[O-arm real-time guidance in cervical pedicle screw fixation].

OBJECTIVE: To explore the technical aspects of the accuracy of cervical pedicle screw placement with O-arm guidance. METHODS: The clinical data of 21 patients who underwent cervical pedicle screw fixation by O-arm real-time guidance from December 2015 to January 2020 were analyzed retrospectively. There were 15 males and 6 females, aged from 29 to 76 years old with an average of (45.3±11.5) years. The postoperative CT scan was utilized to evaluate the placement of the pedicle screw and classified according to the Gertzbein and Robbins classification. RESULTS: A total of 132 pedicle screws were implanted in 21 patients, 116 at C3-C6 and 16 at C1 and C2. According to Gertzbein & Robbins classification, the overall breach rates were found to be 11.36% (15/132) with 73.33% (11 screws) Grade B, 26.67% (4 screws) Grade C, and no Grade D or E screw breaches. There were no pedicle screw placement related complications at final follow-up. CONCLUSION: The application of O-arm real-time guidance technology can make cervical pedicle screw placement reliable. High accuracy and better intra-operative control can increase surgeon's confidence in using cervical pedicle instrumentation. Considering the high-risk nature of anatomical area around cervical pedicle and the possibility of catastrophic complications, the spine surgeon should have sufficient surgical skills, experience, ensures stringent verification of the system, and never relies solely on the navigation system.

[Research progress of risk factors of adjacent segment degeneration after anterior cervical discectomy and fusion].

Anterior cervical discectomy and fusion (ACDF) has achieved good clinical results since it was used in clinic, and is considered as the gold standard for the treatment of cervical spondylosis. However, more and more attention has been paid to adjacent segment degeneration(ASDeg) after fusion, and the debate about its pathogenesis is mainly focused on the bio-machanical stress changes of adjacent segments caused by fusion and the result of the natural aging process. The occurrence of ASDeg after fusion seriously affect the med-and long-term outcome of surgery, and some patients even need secondary surgery. In order to reduce or even avoid the occurrence of ASDeg, many new techniques have emerged in clinic, such as artificial disc replacement with preservation of motor segments, emerging cell transplantation technology and so on, but the clinical effect still needs to be confirmed by a large number of studies. Therefore, finding the risk factors of ASDeg after fusion is of great significance for fusion surgery on the clinical work. At present, there is still no unified overview of the research on the risk factors of ASDeg. This article will review the research progress and corresponding countermeasures of the risk factors of ASDeg after ACDF, in order to guide the clinical application.

A numerical simulation method of natural fragment formation and injury to human thorax.

OBJECTIVE: Fragment injury is a type of blast injury that is becoming more and more common in military campaigns and terrorist attacks. Numerical simulation methods investigating the formation of natural fragments and injuries to biological targets are expected to be developed. METHODS: A cylindrical warhead model was established and the formation process of natural fragments was simulated using the approach of tied nodes with failure through the explicit finite element (FE) software of LS-DYNA. The interaction between the detonation product and the warhead shell was simulated using the fluid-structure interaction algorithm. A method to simulate the injury of natural fragments to a biological target was presented by transforming Lagrange elements into smooth particle hydrodynamics (SPH) particles after the natural fragments were successfully formed. A computational model of the human thorax was established to simulate the injury induced by natural fragments by the node-to-surface contact algorithm with erosion. RESULTS: The discontinuous velocities of the warhead shell at different locations resulted in the formation of natural fragments with different sizes. The velocities of natural fragments increased rapidly at the initial stage and slowly after the warhead shell fractured. The initial velocities of natural fragments at the central part of the warhead shell were the largest, whereas those at both ends of the warhead shell were the smallest. The natural fragments resulted in bullet holes that were of the same shape as that of the fragments but slightly larger in size than the fragments in the human thorax after they penetrated through. Stress waves propagated in the ribs and enhanced the injury to soft tissues; additionally, ballistic pressure waves ahead of the natural fragments were also an injury factor to the soft tissues. CONCLUSION: The proposed method is effective in simulating the formation of natural fragments and their injury to biological targets. Moreover, this method will be beneficial for simulating the combined injuries of natural fragments and shock waves to biological targets.

Stromal cell-derived factor-1α promotes recruitment and differentiation of nucleus pulposus-derived stem cells.

