Celecoxib alleviates nociceptor sensitization mediated by interleukin-1beta-primed annulus fibrosus cells.

PURPOSE: This study aims to analyze the effect of pro-inflammatory cytokine-stimulated human annulus fibrosus cells (hAFCs) on the sensitization of dorsal root ganglion (DRG) cells. We further hypothesized that celecoxib (cxb) could inhibit hAFCs-induced DRG sensitization. METHODS: hAFCs from spinal trauma patients were stimulated with TNF-α or IL-1ß. Cxb was added on day 2. On day 4, the expression of pro-inflammatory and neurotrophic genes was evaluated using RT-qPCR. Levels of prostaglandin E2 (PGE-2), IL-8, and IL-6 were measured in the conditioned medium (CM) using ELISA. hAFCs CM was then applied to stimulate the DRG cell line (ND7/23) for 6 days. Then, calcium imaging (Fluo4) was performed to evaluate DRG cell sensitization. Both spontaneous and bradykinin-stimulated (0.5 µM) calcium responses were analyzed. The effects on primary bovine DRG cell culture were performed in parallel to the DRG cell line model. RESULTS: IL-1ß stimulation significantly enhanced the release of PGE-2 in hAFCs CM, while this increase was completely suppressed by 10 µM cxb. hAFCs revealed elevated IL-6 and IL-8 release following TNF-α and IL-1ß treatment, though cxb did not alter this. The effect of hAFCs CM on DRG cell sensitization was influenced by adding cxb to hAFCs; both the DRG cell line and primary bovine DRG nociceptors showed a lower sensitivity to bradykinin stimulation. CONCLUSION: Cxb can inhibit PGE-2 production in hAFCs in an IL-1ß-induced pro-inflammatory in vitro environment. The cxb applied to the hAFCs also reduces the sensitization of DRG nociceptors that are stimulated by the hAFCs CM.

Anterior thoracolumbar column reconstruction with the vertebral body stent-safety and efficacy.

PURPOSE: The aim of this study was to assess safety and efficacy of vertebral body stenting (VBS) by analyzing (1) radiographic outcome, (2) clinical outcome, and (3) perioperative complications in patients with vertebral compression fractures treated with VBS at minimum 6-month follow-up. METHODS: In this retrospective cohort study, 78 patients (61 ± 14 [21-90] years; 67% female) who have received a vertebral body stent due to a traumatic, osteoporotic or metastatic thoracolumbar compression fracture at our hospital between 2012 and 2020 were included. Median follow-up was 0.9 years with a minimum follow-up of 6 months. Radiographic and clinical outcome was analyzed directly, 6 weeks, 12 weeks, 6 months postoperatively, and at last follow-up. RESULTS: Anterior vertebral body height of all patients improved significantly by mean 6.2 ± 4.8 mm directly postoperatively (p < 0.0001) and remained at 4.3 ± 5.1 mm at last follow-up compared to preoperatively (p < 0.0001). The fracture kyphosis angle of all patients improved significantly by mean 5.8 ± 6.9 degrees directly postoperatively (p < 0.0001) and remained at mean 4.9 ± 6.9 degrees at last follow-up compared to preoperatively (p < 0.0001). The segmental kyphosis angle of all patients improved significantly by mean 7.1 ± 7.6 degrees directly postoperatively (p < 0.0001) and remained at mean 2.8 ± 7.8 degrees at last follow-up compared to preoperatively (p = 0.03). Back pain was ameliorated from a preoperative median Numeric Rating Scale value of 6.5 to 3.0 directly postoperatively and further bettered to 1.0 six months postoperatively (p = 0.0001). Revision surgery was required in one patient after 0.4 years. CONCLUSION: Vertebral body stenting is a safe and effective treatment option for osteoporotic, traumatic and metastatic compression fractures.

Radiofrequency Neurotomy Does Not Cause Fatty Degeneration of the Lumbar Paraspinal Musculature in Patients with Chronic Lumbar Pain-A Retrospective 3D-Computer-Assisted MRI Analysis Using iSix Software.

