K. Yamauchi

Intradiscal Administration of Tumor Necrosis Factor-α Inhibitor, Etanercept, Clinically Improves Intractable Discogenic Low Back Pain

Introduction Discogenic low back pain (LBP) has been clinically considered to be one of the sources of intractable LBP. Tumor necrosis factor-α (TNF-α) is one of the well-known pain-related proinflammatory mediators in the degenerative intervertebral disc. However, it is unclear whether its inhibition leads to any analgesic outcomes. In this study, we aimed to examine the effect of intradiscal TNF-α inhibitor administration in discogenic LBP patients. Materials and Methods Discogenic LBP patients were diagnosed on the basis of physical and radiographic (X-ray and magnetic resonance imaging) findings. Sixty patients were divided randomly into two groups: etanercept group (n = 30; bupivacaine 2 mL with etanercept 10 mg) and control group (n = 30; bupivacaine 2 mL). Numerical rating scale score for LBP before and 1 day, 1, 2, and 4 weeks after the injection and Oswestry disability index (ODI) score before and 4 weeks after the injection were evaluated. In addition, complications after the injection were evaluated. Results While both groups experienced considerable pain relief, the visual analog scale score significantly decreased in the etanercept group at every time point after the injection (p < 0.05). The ODI score decreased 4 weeks after the injection only in the etanercept group (p < 0.05). There were no complications in either group. Conclusion Single intradiscal administration of TNF-α inhibitor showed a greater analgesic effect without any complications lasting for 4 weeks, thereby implying that TNF-α may be profoundly involved in the pathogenesis of chronic discogenic LBP. The present study indicates that intradiscal administration of TNF-α inhibitor can be useful for intractable discogenic LBP treatment in humans. Disclosure of Interest None declared

Does Site of Symptoms Influence the Surgical Results for Discogenic Low Back Pain Treatment

Introduction Surgical results for discogenic low back pain (DLBP) treatment remain controversial. The method of diagnosis of DLBP generally used is MRI and discography. However, this imaging sometime fails to diagnose DLBP. Symptoms from DLBP are varied and include back pain alone, referred leg pain, and referred inguinal pain. In the current study, we aimed to evaluate whether the site of symptoms influences surgical results for DLBP treatment. Materials and Methods The site of symptoms before surgery and the surgical result were retrospectively evaluated in 62 DLBP patients. Symptom sites before surgery were divided into (1) back pain alone, (2) back pain + referred inguinal pain, (3) back pain + referred thigh pain, and (4) back pain + referred lower leg pain. The patients showed disc degeneration only at one level (L4-5 or L5-S1) on MRI, pain provocation on discography, and underwent anterior interbody fusion. Visual analog scale (VAS) of back pain and the Roland-Morris disability questionnaire (RDQ) were evaluated before and 2 years after surgery. Results VAS and RDQ were not significantly different between the four groups before surgery, but were significantly improved in all four groups 2 years after surgery (p < 0.05). The greatest improvement of back pain was found in the group with back pain + referred inguinal pain compared with the other three groups (p < 0.05). Less improvement of back pain in the back pain alone group was seen compared with the back pain + referred thigh and back pain + referred lower leg pain groups (p < 0.05). Conclusion If DLBP is strictly diagnosed using several imaging modes, surgical results were superior in patients with both back pain and either referred inguinal or leg pain compared with those having back pain alone. Disclosure of Interest None declared

Basic Research on Neuronal Activation Induced by Intradiscal Pain Stimulation into Degenerative ?Intervertebral Disc Using Capsaicin

