[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.

MCP­1/CCR2 axis inhibits the chondrogenic differentiation of human nucleus pulposus mesenchymal stem cells.

Intervertebral disc degeneration (IDD) creates a hostile environment with high osmotic pressure, high mechanical stress, hypoxia and a low pH, where cytokines such as TNF­α and IL­1ß are highly expressed. The degenerating intervertebral disc has high local expression of monocyte chemoattractant protein­1 (MCP­1), which is associated with the degree of degeneration. However, there are a few reports on the influence of MCP­1 on nucleus pulposus­derived stem cells (NPSCs). In the present study, a significant upregulation of MCP­1 was observed in NPSCs cultured in vitro with pro­inflammatory cytokines. MCP­1 significantly inhibited the migration and proliferation of NPSCs in a dose­dependent manner as detected via Cell Counting Kit­8, wound healing and Transwell assays. Western blotting and histological analysis demonstrated that MCP­1 significantly reduced chondrogenic NPSC differentiation. Reverse transcription­quantitative PCR and western blotting revealed that C­C chemokine receptor type 2 (CCR2) mRNA and protein expression levels were significantly enhanced by MCP­1. Furthermore, MCP­1 significantly inhibited the migration, differentiation and proliferation of NPSCs, which was effectively reversed by blocking CCR2 with the inhibitor RS504393. Overall, these results demonstrated that MCP­1 may contribute to the inhibition of chondrogenic NPSC differentiation via MCP­1/CCR2 chemotaxis signals, providing a potential therapeutic target for IDD.

Intradiscal Injection of Autologous Discogenic Cells in Patients with Discectomy: A Prospective Clinical Study of Its Safety and Feasibility.

The treatment of intervertebral disc degeneration (IVDD) is still a huge challenge for clinical updated surgical techniques and basic strategies of intervertebral disc regeneration. Few studies have ever tried to combine surgery and cell therapy to bridge the gap between clinical and basic research. A prospective clinical study with a 72-month follow-up was conducted to assess the safety and feasibility of autologous discogenic cells transplantation combined with discectomy in the treatment of lumbar disc herniation (LDH) and to evaluate the regenerative ability of discogenic cells in IVDD. Forty patients with LDH who were scheduled to have discectomy enrolled in our study and were divided into the observed group (transplantation of autologous discogenic cells after discectomy) and control group (only-discectomy). Serial MRI and X-ray were used to evaluate the degenerative extent of index discs, and clinical scores were used to determine the symptomatic improvement. No adverse events were observed in the observed group, and seven patients in the control group underwent revisions. Both groups had significant improvement of all functional scores post-operatively, with the observed group improving more considerably at 36-month and 72-month follow-up. The height and water content of discs in both groups decreased significantly since 36 months post-op with the control group decreased more obviously. Discectomy combined with autologous discogenic cells transplantation is safe and feasible in the treatment of LDH. Radiological analysis demonstrated that discogenic cells transplantation could slow down the further degeneration of index discs and decrease the complications of discectomy.

Cluster phenomenon of vertebral refractures after posterior pedicle screw fixation in a patient with glucocorticosteroid-induced Kümmell's disease: a treatment dilemma.

INTRODUCTION: Surgical treatments are usually preferred in patients with Kümmell's disease since it represents a failure of conservative treatment for osteoporotic vertebral compression fracture without evidence of spontaneous healing. However, the risk of postoperative refractures is much higher in patients with glucocorticosteroid-induced osteoporosis (GIOP) than in those with primary osteoporosis, possessing a therapeutic challenge and dilemma to orthopaedic surgeons. CASE REPORT: We described a rare cluster phenomenon of vertebral refractures in a patient with GIOP subsequent to segmental internal fixation for the initial management of glucocorticosteroid-induced Kümmell's disease, and a review of the literature. CONCLUSION: Our patient illustrates that clinicians should be aware of the significant management dilemma and possible disastrous outcome after surgical interventions for glucocorticosteroid-induced Kümmell's disease and, thus, pay much more attention to comprehensive perioperative antiosteoporotic medications for patients with GIOP in current medical treatment.

The Role of Unfolded Protein Response in Human Intervertebral Disc Degeneration: Perk and IRE1-α as Two Potential Therapeutic Targets.

Inflammation plays a key role in intervertebral disc degeneration (IDD). The association between inflammation and endoplasmic reticulum (ER) stress has been observed in many diseases. However, whether ER stress plays an important role in IDD remains unclear. Therefore, this study is aimed at investigating the expression of ER stress in IDD and at exploring the underlying mechanisms of IDD, ER stress, and inflammation. The expression of ER stress was activated in nucleus pulposus cells from patients who had IDD (D-NPCs) compared with patients without IDD (N-NPCs); and both the proliferation and synthesis capacity were decreased by inducer tunicamycin (Tm) and proinflammatory cytokines. Pretreatment of NPCs with 4-phenyl butyric acid (4-PBA) prevented the inflammatory cytokine-induced upregulation of unfolded protein response- (UPR-) related proteins and recovered cell synthetic ability. Furthermore, proinflammatory cytokine treatment significantly upregulated the expression of inositol-requiring protein 1 (IRE1-α) and protein kinase RNA-like ER kinase (PERK), but not activating transcription factor 6 (ATF6). Finally, knockdown of IRE1-α and PERK also restored the biological activity of NPCs. Our findings identified that IRE1-α and PERK might be the potential targets for IDD treatment, which may help illustrate the underlying mechanism of ER stress in IDD.

Lumbar plain radiograph is not reliable to identify lumbosacral transitional vertebra types according to Castellvi classification principle.

BACKGROUND: The anteroposterior view of the lumbar plain radiograph (AP-LPR) was chosen as the original and first radiographic tool to determine and classify lumbosacral transitional vertebra with morphological abnormality (MA-LSTV) according to the Castellvi classification. However, recent studies found that AP-LPR might not be sufficient to detect or classify MA-LSTV correctly. The present study aims to verify the reliability of AP-LPR on detecting and classifying MA-LSTV types, taking coronal reconstructed CT images (CT-CRIs) as the gold criteria. METHODS: Patients with suspected MA-LSTVs determined by AP-LPR were initially enrolled. Among them, those who received CT-CRIs were formally enrolled to verify the sensitivity of AP-LPR on detecting and classifying MA-LSTV types according to the Castellvi classification principle. RESULTS: A total of 298 cases were initially enrolled as suspected MA-LSTV, among which 91 cases who received CT-CRIs were enrolled into the final study group. All suspected MA-LSTVs were verified to be real MA-LSTVs by CT-CRIs. However, 35.2% of the suspected MA-LSTV types judged by AP-LPR were not consistent with the final types judged by CT-CRIs. Two suspected type IIIa and 20 suspected type IIIb MA-LSTVs were verified to be true, while 9 of 39 suspected type IIa, 9 and 3 of 17 suspected type IIb, and 11 of 13 suspected type IV MA-LSTVs were verified to truly be type IIIa, IIIb, IV and IIIb MA-LSTVs by CT-CRIs, respectively. Incomplete joint-like structure (JLS) or bony union structure (BUS) and remnants of sclerotic band (RSB) between the transverse process (TP) and sacrum were considered to be the main reasons for misclassification. CONCLUSION: Although AP-LPR could correctly detect MA-LSTV, it could not give accurate type classification. CT-CRIs could provide detailed information between the TP and sacrum area and could be taken as the gold standard to detect and classify MA-LSTV.

The inflammatory cytokine TNF-α regulates the biological behavior of rat nucleus pulposus mesenchymal stem cells through the NF-κB signaling pathway in vitro.

