Disc distraction shows evidence of regenerative potential in degenerated intervertebral discs as evaluated by protein expression, magnetic resonance imaging, and messenger ribonucleic acid expression analysis

Evolving Spinal Treatment Modalities: A Review of the Literature on Non-surgical Interferential Differential Dynamics (IDD) Therapy

Low back pain is one of the most common ailments encountered by physicians and orthopedic surgeons. There are various modalities used to treat low back pain, including conservative management, and a few of them involve rest, medications, massage, bracing, acupuncture, and physical therapy. Though most of the patients improve with conservative management, the burden of this disease has been very high and caused a significant amount of economic loss. Therefore, in-depth knowledge of all conservative methods is essential for physicians managing low back pain. Furthermore, there can be many causes of low back pain. Some of the more common ones are mechanical back pain due to paraspinal muscles or facetal in origin, discogenic back pain, and sacroiliac joint dysfunction. Many patients, especially the older population, have the discogenic origin as the more common cause of back pain, and traction therapy has been used for its treatment for ages. In this review, we discuss non-surgical spinal decompression/traction therapy popularly known as interferential differential dynamics (IDD) therapy with its current standing and recent advancement.

Lumbar disc rehydration after dynamic stabilization: A systematic review

BACKGROUND

Interbody fusion combined with posterior screw fixation is a traditional method used for treating lumbar degenerative disease (LDD). But in recent years, there have been more and more reports about its complications. Dynamic Stabilization Systems (DSS) are another method for the treatment of LDD, but the clinical results are still inconclusive. The objective of this study is to review, analyze, and discuss the probability of disc rehydration by DSS designed for LDD by systematically reviewing previous relevant studies.

METHODS

The Pubmed, Web of Science, and Embase databases were searched using keywords for articles published before June 2022. The following keywords were used: rehydration, rehydrated, lumbar, spine, disc, spinal, degenerative disc disease, degenerative spine disease, vertebrae, vertebral column, thoracolumbar, and lumbosacral. The included studies were printed in English. Two independent investigators compiled all data. For the quality assessment, the Newcastle-Ottawa Scale was used to evaluate case-control studies, while the Joanna Briggs Institute critical appraisal checklist was used to evaluate the case series studies.

RESULTS

This systematic review included 7 studies comprised of 5 case series and 2 case-control studies. Seven articles involving 199 cases were enrolled for the data extraction. Of the 199 cases, 55 cases observed rehydration, as evaluated by Pfrimann grading on magnetic resonance imaging. The rehydration rate was 27.6% (55/199). DSS can provide positive clinical outcomes. Both visual analog scale and Oswestry Dysfunctional Index scores were significantly improved at the final follow-up.

CONCLUSION

DSS may promote disc rehydration and delay the development of LDD to some extent. Mechanical stretch may play an important role in the progress of intervertebral disc rehydration. It provides important evidence for the clinical application of DSS.

Subjective assessment and biochemical evaluation of traction therapy in women with chronic low back pain: does body mass index matter? A clinical study

BACKGROUND

Apart from the positive effect of lumbar traction on structural changes within the spine in patients with low back pain, it is likely that therapeutic effects are correlated with pain biomarkers in the blood. Among them, systemic metabolic factors related to obesity may play an important role. This is the first study designed to examine the effectiveness of traction therapy in two experimental groups with considerably different BMI and to assess relationships between blood biomarkers and low back pain intensity.

METHODS

In the prospective clinical trial, women suffering from chronic low back pain were allocated into the normal-weight or obesity groups. Patients in both groups underwent twenty sessions of lumbar traction therapy (30 min a day, continuous mode with a force level of 25-30% of body weight). Before and after therapy subjective assessments of pain (VAS and PPT) were performed, and serum concentrations of aggrecan chondroitin sulfate 846 epitope (CS-846), neuropeptide Y, leptin, adipsin and growth and differentiation factor 15 (GDF-15) were determined. The data were statistically evaluated for 28 women.

RESULTS

After therapy, the maximal low back pain decreased in both groups, GDF-15 concentration was reduced in the normal-weight group and increased in the obesity group, and CS-846 concentration decreased in the obesity group. The sensation of PPT in the lumbar spine and mean concentrations of neuropeptide Y, leptin and adipsin did not change in both groups. However, the relationships of GDF-15, leptin, and adipsin concentrations with the perception of pain were revealed.

CONCLUSION

Distinct differences between the normal-weight and obesity groups pointed on the role of excessive adipose tissue in aggravating the inflammatory processes and in the development of low back pain. Adipsin, CS-846 and GDF-15 aspire to be the low back pain biomarkers in women with obesity, but there is a need for further research to answer whether they might be considered reliable biomarkers for the prognosis and monitoring of chronic low back treatment.

TRIAL REGISTRATION

NCT04507074, registered prospectively on July 6, 2020.

Regenerating and repairing degenerative intervertebral discs by regulating the micro/nano environment of degenerative bony endplates based on low-tension mechanics

Background

Conservative treatment is the recommended first-line treatment for degenerative disc diseases. Traction therapy has historically been one of the most common clinical methods to address this, but the clinical effect remains controversial.

Methods

Forty-two six-month-old male Sprague-Dawley rats were randomly divided into six groups: the model group (Group A, four coccyx vertebrae (Co7-Co10) were fixed with customized external fixators, and the vertebral disc degeneration model was constructed by axial compression of the target segment Co8 - Co9 for 4 weeks), the experimental control group (Group B, after successful modeling, the external fixation device was removed and self-rehabilitation was performed) and four intervention groups (Groups C to F): Groups C and E: Co8 - Co9 vertebrae compressed for 4 weeks followed by two or 4 weeks of high tension traction (HTT), respectively, and Groups D and F: vertebrae compressed for 4 weeks followed by two or 4 weeks of low-tension traction (LTT), respectively. Imaging tests (X-ray and MRI) were performed to assess disc height and T2 signal intensity at each time point. After the experiment, the animals were euthanized, and the caudal vertebrae were collected for analysis of intervertebral disc histopathology, proteoglycan content, and micronanostructure of the annulus fibrosus, nucleus pulposus and bony endplate.

Results

Signs of tissue regeneration were apparent in all four intervention groups. After two to 4 weeks of intervention (HTT and LTT), the morphology of pores in the bony endplate, their number, and diameter had recovered significantly compared with those in Group A. The LTT group was superior to the HTT group, and the 4w in situ group was significantly superior to the 2w group. Meanwhile, the histological scores of discs, the mean fibril diameter and modulus of annulus fibrosus were significantly improved compared with the control groups, and the LTT group was superior to HTT group.

Conclusions

Low-tension traction better promotes active reconstruction of bony endplates and improves the elastic modulus and micro/nanostructure of the disc. Thus, it further promotes the regeneration and repair of intervertebral discs.

Short-Term Effect of Lumbar Traction on Intervertebral Discs in Patients with Low Back Pain: Correlation between the T2 Value and ODI/VAS Score

OBJECTIVE

The effect of lumbar traction on low back pain (LBP) patients is controversial. Our study aims to assess changes in the intervertebral disc water content after lumbar traction using T2 mapping and explore the correlation between changes in the T2 value and Oswestry Disability Index (ODI)/visual analogue scale (VAS) score.

DESIGN

Lumbar spine magnetic resonance imaging was performed, and the ODI/VAS scores were recorded in all 48 patients. Midsagittal T2-weighted imaging and T2 mapping were performed to determine the Pfirrmann grade and T2 value. Then, the T2 values were compared between pre- and posttraction, and the correlation between changes in the T2 value and ODI/VAS scores were examined.

RESULTS

In the traction group, the changes in the nucleus pulposus (NP) T2 values for Pfirrmann grades II-IV and the annulus fibrosus (AF) T2 values for Pfirrmann grade II were statistically significant after traction (P < 0.05). Changes in the mean NP T2 value of 5 discs in each patient and in the ODI/VAS score showed a strong correlation (r = 0.822, r = 0.793).

CONCLUSION

T2 mapping can be used to evaluate changes in the intervertebral disc water content. Ten sessions of traction resulted in a significant increase in quantitative T2 measurements of the NP in discs for Pfirrmann grade II-IV degeneration and remission of the patients' clinical symptoms in the following 6 months. Changes in the mean NP T2 value of 5 discs in each patient were strongly correlated with changes in the ODI/VAS score.