OBJECTIVE: The present study aimed (1) to analyze the relative paraspinal autochthonous intramuscular fat volume before and after radiofrequency neurotomy (RFN) and (2) to compare it to the contralateral non-treated side. DESIGN: Retrospective cohort study. SETTING: Inselspital, University Hospital Bern, University of Bern. SUBJECTS: Twenty patients (59.60 ± 8.49 years; 55% female) with chronic low back pain, treated with RFN (L2/3-L5/S1) due to symptomatic facet joint syndrome (FCS) between 2008 and 2017 were included. METHODS: All patients received a magnetic resonance imaging (MRI) of the lumbar spine before and at a minimum of 6 months after RFN. The absolute (cm3) and relative (%) paraspinal muscle and fat volume was analyzed three-dimensionally on standard T2-MRI sequences using a newly developed software (iSix, Osiris plugin). Both sides were examined and allocated as treated or non-treated side. RESULTS: A total of 31 treated and 9 non-treated sides (Level L2/3-L5/S1) were examined. There were no differences in the relative paraspinal intramuscular fat volume before and at a median of 1.4 [0.9 - 2.6] years after RFN (P = .726). We found no differences in the relative fat volume between the treated and non-treated side before (P = .481) and after (P = .578) RFN. CONCLUSIONS: Our study shows that there are no differences in the paraspinal muscle/fat distribution after RFN. RFN of the medial branches for FCS does not seem to cause fatty degeneration of the lumbar paraspinal muscles as a sign of iatrogenic muscle denervation.

Asia Now Surpasses Europe in Spine Research Productivity: An Analysis From 1976-2020.

STUDY DESIGN: Bibliometric review. OBJECTIVE: This study aims to understand the worldwide research productivity trends in spine-related research over the past five decades. SUMMARY OF BACKGROUND DATA: Research productivity in the field of spine surgery has increased tremendously over the past decades. However, knowledge regarding the detailed regional disparity is limited. METHODS: We evaluated original research articles published in four prestigious journals on spine research (European Spine Journal, Journal of Neurosurgery: Spine, Spine, and The Spine Journal) from 1976 to 2020. For 1 year of each decade, the origin of the first and the senior author was assigned to their region of origin. For the year 2020, a detailed analysis of countries and states of origin was performed, and the number of articles was normalized by registered MDs per country (per 10,000 population). RESULTS: We included a total of 4436 articles and 8776 authors for analysis. From 1976 to 2020, the percentage of publications originating from North America decreased (77%-38%). In contrast, Asian contributions drastically increased (3%-36%), whereas articles originating from Europe only slightly raised (20%-22%). In 2020, the United States was the most productive country worldwide (34% with most articles from New York (19%), followed by China (16%) and Japan (10%). After normalization to registered MDs (per 10,000 population), the United States proved to have the highest number of articles. Besides this, India now ranked fourth and Egypt eighth in terms of the most productive countries per MDs. CONCLUSION: North America contributed the largest share of all articles published in the last five decades. Asia, which ranks second in 2020, has overtaken Europe. Normalization to registered MDs can be a helpful tool to reflect a country's research productivity more accurately.Level of Evidence: 3.

PMMA-Cement-PLIF Is Safe and Effective as a Single-Stage Posterior Procedure in Treating Pyogenic Erosive Lumbar Spondylodiscitis-A Single-Center Retrospective Study of 73 Cases.

BACKGROUND: Surgical treatment for erosive pyogenic spondylodiscitis of the lumbar spine is challenging as, following debridement of the intervertebral and bony abscess, a large and irregular defect is created. Sufficient defect reconstruction with conventional implants using a posterior approach is often impossible. Therefore, we developed the "Cement-PLIF", a single-stage posterior lumbar procedure, combining posterior lumbar interbody fusion (PLIF) with defect-filling using antibiotic-loaded polymethylmethacrylate (PMMA). This study first describes and evaluates the procedure's efficacy, safety, and infection eradication rate. Radiological implant stability, bone-regeneration, sagittal profile reconstruction, procedure-related complications, and pre-existing comorbidities were further analyzed. METHODS: A retrospective cohort study analyzing 73 consecutive patients with a minimum of a one-year follow-up from 2000-2017. Patient-reported pain levels and improvement in infectious serological parameters evaluated the clinical outcome. Sagittal profile reconstruction, anterior bone-regeneration, and posterior fusion were analyzed in a.p. and lateral radiographs. A Kaplan-Meier analysis was used to determine the impact of pre-existing comorbidities on mortality. Pre-existing comorbidities were quantified using the Charlson-Comorbidity Index (CCI). RESULTS: Mean follow-up was 3.3 (range: 1-16; ±3.2) years. There was no evidence of infection persistence in all patients at the one-year follow-up. One patient underwent revision surgery for early local infection recurrence (1.4%). Five (6.9%) patients required an early secondary intervention at the same level due to minor complications. Radiological follow-up revealed implant stability in 70/73 (95.9%) cases. Successful sagittal reconstruction was demonstrated in all patients (p < 0.001). There was a significant correlation between Kaplan-Meier survival and the number of pre-existing comorbidities (24-months-survival: CCI ≤ 3: 100%; CCI ≥ 3: 84.6%; p = 0.005). CONCLUSIONS: The Cement-PLIF procedure for pyogenic erosive spondylodiscitis is an effective and safe treatment as evaluated by infection elimination, clinical outcome, restoration, and maintenance of stability and sagittal alignment.