Nucleus pulposus (NP) mesenchymal stem cells (NPMSCs) are a potential cell source for intervertebral disc (IVD) regeneration; however, little is known about their response to tumor necrosis factor-α (TNF-α), a critical inflammation factor contributing to accelerating IVD degeneration. Accordingly, the aim of this study was to investigate the regulatory effects of TNF-α at high and low concentrations on the biological behaviors of healthy rat NPMSCs, including proliferation, migration, and NP differentiation. In this study, NPMSCs were treated with different concentration of TNF-α (0-200 ng/mL). Then we used annexin V/propidium iodide flow cytometry analysis to detect the apoptosis rate of NPMSCs. Cell Counting Kit-8, Edu assay, and cell cycle test were used to examine the proliferation of NPMSCs. Migration ability of NPMSCs was detected by wound healing assay and transwell migration assay. Pellets method was used to induce NP differentiation of NPMSCs, and immunohistochemical staining, real-time polymerase chain reaction, and Western blot analysis were used to examine the NPC phenotypic genes and proteins. The cells were further treated with the nuclear factor-κB (NF-κB) pathway inhibitor Bay 11-7082 to determine the role of the NF-κB pathway in the mechanism underlying the differentiation process. Results showed that treatment with a high concentration of TNF-α (50-200 ng/mL) could induce apoptosis of NPMSCs, whereas a relatively low TNF-α concentration (0.1-10 ng/mL) promoted the proliferation and migration of NPMSCs, but inhibited their differentiation toward NP cells. Moreover, we identified that the NF-κB signaling pathway is activated during the TNF-α-inhibited differentiation of NPMSCs, and the NF-κB signal inhibitor Bay 11-7082 could partially eliminate the adverse effect of TNF-α on the differentiation of NPMSCs. Therefore, our findings provide important insight into the dynamic biological behavior reactivity of NPMSCs to TNF-α during IVD degeneration process, thus may help us understanding the underlying mechanism of IVD degeneration.

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.

Radiographic analysis of the correlation between ossification of the nuchal ligament and sagittal alignment and segmental stability of the cervical spine in patients with cervical spondylotic myelopathy.

BACKGROUND: Ossification of the nuchal ligament (ONL) caused by chronic injury to the nuchal ligament (NL) is very common in instability-related cervical disorders. PURPOSE: To determine possible correlations between ONL, sagittal alignment, and segmental stability of the cervical spine. MATERIAL AND METHODS: Seventy-three patients with cervical spondylotic myelopathy (CSM) and ONL (ONL group) and 118 patients with CSM only (control group) were recruited. Radiographic data included the characteristics of ONL, sagittal alignment and segmental stability, and ossification of the posterior longitudinal ligament (OPLL). We performed comparisons in terms of radiographic parameters between the ONL and control groups. The correlations between ONL size, cervical sagittal alignment, and segmental stability were analyzed. Multivariate logistic regression was used to identify the independent risk factors of the development of ONL. RESULTS: C2-C7 sagittal vertical axis (SVA), T1 slope (T1S), T1S minus cervical lordosis (T1S-CL) on the lateral plain, angular displacement (AD), and horizontal displacement (HD) on the dynamic radiograph increased significantly in the ONL group compared with the control group. The size of ONL significantly correlated with C2-C7 SVA, T1S, AD, and HD. The incidence of ONL was higher in patients with OPLL and segmental instability. Cervical instability, sagittal malalignment, and OPLL were independent predictors of the development of ONL through multivariate analysis. CONCLUSION: Patients with ONL are more likely to have abnormal sagittal alignment and instability of the cervical spine. Thus, increased awareness and appreciation of this often-overlooked radiographic finding is warranted during diagnosis and treatment of instability-related cervical pathologies and injuries.

Successful Conservative Management of Delayed Cervical Spondylodiscitis with Epidural Abscess Caused by Esophageal Diverticulitis: A Case Report and Review of Literature.

BACKGROUND: Cervical spondylodiscitis with spinal epidural abscess (SEA) is not a rare medical condition and usually requires urgent decompression of neural structures and stabilization of the spine followed by antibiotic therapy for the prevention of severe neurologic deficits. CASE DESCRIPTION: In this report, we present a 43-year-old male patient with the chief complaint of neck pain and intermittent fever accompanying by slight dysphagia. After 2 weeks, he felt mild and transient numbness on the left upper limb. He had a history of esophageal intervention under endoscopy. Magnetic resonance imaging disclosed diffuse hyperintensity in the left paraesophageal and prevertebral tissues and a space-occupying lesion within the spinal canal. The esophagography revealed a saclike barium collection parallel to the upper esophagus herniating out from the posterior wall without evident leakage. Neither surgical decompression nor drainage was chosen by this patient; conservative treatment with antibiotic administration was managed to achieve a good neurologic recovery and remarkable resolution of the epidural abscess. During antibiotic therapy and dietary restriction, the symptoms of diverticulitis was also managed expectantly. CONCLUSIONS: Physicians need to be aware of this rare case of SEA secondary to esophageal diverticulitis. An early diagnosis and prompt administration of antibiotics is a key factor to avoid neurologic deterioration for the treatment of SEA caused by diverticulitis. Endoscopic or surgical repair of diverticulum may be warranted to avoid the recurrence of such infection.