Introduction Previously, it was reported that pain perception is related to not only DRG but also to the reaction of the central nervous system; however, the reaction of the dominant nervous system to pain stimulus in the intervertebral discs is unknown. The purpose of this research was to verify the mechanism of reaction of the nervous system, which controls the intervertebral discs, using chemical pain stimulus. Materials and Methods We used 6-week-old Sprague Dawley rats, and injected 20 µL capsaicin solution, which contains 2% Fluoro-Gold (FG), into the L5/6 intervertebral disc. FG is an antidromic neuronal tracer. Seven days after injection, we prepared perfusion fixation of the rats and extracted DRGs from L1 to L6 along with the lumbar enlargement of spinal cord. At the DRG, we detected CGRP, which is a nociceptive pain-related protein, by immunostaining, and measured the distribution of the expression. At the lumbar enlargement of the spinal cord, we detected Iba1, which is a marker for pain stimulus-activated micro glia, and compared Iba 1 expression in the capsaicin group and vehicle group, in which we injected only 20 µL saline solution (each is n = 5). Results The rate of distribution of CGRP positive cells in the FG positive rats was highest at the L2 DRG, and the rate was higher in the capsaicin group (54.9%) than in vehicle group (27.1%), with a statistically significant difference (p < 0.05). The number of Iba1 positive micro glia cells per 1.4 × 10 mm2 was also larger in the capsaicin group (31.7 cells) than in the vehicle group (14.8 cells), with a statically significant difference (p < 0.05) Conclusion The results of this experiment suggested that the chemical stimulus to the L5/6 intervertebral disc resulted in an elevated CGRP expression that caused pain around the L2 DRG area, and the mechanism of pain perception is strongly related to the activation of microglia at the posterior horn of the spinal cord. Disclosure of Interest None declared

A Randomized Controlled Trial of Lumbar Posterolateral Fusion in Combination with Platelet-Rich Plasma

Introduction Platelet-rich plasma (PRP) has been reported to be a source of autologous growth factors (PDGF and TGF-β) that enhance bone formation. However, PRP has failed to improve fusion rates, perhaps due to suboptimal levels of growth factors. We began a Phase 1 study in July 2009, the purposes of which were to produce highly concentrated PRP enriched in growth factors, to monitor side effects, and to determine subsequent fusion rates. This is the first randomized controlled trial to investigate the potential advantages of using PRP in posterolateral fusion. Platelet-rich plasma (PRP) has been reported to be a source of autologous growth factors (PDGF and TGF-β) that enhance bone formation. However, PRP has failed to improve fusion rates, perhaps due to suboptimal levels of growth factors. We began a Phase 1 study in July 2009, the purposes of which were to produce highly concentrated PRP enriched in growth factors, to monitor side effects, and to determine subsequent fusion rates. This is the first randomized controlled trial to investigate the potential advantages of using PRP in posterolateral fusion. Materials and Methods Thirty-nine patients diagnosed with spinal canal stenosis were divided equally into “PRP” and “control” groups. The PRP patients underwent posterolateral fusion with instrumentation using autograft bone plus PRP, while control patients underwent the same procedure minus PRP. In the PRP group, one unit of whole blood (400 mL) was drawn from each patient at the beginning of surgery and centrifuged to extract platelets. Twenty mL of PRP was obtained, to which thrombin and CaCl2 were added to form a platelet gel for application to the surgical field. Bone fusion was periodically assessed using X-ray and CT. Results The average platelet concentration was 7.7-fold higher in the PRP than plasma. Growth factors released from the platelet gel were more than 50-fold concentrated compared with blood levels. No significant adverse events were observed. Bone union was observed in all patients. The average period was 7.8 months in the PRP group, and 9.8 months in the control group. The average platelet concentration was 7.7-fold higher in the PRP than plasma. Growth factors released from the platelet gel were more than 50-fold concentrated compared with blood levels. No significant adverse events were observed. Bone union was observed in all patients. The average period was 7.8 months in the PRP group, and 9.8 months in the control group. Conclusion In the present study, bone union was achieved more rapidly in the PRP group, which suggests that enhanced bone formation was achieved by providing an elevated concentration of PRP. However, further research is required. In the present study, bone union was achieved more rapidly in the PRP group, which suggests that enhanced bone formation was achieved by providing an elevated concentration of PRP. However, further research is required. Disclosure of Interest None declared

Diffusion Tensor Imaging for Quantitative Evaluation of Lumbar Intervertebral Disc Degeneration