Mechanical Changes of the Lumbar Intervertebral Space and Lordotic Angle Caused by Posterior-to-Anterior Traction Using a Spinal Thermal Massage Device in Healthy People

Background: The axial (horizontal) traction approach has been traditionally used for treatment of low back pain-related spinal disorders such as nuclear protrusion, primary posterolateral root pain, and lower thoracic disc herniation; however, it is known to have some technical limitations due to reductions of the spinal curve. Lumbar lordosis plays a pivotal function in maintaining sagittal balance. Recently, vertical traction and combination traction have been attracting attention due to improving therapeutic outcomes, although evidence of their clinical application is rare; therefore, this study was conducted to investigate the mechanical changes of lumbar intervertebral space, lordotic angle, and the central spinal canal area through vertical traction treatment using a spinal massage device in healthy participants. Methods: In total, 10 healthy subjects with no musculoskeletal disorders and no physical activity restrictions participated. The participants lay on the experimental device (CGM MB-1901) in supine extended posture and vertical traction force was applied in a posterior-to-anterior direction on the L3–4 and L4–5 lumbar sections at level 1 (baseline) and level 9 (traction mode). Magnetic resonance (MR) images were recorded directly under traction mode using the MRI scanner. The height values of the intervertebral space (anterior, center, and posterior parts) and lordosis angle of the L3–4 and L4–5 sections were measured using Image J software and the central spinal canal area (L4–5) was observed through superimposition method using the MR images. All measurement and image analyses were conducted by 2 experienced radiologists under a single-blinded method. Results: The average height values of the intervertebral space under traction mode were significantly increased in both L3–4 and L4–5 sections compared to baseline, particularly in the anterior and central parts but not in the posterior part. Cobb’s angle also showed significant increases in both L3–4 and L4–5 sections compared to baseline (p < 0.001). The central spinal canal area showed a slightly expanded feature in traction mode. Conclusions: In this pilot experiment, posterior-to-anterior vertical traction on L3–4 and L4–5 sections using a spinal massage device caused positive and significant changes based on increases of the intervertebral space height, lumbar lordosis angle, and central spinal canal area compared to the baseline condition. Our results are expected to be useful as underlying data for the clinical application of vertical traction.

Effects of Axial Compression and Distraction on Vascular Bud and VEGFA Expression in the Vertebral Endplate of an Ex Vivo Rabbit Spinal Motion Segment Culture Model

STUDY DESIGN

An ex vivo study of the rabbit's vertebral endplate.

OBJECTIVE

The aim of this study was to assess the effect of axial compression and distraction on vascular buds and vascular endothelial growth factor (VEGFA) expression of the vertebral endplate (VEP).

SUMMARY OF BACKGROUND DATA

The abnormal load can lead to intervertebral disc degeneration (IDD), whereas axial distraction can delay this process. The effects of different mechanical loads on the intervertebral disc (IVD) have been hypothesized to be related to changes in the vascular buds of the VEP; moreover, the process that might involve the vascular endothelial growth factor (VEGF) within the VEP.

METHODS

Rabbit spinal segments (n = 40) were harvested and randomly classified into four groups: Control group, no stress was applied; Group A, a constant compressive load applied; Group B, compression load removed for a fixed time daily on a continuous basis, and substituted with a distraction load for 30 minutes; and Group C, compression removed for 30 minutes for a fixed period daily on a continuous basis. Tissue specimens were collected before the culture (day 0) and on day 14 post-culture of each group for analysis of IVDs' morphology, and protein and mRNA expression of Aggrecan, COL2al, VEGFA, and vascular endothelial growth factor receptor 2 of the VEPs.

RESULTS

Application of axial distraction and dynamic load compression significantly delayed time- and constant compression-mediated VEP changes and IDD. Moreover, the degree of degeneration was associated with loss of vascular buds, as well as the downregulation of VEGFA and its receptor.

CONCLUSION

The regulation of vascular buds and VEGF expression in the VEP represents one of the mechanisms of axial distraction and dynamic loading.Level of Evidence: N/A.

Intervertebral disc degeneration and regeneration: a motion segment perspective

Back and neck pain have become primary reasons for disability and healthcare spending globally. While the causes of back pain are multifactorial, intervertebral disc degeneration is frequently cited as a primary source of pain. The annulus fibrosus (AF) and nucleus pulposus (NP) subcomponents of the disc are common targets for regenerative therapeutics. However, disc degeneration is also associated with degenerative changes to adjacent spinal tissues, and successful regenerative therapies will likely need to consider and address the pathology of adjacent spinal structures beyond solely the disc subcomponents. This review summarises the current state of knowledge in the field regarding associations between back pain, disc degeneration, and degeneration of the cartilaginous and bony endplates, the AF-vertebral body interface, the facet joints and spinal muscles, in addition to a discussion of regenerative strategies for treating pain and degeneration from a whole motion segment perspective.

Low energy extracorporeal shock wave therapy combined with low tension traction can better reshape the microenvironment in degenerated intervertebral disc regeneration and repair

BACKGROUND

Low-tension traction is more effective than high-tension traction in restoring the height and rehydration of a degenerated disc and to some extent the bony endplate. This might better reshape the microenvironment for disc regeneration and repair. However, the repair of the combination of endplate sclerosis, osteophyte formation, and even collapse leading to partial or nearly complete occlusion of the nutrient channel is greatly limited.

PURPOSE

To evaluate the effectiveness of low-intensity extracorporeal shock wave therapy (ESWT) combined with low tension traction for regeneration and repair of moderately and severely degenerated discs; to explore the possible mechanism of action.

STUDY DESIGN

Animal study of a rat model of degenerated discs.

METHODS

A total of thirty-five 6-month old male Sprague-Dawley rats were randomly assigned to one of five groups (n=7, each group). In Group A (model group), caudal vertebrae were immobilized using a custom-made external device to fix four caudal vertebrae (Co7-Co10) whereas Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration. In Group B (experimental control group), as in Group A, disc degeneration was successfully induced after which the fixed device was removed for 8 weeks of self-recovery. The remaining three groups of rats represented the intervention Groups (C-E): after successful generation of disc degeneration in Group C (com - 4w/tra - 4w) and Group D (com - 4w/ESWT), as described for group A, low-tension traction (in-situ traction) or low-energy ESWT was administered for 4 weeks (ESWT parameters: intensity: 0.15 Mpa; frequency: 1 Hz; impact: 1,000 each time; once/week, 4 times in total); Group E (com - 4w/tra - 4w/ESWT): disc degeneration as described for group A, low-tension traction combined with low-energy ESWT was conducted (ESWT parameters as Group D). After experimentation, caudal vertebrae were harvested and disc height, T2 signal intensity, disc morphology, total glycosaminoglycan (GAG) content, gene expression, structure of the Co8-Co9 bony endplates and elastic moduli of the discs were measured.

RESULTS

After continuous low-tension traction, low energy ESWT intervention or combined intervention, the degenerated discs effectively recovered their height and became rehydrated. However, the response in Group D was weaker than in the other intervention groups in terms of restoration of intervertebral disc (IVD) height, whereas Group E was superior in disc rehydration. Tissue regeneration was evident in Groups C to E using different interventions. No apparent tissue regeneration was observed in the experimental control group (Group B). The histological scores of the three intervention groups (Groups C-E) were lower than those of Groups A or B (p<.0001), and the scores of Groups C and E were significantly lower than those of Group D (p<.05), but not Group C versus Group E (p>.05). Compared with the intervention groups (Groups C-E), total GAG content of the nucleus pulposus (NP) in Group B did not increase significantly (p>.05). There was also no significant difference in the total GAG content between Groups A and B (p>.05). Of the three intervention groups, the recovery of NP GAG content was greatest in Group E. The expression of collagen I and II, and aggrecan in the annulus fibrosus (AF) was up-regulated (p<.05), whereas the expression of MMP-3, MMP-13, and ADAMTS-4 was down-regulated (p<.05). Of the groups, Group E displayed the greatest degree of regulation. The trend in regulation of gene expression in the NP was essentially consistent with that of the AF, of which Group E was the greatest. In the intervention groups (Groups C-E), compared with Group A, the pore structure of the bony endplate displayed clear changes. The number of pores in the endplate in Groups C to E was significantly higher than in Group A (p<.0001), among which Group C versus Group D (p=.9724), and Group C versus Group E (p=.0116). There was no significant difference between Groups A and B (p=.5261). In addition, the pore diameter also increased, the trend essentially the same as that of pore density. There was no significant difference between the three intervention groups (p=.7213). It is worth noting that, compared with Groups A and B, peripheral pore density and size in Groups D and E of the three intervention groups recovered significantly. The elastic modulus and diameter of collagen fibers in the AF and NP varied with the type of intervention. Low tension traction combined with ESWT resulted in the greatest impact on the diameter and modulus of collagen fibers.