The function of CD146 in human annulus fibrosus cells and mechanism of the regulation by TGF-ß.

The mouse outer annulus fibrosus (AF) was previously shown to contain CD146+ AF cells, while in vitro culture and exposure to transforming growth factor-beta (TGF-ß) further increased the expression of CD146. However, neither the specific function of CD146 nor the underlying mechanism of TGF-ß upregulation of CD146+ AF cells have been elucidated yet. In the current study, CD146 expression and its role in cultured human AF cells was investigated studying the cells' capacity for matrix contraction and gene expression of functional AF markers. In addition, TGF-ß pathways were blocked by several pathway inhibitors and short hairpin RNAs (shRNAs) targeting SMAD and non-SMAD pathways to investigate their involvement in TGF-ß-induced CD146 upregulation. Results showed that knockdown of CD146 led to reduction in AF cell-mediated collagen gel contraction, downregulation of versican and smooth muscle protein 22α (SM22α), and upregulation of scleraxis. TGF-ß-induced CD146 upregulation was significantly blocked by inhibition of TGF-ß receptor ALK5, and partially inhibited by shRNA against SMAD2 and SMAD4 and by an Protein Kinase B (AKT) inhibitor. Interestingly, the inhibition of extracellular signal-regulated kinases (ERK) pathway induced CD146 upregulation. In conclusion, CD146 was shown to be crucial to maintain the cell contractility of human AF cells in vitro. Furthermore, TGF-ß upregulated CD146 via ALK5 signaling cascade, partially through SMAD2, SMAD4, and AKT pathway, whereas, ERK was shown to be a potential negative modulator. Our findings suggest that CD146 can potentially be used as a functional marker in AF repair strategies.

Improved estimates of strength and stiffness in pathologic vertebrae with bone metastases using CT-derived bone density compared with radiographic bone lesion quality classification.

OBJECTIVE: The aim of this study was to compare the ability of 1) CT-derived bone lesion quality (classification of vertebral bone metastases [BM]) and 2) computed CT-measured volumetric bone mineral density (vBMD) for evaluating the strength and stiffness of cadaver vertebrae from donors with metastatic spinal disease. METHODS: Forty-five thoracic and lumbar vertebrae were obtained from cadaver spines of 11 donors with breast, esophageal, kidney, lung, or prostate cancer. Each vertebra was imaged using microCT (21.4 µm), vBMD, and bone volume to total volume were computed, and compressive strength and stiffness experimentally measured. The microCT images were reconstructed at 1-mm voxel size to simulate axial and sagittal clinical CT images. Five expert clinicians blindly classified the images according to bone lesion quality (osteolytic, osteoblastic, mixed, or healthy). Fleiss' kappa test was used to test agreement among 5 clinical raters for classifying bone lesion quality. Kruskal-Wallis ANOVA was used to test the difference in vertebral strength and stiffness based on bone lesion quality. Multivariable regression analysis was used to test the independent contribution of bone lesion quality, computed vBMD, age, gender, and race for predicting vertebral strength and stiffness. RESULTS: A low interrater agreement was found for bone lesion quality (κ = 0.19). Although the osteoblastic vertebrae showed significantly higher strength than osteolytic vertebrae (p = 0.0148), the multivariable analysis showed that bone lesion quality explained 19% of the variability in vertebral strength and 13% in vertebral stiffness. The computed vBMD explained 75% of vertebral strength (p < 0.0001) and 48% of stiffness (p < 0.0001) variability. The type of BM affected vBMD-based estimates of vertebral strength, explaining 75% of strength variability in osteoblastic vertebrae (R2 = 0.75, p < 0.0001) but only 41% in vertebrae with mixed bone metastasis (R2 = 0.41, p = 0.0168), and 39% in osteolytic vertebrae (R2 = 0.39, p = 0.0381). For vertebral stiffness, vBMD was only associated with that of osteoblastic vertebrae (R2 = 0.44, p = 0.0024). Age and race inconsistently affected the model's strength and stiffness predictions. CONCLUSIONS: Pathologic vertebral fracture occurs when the metastatic lesion degrades vertebral strength, rendering it unable to carry daily loads. This study demonstrated the limitation of qualitative clinical classification of bone lesion quality for predicting pathologic vertebral strength and stiffness. Computed CT-derived vBMD more reliably estimated vertebral strength and stiffness. Replacing the qualitative clinical classification with computed vBMD estimates may improve the prediction of vertebral fracture risk.

Systematic Review and Meta-Analysis of 3 Treatment Arms for Vertebral Compression Fractures: A Comparison of Improvement in Pain, Adjacent-Level Fractures, and Quality of Life Between Vertebroplasty, Kyphoplasty, and Nonoperative Management.

BACKGROUND: Osteoporotic vertebral fractures (OVFs) have become increasingly common, and previous nonrandomized and randomized controlled trials (RCTs) have compared the effects of cement augmentation versus nonoperative management on the clinical outcome. This meta-analysis focuses on RCTs and the calculated differences between cement augmentation techniques and nonsurgical management in outcome (e.g., pain reduction, adjacent-level fractures, and quality of life [QOL]). METHODS: A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, and the following scientific search engines were used: MEDLINE, Embase, Cochrane, Web of Science, and Scopus. The inclusion criteria included RCTs that addressed different treatment strategies for OVF. The primary outcome was pain, which was determined by a visual analog scale (VAS) score; the secondary outcomes were the risk of adjacent-level fractures and QOL (as determined by the EuroQol-5 Dimension [EQ-5D] questionnaire, the Oswestry Disability Index [ODI], the Quality of Life Questionnaire of the European Foundation for Osteoporosis [QUALEFFO], and the Roland-Morris Disability Questionnaire [RDQ]). Patients were assigned to 3 groups according to their treatment: vertebroplasty (VP), kyphoplasty (KP), and nonoperative management (NOM). The short-term (weeks), midterm (months), and long-term (>1 year) effects were compared. A random effects model was used to summarize the treatment effect, including I2 for assessing heterogeneity and the revised Cochrane risk-of-bias 2 (RoB 2) tool for assessment of ROB. Funnel plots were used to assess risk of publication bias. The log of the odds ratio (OR) between treatments is reported. RESULTS: After screening of 1,861 references, 53 underwent full-text analysis and 16 trials (30.2%) were included. Eleven trials (68.8%) compared VP and NOM, 1 (6.3%) compared KP and NOM, and 4 (25.0%) compared KP and VP. Improvement of pain was better by 1.31 points (95% confidence interval [CI], 0.41 to 2.21; p < 0.001) after VP when compared with NOM in short-term follow-up. Pain effects were similar after VP and KP (midterm difference of 0.0 points; 95% CI, -0.25 to 0.25). The risk of adjacent-level fractures was not increased after any treatment (log OR, -0.16; 95% CI, -0.83 to 0.5; NOM vs. VP or KP). QOL did not differ significantly between the VP or KP and NOM groups except in the short term when measured by the RDQ. CONCLUSIONS: This meta-analysis provides evidence in favor of the surgical treatment of OVFs. Surgery was associated with greater improvement of pain and was unrelated to the development of adjacent-level fractures or QOL. Although improvements in sagittal balance after surgery were poorly documented, surgical treatment may be warranted if pain is a relevant problem. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Metoclopramide treatment blocks CD93-signaling-mediated self-renewal of chronic myeloid leukemia stem cells.

Self-renewal is a key characteristic of leukemia stem cells (LSCs) responsible for the development and maintenance of leukemia. In this study, we identify CD93 as an important regulator of self-renewal and proliferation of murine and human LSCs, but not hematopoietic stem cells (HSCs). The intracellular domain of CD93 promotes gene transcription via the transcriptional regulator SCY1-like pseudokinase 1 independently of ligation of the extracellular domain. In a drug library screen, we identify the anti-emetic agent metoclopramide as an efficient blocker of CD93 signaling. Metoclopramide treatment reduces murine and human LSCs in vitro and prolongs survival of chronic myeloid leukemia (CML) mice through downregulation of pathways related to stemness and proliferation in LSCs. Overall, these results identify CD93 signaling as an LSC-specific regulator of self-renewal and proliferation and a targetable pathway to eliminate LSCs in CML.

Conventional finite element models estimate the strength of metastatic human vertebrae despite alterations of the bone's tissue and structure.

INTRODUCTION: Pathologic vertebral fractures are a major clinical concern in the management of cancer patients with metastatic spine disease. These fractures are a direct consequence of the effect of bone metastases on the anatomy and structure of the vertebral bone. The goals of this study were twofold. First, we evaluated the effect of lytic, blastic and mixed (both lytic and blastic) metastases on the bone structure, on its material properties, and on the overall vertebral strength. Second, we tested the ability of bone mineral content (BMC) measurements and standard FE methodologies to predict the strength of real metastatic vertebral bodies. METHODS: Fifty-seven vertebral bodies from eleven cadaver spines containing lytic, blastic, and mixed metastatic lesions from donors with breast, esophageal, kidney, lung, or prostate cancer were scanned using micro-computed tomography (µCT). Based on radiographic review, twelve vertebrae were selected for nanoindentation testing, while the remaining forty-five vertebrae were used for assessing their compressive strength. The µCT reconstruction was exploited to measure the vertebral BMC and to establish two finite element models. 1) a micro finite element (µFE) model derived at an image resolution of 24.5 µm and 2) homogenized FE (hFE) model derived at a resolution of 0.98 mm. Statistical analyses were conducted to measure the effect of the bone metastases on BV/TV, indentation modulus (Eit), ratio of plastic/total work (WPl/Wtot), and in vitro vertebral strength (Fexp). The predictive value of BMC, µFE stiffness, and hFE strength were evaluated against the in vitro measurements. RESULTS: Blastic vertebral bodies exhibit significantly higher BV/TV compared to the mixed (p = 0.0205) and lytic (p = 0.0216) vertebral bodies. No significant differences were found between lytic and mixed vertebrae (p = 0.7584). Blastic bone tissue exhibited a 5.8% lower median Eit (p< 0.001) and a 3.3% lower median Wpl/Wtot (p<0.001) compared to non-involved bone tissue. No significant differences were measured between lytic and non-involved bone tissues. Fexp ranged from 1.9 to 13.8 kN, was strongly associated with hFE strength (R2=0.78, p< 0.001) and moderately associated with BMC (R2=0.66, p< 0.001) and µFE stiffness (R2=0.66, p< 0.001), independently of the lesion type. DISCUSSION: Our findings show that tumour-induced osteoblastic metastases lead to slightly, but significantly lower bone tissue properties compared to controls, while osteolytic lesions appear to have a negligible impact. These effects may be attributed to the lower mineralization and woven nature of bone forming in blastic lesions whilst the material properties of bone in osteolytic vertebrae appeared little changed. The moderate association between BMC- and FE-based predictions to fracture strength suggest that vertebral strength is affected by the changes of bone mass induced by the metastatic lesions, rather than altered tissue properties. In a broader context, standard hFE approaches generated from CTs at clinical resolution are robust to the lesion type when predicting vertebral strength. These findings open the door for the development of FE-based prediction tools that overcomes the limitations of BMC in accounting for shape and size of the metastatic lesions. Such tools may help clinicians to decide whether a patient needs the prophylactic fixation of an impending fracture.

Direct anterior decompression of L4 and L5 nerve root in sacral fractures using the pararectus approach: a technical note.

PURPOSE: To describe a new surgical technique for neurolysis and decompression of L4 and L5 nerve root entrapment after vertical sacral fractures via the pararectus approach for acetabular fractures, and to present four case examples. PATIENTS AND METHODS: We retrospectively evaluated four patients suffering radiculopathy from entrapment of the L4 or L5 nerve root in vertical sacral fractures between January and December 2016. The mean follow-up period after surgery was 18 (range 7-27) months. All patients underwent direct decompression and neurolysis of the L4 and L5 nerve roots via the single-incision, intrapelvic, extraperitoneal pararectus approach. RESULTS: In all patients, the L4 and L5 nerve root was successfully visualized and decompressed, proving feasibility of the pararectus approach for this indication. No patient presented with a neural tear. Complete neurologic recovery was present in one patient at last follow-up; two patients had incomplete recovery of their radiculopathy; and one patient had no improvement after nerve root decompression. CONCLUSIONS: The pararectus approach allows for sufficient visualisation and direct decompression and neurolysis of the L4 and L5 nerve root entrapped in vertical sacral fractures. Although neurologic recovery was not achieved in all patients in this small case series, the approach may be a suitable alternative to posterior approaches and other anterior approaches such as the lateral window of the ilioinguinal approach.

First Clinical Experience with a Carbon Fibre Reinforced PEEK Composite Plating System for Anterior Cervical Discectomy and Fusion.

Carbon fibre reinforced polyether ether ketone (CFR-PEEK) is a suitable material to replace metal implants in orthopaedic surgery. The radiolucency of CFR-PEEK allows an optimal visualisation of the bone and soft tissue structures. We aimed to assess the performance and radiological and clinical outcomes of anterior cervical discectomy and fusion (ACDF) with CFR-PEEK anterior cervical plating (ACP) under first use clinical conditions. We retrospectively studied the prospectively-collected data of 42 patients who underwent ACDF with CFR-PEEK ACP between 2011 and 2016. We assessed clinical outcome (Odom's criteria, complications) and radiological parameters (global and segmental cervical lordosis, Bridwell score for fusion, adjacent segment degeneration) preoperatively, immediately post-operatively, and after a 12-month follow-up period. Patients' satisfaction was excellent, good, fair, and poor in 12, 19, 3, and 1 patients, respectively. Two patients developed dysphagia. No hardware failure occurred. Compared with preoperative radiographs, we observed a gain of global cervical lordosis and segmental lordosis (7.4 ± 10.1 and 5.6 ± 7.1 degrees, respectively) at the 12-month follow-up. Bridwell IF grades I, II, and III were observed in 22, 6, and 7 patients, respectively. The 12-month adjacent segment degeneration-free and adjacent segment disease-free survival rates were 93.1% and 96.3%, respectively. We observed a dysphagia rate of 5.7% and a reoperation rate of 4.8%. In conclusion, CFR-PEEK ACP shows positive outcomes in terms of implant safety, restoration of cervical lordosis, and functional recovery, and is suitable for ACDF.

Ventral Surgical Approach for an Intervertebral Disc Degeneration and Regeneration Model in Sheep Cervical Spine: Anatomic Technical Description, Strengths and Limitations.

OBJECTIVE: Sheep are used as a large animal model for intervertebral disc research. However, for the ovine ventral surgical approach to the cervical disc, limited descriptions exist. We, therefore, give a detailed in vivo anatomical description of this approach in sheep for the use in intervertebral disc regeneration and degeneration models to increase the reproducibility of such interventions. MATERIALS AND METHODS: Eighteen female Swiss white alpine sheep, with an age range of 2 to 4 years, were used. A ventral surgical access was performed to establish defined intervertebral disc punch defect from cervical levels C3/4 to C5/6. Cervical levels C2/3 and C6/7 were used as negative controls. Intraoperative findings, radiographical controls and postoperative clinical follow-up were documented and collected for this clinical report. RESULTS: All sheep recovered rapidly from the surgical intervention. Two sheep developed wound seroma, which resorbed spontaneously. Two further sheep showed wound dehiscence within 3 days after surgery, which had to be revised. No clinical wound infections occurred and all sheep healed well and did not show any side effects related to the surgical procedure. CONCLUSION: The ventral surgical access to the ovine cervical spine is a safe and reliable procedure. The advantage of the cervical intervertebral disc is the easier surgical access and the increased disc height compared to the sheep lumbar spine. Since the ovine cervical intervertebral disc shows a high grade of similarities (e.g. molecular characteristics) compared to human discs, it is a promising degeneration and regeneration model for disc diseases.

Spinal injuries in airborne accidents: a demographic overview of 148 patients in a level-1 trauma center.

PURPOSE: The purpose of this study was to investigate the type and severity of spinal injury in airborne sports, as well as patients demographics in this unique set of athletes. Paragliding is one of the most popular airborne sports in Switzerland, which thought to be no less dangerous with a high potential for spinal injury. Few studies on spinal column injuries have been performed in these high-risk athletes with only inconsistent findings. METHODS: Patient charts were analyzed for all airborne sports injuries affecting the spine from 2010 to 2017 at a level-1 trauma center in Switzerland. To classify the injuries, we used the newest AOSpine classification, ASIA-grading and the injury severity score (ISS). In total, 235 patients were admitted to the emergency department due to an airborne injury. A total of 148 patients (148/235, 63.0%) which were predominantly male (125/235, 84.5%) at a mean age of 39.4 years suffered 334 spinal fractures and 5 spinal contusions. The mean ISS was 17.3, and the L1 vertebra was most commonly affected (47.6% of cases, 68/148). RESULTS: A total of 78 patients (54.5% or 78/148) required spine surgery due to instability or neurological deficits (31/148 patients; 20.9%). Concomitant injuries were identified in 64.2% of cases (n = 95). CONCLUSION: Due to the increasing popularity of airborne sports, age of patients and severity of injuries (ISS) increased compared with the literature. The thoracolumbal spine is at especially high risk. To prevent further complications, the treatment procedure has to be sought carefully and algorithm should be introduced in clinics to avoid delay in diagnostics and surgery. LEVEL OF EVIDENCE: III, retrospective comparative study. These slides can be retrieved under Electronic Supplementary Material.

