Study DesignPreliminary clinical trial.PurposeTo determine the safety and initial efficacy of intradiscal injection of autologous platelet-rich plasma (PRP) releasate in patients with discogenic low back pain.Overview of LiteraturePRP, which is comprised of autologous growth factors and cytokines, has been widely used in the clinical setting for tissue regeneration and repair. PRP has been shown in vitro and in vivo to potentially stimulate intervertebral disc matrix metabolism.MethodsInclusion criteria for this study included chronic low back pain without leg pain for more than 3 months; one or more lumbar discs (L3/L4 to L5/S1) with evidence of degeneration, as indicated via magnetic resonance imaging (MRI); and at least one symptomatic disc, confirmed using standardized provocative discography. PRP releasate, isolated from clotted PRP, was injected into the center of the nucleus pulposus. Outcome measures included the use of a visual analog scale (VAS) and the Roland-Morris Disability Questionnaire (RDQ), as well as X-ray and MRI (T2-quantification).ResultsData were analyzed from 14 patients (8 men and 6 women; mean age, 33.8 years). The average follow-up period was 10 months. Following treatment, no patient experienced adverse events or significant narrowing of disc height. The mean pain scores before treatment (VAS, 7.5±1.3; RDQ, 12.6±4.1) were significantly decreased at one month, and this was generally sustained throughout the observation period (6 months after treatment: VAS, 3.2±2.4, RDQ; 3.6±4.5 and 12 months: VAS, 2.9±2.8; RDQ, 2.8±3.9; p<0.01, respectively). The mean T2 values did not significantly change after treatment.ConclusionsWe demonstrated that intradiscal injection of autologous PRP releasate in patients with low back pain was safe, with no adverse events observed during follow-up. Future randomized controlled clinical studies should be performed to systematically evaluate the effects of this therapy.

BackgroundThe progression of intervertebral disc (IVD) degeneration leads to rupture within IVD tissues. The location and appearance of areas of gaseous radiolucency in the IVD, known as vacuum phenomena (VPs), are considered to indirectly indicate the position and extent of IVD rupture. The clinical significance of VPs in degenerated IVDs is not fully understood. The purpose of this study is to assess and classify the morphology of IVD ruptures by the presence of intradiscal VPs, and to examine the association between morphological VP-positive IVD ruptures and degenerative lumbar diseases.MethodsIVD rupture was evaluated by the presence of VPs using computed tomography (CT) imaging. VP shape (spot, linear, island) was classified using sagittal imaging, and VP distribution (A-N: anterior AF-NP; N: NP only; N-P: NP-posterior AF; A-N-P: anterior and posterior AF-NP) was classified using axial imaging. The disc height index (DHI) was calculated from lateral radiographs. Disc degeneration and lumbar spinal stenosis were evaluated by MRI grade.ResultsIn the VP shape analysis, the island type was the most common, followed by linear and spot types. In the VP distribution analysis, A-N was the most common group, followed by N, N-P and A-N-P. Intra- and inter-observer reliabilities were statistically sufficient to classify different rupture shapes and distributions. The DHI tended to be lower in discs that contained VPs, especially in the anterior AF area. The shape and distribution of intradiscal VPs were significantly associated with the degree of disc degeneration and lumbar spinal stenosis graded by MRI. Discs with VPs extending from the NP into the anterior and/or posterior AF had a significantly higher proportion of advanced disc degeneration (Pfirrmann’s classification: grades IV and V).ConclusionsThis is the first study to analyze the morphology of IVD rupture evaluated by the presence of intradiscal VPs using CT imaging. This classification can comprehensively present the shape and axial distribution of VPs within IVDs. Intradiscal VPs are associated with the progression of disc degeneration and lumbar spinal stenosis.

BackgroundThe receptor activator of NF-κB ligand (RANKL), a member of the TNF ligand superfamily, is known to regulate bone metabolism. The expression of each component of the RANK/RANKL/osteoprotegerin (OPG) system in the intervertebral disc (IVD) has not been examined in detail. The purposes of this study were to examine the expression of the RANK/RANKL/OPG system and to evaluate the function of RANKL in the matrix metabolism of the rat IVD.MethodsSprague-Dawley, 12-week-old, male rats were used in this study. Anulus fibrosus (AF), nucleus pulposus (NP) and cartilaginous endplate (CEP) cells isolated from dissected thoracolumbar discs were monolayer-cultured. RANK/RANKL/OPG expression in rat IVDs was examined using real-time polymerase chain reaction (PCR) and immunohistochemical analysis (cultured cells and IVD tissues). To examine the effect of interleukin-1β (IL-1β) stimulation on the mRNA levels of RANK, RANKL and OPG, the cells were cultured with or without recombinant human IL-1β (rhIL-1β). To evaluate the effect of RANKL on the mRNA expression of catabolic factors (IL-1β, matrix metalloproteinase-3 (MMP-3) and MMP-13), the cells were cultured with RANKL in the presence or absence of rhIL-1β. The immunohistochemical expression of this system was also evaluated using human IVD tissues with different grades of degeneration.ResultsmRNA expression levels of RANK, RANKL, and OPG were clearly identified in AF, NP and CEP cells. Immunoreactivity to RANK, RANKL and OPG was distributed in the cell membranes and/or cytoplasm of the three types of cells. The mRNA level of RANKL was significantly upregulated by treatment with rhIL-1β of the three types of cells. Treatment with RANKL without rhIL-1β did not induce significant effects on the mRNA expression of catabolic factors by AF, NP and CEP cells. However, the expression was significantly upregulated by stimulation with RANKL in the presence of rhIL-1β. There was a general trend for more RANK/RANKL/OPG-positive cells in human IVD tissues in an advanced stage of degeneration compared to an early stage.ConclusionsOur study showed the possibility that the RANK/RANKL/OPG system may play a part in the process of intervertebral disc degeneration.

Background The expression of the receptor activator of nuclear factor kappa B (RANK) /RANK ligand (RANKL) /osteoprotegerin (OPG) system and its association with the progression of intervertebral disc (IVD) degeneration has recently been reported in a human IVD. However, the effect of the RANK/RANKL/OPG system on the matrix metabolism of human IVD cells, especially on the expression of catabolic factors relevant to IVD degeneration, remains unknown. The purpose of this study was to examine the expression of the RANK/RANKL/OPG system, and then to evaluate the effect of this system on the expression of catabolic factors by human IVD cells. Methods Annulus fibrosus (AF) and nucleus pulposus (NP) cells isolated by sequential enzyme digestion from human IVD tissues obtained during spine surgeries were monolayer cultured. The expression of the RANK/RANKL/OPG system was determined using immunohistochemical methods and real-time polymerase chain reaction (PCR). To evaluate the influence of interleukin-1 beta (IL-1β) stimulation on the mRNA expression of RANK, RANKL, and OPG, recombinant human IL-1β (rhIL-1β) was administered in the culture media of IVD cells. To examine the influence of RANKL signaling on the expression of matrix metalloprotease-3 (MMP-3), MMP-13, and IL-1β, the cells were cultured with exogenous recombinant human RANKL (rhRANKL), recombinant human OPG (rhOPG) or anti-human RANKL mouse monoclonal antibody (ahRANKL-mAB) with or without rhIL-1β. Results Immunoreactivity to RANK/RANKL/OPG and the mRNA expression of the three genes were obviously identified in both AF and NP cells. rhIL-1β stimulation significantly upregulated the mRNA expression level of RANK/RANKL/OPG. The mRNA expression of catabolic factors was significantly upregulated by stimulation of rhRANKL in the presence of rhIL-1β. On the other hand, the administration of either rhOPG or ahRANKL-mAB significantly suppressed the mRNA expression of catabolic factors that had been upregulated by rhIL-1β stimulation. The suppressive effect of ahRANKL-mAB against rhIL-1β stimulation was also confirmed by the protein expression of MMP-3. Conclusions The present study showed that the RANK/RANKL/OPG system may be involved in the progression of IVD degeneration. This study also suggested the potential use of anti-RANKL monoclonal antibody and OPG as therapeutic agents to suppress the progression of IVD degeneration.