CONCLUSIONS

Low energy ESWT combined with low tension traction provided a more stable intervertebral environment for the regeneration and repair of moderate and severe degenerative discs. Low energy ESWT promoted the regeneration of disc matrix by reducing MMP-3, MMP-13, and ADAMTS-4 resulting in inhibition of collagen degradation. Although axial traction promoted the recovery of height and rehydration of the IVD, combined with low energy ESWT, the micro-nano structure of the bony endplate underwent positive reconstruction, tension in the annulus of the AF and nuclear stress of the NP declined, and the biomechanical microenvironment required for IVD regeneration and repair was reshaped.

Stable mechanical environments created by a low-tension traction device is beneficial for the regeneration and repair of degenerated intervertebral discs

BACKGROUND

By blocking the cascade of reactions leading to intervertebral disc degeneration through immobilization-traction, a delay in intervertebral disc degeneration and its regeneration, to some extent, has been observed. However, the precise balance of regulation of the microenvironment of intervertebral disc biomechanics and coordination of the complex spatiotemporal reconstruction of the extracellular matrix have not yet been solved, and clinical results are far from successful.

PURPOSE

In the present study, a mechanical degeneration model was constructed to evaluate the possibility and effectiveness of disc regeneration or repair through low-tension traction of degenerated discs so as to provide basic biomechanical information for clinical optimization of the traction device and to establish traction parameters for prevention and treatment of disc degeneration.

STUDY DESIGN

A macro-, micro-, and nano-level structural analysis of degenerative discs of rat tail before and after controlled traction.

METHODS

Six-month-old male Sprague-Dawley rats were randomly divided into seven groups: Group A: control group (instrumented with Kirschner [K]-wires only); Group B: Model group (caudal vertebrae immobilized using a custom-made external device to fix four caudal vertebrae [Co7-Co10], while Co8-Co9 vertebrae underwent 4 weeks of compression to induce disc degeneration); Group C: experimental control group (devices removed after the 4 week compression described in Group B, and recovered by themselves for 4 weeks). The remaining four groups represented intervention groups (Groups D and F: Co8-Co9 vertebrae compressed for 4 weeks followed by 2 or 4 weeks of in situ traction, respectively; Groups E and G: vertebrae compressed for 4 weeks followed by 2 or 4 weeks of excessive traction, respectively). X-ray and magnetic resonance imaging were performed at each time point to measure disc height and T2 signal intensity. At the end of the experiment, the animals were euthanized and tail vertebrae harvested for analysis of intervertebral disc histopathology, proteoglycan content, elastic modulus of fibers of the annulus fibrosus (AF) and nucleus pulposus (NP), and microstructure of the bony end plate.

RESULTS

After 2 to 4 weeks of continuous traction (in situ and excessive traction), the Co8-Co9 intervertebral disc space of rats in Groups D to G increased significantly compared with Groups B and C (p < .05). In addition, signs of tissue regeneration were apparent in all four intervention groups (D-G). In addition, histologic scores of the intervention groups (D-G) were significantly lower than those in the model and experimental control groups (Groups B and C, respectively), although no significant difference was found between those four groups. Compared with the model group (Group B), total proteoglycan content of the NP in the intervention groups (D-G) increased significantly (p < .05). After 2 to 4 weeks of intervention (in situ and excessive traction), the morphology of pores in the bony end plate, their number, and the diameter had recovered significantly compared with those in Group B. The in situ traction group was superior to the excessive traction group, and 4 weeks in situ group significantly superior to the 2 weeks group. In all intervention groups, in both the inner and outer AF, mean fibril diameter decreased significantly (p < .05), although they remained larger in the excessive traction group than that in the in situ traction group. Consistent with trend in collagen fiber diameter, the outer AF was stiffer than the inner, and the modulus of the AF in each intervention group not significantly different from that of the control group (Group A) except Group C. However, within the NP, the variation in trend in diameter and modulus of collagen fibers was essentially inconsistent with that of the AF.

CONCLUSIONS

Degenerated discs exhibit greater reconstruction after low tension traction. It is clear that the intervertebral disc mechanical microenvironment depends to a greater extent on low-tension traction than high-tension traction.

The degenerative lumbar disc: not a disease, but still an important consideration for OMPT practice: a review of the history and science of discogenic instability

BACKGROUND

A recent AAOMPT position paper was published that opposed the use of the term 'degenerative disc disease' (DDD), in large part because it appears to be a common age-related finding. While common, there are significant physiologic and biomechanical changes that occur as a result of discogenic degeneration, which are relevant to consider during the practice of manual therapy.

METHODS

A narrative review provides an overview of these considerations, including a historical perspective of discogenic instability, the role of the disc as a pain generator, the basic science of a combined biomechanical and physiologic cycle of degeneration and subsequent discogenic instability, the influence of rotation on the degenerative segment, the implications of these factors for manual therapy practice, and a perspective on an evidence-based treatment approach to patients with concurrent low back pain and discogenic degeneration.

CONCLUSIONS

As we consider the role of imaging findings such as DDD, we pose the following question: Do our manual interventions reflect the scientifically proven biomechanical aspects of DDD, or have we chosen to ignore the helpful science as we discard the harmful diagnostic label?

Constant compression decreases vascular bud and VEGFA expression in a rabbit vertebral endplate ex vivo culture model

SUMMARY OF BACKGROUND DATA

The vascular buds in the vertebral endplate (VEP) are the structural foundation of nutrient exchange in the intervertebral disc (IVD). VEGF is closely related to angiogenesis in the endplate and intervertebral disc degeneration (IDD).

OBJECTIVE

To investigate the effects of static load on vascular buds and VEGF expression in the VEP and to further clarify the relation between IDD and VEGF.

METHODS

IVD motion segments were harvested from rabbit lumbar spines and cultured under no-loading conditions (controls) or in custom-made apparatuses under a constant compressive load (0.5 MPa) for up to 14 days. Tissue integrity and the number of vascular buds were determined, and the concentrations and expression of Aggrecan, COL2a1, and VEGFA in the VEPs were assessed after 3, 7, and 14 days of culturing and then compared with those of fresh tissues.

RESULTS

Under the constant compression, the morphological integrity of the VEPs was gradually disrupted, and immunohistochemistry results showed a significant decrease in the levels of Agg and COL2a1. During the static load, the number of vascular buds in the VEPs was gradually reduced from the early stage of culture, and ELISA showed that the constant compressive load caused a significant decrease in the VEGFA and VEGFR2 protein concentrations, which were consistent with the immunohistochemistry results. Western blot and RT-PCR results also showed that the loading state caused a significant decrease in VEGFA expression compared with that of fresh and control samples.

CONCLUSIONS

Constant compression caused degeneration of the VEP as well as a decreased number of vascular buds, thereby accelerating disc degeneration. VEGFA is involved in this process. We anticipate that regulating the expression of VEGFA may improve the condition of the lesions to the vascular buds in the endplates, thus enhancing the nutritional supply function in IVD and providing new therapeutic targets and strategies for the effective prevention and treatment of IDD.

Lumbar disc rehydration in the bridged segment using the BioFlex dynamic stabilization system: A case report and literature review

BACKGROUND

In recent years, the mechanical concept of intervertebral disc regeneration has become more and more popular due to the increasing awareness of the importance of preservation of spine movement. Interestingly, there is increasing evidence, however, that dynamic stabilization systems may compensate non-physiological loads, limit pathological movement, normalize disc height and intradiscal pressure, and provide an adaptive environment for disc regeneration.

CASE SUMMARY

The patient was a 54-year-old man, who presented with a 10-year history of mechanical back pain, which had become progressively serious and radiated into the left lower limb with numbness 3 mo prior. He had decreased muscle strength (class IV) of the left dorsal extensor and plantar flexor. Magnetic resonance imaging scans showed L3-S1 disc degeneration and L4-L5 disc herniation. Because the patient did not respond to various conservative treatments, he underwent a posterior L4-5 discectomy with fixation of the BioFlex dynamic stabilization system (Bio-Spine, Seoul, Korea). Preoperative symptoms were relieved and lumbar function was markedly improved after the operation. L4-L5 disc rehydration of instrumented segment was noted on magnetic resonance imaging at the 2-year follow-up.

