Relationship between the histological findings of spondylolytic tissue, instability of the loose lamina, and low back pain

L5 spondylolysis: Anatomical study comparing healed and unhealed lesions

The anatomy and pathogenesis of spondylolysis has been widely studied; however, the microanatomy of spondylolysis of the lumbar vertebra has not been well described. Therefore, we aim to better elucidate this anatomy. Twenty dry bone specimens of healed and unhealed spondylolysis of the L5 vertebra were collected from human skeletal remains. Twelve L5 vertebrae were examples of unhealed spondylolysis and eight specimens exhibited a healed (i.e., bony fusion of the lesion) spondylolysis lesion. The specimens underwent macro and microanatomical analysis followed by CT and microCT imaging. Finally, selected healed and unhealed lesions were submitted for histological analysis using Mason Trichrome staining. The pars interarticularis of two L5 vertebrae without signs of healed/unhealed spondylolysis were evaluated histologically as controls. Of the 12 unhealed L5 pars defects, three were unilateral on left side. Of the eight healed pars defects, all were unilateral and seven of these were on left sides. One unilateral pars defect also had spina bifida occulta. Both on imaging and histological analysis, healed pars defects were only so superficially and not at deeper levels. Histologically, unhealed edges were made up of dense cortical bone while healed edges were made up primarily of trabecular bone. Based on our anatomical findings, the so-called healed spondylolysis lesions, although externally fused, are not thoroughly fused internally. Moreover, the anterior and posterior edges of the unhealed spondylosysis lesions are irregular and show signs of long-term disarticulation. Taken together, these data suggest that such 'healed' lesions might not be as stable as the normal L5 pars interarticularis.

Usefulness of discography, discoblock and a new mechanical method for identifying a painful segment/disc

BACKGROUND

We previously described a procedure for eliciting deep spatial discrimination of individual segments in the healthy lumbar spine of normal subjects: the percutaneous mechanical provocation (PMP) test. Our goal was to devise a method for accurate identification of the spinal level of pathology in chronic low back pain (CLBP). In the present study, we validated the PMP test, using a subgroup of CLBP patients with isthmic spondylolisthesis (IS). Because there is clinical consensus that IS back pain originates in the slipped segment/disc, the level of pathology can be directly compared to the result of the PMP test. The test is agnostic with respect to the underlying pathological mechanism, and therefore might be useful in identifying the involved segment(s) irrespective of the painful structure.

METHODS

In 37 patients with confirmed IS (slippage 3-15mm), we compared sensitivity between the PMP test, the widely used provocative discography test and the discoblock test.

RESULTS

The PMP test reliably identified the slip level in patients with IS, with sensitivity of 92%. Accepting the slipped disc as the origin of pain in IS, the sensitivity of the provocative discography and discoblock tests were 49% and 35%, respectively: i.e., too low to be contributive in clinical practice.

CONCLUSIONS

The PMP test reliably identified the origin of localized pain in IS as the slip level, but should be used with care in CLBP patients in selecting discogenic pain patients for fusion surgery, since the specificity of the test is not known and it may be positive for any origin of localized pain.

Sensory nerve ingrowth, cytokines, and instability of discogenic low back pain: A review

Introduction

Many patients suffer from discogenic low back pain. However, the mechanisms, diagnosistic strategy, and treatment of discogenic low back pain all remain controversial. The purpose of this paper was to review the pathological mechanisms of discogenic low back pain.

Methods

Many authors have investigated the pathological mechanisms of discogenic low back pain using animal models and examining human patients. Central to most investigations is understanding the innervation and instabilities of diseased intervertebral discs and the role of inflammatory mediators. We discuss three pathological mechanisms of discogenic low back pain: innervation, inflammation, and mechanical hypermobility of the intervertebral disc.

Results

Sensory nerve fibers include C-fibers and A delta-fibers, which relay pain signals from the innervated outer layers of the intervertebral disc under normal conditions. However, ingrowth of these sensory nerve fibers into the inner layers of intervertebral disc occurs under disease conditions. Levels of neurotrophic factors and some cytokines are significantly higher in diseased discs than in normal discs. Stablization of the segmental hypermobility, which can be induced by intervertebral disc degeneration, suppresses inflammation and prevents sensitization of sensory nerve fibers innervating the disc.

Conclusions

Pathological mechanisms of discogenic low back pain include sensory nerve ingrowth into inner layers of the intervertebral disc, upregulation of neurotrophic factors and cytokines, and instability. Inhibition of these mechanisms is important in the treatment of discogenic low back pain.

