The biomechanical effect of lumbopelvic distance reduction on reconstruction after total sacrectomy: a comparative finite element analysis of four techniques.

BACKGROUND CONTEXT: Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. However, to achieve long-term clinical stability, bony fusion between the lumbar spine and the pelvic ring is crucial. Reduction of the lumbopelvic distance can promote successful bony fusion. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet. PURPOSE: To evaluate and compare the biomechanical characteristics of four different LPRTs while considering the effect of LPDR. STUDY DESIGN/SETTING: A comparative finite element (FE) study. METHODS: The FE models following total sacrectomy were developed to analyze four different LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed in flexion, extension, lateral bending, and axial rotation. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress state at the bone-implant interface and within the rods. RESULTS: Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR

Complication Pattern of Sacral Primary Tumor Resection: A Study on the Risk Factors of Surgical Site Infection and Bowel or Bladder Dysfunction and Their Associations with Length of Hospital Stay.

STUDY DESIGN: Retrospective open cohort study. PURPOSE: The current study aimed to explore the pattern of complications after primary sacral tumor resection, to investigate the possible effect of several perioperative parameters on the development of complications, and to identify which complications are associated with the length of hospital stay (LOS). OVERVIEW OF LITERATURE: Primary sacral tumor (pST) resection is associated with a high complication rate. However, the number of studies on these complications and their effect on LOS is limited. METHODS: The clinical data of 140 patients with pST surgeries and 106 subsequent patients with local recurrence surgeries in four subgroups (index surgery, local recurrence surgery, malignant, and benign tumor) were prospectively collected and analyzed. The prognostic value of several perioperative factors on the development of surgical site infection (SSI), bowel and bladder dysfunction (BBD), and LOS was investigated using the logistic and linear regression models. RESULTS: The overall complication rates were 61.2% after index surgeries and 50.9% after local recurrence surgeries. The most frequent complications were SSI, vegetative dysfunction, urinary tract infections, and neurological deterioration. Age >55 years, malignant tumors, and red blood cell transfusion had a predictive effect on the development of SSI in the logistic model (p<0.01, R2=0.43). Bilateral S2 or S3 resection commonly caused postoperative BBD (chi-square test=62.5, degrees of freedom=4, p<0.001). In the multiple linear regression model, wound dehiscence, BBD, systemic and urinary tract infection, cerebrospinal fluid leak, and neurologic deterioration were associated with a significantly long LOS (p<0.01, R2=0.62). CONCLUSIONS: Surgical resection of pSTs has a high complication rate. Its common complications are SSI and BBD, both of which can have a significant influence on global therapeutic outcome. Malignant tumor diagnosis, old age, and red blood cell transfusion can remarkably increase the risk of SSI. Further, the development of BBD is significantly associated with the number of resected sacral nerve roots. By decreasing perioperative complications, LOS can decrease significantly.

Complication Pattern After Percutaneous Cement Discoplasty: Identification of Factors Influencing Reoperation and Length of Hospital Stay.

OBJECTIVE: Percutaneous cement discoplasty (PCD) was introduced to treat symptomatic vertical instability of the lumbar spine in a minimally invasive way. The aim of the present study was to analyze the complication pattern after PCD and to identify factors that predict the chance of cement leakage, reoperation, and length of hospital stay (LOS). METHODS: patients were treated with PCD within the study period. Clinical features and complications were analyzed by applying descriptive statistics, whereas perioperative factors predictive of cement leakage, reoperation, and LOS were identified by regression models. RESULTS: Cement leakage rate was 30.4% in the total cohort; however, only fifth of them were symptomatic. Cement leakage itself did not have a significant influence on clinical outcome. Other complications and nonsurgical adverse events were registered only in 2.0% of cases. Age, subcutaneous fat tissue thickness, low viscosity cement, lower level of surgeon's experience and the number of operated levels were identified as risk factors of cement leakage (P < 0.01; c-index = 0.836). Type of procedure, Charlson comorbidity score, reoperation, and nonsurgical adverse events significantly increased the LOS (P < 0.01). Cement leakage, early surgical practice, and increased subcutaneous fat tissue thickness were risk factors for reoperation (P < 0.01; c-index = 0.72). CONCLUSIONS: PCD is a relatively safe and effective procedure for treating spinal instability caused by advanced-stage disc degeneration characterized by vacuum phenomenon. Cement leakage is not uncommon but is only a radiologic complication without clinical consequences in most cases. On the other hand, it can increase the LOS and is a significant risk factor for reoperation.