CONCLUSION

Rehydration of the degenerated disc in our patient indicates that the BioFlex dynamic stabilization system may promote disc regeneration. Further research is needed to provide more evidence to support lumbar disc rehydration in the bridged segment using this system.

The effect of mechanical traction on low back pain in patients with herniated intervertebral disks: a systemic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of traction in improving low back pain, functional outcome, and disk morphology in patients with herniated intervertebral disks.

DATA SOURCE

PubMed, Scopus, Embase, and the Cochrane Library were searched from the earliest record to July 2019.

REVIEW METHODS

We included randomized control trials which (1) involved adult patients with low back pain associated with herniated disk confirmed by magnetic resonance imaging or computed tomography, (2) compared lumbar traction to sham or no traction, and (3) provided quantitative measurements of pain and function before and after intervention. Methodological quality was assessed using the physiotherapy evidence database (PEDro) scale and Cochrane risk of bias assessment.

RESULTS

Initial searches for literature yielded 3015 non-duplicated records. After exclusion based on the title, abstract, and full-text review, 7 articles involving 403 participants were included for quantitative analysis. Compared with the control group, the participants in the traction group showed significantly greater improvements in pain and function in the short term, with standard mean differences of 0.44 (95% confidence interval (CI): 0.11-0.77) and 0.42 (95% CI: 0.08-0.76), respectively. The standard mean differences were not significant to support the long-term effects on pain and function, nor the effects on herniated disk size.

CONCLUSION

Compared with sham or no traction, lumbar traction exhibited significantly more pain reduction and functional improvements in the short term, but not in the long term. There is insufficient evidence to support the effect of lumbar traction on herniated disk size reduction.

Toward a cure for lumbar spinal stenosis: The potential of interspinous process decompression

There is a growing impetus to treat aging as a disease in the quest to significantly extend the human life span through cellular regeneration methods. This approach, while promising, overlooks the fact that the evolutionary adaptation to bipedalism puts the human body in a distinctively vulnerable biomechanical and functional position. Orthograde human posture places unusually-high axial compressive loads on the weight-bearing joints of the skeleton, resulting in arthritic deterioration with aging. The effects are particularly robust in the lumbar spine were age-related degeneration, most commonly lumbar spinal stenosis (LSS), is ubiquitous among the elderly. It is postulated that re-establishing a favorable mechanical environment via interventions that unload the affected spinal joint complex may mitigate and potentially reverse the structural damage that is the cardinal pathoanatomical feature of this disease. The hypothesis of this paper is that a minimally-invasive surgical procedure, interspinous process decompression (IPD), which utilizes a stand-alone intervertebral spacer, effectively unloads the diseased spinal motion segment providing a healthy micro-environment to reverse and repair age-related and genetic deterioration of the spinal motion segment. Several lines of supporting evidence are provided from long-term follow-up results of a randomized controlled trial of IPD safety and effectiveness of the Superion® device including clinical outcomes, reoperation rates, opioid analgesic usage and advanced imaging utilization. All of these outcomes show uniquely-favorable trends with time that imply that the benefits of IPD are structural. The compendium of evidence suggests that IPD offers both a durable palliative effect due to direct blocking of back extension and a disease-modifying effect due to unloading of the spinal joint complex.

Controlled immobilization-traction based on intervertebral stability is conducive to the regeneration or repair of the degenerative disc: an in vivo study on the rat coccygeal model

BACKGROUND CONTEXT

Previous studies have shown the potential for intervertebral disc tissue regeneration is very limited. While in vivo and in vitro studies have shown that traction can restore disc height and internal pressure, in many clinical studies it was shown that axial mechanical traction for the treatment of low back pain is ineffective.

PURPOSE

The aim of this study was to identify how the disc could be distracted, how to define the state of traction, and to further examine the feasibility of regenerating or restoring the degenerative disc by means of traction.

STUDY DESIGN

A macro- and microlevel structural analysis of degenerative discs of rat tail before and after controlled immobilization-traction.

METHODS

In this study, 49 6-month-old male Sprague-Dawley rats were randomly assigned to one of seven groups. Group A was the sham control group in which caudal vertebrae were instrumented with K-wires only. In Group B (model group), caudal vertebrae were immobilized using a custom-made external device to fix four caudal vertebrae (Co7-Co10) and Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration. In Group C, vertebrae Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration, followed by removal of the external apparatus. Rats in the other four groups (Groups D-G), Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration followed by 2 weeks, 4 weeks, 6 weeks, and 8 weeks of distraction, respectively. Caudal vertebrae were harvested and disc height, T2 signal intensity of the discs, disc morphology, total glycosaminoglycan content of the nucleus pulposus and the structure of the Co8-Co9 end plate were evaluated.

RESULTS

After 4 weeks of compression, the intervertebral height and T2 signal intensity of Co8-Co9 vertebrae of rats in Groups B to G were significantly reduced compared with Group A (sham group, all p<.0001). Histological scores of rats in Group B averaged 10.14 and the total glycosaminoglycan (GAG) of nucleus pulposus averaged 238.21μg GAG/ng DNA. The bony end plate structure showed significant changes in comparison with the control Group. After 2 weeks to 8 weeks of traction, the disc space and T2 signal intensity of Co8-Co9 vertebrae in Group E were significantly recovered compared to that of rats in Group B (p<.0001), and the intervertebral height of the Co8-Co9 in Group D, Group F, and Group G when compared with Group B (p<.0001). Meanwhile, the T2 signal intensity of Co8-Co9 in Group D, F, and G when compared with Group B (p<.001). Histological scores dropped from an average of 10.14 in Group B to 5.57 in Group E, and 5.86 in Group F (all p<.0001). Furthermore, the total GAG content of the nucleus pulposus increased from an average of 238.21μg GAG/ng DNA in Group B to 601.02μg GAG/ng DNA in Group E (p<.0001). The number of pores of end plates in rats in Groups D and E both were significantly increased when compared to that of rats in Group B (Groups D vs Groups B, p<.05; Groups E vs Groups B, p<.0001).

CONCLUSIONS

A mechanical degenerative model was successfully established by using a custom-made device. We demonstrated that disc degeneration is a cascade of biochemical, mechanical, and structural changes mediated by cells in an abnormal mechanical environment. Not all levels of disc degeneration can be regenerated or repaired. Regeneration or recovery of disc degeneration requires specific conditions. Based on the immobilization-traction mode, the cascade cycle of disc degeneration is interrupted. Traction of 2 to 6 weeks is a sensitive period for regeneration of the degenerative disc. Moreover, the duration and extent of the traction loading must be moderately controllable, and beyond the limits that can lead to significant degeneration. These data may help improve our understanding of the pathogenesis of clinical disc degeneration and how to optimize the use of traction devices for possible regeneration.

Resorbable plating system stabilizes tissue-engineered intervertebral discs implanted ex vivo in canine cervical spines

Total disc replacement using tissue-engineered intervertebral discs (TE-IVDs) may offer a biological alternative to treat radiculopathy caused by disc degeneration. A composite TE-IVD was previously developed and evaluated in rat tail and beagle cervical spine models in vivo. Although cell viability and tissue integration into host tissue were promising, significant implant displacement occurred at multiple spinal levels. The goal of the present study was to assess the effects of a resorbable plating system on the stiffness of motion segments and stability of tissue-engineered implants subjected to axial compression. Canine motion segments from levels C2/C3 to C5/C6 were assessed as intact (CTRL), after discectomy (Dx), with an implanted TE-IVD only (PLATE-), and with a TE-IVD combined with an attached resorbable plate (PLATE+). Segments under PLATE+ conditions fully restored separation between endplates and showed significantly higher compressive stiffness than segments under PLATE- conditions. Plated segments partially restored more than 25% of the CTRL motion segment stiffness. Plate attachment also prevented implant extrusion from the disc space at 50% compressive strain, and this effect was more significant in segments from levels C3/C4 when compared to segments from level C5/C6. These results suggest that stabilization of motion segments via resorbable plating assists TE-IVD retention in the disc space while allowing the opportunity for implants to fully integrate into the host tissue and achieve optimal restoration of spine biomechanics.

Increased spinal height using propped slouched sitting postures: Innovative ways to rehydrate intervertebral discs

BACKGROUND

Upright and slouched sitting are frequently adopted postures associated with increased intradiscal pressure, spinal height loss and intervertebral disc pathology.