BACKGROUND: Intervertebral disc (IVD) degeneration is a condition characterized by a reduction in the water and extracellular matrix content of the nucleus pulposus (NP) and is considered as one of the dominating contributing factors to low back pain. Recent evidence suggests that stromal cell-derived factor 1α (SDF-1α) and its receptor C-X-C chemokine receptor type 4 (CXCR4) direct the migration of stem cells associated with injury repair in different musculoskeletal tissues. AIM: To investigate the effects of SDF-1α on recruitment and chondrogenic differentiation of nucleus pulposus-derived stem cells (NPSCs). METHODS: We performed real-time RT-PCR and enzyme-linked immunosorbent assay to examine the expression of SDF-1α in nucleus pulposus cells after treatment with pro-inflammatory cytokines in vitro. An animal model of IVD degeneration was established using annular fibrosus puncture in rat coccygeal discs. Tissue samples were collected from normal control and degeneration groups. Differences in the expression of SDF-1α between the normal and degenerative IVDs were analyzed by immunohistochemistry. The migration capacity of NPSCs induced by SDF-1α was evaluated using wound healing and transwell migration assays. To determine the effect of SDF-1α on chondrogenic differentiation of NPSCs, we conducted cell micromass culture and examined the expression levels of Sox-9, aggrecan, and collagen II. Moreover, the roles of SDF-1/CXCR4 axis in the migration and chondrogenesis differentiation of NPSCs were analyzed by immunofluorescence, immunoblotting, and real-time RT-PCR. RESULTS: SDF-1α was significantly upregulated in the native IVD cells cultured in vitro with pro-inflammatory cytokines, such as interleukin-1ß and tumor necrosis factor-α, mimicking the degenerative settings. Immunohistochemical staining showed that the level of SDF-1α was also significantly higher in the degenerative group than in the normal group. SDF-1α enhanced the migration capacity of NPSCs in a dose-dependent manner. In addition, SDF-1α induced chondrogenic differentiation of NPSCs, as evidenced by the increased expression of chondrogenic markers using histological and immunoblotting analyses. Real-time RT-PCR, immunoblotting, and immunofluorescence showed that SDF-1α not only increased CXCR4 expression but also stimulated translocation of CXCR4 from the cytoplasm to membrane, accompanied by cytoskeletal rearrangement. Furthermore, blocking CXCR4 with AMD3100 effectively suppressed the SDF-1α-induced migration and differentiation capacities of NPSCs. CONCLUSION: These findings demonstrate that SDF-1α has the potential to enhance recruitment and chondrogenic differentiation of NPSCs via SDF-1/CXCR4 chemotaxis signals that contribute to IVD regeneration.

Characteristics and potentials of stem cells derived from human degenerated nucleus pulposus: potential for regeneration of the intervertebral disc.

BACKGROUND: Eliminating the symptoms during treatment of intervertebral disc degeneration (IVDD) is only a temporary solution that does not cure the underlying cause. A biological method to treat this disorder may be possible by the newly discovered nucleus pulposus derived stem cells (NPDCs). However, the uncertain characteristics and potential of NPDCs calls for a comprehensive study. METHODS: In the present study, nucleus pulposus samples were obtained from 5 patients with IVDD undergoing discectomy procedure and NPDCs were harvested using fluorescence activated cell sorting (FACS) by the co-expression of GD2+ and Tie2+. After in vitro expansion, the properties of NPDCs were compared with those of bone marrow mesenchyme stem cells (BMSCs) from the same subjects. RESULTS: NPDCs performed similar properties in cell colony-forming ability, cell proliferation rate, cell cycle and stem cell gene expression similar to those of BMSCs. In addition, NPDCs could be differentiated into osteoblasts, adipocytes, and chondrocytes, and are found to be superior in chondrogenesis but inferior in adipocyte differentiation. CONCLUSIONS: NPDCs derived from the degenerated intervertebral disc still keep the regeneration ability similar to BMSCs. Besides, the superior capacity in chondrogenesis may provide a promising cell candidate for cell-based regenerative medicine and tissue engineering in IVDD.

* Coculture with Partial Digestion Notochordal Cell-Rich Nucleus Pulposus Tissue Activates Degenerative Human Nucleus Pulposus Cells.

Recent studies suggested that notochordal cells (NCs) and NC-conditioned medium (NCCM) can stimulate cell viability and matrix production of nucleus pulposus cells (NPCs). However, the potential of notochordal cell-rich nucleus pulposus (NRNP) incorporating the native environment of the intervertebral disc (IVD) has not been evaluated. The objective of this study was to develop an optimal NRNP model and test whether it can allow a significant level of NPC activation in vitro. Rabbit NRNP explants were divided into three groups according to different digestion time: digestion NRNP of 8 h, partial digestion NRNP of 2 h, and natural NRNP. Cell viability and NC phenotype were compared between these groups after 14 days of incubation. The products of the selected partial digestion NRNP group were then cocultured with human degenerated NPCs for 14 days. NPC viability, cell proliferation and senescence, the production of glycosaminoglycan (GAG) found in extracellular matrix, and NP matrix production by NPCs were assessed. The results showed that coculturing with partial digestion NRNP significantly improved the cell proliferation, cell senescence, and disc matrix gene expression of NPCs compared with those in the monoculture group. In addition, GAG/DNA ratio in the coculture group increased significantly, while the level of collagen II protein remained unchanged. In this study, we demonstrated that partial digestion NRNP may show a promising potential for NPC regeneration in IVD tissue engineering.

Imaging Evaluation and Relative Significance in Cases of Cervical Disk Allografting: Radiographic Character After Total Disk Transplantation.

STUDY DESIGN: The clinical and radiologic data of total disk allografting (TDA) cases were collected and analyzed to explore the correlation between neurological function improvements and imaging changes. OBJECTIVE: The aim of the study was to assess the medium-term and long-term outcome and radiographic character after TDA, and, furthermore, to explore the significance of the changes of imaging signs after the transplantation. SUMMARY OF BACKGROUND DATA: Spinal fusion may result in the adjacent segment degeneration. The anxiousness urged the necessity for the development of TDA to reduce the risk of adjacent segment degeneration. Both animal studies and recent clinical trials have shown promising results to support the use of intervertebral disk allograft as a natural mobile disk replacement. METHODS: The conditions of 13 cases that underwent TDA after cervical discectomy were recorded in detail. Axial symptoms and neurological function in various periods were assessed, and, meanwhile, radiologic examination was performed for the comprehensive evaluation of the relevant indicators before and after surgery. RESULTS: (1) There was significant improvement in the neurological function after TDA. Postoperatively, the Visual Analog Score of axial symptoms did not increase significantly. (2) Both the entire and local segment maintained a satisfactory curve after allografting. There was no obvious correlation between the neurological function recovery and the cervical curve. Besides, the motion of the cervical spine did not change postoperatively. (3) Postoperatively, the spinal cord area at the index level increased significantly, whereas the signal value of the transplanted disk decreased sharply. CONCLUSIONS: (1) Disk allografting is one of the effective and safe methods in treating the diseases of cervical disk herniation. (2) Although some degeneration occurs in the transplanted disk, the allograft can still be alive and can successfully maintain and improve the biological characters of the cervical spine in both radiologic and practical aspects.

BMP7-Based Functionalized Self-Assembling Peptides Protect Nucleus Pulposus-Derived Stem Cells From Apoptosis In Vitro.

Tissue engineering has shown great success in the treatment of intervertebral disk degeneration (IVDD) in the past decade. However, the adverse and harsh microenvironment associated in the intervertebral disks remains a great obstacle for the survival of transplanted cells. Although increasing numbers of new materials have been created or modified to overcome this hurdle, a new effective strategy of biological therapy is still required. In this study, bone morphogenic protein 7 (BMP7)-based functionalized self-assembling peptides were developed by conjugating a bioactive motif from BMP-7 (RKPS) onto the C-terminal of the peptide RADARADARADARADA (RADA16-I) at a ratio of 1:1 to form a new RADARKPS peptide. Human nucleus pulposus-derived stem cells (NPDCs) were cultured in the presence of RADA-RKPS or RADA16-I in an apoptosis-promoting environment that was induced by tumor necrosis factor-alpha, and cells were cultured with RADA16-I in normal medium that served as the control group. After 48 h of apoptosis induction, the viability, proliferation, apoptosis rate, and expression of apoptosis-related genes of NPDCs in the different groups were evaluated, and the differentiation of NPDCs toward nucleus pulposus-like cells was tested. The results showed that the RADA-RKPS peptide could significantly protect the survival and proliferation of NPDCs. In addition, the application of RADA-RKPS decreased the rate of cell apoptosis, as detected by TUNEL-positive staining. Furthermore, our in vitro study confirmed the apoptosis-protecting effects of RADA-RKPS peptides, which significantly reduced the BAX/BCL-2 ratio of NPDCs and upregulated the gene expression of collagen II a1, aggrecan, and Sox-9 after 48 h of apoptosis induction. Collectively, these lines of evidence suggest that RADA-RKPS peptides confer a protective effect to NPDCs in an apoptosis environment, suggesting their potential application in the development of new biological treatment strategies for IVDD.

[Factors of prognosis in cervical spondylotic myelopathy: a review].

Cervical spondylotic myelopathy (CSM) is a common cause of spinal cord dysfunction clinical disease. Surgery is the main therapeutic tool for CSM. However, there are obvious differences in clinical functional recovery after operation. For the past few years, the influence factors of prognosis in cervical spondylosis myelopathic has been widely concerned. Age, nerve function, course of desease, imaging findings,surgical method and related factors became the investigative point for prognosis of cervical spondylotic myelopathy. Present viewpoint showed that the older patient, preoperative worse nerve function, longer the course of disease would result in worse outcomes. Imaging examination maybe can indicate the prognosis, but the correlation is unclear. Selection of surgical method and approach should be based on the principles of sufficient decompression, stabilize the alignment of the cervical spine, keeping backward extension of cervical spine, maintain effective decompression, preventing complications. Therefore, the treatment of cervical spondylotic myelopathy should be on the basis of pathogenic condition and imaging examination at early stage and a suitable usrgical procedure should be performed to obtain a better prognosis.

Computed tomography-guided nucleus pulposus biopsy for canine intervertebral disc degeneration preparation: a radiology and histology study.

BACKGROUND CONTEXT: Different animal models are being used in disc degenerative disease (DDD) research; most of these models are induced invasively rather than noninvasively. Computed tomography (CT)-guided percutaneous biopsy, widely used in clinical malignant pathology diagnosis, is a safe, useful, and highly accurate procedure. However, this process was not carried out in animal model preparation of intervertebral disc degeneration. PURPOSE: To apply a minimally invasive method in DDD animal model preparation with a biopsy gun guided by CT scan and evaluate the accuracy and efficiency of this process with radiology and histology analyses. The relationship between the weight of removed nucleus pulposus (NP) and the degenerative process was also explored preliminarily. METHODS: The canine intervertebral discs L1-L2, L3-L4, and L5-L6 were divided into three groups randomly: Group A: 18G biopsy gun; Group B: 20G biopsy gun; and Group C: 24G biopsy gun. After the lumbar spine was scanned with CT and the depth and angle of the centesis operation sites ascertained, biopsy gun was stabbed percutaneously through the annulus into the NP. A certain volume of NP tissue was removed by the biopsy gun. Radiology examination, including digital radiography (DR) and magnetic resonance imaging (MRI), was carried out preoperatively and at first and third months postoperatively. Each sample was harvested at the 3rd month postoperation for histology evaluation. RESULTS: Computed tomography-guided percutaneous biopsy with 18G, 20G, and 24G biopsy guns was carried out for six discs, respectively. In the procedure, the weight of the NP tissue was removed: 3.0±0.53mg in Group A, 2.01±0.34 mg in Group B, and 0.99±0.12 mg in Group C. Significant differences of the weight of the removed NP tissue were calculated between groups (p<.05). During the observation period, although the disc height of Group A and B was reduced, no significant differences in the disc height comparison were found between groups at each time point and within groups at different time points in DR analysis. However, the signal intensity of MRI was reduced significantly (p<.05) in Group A when compared with Group C at third month, whereas the signal intensity was decrease mildly (p>.05) in Group B when compared with Group C at third month. The decreased content of NP, the number of NP cells, and the loose annulus fibrosus at the inner area was observed in both hematoxylin-eosin and Safranin-O staining in Group A at the 3rd month postoperation. CONCLUSIONS: Computed tomography-guided percutaneous biopsy could be applied in intervertebral disc degeneration preparation of canine model, and the 20G biopsy gun would be the optimal choice in this procedure. The intervertebral disc degenerative process could be forecasted approximately on an account of the negative association between the degeneration process and the weight of the removed NP tissue.

Growing trend of China's contribution to the field of spine: a 10-year survey of the literature.

PURPOSE: China, as a rapidly developing country with the largest population including over 50,000 orthopaedic surgeons, has an increasing importance in the field of spine. However, the quantity and quality of research production in the field of spine in the major regions of China-Mainland China, Taiwan, and Hong Kong is unclear. This study aimed to investigate the contribution of China to the field of spine. METHODS: Articles published in the 5 major spine journals originating from Mainland China, Taiwan and Hong Kong in 2004-2013 were retrieved from the database of Web of Science. The number of articles, impact factors, citations, article type, city, institution, funding source and conflict of interest were analyzed. RESULTS: There were 1006 publications in the 5 spine journals between 2004 and 2013 from China, including 706 from Mainland China, 210 from Taiwan, and 90 from Hong Kong. The time trend of the number of articles from these three regions showed a significant increase of 8.74-fold (from 23 to 201) between 2004 and 2013 (p = 0.000). From 2006, the number of publications from Mainland China exceeded Taiwan and Hong Kong. Mainland China had the highest total impact factors (1686.54) and total citations (4214), followed by Taiwan (498.93; 2009) and Hong Kong (222.89; 1311). Hong Kong had the highest mean impact factor (2.48) and mean citations (14.46), followed by Mainland China (2.40; 10.26) and Taiwan (2.38; 10.14). The journal Spine published the largest number of articles (470), followed by European Spine Journal (268). CONCLUSIONS: Chinese contributions to the field of spine have a significant increase during the past 10 years, particularly from Mainland China. Hong Kong had the highest quality research output in terms of mean impact factor and mean citation per article.

[Case-control study on patellar fixed pin and Kirschner's nail with tension band for the treatment of patellar fracture].

OBJECTIVE: To compare the clinical efficiency of patellar fixed pin and Kirschner's nail with tension band in treating patellar fracture. METHODS: From November 2010 to January 2012, the clinical data of 42 patients with patella fracture were treated with patella fixed needle and Kirschner's nail with tension band. The patellar fixed needle group included 21 cases (14 males and 7 females,aged 26 to 65 with an average of 43.6 years old); The Kirschner's nail with tension band group included 21 cases (12 males and 9 females,aged 32 to 58 with an average of 41.5 years old). The operation time, intra-operative blood loss and healing time were compared between two groups. Böstman score was applied to compare the therapeutic effects. RESULTS: All patients were followed up with an average of 11.5 months ranged from 6 to 14 months. The fractures healed well without complications such as nonunion and infection. According to Böstman score, there was no significant difference between two groups in clinical efficiency (Z = -0.83, P = 0.407). There was significant difference in operation time (t = 6.67, P = 0.00), while no difference in intra-operative blood loss, bone healing time (t = 1.90, P = 0.064; t = 0.612, P = 0.544). CONCLUSION: Both methods can obtain good results. However, patellar fixed pin combined with tension band is one of the ideal methods for the treatment of patellar fracture, it has an advantage of simple with shorter operation time, rigid fixation, less complications and well recovery.

Changes in T lymphocyte subsets and intracellular cytokines after transfer of chemically extracted acellular nerve allografts.

The aim of the present study was to observe the immune mechanism underlying the rejection of chemically extracted acellular nerve allografts for use in clinical applications. A total of 128 BALB/c mice were randomly divided into a negative contrast group (NC, 32 mice), a fresh autograft group (AG, 32 mice), a fresh allogeneic nerve group (FN, 32 mice) and a chemically extracted acellular allogeneic nerve group (CEN, 32 mice). Various types of nerve grafts were implanted into the thigh muscle of BALB/C mice in the corresponding groups. At 3, 7, 14 and 28 days post-operation, the mice (8 cases from each group) were sacrificed and their spleens were extracted. The spleens were ground into paste. The erythrocytes and other cells were lysed using distilled water and the T lymphocytes were collected. Monoclonal antibodies (CD3, CD4, CD8, CD25, IL-2, IFN-γ and TNF-α) were then added to the solution. The Facial Action Coding System was used to determine the positive rates of the cells combined with the monoclonal antibodies above. No significant statistical differences were observed between the CEN, NC and AG groups. However, some data of the FN group were significantly higher than those of the other groups at the corresponding time. No obvious immune rejections were observed among the chemically extracted acellular nerve allografts compared with fresh nerve autograft.

[Reasearch on mechanism of neurotrophins in discogenic low back pain].