Potential molecular mechanism in self-renewal is associated with miRNA dysregulation in sacral chordoma - A next-generation RNA sequencing study.

Background: Chordoma, the most frequent malignant primary spinal neoplasm, characterized by a high rate of recurrence, is an orphan disease where the clarification of the molecular oncogenesis would be crucial to developing new, effective therapies. Dysregulated expression of non-coding RNAs, especially microRNAs (miRNA) has a significant role in cancer development. Methods: Next-generation RNA sequencing (NGS) was used for the combinatorial analysis of mRNA-miRNA gene expression profiles in sacral chordoma and nucleus pulposus samples. Advanced bioinformatics workflow was applied to the data to predict miRNA-mRNA regulatory networks with altered activity in chordoma. Results: A large set of significantly dysregulated miRNAs in chordoma and their differentially expressed target genes have been identified. Several molecular pathways related to tumorigenesis and the modulation of the immune system are predicted to be dysregulated due to aberrant miRNA expression in chordoma. We identified a gene set including key regulators of the Hippo pathway, which is targeted by differently expressed miRNAs, and validated their altered expression by RT-qPCR. These newly identified miRNA/RNA interactions are predicted to have a role in the self-renewal process of chordoma stem cells, which might sustain the high rate of recurrence for this tumor. Conclusions: Our results can significantly contribute to the designation of possible targets for the development of anti-chordoma therapies.

Genetic variants of interleukin 1B and 6 are associated with clinical outcome of surgically treated lumbar degenerative disc disease.

BACKGROUND: Successfully surgically treating degenerative disc diseases can be challenging to the spine surgeons, the long-term outcome relies on both the physical and mental status of the patient before and after treatment. Numerous studies underlined the role of inflammatory cytokines - like interleukin 1B and 6 - in the development of chronic diseases such as failed back surgery syndrome (FBSS) and major depressive disorder (MDD) which alter the outcome after spinal surgery. Our aim was to evaluate the associations of IL6 and IL1B gene polymorphisms with the long-term outcome of degenerative lumbar spine surgeries. METHODS: An international genetical database (GENODISC) was combined with our institute's clinical database to create a large pool with long term follow up data. Altogether 431 patient's data were analysed. Patient reported outcome measures and surgical outcome was investigated in association with IL1B and IL6 SNPs with the help of 'SNPassoc' R genome wide association package. RESULTS: Interleukin 1B variants analysis confirmed association with improvement of pain after surgery on individual SNP level and on haplotype level, moreover relationship with patient reported outcome and preoperative level of depression was found on individual SNP level. IL6 variants were associated with preoperative depression, somatization and with subsequent surgery. CONCLUSION: Understanding the complexity of spinal surgery patients' long-term well-being is crucial in effectively treating chronic debilitating somatic diseases and the associated mental illnesses. Further studies should investigate more comprehensively the linkage of chronic physical and mental illnesses focusing on their simultaneous treatment.

A novel three-dimensional volumetric method to measure indirect decompression after percutaneous cement discoplasty.

