Cumhur Oner
Utrecht University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Cumhur Oner.
Spine | 2013
Alexander R. Vaccaro; Cumhur Oner; Christopher K. Kepler; Marcel F. Dvorak; Klaus J. Schnake; Carlo Bellabarba; Max Reinhold; Bizhan Aarabi; Frank Kandziora; Jens R. Chapman; R. Shanmuganathan; Michael G. Fehlings; Luiz Roberto Vialle
Study Design. Reliability and agreement study, retrospective case series. Objective. To develop a widely accepted, comprehensive yet simple classification system with clinically acceptable intra- and interobserver reliability for use in both clinical practice and research. Summary of Background Data. Although the Magerl classification and thoracolumbar injury classification system (TLICS) are both well-known schemes to describe thoracolumbar (TL) fractures, no TL injury classification system has achieved universal international adoption. This lack of consensus limits communication between clinicians and researchers complicating the study of these injuries and the development of treatment algorithms. Methods. A simple and reproducible classification system of TL injuries was developed using a structured international consensus process. This classification system consists of a morphologic classification of the fracture, a grading system for the neurological status, and description of relevant patient-specific modifiers. Forty cases with a broad range of injuries were classified independently twice by group members 1 month apart and analyzed for classification reliability using the Kappa coefficient (&kgr;). Results. The morphologic classification is based on 3 main injury patterns: type A (compression), type B (tension band disruption), and type C (displacement/translation) injuries. Reliability in the identification of a morphologic injury type was substantial (&kgr;= 0.72). Conclusion. The AOSpine TL injury classification system is clinically relevant according to the consensus agreement of our international team of spine trauma experts. Final evaluation data showed reasonable reliability and accuracy, but further clinical validation of the proposed system requires prospective observational data collection documenting use of the classification system, therapeutic decision making, and clinical follow-up evaluation by a large number of surgeons from different countries. Level of Evidence: 4
Tissue Engineering Part A | 2008
Moyo C. Kruyt; Joost D. de Bruijn; Jeroen Rouwkema; Clemens van Blitterswijk; Cumhur Oner; Ab J. Verbout; Wouter J.A. Dhert
After decades of research, relatively little is known about the role of bone marrow stromal cells (BMSCs) for bone tissue engineering. Although homogeneous cell seeding is regarded optimal, cell survival in large constructs is unlikely, except for the very periphery. Also no minimal and optimal BMSC densities have been identified. An interesting development is the use of allogeneic BMSCs. These have not yet been compared directly to autologous BMSCs. Culture-expanded BMSCs of 10 Dutch milk goats were cryopreserved and peroperatively seeded on 7 mm cubic scaffolds of 65% porous biphasic calcium phosphate (BCP). A range of BMSC densities (per cm3 scaffold) were prepared of 8E2 (= 8 x 10(2)), 8E3, 8E4, 8E5, 8E6 (considered the standard), and 1.6E7. Each goat received a control without cells, the six densities, and an 8E6 allogeneic BMSCs construct intramuscularly. After 3, 5, and 7 weeks, fluorochrome markers were administrated. At 9 weeks, implants were retrieved. The BCP scaffolds appeared to be autoinductive as the controls (without BMSCs) showed some bone. Early bone formation (before 3 weeks) appeared only at the peripheral 2mm of the BMSC-seeded constructs; the later 5- and 9-week labels were found more centrally, suggesting bone migration to the center. There was a minimum of 8E4 and optimum of 8E6 BMSCs/cm3. Allogeneic cells yielded comparable new bone.