"Acquired" Type Castellvi-IIIa Lumbarization Transformed From Castellvi-IIa Following Discectomy and Fusion at Lumbosacral Level: A Case Report.

STUDY DESIGN: A retrospective case report. OBJECTIVE: To report a case that transformed from type Castellvi-IIa sacralization to type Castellvi-IIIa after decompression and fusion surgery at transitional disc (TD). SUMMARY OF BACKGROUND DATA: Traditionally, lumbosacral transitional vertebra has been regarded as a congenital anomaly. No literature has ever reported that transformation from one type lumbosacral transitional vertebra to another would happen after birth. METHODS: A 60-year-old man presented to our department with the complaint of low back pain and left sciatic pain, and was diagnosed of lumbar disc herniation at L4-5 and L5-S1 levels. Lumbar digital radiography revealed an anomalous articulation formed between sacrum and enlarged right L5 transverse process, exhibiting a typical Castellvi-IIa sacralization. Dynamic lateral radiographs showed mobilization existed at L5-S1 disc which was TD. The patient received posterior lumbar interbody fusion (PLIF) surgery at L4-5 and L5-S1 levels. Postoperative computed tomography examinations were taken to identify the progress of solid fusion at the operated segments. RESULTS: After surgery, the patient's symptoms alleviated obviously. As solid fusion developed at intended interbody regions with time, we found that bony bridge passed through the patient's anomalous articulation region gradually, and finally, complete osseous fusion of the right L5 transverse process to the sacrum developed 1 year after surgery. CONCLUSION: Following PLIF surgery at TD segment on a Castellvi-IIa Sacralization case, "acquired" transformation to Castellvi-IIIa might develop. LEVEL OF EVIDENCE: 5.

Functional self-assembled peptide scaffold inhibits tumor necrosis factor-alpha-induced inflammation and apoptosis in nucleus pulposus cells by suppressing nuclear factor-κB signaling.

Although nucleus pulposus (NP) tissue engineering has achieved tremendous success, researches still face the huge obstacles in maintaining cell survival and function. A novel functional self-assembled peptide RADA-KPSS was constructed by conjugating BMP-7 short active fragment (KPSS) to the C-terminus of RADA16-I that displays anti-inflammatory and anti-apoptosis effects. However, whether this functional self-assembled RADA-KPSS peptide can alleviate inflammation and NPC apoptosis induced by tumor necrosis factor-alpha (TNF-α) has not been studied. Therefore, we cultured NPCs treated with TNF-α for 48 h with the RADA-KPSS peptide, and compared the results to those with RADA16-I peptide. The cell apoptosis rate, inflammatory mediator secretion, expression of matrix-degrading enzymes, and extracellular matrix (ECM) protein levels were evaluated. The expression of nuclear factor-κB-p65 (NF-κB-p65) protein was also tested. TNF-α-treated NPCs cultured with the RADA16-I peptide showed up-regulated gene expression for matrix-degrading enzymes, such as matrix metalloproteinases-3 (MMP-3), MMP-9, and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-4), and down-regulated gene expression for ECM proteins such as aggrecan, collagen II, and Sox-9. The RADA-KPSS peptide could attenuate the expression of MMP-3, MMP-9, and ADAMTS-4, promote accumulation of ECM proteins, and increase secretion of glycosaminoglycan as compared with the RADA16-I peptide. Moreover, the TNF-α-damaged NPCs was further demonstrated to inhibit NF-κB-p65, IL-1, IL-6, and prostaglandin E-2 proteins and decrease cell apoptosis in RADA-KPSS peptide. In conclusion, the functional self-assembled RADA-KPSS peptides have anti-inflammatory and anti-apoptotic effects by promoting anabolic processes and inhibiting catabolic processes in intervertebral disk degeneration. These peptides may be feasible for clinical applications in NP tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1082-1091, 2018.

BMP7-Based Functionalized Self-Assembling Peptides for Nucleus Pulposus Tissue Engineering.