PURPOSE: Percutaneous cement discoplasty (PCD) is a minimally invasive surgical option to treat patients who suffer from the consequences of advanced disc degeneration. As the current two-dimensional methods can inappropriately measure the difference in the complex 3D anatomy of the spinal segment, our aim was to develop and apply a volumetric method to measure the geometrical change in the surgically treated segments. METHODS: Prospective clinical and radiological data of 10 patients who underwent single- or multilevel PCD was collected. Pre- and postoperative CT scan-based 3D reconstructions were performed. The injected PMMA (Polymethylmethacrylate) induced lifting of the cranial vertebra and the following volumetric change was measured by subtraction of the geometry of the spinal canal from a pre- and postoperatively predefined cylinder. The associations of the PMMA geometry and the volumetric change of the spinal canal with clinical outcome were determined. RESULTS: Change in the spinal canal volume (ΔV) due to the surgery proved to be significant (mean ΔV = 2266.5 ±â€¯1172.2 mm3, n = 16; p = 0.0004). A significant, positive correlation was found between ΔV, the volume and the surface of the injected PMMA. A strong, significant association between pain intensity (low back and leg pain) and the magnitude of the volumetric increase of the spinal canal was shown (ρ = 0.772, p = 0.009 for LBP and ρ = 0.693, p = 0.026 for LP). CONCLUSION: The developed method is accurate, reproducible and applicable for the analysis of any other spinal surgical method. The volume and surface area of the injected PMMA have a predictive power on the extent of the indirect spinal canal decompression. The larger the ΔV the higher clinical benefit was achieved with the PCD procedure. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: The developed method has the potential to be integrated into clinical software's to evaluate the efficacy of different surgical procedures based on indirect decompression effect such as PCD, anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), oblique lumbar interbody fusion (OLIF), extreme lateral interbody fusion (XLIF). The intraoperative use of the method will allow the surgeon to respond if the decompression does not reach the desired level.

Global Treatment Outcome after Surgical Site Infection in Elective Degenerative Lumbar Spinal Operations.

Background: Surgical site infection (SSI) is a serious complication after routine lumbar spinal operations, and its effect on global treatment outcome (GTO) is less reported. The aim of the current study was to measure the impact of SSI on outcome, which was evaluated with patient reported outcome measures (PROMs) and patients' subjective judgment (GTO). Methods: A total of 910 patients underwent primary a single- or two-level lumbar decompression or instrumented fusion surgical procedure. Patients completed Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Core Outcome Measurement Index (COMI) at baseline and at two-year follow-up. The rate of improvement in PROMs was measured for the total cohort and the group of patients with SSI. Patients evaluated GTO on a five-point Likert scale. This study was approved by the Scientific and Research Ethics Committee of the Medical Research Council (number: 29970-3/2015/EKU) and the Institutional Review Board. Results: Regardless of the presence of SSI, significant improvement was measured in all PROMs without any difference in the rate of change between the clinical subgroups (non-SSI vs. SSI, dODI: p = 0.370, dCOMI: p = 0.383, dVAS: p = 0.793). In the total cohort, 87.3% of patients reported good outcome (N% = 87.3%). After an SSI, however, more patients (25.7%) reported poor outcome compared with those without the complication (chi-square test: value = 5.66; df = 1; p = 0.017; odds ratio = 2.49). Conclusions: Patients with successfully treated SSI can expect as good objective clinical result as patients without SSI while the subjective treatment outcome can be worse. The GTO could also be improved in complicated cases, however, with more extensive peri-operative patient education and information considering the patients' expectations, too.

A Novel Three-Dimensional Computational Method to Assess Rod Contour Deformation and to Map Bony Fusion in a Lumbopelvic Reconstruction After En-Bloc Sacrectomy.

Introduction: En-bloc resection of a primary malignant sacral tumor with wide oncological margins impacts the biomechanics of the spinopelvic complex, deteriorating postoperative function. The closed-loop technique (CLT) for spinopelvic fixation (SPF) uses a single U-shaped rod to restore the spinopelvic biomechanical integrity. The CLT method was designed to provide a non-rigid fixation, however this hypothesis has not been previously tested. Here, we establish a computational method to measure the deformation of the implant and characterize the bony fusion process based on the 6-year follow-up (FU) data. Materials and Methods: Post-operative CT scans were collected of a male patient who underwent total sacrectomy at the age of 42 due to a chordoma. CLT was used to reconstruct the spinopelvic junction. We defined the 3D geometry of the implant construct. Using rigid registration algorithms, a common coordinate system was created for the CLT to measure and visualize the deformation of the construct during the FU. In order to demonstrate the cyclical loading of the construct, the patient underwent gait analysis at the 6th year FU. First, a region of interest (ROI) was selected at the proximal level of the construct, then the deformation was determined during the follow-up period. In order to investigate the fusion process, a single axial slice-based voxel finite element (FE) mesh was created. The Hounsfield values (HU) were determined, then using an empirical linear equation, bone mineral density (BMD) values were assigned for every mesh element, out of 10 color-coded categories (1st category = 0 g/cm3, 10th category 1.12 g/cm3). Results: Significant correlation was found between the number of days postoperatively and deformation in the sagittal plane, resulting in a forward bending tendency of the construct. Volume distributions were determined and visualized over time for the different BMD categories and it was found that the total volume of the elements in the highest BMD category in the first postoperative CT was 0.04 cm3, at the 2nd year, FU was 0.98 cm3, and after 6 years, it was 2.30 cm3. Conclusion: The CLT provides a non-rigid fixation. The quantification of implant deformation and bony fusion may help understate the complex lumbopelvic biomechanics after sacrectomy.

Correction to: Association of vitamin D receptor gene polymorphisms with disc degeneration.

Unfortunately, the following reference was missed out in the original publication.

Geometrical accuracy evaluation of an affordable 3D printing technology for spine physical models.

OBJECTIVE: The aim of the study is to develop a workflow to establish geometrical quality criteria for 3D printed anatomical models as a guidance for selecting the most suitable 3D printing technologies available in a clinical environment. METHODS: We defined the 3D geometry of a 25-year-old male patient's L4 vertebra and the geometry was then printed using two technologies, which differ in printing resolution and affordability: Fused Deposition Modelling (FDM) and Digital Light Processing (DLP). In order to measure geometrical accuracy, the 3D scans of two physical models were compared to the virtual input model. To compare surface qualities of these printing technologies we determined surface roughness for two regions of interest. Finally, we present our experience in the clinical application of a physical model in a congenital deformity case. RESULTS: The analysis of the distribution of the modified Hausdorff distance values along the vertebral surface meshes (99% of values <1 mm) of the 3D printed models provides evidence for high printing accuracy in both printing techniques. Our results demonstrate that the surface qualities, measured by roughness are adequate (~99% of values <0.1 mm) for both physical models. Finally, we implemented the FDM physical model for surgical planning. CONCLUSION: We present a workflow capable of determining the quality of 3D printed models and the application of a high quality and affordable 3D printed spine physical model in the pre operative planning. As a result of the visual guidance provided by the physical model, we were able to define the optimal trajectory of the screw insertion during surgery.

Development of a Computer-Aided Design and Finite Element Analysis Combined Method for Affordable Spine Surgical Navigation With 3D-Printed Customized Template.

Introduction: Revision surgery of a previous lumbosacral non-union is highly challenging, especially in case of complications, such as a broken screw at the first sacral level (S1). Here, we propose the implementation of a new method based on the CT scan of a clinical case using 3D reconstruction, combined with finite element analysis (FEA), computer-assisted design (CAD), and 3D-printing technology to provide accurate surgical navigation to aid the surgeon in performing the optimal surgical technique by inserting a pedicle screw at the S1 level. Materials and Methods: A step-by-step approach was developed and performed as follows: (1) Quantitative CT based patient-specific FE model of the sacrum was created. (2) The CAD model of the pedicle screw was inserted into the sacrum model in a bicortical convergent and a monocortical divergent position, by overcoming the geometrical difficulty caused by the broken screw. (3) Static FEAs (Abaqus, Dassault Systemes) were performed using 500 N tensile load applied to the screw head. (4) A template with two screw guiding structures for the sacrum was designed and manufactured using CAD design and 3D-printing technologies, and investment casting. (5) The proposed surgical technique was performed on the patient-specific physical model created with the FDM printing technology. The patient-specific model was CT scanned and a comparison with the virtual plan was performed to evaluate the template accuracy Results: FEA results proved that the modified bicortical convergent insertion is stiffer (6,617.23 N/mm) compared to monocortical divergent placement (2,989.07 N/mm). The final template was created via investment casting from cobalt-chrome. The template design concept was shown to be accurate (grade A, Gertzbein-Robbins scale) based on the comparison of the simulated surgery using the patient-specific physical model and the 3D virtual surgical plan. Conclusion: Compared to the conventional surgical navigation techniques, the presented method allows the consideration of the patient-specific biomechanical parameters; is more affordable, and the intraoperative X-ray exposure can be reduced. This new patient- and condition-specific approach may be widely used in revision spine surgeries or in challenging primary cases after its further clinical validation.

Association of vitamin D receptor gene polymorphisms with disc degeneration.

PURPOSE: Numerous candidate genes and single-nucleotide polymorphisms (SNPs) have been identified in the background of lumbar disc degeneration (LDD). However, in most of these underpowered studies, definitions of LDD are inconsistent; moreover, many of the findings have not been replicated and are contradictory. Our aim was to characterize LDD by well-defined phenotypes and possible endophenotypes and analyse the association between these and candidate vitamin D receptor (VDR) gene polymorphisms on a large (N = 1426) dataset. METHODS: Seven candidate VDR SNPs were genotyped. Individual association, haplotype and gene-gene interaction analyses were performed. All degenerative endophenotypes were significantly associated with one or more candidate VDR gene variants. RESULTS: Haplotype analyses confirmed the association between the 3'-end VDR variants (BsmI, ApaI, TaqI) and Modic changes as well as the relationship of 5'-end variants (Cdx2, A1012G) with endplate defects. We also found significant interactions between the 3'- and 5'-end regulatory regions and endplate defects. Based on our results, VDR and its gene variants are highly associated with specific degenerative LDD endophenotypes. CONCLUSION: Understanding relationships between phenotype and gene variants is crucial for describing the pathways leading to the multifactorial, polygenic degeneration process and LDD-related conditions. These slides can be retrieved under Electronic Supplementary Material.

Attitude of spine surgeons towards the application of 3D technologies - a survey of AOSpine members.

BACKGROUND AND PURPOSE: 3D technologies (3D virtual and physical model, 3D printing, computer aided engineering, finite element analysis based simulations) play an important role in personalized spine surgery. Objective - In collaboration with AOSpine a global, online survey-based study was performed in order to determine the acceptance rate and the factors which stand against the wider spread of 3D technologies. METHODS: A survey containing 21 questions was developed and divided into five pages, every page corresponding to one chapter. Our analysis is based on the responses of 282 spine surgeons from 57 countries. To interpret our results in a global context, we used the Human Development Index of the respondent's countries in comparisons. RESULTS: Significant difference between the AOSpine regions (p ≤ 0.05) was found, with the highest acceptance in Asia-Pacific region. There was no significant difference in acceptance score according to the field of spine surgery, or the surgical experience in years (p=0.77, and p=0.19). In the case of public practice, we found significantly higher acceptance compared to private and mixed (public and private) surgical practice (p ≤ 0.05). The acceptance of the technology varied based on the respondent's resident country's Human Development Index and was significantly different between "Medium" vs "Very high" (p = 0.0005) and "High" vs "Very high" (p=0.019) category. Significant positive correlation was found between the acceptance score and the HDI score (Spearman test, ρ = 0.37, p = 0.007). The main limitation factor was identified as the lack of information. CONCLUSION: There is high interest among spine surgeons towards the incorporation of 3D technologies into the clinical practice. Education, the healthcare system, and the economic environment plays a major role in acceptance. Our results provide the basis of a strategy to promote the application of 3D technologies.

