Discussion paper: what happened to the 'bio' in the bio-psycho-social model of low back pain?

PURPOSE

Over 20 years ago the term non-specific low back pain became popular to convey the limitations of our knowledge of the pathological source of most people's low back pain. Knowledge of underlying pathology has advanced little since then, despite limited improvements in outcomes for patients with low back pain.

METHODS

This paper discusses potential misunderstandings related to diagnostic studies in the field of low back pain and argues that future diagnostic studies should include and investigate pathological sources of low back pain.

RESULTS

Six potential misunderstandings are discussed. (1) Until diagnosis is shown to improve outcomes it is not worth investigating; (2) without a gold standard it is not possible to investigate diagnosis of low back pain; (3) the presence of pathology in some people without low back pain means it is not important; (4) dismissal of the ability to diagnose low back pain in clinical guidelines is supported by the same level of evidence as recommendations for therapy; (5) suggesting use of a diagnostic test in research is misinterpreted as endorsing its use in current clinical practice; (6) we seem to have forgotten the 'bio' in biopsychosocial low back pain.

CONCLUSIONS

We believe the misunderstandings presented in this paper partly explain the lack of investigation into pathology as an important component of the low back pain experience. A better understanding of the biological component of low back pain in relation, and in addition, to psychosocial factors is important for a more rational approach to management of low back pain.

Lumbar disc arthroplasty with Maverick disc versus stand-alone interbody fusion: a prospective, randomized, controlled, multicenter investigational device exemption trial

STUDY DESIGN

Randomized, controlled, multicenter, investigational device exemption trial.

OBJECTIVE

To investigate the safety and effectiveness of the first two-piece, metal-on-metal lumbar disc prosthesis for treating patients with single-level degenerative disc disease.

SUMMARY OF BACKGROUND DATA

For patients with degenerative disc disease unresponsive to conservative measures, lumbar disc arthroplasty provides an alternative to fusion designed to relieve persistent discogenic pain and maintain motion.

METHODS

After 2:1 randomization, 577 patients were treated in either the investigational group (405), receiving lumbar disc arthroplasty, or the control group (172), receiving anterior lumbar interbody fusion. Patients were evaluated preoperatively, at surgery/discharge, and at 1.5, 3, 6, 12, and 24 months after surgery. The primary study endpoint was overall success, a composite measure of safety and effectiveness as recommended by the Food and Drug Administration and defined in the protocol.

RESULTS

Both treatment groups demonstrated significant improvements compared with preoperative status. The investigational group had statistically superior outcomes (P < 0.05) at all postoperative evaluations in Oswestry Disability Index, back pain, and Short Form-36 Physical Component Summary scores as well as patient satisfaction. Investigational patients had longer surgical times (P < 0.001) and greater blood loss (P < 0.001) than did control patients; however, hospitalization stays were similar for both groups. Investigational patients had fewer implant or implant/surgical procedure-related adverse events (P < 0.001). Return-to-work intervals were reduced for investigational patients. Disc height and segmental angular motion were maintained throughout the study in the investigational group. In the investigational group, overall success superiority was found when compared to the control group as defined by the Food and Drug Administration Investigational Device Exemption protocol.

CONCLUSION

The investigational group consistently demonstrated statistical superiority versus fusion on key clinical outcomes including improved physical function, reduced pain, and earlier return to work.

An organ culture system to model early degenerative changes of the intervertebral disc

INTRODUCTION

Back pain, a significant source of morbidity in our society, is related to the degenerative changes of the intervertebral disc. At present, the treatment of disc disease consists of therapies that are aimed at symptomatic relief. This shortcoming stems in large part from our lack of understanding of the biochemical and molecular events that drive the disease process. The goal of this study is to develop a model of early disc degeneration using an organ culture. This approach is based on our previous studies that indicate that organ culture closely models molecular events that occur in vivo in an ex vivo setting.

METHODS

To mimic a degenerative insult, discs were cultured under low oxygen tension in the presence of TNF-α, IL-1β and serum limiting conditions.

RESULTS

Treatment resulted in compromised cell survival and changes in cellular morphology reminiscent of degeneration. There was strong suppression in the expression of matrix proteins including collagen types 1, 2, 6 and 9, proteoglycans, aggrecan and fibromodulin. Moreover, a strong induction in expression of catabolic matrix metalloproteinases (MMP) 3, 9 and 13 with a concomitant increase in aggrecan degradation was seen. An inductive effect on NGF expression was also noticed. Although similar, nucleus pulposus and annulus fibrosus tissues showed some differences in their response to the treatment.

CONCLUSIONS

Results of this study show that perturbations in microenvironmental factors result in anatomical and gene expression change within the intervertebral disc that may ultimately compromise cell function and induce pathological deficits. This system would be a valuable screening tool to investigate interventional strategies aimed at restoring disc cell function.

Diagnostic tools and imaging methods in intervertebral disk degeneration

Low back pain has a negative impact on the economy and society. Intervertebral disk degeneration is linked to the occurrence of low back pain. MRI provides three-dimensional morphologic and biochemical information regarding the status of the disk. This article reviews new and evolving MRI disk-imaging techniques, including grading, relaxation-time measurements, diffusion, and contrast perfusion. In addition, high-resolution magic-angle spinning methods to correlate in vitro disk degeneration (with pain, etc) and in vivo spectroscopic results are discussed. With the potential for morphologic and biochemical characterization of the intervertebral disk, MRI shows promise as a tool to quantitatively assess disk health.

Management of degenerative disk disease and chronic low back pain

Degenerative disk disease is a strong etiologic risk factor of chronic low back pain (LBP). A multidisciplinary approach to treatment is often warranted. Patient education, medication, and cognitive behavioral therapies are essential in the treatment of chronic LBP sufferers. Surgical intervention with a rehabilitation regime is sometimes advocated. Prognostic factors related to the outcome of different treatments include maladaptive pain coping and genetics. The identification of pain genes may assist in determining individuals susceptible to pain and in patient selection for appropriate therapy. Biologic therapies show promise, but clinical trials are needed before advocating their use in humans.

Temporal interactions of degenerative changes in individual components of the lumbar intervertebral discs: a sequential magnetic resonance imaging study in patients less than 40 years of age

STUDY DESIGN

A retrospective longitudinal observational study using baseline and follow-up magnetic resonance imaging (MRI).

OBJECTIVE

To study the natural history of disc degeneration, focusing on the significance of changes affecting the individual components of the intervertebral disc.

SUMMARY OF BACKGROUND DATA

The natural history of the degenerative disc disease is poorly understood. Focusing on the relative prevalence, temporal evolution, and interactions of pathology in the anulus fibrosus, nucleus pulposus, and the end plates can help in better understanding of this process.

METHODS

MRIs of the lumbar spine in 63 patients, obtained at a mean interval of 30 months, were evaluated independently by two neuroradiologists to assess the temporal evolution of degeneration changes in 378 discs between T12 through S1 segments. In addition, a direct side-by-side comparison of two studies was also performed. Statistical analysis was performed to assess the association between the degeneration of individual disc components and to find the predictors of future degeneration.