Discogenic low back pain is the common type of chronic low back pain. However,its mechanism has not been completely clarified. Considerable evidence shows that neurotrophins play an important role in discogenic low back pain. The paper summarizes the mechanism of neurotrophins on discogenic low back pain according to the pain transfer pathway of neurotrophins in intervertebral disc, dorsal horn ganglia and spinal trigeminal nucleus. Changing the pain transmission by regulating neurotrophins and its receptor will provide a new way for the treatment of discogenic low back pain.

[The clinical observation about Coflex of dynamic interspinous implant on the treatment of lumbar spinal stenonis].

OBJECTIVE: To identify the initial effect of dynamic interspinous implant of Coflex on the treatment of lumbar spinal stenosis. METHODS: A retrospective study of 18 patients who underwent posterior lumbar decompression and fixation with interspinous implant of Coflex between March 2008 and October 2009 was taken to compare the Cobb angel of nature and dynamic position on the segment of Coflex fixation at the time of before and after operation and following time,including 10 males and 8 females with average age of 62.2 years old (54 to 71 years). The symptoms of patients included chronic lower back pain and intermittent claudication and lower extremity numbness. All cases including 17 cases of L4,5 and 1 case of L3,4 were central canal stenosis without obviously segmental instability. Clinical outcomes were evaluated with VAS and ODI. RESULTS: All patients were followed up from 10 to 18 months with an average of 14.4 months. There did not about internal fixation failure. It was found that postoperative Cobb angel of fixation segment [(12.1 +/- 2.6) degrees] was significantly decreased than preoperative [(14.8 +/- 3.2) degrees] (t = 2.61, P = 0.03). But the Cobb angel [(14.9 +/- 4.1) degrees] increased at final follow-up, even reached the level of before operation (t = 1.39, P = 0.65). The Cobb angle of upper adjacent segment did not obviously change in preoperation, postoperation and final follow-up [(12.1 +/- 2.3) degrees, (12.3 +/- 3.2) degrees, (11.9 +/- 3.0) degrees, respectively]. Dynamic measure showed that Coflex can adequately limit the ROM of extension (t = 4.01, P = 0.001), but the ROM of flexion increased (t = 2.57, P = 0.02). The VAS score in follow-up (2.2 +/- 0.7) was significantly decreased than before operation (4.9 +/- 1.1, t = 2.95, P = 0.02). The ODI score in follow-up [(29.1 +/- 9.0)%] was significantly decreased than before operation [(56.5 +/- 14.2)%, (t = 3.02, P = 0.02)]. CONCLUSION: The Coflex implanting combined with decompression can get good result clinically, but imaging showed that Coflex can not maintain the relatively kyphosis gained after operation except for extension limitation.

Effects of adeno-associated virus-2-mediated human BMP-7 gene transfection on the phenotype of nucleus pulposus cells.

Bone morphogenetic protein-7 (BMP-7) was found to stimulate the synthesis of proteoglycans (PGs) and collagen type II. To increase the biological function of the nucleus pulposus (NP) cells, the Ad-hBMP-7 vector was also successfully constructed and transfected NP cells. However, the disadvantages of adenovirus limit the usefulness of the Ad-hBMP7 vector for clinical application. The rAAV2 vector has empirical advantages, especially for clinical use, to transfer exogenous genes into cells. The purpose of this study was to first determine whether a rAAV2-hBMP-7 vector could be used to transfect canine NP cells and effect on the biological functions of canine NP cells. The canine NP cells transfected by the rAAV-BMP7 were assessed semi-quantitatively for BMP-7 expression with real-time PCR and westernbloting. Aggrecan and collagens type I and II secreted by the NP cells were qualitatively assessed at 4, 7, and 14 days post-transfection in the transfection and control groups. We found that rAAV2 can successfully transfer the hBMP-7 gene into canine NP cells. NP cells transfected by the rAAV-hBMP-7 vector express hBMP-7 for at least 14 days. At 7 and 14 days, the expressed hBMP-7 promotes a remarkable and significant accumulation of both proteoglycans (42% and 77% higher than non-transfected cells) (p<0.05) and collagen type II (63% and 94% higher than non-transfected cells) (p<0.05). Thus, we could speculate that the rAAV-based gene delivery technique promotes the expression of proteoglycans and collagen type II of nucleus pulposus cells. Moreover, this technique may be applicable for the future treatment of degenerative disc disease.