Neurological complications in oncological and degenerative spine surgery represent one of the most feared risks of these procedures. Multimodal intraoperative neurophysiological monitoring (IONM) mainly uses methods to detect changes in the patient's neurological status in a timely manner, thus allowing actions that can reverse neurological deficits before they become irreversible. The utopian goal of spinal surgery is the absence of neurological complications while the realistic goal is to optimize the responses to changes in neuromonitoring such that permanent deficits occur less frequently as possible. In 2014, an algorithm was proposed in response to changes in neuromonitoring for deformity corrections in spinal surgery. There are several studies that confirm the positive impact that a checklist has on care. The proposed checklist has been specifically designed for interventions on stable columns which is significantly different from oncological and degenerative surgery. The goal of this project is to provide a checklist for oncological and degenerative spine surgery to improve the quality of care and minimize the risk of neurological deficit through the optimization of clinical decision-making during periods of intraoperative stress or uncertainty. After a literature review on risk factors and recommendations for responding to IONM changes, 3 surveys were administered to 8 surgeons with experience in oncological and degenerative spine surgery from 5 hospitals in Italy. In addition, anesthesiologists, intraoperative neuro-monitoring teams, operating room nurses participated. The members participated in the optimization and final drafting of the checklist. The authors reassessed and modified the checklist during 3 meetings over 9 months, including a clinical validation period using a modified Delphi process. A checklist containing 28 items to be considered in responding to the changes of the IONM was created. The checklist was submitted for inclusion in the new recommendations of the Italian Society of Clinical Neurophysiology (SINC) for intraoperative neurophysiological monitoring. The final checklist represents the consensus of a group of experienced spine surgeons. The checklist includes the most important and high-performance items to consider when responding to IONM changes in patients with an unstable spine. The implementation of this checklist has the potential to improve surgical outcomes and patient safety in the field of spinal surgery

Introduction. To develop an international guideline (AOGO) about use of osteobiologics in Anterior Cervical Discectomy and Fusion (ACDF) for treating degenerative spine conditions. Method. The guideline development process was guided by AO Spine Knowledge Forum Degenerative (KF Degen) and followed the Guideline International Network McMaster Guideline Development Checklist. The process involved 73 participants with expertise in degenerative spine diseases and surgery from 22 countries. Fifteen systematic reviews were conducted addressing respective key topics and evidence were collected. The methodologist compiled the evidence into GRADE Evidence-to-Decision frameworks. Guideline panel members judged the outcomes and other criteria and made the final recommendations through consensus. Result. Five conditional recommendations were created. A conditional recommendation is about the use of allograft, autograft or a cage with an osteobiologic in primary ACDF surgery. Other conditional recommendations are about use of osteobiologic for single or multi-level ACDF, and for hybrid construct surgery. It is suggested that surgeons use other osteobiologics rather than human bone morphogenetic protein-2 in common clinical situations. Surgeons are recommended to choose one graft over another or one osteobiologic over another primarily based on clinical situation, and the costs and availability of the materials. Conclusion. This AOGO guideline is the first to provide recommendations for the use of osteobiologics in ACDF. Despite the comprehensive searches for evidence, there were few studies completed with small sample sizes and primarily as case series with inherent risks of bias. Therefore high quality clinical evidence is demanded to improve the guideline

Introduction. Intervertebral disc degeneration (IDD) is a progressive process affecting all disc tissues, namely the nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplates (CEPs). Several cell-based therapies have been proposed to replenish the disc cell population and promote tissue regeneration. However, cell-free therapeutics have been increasingly explored due to potentially higher advantages and cost-effectiveness compared to cell transplantation. Recently, extracellular vesicles (EVs) isolated from healthy Tie2. +. -NP cells (NPCs) have shown promising regenerative outcomes on degenerative NPCs (dNPCs). The aim of this study was to assess the effect of such EVs on all disc cell types, including AF cells (AFCs) and CEP cells (CEPCs), compared to EVs isolated from bone-marrow derived mesenchymal stromal cells (BM-MSCs). Method. NPCs harvested from young donors underwent an optimized culture protocol to maximize Tie2 expression (NPCs. Tie2+. ). BM-MSCs were retrieved from a commercial cell line or harvested during spine surgery procedures. EV characterization was performed via particle size analysis (qNano), expression of EV markers (Western blot), and transmission electron microscopy. dNPCs, AFCs, and CEPCs were isolated from surgical specimens of patients affected by IDD, culture-expanded, and treated with NPCs. Tie2+. -EVs or BM-MSC-EVs ± 10 ng/mL IL-1b. EV uptake was assessed with PKH26 staining of EVs under confocal microscopy. Cell proliferation and viability were assessed with the CCK-8 assay. Result. Upon characterization, isolated EVs exhibited the typical exosomal characteristics. NPCs. Tie2+. -EVs and BM-MSC-EVs uptake was successfully observed in all dNPCs, AFCs, and CEPCs. Both EV products significantly increased dNPC, AFC, and CEPC viability, especially in samples treated with NPCs. Tie2+. -EVs. Conclusion. NPCs. Tie2+. -EVs demonstrated to significantly stimulate the proliferation and viability of degenerative cells isolated from all disc tissues. Rather than the sole NP, EVs isolated by committed progenitors physiologically residing within the disc may exert their regenerative effects on the whole organ, thus possibly constituting the basis for a new therapy for IDD

Critical shoulder angle (CSA), lateral acromial angle (LAA), and acromion index (AI) are common radiologic parameters used to distinguish between patients with rotator cuff tears (RCT) and those with an intact rotator cuff. This study aims to assess the predictive power of these parameters in degenerative RCT. This retrospective study included data from 92 patients who were divided into two groups: the RCT group, which included 47 patients with degenerative full-thickness supraspinatus tendon tears, and a control group of 45 subjects without tears. CSA, AI, and LAA measurements from standardized true anteroposterior radiographs were independently derived and analyzed by two orthopedic surgeons. Receiver operating characteristic (ROC) analyses were performed to determine the cutoff values. No significant differences were found between patients in the RCT and control groups in age (p = 0.079), gender (p = 0.804), or injury side (p = 0.552). Excellent inter-observer reliability was seen for CSA, LAA, and AI values. Mean CSA (38.1°) and AI (0.72) values were significantly larger in the RCT group than in the control group (34.56° and 0.67°, respectively, p < 0.001) with no significant difference between groups for LAA (RCT, 77.99° vs. control, 79.82°; p = 0.056). ROC analysis yielded an area under the curve (AUC) of 0.815 for CSA with a cutoff value of 37.95°, and CSA was found to be the strongest predictor of the presence of a RCT, followed by AI with an AUC of 0.783 and a cutoff value of 0.705. We conclude that CSA and AI may be useful predictive factors for degenerative RCT in the Turkish population

Intervertebral disc degeneration can lead to physical disability and significant pain, while the present therapeutics still fail to biochemically and biomechanically restore the tissue. Stem cell-based therapy in treating intervertebral disc (IVD) degeneration is promising while transplanting cells alone might not be adequate for effective regeneration. Recently, gene modification and 3D-printing strategies represent promising strategies to enhanced therapeutic efficacy of MSC therapy. In this regard, we hypothesized that the combination of thermosensitive chitosan hydrogel and adipose derived stem cells (ADSCs) engineered with modRNA encoding Interleukin − 4 (IL-4) can inhibit inflammation and promote the regeneration of the degenerative IVD. Rat ADSCs were acquired from adipose tissue and transfected with modRNAs. First, the kinetics and efficacy of modRNA-mediated gene transfer in mouse ADSCs were analyzed in vitro. Next, we applied an indirect co-culture system to analyze the pro-anabolic potential of IL-4 modRNA engineered ADSCs (named as IL-4-ADSCs) on nucleus pulposus cells. ModRNA transfected mouse ADSCs with high efficiency and the IL-4 modRNA-transfected ADSCs facilitated burst-like production of bio-functional IL-4 protein. In vitro, IL-4-ADSCs induced increased anabolic markers expression of nucleus pulposus cells in inflammation environment compared to untreated ADSCs. These findings collectively supported the therapeutic potential of the combination of thermosensitive chitosan hydrogel and IL-4-ADSCs for intervertebral disc degeneration management. Histological and in vivo validation are now being conducted

The relationship of degeneration to symptoms has been questioned. MRI detects apparently similar disc degeneration and degenerative changes in subjects both with and without back pain. We aimed to overcome these problems by re-annotating MRIs from asymptomatic and symptomatic groups onto the same grading system. We analysed disc degeneration in pre-existing large MRI datasets. Their MRIs were all originally annotated on different scales. We re-annotated all MRIs independent of their initial grading system, using a verified, rapid automated MRI annotation system (SpineNet) which reported degeneration on the Pfirrmann (1-5) scale, and other degenerative features (herniation, endplate defects, marrow signs, spinal stenosis) as binary present/absent. We compared prevalence of degenerative features between symptomatics and asymptomatics. Pfirrmann degeneration grades in relation to age and spinal level were very similar for the two independent groups of symptomatics over all ages and spinal levels. Severe degenerative changes were significantly more prevalent in discs of symptomatics than asymptomatics in the caudal but not the rostral lumbar discs in subjects < 60 years. We found high co-existence of degenerative features in both populations. Degeneration was minimal in around 30% of symptomatics < 50 years. We confirmed age and disc level are significant in determining imaging differences between asymptomatic and symptomatic populations and should not be ignored. Automated analysis, by rapidly combining and comparing data from existing groups with MRIs and information on LBP, provides a way in which epidemiological and ‘big data’ analysis could be advanced without the expense of collecting new groups

Abstract. Objective. Meta-analysis of clinical trials highlights that non-operative management of degenerative knee meniscal tears is as effective as surgical management. Surgical guidelines though support arthroscopic partial meniscectomy which remains common in NHS practice. Physiotherapists are playing an increasing role in triage of such patients though it is unclear how this influences clinical management and patient outcomes. Methods. A 1-year cohort (July 2019–June 2020) of patients presenting with MRI confirmed degenerative meniscal tears to a regional orthopaedic referral centre (3× ESP physiotherapists) was identified. Initial clinical management was obtained from medical records alongside subsequent secondary care management and routinely collected outcome scores in the following 2-years. Management options included referral for surgery, conservative (steroid injection and rehabilitation), and no active treatment. Outcome scores collected at 1- and 2-years included the Forgotten Joint Score-12 (FJS-12) questionnaire and 0–10 numerical rating scales for worst and average pain. Treatment allocation is presented as absolute and proportional figures. Change in outcomes across the cohort was evaluated with repeated measures ANOVA, with Bonferroni correction for multiple testing, and post-hoc Tukey pair-wise comparisons. As treatment decision is discrete, no direct contrast is made between outcomes of differing interventions but additional explorative outcome change over time evaluated by group. Significance was accepted at p=0.05 and effect size as per Cohen's values. Results. 81 patients, 50 (61.7%) male, mean age 46.5 years (SD13.13) presented in the study timeframe. 32 (40.3%) received conservative management and 49 (59.7%) were listed for surgery. Six (18.8%) of the 32 underwent subsequent surgery and nine of the 49 (18.4%) patients switched from planned surgery to receiving non-operative care. Two post-operative complications were noted, one cerebrovascular accident and one deep vein thrombosis. The cohort improved over the course of 2-years in all outcome measures with improved mean FJS-12 (34.36 points), mean worst pain (3.74 points) average pain (2.42 points) scores. Overall change (all patients) was statistically significant for all outcomes (p<0.001), with sequential year-on-year change also significant (p<0.001). Effect size of these changes were large with all Cohen-d values over 1. Controlling for age and BMI, males reported superior change in FJS-12 (p=0.04) but worse pain outcomes (p<0.03). Further explorative analysis highlighted positive outcomes across all surgical, conservative and no active treatment groups (p<0.05). The 15 (18%) patients that switched between surgical and non-surgical management also reported positive outcome scores (p<0.05). Conclusion(s). In a regional specialist physiotherapy-led soft tissue knee clinic around 60% of degenerative meniscal tears assessed were referred for surgery. Over 2-years, surgical, non-operative and no treatment management approaches in this cohort all resulted in clinical improvement suggesting that no single strategy is effective in directly treating the meniscal pathology, and that perhaps none do. Clinical intervention rather is directed at individual symptom management based on clinical preferences. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

The World Health Organisation (WHO) has included low back pain in its list of twelve priority diseases. Notably, Degenerative disc disease (DDD) presents a large, unmet medical need which results in a disabling loss of mechanical function. Today, no efficient therapy is available. Chronic cases often receive surgery, which may lead to biomechanical problems and accelerated degeneration of adjacent segments. Our consortium partners have developed and studied mesenchymal stem cell-based, regenerative therapies trials. In previous phase 2 trial, patients exhibited rapid and progressive improvement of functional and pain indexes after 1 year with no significant side effects. To develop the world's first rigorously proven, effective treatment of DDD, EUROSPINE aims to assess, via a multicentre, randomized, controlled, phase 2b clinical trial including 112 patients with DDD, the efficacy of an allogenic intervertebral mesenchymal stem cell (MSC)-based therapy. This innovative therapy aims to rapidly and sustainably (at least 24 months) reduce pain and disability. In addition, the consortium aims to provide new knowledge on immune response & safety associated with allogeneic BM-MSC intradiscal injection. This simple procedure would be cost-effective, minimally invasive, and standardised. At the end of the RESPINE trial, we aim to propose a broadly available and clinically applicable treatment for DDD, marketed by European SMEs

Introduction. Glenoid inclination, defined as the angle formed by the intersection of a line made of the most superior and inferior points of the glenoid and a line formed by the supraspinatus fossa, has been postulated to impact the mechanical advantage of the rotator cuff in shoulder abduction. An increase in glenoid inclination has previously been reported in patients with massive rotator cuff tears and multiple studies have correlated rotator cuff tears to an increase of the critical shoulder angle, an angle comprised of both the glenoid inclination and acromical index. Glenoid inclination is best measured by the B-angle as it has been shown to be both an accurate and reliable. The purpose of this study was to determine the correlation of glenoid inclination and the presence of degenerative rotator cuff tears. Methods. Data was prospectively collected for study patients assigned to one of two groups. The tear group consisted of patients with degenerative, atraumatic rotator cuff tears, confirmed by MRI and the control group consisted of healthy volunteers without shoulder pain. Inclusion criteria for both groups included age 45 or older. Exclusion criteria included history of previous shoulder surgery, previous patient-recalled injury to the shoulder, presence of glenoid weak, and previous humerus or glenoid fracture. Patients were also excluded from the control group if any shoulder pain or history of rotator cuff disease was present. All patients had standard anterior/posterior shoulder radiographs taken and glenoid inclination was digitally measured with Viztek OpalRad PACS software (Konica Minolta, Tokyo, Japan). The beta angle was measured to determine the glenoid inclincation. Statistical analysis was performed using SPSS version 23 (IBM, Aramonk, NY). Patient age and glenoid inclination were examined with the Shapiro-Wilk test of normality and then compared with student t tests. Gender distribution was compared with chi square test. A p-value of 0.05 was used to represent significance. Results. The study included 26 patients in the tear group and 23 patients in the control group. There was no difference in the age of the two groups (57 vs 54, p=0.292) or gender distribution (p=0.774). The average glenoid inclination was 11.18 (SD=2.67) degrees for the tear group and 5.97 (SD=2.55) degrees for the control group. This difference was statistically significant (p<0.001). Discussion. Glenoid inclination is significantly increased in patients with degenerative rotator cuff tears compared to healthy controls. Tendon overload secondary to increased glenoid inclination may be the primary anatomical factor contributing to the development of degenerative rotator cuff tears

Objectives. Degenerative disc disease (DDD) and osteoarthritis (OA) are relatively frequent causes of disability amongst the elderly; they constitute serious socioeconomic costs and significantly impair quality of life. Previous studies to date have found that aggrecan variable number of tandem repeats (VNTR) contributes both to DDD and OA. However, current data are not consistent across studies. The purpose of this study was to evaluate systematically the relationship between aggrecan VNTR, and DDD and/or OA. Methods. This study used a highly sensitive search strategy to identify all published studies related to the relationship between aggrecan VNTR and both DDD and OA in multiple databases from January 1996 to December 2016. All identified studies were systematically evaluated using specific inclusion and exclusion criteria. Cochrane methodology was also applied to the results of this study. Results. The final selection of seven studies was comprehensively evaluated and includes results for 2928 alleles. The most frequent allele among all the studies was allele 27. After comparing the distributions of each allele with others, statistically significant differences have been found in the distribution of the alleles by the two groups, with an over-representation of allele (A)21 (disease: 3.22%, control: 0.44%). Thus, carrying A21 increased the risk of DDD. Such an association was not found to be statistically significant when considering the risk of OA. Conclusions. The findings suggest that VNTR A21 seems to be associated with higher risk to DDD, however, such an association may not be statistically significant regarding the risk of OA. Cite this article: L. Cong, G. Tu, D. Liang. A systematic review of the relationship between the distributions of aggrecan gene VNTR polymorphism and degenerative disc disease/osteoarthritis. Bone Joint Res 2018;7:308–317. DOI: 10.1302/2046-3758.74.BJR-2017-0207.R1

Introduction. Facet joint osteoarthritis (FJOA) is a prominent clinical hallmark of degenerative spine disorders. During disease progression, cartilage and subchondral bone tissues undergo increased turnover and remodeling. The structural changes to the subchondral tissue of FJOA have not been studied thus far. In this study, we performed a micro computed tomography (µCT) study of the subchondral cortical plate (SCP) and trabecular bone (STB) in FJOA and determined osteoarthritis-specific alterations. Methods. Twenty-four patients (11 male, 13 female, median age 65) scheduled for decompression and stabilization surgery for degenerative spinal stenosis were included in this study. FJOA specimens were harvested during surgery and analyzed by µCT. Bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp) and trabecular number (Tb.N) were evaluated using CT Analyser. Lumbar facet joints without chondropathy from cadaveric specimens (9 male, 6 female, median age 57) served as healthy controls. Age-, gender- and disease-specific effects were identified by ANOVA (p<0.05) and significant differences confirmed by Bonferroni's post-test. Association between age and structural parameters was determined using correlation analysis. Results. Cortical and trabecular bone structural parameters of FJOA were similar between males and females. Compared to healthy controls, FJOA specimens demonstrated significantly greater trabecular Tb.N (1.97±0.11 vs 1.24±0.04 mm-1) and decrease of Tb.Sp (0.44±0.03 vs 0.69±0.03 mm). Conversely, subchondral cortical plate thickness (0.62±0.08 vs 1.60±0.08 mm) and porosity (22.9±1.9 vs 31.5±2.1%) were significantly less compared to healthy specimens. Tb.Th was equal between patients and controls. Age was positively correlated with Tb.N (r=0.48, p=0.02) and negatively correlated with Tb.Sp (r=−0.44, p=0.03) and cortical plate thickness (r=−0.52, p=0.04) in FJOA. Cortical and trabecular bone parameters did not associate in healthy and osteoarthritic facet joints. Conclusion. FJOA bone remodeling is characterized by thinning of the SCP and an increase in the number of subchondral trabeculae. Remodeling of cortical and trabecular bone might occur in an uncoupled fashion. Targeting elevated subchondral bone remodeling might slow progression of lumbar FJOA

Introduction. Augmentation of spinal fusion using bone grafts is largely mediated by the osteoinductive potential of mesenchymal stem cells (MSC) that reside in cancellous bone. Iliac crest (IC) is a common autograft, but its use presents an increased risk for donor-site pain, morbidity and infection. Degenerative facet joints (FJ) harvested during facetectomy might servce as alternative local grafts. In this study, we conducted an intra-individual comparison of the osteogenic potential of MSC from both sources. Methods. IC and degenerative FJ were harvested from 8 consecutive patients undergoing transforaminal lumbar interbody fusion surgery for spinal stenosis. MSC were isolated by collagenase digestion, selected by plastic adherence and minimally expanded for downstream assays. Clonogenic and osteogenic potential was evaluated by colony formation assays in control and osteogenic culture medium. Osteogenic properties, including alkaline phosphatase (ALP) induction, matrix mineralization and type I collagen mRNA and protein expression were characterized using quantitative histochemical staining and reverse transcription PCR. Spontaneous adipogenesis was analysed by adipocyte enumeration and gene expression analysis of adipogenic markers. Results. Average colony-forming efficiency in osteogenic medium was equal between IC (38±12%) and FJ (36±11%). Osteogenic potential at the clonal level was 55±26 and 68±17% for IC and FJ MSC, respectively. Clonogenic and osteogenic potential were significantly negatively associated with donor age. Osteogenic differentiation led to significant induction of ALP activity in IC (6-fold) and FJ (8-fold) MSC. Matrix mineralization quantified by Alizarin red staining was increased by osteogenic differentiation, yet similar between both MSC sources. Protein expression of type I collagen was enhanced during osteogenesis and significantly greater in IC MSC. Correspondingly, COL1A2 mRNA expression was higher in osteogenically differentiated MSC from IC. Adipocyte numbers showed significant differences between IC (63±60) and FJ (18±15) MSC under osteogenic conditions. Negative (GREM1) and positive (FABP4) adipogenic markers were not differentially expressed between sources. Conclusion. MSC from IC and degenerative FJ largely display similar clonogenic and osteogenic properties in vitro. Differences at the molecular level are not likely to impair the osteoinductive capacity of FJ MSC. Facetectomy samples are viable bone autografts for intervertebral spinal fusion

Summary. Carriers for local delivery of stem cells into degenerative intervertebral discs need to be tested under physiological loading since stem cell viability, density and differentiation, as well as carrier stability are strongly affected by loading. Introduction. The success of the local delivery of mesenchymal stem cells (MSCs) to degenerative discs relies on three main factors: (i) an appropriate delivery method, (ii) a suitable carrier, (iii) resistance to loading forces. Bioreactors allow the application of loading to whole intervertebral discs and represent a useful tool to screen the potential of new regenerative therapies. We have previously shown that hydrogel delivery through the endplate (EP) leaves the annulus fibrosus (AF) intact (as opposed to an approach through the AF). Furthermore, we have found that the physiological loading needs to be adapted for nucleotomised discs. In this study we compare the behaviour of two MSCs carriers under loading in a whole IVD bioreactor. Materials & Methods. MSCs were isolated from human bone marrow after approval by the local ethical commission and written consent of the patient (age: 20–60 years). Whole IVDs were harvested from calf tails obtained from the local abattoir. Partial nucleotomies were achieved by mechanically removing the nucleus pulposus (NP) through the endplate. Firstly, hMSCs suspended in hyaluronan thermoreversible hydrogel. 2. (6×10. 6. cells/ml) were supplied to the nucleotomised IVDs and the removed EP was re-inserted. Discs were either loaded for one week at 0.06 ± 0.02 MPa, 0.1 Hz, 4 hours/day (n=4) or kept unloaded in culture medium (control). Secondly, hMSCs suspended in fibrin (100 mg/ml fibrinogen and 500 IU/ml thrombin) were applied to IVDs as above described. Discs were kept unloaded in culture medium for one week and then loaded for two weeks at 0.06 ± 0.02 MPa, 0.1Hz, 3 hours/day (n=4) or kept unloaded (control). Analyses included histology, gene expression and cell viability. Results. On the gene level, it was found that loading is required to induce aggrecan (a major component of the NP tissue) up-regulation in MSCs for both carriers. Aggrecan was up-reguled in MSCs already after one week of loading in the thermoreversible hyaluronan, but only after two weeks MSCs in fibrin. Additionally, the highest expression of keratin-19 (NP marker) was found in the loaded thermoreversible hyaluronan group. However, there was a high cell and material loss under loading in this group. Fibrin was more stable in the chosen experimental conditions, as shown in the safranin O-Fast green staining of the IVD. Indeed, the NP cavity was still filled with fibrin gel after 2 weeks of loading. No significant cell loss or decrease in cell viability was found in the fibrin gel after 2 weeks of loading. Discussion/Conclusion. The hyaluronan thermoreversible hydrogel is superior in promoting the differentiation of MSCs toward the disc phenotype, as attested by the aggrecan up-regulation. However, the fibrin gel has a better stability and is more effective at maintaining a high density of MSCs, even under loading. In conclusion, stem cell carriers need to be evaluated in a relevant setting, e.g. in an IVD under load. The study was partially supported by a NASS Research grant

We obtained intervertebral discs with cartilage endplates and underlying cancellous bone at operation from patients with degenerative disc disease and then used immunohistochemical techniques to localise the nerves and nerve endings in the specimens. We used antibodies for the ubiquitous neuronal protein gene product 9.5 (PGP 9.5). Immunoreactivity to neuropeptide Y was used to identify autonomic nerves and calcitonin gene-related peptide (CGRP) and substance P to identify sensory nerves. Blood vessels were identified by immunoreactivity with platelet-endothelial cell-adhesion molecule (CD31; PECAM). In a control group with no known history of chronic back pain, nerve fibres immunoreactive to PGP 9.5 and neuropeptide Y were most closely related to blood vessels, with occasional substance P and CGRP immunoreactivity. In patients with severe back pain and markedly reduced disc height, proliferation of blood vessels and accompanying nerve fibres was observed in the endplate region and underlying vertebral bodies. Many of these nerves were immunoreactive to substance P or CGRP, and in addition, substance P- and CGRP-immunoreactive nociceptors were seen unrelated to blood vessels. Quantification by image analysis showed a marked increase in CGRP-containing sensory nerve fibres compared with normal control subjects. We speculate that a chemotactic response to products of disc breakdown is responsible for the proliferation of vascularity and CGRP-containing sensory nerves found in the endplate region and vertebral body adjacent to degenerate discs. The neuropeptides substance P and CGRP have potent vasodilatory as well as pain-transmitting effects. The increase in sensory nerve endings suggests increase in blood flow, perhaps as an attempt to augment the nutrition of the degenerate disc. The increase in the density of sensory nerves, and the presence of endplate cartilage defects, strongly suggest that the endplates and vertebral bodies are sources of pain; this may explain the severe pain on movement experienced by some patients with degenerative disc disease

Matrix metalloproteinase enzymes (MMPs) play a crucial role in the remodeling of articular cartilage, contributing also to osteoarthritis (OA) progression. The pericellular matrix (PCM) is a specialized space surrounding each chondrocyte, containing collagen type VI and perlecan. It acts as a transducer of biomechanical and biochemical signals for the chondrocyte. This study investigates the impact of MMP-2, -3, and -7 on the integrity and biomechanical characteristics of the PCM.

Human articular cartilage explants (n=10 patients, ethical-nr.:674/2016BO2) were incubated with activated MMP-2, -3, or -7 as well as combinations of these enzymes. The structural degradative effect on the PCM was assessed by immunolabelling of the PCM's main components: collagen type VI and perlecan. Biomechanical properties of the PCM in form of the elastic moduli (EM) were determined by means of atomic force microscopy (AFM), using a spherical cantilever tip (2.5µm).

MMPs disrupted the PCM-integrity, resulting in altered collagen type VI and perlecan structure and dispersed pericellular arrangement. A total of 3600 AFM-measurements revealed that incubation with single MMPs resulted in decreased PCM stiffness (p<0.001) when compared to the untreated group. The overall EM were reduced by ∼36% for all the 3 individual enzymes. The enzyme combinations altered the biomechanical properties at a comparable level (∼36%, p<0.001), except for MMP-2/-7 (p=0.202).

MMP-induced changes in the PCM composition have a significant impact on the biomechanical properties of the PCM, similar to those observed in early OA. Each individual MMP was shown to be highly capable of selectively degrading the PCM microenvironment. The combination of MMP-2 and -7 showed a lower potency in reducing the PCM stiffness, suggesting a possible interplay between the two enzymes. Our study showed that MMP-2, -3, and -7 play a direct role in the functional and structural remodeling of the PCM.

Acknowledgements: This work was supported by the Faculty of Medicine of the University of Tübingen (grant number.: 2650-0-0).

Background/Purpose of study. The increasing aging of the population will see a growing number of patients presenting for spine surgery with appropriate indications but numerous medical comorbidities. This complicates decision-making, requiring that the likely benefit of surgery (outcome) be carefully weighed up against the potential risk (complications). We assessed the influence of comorbidity on the risks and benefits of spine surgery. Methods. 3′699 patients with degenerative lumbar disorders, undergoing surgery with the goal of pain relief, completed the multidimensional Core Outcome Measures Index (COMI; scored 0–10) before and 12 months after surgery. At 12mo they also rated the global treatment outcome and their satisfaction. Using the Eurospine Spine Tango Registry, surgeons documented surgical details, American Society of Anesthesiologists (ASA) scores and surgical/general complications. Results. 29.8% patients were rated ASA1 (normal healthy), 44.8% ASA2 (mild/moderate systemic disease), 25.0% ASA3 (severe) and 0.4% ASA4 (life-threatening). In going from ASA1 to ASA3 (ASA4 group too small), surgical complications increased significantly from 3.6% to 11.1% and general complications increased from 2.3% to 12.6%; 12-month outcomes showed a corresponding decline, with a good global outcome being reported by 78% ASA1 patients, 76% ASA2, and 68% ASA3. Satisfaction with treatment was 87%, 85%, and 79%, respectively and reduction in COMI, 4.2±2.9, 3.7±3.0, and 3.3±3.0 points, respectively. Conclusion. The negative impact of comorbidity on the outcome of spine surgery has not been well investigated/quantified to date. The ASA grade may be helpful in producing algorithms for decision-making and preoperative counselling regarding the corresponding risks and benefits of surgery. No Conflict of interest. No funding obtained. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Summary Statement

This project proves that Patellofemoral (PF) joint degeneration is not a contraindication to medial unicompartmental knee replacement.

Pedicle screw fixation is an effective and reliable method for achieving stabilization in lumbar degenerative disease. The procedure carries a risk of violating the spinal and neural canal which can lead to nerve injury. This audit examines the accuracy of screw placement using intra-operative image guidance.

Retrospective audit of patients undergoing lumbar pedicle screw fixation using image guidance systems over an 18-month period. Case records were reviewed to identify complications related to screw placement and post-operative CT scans reviewed to study the accuracy of screw position.

Of the 98 pedicle screws placed in 25 patients, pedicle violation occurred in 4 screw placements (4.1%). Medial or inferior breach of the pedicle cortex was seen in 2 screws (2%). Nerve root injury as a consequence of this violation was seen in one patient resulting in irreversible partial nerve root dysfunction. Mean set up time for the guidance system was 42 minutes. The mean operative time was 192 minutes.

Violation of either the medial or inferior pedicle cortex during placement of fixation screws is a rare, but potentially serious complication bearing lasting consequences. Image-guided placement can be helpful and possibly improve accuracy; particularly in patients with distorted spinal anatomy.

Despite promising results in attempting intervertebral disc regeneration, intradiscal cell transplantation is affected by several drawbacks, including poor viability in the harsh disc environment, low cost-effectiveness, and immunogenic/tumorigenic concerns. Recently, the development of cell-free approaches is gaining increasing interest in the field, with a particular regard towards extracellular vesicles (EVs). Nucleus pulposus cell (NPC) progenitors characterized by Tie2 expression have shown a higher chondrogenic differentiation potential compared to MSCs. The aim of this study was to investigate the putative regenerative effects of EVs isolated from Tie2-overexpressing NPC progenitors on degenerative NPCs. NPCs were isolated from young donors and underwent an optimized culture protocol to maximize Tie2 expression (NPCs. Tie2+. ) or a standard protocol (NPCs. STD. ). Following EV characterization, NPC isolated from patients affected by intervertebral disc degeneration (IDD) were treated with either NPCs. Tie2+. -EVs or NPCs. STD. -EVs. Cell proliferation and viability were assessed with the CCK-8 assay. Cell apoptosis and necrosis were evaluated with the Annexin V/PI assay. Cell senescence was investigated with b-galactosidase staining. EV uptake was assessed with PKH26 staining of EVs under confocal microscopy. Treatment with EVs isolated from young NPC donors significantly increased degenerative NPC viability, especially in samples treated with NPCs. Tie2+. -EVs. Likewise, NPCs. Tie2+. -EVs significantly reduced cell senescence and did not show to exert necrotic nor apoptotic effects on recipient cells. Furthermore, EV uptake was successfully observed in all treated cells. NPCs. Tie2+. -EVs demonstrated to significantly enhance degenerative NPC viability, senescence and apoptosis. The use of committed progenitors naturally residing the in the nucleus pulposus may optimize EV regenerative properties and constitute the basis for a new therapy for IDD

Mechanical loading is important to maintain the homeostasis of the intervertebral disc (IVD) under physiological conditions but can also accelerate cell death and tissue breakdown in a degenerative state. Bioreactor loaded whole organ cultures are instrumental for investigating the effects of the mechanical environment on the IVD integrity and for preclinical testing of new therapies under simulated physiological conditions. Thereby the loading parameters that determine the beneficial or detrimental reactions largely depend on the IVD model and its preparation. Within this symposium we are discussing the use of bovine caudal IVD culture models to reproduce tissue inflammation or matrix degradation with or without bioreactor controlled mechanical loading. Furthermore, the outcome parameters that define the degenerative state of the whole IVD model will be outlined. Besides the disc height, matrix integrity, cell viability and phenotype expression, the tissue secretome can provide indications about potential interactions of the IVD with other cell types such as neurons. Finally, a novel multiaxial bioreactor setup capable of mimicking the six degrees-of-freedom loading environment of IVDs will be introduced that further advances the relevance of preclinical ex-vivo testing