RESULTS

Radial anular tears and end plate defects were associated with worse nuclear degeneration at the time of the initial study. Both end plate defects and nuclear degeneration were rare in the absence of radial tears. Multiple nominal logistic regression analysis showed that radial tears and herniation at the time of the initial study, along with the duration between the two imaging studies were the significant predictors of worsening nuclear degeneration. Age, sex, and the segmental disc level did not show any significant association with temporal progression of nuclear degeneration.

CONCLUSION

Radial tears and herniation are significant predictors of progressive nuclear degeneration, which was not seen in the absence of radial tears. End plate defects also frequently occur before nuclear degeneration but rarely in the absence of anular tears.

Minimally invasive axial presacral L5-S1 interbody fusion: two-year clinical and radiographic outcomes

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The primary aim of this study was to evaluate and report the 2-year clinical and radiographic outcomes associated with a L5-S1 interbody fusion procedure that employs an axial presacral surgical approach.

SUMMARY OF BACKGROUND DATA

There are a number of lumbar interbody fusion procedures used to treat painful, degenerated discs. However, despite their procedural differences (e.g., anterior vs. posterior), all of the current surgical approaches are undertaken in the same anatomical plane that requires disruption of musculoligamentous and osseous support structures as well as vascular and neurologic tissue to gain access the intervertebral disc space. The presacral procedure is distinct in that it uses an approach along an axis essentially perpendicular to the anatomical plane of traditional fusion procedures.

METHODS

One hundred fifty-six patients from four clinical sites were selected for inclusion if they underwent a L5-S1 interbody fusion via the presacral approach with the AxiaLIF system (TranS1, Wilmington, NC) and had both presurgical and 2-year radiographic or clinical follow-up. Back pain and functional impairment were evaluated with an 11-point numeric scale and the Oswestry Disability Index (ODI), respectively, preoperatively and at 2 years. Standard radiographic imaging techniques were used to determine fusion status.

RESULTS

Marked clinical improvements were realized in back pain severity and functional impairment through 2 years of follow-up. Mean pain scores improved from 7.7 ± 1.6 (n = 155) preoperatively to 2.7 ± 2.4 (n = 148) at 24 months, reflecting an approximate 63% overall improvement (P < 0.001). Mean ODI scores improved from 36.6 ± 14.6% (n = 86) preoperatively to 19.0 ± 19.2% (n = 78) at 24 months, or approximately 54% (P < 0.001). Two-year clinical success rates on the basis of change relative to baseline of at least 30% were 86% (127 of 147) and 74% (57 of 77) for pain and function, respectively. The overall radiographic fusion rate at 2 years was 94% (145 of 155).

CONCLUSION

Findings from this clinical series of patients treated with a presacral interbody fusion procedure, stabilized with the AxiaLIF rod, reflect favorable and durable outcomes through 2 years of follow-up.

Mechanical deformation and glycosaminoglycan content changes in a rabbit annular puncture disc degeneration model

STUDY DESIGN

Evaluation of degenerated intervertebral discs from a rabbit annular puncture model by using specialized magnetic resonance imaging (MRI) techniques, including displacement encoding with stimulated echoes and a fast-spin echo (DENSE-FSE) acquisition and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC).

OBJECTIVE

To evaluate a rabbit disc degeneration model by using various MRI techniques. To determine the displacements and strains, spin-lattice relaxation time (T1), and glycosaminoglycan (GAG) distribution of degenerated discs as compared to normal and adjacent level discs.

SUMMARY OF BACKGROUND DATA

Annular puncture of the intervertebral disc produces disc degeneration in rabbits. DENSE-FSE has been previously demonstrated in articular cartilage for the measurement of soft tissue displacements and strains. MRI also can measure the T1 of tissue, and dGEMRIC can quantify GAG concentration in cartilage. METHODS.: In eight New Zealand white rabbits, the annulus fibrosis of a lumbar disc was punctured. After 4 weeks, the punctured and cranially adjacent motion segments were isolated for MRI and histology. MRI was used to estimate the disc volume and map T1. DENSE-FSE was used to determine displacements for the estimation of strains. dGEMRIC was then used to determine GAG distributions.

RESULTS

Histology and standard MRI indicated degeneration in punctured discs. Disc volume increased significantly at 4 weeks after the puncture. Displacement of the nucleus pulposus was distinct from that of the annulus fibrosis in most untreated discs but not in punctured discs. T1 was significantly higher and GAG concentration significantly lower in punctured discs compared with untreated adjacent level discs.

CONCLUSION

Noninvasive and quantitative MRI techniques can be used to evaluate the mechanical and biochemical changes that occur with animal models of disc degeneration. DENSE-FSE, dGEMRIC, and similar techniques have potential for evaluating the progression of disc degeneration and the efficacy of treatments.

Thermosensitive chitosan-gelatin-glycerol phosphate hydrogel as a controlled release system of ferulic acid for nucleus pulposus regeneration

In the degenerative disc, overproduction of reactive oxygen species (ROS) involves in apoptosis and senescence of nucleus pulposus (NP) cells that could accelerate the degenerative process. Ferulic acid (FA) has been reported to have an excellent antioxidant property. In the study, injectable thermosensitive chitosan/gelatin/glycerol phosphate (C/G/GP) hydrogel was applied as a controlled release system for FA delivery. The study was aimed to evaluate possible therapeutic effects of FA-incorporated C/G/GP hydrogel on hydrogen peroxide (H(2)O(2))-induced oxidative stress NP cells. The results showed that the release of FA from C/G/GP hydrogel could decrease the H(2)O(2)-induced oxidative stress. Post-treatment of FA-incorporated C/G/GP hydrogel on H(2)O(2)-induced oxidative stress NP cells showed up-regulation of Aggrecan and type II collagen and down-regulation of MMP-3 in mRNA level. The results of sulfated-glycosaminoglycans (GAGs) to DNA ratio and alcian blue staining revealed that the GAGs production of H(2)O(2)-induced oxidative stress NP cells could reach to normal level. The results of caspase-3 activity and TUNEL staining indicated that FA-incorporated C/G/GP hydrogel decreased the apoptosis of H(2)O(2)-induced oxidative stress NP cells. The results suggested that the C/G/GP hydrogel was very suitable for sustained delivery of FA. The FA-incorporated C/G/GP hydrogel would be used to treat the degenerative disc in the early stage before it developed into the latter irreversible stages.