OBJECTIVES

To examine the effects of two sustained propped slouched sitting (PSS) postures on spinal height after a period of trunk loading.

METHODS

Thirty-four participants without a history of low back pain (LBP) were recruited (age 24.4 ± 1.6 years). Subjects sat in (1) PSS without lumbar support and (2) PSS with lumbar support for 10 min, after a period of trunk loading. Spinal height was measured using a stadiometer.

RESULTS

Mean spinal height increase during PSS without lumbar support was 2.94 ± 3.63 mm and with lumbar support 4.74 ± 3.07 mm.

CONCLUSIONS

Both PSS with and without lumbar support significantly increased spinal height after a period of trunk loading (p < 0.001). Such PSS postures can provide a valuable alternative to upright sitting and may be recommended for recovering spinal height in the working environment following periods of loading.

Total disc replacement using tissue-engineered intervertebral discs in the canine cervical spine

The most common reason that adults in the United States see their physician is lower back or neck pain secondary to degenerative disc disease. To date, approaches to treat degenerative disc disease are confined to purely mechanical devices designed to either eliminate or enable flexibility of the diseased motion segment. Tissue engineered intervertebral discs (TE-IVDs) have been proposed as an alternative approach and have shown promise in replacing native IVD in the rodent tail spine. Here we demonstrate the efficacy of our TE-IVDs in the canine cervical spine. TE-IVD components were constructed using adult canine annulus fibrosis and nucleus pulposus cells seeded into collagen and alginate hydrogels, respectively. Seeded gels were formed into a single disc unit using molds designed from the geometry of the canine spine. Skeletally mature beagles underwent discectomy with whole IVD resection at levels between C3/4 and C6/7, and were then divided into two groups that received only discectomy or discectomy followed by implantation of TE-IVD. Stably implanted TE-IVDs demonstrated significant retention of disc height and physiological hydration compared to discectomy control. Both 4-week and 16-week histological assessments demonstrated chondrocytic cells surrounded by proteoglycan-rich matrices in the NP and by fibrocartilaginous matrices in the AF portions of implanted TE-IVDs. Integration into host tissue was confirmed over 16 weeks without any signs of immune reaction. Despite the significant biomechanical demands of the beagle cervical spine, our stably implanted TE-IVDs maintained their position, structure and hydration as well as disc height over 16 weeks in vivo.

Age-related differences in the response of the L5-S1 intervertebral disc to spinal traction

BACKGROUND

Lumbar traction is a common treatment for low back pain; however its mechanisms of action are poorly understood. It has been hypothesized that a key effect of lumbar traction is its capacity to influence fluid movement within the intervertebral disc (IVD).

OBJECTIVES

To determine differences in the apparent diffusion coefficient (ADC) obtained with lumbar diffusion-weighted imaging (DWI) of the L5-S1 IVD before, and during, the application of lumbar traction.

DESIGN

Case series, repeated measures.

METHODS

A static traction load of ∼50% of body-weight was applied to the low back using a novel "MRI-safe" apparatus. DWI of the lumbar spine was performed prior to, and during the application of the traction load.

RESULTS

Participants were currently asymptomatic and included a young adult group (n = 18) and a middle-aged group (n = 15). The young adult group had a non-significant 2.2% increase in ADC (mean change = 0.03 × 10^-3 mm²/s, SD = 0.24, 95% CI = -0.09, 0.15). The ADC for the middle-aged group significantly increased by 20% (mean change of 0.18 × 10^-3 mm²/s, SD = 0.19; 95% CI = 0.07, 0.28; p = 0.003; effect size = 0.95). There was an inverse relationship between the ADC obtained before traction and the percent increase in ADC that was measured during traction.

CONCLUSION

Static traction was associated with an increase in diffusion of water within the L5-S1 IVDs of middle-age individuals, but not in young adults, suggesting age-related differences in the diffusion response. Further study is needed to assess the relationship between these findings and the symptoms of back pain.

LEVEL OF EVIDENCE

4.

Disc Rehydration after Dynamic Stabilization: A Report of 59 Cases

Study Design

A retrospective study investigating decrease in the nucleus pulposus signal intensity or disc height on magnetic resonance imaging (MRI) and disc degeneration.

Purpose

Although a degenerated disc cannot self-regenerate, distraction or stabilization may provide suitable conditions for rehydration and possible regeneration. This study aimed to evaluate clinical outcomes and disc regeneration via MRI in a series of patients with degenerative disc disease (DDD) who underwent lumbar stabilization with a dynamic stabilization system (DSS).

Overview of Literature

A dynamic system provides rehydration during early DDD.

Methods

Fifty-nine patients (mean age, 46.5 years) who undedwent stabilization with DSS for segmental instability (painful black disc) between 2004 and 2014 were retrospectively evaluated. All patients underwent MRI preoperatively and 12 months postoperatively. Intervertebral disc (IVD) degeneration grades at the implanted segment were categorized using the Pfirrmann classification system. Patients were followed for a mean of 6.4 years, and clinical outcomes were based on visual analog scale (VAS) and Oswestry disability index (ODI) scores.

Results

Significant improvements in back pain VAS and ODI scores from before surgery (7 and 68%, respectively) were reported at 6 (2.85 and 27.4%, respectively) and 12 months postoperatively (1.8 and 16.3%, respectively). Postoperative IVD changes were observed in 28 patients. Improvement was observed in 20 patients (34%), whereas progressive degeneration was observed in eight patients (13.5%). Thirty-one patients (52.5%) exhibited neither improvement nor progression. Single Pfirrmann grade improvements were observed in 29% of the patients and two-grade improvements were observed in 5%.

Conclusions

Our observations support the theory that physiological movement and a balanced load distribution are necessary for disc regeneration. We conclude that DSS may decelerate the degeneration process and appears to facilitate regeneration.

Mechanical effects of traction on lumbar intervertebral discs: A magnetic resonance imaging study

BACKGROUND

Although traction has long been used for treating patients with low back pain (LBP), its effects are still inconclusive mainly because of limited high-quality evidence.

OBJECTIVE

To provide evidence of the mechanism of traction on lumbar intervertebral discs.

DESIGN

A quantitative approach with a repeated measurement protocol.

METHOD

Nine participants (mean age = 22.1 ± 0.8 years) without any LBP history were recruited. Magnetic Resonance Images of the lumbar spine of each participant were recorded before and after 30 min of horizontal lying and directly after 30 min of horizontal traction of 42% body weight. The average, anterior, central, and posterior disc height and tilt angle of each lumbar disc and lumbar lordosis were measured.

RESULTS

A significant increase in the average disc height for all lumbar discs, a significant reduction of lumbar lordosis and changes in tilt angle were observed after the application of 30 min of resting followed by 30 min of traction. A significant increase in the average disc height was observed only in lower lumbar discs after 30 min of traction. The increase in the posterior disc height was more apparent than that in the anterior disc height.

CONCLUSIONS

Horizontal traction was evidently effective in increasing the disc height of lower lumbar levels, particularly in the posterior regions of the discs. Further evidence of the effects of traction of different modes, magnitudes, and durations on the change in disc height is required for proper control of traction applied to specific disc levels.

Effect of spinal decompression on the lumbar muscle activity and disk height in patients with herniated intervertebral disk

[Purpose] This study was conducted to clarify the difference in therapeutic effects between traction and decompression therapies, and their clinical therapeutic significance. [Subjects and Methods] The subjects were 31 patients aged 35 to 50 years who had unilateral or bilateral lumbar and radicular leg pain. An intervention program was implemented in 31 patients with lumbar herniated intervertebral disks. For the experimental group, 15 subjects were randomly selected to receive decompression therapy and trunk stabilization exercise. For the control group, 16 subjects were randomly selected to receive traction therapy and trunk stabilization exercise. [Results] Activities of the rectus abdominis, transverse abdominis, and external oblique muscles increased significantly in both groups. However, the activity of the erector spine muscle decreased, which was the only significant change in muscle activity among those of the other muscles in both groups. The disk herniation index in the experimental group decreased significantly in comparison with that in the control group, and the difference in the change in disk herniation index between the groups was significant. [Conclusion] Decompression therapy was demonstrated to be more effective clinically than conventional traction therapy as an intervention method for disk disease.

Interspinous process spacers versus traditional decompression for lumbar spinal stenosis: systematic review and meta-analysis

BACKGROUND

Interspinous spacers are used in selected patients for the treatment of lumbar spinal stenosis. The uses of interspinous devices are still debated, with reports of significantly higher reoperation rates and unfavourable cost-effectiveness compared to traditional decompression techniques.