BackgroundTitanium (Ti)-6Al-4V alloy, which is widely used in spinal instrumentation with a pedicle screw (PS) system. However, significant clinical problems, including loosening and back-out of PSs, persist. During the last decade, a novel technology that produces bioactive Ti from chemical and heat treatments has been reported that induces the spontaneous formation of a hydroxyapatite (HA) layer on the surface of Ti materials. The purpose of this study was to study the effect of bioactivation of Ti-6Al-4V PSs on the ability of HA formation in vitro and its biocompatibility and bone-bonding ability in vivo.MethodsTi-6V-4Al alloy PSs were prepared and bioactivated by NaOH-CaCl2-heat-water treatments. The HA-forming ability of bioactive PSs in simulated body fluid (SBF) was evaluated by field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX). Six 11-month-old female beagle dogs were used for the in vivo study. Bioactive and control (without bioactivation) PSs were left and right randomly placed from L1 to L6. One and three months after surgery, lumbar spines were removed for biomechanical and histological analyses.ResultsIn vitro: The surface analysis of bioactive PSs by FE-SEM and EDX showed substantial HA deposits over the entire surface. In vivo: The mean extraction torque was significantly higher for bioactive PSs compared to controls PSs (P<0.01); there was no significant difference in pull-out strength between control and bioactive PSs. Histologically, the contact area between bone tissue and screw surface showed no significant trend to be greater in bioactive PSs compared to control PSs (P = 0.06).ConclusionsBioactive PSs prepared by chemical and heat treatments formed layers of HA on the surface of screws in vitro that improved biocompatibility and bonding ability with bone in vivo. Bioactive PSs may reduce screw loosening to overcome the obstacles confronted in spinal instrumentation surgery.

Background Although spinal schwannomas generally grow very slowly, it has been reported that these clinical growths and their associated neurological symptoms accelerate during pregnancy. Because these cases are rare, surgical intervention for this tumor during pregnancy poses a significant challenge. The change of pregnancy-related hormones, such as estrogen and progesterone, is considered to have an effect on the clinical symptoms of spinal tumors. Expressions of the receptors for estrogen and progesterone in orbital and vestibular schwannomas have been reported; however, those expressions in spinal schwannomas have not been examined. Case presentation A 36-year-old woman at 8 weeks' gestation suffered from developing neck pain and neurological symptoms in the right upper extremity. Magnetic resonance imaging (MRI) confirmed the presence of a cervical intradural extramedullary tumor. Under general anesthesia, using intraoperative neurophysiological monitoring of motor-evoked potentials (MEPs), spinal tumor resection following a hemi-laminoplasty was performed in a prone position at 12 weeks gestation. The pathological diagnosis following surgery was spinal schwannoma. Her neurological symptoms were significantly improved after surgery and she delivered a healthy baby in her 40th week of pregnancy. At a 12-month follow-up, no abnormalities were observed during medical examinations of both mother and child. An immunohistochemical study identified the expression of estrogen receptors, but not progesterone receptors, in the spinal schwannoma. Conclusions A cervical spinal schwannoma was successfully removed under general anesthesia at 12 weeks gestation by coordination between orthopaedic, obstetric and anesthesia teams. For the first time, an immunohistochemical analysis showed that the expression of estrogen receptors was identified in spinal schwannoma cells, suggesting the possibility that these hormone receptors in spinal schwannoma might contribute to the worsening of neurological symptoms during pregnancy.

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Study Design. Biochemical and immunohistochemical analyses by the human intervertebral disc (IVD) cells and tissues. Objective. To examine the expression of glial cell line-derived neurotrophic factor (GDNF) and its receptors, GDNF family receptor (GFR) α1 and rearranged during transfection (RET) in the human IVD cells and the tissues with the early and advanced stages of degeneration. Summary of Background Data. The neurotrophin family, including nerve growth factor, has been reported to be expressed in the IVDs and plays a role in hyperalgesia and neuronal sensitization. Despite having properties similar to the nerve growth factor, the expression of GDNF in the IVD remains unknown. Methods. Human IVD cells were cultured in monolayer. Immunohistochemical analyses and western blotting were performed to examine the protein levels of GDNF and its receptors. To examine the effect of proinflammatory cytokines, cells were cultured in the presence of interleukin-1β (IL-1β). The immunohistochemical expression of these proteins was also evaluated using human IVD tissues with different stages of degeneration. Results. Immunofluorescent reactivity against anti-GDNF, GFRα1, and RET antibodies was identified in human IVD cells. In protein extracts from IVD cells, those protein expressions were also identified by Western blot. IL-1β significantly stimulated the mRNA expression of GDNF compared with that of the control group. There was no significant effect of IL-1β on the mRNA expression of GFRα1 and RET. The percentage of GDNF-immunopositive cells in advanced degenerated discs was significantly higher than that in early degenerated discs, whereas those of GFRα1 and RET showed no significant differences. Conclusions. GDNF and its receptors were constitutively expressed in the human IVD cells. GDNF expression was significantly enhanced by proinflammatory stimuli, and in the microenvironment with advanced tissue degeneration. Level of Evidence: N/A.