Percutaneous treatment of intervertebral disc herniation

Interventional radiology plays a major role in the management of symptomatic intervertebral disc herniations. In the absence of significant pain relief with conservative treatment including oral pain killers and anti-inflammatory drugs, selective image-guided periradicular infiltrations are generally indicated. The precise control of needle positioning allows optimal distribution of steroids along the painful nerve root. After 6 weeks of failure of conservative treatment including periradicular infiltration, treatment aiming to decompress or remove the herniation is considered. Conventional open surgery offers suboptimal results and is associated with significant morbidity. To achieve minimally invasive discal decompression, different percutaneous techniques have been developed. Their principle is to remove a small volume of nucleus, which results in an important reduction of intradiscal pressure and subsequently reduction of pressure inside the disc herniation. However, only contained disc herniations determined by computed tomography or magnetic resonance are indicated for these techniques. Thermal techniques such as radiofrequency or laser nucleotomy seem to be more effective than purely mechanical nucleotomy; indeed, they achieve discal decompression but also thermal destruction of intradiscal nociceptors, which may play a major role in the physiopathology of discal pain. The techniques of image-guided spinal periradicular infiltration and percutaneous nucleotomy with laser and radiofrequency are presented with emphasis on their best indications.

Engineering of polymer-based grafts with cells derived from human nucleus pulposus tissue of the lumbar spine

Intervertebral disc degeneration is considered a major source of low back pain. We therefore examined an absorbable polyglycolic acid (PGA) biomaterial for its utility to support disc tissue regeneration. Microdiscectomy for lumbar disc herniation was performed in six patients. Intervertebral disc cells were isolated and in vitro cell expansion was accomplished using human serum and FGF2. In a fibrin-hyaluronan solution, disc cells were loaded on PGA scaffolds and cultured for 2 weeks. Formation of disc tissue was documented by histological staining of the extracellular matrix as well as gene expression analysis of typical disc marker genes. The use of human serum and FGF2 ensures efficient isolation and expansion of human disc cells. During this phase, dedifferentiation of the disc cells was observed. Subsequent 3D tissue culture of disc cells in PGA scaffolds, however, is accompanied by the induction of typical disc marker genes, resulting in tissue containing glycosaminoglycans and collagens. Propidium iodide/fluorescein diacetate (PI/FDA) staining documented that 3D assembly of disc cells in PGA scaffolds allows prolonged culture and high viability of disc cells. Disc cells from tissue of the nucleus compartment can be reliably isolated and expanded in vitro with FGF. In combination with a fibrin-hyaluronan solution and loaded on a PGA scaffold, disc cells from expansion culture commence a redifferentiation process. PGA-based scaffolds could be useful as temporal matrices for regenerative disc repair approaches.

Attenuation of inflammatory events in human intervertebral disc cells with a tumor necrosis factor antagonist

STUDY DESIGN

The inflammatory responses of primary human intervertebral disc (IVD) cells to tumor necrosis factor α (TNF-α) and an antagonist were evaluated in vitro.

OBJECTIVE

To investigate an ability for soluble TNF receptor type II (sTNFRII) to antagonize TNF-α-induced inflammatory events in primary human IVD cells in vitro.

SUMMARY OF BACKGROUND DATA

TNF-α is a known mediator of inflammation and pain associated with radiculopathy and IVD degeneration. sTNFRs and their analogues are of interest for the clinical treatment of these IVD pathologies, although information on the effects of sTNFR on human IVD cells remains unknown.

METHODS

IVD cells were isolated from surgical tissues procured from 15 patients and cultured with or without 1.4 nmol/L TNF-α (25 ng/mL). Treatment groups were coincubated with varying doses of sTNFRII (12.5-100 nmol/L). Nitric oxide (NO), prostaglandin E₂ (PGE₂), and interleukin-6 (IL6) levels in media were quantified to characterize the inflammatory phenotype of the IVD cells.

RESULTS

Across all patients, TNF-α induced large, statistically significant increases in NO, PGE₂, and IL6 secretion from IVD cells compared with controls (60-, 112-, and 4-fold increases, respectively; P < 0.0001). Coincubation of TNF-α with nanomolar doses of sTNFRII significantly attenuated the secretion of NO and PGE₂ in a dose-dependent manner, whereas IL6 levels were unchanged. Mean IC₅₀ values for NO and PGE₂ were found to be 35.1 and 20.5 nmol/L, respectively.

CONCLUSION

Nanomolar concentrations of sTNFRII were able to significantly attenuate the effects of TNF-α on primary human IVD cells in vitro. These results suggest this sTNFR to be a potent TNF antagonist with potential to attenuate inflammation in IVD pathology.

Adalimumab for the Treatment of Refractory Sciatica Induced by Disc Prolapse

Ten patients with back pain and sciatica were selected according to certain inclusion criteria for a study to assess the efficacy of the Anti TNF agent Adalimumab in the treatment of refractory sciatica pain induced by a lumbar disc prolapse in patients who failed to improve following lumbar epidural steroid or disc surgery. Each was given a subcutaneous injection of 40mg Adalimumab repeated after two weeks. Patients were assessed regularly on weeks 0, 2, 4 and 8 employing the Visual Analogue Score (VAS) for leg pain and back pain and the Straight Leg Raising (SLR) test. The median improvement of the leg pain VAS was 55. Median improvements of back pain VAS was 37. Median improvement of the SLR was 45. The study demonstrated the beneficial effect of adalimumab therapy in reducing the back and leg pain associated with sciatica in this difficult to treat group of patients. The improvement of leg pain was more significant than that of back pain. The response was better in patients with symptoms of shorter duration and with less SLR restriction at base line.

Expression of leptin, leptin receptor, and connective tissue growth factor in degenerative disk lesions in the wrist

PURPOSE

The purpose of this study was to identify whether leptin and connective tissue growth factor (CTGF) occur in the degenerative fibrocartilage disk and whether cartilage cells express leptin receptors.

METHODS

The study included 23 patients diagnosed with degenerative articular disk tears of the triangular fibrocartilage (TFC) (Palmer type 2C). Patients were divided into 2 groups based on ulna length: 1 group consisted of patients with an ulna-positive variance (group A), and the other group included patients with ulna-negative or -neutral variance (group B). After arthroscopic debridement of the TFC, histologic sections of biopsy specimens were prepared. The biopsy specimens were immunohistochemically analyzed, and the quantity of leptin-, CTGF-, and leptin receptor-positive cells was assessed.

RESULTS

Cells positive for leptin, leptin receptor, and CTGF were found. The number of cells positive for leptin was significantly increased in specimens of patients with an ulna-negative variance (group B). In contrast, no significant difference was found for leptin receptor and CTGF in biopsy specimens of patients with ulna-positive or ulna-negative/neutral variance. The inner, middle, and outer zones of the disk do not express significantly different quantities of marker-positive cells.

CONCLUSIONS

Degenerative fibrocartilage disk tissue cells exhibit leptin receptors and are exposed to the markers leptin and CTGF, providing evidence of a local paracrine system and regenerative processes. Cells of disks from patients with an ulna-neutral/negative length express significantly higher numbers of leptin-positive cells.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Cellular and molecular actions of Methylene Blue in the nervous system

Methylene Blue (MB), following its introduction to biology in the 19th century by Ehrlich, has found uses in various areas of medicine and biology. At present, MB is the first line of treatment in methemoglobinemias, is used frequently in the treatment of ifosfamide-induced encephalopathy, and is routinely employed as a diagnostic tool in surgical procedures. Furthermore, recent studies suggest that MB has beneficial effects in Alzheimer's disease and memory improvement. Although the modulation of the cGMP pathway is considered the most significant effect of MB, mediating its pharmacological actions, recent studies indicate that it has multiple cellular and molecular targets. In the majority of cases, biological effects and clinical applications of MB are dictated by its unique physicochemical properties including its planar structure, redox chemistry, ionic charges, and light spectrum characteristics. In this review article, these physicochemical features and the actions of MB on multiple cellular and molecular targets are discussed with regard to their relevance to the nervous system.

Inter- and intraobserver reliability in radiographic assessment of degenerative disk disease

Clinicians use descriptive classification systems when treating patients with low back pain as an adjunct to surgical decision making. Magnetic resonance imaging (MRI) changes, including Modic changes, the presence of a high-intensity zone, and internal disk desiccation, are commonly used descriptors. The question remains whether different clinicians interpret these terms similarly. This study evaluated the inter- and intraobserver reliability of commonly used MRI classifications in patients presenting with low back pain.Sixty-six patients who underwent lumbar spine fusion surgery at a single multiphysician spine specialty practice for degenerative disk disease were identified. For each surgical level, the following MRI variables were determined independently by 3 fellowship-trained spine surgeons: presence or absence of high-intensity zone and/or internal disk desiccation, presence and classification of disk herniation, Modic grade, and disk height. Each surgeon reviewed the same set of MRI studies a second time at least 2 weeks from the first reading. Inter- and intraobserver reliability was determined using multiobserver Kappa coefficients. Intraobserver reliability ranged from 0.563 to 0.988, with greatest agreement in determining disk height. The greatest interobserver agreement was for determining Modic changes (0.819).Controversy remains on the criteria for diagnosing degenerative disk disease. In patients presenting with low back pain diagnosed with degenerative disk disease, the inter- and intraobserver reliability with use of several common MRI diagnostic tools was substantial. These data imply that clinicians interpret these findings in a reproducible fashion and interpret these terms similarly.

The expression of tumor necrosis factor-α and CD68 in high-intensity zone of lumbar intervertebral disc on magnetic resonance image in the patients with low back pain

STUDY DESIGN

Several recent studies suggest a high-intensity zone (HIZ) within the posterior annulu of lumbar intervertebral disc seen on T2-weighted magnetic resonance (MR) images represents the inflammation in the annulus, an annular tear, and/or vascular granulation tissue. It has not be reported yet whether there is the expression of tumor necrosis factor (TNF-α) and inflammatory cells appear in HIZ of intervertebral disc on MR images.

OBJECTIVE

To study whether HIZ is a specific signal for the inflammatory reaction of painful intervertebral disc.

SUMMARY OF BACKGROUND DATA

The presence of HIZ signal within the posterior annulus seen on sagittal T2-weighted spin-echo magnetic imaging sequences has already been used in the diagnosis of painful annular tears in the last decade. There have been studies suggesting that the presence of HIZ reflects inflammation in the annulus, an annular tear, and/or vascular granulation tissue.

METHODS

Twenty-six consecutive patients with low back pain underwent MR images and discography (age range = 26-65 years; mean age = 47.5 years; 16 men, 10 women). In all the patients, HIZ appeared in the involved intervertebral discs on T2-weighted MR images. Lumbar discography was usually performed on each patient for the discs L3-L4, L4-L5, and L5-S1. All patients received posterior lumbar interbody fusion procedures. The intervertebral disc specimens contained HIZ were excised en bloc during posterior interbody fusion. The distribution of TNF-α and CD68 in the intervertebral disc specimens within HIZ on MR images from 26 consecutive patients with low back pain and in the intervertebral disc specimens from five fresh cadavers were observed.

RESULTS

The histologic study of the consecutive sagittal slices of the HIZ showed a lot of proliferated small round cells and fibroblasts. There were a lot of TNF-α positive cells and some CD68 positive cells in HIZ and the number of TNF-α and CD68 positive cells in HIZ was significantly higher than that in the annulus fibrosus around HIZ and in the control (P < 0.05).

CONCLUSION

The results of this study indicate that HIZ may be a specific signal for the inflammatory reaction of painful intervertebral disc.

Pharmacological inhibition of tumor necrosis factor may reduce pain behavior changes induced by experimental disc puncture in the rat: an experimental study in rats

STUDY DESIGN

Pain behavior assessment in rats following disc puncture (DP) and simultaneous tumor necrosis factor (TNF) inhibition.

OBJECTIVE

To assess if treatment with TNF inhibition could reduce the pain behavior changes induced by DP in the rat.

SUMMARY OF BACKGROUND DATA

Anular tears with leakage of nucleus pulposus have been suggested to be one possible cause of low back pain (LBP). In an experimental model, it was recently shown that DP might induce specific pain behavior changes. The aim of the present study was to a study if inhibition of TNF might reduce such pain behavior changes.

METHODS

Sixty rats underwent facetectomy and puncture of the fourth lumbar disc. The rats were simultaneously treated with doxycycline locally at 0.3 and 3.0 mg/kg and systemically at 3.0 mg/kg, or infliximab locally at 0.5 and 5.0 mg/kg, and systemically at 5.0 mg/kg, (n ∇ 10 for each subseries). The rats were videotaped at 1, 3, 7, 14, and 21 days after surgery. The videos were analyzed regarding presence of wet-dog shakes (WDS). Data from a previous study with sham surgery and DP without treatment were included for comparison.

RESULTS

All groups treated with doxycycline resulted in a statistically significant reduction of WDS compared to the group without treatment (DP). In infliximab treated animals, WDS decreased with statistically significance compared to the nontreated DP group at all analyzed days except for the group with high dose local treatment where a statistically significant reduction was obtained only at days 14 and 21.

CONCLUSION

The present study showed that TNF inhibition induced a marked reduction of wet dog shakes. It is not fully understood if wet-dog shakes may relate to LBP, but in view of recent clinical findings one may consider clinical studies of TNF inhibition for the treatment of LBP.