Introduction Pfirrmann classification, T2- and T1ρ mapping using MRI are tools to evaluate intervertebral disc (IVD) degeneration. Diffusion tensor imaging (DTI) and diffuion tensor tractography (DTT) are neuroimaging tools for visualizing highly anisotropic tissues. Recently, DTI is used for evaluation of degenerated IVDs. The purpose of this study is to provide evidence for the efficacy of DTI and DTT in the quantitative evaluation of degenerated IVDs. Materials and Methods Three patients with discogenic low back pain underwent DTI and DTT on a 3.0 T MR scanner. We evaluated 12 discs from L2-3 to L5-S in each patient. Pfirrmann classification on conventional MR imaging, fractional anisotropy (FA) value, morphological classification on DTT, and number of tracking fibers were evaluated. IVD was divided into three layers in a concentric manner from the center; FA value was measured at each layer. DTT was classified into ring, donut, and disk type. Results With Pfirrmann classifications, six, two, and four discs were grades 2, 3, and 4, respectively. With DTT classification, six, one, and five discs were ring, donut, and disk types, respectively. All grades 2,1, and3 discs corresponded to ring type, and all grade 4 and the other grade 3 discs corresponded to disk type. FA value of the intermediate layer was 0.10 for ring type, 0.21 for donut, and 0.23 for disk type. FA value of the inner layer was 0.06 for ring type, 0.09 for donut, and 0.20 for disk type. The number of tracking fibers was increased in disk types. Conclusion This study showed that shape on DTT correlated to Pfirrmann classification, and DTT of discs can describe the IVD degeneration process. A previous study showed that water content tended to decrease in IVD degeneration. The increasing FA value and number of the tracking fibers may reflect a decreased water content and tissue degeneration. Thus, DTI and DTT can visualize and quantitatively evaluate IVD degeneration. DTI and DTT may detect degeneration and evaluate repair and regeneration. Disclosure of Interest None declared

Evaluation of the Correlation among the Expression of Inflammatory Cytokines, Degeneration of the Intervertebral Disc, and Prominent Symptoms in Degenerative Human Lumbar Intervertebral Discs

Introduction Low back pain (LBP) disease is reportedly associated with inflammatory cytokines such as tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), as well as with nerve growth factor (NGF) that is expressed in increased amounts within degenerative intervertebral discs (IVDs). In the present study, we aimed to assess the correlation between the local expression of TNF-α, IL-6, and NGF within degenerative human lumbar IVDs and the degree of degeneration, as well as the correlation between the expression of these mediators and the prominent symptoms. Materials and Methods In total, 58 IVD samples of patients who underwent surgery for various lumbar disorders were examined. The expression level of these mediators in each sample was determined using enzyme-linked immunosorbent assay. The samples were grouped according to the degree of IVD degeneration using Pfirrmann grading on magnetic resonance imaging, and the grades were correlated with the individual expression levels. The chief complaints of the patients were then recorded and assigned to the LBP group and the leg pain group, and were compared with the individual expression levels. Results A gradual increase in TNF-α (R: 0.391) and IL-6 (R: 0.388) expression levels were observed with a progression in the degree of degeneration, but NGF (R: − 0.164) exhibited a minimal decrease in the expression level. With regard to the chief complaints, the LBP group only exhibited a significant increase in the TNF-α expression level. Conclusion We noted a trend of increasing expression levels of TNF-α and IL-6 with the progression of IVD degeneration, which indicates that these cytokines may have an important role in the degenerative process of IVD at any stage. Moreover, NGF may have an important effect during the early stage of the progression of degeneration. With regard to the symptoms, TNF-α expression was significantly greater in the LBP group. Thus, we propose that TNF-α may be significantly involved in LBP. Disclosure of Interest None declared

Low Affinity NGF Receptor (p75 Neurotrophin Receptor) Inhibit Sensory Nerve Growth in Human Degenerative Nucleus Pulposus Cells