METHODS

Six electronic databases were searched from their date of inception to December 2015. Relevant studies were identified using specific eligibility criteria and data was extracted and analyzed based on predefined primary and secondary endpoints.

RESULTS

Eleven comparative studies were obtained for qualitative and quantitative assessment, data extraction and analysis. There was no significant difference in VAS back pain, leg pain or ODI scores for standalone interspinous process device (IPD) vs. bony decompression. However, standalone IPD was associated with lower surgical complications (4% vs. 8.7%, P=0.03) but higher long-term reoperation rates (23.7% vs. 8.5%, P<0.00001). IPD as an adjunct to decompression had comparable patient-reported scores, complications and reoperation rates to decompression alone.

CONCLUSIONS

Current evidence indicates no superiority for mid- to long-term patient-reported outcomes for IPD compared with traditional bony decompression, with lesser surgical complications but at the risk of significantly higher reoperation rates and costs.

Biological Treatment Approaches for Degenerative Disk Disease: A Literature Review of In Vivo Animal and Clinical Data

STUDY DESIGN

Literature review.

OBJECTIVE

Degenerative disk disease (DDD) has a negative impact on quality of life and is a major cause of morbidity worldwide. There has been a growing interest in the biological repair of DDD by both researchers and clinicians alike. To generate an overview of the recent progress in reparative strategies for the treatment of DDD highlighting their promises and limitations, a comprehensive review of the current literature was performed elucidating data from in vivo animal and clinical studies.

METHODS

Articles and abstracts available in electronic databases of PubMed, Web of Science, and Google Scholar as of December 2014 were reviewed. Additionally, data from unpublished, ongoing clinical trials was retrieved from clinicaltrials.gov and available abstracts from research forums. Data was extracted from the most recent in vivo animal or clinical studies involving any of the following: (1) treatment with biomolecules, cells, or tissue-engineered constructs and (2) annulus fibrosus repair.

RESULTS

Seventy-five articles met the inclusion criteria for review. Among these, 17 studies involved humans; 37, small quadrupeds; and 21, large quadrupeds. Findings from all treatments employed demonstrated improvement either in regenerative capacity or in pain attenuation, with the exception of one clinical study.

CONCLUSION

Published clinical studies on cell therapy have reported encouraging results in the treatment of DDD and resultant back pain. We expect new data to emerge in the near future as treatments for DDD continue to evolve in parallel to our greater understanding of disk health and pathology.

Nonoperative management of discogenic back pain: a systematic review

STUDY DESIGN

Systematic review of the literature.

OBJECTIVE

A systematic evaluation of the literature was performed to investigate current nonoperative management of the treatment of discogenic low back pain.

SUMMARY OF BACKGROUND DATA

Back pain is a major health care concern with up to 39% being discogenic in origin according to one study. Nonoperative therapy is likely to be the initial treatment strategy for discogenic low back pain.

METHODS

PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for clinical studies evaluating nonoperative methods of treating discogenic back pain that were published between 2000 and 2012. Only prospective randomized controlled studies that compared a nonsurgical intervention with sham or placebo therapy were included. After removal of duplicate citations, a total of 226 articles were initially identified from the search terms. From these, we identified 11 randomized controlled trials (RCTs) from which data analysis was performed.

RESULTS

The 11 RCTs investigated traction therapy, injections, and ablative techniques. Results from 5 RCTs investigating methylene blue injection, steroid injection, ramus communicans ablation, intradiscal electrothermal therapy, and biacuplasty favored intervention over sham therapy. However, results from the study on methylene blue injections have not been replicated in other RCTs. Evaluation of the selection criteria used in the studies on ramus communicans ablation and intradiscal biacuplasty and a stratified analysis of results from the RCTs on intradiscal electrothermal therapy casts doubt on whether the conclusions from these RCTs can be applied to the general patient population with discogenic pain.

CONCLUSION

There are few high-quality studies evaluating nonoperative treatments for reducing discogenic low back pain. Although conclusions from several studies favor intervention over sham, it is unclear whether these interventions confer stable long-term benefit. There is some promise in newer modalities such as biacuplasty; however, more inclusive studies need to be performed.

Spinal traction promotes molecular transportation in a simulated degenerative intervertebral disc model

STUDY DESIGN

Biomechanical experiment using an in situ porcine model.

OBJECTIVE

To find the effect of traction treatment on annulus microstructure, molecular convection, and cell viability of degraded discs.

SUMMARY OF BACKGROUND DATA

Spinal traction is a conservative treatment for disc disorders. The recognized biomechanical benefits include disc height recovery, foramen enlargement, and intradiscal pressure reduction. However, the influence of traction treatment on annulus microstructure, molecular transportation, and cell viability of degraded discs has not been fully investigated.

METHODS

A total of 48 thoracic discs were dissected from 8 porcine spines (140 kg, 6-month old) within 4 hours after killing them and then divided into 3 groups: intact, degraded without traction, and degraded with traction. Each disc was incubated in a whole-organ culture system and subjected to diurnal loadings for 7 days. Except for the intact group, discs were degraded with 0.5 mL of trypsin on day 1 and a 5-hour fatigue loading on day 2. From day 4 to day 6, half of the degraded discs received a 30-minute traction treatment per day (traction force: 20 kg; loading: unloading = 30 s: 10 s). By the end of the incubation, the discs were inspected for disc height loss, annulus microstructure, molecular (fluorescein sodium) intensity, and cell viability.

RESULTS

Collagen fibers were crimped and delaminated, whereas the pores were occluded in the annulus fibrosus of the degraded discs. Molecular transportation and cell viability of the discs decreased after matrix degradation. With traction treatment, straightened collagen fibers increased within the degraded annulus fibrosus, and the annulus pores were less occluded. Both molecular transportation and cell viability increased, but not to the intact level.

CONCLUSION

Traction treatment is effective in enhancing nutrition supply and promoting disc cell proliferation of the degraded discs.

LEVEL OF EVIDENCE

N/A.

Controversies about interspinous process devices in the treatment of degenerative lumbar spine diseases: past, present, and future

A large number of interspinous process devices (IPD) have been recently introduced to the lumbar spine market as an alternative to conventional decompressive surgery in managing symptomatic lumbar spinal pathology, especially in the older population. Despite the fact that they are composed of a wide range of different materials including titanium, polyetheretherketone, and elastomeric compounds, the aim of these devices is to unload spine, restoring foraminal height, and stabilize the spine by distracting the spinous processes. Although the initial reports represented the IPD as a safe, effective, and minimally invasive surgical alternative for relief of neurological symptoms in patients with low back degenerative diseases, recent studies have demonstrated less impressive clinical results and higher rate of failure than initially reported. The purpose of this paper is to provide a comprehensive overview on interspinous implants, their mechanisms of action, safety, cost, and effectiveness in the treatment of lumbar stenosis and degenerative disc diseases.

The protective role of dynamic stabilization on the adjacent disc to a rigid instrumented level. An in vitro biomechanical analysis

OBJECTIVES

To assess the changes of intradiscal pressure at the bridged and at the adjacent levels to a lumbar two-level hybrid instrumentation.

INTRODUCTION

The elimination of motion produced by spinal fusion may have potential consequences beyond the index level overloading the juxtaposed spinal motion segments and leading to the appearance of degenerative changes. Degeneration of the segments adjacent to instrumented levels has become a topic of increasing interest in the literature over the last years. In order to prevent degenerative disc changes at the adjacent segments to a fused level, a broad scope of techniques have been developed, one of them is hybrid constructs.

METHODS

In 6 human cadaveric lumbosacral specimens, pressure transducers quantified intradiscal pressure changes at three levels (L3-L4, L4-L5 and L5-S1) under axial compression (0-750 N), anterior flexion (+12°) and extension (-12°) in three different situations of spinal stability: intact, L5-S1 rigid rod pedicle screw instrumentation and L4-S1 two-level hybrid instrumentation (rigid at L5-S1 and dynamic at L4-L5).

RESULTS

Once the L5-S1 segment had implanted the rigid instrumentation system (Diapason), the intradiscal pressure at this level decreased by 65 % while the intradiscal pressure at the disc above (L4-L5) increased 20 %. After augmenting the L5-S1 posterior construct with a dynamic stabilization device (Dynesys) at the superior adjacent level, the intradiscal pressure at this level, L4-L5, decreased by 50 % whereas intradiscal pressure at its adjacent level, L3-L4, only experienced a slight increase of 10 %.