Percutaneous diode laser irradiation for lumbar discogenic pain: a clinical study

The present study evaluated the efficiency of laser irradiation for treating discogenic low back pain. Discogenic low back pain is believed to result from the degeneration and disruption of outer fibers of the intervertebral disc annulus, leading to a cycle of persistent inflammation, damage to the disc matrix, and sensitization of developed annular nociceptors. We selected 11 patients as subjects on the basis of clinical findings and the results of provocative disc blockade. The patients underwent percutaneous irradiation of affected lumbar discs with a diode laser. The mean total irradiation energy per disc was 740 ± 2.51 J, with a range of 610 to 960 J. The patients' responses were assessed with the Oswestry Disability Index (ODI) and a visual analogue scale (VAS) to determine the average level of pain. The patients' mean ODI scores at 1 day, 3 months, 6 months, 12 months, 18 months, and 24 months after laser irradiation were 18.63 ± 11.22, 13.6 ± 4.53, 12.5 ± 5.5, 11.8 ± 5.25, 10.5 ± 2.27, and 10.5 ± 2.27, respectively, versus a mean pre-treatment ODI score of 50.27 ± 9.35. Their mean VAS scores at the same post-treatment intervals were 3.09 ± 2.36, 2.4 ± 0.97, 2.7 ± 1.16, 2.1 ± 0.74, 2.1 ± 0.81, and 2.1 ± 0.88, respectively, versus a mean pre-treatment VAS score of 7.64 ± 1.21. The post- versus pre-treatment scores for both the ODI and VAS indicated a statistically significant clinical benefit across the full 24-month follow-up period after laser irradiation. The efficacy of laser irradiation in treating such pain may come from a thermal effect and reductions of intradiscal pressure, of the concentrations of irritant substances, and of the numbers of nociceptors in the affected region.

Intradiscal injection therapy for degenerative chronic discogenic low back pain with end plate Modic changes

BACKGROUND CONTEXT

The effect of intradiscal steroid therapy for patients with degenerative chronic discogenic low back pain remains an issue of debate.

PURPOSE

To evaluate the effect of various intradiscal injection regimens for patients with degenerative chronic discogenic low back pain and end plate Modic changes.

STUDY DESIGN

Double-blind, randomized, controlled, prospective clinical study.

PATIENT SAMPLE

One hundred twenty patients with discogenic low back pain and end plate Modic changes on magnetic resonance imaging (MRI) who received discography but were unwilling to accept surgical operation.

OUTCOME MEASURES

Pain and function were determined by the visual analog scale (VAS) and the Oswestry Disability Index (ODI) assessment.

METHODS

Patients who received diagnostic discography for suspected degenerative discogenic low back pain were recruited. A total of 120 patients with positive discography and end plate Modic changes at a single level were enrolled in the study and allocated into Groups A and B according to the type of Modic changes on MRI. Then, the patients in Groups A and B were randomized into three subgroups, respectively. Intradiscal injection of normal saline was performed in Subgroups A1 and B1, intradiscal injection of diprospan was performed in Subgroups A2 and B2, and intradiscal injection of a mixed solution of diprospan+songmeile (cervus and cucumis polypeptide) was performed in Subgroups A3 and B3. The clinical outcome of each patient was evaluated and recorded by using the VAS and ODI at 3 and 6 months after the procedure.

RESULTS

The subgroups were comparable with respect to gender, age, pain, and percentage disability. Neither VAS pain scores nor Oswestry function scores of the patients within Group A had any improvement at 3 or 6 months after saline injection, but both of them improved significantly at the two time points after diprospan and diprospan+songmeile injection, respectively. Meanwhile, the latter two injection protocols led to no significant difference in pain relief and functional recovery. Similar results were obtained in patients within Group B. Furthermore, no difference of the improvement of VAS pain scores or Oswestry function scores was found between the patients within Group A and within Group B at different time points after various interventions.

CONCLUSION

Intradiscal injection of corticosteroids could be a short-term efficient alternative for discogenic low back pain patients with end plate Modic changes on MRI who were still unwilling to accept surgical operation when conservative treatment failed.

Interaction of 5-hydroxytryptamine and tumor necrosis factor-α to pain-related behavior by nucleus pulposus applied on the nerve root in rats

STUDY DESIGN

The effects of exogenous 5-hydroxytryptamine (5-HT), tumor necrosis factor(TNF)-α, 5-HT + TNF in combination, and autologous nucleus pulposus (NP) at dorsal root ganglion (DRG) were examined using rat models.

OBJECTIVE

To examine the interaction of 5-HT with TNF for pain-related behavior in a rat lumbar disc herniation (LDH) model.

SUMMARY OF BACKGROUND DATA

5-HT and TNF have been shown to play roles in sciatica in lumbar disc herniation as chemical factors.

METHODS

Adult female Sprague-Dawley rats were divided into six groups: 5-HT group, TNF group, 5-HT + TNF (combination) group, NP group, control group, and naive group. Von Frey tests were used for pain-related behavior testing. Expressions of activating transcription factor 3 and calcitonin gene-related peptide (CGRP) were evaluated immunohistochemically. Expressions of TNF, TNF receptor 1 (TNFR1), and 5-HT2A receptors in the left L5 DRG were examined using western blotting. Plasma levels of 5-hydroxyindole acetic acid, a metabolite of 5-HT, were measured.

RESULTS

Mechanical withdrawal thresholds were significantly decreased in the 5-HT, TNF, combination, and NP groups compared with controls. Thresholds recovered after 14 days in the 5-HT and TNF groups, and after 28 days in the combination group. Exogenous 5-HT and TNF to the nerve root induced pain-related behavior and lasted for a shorter period compared with combination and NP groups. Activating transcription factor 3- and calcitonin gene-related peptide-immunoreactive DRG neurons were significantly increased only in the early phase in 5-HT, TNF, combination, and NP groups. TNF induced 5-HT2A receptor expressions in the DRG, while 5-HT induced TNF and TNF receptor 1 expressions.

CONCLUSION

The present findings suggest that both 5-HT and TNF induce pain-related behavior and interact with each other to prolong pain-related behavior in a rat LDH model.

The effect of methylene blue on peridural fibrosis formation after laminectomy in rats: an experimental novel study

BACKGROUND CONTEXT

Despite progress in surgical techniques, some patients still face postoperative recurrence of pain, although the rate of successful outcomes is estimated to be approximately 70% and 86% after primary decompression spinal surgery. Recently, attention has been focused on peridural fibrosis (PF), which may be responsible for recurrent pain after laminectomy or discectomy. Methylene blue (MB) has been shown to prevent fibrosis formation in various tissues.

PURPOSE

The aims of this study were to investigate the effects of MB and assess the effects of different doses on the prevention of postlaminectomy fibrosis formation in a rat model. This preclinical model is a potential platform for future clinical trials to identify an effective agent for the prevention of clinically important epidural scar formation.

STUDY DESIGN

An established bilateral L5-L6 rat laminectomy model was used to evaluate postlaminectomy PF with macroscopic and microscopic analyses.

PATIENT SAMPLE

Seventy-five male adult white Sprague-Dawley rats that underwent laminectomy at the L5-L6 levels were divided into five groups of 15 rats each.

OUTCOME MEASURES

Dissected specimens were evaluated macroscopically and microscopically by examiners who were unaware of the group assignment to record the presence or absence of PF formation.

METHODS

Groups A and B served as controls and Groups C, D, and E received treatment. Group A (sham) underwent laminectomy, and Group B was treated with normal saline at the laminectomy site. Rats in Groups C, D, and E received 0.1 mL MB at concentrations of 0.5%, 1%, and 2%, respectively, at the laminectomy site. All rats were killed 4 weeks after laminectomy. The results were compared statistically with the nonparametric Kruskal-Wallis test and Poisson regression.

RESULTS

Peridural fibrosis was found in five rats (33%) in control Groups A and B and in two rats (10%) in MB-treated laminectomy Groups C and D. The difference between control and MB groups was not statistically significant (p = .27). The preventive effect of MB on PF was not seen at the highest dose of MB (2%) in Group E. Severity of fibrosis was lower in Groups C (MB 0.5%) and D (MB 1%) than in Group E (MB 2%) (p < .01). Wound healing was not affected, and there was no cerebrospinal fluid leakage. No neurological deficits were seen.

CONCLUSION

Low doses of MB may be an effective agent in preventing PF formation after lumbar laminectomy in rats. Clinical significance and safety in human use are currently undetermined.

Effect of honey on peridural fibrosis formation after laminectomy in rats: a novel experimental study

Despite progress in surgical techniques, some patients still face postoperative recurrence of pain. Recently, more attention has been focused on peridural fibrosis (PF), which may be responsible for recurrent pain after laminectomy or discectomy. Honey has been shown to exert anti-inflammatory effects on exposed tissues besides its well-known antibacterial properties. The aim of this study were to investigate the effects of honey on the prevention of postlaminectomy fibrosis formation in a rat model. A controlled blinded study was performed in 45 male adult white Sprague-Dawley rats that underwent laminectomy at the L5-L6 levels. They were divided into 3 groups (A, B, and C) of 15 rats each. Group A (sham) underwent laminectomy and group B was treated with normal saline at the laminectomy site. Rats in group C received 0.1 mL honey at the laminectomy site. All rats were killed 4 weeks after laminectomy. PF was found in 5 rats (33%) of control groups A and B, and in 2 rats (10%) in honey-treated laminectomy group C. The difference was not statistically significant. Wound healing was not affected, and there was no cerebrospinal fluid leakage. Although honey appears to be safe, it cannot cause a significant reduction of PF formation after lumbar laminectomy in rats.

Treatment of discogenic low back pain with Intradiscal Electrothermal Therapy (IDET): 24 months follow-up in 50 consecutive patients

BACKGROUND

Degeneration of the intervertebral disc can be the source of severe low back pain. Intradiscal electrothermal therapy (IDET) is a minimally invasive treatment option for patients with symptomatic internal disc disruption nonresponsive to conservative medical care.

METHODS

Using MRI and discographic findings, 50 patients with lumbar discogenic pain were identified, underwent IDET treatment and were followed for 24 months. Outcomes included assessments of back pain severity by an 11-point numeric scale and back function by the Oswestry disability index (ODI).

FINDINGS

There was an average 68 and 66% improvement in pain and ODI, respectively, between pre-treatment and 24 months (p < 0.0001 for both comparisons). The global clinical success rate was 78% (39 of 50). Clinical success was associated with discographic concordance (p < 0.0001), HIZ (p = 0.003), Pfirrmann grade (p = 0.0002), and percent annulus coverage (p < 0.0001).

CONCLUSIONS

The findings of this study suggest that durable clinical improvements can be realized after IDET in highly selected patients with mild disc degeneration, confirmatory imaging evidence of annular disruption and concordant pain provocation by low pressure discography.

Spinal manipulation or mobilization for radiculopathy: a systematic review

In this systematic review, we present a comprehensive and up-to-date systematic review of the literature as it relates to the efficacy and effectiveness of spinal manipulation or mobilization in the management of cervical, thoracic, and lumbar-related extremity pain. There is moderate quality evidence that spinal manipulation is effective for the treatment of acute lumbar radiculopathy. The quality of evidence for chronic lumbar spine-related extremity symptoms and cervical spine-related extremity symptoms of any duration is low or very low. At present, no evidence exists for the treatment of thoracic radiculopathy. Future high-quality studies should address these conditions.

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.

Regeneration potential and mechanism of bone marrow mesenchymal stem cell transplantation for treating intervertebral disc degeneration

Intervertebral disc degeneration is a primary cause of low back pain and has a high societal cost. The pathological mechanism by which the intervertebral disc degenerates is largely unknown. Cell-based therapy especially using bone marrow mesenchymal stem cells as seeds for transplantation, although still in its infancy, is proving to be a promising, realistic approach to intervertebral disc regeneration. This article reviews current advances regarding regeneration potential in both the in vivo and vitro studies of bone marrow mesenchymal stem cell-based therapy and discusses the up-to-date regeneration mechanisms of stem cell transplantation for treating intervertebral disc degeneration.

Effectiveness of L2 spinal nerve infiltration for selective discogenic low back pain patients

BACKGROUND

It has been reported that rat L5/6 lumbar discs are innervated mainly by L2 dorsal root ganglion neurons. We previously reported that L2 spinal nerve infiltration was effective for discogenic low back pain (DLBP) patients, although the diagnosis was based only on the results of physical examination, plain films, and magnetic resonance imaging (MRI). The purpose of the current study was to evaluate L2 spinal nerve block for DLBP patients retrospectively based on MRI findings and surgical results.

METHODS

A total of 62 patients with only LBP and no accompanying radicular pain were investigated. Patients had only one level of disc degeneration on MRI. When pain was provoked during discography, we performed surgery at the next stage (40 patients). In all, 22 patients were excluded owing to negative discography results. Of the 40 patients, we evaluated 25 strictly selected patients suffering from DLBP. DLBP was diagnosed when the patient experienced pain relief at least 2 years after anterior lumbar interbody fusion. Fifteen patients who did not show pain relief after surgery were used for the non-DLBP group. L2 spinal nerve infiltration using 1.5 ml of lidocaine was performed in all 40 patients before surgery. The visual analogue scale (VAS) score after L2 spinal nerve infiltration was recorded, and an association of L2 spinal nerve infiltration and DLBP was explored.

RESULTS

Low back pain scores assessed using the VAS score, the Japanese Orthopedic Association score, and the Oswestry Disability Index score in the two groups were not significantly different. L 2 spinal nerve infiltration was effective for 27 patients but not effective for 13 patients; the VAS score after 15 min and 2 h improved in the DLBP group compared with that of the non-DLBP group (P < 0. 05). L2 spinal nerve infiltration was more effective in DLBP patients (21 patients, 84%) than in the non-DLBP group (6 patients, 40%) (P < 0.05).

CONCLUSIONS

In the current study, L2 spinal nerve infiltration was effective in 84% of selected DLBP patients and is thought to be a useful tool for diagnosing DLBP. However, we should take into consideration that the L2 spinal nerve infiltration was effective in 40% of non-DLBP patients as well.

[Neurostimulation techniques in the therapeutic management of chronic pelvic and perineal pain]

INTRODUCTION

Neuromodulation is a nonspecific analgesic treatment whose mechanism of action has not yet been elucidated. The purpose of this article is to review the techniques and results of neuromodulation in the management of chronic pelvic and perineal pain.