Introduction Degeneration of the lumbar intervertebral disc is a cause of low back pain. The pathological mechanism is thought to be sensory nerve ingrowth into the inner layers of the degenerated intervertebral disc. NGF is also important for mediating inflammatory pain from intervertebral discs via the high-affinity receptor, TrkA. Recent research has also revealed that the low-affinity NGF receptor, p75 neurotrophic receptor (p75NTR), plays an important role in inflammatory pain. In most DRG neurons, innervating rat intervertebral discs were positive for two types of NGF receptors. However, the participative two types of NGF receptors have not been clarified in human degenerative discs. To evaluate the axonal growth and induction of a painful neuropeptide, CGRP, using neutralize antibody and extracted medium from human degenerative disc cells in vitro. Materials and Methods The nucleus pulposus (NP) of human intervertebral discs were harvested from patients with discogenic low back pain. Extracted medium from human degenerative intervertebral discs and rat DRGs were cultured with TrkA or p75NTR neutralize antibody. We evaluated the promotion of axonal growth and CGRP induction of DRG neurons in extracted medium from the NP using immunocytochemistry. Results The average length of growing axons in the NP and positive control group with TrkA or p75NTR neutralize antibody were significantly longer than that in the control group (p < 0.001). The average length of growing axons in the NP group and positive control group was significantly shortened after TrkA and p75NTR neutralize antibody treatment (p < 0.001). The percentage of CGRP-immunoreactive cells with growing axons was significantly shorter than in the NP and positive control group compared with the control groups with p75NTR neutralize antibody (p < 0.05). The expression of CGRP in all group with TrkA neutralize antibody was not decreased. Conclusion TrkA and p75NTR were associated with the growing axons in extracted medium from the NP of human intervertebral discs. p75NTR were associated with the percentage of CGRP-immunoreactive cells with growing axons more than TrkA. These in vitro results may suggest that p75NTR is related with discogenic low back pain. Disclosure of Interest None declared References Yamauchi K, Inoue G, Koshi T, et al. Nerve growth factor of cultured medium extracted from human degenerative nucleus pulposus promotes sensory nerve growth and induces substance p in vitro. Spine 2009;34(21):2263–2269 Sugiura A, Ohtori S, Yamashita M, et al. Effect of applying p75NTR saporin to a punctured intervertebral disc on calcitonin gene-related peptide expression in rat dorsal root ganglion neurons. J Orthop Sci 2010;15(3):407–413 Fukui Y, Ohtori S, Yamashita M, et al. Low affinity NGF receptor (p75 neurotrophin receptor) inhibitory antibody reduces pain behavior and CGRP expression in DRG in the mouse sciatic nerve crush model. J Orthop Res 2010;28(3):279–283

Classification of Chronic Back Muscle Degeneration after Spinal Surgery, and Its Relationship to Low Back Pain

Introduction Back muscle injury and degeneration often occurs after posterior lumbar surgery, and back muscle degeneration may be a cause of back pain after surgery. However, the relationship between back muscle degeneration and back pain remains controversial. In the current study, we aimed to classify back muscle degeneration using MRI and investigate its relationship with back pain after surgery. Materials and Methods A total of 84 patients (average age: 65.1 years, 38 men, 46 women) with lumbar spinal stenosis underwent only posterior decompression surgery. MRI (1.5 T) was evaluated before and more than a year after surgery in all patients. Muscle on MRI was classified into three categories: low intensity in T1-weighted image, high in T2-weighted image (type 1), high in both T1- and T2-weighted images (type 2), and low in both T1- and T2-weighted images (type 3). The proportion of types and their relationship with back pain (visual analog scale: VAS) was evaluated. Results MRI revealed muscle degeneration in all patients after surgery (type 1: 6%, type 2: 82%, and type 3: 12%). Type 2 was significantly frequent as compared with types 1 and 3 (p < 0.01). Low back pain before surgery (average: VAS 7.5) significantly improved after surgery (average: VAS 2.0) (p < 0.01). Low back pain was not associated with any muscle degeneration MRI types after surgery (p > 0.05). Conclusion The current study showed the pathology of back muscle degeneration was various after posterior lumbar surgery. Type 2 (fatty change) was most frequent, and some patients were classified into type 3 (scar change), and type 1 (inflammation or water-like change). Modic classification is used for bone marrow change, and type 1 is associated with inflammation and back pain. However, no type of back muscle degeneration was correlated with back pain after surgery. Disclosure of Interest None declared