Clinical presentation, management and outcomes of sacral metastases: a multicenter, retrospective cohort study.

BACKGROUND: Sacral metastases are rare and literature regarding their management is sparse. This multicenter, prospective, observational study aimed to determine health related-quality of life (HRQOL) and pain in patients treated for sacral metastases with surgery and/or radiation therapy (RT). The secondary objectives were to describe the adverse event (AE) profile and change in neurologic function in this population. METHODS: Twenty-three patients presenting with symptomatic sacral metastases were identified from the Epidemiology, Process and Outcomes of Spine Oncology (EPOSO) dataset, a prospective multicenter study on spinal metastases. Patients requiring surgery and/or RT between August 2013 and February 2017 were prospectively enrolled. HRQOL, assessed by the Spine Oncology Study Group Outcomes Questionnaire (SOSGOQv2.0), the Short Form-36 version 2 (SF-36v2), and the EuroQol-5Dimension (EQ-5D) was documented at baseline, 6 weeks, 3 and 6 months post-treatment. Pain numeric rating scale (NRS), AEs, lower extremities motor score (ASIA), and bowel and bladder function were also recorded. RESULTS: Eight patients underwent surgery ± RT and 15 patients underwent RT alone. Mean age was 59.3 (SD 11.7) years and 13 patients were female. At 6 months, 3 (37.5%) surgical patients and 2 (13.3%) RT patients were deceased. There was a trend showing that surgical patients had worse baseline HRQOL and pain. Pain NRS, EQ-5D, SOSGOQv2.0, and the mental component of the SF-36v2 showed improvement, irrespective of treatment (P>0.05). Ten AEs occurred in the surgical cohort, dominated by wound complications (n=3). Bowel and bladder function improved at 6 weeks in both groups. CONCLUSIONS: Surgical treatment and RT are both valid treatment options for symptomatic sacral metastases. Improvement in HRQOL can be expected with an acceptable AE rate.

Prognostic significance of human telomerase reverse transcriptase promoter region mutations C228T and C250T for overall survival in spinal chordomas.

BACKGROUND: Spinal chordomas, a subtype of primary spinal column malignancies (PSCM), are rare tumors with poor prognosis, and we have limited understanding of the molecular drivers of neoplasia. METHODS: Study design was a retrospective review of prospectively collected data with cross-sectional survival. Archived paraffin embedded pathologic specimens were collected for 133 patients from 6 centers within Europe and North America between 1987 and 2012. Tumor DNA was extracted and the human telomerase reverse transcriptase (hTERT) promoter was sequenced. The hTERT mutational status was correlated with overall survival (OS) and time to first local recurrence. RESULTS: Ninety-two chordomas, 26 chondrosarcomas, 7 osteosarcomas, 3 Ewing's sarcomas, and 5 other malignant spinal tumors were analyzed. Median OS following surgery was 5.8 years (95% CI: 4.6 to 6.9) and median time to first local recurrence was 3.9 years (95% CI: 2.5 to 6.7). Eight chordomas, 2 chondrosarcomas, 1 Ewing's sarcoma, and 1 other malignant spinal tumor harbored either a C228T or C250T mutation in the hTERT promoter. In the overall cohort, all patients with hTERT mutation were alive at 10 years postoperative with a median OS of 5.1 years (95% CI: 4.5 to 6.6) (P = 0.03). hTERT promoter mutation was observed in 8.7% of spinal chordomas, and 100% of chordoma patients harboring the mutation were alive at 10 years postoperative compared with 67% patients without the mutation (P = 0.05). CONCLUSIONS: We report for the first time that hTERT promoter mutations C228T and C250T are present in approximately 8.7% of spinal chordomas. The presence of hTERT mutations conferred a survival benefit and could potentially be a valuable positive prognostic molecular marker in spinal chordomas.

Indirect foraminal decompression and improvement in the lumbar alignment after percutaneous cement discoplasty.