MATERIAL AND METHODS

A comprehensive review of the literature was performed by searching PUBMED for articles on the various neuromodulation techniques used in the management of chronic pelvic and perineal pain.

RESULTS

Several levels of neuromodulation of the somatic nervous system have been evaluated in the management of pelvic pain: transcutaneous electrical nerve stimulation (TENS), percutaneous nerve stimulation (PNS), nerve root or nerve trunk stimulation, spinal cord stimulation. An improvement was obtained in an average of two thirds of cases, but with declining efficacy over time. The various studies were difficult to compare due to the heterogeneous study populations and very diverse endpoints. Interesting studies on the value of autonomic nervous system intervention have been described, but with no specific trials of neuromodulation.

CONCLUSION

The place of neuromodulation in the management of patients with chronic pelvic and perineal pain has yet to be defined, as it is too frequently used as a last resort. It appears important to develop and analyse this treatment modality in large-scale, randomized, prospective studies.

ISSLS prize winner: a study of effects of in vivo mechanical forces on human lumbar discs with scoliotic disc as a biological model: results from serial postcontrast diffusion studies, histopathology and biochemical analysis of twenty-one human lumbar scoliotic discs

STUDY DESIGN

A comprehensive study of 21 lumbar scoliotic discs by in vivo serial post contrast diffusion magnetic resonance imaging (MRI), histopathological, and biochemical analysis.

OBJECTIVE

To investigate the in vivo effects of compressive and tensile mechanical stress on the lumbar discs with scoliotic disc as the biologic model.

SUMMARY OF BACKGROUND DATA

Most studies implicating mechanical stress in degenerative disc disease (DDD) are on animals, in vitro conditions and cadavers. They are also restricted to histopathological or biochemical evaluation without analyzing the endplate (EP) and nucleus pulposus (NP) separately. The few human studies have not analyzed diffusion changes which is the final pathway for DDD. Adolescent scoliotic disc offer a perfect model to study the effects of mechanical stress.

METHODS

Twenty-one discs from 6 patients with adolescent idiopathic scoliosis undergoing anterior corrective surgery were assessed before surgery by postcontrast MRI to document the EP diffusion patterns. The same discs harvested during surgery were analyzed histologically and biochemically. The results were correlated to clinical and radiologic parameters.

RESULTS

Altered diffusion patterns was seen in all discs with site specific breaks in 2, double peak pattern in 3, high intensity pattern in 14, and frank contrast leak in 2. There was marked decrease in cell density and viability in all discs on both convex and concave sides compared to the control disc (P = 0.001). Neovascularization, calcification, and matrix degeneration were observed to varying extent in different regions of NP and EP. There was a decrease in water content with increasing severity of curves with significant difference between mild and severe curves (NP: P = 0.000, EP: P = 0.002). Lactate was significantly higher in caudal EP (P = 0.035) and discs with coronal migration of more than 15 mm (P = 0.007). Regression analysis showed that truncal decompensation was a main factor for decrease in cell density, matrix degeneration, calcification, and water content.

CONCLUSION

The study documents widespread changes in the EP and NP even in discs with minimal wedging. EP damage and alterations in diffusion were observed earlier than MRI changes and could indicate nutritional factors as the primary mechanism of degeneration induced by mechanical stress. Degeneration was more severe in caudal discs and those with truncal decompensation. Its implications on the timing and choice of surgery in scoliosis are discussed.

ISSLS prize winner: prevalence, determinants, and association of Schmorl nodes of the lumbar spine with disc degeneration: a population-based study of 2449 individuals

STUDY DESIGN

A cross-sectional population-based magnetic resonance imaging study of Schmorl nodes (SN) in the lumbar spine.

OBJECTIVE

To determine the prevalence and potential determinants of SN, and their association with intervertebral disc degeneration.

SUMMARY OF BACKGROUND DATA

SN represent intravertebral disc herniation and are commonly seen in the spine. Their reported prevalence and determinants vary, and their association with disc degeneration remains uncertain. Data based on this large scale population-based study of intervertebral disc degeneration would provide important information for understanding SN and their pathomechanism.

METHODS

Sagittal T2-weighted magnetic resonance imagings of the lumbar spine were analyzed in 2449 volunteers. Two independent observers assessed the images for the presence of SN, and scored for additional radiologic features (e.g., severity of degeneration, presence of disc bulge/extrusion). Subject demographics were assessed by standardized questionnaire.

RESULTS

SN were found in 16.4% (n = 401; 219 males, 182 females; mean age = 42.3) of our study population (981 males, 1468 females; mean age = 40.4), being most common at L1/2 and L2/3 (54.1%). Multivariate logistic regression revealed that males, taller and heavier individuals had an increased likelihood of SN (P < 0.005), but association between SN and age were not discerned. Overall presence of SN was associated with disc degeneration (P < 0.001), and linearly correlated (R = 0.97) with increase in severity of degeneration. SN were particularly associated with severe disc degeneration at L1/2 and L2/3 with 22- to 15-fold increased odds, respectively (P < 0.0001), but less than 5-fold increased odds (P < 0.001) were noted in the lower lumbar spine.

CONCLUSION

In a population-based cohort, 16.4% of Southern Chinese subjects had SN at 1 or more lumbar levels. Males, taller and heavier individuals had increased likelihood of SN. Interestingly, SN were highly associated with severity of disc degeneration.

Notochordal cells influence gene expression of inflammatory mediators of annulus fibrosus cells in proinflammatory cytokines stimulation

OBJECTIVE

Notochordal cells in the intervertebral disc interact with nucleus pulposus (NP) cells and support the maintenance of disc homeostasis by regulation of matrix production. However, the influence of notochordal cells has not been evaluated in the annulus fibrosus (AF), which is the primary pain generator in the disc. We hypothesized that the notochordal cell has the capacity to modulate inflammatory mediators secreted by AF cells secondary to stimulation.

METHODS

Notochordal and AF cells were isolated from adult New Zealand white rabbits. AF pellets were cultured with notochordal cell clusters or in notochordal cell-conditioned media (NCCM) for 24 or 48 hours with proinflammatory cytokines at varying concentrations. Gene expression in AF pellets were assayed for nitric oxide synthase (iNOS), cyclo-oxygenase (COX)-2, and interleukin (IL)-6 by real time reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

AF pellet in NCCM significantly decreased the iNOS and COX-2 messenger ribonucleic acid (mRNA) levels compared to AF pellets alone and AF pellets with notochordal cells (p < 0.05). AF pellet resulted in dose-dependent iNOS and COX-2 expression in response to IL-1beta, stimulation, demonstrating that 1 ng/ml for 24 hours yielded a maximal response. AF pellet in NCCM significantly decreased the expression of iNOS and COX-2 in response to 1ng/ml IL-1beta, stimulation at 24 hours (p < 0.05). There was no difference in IL-6 expression compared to AF pellets alone or AF pellets with notochordal cell clusters.

CONCLUSION

We conclude that soluble factors from notochordal cells mitigate the gene expression of inflammatory mediators in stimulated AF, as expected after annular injury, suggesting that notochordal cells could serve as a novel therapeutic approach in symptomatic disc development.