Periprosthetic Infection: Major Cause of Early Failure of Primary and Revision Total Knee Arthroplasty.

Revision total knee arthroplasty (RTKA) represents an effective treatment for failed TKA, but with less favorable outcomes. Considering the technical complexity and economic burden of RTKA procedures, it is mandatory to investigate current mechanisms and predictors for RTKA failure. The objective of this study is to evaluate the survivorship and determine the predominant causes of failure of RTKA. A total of 146 patients undergoing RTKA between 2003 and 2013 were identified from the institutional database. Revision was defined as surgery in which the whole prostheses (inlay and both femoral and tibial components) required exchange. Median follow-up was 6.3 ± 2.7 years (range: 2.2-10). Patient demographics, year of primary implantation, reasons for revision surgery, implant type, pain, knee mobility, systemic or local postoperative complications, and treatment of the complications were recorded and evaluated. Infection was a major cause of failure followed by aseptic loosening, instability, pain, malalignment, and inlay wear. Following RTKA, Knee Society Score (KSS) (knee score and functional score) demonstrated a significant improvement (p < 0.05). No significant difference in flexion, extension deficit, and KSS was detected between aseptic and septic primary TKAs preoperatively and following first RTKA. Reinfection rate of the septic primary TKAs was 5%. Infection was the major cause of a second revision, reaching as high as 50% in all cases. The results of this study support that septic failure of a primary TKA is likely to occur within the first 2 years following implantation. Septic failure of primary TKA does not influence survival of the revision prosthesis.

First Results of a New Vacuum Plasma Sprayed (VPS) Titanium-Coated Carbon/PEEK Composite Cage for Lumbar Interbody Fusion.

The aim of this study was to assess the performance of a new vacuum plasma sprayed (VPS) titanium-coated carbon/polyetheretherketone (PEEK) cage under first use clinical conditions. Forty-two patients who underwent a one or two segment transforaminal lumbar interbody fusion (TLIF) procedure with a new Ca/PEEK composite cage between 2012 and 2016 were retrospectively identified by an electronic patient chart review. Fusion rates (using X-ray), patient's satisfaction, and complications were followed up for two years. A total of 90.4% of the patients were pain-free and satisfied after a follow up (FU) period of 29.1 ± 9 (range 24-39) months. A mean increase of 3° in segmental lordosis in the early period (p = 0.002) returned to preoperative levels at final follow-ups. According to the Bridwell classification, the mean 24-month G1 fusion rate was calculated as 93.6% and the G2 as 6.4%. No radiolucency around the cage (G3) or clear pseudarthrosis could be seen (G4). In conclusion, biological properties of the inert, hydrophobic surface, which is the main disadvantage of PEEK, can be improved with VPS titanium coating, so that the carbon/PEEK composite cage, which has great advantages in respect of biomechanical properties, can be used safely in TLIF surgery. High fusion rates, good clinical outcome, and low implant-related complication rates without the need to use rhBMP or additional iliac bone graft can be achieved.

Most Influential Literature in Spinal Tuberculosis: A Global Disease Without Global Evidence.

STUDY DESIGN: Bibliometric review of the literature. OBJECTIVE: This bibliometric analysis aims to give an overview of the most influential academic literature written on spinal tuberculosis. METHODS: All databases included in the Thomson Reuters Web of Knowledge were searched for the most influential publications in spinal tuberculosis. The most cited articles published between 1950 and 2015, with the main focus on orthopedic surgery, were identified using a multistep approach, and a total of 100 articles were included. The publications were then analyzed in this bibliometric analysis. RESULTS: The number of citations ranged from 243 to 36, with an average of 77.11. The articles were published in 34 different journals, and the studies were conducted in 20 different countries. The top 3 countries, India, the United States, and China, published a total of 51% (n = 51) of all articles. Low-burden countries produced 60% (n = 60) of all articles in our list. African centers produced only 4% (n = 4) of all included articles. CONCLUSIONS: Indian and Chinese researchers dominate evidence in spinal tuberculosis. Other areas with high disease burden, such as Africa, do not feature. Most publications are retrospective studies with a low level of evidence.

Thermic effect on metal body piercing by electrosurgery: An ex vivo study on pig skin and bovine liver.