PURPOSE: Percutaneous cement discoplasty (PCD) is a minimally invasive surgical procedure, that can provide a segmental stabilizing and indirect decompression effect in case of severely degenerated discs characterized by vacuum phenomenon. The objective of this study was to evaluate the effects of PCD on spinopelvic radiological parameters and their associations with the clinical outcome. METHODS: Retrospective analysis of prospectively collected dataset of 28 patients (112 lumbar segments) who underwent single- or multilevel PCD was performed. Spinopelvic, intrasegmental and intersegmental parameters were measured on lumbar X-rays pre-, postoperatively and 6 months after the surgery. Correlations between radiological parameters and clinical outcome data were determined. RESULTS: Sacral slope significantly increased (p < .001), and pelvic tilt (p < .05) was decreased after the PCD procedure. Segmental and total lordosis (p < .05, p < .05) disc and foraminal height showed significantly increase (p < .001, p < .001) after procedure. Pain and disability (ODI) significantly decreased due to PCD. An association was found between postoperative increase in SS and improvement in ODI (r = 0.39, p < .05). The change in low back pain was correlated with segmental scoliosis correction (p < .001). Moderate correlation was detected between the increase in disc height and ODI (p < .05) as well as leg pain (p < .01). CONCLUSION: PCD is an effective minimally invasive technique to treat axial pain and disability related to severe lumbar disc degeneration. Our study shows that an improvement in lumbar alignment and a significant indirect foraminal decompression could be achieved with the procedure. These changes can significantly contribute to the pain relief and increase in the patients' functional capacity. These slides can be retrieved under Electronic Supplementary Material.

[Change of paradigm in the surgical treatment of metastatic diseases of the bone. Part II. Treatment of spinal metastases]. / Paradigmaváltás a csontmetasztázisok sebészetében. II. Gerincmetasztázisok kezelése.

The incidence of spinal metastases is constantly growing, but due to the advancements in oncologic treatment methods, the survival and the quality of life of the patients are persistently improving. Choosing the optimal treatment method is essential, and several factors should be considered: type of the primary tumor, segmental stability, the symptoms caused by the metastasis and the general condition of the patient. Using modern radiotherapeutic methods combined with minimally invasive surgical techniques (minimally invasive stabilization, separation surgery) in the majority of patients permits adequate local control with low complication rate. In our review, we describe the state-of-the-art, modern spinal metastasis treatment options based on the recently published evidence. Orv Hetil. 2018; 159(8): 297-302.

Risk factors of non-specific spinal pain in childhood.

PURPOSE: Non-specific spinal pain can occur at all ages and current evidence suggests that pediatric non-specific spinal pain is predictive for adult spinal conditions. A 5-year long, prospective cohort study was conducted to identify the lifestyle and environmental factors leading to non-specific spinal pain in childhood. MATERIALS AND METHODS: Data were collected from school children aged 7-16 years, who were randomly selected from three different geographic regions in Hungary. The risk factors were measured with a newly developed patient-reported questionnaire (PRQ). The quality of the instrument was assessed by the reliability with the test-retest method. Test (N = 952) and validity (N = 897) datasets were randomly formed. Risk factors were identified with uni- and multivariate logistic regression models and the predictive performance of the final model was evaluated using the receiver operating characteristic (ROC) method. RESULTS: The final model was built up by seven risk factors for spinal pain for days; age > 12 years, learning or watching TV for more than 2 h/day, uncomfortable school-desk, sleeping problems, general discomfort and positive familiar medical history (χ2 = 101.07; df = 8; p < 0.001). The probabilistic performance was confirmed with ROC analysis on the test and validation cohorts (AUC = 0.76; 0.71). A simplified risk scoring system showed increasing possibility for non-specific spinal pain depending on the number of the identified risk factors (χ2 = 65.0; df = 4; p < 0.001). CONCLUSION: Seven significant risk factors of non-specific spinal pain in childhood were identified using the new, easy to use and reliable PRQ which makes it possible to stratify the children according to their individual risk. These slides can be retrieved under Electronic Supplementary Material.