Nucleus pulposus (NP) tissue engineering has been demonstrated to be a feasible therapeutic strategy for intervertebral disc regeneration. In this study, we constructed a novel injectable biomaterial by conjugating three different short peptides of BMP7 to the C-terminus of the self-assembling peptide RADA16-I, and we then mixed each of these conjugates with RADA16-I at equal volumes to obtain the novel functionalized peptides RAD-SNV, RAD-KPS, and RAD-KAI. The bioactivities of these functionalized peptides for human degenerated NP cells (hdNPCs) were evaluated in vitro, and the most ideal scaffold was chosen for assessment of its in vivo degradation and the tissue reactions to it. All of the functionalized peptides self-assembled to form hydrogel scaffolds with a nanofibrous structure under physiological conditions. Compared with the RADA16-I and RAD-KAI scaffolds, the RAD-SNV and RAD-KPS scaffolds possessed better bioactivities for hdNPCs, which were characterized by their enhanced proliferation, migration, and ECM (collagen II, aggrecan, and sox-9) secretion. RAD-KPS was chosen over RAD-SNV as the most ideal scaffold material due to the cells' higher rate of expression of aggrecan both at the gene and protein level after 28 days of coculture. Moreover, in vivo analysis demonstrated that subcutaneously injected RAD-KPS degraded in vivo without invoking intense inflammation. Therefore, RAD-KPS is an ideal candidate scaffold for NP tissue engineering and holds great potential for NP regeneration.

Progressive dysphagia and neck pain due to diffuse idiopathic skeletal hyperostosis of the cervical spine: a case report and literature review.

Diffuse idiopathic skeletal hyperostosis (DISH) is considered an underdiagnosed and mostly asymptomatic nonprimary osteoarthritis. The etiology of DISH remains unknown and the validated diagnostic criteria are absent. This condition is still recognized radiologically only. Rarely, large projecting anterior osteophytes result in esophageal impingement and distortion leading to dysphagia. We report the case of progressive dysphagia and neck pain due to DISH of the cervical spine in a 70-year-old man, which was surgically removed with excellent postoperative results and complete resolution of symptoms. Imaging studies, surgical findings, and histopathological examinations were used to support the diagnosis. The patient was successfully treated with total excision of the anterior osteophytes with no evidence of recurrence 12 months after surgery. In this report, we also discuss the clinical features and perioperative considerations in combination with a literature review. Our patient illustrates that clinicians should be aware of this rare clinical manifestation as the presenting feature of DISH in cervical spine. Surgical decompression through osteophytectomy is effective for patients who fail conservative treatment.

Biological evaluation of human degenerated nucleus pulposus cells in functionalized self-assembling peptide nanofiber hydrogel scaffold.

Nucleus pulposus (NP) tissue engineering has been proposed as a novel biological treatment for early-stage intervertebral disc degeneration. In this study, a novel functional self-assembling peptide PKP was first designed by linking the short functional motif of bone morphogenetic protein-7 (BMP7) to the C-terminal of RADA16-I, and another new functional self-assembling peptide was obtained by mixing RKP with RADA16-I. Then, the biocompatibilities and bioactivities of RKP and RAD-RKP for human degenerated nucleus pulposus cells (hNPCs) were studied in vitro. Atomic force microscopy and scanning electron microscopy (SEM) confirmed that both RKP and RAD-RKP could self-assemble into three-dimensional (3D) nanofiber hydrogel scaffolds in a culture medium at 37°C. After the hNPCs were cultured in 3D scaffolds, both RKP and RAD-RKP exhibited reliable attachment and extremely low cytotoxicities (<14%), which were verified by SEM and cytotoxity assays, respectively. Our results also showed that the functional-based scaffolds could increase the proliferation and migration of hNPCs after 7 days compared with culture plates and pure RADA16-I. Quantitative real-time polymerase chain reaction demonstrated that the expressions of collagen II α1, Sox-9, and aggrecan were upregulated, while collagen I α1 was downregulated by functional-based scaffolds after 28 days. Furthermore, we also confirmed that RAD-RKP exhibited a higher hNPC proliferation, migration, and expression of Sox-9 and aggrecan compared with pure RKP. Therefore, the results of this study indicated that the BMP7 short motif-designed functional self-assembling peptide nanofiber hydrogels could be used as excellent scaffolds in NP tissue engineering, and RAD-RKP might have further potential application in human mild degenerated NP tissue regeneration.