Classification of spondylolytic clefts in patients with spondylolysis or isthmic spondylolisthesis using positional MRI

Background Posterior instability is a pathologic movement occurring in the spondylolytic cleft. Purpose To present a new classification system for the evaluation of spondylolytic cleft by positional magnetic resonance imaging (MRI) and determine the prevalence of the different types. Material and Methods A total of 176 segments of the lumbar spine with spondylolysis or isthmic spondylolisthesis were examined using positional MRI. Scans were obtained in neutral sitting, flexion, and extension positions. No visible movement in the cleft was defined as type A, fluid displaced into the cleft as type BI, displacement of the flava ligaments at the level of the cleft as type BII, and intraspinal cysts arising from the spondylolytic cleft as type BIII. The movements were characterized by a radiologist and a neurosurgeon experienced in positional MRI. Clinical findings were correlated with the different types of instability. Results A high agreement was found between the two observers. In total, 131 segments were characterized as type A, six as type BI, 24 as type BII, and 10 as type BIII. In five segments, the type differed between the right and the left side. Two patients had a mixed type BI/II, another two patients had a mixed type BII/III, and one patient had a mixed type BI/III. Patients with type BII and BIII instabilities suffered more often from radicular symptoms compared to patients without any instability. Conclusion The presented classification might help to better understand and study changes encountered in the spondylolytic cleft in patients with spondylolysis and isthmic spondylolisthesis using positional MRI.

Pathomechanisms of discogenic low back pain in humans and animal models

BACKGROUND CONTEXT

Although explored in humans and animal models, the pathomechanisms of discogenic low back pain (LBP) remain unknown.

PURPOSE

The aim of this study was to review the literature about the pathomechanisms of discogenic LBP.

METHODS

Animal models of discogenic pain and specimens from degenerated human intervertebral discs (IVDs) have provided clues about the pathomechanisms of discogenic LBP. Painful discs are characterized by a confluence of innervation, inflammation, and mechanical hypermobility. These three possible mechanisms are discussed in this review.

RESULTS

Animal models and specimens from humans have revealed sensory innervation of lumbar IVDs and sensory nerve ingrowth into the inner layer of IVDs. Cytokines such as tumor necrosis factor-α and interleukins induce this ingrowth. Nerve growth factor has also been recently identified as an inducer of ingrowth. Finally, disc degeneration induces several collagenases; their action results in hypermobility and pain.

CONCLUSIONS

To treat discogenic LBP, it is important to prevent sensitization of sensory nerve fibers innervating the IVD, to suppress pathogenic increases of cytokines, and to decrease disc hypermobility.

Adjacent disc and facet joint degeneration in young adults with low-grade spondylolytic spondylolisthesis: A magnetic resonance imaging study

BACKGROUND/PURPOSE

Premature adjacent-level degeneration has been attributed to vertebral fusion, but spondylolisthesis has not been reported as a pathological factor responsible for the degeneration of adjacent disc and facet joint. We hypothesized that the degeneration of disc and facet joints in the adjacent levels is correlated with spondylolisthesis.

METHODS

Magnetic resonance images of 35 symptomatic young adults (16-29 years old) with low-grade L5-S1 spondylolytic spondylolisthesis (Meyerding Grade 1 or 2) and 50 symptomatic young referents (20-29 years old) with L5-S1 disc herniation without spondylolisthesis were recruited to compare the differences between disc and facet-joint degenerations at the olisthetic and adjacent levels using the Mantel extension test.

RESULTS

There were statistically significant degenerative changes of the discs and facet joints at the olisthetic and adjacent levels of patients with spondylolytic spondylolisthesis compared with the reference group. There is a trend that the disc and facet joints degenerate the most at the olisthetic level and become less affected at adjacent levels away from the lesion of pars defect.

CONCLUSION

Low-grade spondylolytic spondylolisthesis was associated with significant degenerations of the disc and facet joints at olisthetic and adjacent levels in young adults.

Spondylolysis and spondylolisthesis: prevalence of different forms of instability and clinical implications

STUDY DESIGN

Imaging study with an evaluation of incidences and clinical correlation.

OBJECTIVE

To evaluate the incidence of 3 different types of instabilities in patients with spondylolysis or isthmic spondylolisthesis. Clinical findings are correlated with imaging findings, and the imaging findings are analyzed with regard to their clinical implications.

SUMMARY OF BACKGROUND DATA

Spondylolysis and isthmic spondylolisthesis are common disorders. An unstable slip is the most well-known form of instability, but other forms also exist. However, the incidence of these instabilities and their clinical implications are yet unclear.

METHODS

A total of 140 patients with 141 levels of spondylolysis identified by MRI (magnetic resonance imaging) were included in this study. Using positional MRI, the instability of the slip, an increased angular movement, and movement in the spondylolytic cleft were assessed. On the basis of clinical findings, the patients were classified as presenting with either radicular or nonradicular symptoms. The incidence of the instabilities was recorded and correlated with the incidence of radicular symptoms.

RESULTS

Fifteen patients had an unstable slip (anterior instability); 35, an increased angular movement (angular instability); and 34 patients, a movement in the spondylolytic cleft (posterior instability). All forms of instability could be found together. No instability at all was found in 76 patients. Radicular symptoms were found significantly more often in patients with one or more of the described instabilities compared with patients without instability.

CONCLUSION

All 3 described forms of instability are common in spondylolysis or isthmic spondylolisthesis and associated with radicular pain. This finding stresses the value of positional MRI in the evaluation of patients with spondylolysis and isthmic spondylolisthesis, especially if radicular symptoms are present.