Regulation of CCN2/connective tissue growth factor expression in the nucleus pulposus of the intervertebral disc: role of Smad and activator protein 1 signaling

OBJECTIVE

To investigate transforming growth factor beta (TGFbeta) regulation of connective tissue growth factor (CTGF) expression in cells of the nucleus pulposus of rats, mice, and humans.

METHODS

Real-time reverse transcription-polymerase chain reaction and Western blot analyses were used to measure CTGF expression in the nucleus pulposus. Transfections were used to measure the effects of Smads 2, 3, and 7 and activator protein 1 (AP-1) on TGFbeta-mediated CTGF promoter activity.

RESULTS

CTGF expression was lower in neonatal rat discs than in skeletally mature rat discs. An increase in CTGF expression and promoter activity was observed in rat nucleus pulposus cells after TGFbeta treatment. Deletion analysis indicated that promoter constructs lacking Smad and AP-1 motifs were unresponsive to treatment. Analysis showed that full-length Smad3 and the Smad3 MH-2 domain alone increased CTGF activity. Further evidence of Smad3 and AP-1 involvement was seen when DN-Smad3, SiRNA-Smad3, Smad7, and DN-AP-1 suppressed TGFbeta-mediated activation of the CTGF promoter. When either Smad3 or AP-1 sites were mutated, CTGF promoter induction by TGFbeta was suppressed. We also observed a decrease in the expression of CTGF in discs from Smad3-null mice as compared with those from wild-type mice. Analysis of human nucleus pulposus samples indicated a trend toward increasing CTGF and TGFbeta expression in the degenerated state.

CONCLUSION

TGFbeta, through Smad3 and AP-1, serves as a positive regulator of CTGF expression in the nucleus pulposus. We propose that CTGF is a part of the limited reparative response of the degenerated disc.

Lumbar intervertebral disc abnormalities: comparison of quantitative T2 mapping with conventional MR at 3.0 T

OBJECTIVE

To assess the relationship of morphologically defined lumbar disc abnormalities with quantitative T2 mapping.

METHODS

Fifty-three patients, mean age 39 years, with low back pain were examined by MRI at 3 T (sagittal T1-fast spin echo (FSE), three-plane T2-FSE for morphological MRI, multi-echo spin echo for T2 mapping). All discs were classified morphologically. Regions of interest (ROIs) for the annulus were drawn. The space in between was defined as the nucleus pulposus (NP). To evaluate differences between the classified groups, univariate ANOVA with post hoc Games-Howell and paired two-tailed t tests were used.

RESULTS

In 265 discs we found 39 focal herniations, 10 annular tears, 123 bulging discs and 103 "normal discs". T2 values of the NP between discs with annular tear and all other groups were statistically significantly different (all p ≤ 0.01). Discs with annular tears showed markedly lower NP T2 values than discs without. The difference in NP T2 values between discs with focal herniation and normal discs (p = 0.005) was statistically significant. There was no difference in NP T2 values between bulging and herniated discs (p = 0.11)

CONCLUSION

Quantitative T2 mapping of the nucleus pulposus of the intervertebral disc in the lumbar spine at 3 T reveals significant differences in discs with herniation and annular tears compared with discs without these abnormalities.

Percutaneous laser disc decompression for thoracic disc disease: report of 10 cases

BACKGROUND

Discogenic pain or herniation causing neural impingement of the thoracic vertebrae is less common than that in the cervical or lumbar regions. Treatment of thoracic discogenic pain usually involves conservative measures. If this fails, conventional fusion or discectomy can be considered, but these procedures carry significant risk.

OBJECTIVES

To assess the efficacy and safety of percutaneous laser disc decompression (PLDD) for the treatment of thoracic disc disease.

METHODS

Ten patients with thoracic discogenic pain who were unresponsive to conservative intervention underwent the PLDD procedure. Thoracic pain was assessed using the Visual Analog Scale (VAS) scores preoperatively and at 6-month intervals with a minimum of 18-months follow-up. Patients were diagnosed and chosen for enrollment based on abnormal MRI findings and positive provocative discograms. Patients with gross herniations were not included.

RESULTS

Length of follow-up ranged from 18 to 31 months (mean: 24.2 mo). Median pretreatment thoracic VAS score was 8.5 (range: 5-10) and median VAS score at final follow-up was 3.8 (range: 0-9). Postoperative improvement was significant with a 99% confidence interval. Of interest, patients generally fell into two groups, those with significant pain reduction and those with little to no improvement. Although complications such as pneumothorax, discitis, or nerve damage were possible, no adverse events occurred during the procedures.

LIMITATIONS

The study is limited by its small size and lack of a sham group. Larger controlled studies are warranted.

CONCLUSIONS

With further clinical evidence, PLDD could be considered a viable option with a low risk of complication for the treatment of thoracic discogenic pain that does not resolve with conservative treatment.

Use of Temporary Implantable Biomaterials to Reduce Leg Pain and Back Pain in Patients with Sciatica and Lumbar Disc Herniation

The principle etiology of leg pain (sciatica) from lumbar disc herniation is mechanical compression of the nerve root. Sciatica is reduced by decompression of the herniated disc, i.e., removing mechanical compression of the nerve root. Decompression surgery typically reduces sciatica more than lumbar back pain (LBP). Decompression surgery reduces mechanical compression of the nerve root. However, decompression surgery does not directly reduce sensitization of the sensory nerves in the epidural space and disc. In addition, sensory nerves in the annulus fibrosus and epidural space are not protected from topical interaction with pain mediators induced by decompression surgery. The secondary etiology of sciatica from lumbar disc herniation is sensitization of the nerve root. Sensitization of the nerve root results from a) mechanical compression, b) exposure to cellular pain mediators, and/or c) exposure to biochemical pain mediators. Although decompression surgery reduces nerve root compression, sensory nerve sensitization often persists. These observations are consistent with continued exposure of tissue in the epidural space, including the nerve root, to increased cellular and biochemical pain mediators following surgery. A potential contributor to lumbar back pain (LBP) is stimulation of sensory nerves in the annulus fibrosus by a) cellular pain mediators and/or b) biochemical pain mediators that accompany annular tears or disruption. Sensory fibers located in the outer one-third of the annulus fibrosus increase in number and depth as a result of disc herniation. The nucleus pulposus is comprised of material that can produce an autoimmune stimulation of the sensory nerves located in the annulus and epidural space leading to LBP. The sensory nerves of the annulus fibrosus and epidural space may be sensitized by topical exposure to cellular and biochemical pain mediators induced by lumbar surgery. Annulotomy or annular rupture allows the nucleus pulposus topical access to sensory nerve fibers, thereby leading to LBP. Coverage of the annulus and adjacent structures in the epidural space by absorbable viscoelastic gels appears to reduce LBP following surgery by protecting sensory fibers from cellular and biochemical pain mediators.