Comparison between Anterior Lumbar Interbody Fusion and Posterolateral Fusion in a Punctured Disk Model in Rats

Introduction Conservative treatments are sufficient for patients with discogenic pain; however, fusion surgery is performed to relieve unresolved pain. Of several available fusion techniques, the method remains controversial. This study used pain assessment to compare anterior lumbar interbody fusion (ALIF) versus posterolateral fusion (PLF) in a rat-punctured disk model. Materials and Methods Total 80 male Sprague-Dawley rats (200 to 250 g) were divided into four groups, nonpuncture group(n = 20), puncture group(n = 20), puncture + ALIF group(n = 20), and puncture + PLF group(n = 20). The neurotracer fluoro-gold was applied to detect dorsal root ganglion (DRG) neuron disk innervation. After 1 week of the procedure, surgical treatment was performed in ALIF and PLF groups. After 4 and 8 weeks of surgery, bone union was verified using micro CT, pain behavior was analyzed using CatWalk system, and the proportion of calcitonin gene-related peptide (CGRP) (pain neuropeptide)-immunoreactive, FG-labeled DRG neurons were determined. Results Bone union was confirmed at 4 and 8 weeks in both fusion groups. In CatWalk analysis, ALIF animals significantly improved over 8 weeks compared to PLF animals (p < 0.05). CGRP-immunoreactive DRG neurons increased in all puncture groups compared to nonpuncture group (p < 0.01); however, these decreased in the fusion groups to control levels at 8 weeks, and the significant difference between ALIF and PLF animals was observed only at 2 weeks (p < 0.05). Conclusion After completion of bone union, punctured disk-related pain decreased to control levels in both fusion groups; however, ALIF animals showed faster recovery of pain behavior than PLF animals. These results suggest that both ALIF and PLF are similarly effective for pain originated from degenerated disks, but posterior muscle injury might influence postoperative healing. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared

Inhibiting Brain-Derived Neurotrophic Factor (Bdnf) at the Punctured Intervertebral Disk Downregulates Pain-Related Neuropeptide Production in Dorsal Root Ganglia in Rats

Introduction BDNF-a neurotrophin in dorsal root ganglion (DRG) neurons-is known to be anterogradely transported to the spinal cord and transmits pain signals existing in the central nervous system. A previous study has recently reported its presence in the peripheral sites of degenerative IVDs, although its association with discogenic pain remains unclear. The present study aimed to investigate the association between BDNF and pain-related sensory innervation of multiple-punctured lumbar IVD in rats. Materials and Methods Forty female Sprague-Dawley rats were equally divided into four groups: naïve, sham, and two agent-treated groups (vehicle (saline-treated) and anti-BDNF (anti-BDNF antibody) group). L5-6 IVDs of the agent-treated rats were exposed and injured by repeated punctures. The retrograde neurotracer Fluoro-Gold (FG) and treatment agents were intradiscally applied. In the sham group, FG alone was applied onto uninjured IVD. One week later, L1-3 DRGs were harvested and immunolabeled for the inflammatory pain-related calcitonin gene-related peptide (CGRP), that is, the pain marker. The proportions of FG-labeled CGRP-immunoreactive (-ir) DRG neurons were assessed. BDNF concentration of each L5-6 IVD was measured using enzyme-linked immunosorbent assay (ELISA). Results FG-labeled DRG neurons were almost equally prevalent at each DRG level. The proportions of FG-labeled CGRP-ir DRG neurons in the two agent-treated groups were significantly elevated (p < 0.05) compared with the naïve and sham groups and were significantly decreased in the anti-BDNF group as compared to the vehicle group (p < 0.05). BDNF concentrations were elevated maximally in the vehicle group but suppressed in the anti-BDNF group. Conclusion Direct intradiscal application of the anti-BDNF antibody significantly suppressed both CGRP production and the local concentration of BDNF. Our results indicate a possible association between the local production of BDNF and the pathophysiology of discogenic pain. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared