Oral Presentations

Introduction: As robotic-guidance and minimally invasive approaches become more prevalent in spine surgery, there is a growing interest in high-level scientific evidence of their clinical value. MIS ReFRESH is the first prospective, comparative, multi-center study designed to assess differences in surgical complication and revision rates, and exposure to intra-operative radiation, in adult degenerative conditions, operated in a minimally invasive (MIS) approach in 1-to-3 level fusions. Materials and Methods: Multicenter data (9 sites) were prospectively collected from 379 adult patients indicated for fusion surgery, including demographics, complications, need for revision surgery and use of intra-operative fluoroscopy (in seconds). A single site randomized patients between arms, while other sites enrolled exclusively to one arm. We compared of incidence of revision surgeries and clinical complications (surgical and medical) through a logistic regression model (Cox) as well as intra-operative fluoroscopy use. Results: Altogether, 9 sites enrolled 379 cases: 287 in the robot-guided arm (RG), and 92 in the fluoro-guided arm (FG). One site randomized patients, 15 to RG and 11 to FG. Mean age of RG patients was 59.1 years vs. 62.4 for FG (p = 0.032) and BMI was 31.4 vs. 28.0, respectively (p Conclusion: We report our findings from a prospective, multi-center, comparative study of MIS lumbar fusions performed with robotic-guidance in 287 patients vs. fluoro-guidance in 92 controls. RR for a complication or a revision surgery was significantly higher in FG during the first year of follow-up compared to RG (5.3-fold and 7.1-fold, respectively). RG reduced fluoroscopy exposure time per case by 78%, or almost a minute, helping offset the patients’ exposure during the pre-operative CT scan required for planning the robotic procedure. Introduction: Human induced pluripotent stem cell-derived neural stem cells (hiPS-NSCs) represent an exciting therapeutic strategy for traumatic spinal cord injury (SCI) as they can replace lost neural circuits, remyelinate denuded axons and provide local neurotrophic support. Unfortunately, over 95% of affected individuals are in the chronic phase of their injuries where dense deposits of chondroitin sulfate proteoglycan (CSPG) in the glial/CSPG scar impair neurite outgrowth and regenerative cell migration. Several scar-modifying enzymes have been shown to synergistically enhance NSC-mediated recovery, however, nonspecific intrathecal administration can produce off-target effects. We aimed to generate a genetically-engineered line of hiPS-NSCs, termed Spinal Microenvironment Modifying and Regenerative Therapeutic (SMaRT) cells, which are uniquely capable of expressing a scar-modifying enzyme within their local environment to enhance functional recovery. Material and Methods: A proprietary CSPG-degrading enzyme was genetically integrated into hiPS-NSCs using non-viral transposon technology. An constitutive EF1α promoter was placed upstream of the enzyme linked by a 2A cleavage peptide to a nuclear import tagged red fluorescent protein (RFP) reporter. A monoclonal line of resultant SMaRT human cells was generated by single-cell fluorescence activated cell sorting (FACS) and expanded. Enzyme expression and enzyme activity was extensively characterized in vitro by biochemical assays and antibody-based slot blots with a chondroitin sulfate (CS) or human CSPG substrate. Ex vivo injured rodent cervical cord sections were also incubated with conditioned media from wild-type hiPS-NSCs and SMaRT cells, followed by immunolabelling to assess in situ CSPG degradation. To assess in vivo efficacy, T-cell deficient RNU rats (N = 60) with translationally-relevant chronic C6-7 clip-contusion injuries were randomized to receive: (1) injury + vehicle, (2) injury + conventional hiPS-NSCs, (3) injury + SMaRT cells, or (4) sham surgery (laminectomy alone). Weekly neurobehavioural assessments of all animals include BBB open-field locomotor scoring, inclined plane test, forelimb grip strength and tail flick sensory test. CatWalk digital gait assessment is also being completed every 4 weeks. Results: The monoclonal SmaRT cell line uniformly expresses the RFP reporter and demonstrates key retained hiPS-NSC characteristics such as repeated neurosphere formation, a 46XY karyogram, nestin cytoplasmic staining and the capacity to differentiate along all three neuroglial lineages (neurons, oligodendrocytes and astrocytes). The enzyme expressed by SMaRT cells rapidly degrades CSPGs on WST-1 and DMMB biochemical assays and allows neurons to extend into scar mimicking CSPG-rich regions in vitro. Furthermore, unlike wild-type hiPS-NSC media, conditioned SMaRT cell media can degrade rodent CSPGs in ex vivo injured cord cryosections as assessed by CS-56 (intact long-chain CSPG) immunohistochemistry. While blinded in vivo sensorimotor behavioural assessments are ongoing with a long-term 40-week endpoint, interim histological analyses shows that grafted human cells are extending remarkably long (≥ 20 000 µm) axons along host white matter tracts in both the rostral and caudal directions. These processes extend from the cervicomedullary junction to below the mid-thoracic cord. Conclusion: This work provides exciting proof-of-concept data that genetically-engineered SMaRT cells can degrade CSPGs in vitro and that human NSC transplants can grow long axons in chronic cervical SCI to potentially form a bridge for sensorimotor signal transmission. Introduction: Incidental dural tears (IDTs) occur in 3-16% of open spine surgeries spinal surgery and 1.7-4.3% of percutaneous endoscopic spine surgeries 1-3). Preventive strategies are important and essential during the endoscopic procedure, since conversion to open surgery for repair must necessitate a wider dissection and laminectomy and, consequently, persistent back pain may occur. Analyzing association of IDTs with specific operative maneuvers during biportal endoscopic spine surgery (BESS) would help surgeons to formulate strategies for decreasing their incidence. Material and Methods: We retrospectively reviewed all BESSs performed for degenerative lumbar spine diseases, including lumbar disc herniation (LDH), recurrent LDH, spinal stenosis with/without degenerative spondylolisthesis, and spondylolytic spondylolisthesis, from December. 2014 to December. 2016. Retrospective review of the causes of IDTs and the associated operative maneuvers during BESS by three surgeons were analyzed to modify the pattern of the procedures and the operative plan to prevent un-hopeful IDTs. Follow-up magnetic resonance imaging examination was performed at postoperative 2 or 3 days, 1 week, and 1 month postoperatively to determinate the success of the treatment. Results: There were 16 cases (1.2%) of IDTs in a total of 1351 operations. Of these, 10 (62.5%) occurred within the first 6-months during the learning curve. The IDT locations included 7 cases at central and 9 cases at lateral side to the dura. The Small-sized tears (≤ 10 mm) occurred in 13 cases; (11 slit tears and 2 flap tears) while, the Large-sized tears ( > 10 mm) occurred in 3 cases; (2 slit tears and 1 flap tear). Specific maneuvers associated with IDTs included punching under blurred vision (6 cases, 37.5%), curetting for adhesiolysis (4), direct injury to the central folding of the dura (2), burring over the dura after flavectomy (1), imprecise handling of the muscle dilator (1), laminectomized sharp bone-edges (1), and blind procedures under the ligamentum flavum (1). The initial treatments included mechanical packing with Gelfoam (7), Fibrin glue (6), immediate open repair (2), and blood patching for unnoticed IDT (1). The Success rate of the compression technique without direct suturing for small-sized IDTs less than 10 mm was 92.3% (12/13). Conversion to open repair was needed in 3 cases of large tears and one 1 case of small tear after failure of blood patching. There were no progression instances to wound infection or pyogenic spondylitis. Conclusion: Maintaining a clear surgical field during BESS is very important to prevent IDTs while securing saline outflow and maintaining thorough control of small bleeds. Small IDTs (≤10 mm) may be treated successfully with the compression technique even without direct suturing. Large-sized IDTs and large flap tears were recommended to open repair. Practiced handling of the surgical instruments safely and a thorough understanding of the surgical anatomy under a saline-filled surgical field may reduce the risk of IDTs during BESS, especially during the initial learning curve. Introduction: The intervertebral disc is integral to the stability, flexibility and function of the spine. However, despite technological advances the common understanding of the anatomy of the intervertebral disc is that of a bi-layered structure consisting of the annulus fibrosus (AF) and nucleus pulposus (NP). Some groups have demonstrated a histological tri-layered structure with division of the AF into outer annular (OA) and inner annular (IA) segments. We performed a qualitative laboratory based animal study using 9.4 T MRI, light microscopy histology, immunohistochemistry and polarised microscopy revealing new insights into the microarchitecture of the intervertebral disc. We demonstrated five distinct regions with each layer possessing unique anatomical properties that underpin its physiological and biomechanical function in health and disease. Materials and Methods: 30 lumbar intervertebral discs from 6 mature ewes involved in a cellular regenerative study were acquired at necropsy. Lumbar discs L2/3, L3/4 and L4/5 in all ewes had been exposed to a validated injury model consisting of a 6 x 20 mm incision into the AF via an anterolateral retroperitoneal approach, whilst discs L1/2 and L5/6 served as uninjured controls. Disc degeneration had been allowed to progress naturally up to 3 months. 9.4 T MRI was applied to all discs followed by careful preparation for microanatomical analysis. 5 micron thick slides were acquired consisting of vertebral body-disc-vertebral body using a standard rotatory microtome and prepared for histological analyses, immunohistochemistry and polarised microscopy. Results: The 9.4 T MRI provided high resolution images of the intervertebral disc demonstrating exceptional anatomical detail that surpassed any previously demonstrated by radiological techniques. Radiological confirmation of sinuvertebral nerve and perforating artery penetration of the degenerate intervertebral discs was confirmed radiologically for the first time providing new insights into the physiological processes that take place during disc degeneration. Furthermore, we were able to radiologically demonstrate a collagenous structure to the NP. Early changes in the transitional zone (TZ) of control discs provides insight into possible early degenerative changes in this region in adjacent level degenerative disc disease. The 9.4 T MRI findings were complemented by histology and polarised birefringence microscopy demonstrating 5 discrete microanatomical regions of the intervertebral discs consisting of the OA, IA, TZ, and peripheral and central NP (pNP and cNP respectively). The lamellation of the TZ could be clearly distinguished from the IA and OA. The pNP consists of a proteoglycan rich matrix with distinct concentric collagenous sheets forming a lattice of linearly arranged chondrocytes and admixed notochordal cells. This structure is completely lost in the cNP, a region focally exposed to multidimensional forces. Conclusion: 9.4 T MRI in conjunction with modern histological techniques and polarised microscopy provide novel insights into the architecture of the intervertebral disc, defining 5 distinct regions that underpin it’s biomechanical and physiological properties. Introductions: Osteoporotic vertebral compression fractures (OVCFs) are common in the elderly. Traditional bilateral PKP approaches were regarded as safe and effective. Nevertheless, unilateral PKP approaches were accepted attribute to surgical time, safety, and less expense. We performed the meta-analysis to compare the unilateral and bilateral PKP for patients with OVCF in terms of the short- and long-term clinical outcomes and complications. Methods: Randomized or non-randomized controlled trials published up to Jul. 2017 that compared the unilateral and bilateral PKP for the treatment of OVCF were included by a comprehensive search in the Cochrane, PubMed, MEDLINE, EMBASE, Web of Science, and CNKI. The main measure outcomes included: the short- and long-term postoperative Visual Analogue Scale (VAS) scores, the short-term postoperative Oswestry Disability Index (ODI), operation time, restoration rate, cement dosage and leakage, and postoperative adjacent-level fractures. Results: A total of 17 studies involving 1344 patients were included in the meta-analysis. The mean operative time and cement dosage were less in the unilateral groups compared with the bilateral groups (p Conclusion: In conclusion, our meta-analysis showed unilateral PKP was associated with shorter operative time, lower VAS in the short-term and less dosage of PMMA than bilateral PKP. However, Bilateral PKP approach has high restoration rate. There was no significative difference in the long-term clinical outcomes and complications between them. More high-quality randomized controlled trails should be required to make sure which method is better for the treatment of OVCF in the future. Introduction: Degenerative disc disease (DDD) is a common cause of lower back pain. Calcification of the intervertebral disc (IVD) has been correlated with DDD, and is especially prevalent in scoliotic discs. The appearance of calcium deposits has been shown to increase with age, and its occurrence has been associated with several other disorders such as hyperparathyroidism, chondrocalcinosis, and arthritis. Trauma, vertebral fusion and infection have also been shown to increase the incidence of IVD calcification. Calcification is the product of free calcium (Ca2+) and phosphate (PO4). Our preliminary data suggest that ionic calcium and P04 content are increased from [2.0 – 8.0 mM] and [1.0 – 4.0 mM], for mild, moderate and severe degenerative IVDs, respectively. The roles of these individual ions on IVD function and in the development DDD is unknown. In this study, we evaluated the effects of Ca2+, PO4, and their combination on IVD nucleus pulposus (NP) and annulus fibrosis (AF) cells. Material and Methods: Bovine IVD cells were isolated from bovine caudal tails of 20-24-month-old steers. Cells were recovered from NP and AF tissue by sequential digestion with Pronase followed by Collagenase, and expanded in low glucose DMEM medium supplemented with 10% heat-inactivated FBS. Cells were expanded in flasks then prepared for 3D culturing in alginate beads at a density of 1*106 cells/mL. Beads were cultured in medium containing increasing Ca2+ [1.0, 3.0, 6.0 mM], PO4 [1.0, 2.0, 4.0 mM], or their combination and cultured for 12 days. A modified GAG assay was performed on the beads to determine proteoglycan content and Western blotting for type II collagen (Col II) synthesis. Cell viability was determined by counting live and dead cells in the beads following incubation with the Live/Dead Viability Assay kit. Cell numbers in beads at the end of the incubation period was determined using Quant-iT dsDNA Assay Kit. Bovine IVD organ culture model was performed as previously described. IVDs were cultured for 4 weeks in Ca2+ [1.0 and 6.0 mM] with and without PO4 [4.0 mM]. Results: Using similar Ca2+ concentrations found in degenerate [1.8 – 6.0 mM], Ca2+ dose-dependently decreased matrix protein synthesis of proteoglycan and Col II in NP and AF cells (n = 4). Moreover, increasing PO4, from 1 – 4 mM, further decreases in matrix protein synthesis was observed (n = 4). Interestingly, although cell viability was unaltered from higher PO4 or Ca2+ concentrations, the combination of PO4 and Ca2+ significantly affected cell proliferation (n = 3). IVDs cultured in increasing Ca2+ demonstrated decreased total proteoglycan content in both NP and AF regions. Western blotting for aggrecan in NP and AF tissues showed similar results. Histology and immunohistochemistry was performed to identify proteoglycan and nerve growth factor expression, respectively. Conclusion: Our results suggest that changes in the local concentrations of calcium and PO4 are not benign, and that the combination of these ions affects IVD cell growth and matrix protein synthesis. Ca2+ and PO4 may be a contributing factor in IVD degeneration and pain. Introduction: Hemivertebra (HV) resection with short segmental fusion for congenital scoliosis is a standard procedure for young children with localized deformity. However, such a technique might not best address the deformities with long-spanned kyphotic scoliosis secondary to HV. In these cases, a hybrid growing rod technique with hemivertebrectomy and short fusion may be the option. Therefore, the current study aimed to evaluate the clinical outcomes and complications of this hybrid technique. Materials and Methods: Thirteen patients who were treated with this hybrid technique were reviewed. There were 5 patients with single rod and 8 with dual rods after apical hemivertebra resection and short fusion. They had averagely 2.2 lengthening procedures with an average follow-up of 34.7 months. The magnitude of coronal/sagittal deformity and T1-S1 height were measured on the preoperative, postoperative, and last follow-up radiographs. The complications were recorded. Results: The average coronal Cobb angle of main curve was 74.8 degrees before the index surgery, 24.3 degrees after the index surgery, and 25.6 degrees at the last follow-up. The correction rate was 65.8%. The mean global kyphosis was corrected from 64.2 degrees to 34.3 degrees postoperatively and further improved to 28.3 degrees at the latest follow-up. The average height of T1-S1 was 238.4 mm before the index surgery, 270.5 mm after the index surgery, and 282 mm at the latest follow-up. The average growth rate was 12.8 mm per year. One case had rod breakage 8 months after the index surgery and was revised during the planned lengthening. One case exprenced superficial wound infection in 3 weeks after the index surgery and were successfully with debridement. Conclusion: The hybrid growing rod technique with hemivertebrectomy and short fusion is safe and effective in the treatment of congenital kyphotic scoliosis with a long curve. The technique is an alternative for young children with multiple anomalous vertebrae and a long curve to avoid early long fusion. Introduction: The goals of surgical correction of adolescent idiopathic scoliosis (AIS) are to achieve a balance spine with a parallel fusion block. Preoperative curve flexibility assessment is integral in the radiographic evaluation and surgical decision making. The aim of this prospective study was to compare five radiographic techniques in flexibility assessment and correlate them to surgical correction. Material and Methods: A prospective comparative observational study was carried out in two academic institutions in Hong Kong and Turkey. Consecutive patients undergoing AIS surgical collections were recruited between June 2016 to August 2017. Preoperative radiographic evaluation included standing posteroanterior and lateral whole spine, supine, supine side bending, fulcrum bending (FB) in both sites; awake traction in Hong Kong; and supine traction under general anaesthesia (STUGA) in Turkey. Surgical correction and fusion levels were determined by the surgeons’ usual technique, and postoperative radiographs were taken. For each radiographic assessment, correction rate and flexibility percentages were calculated, and correction index was the correction rate as a percentage of the flexibility. Statistical differences were calculated. Results: 76 patients were recruited into the study, but 2 patients had anterior surgery and were excluded from analysis. 74 patients (65 females and 9 males) with an average age of 13.91 years (range, 11-18) at the time of operation. 51 patients had a thoracic major curve (34 cases Lenke 1; 10 Lenke 2; and 7 Lenke 3), and 23 patients had a thoracolumbar or lumbar major curve (21 cases Lenke 5 and 2 Lenke 6). For thoracic curves, mean preoperative standing frontal Cobb was 57.8o (range, 34.3o-79.7o), and the mean postoperative Cobb was 15.5o (range, 1-40.7o) with a mean correction rate of 72.5% (range, 27.1%-97.9%). For lumbar curves mean preoperative Cobb was 50.3o (range, 35o-88o), and the mean postoperative Cobb was 8.0o (range, 0.1o-22o) with a mean correction rate of 84.5% (range, 59.1%-99.8%). The correction indices showed that the most predictive dynamic assessment for AIS correction was FB, compared with STUGA (p = 0.2), awake traction (p = 0.004), supine side bending (p = 0.003), and supine (p = 0.000) for thoracic curves. For lumbar curves, FB, STUGA and supine side bending were similar in prediction (p > 0.05), which were better than supine film (p = 0.000). Conclusion: Although correction rate can give an indication of the amount of correction achieved per case, it is inaccurate to compare between different cases as it does not take into account the intrinsic flexibility of the curve, and does not necessarily reflect on either the surgical technique or the instrumentation strategy. Correction index takes into account of the curve’s intrinsic flexibility, and the closer one gets to 100%, the more effective is the final surgical correction in taking up this flexibility. Our study showed that FB is most predictive in thoracic curves undergoing posterior instrumented fusion. In lumbar curves which are usually more flexible, no statistical significant difference was found amongst different dynamic radiographs in predicting surgical correction. An accurate flexibility assessment will allow improve pre-operative planning for the need of additional release and fusion level determination. Introduction: Surgical site infections (SSI) represent a major complication of spinal surgery, with the patient's physiological skin flora being the main reservoir. The local microbioma of the back is highly specific and differs significantly from other areas of the human body. As the predominant bacteria strains are not covered by the European Standard Specifications for antiseptic evaluation, little is known regarding the specific efficacy of routinely used antiseptics for spinal surgery procedures. Aim of the presented study is to evaluate the efficacy of different antiseptic solutions in a spinal surgery specific in vitro and in vivo setting. Materials & Methods: The bacterial spectrum causing SSI after spinal surgery in our department was analysed retrospectively for 2015. Representative bacterial cultures were harvested from wound swabs and cultivated in Lysogeny Broth. PVP-Iodine (Braunol®), Hexetidin (Isozid®), Propanol/Biphenyol (Kodan forte®) and Octenidin (Octenisept®) were evaluated. Bacterial proliferation was monitored by measuring medium turbidity at 600 nm prior to disinfection, immediately and after 1 and 3 hours to simulate the time course of a surgical procedure. Colony forming units were evaluated on agar plates. Additionally, swabs were taken in the OR from skin incision and the surgical blade after routine disinfection with Propanol/Biphenyol (n = 138) and after changing pre-operative skin preparation to Octenidin (n = 638) as a result of in vitro evaluation. Results: Bacterial spectrum: Staph. epidermidis was responsible for 37% of the SSIs, followed by Propionibacterium acnes (17%), Enterococcus faecalis (14%), and Proteus mirabilis respectively Staph. aureus accounting for 6% each. Staph. epidermidis, Enterococcus faecalis, Proteus mirabilis and Stap aureus could be cultivated from wound swabs and used for the subsequent evaluation. In vitroevaluation: The efficacy of the antiseptic solutions tested varied significantly: Octenidin demonstrated a significantly higher efficacy (p Conclusion: Antisepsis does not automatically mean a total eradication of the local microbiome. Even under standardized in vitro conditions, a significant bacterial load could be detected after disinfection. The antiseptic solutions evaluated differed significantly regarding their efficacy. Octenidin demonstrated a significantly higher effectiveness on a spinal surgery specific microbioma in vitro and in vivo. While the test strains were reduced beyond the level of detection during in vitro evaluation, deeper layers of the skin, which are not reached by antiseptic treatment, may act as reservoir in vivo. Introduction: Sacral Slanting in congenital scoliosis has never been reported despite of its high incidence. Great challenge remains in restoring coronal balance after hemivertebra resection with short fusion in cases with Sacral Slanting. The purpose of this study was to clarify its definition, etiology and surgical strategy. Material and Methods: From July 2004 to December 2014, clinical charts and radiographic data of patients with early-onset congenital scoliosis were reviewed. Posterior hemivertebra resection with short fusion was performed in all cases that met our critieria. Coronal and sagittal parameters, as well as Sacral slanted angle and UIV-Pelvis Angle, were measured. Sacral Slanting was defined as the angle of more than 5° and severe Sacral Slanting was thought to be more than 10°. Statistical analyses were performed. Results: 42 consecutive patients were included. The mean age was 4.0 years old with an average follow-up of 51.7 months. The mean segmental curve was 34.9° before surgery, 4.7° immediately postoperatively, and 8.7° at final follow-up. Trunk shift was 15.4 mm preoperatively, 16.9 mm immediately after surgery and 12.1 mm at final follow-up. Sacral slanted angle was measured as 7.2° before surgery. Sacral Slanting could be noticed in 26 patients with an incidence of 61.9%. Patients with hemivertebrae at or below L3 had higher incidence of Sacral Slanting than that with hemivertebrae above L3. Severe Sacral Slanting was noted in 11 patients with an incidence of 26.2%. Sacral slanted angle was corrected to 5.1° immediately after surgery. And at final follow-up, it was 4.5°. Postoperative UIV-Pelvis Angle was 3.9°. Postoperative UIVT was correlated positively with postoperative TS. Two independent risk factors were identified for postoperative proximal adding-on: larger postoperative Sacral Slanted Angle and larger postoperative UIV-Pelvis Angle. Conclusion: Sacral Slanting was rarely recognized despite its high incidence. The etiology may be congenital malformation and sacrum rotation. Segmental undercorrection and placing a more central and even UIV were wise strategies for congenital EOS with severe Sacral Slanting. Introduction: Pedicle screws have been used for posterior spinal fixation since the free hand technique was first reported in 1959. Multiple methods have since been developed to facilitate more accurate screw placement, such as stereotactic-guiding and intraoperative fluoroscopy, though they also increase radiation exposure and operative interval. Pedicle screws remain technically demanding to place. Aberrant screws can lead to serious neurovascular complications, including radicular pain, sensory loss, damage to great vessels, and damage to the pleural cavity. We propose that a predominant factor of pedicle screw breach is due to the inherent vertebral anatomy involved at a given spinal level. While it has been suggested that vertebrae morphology can influence breach incidence, there has never been a clear link made between isthmus size and the rate of pedicle screw breach. The study aims to investigate the inverse correlation between breach incidence and vertebral isthmus width. Material and Methods: We retrospectively reviewed the post-operative computed tomography (CT) scans of 91 patients who underwent thoracolumbar (T2-L5) surgery at the Jewish General Hospital. Average patient age was 62.9 years and the patients were 58% male and 42% female. Radiologically detectable breach incidence was computed and a Fisher exact test was performed. Each breach was also categorized as minor ( 2 mm). Clinical correlation was not a requirement for presence of breach. Isthmus width is defined as the narrowest portion of the pedicle in the mediolateral plan. The average isthmus width by spinal level, reported by Zindrick in 1986, was then compared to the collected breach incidences by spinal level. A regression analysis and Pearson’s correlation was performed. Results: A total of 656 pedicle screws were analyzed and 233 radiologically detectable breaches were found, though only 8 patients developed post-operative symptoms clinically relevant to the detected breach. The average incidence of breach was 35.5%, while the average incidence of major breach was 8.6%. Breach incidence was over two times higher in the thoracic than the lumbar spine while major breach incidence was three times higher (Fisher exact test, P Conclusion: A thinner vertebral isthmus width significantly increases the pedicle screw breach incidence. The smaller size and complex pedicle morphology of the thoracic spine was breached over two times more frequently than the larger pedicles of the lumbar spine, which allow for more degrees of freedom. Despite the high incidence of cortical bone violation observed, there was little correlation with clinical symptoms and we were unable to conclude the absolute size of breach necessary for symptoms to develop. A breach is not automatically a clinical problem, provided the screw remains structurally sound and the patient symptomless. One must consider every case uniquely. Image-guided assistance may be most useful where breach incidence is highest and isthmus width is lowest, particularly between T3 and T6. Introduction: The thoracic spine is considered as a semi-rigid region in human spine. Several studies have reported dynamic changes of the thoracic spine in terms of motion and cross-sectional area of the thoracic spinal cord. The movement of thoracic spinal cord within dural sac and the change in mid-sagittal diameter in correlation with positional changed is still unknown. The aims of this study were (1) to evaluate the dynamic change of anterior and posterior Space Available for Cord (SAC) of the thoracic spinal cord in the dural sac in three position, neutral, flexion, and extension, and (2) to evaluate the dynamic change of the thoracic spinal cord in mid-sagittal diameter in three positions. Materials and Methods: 118 patients (66 males and 52 females, mean age of 45.6 ± 10.6) who underwent thoracic spine kMRI were evaluated from T4/5 to T11/12 in flexion, neutral, and extension positions. The anterior SAC, posterior SAC, and mid-sagittal thoracic cord diameter were measure at the level of each intervertebral disc from T4-5 to T11-12. The anterior SAC is the distance from posterior borders of the disc to the anterior border of the thoracic cord. The posterior SAC is the distance from the posterior border of the thoracic cord to the anterior border of the posterior column at each level. The mid-sagittal cord diameter is the distance between anterior and posterior border of thoracic cord, and was measured in the mid-sagittal plane of the MRI. The Friedman’s test was used to test the statistical significance for each parameter in three positions, then Wilcoxon-signed-rank test was used for post-hoc analysis. P-value of less than 0.0167 was considered statistically significant after Bonferroni correction. Results: Between three positions, there were statistically significant differences in anterior SAC at levels T8-9 to T11-12 (p Conclusions: Thoracic spinal cord changed in shape and position in the dural sac during positional changes. In flexion position, the thoracic cord at T8-9 and below tended to move anteriorly closer to posterior vertebral body and intervertebral disc. The thoracic cord, itself, increased in mid-sagittal diameter in flexion position at the levels below T8-9. In flexion position there is a higher chance of spinal cord compression if there are lesion in the anterior epidural space, especially at the levels below T8-9. Introduction: Long segment fusion is often utilized in the treatment of symptomatic spinal deformity. Proximal junction kyphosis (PJK) (Kyphotic Cobb angle > 15 degrees) can lead to proximal junctional failure, and has revision surgery rates reported up to 27% within 6 months following primary surgery. As cited in our previous study, the use of a tapered dose of prophylactic bone in UIV (T10), UIV+1 (T9) and UIV+2 (T8) in an instrumented T10-S1 model, which eliminated fractures at T7 (supra adjacent to the augmented T8 vertebra). The tapered dose of bone cement and the disc spaces may buffer axial forces, allowing for a smoother load transfer through the segments. The optimal dose and configuration of the tapered dose of bone cement has also been cited in our previous study. In this current parametric study, we explore the effects of the bone cement placed near the upper and lower end plates and distributed vertically or horizontally in the adjacent proximal vertebrae. Material and Methods: A validated FE model from T6-pelvis was used for the analyses. An osteoporotic model was developed and modified by insertion of pedicle screws and rods from T10 to S1, therein simulating the standard surgical procedure in-silico. Polymethyl methacrylate (PMMA) bone cement was injected in the UIV (T10), UIV+1 (T9) and UIV+2 (T8). 2.5 cc of cement was injected in T10, 2 cc in T9 and 1 cc in T8 near the upper endplate, lower endplate, distributed in a vertical direction and a horizontal direction in the vertebrae. The load was applied to a metal bock 10 mm anterior to the center of the vertebra to simulate flexion moment and the pelvis was fixed. The stresses at the end plates from T7 to T10 were analyzed. Results: Except for 3.8% increase at the T7 inferior endplate for the bone cement placed near the upper endplates, lower stresses were observed when the cement was placed near the upper endplates as compared to placement near the lower endplates, ranging from 3% to 20.5% at the T9 superior endplate. Lower stresses were observed at all endplates for horizontal cement distribution as compared to vertical cement distribution. Conclusion: Our data suggests bone cement should be injected close to the upper endplates and not the lower endplates, to decrease endplate stresses and thus the risk of vertebral fractures. Additionally, as compared to vertically distributed cement, bone cement should be spread horizontally to reduce endplate stresses and thus reducing the risk of compression fractures. Introduction: Surgical decompression and stabilization followed by radiosurgery represents an effective method for local tumor control and neurologic preservation for patients with metastatic epidural spinal cord compression. We have previously demonstrated improvement in HrQOL after this combined modality treatment (“hybrid therapy”). The current analysis focuses on delineation of patient-specific prognostic factors predictive of HrQOL change after combined surgery-SRS treatment of MESCC. Materials and Methods: This is a prospective, single-center, cohort study. One hundred and eleven patients with MESCC who underwent separation surgery followed by SRS were included. Prognostic factors associated with improved patient reported outcome (PRO) measures. PRO tools, i.e. Brief Pain Inventory (BPI) and MD Anderson Symptom Inventory – Spine Tumor (MDASI-SP), both validated in the cancer population, were prospectively collected. Numeric prognostic factors were correlated with PRO measures using the Spearman rank correlation coefficient. Categorical prognostic factors were correlated with PRO measures using the Wilcoxon two-sample test (for two categories) or the Kruskal-Wallis test (for three or more categories). All statistical tests were two-sided with a level of significance Results: One hundred and eleven patients were included in this analysis. Patients with lower pre-operative Medical Research Council (MRC) motor scores experienced a greater decrease in symptom interference (BPI Interference construct (p = 0.03), and individual functional measures including general activity (p = 0.001), walking (p = 0.001) and normal work (p = 0.006)). Lumbar location was associated with better outcomes than cervical or thoracic as noted on the BPI pain experience construct (p = 0.03) and MDASI-SP interference (p = 0.01) and core symptom (p = 0.002) constructs. Patients with ASIA scores of C or D benefit more than those with ASIA E on BPI Interference construct (p = 0.04)). Patients with higher ECOG scores at presentation benefit more than those with low ECOG scores on MDASI-SP interference construct, (p = 0.03)). Women benefit more than men on BPI interference (p = 0.03) and pain experience (p = 0.04) constructs. Patients with prior spinal surgery at the current level of interest benefit less than those which are naïve surgical patients in MDASI-SP interference construct, (p = 0.04). Conclusions: Delineation of patient characteristics associated with HrQOL improvement provides crucial information for patient selection, patient education and setting treatment expectations. For patients with MESCC treated with hybrid therapy using surgery and radiosurgery, the presence of neurological deficits and diminished performance status, lumbar tumor level and female gender were associated with greater PRO improvement. Introduction: This meta-analysis of Randomized Controlled Trials (RCTs) aims to evaluate the efficacy and safety in cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) for treating cervical degenerative disc diseases (CDDDs). Material and Methods: The authors searched RCTs in the electronic databases (Cochrane Central Register of Controlled Trials, PubMed, EMBASE, Medline, Embase, Springer Link, Web of Knowledge, OVID and Google Scholar) from their establishment to march 2016 without language restrictions. We also manually searched the reference lists of articles and reviews for possible relevant studies. Researches on CDA versus ACDF in CDDDs were selected in this meta-analysis. The quality of all studies was assessed and effective data was pooled for this meta-analysis. Outcome measurements were surgical parameters (operative time, blood loss, and length of hospital stay), clinical indexes (neck disability index (NDI), neurological success, range of motion (ROM), Visual Analogue Score (VAS)), complications (the number of adverse events, adjacent segment disease (ASD), and reoperation). Subgroup analysis, sensitivity analysis, and publication bias assessment were also performed, respectively. The meta-analysis was performed with software RevMan 5.3. Results: 37 articles (20 RCTs) with a total 4123 patients (1762 in the CDA and 1472 in the ACDF) met inclusion criteria. Eight types of disc prostheses were used in the included studies. Patients were followed up for at least two years in all the studies. No statistically significant differences were found between CDA and ACDF for blood loss (SMD -0.02; 95% CI (−0.20, 0.17)), length of hospital stay (MD -0.06; 95% CI (−0.19, 0.06)). Statistical differences were found between operative time (MD 14.22; 95% CI (6.73, 21.71)), NDI (SMD −0.27; 95% CI (−0.43, −0.10)), neurological success (RR 1.13; 95%CI (1.08, 1.18)), ROM (MD 6.72; 95%CI (5.72, 7.71)), VAS of neck (SMD -0.40; 95%CI (−0.75, −0.04)), VAS of arm (SMD −0.55; 95%CI (-1.04, -0.06)), the rate of adverse events (RR 0.72 95% CI (0.53, 0.96)), the rate of ASD (RR 0.62; 95% CI (0.43, 0.88)), and reoperation (RR 0.50; 95% CI (0.39, 0.63)). Subgroup analysis stratified by different types of disc prostheses was also performed. Conclusion: CDA is associated with higher clinical indexes and fewer complications than ACDF, indicating that it is a safe and effective treatment for CDDDs. However, the operative time of CDA is longer than ACDF and NDI score of CDA is lower than ACDF. Because of some limitations, these findings should be interpreted with caution. Additional studies are needed. Large, definitive RCTs are needed. Introduction: Despite retrospective studies that have shown that longer packed red blood cell (PRBC) storage duration worsens patient outcomes, randomized clinical trials have found no difference in outcomes. However, no studies have examined the impact of giving the oldest blood (28 days-old or more) on morbidity within spine surgery. Our objective in this study was to describe the association between storage duration of PRBCs and perioperative adverse events in patients undergoing spine surgery at a tertiary care center. Materials and Methods: The surgical administrative database at our institution was queried for patients transfused with PRBCs who underwent spine surgery between December 4, 2008 and June 26, 2015. Patients undergoing spinal fusion, tumor-related surgeries, and other identified spine surgeries were included. Patients were divided into two groups based on storage duration of blood transfused: exclusively ≤ 28 days’ storage or exclusively > 28 days’ storage. The primary outcome was composite in-hospital morbidity, which included: (1) infection, (2) thrombotic event, (3) renal injury, (4) respiratory event, and/or (5) ischemic event. Results: In total, 1,141 patients who received a transfusion were included for analysis in this retrospective study; 710 were transfused exclusively with PRBCs ≤ 28 days’ storage and 431 exclusively with PRBCs > 28 days’ storage. Perioperative complications occurred in 119 patients (10.4%). Patients who received blood stored for > 28 days had higher odds of developing any one complication (odds ratio [OR] = 1.82; 95% confidence interval [CI], 1.20-2.74; P = 0.005) even after adjusting for competing perioperative risk factors. Conclusion: Blood stored for > 28 days is independently associated with higher odds of developing perioperative complications in patients transfused during spinal surgery. Our results suggest that blood storage duration may be an appropriate parameter to consider when developing institutional transfusion guidelines that seek to optimize patient outcomes. Introduction: Currently the UK national screening committee does not recommend screening for adolescent idiopathic scoliosis (AIS). In two tertiary spinal centres serving two different but large geographical areas, we investigated first presentation of AIS and the potential impact that introducing a school prevention programme (SPP) may have. In light of evidence for bracing as well as new technology for the growing spine including vertebral body tethering there is a real need to re-explore school screening. Methods: Royal Devon and Exeter Hospital and St. George’s Hospital performed a retrospective case review of all new children referred over a 2-year period (2015-16) was performed, noting age at presentation, aetiology, curve magnitude, Risser grade, and intention to treat on first consultation. Four groups of patients were identified: early onset idiopathic ( Results: Of 488 cases, 286 were diagnosed with scoliosis (Cobb > 10°), 66% (n = 189) female. 26 with early onset scoliosis, mean Cobb angle of 37.7° and 37 patients in the syndromic group, mean Cobb of 44° respectively. We identified that of 57 patients with AIS and Risser grade 0-2 of which 11.1% (n = 32) were within bracing range, and 8.7% (n = 25) were beyond bracing magnitude. 58% (n = 166) with Risser grade 3-5. 30% (n = 87) curves too large to brace. Discussion: Fusion of the spine for scoliosis is an invasive treatment carrying significant morbidity. Only 11.1% of first presentation AIS fulfilled the SRS criteria for bracing. Following publication of level I evidence demonstrating that bracing is effective at altering the natural history of AIS and the results of this study give a good snapshot of current incidence, strongly supporting the need to introduce a school prevention programme in the U.K. Introduction: Early onset scoliosis (EOS) was first described in 1936 and since then, the concept had been evolving. Nowadays, EOS is used to depict a deviation of more than 10° in the frontal plain measured by Cobb’s method. Previous treatment options included premature spine fixation, leading to cardiopulmonary complications and short torso syndrome. The advent of new treatment choices has resulted in diminishing of those ancient complications and better quality of life for children. Two of the most popular systems are growing rods and Vertical Expandable Prosthetic Titanium Rib (VEPTR); however these new systems has its own complications such as infections, skin and neurological damage and high rate of surgical interventions. Materials and Methods: An observational cross sectional study comparing patients with EOS diagnosis, who underwent surgical correction using growing rods or VEPTR systems between 2010 and 2016 in an IV level Orthopedics children Institute were evaluated. A non-probabilistic sampling was performed. Statistical analysis was performed with STATA v14 Statistics program. Results: 54 patients met inclusion criteria. Mean age at intervention were 6.6 and 6 years old for rods and VEPTR groups respectively. Mean Cobb angle was 62.9 for rods group and 66.4 for VEPTR. Gender distribution was as follows 7:3 and 6.5:4.5 for Rods and VEPTR. The groups were matched for every variable. Regarding the correction of the spine deformity, both systems achieved a statically significant value (Growing Rods p Conclusion: EOS is challenging for spine surgeon due to the complexity of patients and additional comorbidities. Nowadays elongations systems are the mainstay of treatment. Growing rods and VEPTR systems are the most widespread worldwide. Growing Rods appears to better correct deformity without increase in complications, making it a more efficient system. Current literature recommends surgery every 9-12 months in contrast with previous concept of every 6 months, obtaining same clinical outcome with lower complications rates. Introduction: There is preclinical data indicating that early decompression in spinal cord injury (SCI) can improve outcome. Fehlings et al has shown in the STASCIS study the there is an advantage in decompression under 24 hours in cervical spine fractures. Our objective was to evaluate the relative effectiveness of surgery done under 12 hours from traumatic SCI. Material and Methods: A retrospective review of all patients admitted to a level one trauma center with SCI between 01/2006 to 02/2017, we included patients who were surgically treated within 48 hours of admission with 6 month or more follow up. Patients’ medical records were reviewed for location of vertebra fracture, presence of acute spinal cord injury, mechanism of injury, associated injuries, time to surgery (group A: less than 12 hours, group B: 12-24 hours, group C: 24-48 hours), length of hospital stay, ASIA impairment scale before surgery, after surgery, and at long term follow up. The neurological outcome was compared to the results present in the STASCIS study. Results: 49 patients (35 males: 14 females) with SCI were admitted and surgically treated within 48 hours of admission. Mean age at admission was 36 years (range 15-79 years). The mean follow up was 30 months (range 7-110 months). 50% were injured in motor vehicle accident while 48% due to falls. 37 were operated within 12 hours (average- 5.5 hours (range 1.5-11), 7 were operated between 12-24 hours and 5 were operated after 24 hours. At long term follow up after surgery, 55% of patients with acute spinal cord injury had been improved in their ASIA scale. After Surgery, in group A 67.5% of patients improved in their ASIA score (P = 0.06 when compared to under 24 hours in the STASCIS study) with 41% with a 2 grade or more improvement in their ASIA scores (P Conclusion: Early surgical intervention should be advised for patients with acute spinal cord injury. Surgery under 12 hours from the trauma should be recommended at as it is associated with improved outcome. Introduction: Surgery is increasingly recommended as the preferred treatment strategy for patients with degenerative cervical myelopathy (DCM), as it can halt neurologic deterioration and significantly improve functional impairment, disability and quality of life. Despite objective post-operative clinical improvements, experience dictates that a proportion of patients remain dissatisfied with their outcome. Discrepancies between clinical measures and self-reported ratings of health status after surgery, often referred to as response shift, can be due changes in patients’ internal standards of measurement, values and/or conceptualization of quality of life. This study aims to investigate the presence of response shift in functional outcomes in patients undergoing surgery for DCM. Material and Methods: Four hundred and seventy-nine DCM patients were prospectively enrolled in the AOSpine-CSM-International study at 16 global sites. Functional impairment, disability and quality of life were evaluated at baseline and 1-year following surgery. Patients were also asked to complete the SF-36 questionnaire and to rate their general health status compared to one year ago (much better, somewhat better, the same, somewhat worse, much worse). Descriptive analyses were conducted to evaluate the concordance between achieving a clinically important improvement (MCID) in function (modified Japanese Orthopedic Association (mJOA) scale) and self-reported ratings of health status. Concordance was defined as achieving a MCID and reporting general health as somewhat better or much better, whereas discordance was defined as achieving a MCID and reporting general health as the same, somewhat worse or much worse. Logistic regression analysis was used to determine important differences between patients with discrepancies between their clinical measures and self-reported ratings and those without. Results: Four-hundred-one patients had complete follow-up data at 1-year and were included in this analysis. Based on patient self-reports, 55 patients were somewhat or much worse than a year ago, 82 patients were the same and 264 patients were somewhat or much better. Thirty-one percent of patients who reported being somewhat or much worse achieved a MCID on the mJOA. In addition, 56% of patients who indicated their health status was the same as one year ago exhibited clinically meaningful improvements in functional impairment. Univariate analyses indicated that there is an increased likelihood of observing a discrepancy between functional outcomes and self-reported ratings if the patient (1) exhibited less improvement in mJOA upper extremity scores (p = 0.071), (2) was older (p = 0.0073), (3) was a smoker (p = 0.082) and (4) achieved lower total mJOA scores at 1-year (p = 0.087). Following multivariate analysis, the most important factors were age and improvement in mJOA upper extremity scores. Conclusion: A response shift in functional outcomes was detected in patients undergoing surgery for DCM. Older patients, as well as those with smaller improvements in postoperative upper extremity scores, tend to report worsened or unchanged general health status, in spite of experiencing clinically significant improvement in overall post-operative function. Introduction: Presently, spine professionals use a static image to assist in surgical planning and patient education. However, the spine is not a static object. While the soft tissue anatomy of the spine is well elucidated using magnetic resonance imaging (MRI), the flexible, dynamic nature of the spine is difficult to visualize and portray, especially to patients. Therefore, the goal of this study was to implement spine kinematics and common degenerative pathologies in an interactive virtual reality (VR) program and determine its efficacy in improving patient education and communication. Material and Methods: We developed a library of digital 3D models of spinal anatomy that can be visualized and manipulated within a virtual environment. A generic healthy model of the spine was created using the Autodesk Maya® modeling software. Kinematics parameters were informed using published literature [1]. Clinical cases depicting degenerative pathology were likewise modeled after patient examples. These models were animated and exported to a Unity Game Engine application, which was run on a Samsung Gear VR headset. IRB approval was obtained and patients seen at the UCLA Spine Center were provided with the headset during their consultation. A survey was administered at the conclusion of the visit to quantify patient satisfaction and gauge the patients’ understanding of the relevant discussed anatomy. Results: Spine professionals can easily guide and educate patients regarding spinal anatomy and degenerative pathologies in an immersive VR environment. The scenario’s that present foraminal stenosis and central canal stenosis due to disk bulging and ligament hypertrophy were reported to be most useful by patients. Likewise, the kinematic model of the spine allowing visualization of lumbar flexion and extension enabled physician to better explain these dynamic states of the spine to the patients. No adverse events were observed and preliminary data from surveys demonstrates high patient satisfaction with the educational content and experience. Conclusion: Unlike static 2D medical images, VR allows people to immerse themselves in an educational environment that is difficult to create in real life, such as the inside of a spinal canal. The visualizations included color-coded anatomy, animations, and interactive movement based on real patient information. Patients not only improved their understanding of the pathology, but the technology enabled patients to feel more confident overall about their diagnosis. Future work will determine if this understanding and confidence will translate to improved patient consent prior to surgical interventions, preparation for post-operation safety needs, and reduced readmissions [2, 3, 4]. Furthermore, our aim is to ultimately present patients with 3D VR models that are personalized with their pathology, which can then be used for surgical planning also by surgeons. References 1. White, Augustus A., and Manohar M. Panjabi. Clinical biomechanics of the spine. Philadelphia: Lippincott, 1978. Print. 2. Labhardt, Niklaus Daniel et al. Provider–patient interaction in rural Cameroon—How it relates to the patient’s understanding of diagnosis and prescribed drugs, the patient’s concept of illness, and access to therapy. Patient Education and Counseling, Volume 76, Issue 2, 196 - 201 3. Cho, R. N., Plunkett, B. A., Wolf, M. S., Simon, C. E. and Grobman, W. A. (2007), Health literacy and patient understanding of screening tests for aneuploidy and neural tube defects. Prenat. Diagn., 27: 463–467. doi:10.1002/pd.1712 4. Bollschweiler, Elfriede; Apitzsch, Jonas; Obliers, Rainer; Koerfer, Armin; Mönig Stefan P.; et al. Improving Informed Consent of Surgical Patients Using a Multimedia-Based Program?: Results of a Prospective Randomized Multicenter Study of Patients Before Cholecystectomy. Annals of Surgery. 248(2):205-211, AUG 2008. doi: 10.1097/SLA.0b013e318180a3a7 Introduction: The initial imaging of patients with thoracolumbar burst fractures and incomplete spinal cord injuries often starts with obtaining a CT scan. While surgical intervention is often recommended1, obtaining an MRI prior to going to the operating room is at the discretion of the treating surgeon. MRI has been shown to be useful in determining the extent of soft-tissue damage in spinal trauma, but each study did not distinguish whether or not a spinal cord injury was present.2-4 Material and Methods: A survey of 127 spine surgeons was conducted to determine whether or not operative treatment plans were directly changed by the availability of MRI imaging studies in patients who had thoracolumbar burst fractures (T10-L1) and incomplete spinal cord injuries. The patients for this study (n = 10) were identified by searching the Department of Radiology’s diagnosis database for the diagnosis of burst fracture and both CT and MRI studies that were obtained prior to any surgical interventions. The admission history and physical exam for each of these patients was also reviewed to determine whether or not an incomplete spinal cord injury was present at the time of initial evaluation. The axial and sagittal CT studies as well as the initial history and physical for each of these 10 patients were deidentified and presented to the surgeons participating in the survey. Each participant was then asked to formulate a surgical plan. Once a surgical plan was formulated based on the CT scan, they were asked whether or not an MRI was desired and why. The axial and sagittal T2 MRI scan images were then presented. The surgeons were then asked whether or not this altered their initial surgical plan. Results: Of those surveyed, 66% were practicing as Orthopaedic and 34% as Neurosurgery trained spine surgeons. The majority (66%) of those responding to the survey have been in practice greater than 10-years. In the patient population presented, after reviewing the initial CT scan, 41% of respondents stated that they would like to obtain an MRI before proceeding to the operating room. This was desired to evaluate for discoligamentous injuries adjacent to the fractured segment, to determine if anterior only treatment is sufficient or due to suspicion of adjacent bony injury not evident on CT scan. After reviewing the MRI, 19% of all respondents stated that their previous surgical plan had been changed. Out of the 41% of respondents that desired a MRI scan after evaluating the CT scan, 45% stated that they had changed their surgical plan. Conclusion: The majority of the time (59%), respondents did not feel that an MRI was necessary for operative planning. Eighty-one percent of the time, MRI made no difference in planned treatment. The MRI was most often desired due to it being the standard protocol of the treating institution or to evaluate the posterior ligamentous complex. In conclusion, the operative treatment of patients with thoraco-lumbar burst fractures is changed in 1 out of 5 patients by imaging the injured levels with an MRI. Introduction: Spinal segment arthrodesis has become a widely accepted treatment for degenerative disorders of the lumbar spine. However spinal fusion alters the normal biomechanics of the spine and eliminates mobile segments causing overload of adjacent segments. In recent years, increasing importance in degenerative decompensation of the adjacent segment after lumbar fusion is attached to spino-pelvic malalignment. At the same time, according to some authors, the overload of the adjacent segment in conditions of a PI-LL parameter mismatch exceeding 11° leads to the ASD development. Material and Methods: This prospective study evaluated 86 patients who were treated from 2011 to 2013 for lumbar canal stenosis with TLIF. All patients had preop PI-LL mismatch greater than 11° with no other global balance disturbance (SVA Results: There were no statistically significant differences in operative time, blood loss and postop pain level between two groups. Comparison of the pre- and postoperative values within the groups showed significant differences in the second group for lumbar lordosis (p = 0.037). Summary in the I group symptomatic ASD was found in 14 cases (33.3%) during all follow-up period with 85.7% frequently of revision surgery. In the II group symptomatic ASD was identified in 2 patients (4.5%), one of them needed revision surgery. Conclusion: The described technique of operative treatment allows to achieve an increase in lumbar lordosis up to 10 degrees on one segment without increasing surgery trauma. This technique has shown a statistically significant (p = 0.012) prevention of ASD development in patients with PI-LL mismatch. Introduction: Vitamin B12 (cobalamin) deficiency can lead to a form of myelopathy known as subacute combined degeneration (SCD), which is characterized by damage to the dorsal and lateral columns of the spinal cord. Nitrous oxide is an inhaled anesthetic which irreversibly oxidizes the cobalt ion of vitamin B12, interfering with its function as a key coenzyme. Although a number of individual case reports have described the development of SCD following nitrous oxide anesthesia, it is unknown what factors predispose patients to SCD or are predictive of long-term recovery. In this study, we conduct a systematic literature review of reported cases of SCD following nitrous oxide anesthesia. Materials and Methods: A medical librarian performed a comprehensive search of multiple databases after consultation with the lead authors and a Medical Subject Heading (MeSH) analysis of key articles provided by the research team. The final searches retrieved a total of 339 references, which were pooled in EndNote and de-duplicated to 148. 4 further studies were identified by examining the reference lists of all included articles. Two separate screeners (KP and AN) evaluated the titles, abstracts, and full texts of the eligible articles in a standardized manner. The following data were extracted from each eligible article: patient characteristics, the duration of nitrous oxide anesthesia, neurological findings, laboratory values, imaging factors, treatment, and recovery. Mann-Whitney U tests, Independent T-tests, and Chi Square tests were performed, with significance considered at p Results: Our systematic search identified 152 unique articles. After screening these articles by title, abstract, and full-text, a total of 32 studies, reporting a total of 39 cases of nitrous oxide-induced SCD, were deemed relevant. These cases included 22 male patients and 17 female patients, with an average age of 51.3 years (SD 17.6). An etiology for subclinical deficiency, including pernicious anemia, atrophic gastritis, intestinal metaplasia, ileal resection, Crohn’s Disease, and nutritional deficiency, was determined in 31 reports, while there was no evidence of pre-operative deficiency in 8 reports. Duration of nitrous oxide exposure was described in 19 reports, and ranged from 30 minutes to 11 hours. Univariate analysis failed to find any association between post-operative recovery and age (p = 0.41), sex (p = 0.48), positive MRI findings (p = 0.42), and post-operative serum B12 (p = 0.96). However, there was a tendency of post-operative high Hemoglobin (p = 0.09) and post-operative high Mean Corpuscular Volume (p = 0.14) to relate with worse neurological recovery. Conclusions: Given the high prevalence of subclinical B12 deficiency and the potential for relatively short exposures to nitrous oxide to precipitate SCD, it is imperative that surgeons remain aware of this process. In patients with postsurgical myelopathy, the physician should evaluate serum B12 and consider the possibility that nitrous oxide could cause a subclinical B12 deficiency to become overt. Further, we recommend screening patients undergoing surgery for risk factors or signs of B12 deficiency to avoid post-operative myelopathy. Since we were limited by a small cohort in this study, the trends identified here will be important to study further with larger patient populations.