Chiropractic management of mechanical low back pain secondary to multiple-level lumbar spondylolysis with spondylolisthesis in a United States Marine Corps veteran: a case report

OBJECTIVE

This case report describes the evaluation and conservative management of mechanical low back pain secondary to multiple-level lumbar spondylolysis with spondylolisthesis in a United States Marine Corps veteran within a Veterans Affairs Medical Center chiropractic clinic.

CLINICAL FEATURES

The 43-year-old patient had a 20-year history of mechanical back pain secondary to an injury sustained during active military duty. He had intermittent radiation of numbness and tingling involving the right lower extremity distal to the knee. Radiographs of the lumbosacral region demonstrated a grade I spondylolisthesis of L3 in relation to L4 and a grade II spondylolisthesis of L4 in relation to L5 secondary to bilateral pars interarticularis defects. There was marked narrowing of the L4-5 disk space with associated subchondral sclerosis.

INTERVENTION AND OUTCOME

A course of conservative management consisting of 10 treatments including lumbar flexion/distraction and activity modification was provided over an 8-week period. Despite the long-standing nature of the complaint and underlying multiple-level lumbar spondylolysis with spondylolisthesis, there was a 25% reduction in low back pain severity on the numeric rating scale and a 22% reduction in perceived disability related to low back pain on the Revised Oswestry Disability Questionnaire.

CONCLUSIONS

Conservative management is considered to be the standard of care for spondylolysis and should be explored in its various forms for symptomatic low back pain patients who present without neurologic deficits and with spondylolisthesis below grade III. The response to treatment for the veteran patient in this case suggests that lumbar flexion/distraction may serve as a safe and effective component of conservative management of mechanical low back pain for some patients with spondylolysis and spondylolisthesis.

Prevalence of spondylolysis and its relationship with low back pain in selected population

Background

To determine the prevalence of spondylolysis in a selected population and evaluate the association of spondylolysis with low back pain (LBP). Spondylolysis is widespread in the general population but the prevalence of spondylolysis and its relationship with LBP in the Korean population is controversial.

Methods

A sample of 855 participants (age, 20 to 86 years) from our medical center who underwent multidetector computed tomography (CT) imaging to assess abdominal and urological lesions were enrolled in this study. The occurrence of LBP requiring medication in the preceding 12 months was evaluated using a self-report questionnaire (a modified Nordic Low Back Pain Questionnaire). The presence of spondylolysis was characterized by CT imaging. Multiple logistic regression models were used to examine the association between spondylolysis and LBP, while adjusting for gender and age.

Results

Seventy-eight study subjects (9%) demonstrated spondylolysis on CT imaging. There was no significant difference between the age groups (p = 0.177). The p-value of gender was 0.033 but this was not significant due to the selected population bias. Three hundred eleven study subjects (36%) had back pain. There was a significant difference between gender (p = 0.001). No significant association was identified between spondylolysis and the occurrence of LBP.

Conclusions

The prevalence of LBP was 36.37% and the prevalence of lumbar spondylolysis in a selected population, who visited hospital for abdominal or urological lesions except LBP, was 9.12% based on CT imaging. Males demonstrated a similar presence of LBP to females but a significantly higher incidence of spondylolysis (p = 0.033). The prevalence of spondylolysis was not associated with the presence of LBP and age in adulthood.

Spondylolysis and spondylolisthesis: prevalence and association with low back pain in the adult community-based population

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To determine prevalence rates of spondylolysis, isthmic, and degenerative spondylolisthesis in an unselected adult community-based population; and to evaluate the association of spondylolysis, isthmic, and degenerative spondylolisthesis with low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Spondylolysis and spondylolisthesis are prevalent in the general population; however, the relationship between these conditions and LBP is controversial.

METHODS

This study was an ancillary project to the Framingham Heart Study. A sample of 3529 participants of the Framingham Heart Study aged 40 to 80 years underwent multidetector CT imaging to assess aortic calcification. One hundred eighty-eight individuals were consecutively enrolled in this study to assess radiographic features potentially associated with LBP. The occurrence of LBP in the preceding 12 months was evaluated using a self-report questionnaire. The presence of spondylolysis and spondylolisthesis was characterized by CT imaging. We used multiple logistic regression models to examine the association between spondylolysis, spondylolisthesis, and LBP, while adjusting for gender, age, and BMI.

RESULTS

Twenty-one study subjects demonstrated spondylolysis on computed tomography (CT) imaging. The male-to-female ratio was approximately 3:1. Twenty-one percent of subjects with bilateral spondylolytic defects demonstrated no measurable spondylolisthesis. The male-to-female ratio of degenerative spondylolisthesis was 1:3, and the prevalence of degenerative spondylolisthesis increased from the fifth through 8 decades of life. Thirty-eight subjects (20.4%) reported significant LBP. No significant association was identified between spondylolysis, isthmic spondylolisthesis, or degenerative spondylolisthesis, and the occurrence of LBP.

CONCLUSION

Based on CT imaging of an unselected community-based population, the prevalence of lumbar spondylolysis is 11.5%, nearly twice the prevalence of previous plain radiograph-based studies. This study did not reveal a significant association between the observation of spondylolysis on CT and the occurrence of LBP, suggesting that the condition does not seem to represent a major cause of LBP in the general population.