CONCLUSIONS

The raise of intradiscal pressure at the adjacent segment to a rigid instrumented segment can be reduced when the rigid construct is augmented with a dynamic stabilization device. Hybrid constructs might have a possible protecting role preventing the occurrence of degenerative disc changes at the adjacent segment to a rigid instrumented level. Augmentation with a dynamic stabilization device might protect the disc above a rigid rod pedicle screw construct.

Role of lumbar interspinous distraction on the neural elements

The interspinous distraction devices are used to treat variable pathologies ranging from facet syndrome, diskogenic low back pain, degenerative spinal stenosis, diskopathy, spondylolisthesis, and instability. The insertion of a posterior element with an interspinous device (ISD) is commonly judged responsive to a relative kyphosis of a lumbar segment with a moderate but persistent increase of the spinal canal and of the foraminal width and area, and without influence on low-grade spondylolisthesis. The consequence is the need of shared specific biomechanical concepts to give for each degenerative problem the right indication through a critical analysis of all available experimental and clinical biomechanical data. We reviewed systematically the available clinical and experimental data about kyphosis, enlargement of the spinal canal, distraction of the interspinous distance, increase of the neural foramina, ligamentous structures, load of the posterior annulus, intradiskal pressure, strength of the spinous processes, degeneration of the adjacent segment, complications, and cost-effectiveness of the ISD. The existing literature does not provide actual scientific evidence over the superiority of the ISD strategy, but most of the experimental and clinical data show a challenging potential. These considerations are applicable with different types of ISD with only few differences between the different categories. Despite--or because of--the low invasiveness of the surgical implantation of the ISD, this technique promises to play a major role in the future degenerative lumbar microsurgery. The main indications for ISD remain lumbar spinal stenoses and painful facet arthroses. A clear documented contraindication is the presence of an anterolisthesis. Nevertheless, the existing literature does not provide evidence of superiority of outcome and cost-effectiveness of the ISD strategy over laminectomy or other surgical procedures. At this time, the devices should be used in clinical randomized independent trials in order to obtain more information concerning the most advantageous optimal indication or, in selected cases, to treat tailored indications.

Wallis interspinous implantation to treat degenerative spinal disease: description of the method and case series

The Wallis interspinous implant is most commonly used in the treatment of intervertebral disc herniation and for tears in the outer layer of the disc. The dynamic vertebral fixation concept was first initiated in 1984 with the goal of imitating the physiologic spinal kinetic. A total of 15 years later, a second generation of implant has been developed, termed the 'Wallis interspinous Implant', which aims to preserve the mobility of the operated spinal segment. To underline our own experience, a retrospective review of 15 patients that were treated with 'Wallis implantation' at our institution between January 2006 and March 2008. Our main inclusion criterion for Wallis implantation was low back pain because of degenerative lumbar spinal stenosis associated with segmental instability along with Modic changes 0-1 and with UCLA arthritic grade <II, while the main exclusion criteria were previous lumbar surgery, severe osteoporosis or degeneration UCLA grade >II in the adjacent two segments cephalad to implantation. The outcome was analyzed according to clinical and radiological parameters. One (n = 9), two (n = 4) and three levels (n = 2) were operated on using Wallis implantation, ranging from L2-L3 to L5-S1. We used implants of 8-14 mm in size. There was a reduction in low back pain (73 vs 43%) and gait disturbances (73 vs 14%) at the 3-month follow-up compared with preoperative values. In line with these results, the modified Japan Orthopedic Association Score (mJAOS) was increased from 12 preoperatively to 18 at 3 months and 20 at 12 months postoperatively. A reduction in low back pain could only be demonstrated for implants that were 10 mm in size or greater at 3 months and 12-15 months postoperatively. An improvement was seen in Modic grades after the operations as compared with those observed at preoperative MRI. The outcome in our patients was rated as good or excellent according to Odom's criteria in all cases, independent of the levels that were used. Wallis implantation is therefore a safe procedure with a good to excellent outcome in the short- and mid-term follow-up and can lead to disc rehydration, as confirmed by postoperative MRI. Principal postoperative (clinical) success is based on the correct implant size.

Healing of a painful intervertebral disc should not be confused with reversing disc degeneration: implications for physical therapies for discogenic back pain

BACKGROUND

Much is known about intervertebral disc degeneration, but little effort has been made to relate this information to the clinical problem of discogenic back pain, and how it might be treated.

METHODS

We re-interpret the scientific literature in order to provide a rationale for physical therapy treatments for discogenic back pain.

INTERPRETATION

Intervertebral discs deteriorate over many years, from the nucleus outwards, to an extent that is influenced by genetic inheritance and metabolite transport. Age-related deterioration can be accelerated by physical disruption, which leads to disc "degeneration" or prolapse. Degeneration most often affects the lower lumbar discs, which are loaded most severely, and it is often painful because nerves in the peripheral anulus or vertebral endplate can be sensitised by inflammatory-like changes arising from contact with blood or displaced nucleus pulposus. Surgically-removed human discs show an active inflammatory process proceeding from the outside-in, and animal studies confirm that effective healing occurs only in the outer anulus and endplate, where cell density and metabolite transport are greatest. Healing of the disc periphery has the potential to relieve discogenic pain, by re-establishing a physical barrier between nucleus pulposus and nerves, and reducing inflammation.

CONCLUSION

Physical therapies should aim to promote healing in the disc periphery, by stimulating cells, boosting metabolite transport, and preventing adhesions and re-injury. Such an approach has the potential to accelerate pain relief in the disc periphery, even if it fails to reverse age-related degenerative changes in the nucleus.

Lumbar disc rehydration postimplantation of a posterior dynamic stabilization system

Biological attempts at disc regeneration are promising; however, disc degeneration is closely related to other predisposing factors such as alteration of disc height, intradiscal pressure, load distribution, and motion. The restoration of the physiological status of the affected spinal segment is thus necessary prior to attempts at disc regeneration. Dynamic stabilization systems now offer the potential of a mechanical approach to intervertebral disc regeneration. The authors used decompression and placement of the BioFlex dynamic stabilization device to treat a young male patient with disc degeneration. This patient underwent follow-up, and he was found to gradually improve both neurologically and radiographically. On MR imaging performed 1 year postoperatively, he had an increase in disc height and disc rehydration. This case and the concept of disc rehydration are presented in this paper.

Effects of implantation of bone marrow mesenchymal stem cells, disc distraction and combined therapy on reversing degeneration of the intervertebral disc

Although success has been achieved with implantation of bone marrow mesenchymal stem cells (bMSCs) in degenerative discs, its full potential may not be achieved if the harsh environment of the degenerative disc remains. Axial distraction has been shown to increase hydration and nutrition. Combining both therapies may have a synergistic effect in reversing degenerative disc disease. In order to evaluate the effect of bMSC implantation, axial distraction and combination therapy in stimulating regeneration and retarding degeneration in degenerative discs, we first induced disc degeneration by axial loading in a rabbit model. The rabbits in the intervention groups performed better with respect to disc height, morphological grading, histological scoring and average dead cell count. The groups with distraction performed better than those without on all criteria except the average dead cell count. Our findings suggest that bMSC implantation and distraction stimulate regenerative changes in degenerative discs in a rabbit model.

Different Expression of Extracellular Matrix Genes : Primary vs. Recurrent Disc Herniation

OBJECTIVE

Recurrent lumbar disc herniation has been reported to occur in 5% to 15% of surgically treated primary lumbar disc herniation cases. We investigated the molecular biologic characteristics of primary herniated discs and recurrent discs to see whether the recurrent discs has the similar biological features with primary herniated discs.

METHODS

Primary herniated disc and recurrent disc cells were obtained by discectomy of lumbar disc patients and cells were isolated and then taken through monolayer cultures. We compared chondrogenic and osteogenic mRNA gene expression, and western blot between the two groups.

RESULTS

The mRNA gene expression of recurrent disc cells were increased 1.47* times for aggrecan, 1.38 times for type I collagen, 2.04 times for type II collagen, 1.22 times for both Sox-9 and osteocalcin, and 1.31 times for alkaline phosphatase, respectively, compared with the primary herniated lumbar disc cells (*indicates p < 0.05). Western blot results for each aggrecan, type I collagen, type II collagen, Sox-9, osteocalcin, and alkaline phosphatase were similar between the primary herniated disc cells and recurrent disc cells.