BACKGROUND: Piercings are placed at different body sites often invisible to medical staff. They may cause additional injuries in trauma and emergency surgery by electro-cautery. OBJECTIVE: To clarify whether electrosurgery will have a direct damaging effect to the skin around a pierced skin area. METHODS: Metallic piercings were fixed at defined distances from the neutral and active electrode on abdominal pig skin. The distance of the active electrode was reduced by 5 mm increments to 0. The respective increases in temperature were determined with a thermal camera. A macroscopic and histological analysis of the area around the piercing to detect thermal damage was carried out. RESULTS: Significant increases in temperature and visible changes in the tissue around the piercing only occurred when the active electrode was in direct contact with the piercing (increase of 47.3∘C). Electro-cautery in distance of 5 to 10 mm to the piercing showed only temperature increases of less than 5∘C. CONCLUSIONS: If metallic piercings are not directly touched by the active electrode and the distance is more than 5-10 mm, no clinically relevant effect is created on the tissue in direct proximity to the piercings by electro-cautery. In an emergency surgery situation, a piercing not fixed in direct proximity to the surgical field may likely be ignored.

Epidemiology of Musculoskeletal Tuberculosis in an Area with High Disease Prevalence.

STUDY DESIGN: Retrospective observational study. PURPOSE: The aim of this study was to assess the distribution of age and site of infection in patients with musculoskeletal tuberculosis (TB) and determine the number of TB/human immunodeficiency virus (HIV) coinfections as well as the incidence of multidrugresistant (MDR) TB. OVERVIEW OF LITERATURE: Of all TB cases, 1%-3% show skeletal system involvement and 30% are HIV coinfected. Although the reported distribution of skeletal TB is majorly in the spine, followed by the hip, knee, and foot/ankle, the epidemiology of extrapulmonary TB and especially musculoskeletal TB remains largely unknown, particularly in areas with a high prevalence of the disease. METHODS: This is a retrospective study of a consecutive series of patients admitted to a tertiary care facility in an area with the highest prevalence of TB worldwide. TB was confirmed on tissue biopsy with polymerase chain reaction testing (Xpert for Mycobacterium tuberculosis and rifampicin resistance), culturing, or histological analysis. Data were analyzed regarding demographic information, location of the disease, HIV coinfections, and drug resistance. RESULTS: In all, 125 patients (44 children; 35%) with a mean age of 27 years (range, 1-78 years) were included. Age peaks were observed at 5, 25, and 65 years. Spinal disease was evident in 98 patients (78%). There were 66 HIV-negative (53%) and 29 (23%) HIVpositive patients, and in 30 (24%), the HIV status was unknown. Five patients (4%) showed MDR TB. CONCLUSIONS: The age distribution was trimodal, spinal disease was predominant, MDR TB rate in our cohort was high, and a large portion of TB patients in our hospital were HIV coinfected. Hence, spinal services with sufficient access to operating facilities are required for tertiary care facilities in areas with a high TB prevalence.

Outcome measures in clinical ACL studies: an analysis of highly cited level I trials.

PURPOSE: Clinical research in the area of anterior cruciate ligament (ACL) injury has shown substantial growth during the last decade. This was accompanied by the establishment of a wide range of outcome measures used to address the demands of clinical studies. The aim of this study was to evaluate outcome measures reported by highly cited level I trials in ACL research and identify factors influencing citation metrics. METHODS: The database of the Institute for Scientific Information (ISI) was utilized to screen journals under the subject categories "Orthopaedics", "Sports Sciences", "Radiology" and "General medicine" for the 50 most cited level I ACL trials based on predefined inclusion criteria. Metadata, citation metrics and outcome measures were extracted for each article. Frequencies of reported outcome measures were calculated, and a multiple linear regression model applied to identify factors influencing citation metrics. RESULTS: Two independent outcome measures demonstrated an influence on acquisition of citations including: 1-report of the pivot-shift test and 2-inclusion of the Knee Injury and Osteoarthritis Outcome (KOOS) score. Furthermore, highly cited ACL trials frequently reported KT-1000 measures of anterior translation, range of motion (ROM), graft failure, Lysholm, Tegner and subjective International Knee Documentation (IKDC) scores. CONCLUSION: This analysis reflects on the outcome measures utilized in highly cited level I trials impacting the field of ACL research. It also identifies factors likely to influence acquisition of citations. This is of both clinical and academic relevance when choosing appropriate measures for post-operative outcome evaluation after ACL surgery. LEVEL OF EVIDENCE: I.