptomatic isthmic spondylolisthesis is a reliable procedure for the treatment of pain and dusfunction is confirmed by our published and unpublished data. (5,6,7) Further investigations including multicenter prospectve clinical studies are required to establish an evidence-based consensus approach regarding the role of interbody arthrodesis in low-grade spondylolisthesis, the role of reduction of slippage and restoration of lumbosacral lordosis in high-grade spondylolisthesis, and the role of in-situ arthrodesis in adults.

1. Floman, Y. Spine. 2000;25(3):342-7.
2. Moller H, Hedland R. Spine. 2000;25(13):1711-5.
3. Moller H, Hedland R. Spine. 2000;25(13):1716-21.
4. Molinari RW, et al. Spine. 1999;24(16):1701-11.
5. Smith JA, et al. Spine. 2001;26(20):2227-34.
6. Bradford, DS. J Bone Joint Surg Am. 1990;72(7):1060-6.
7. Butterman GR, et al. Spine. 1998;23(1):116-27.


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Isthmic Spondylolisthesis: Adult Slip Progression

In the last decade, adult onset slip progression, spondylolisthesis, was recognized and described in the medical literature as a distinct clinical entity causing severe incapacitating back and leg pain.
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