CONCLUSION

These results indicate that the recurrent disc cells have similar chondrogenic and osteogenic gene expression compared to primary herniated disc cells. Therefore, we assumed that the regeneration of remaining discs could fill the previous discectomy space and also it could be one of the factors for disc recurrence especially in the molecular biologic field.

A new porcine in vivo animal model of disc degeneration: response of anulus fibrosus cells, chondrocyte-like nucleus pulposus cells, and notochordal nucleus pulposus cells to partial nucleotomy

STUDY DESIGN

In vivo animal study.

OBJECTIVES

To describe a new porcine disc degeneration model, and to analyze disc remodeling and degeneration after nucleotomy with special view to the different nucleus pulposus (NP) cell types.

SUMMARY OF BACKGROUND DATA

Thus far, predominantly smaller animals were used for disc degeneration models; however, such small discs were inappropriate to investigate cell implementation therapies. Though notochordal cells (NCs) are important for disc formation and maintenance, differences in the amount of NCs between human and animal discs have often been neglected.

METHODS

Twenty-four Goettingen minipigs underwent partial nucleotomy with a 16G biopsy cannula, to remove approximately 10% of total NP volume. Animals were followed up for 3, or 24 weeks and analyzed by radiographs, MRIs, (immuno)histology, gene expression analysis, and biomechanical testing.

RESULTS

Three weeks after nucleotomy disc height was reduced by 26%, and magnetic resonance imaging signal intensity by 40%. At 24 weeks disc height was decreased by 32%. Increased degenerative changes were found in a histodegeneration score 3 and 24 weeks after nucleotomy, as well as considerable NP scarification after 3 weeks. In controls, cytokeratin-8 immunohistochemistry identified NCs in proximity to chondrocyte-like NP cells at approximately equal ratio. After nucleotomy, NCs were considerably reduced to <10% of total NP cells. Matrix genes were upregulated, except for aggrecan that decreased to 35% of initial values 3 weeks after nucleotomy. Matrix degrading factors (matrix metalloproteinases 13 and 3) were continuously upregulated, whereas transcripts of their inhibitors (tissue inhibitors of matrix metalloproteinase 2 and 3) were downregulated. No significant changes in segmental spinal flexibility or bone density were found after nucleotomy.

CONCLUSION

We introduced a new disc degeneration model with relatively large discs that could be used for cell therapeutic approaches. The study gives further information about disc remodeling after nucleotomy and indicates the relevance of an altered cellular composition for the development of disc degeneration.

Biomechanical characterization of an annulus-sparing spinal disc prosthesis

BACKGROUND CONTEXT

Current spine arthroplasty devices require disruption of the annulus fibrosus for implantation. Preliminary studies of a unique annulus-sparing intervertebral prosthetic disc (IPD) found that preservation of the annulus resulted in load sharing of the annulus with the prosthesis.

PURPOSE

Determine flexibility of the IPD versus fusion constructs in normal and degenerated human spines.

STUDY DESIGN/SETTING

Biomechanical comparison of motion segments in the intact, fusion and mechanical nucleus replacement states for normal and degenerated states. PATIENT SETTING: Thirty lumbar motion segments.

OUTCOMES MEASURES

Intervertebral height; motion segment range of motion, neutral zone, stiffness.

METHODS

Motion segments had multidirectional flexibility testing to 7.5Nm for intact discs, discs reconstructed using the IPD (n=12), or after anterior/posterior fusions (n=18). Interbody height and axial compression stiffness changes were determined for the reconstructed discs by applying axial compression to 1,500N. Analysis included stratifying results to normal mobile versus rigid degenerated intact motion segments.

RESULTS

The mean interbody height increase was 1.5mm for IPD reconstructed discs versus 3.0mm for fused segments. Axial compression stiffness was 3.0+/-0.9kN/mm for intact compared with 1.2+/-0.4kN/mm for IPD reconstructed segments. Reconstructed disc ROM was 9.0 degrees +/-3.7 degrees in flexion extension, 10.6 degrees +/-3.4 degrees in lateral bending, and 2.8 degrees +/-1.4 degrees in axial torsion that was similar to intact values and significantly greater than respective fusion values (p<.001). Mobile intact segments exhibited significantly greater rotation after fusion versus their more rigid counterparts (p<.05); however, intact motion was not related to motion after IPD reconstruction. The NZ and rotational stiffness followed similar trends. Differences in NZ between mobile and rigid intact specimens tended to decrease in the IPD reconstructed state.

CONCLUSION

The annulus-sparing IPD generally reproduced the intact segment biomechanics in terms of ROM, NZ, and stiffness. Furthermore, the IPD reconstructed discs imparted stability by maintaining a small neutral zone. The IPD reconstructed discs were significantly less rigid than the fusion constructs and may be an attractive alternative for the treatment of degenerative disc disease.

A novel minimally invasive percutaneous facet augmentation device for the treatment of lumbar radiculopathy and axial back pain: technical description, surgical technique and case presentations

OBJECTIVE: to describe a new posterior minimally invasive method of facet stabilization for treatment of the degenerating lumbar motion segment. The biomechanics of this Percudyn (Interventional Spine; Irvine, CA) system are distinct from that of other interspinous dynamic stabilization systems as it acts bilaterally directly within the middle column of the spine. Based on biomechanical evalution, the paired prosthesis supports, cushions, and reinforces the facet complexes by limiting both extension and lateral bending thereby maintaining central and foraminal volumes. METHODS: the Percudyn device consists of a pedicle anchor upon which sits a cushioning polycarbonate-urethane stabilizer that serves as a mechanically reinforcing stop between the inferior and superior articular facets. A 1.5 cm skin incision is made bilaterally over the lower pedicle of the treated segment through which a Jamshidi needle is percutaneously targeted under biplanar fluoroscopic guidance into the caudal aspect of the superior articular process directly underneath the lip of the inferior facet from the level above. Progressive onestep tubular dilation is then performed to secure a small disposable working portal. Through this access, the Percudyn stabilizers are then placed over the wire and anchored bilaterally into the inferior pedicles of the degenerated motion segment. RESULTS: three patients (ages 26-41, male) with significant low back pain as well as radiculopathy with lateral recess stenosis from a large disc herniation/ ligamentum and facet hypertrophy (L4-5 and/or L5-S1) underwent a minimally invasive decompression/ discectomy and bilateral Percudyn placement at each disease level. Each patient had significant relief of both his radiculopathy and axial back pain post-operatively and was discharged home within 18 hours without sequelae. CONCLUSION: this novel technique of percutaneous posterior facet augmentation allows for safe placement of bilateral middle column prostheses that act as mechanical cushions between the articulating facets thereby limiting extension and lateral bending and also preventing compression of the neural elements. As the Percudyn device serves to reinforce the middle column directly at the level of the facet, it represents a new class of posterior motionpreserving stabilization which may serve to mitigate segmental axial back pain as has been described for other posterior dynamic stabilization systems.

Age-related degeneration of lumbar intervertebral discs in rabbits revealed by deuterium oxide-assisted MRI

OBJECTIVES

Intervertebral disc (IVD) degeneration is associated with a loss of disc water content and change in biochemical composition of the disc. Rabbit is a frequently used model to evaluate the efficacy of therapeutics for disc degeneration. This study addresses whether rabbits undergo age-related disc degeneration, assessed using deuterium oxide-assisted magnetic resonance imaging (MRI) of the lumbar IVDs.

MATERIALS AND METHODS

The lumbar spines of adolescent, adult, and aged rabbits (6-36 months) were subjected to T2-weighted/short-tau inversion recovery (STIR) MRI scan along with water-deuterium oxide (H(2)O:D(2)O) dilutions. The total and maximum H(2)O:D(2)O index (HDi) of the lumbar IVDs were determined and compared between disc levels at different ages.

RESULTS

Adolescent rabbit lumbar discs had similar total HDi, suggesting the hydration and biochemical composition was similar among the lumbar levels. With the use of H(2)O:D(2)O reference, the discs were shown to undergo continual decrease in signal with aging which non-calibrated measurement method could not reveal. The HDi decrease rate was higher at the caudal than cranial levels.

CONCLUSION

This study provided in vivo evidence of age-related progressive disc degenerative change in rabbit lumbar discs, suggesting aged rabbits can be considered as a natural disc degeneration model in disc regeneration studies. However, it is important to select proper disc levels as intra-subject controls due to different rates of degenerative changes between caudal and cranial levels.