International Journal of Physical Medicine and Rehabilitation | 2015
Robyn Rubenstein; John D. Koerner; David Oh; Christopher K. Kepler; Frank K; ziora; R. Shanmuganathan; Marcel F. Dvorak; Bizhan Aarabi; Luiz Roberto Vialle; Cumhur Oner; Alex; er R Vaccaro
Numerous classification systems have been developed over the years to describe thoracolumbar injuries, each with their own benefits and limitations. None of these systems have been accepted however, as a universal, comprehensive system to classify these injuries. The AOSpine Thoracolumbar Injury Classification System has recently been developed in order to overcome some of the limitations of previous systems. An injury severity scoring system based on this system would be beneficial to clinicians when treating these complex injuries. This paper will review thoracolumbar injury classification systems, and describe the need for a new severity scoring system based on the AOSpine Thoracolumbar Injury Classification System.
World Neurosurgery | 2018
Ernest Wright; Federico Ricciardi; Mark P. Arts; Jacob M. Buchowski; Chun Kee Chung; Maarten H. Coppes; Alan Crockard; Bart Depreitere; Michael G. Fehlings; Norio Kawahara; Chong Suh Lee; Yee Leung; Antonio Martin-Benlloch; Eric M. Massicotte; Christian Mazel; Cumhur Oner; Wilco C. Peul; Nasir A. Quraishi; Yasuaki Tokuhashi; Katsuro Tomita; Christian Ulbricht; Jorrit-Jan Verlaan; Mike Wang; David Choi
BACKGROUND Indications for surgery for symptomatic spinal metastases have become better defined in recent years, and suitable outcome measures have been established against a changing backdrop of patient characteristics, tumor behavior, and oncologic treatments. Nonetheless, variations still exist in the local management of patients with spinal metastases. In this study, we aimed to review global trends and habits in the surgical treatment of symptomatic spinal metastases, and to examine how these have changed over the last 25 years. METHODS In this cohort study of consecutive patients undergoing surgery for symptomatic spinal metastases, data were collected using a secure Internet database from 22 centers across 3 continents. All patients were invited to participate in the study, except those unable or unwilling to give consent. RESULTS There was a higher incidence of colonic, liver, and lung carcinoma metastases in Asian countries, and more frequent presentation of breast, prostate, melanoma metastases in the West. Trends in surgical technique were broadly similar across the centers. Overall survival rates after surgery were 53% at 1 year, 31% at 2 years, and 10% at 5 years after surgery (standard error 0.013 for all). Survival improved over successive time periods, with longer survival in patients who underwent surgery in 2011-2016 compared with those who underwent surgery in earlier time periods. CONCLUSIONS Surgical habits have been fairly consistent among countries worldwide and over time. However, patient survival has improved in later years, perhaps due to medical advances in the treatment of cancer, improved patient selection, and operating earlier in the course of disease.
European Journal of Trauma and Emergency Surgery | 2018
Livia E. V. M. de Guerre; Said Sadiqi; Loek P. H. Leenen; Cumhur Oner; Steven M. van Gaalen
Background This study aims to analyze the incidence and outcomes of bicycle-related injuries in hospitalized patients in The Netherlands. Methods Bicycle accidents resulting in hospitalization in a level-I trauma center in The Netherlands between 2007 and 2017 were retrospectively identified. We subcategorized data of patients involved in a regular bicycle, race bike, off-road bike or e-bike accident. The primary outcomes were mortality rate and incidence of multitrauma. Secondary outcomes were differences between bicycle subcategories. Independent risk factors were identified using multivariable logistic regression. All variables with a p value < 0.20 in univariable analysis were entered in multivariable analysis. Results We identified 1986 patients. The mortality rate after emergency room admission was 5.7%, and 41.0% were multitraumas. A higher age, multitrauma and cerebral haemorrhages were independent risk factors for in hospital mortality. Independent risk factors found for multitrauma were a higher age, two-sided trauma, e-bike accidents and cerebral haemorrhage. Conclusion Bicycle accidents resulting in hospitalization have a high mortality rate. Furthermore, a high incidence of multitrauma, fractures and cerebral haemorrhages were found. Considering the increasing incidence of bicycle accident victims needing hospital admission, new and more efficient prevention strategies are essential.
Biomaterials | 2006
Moyo C. Kruyt; Clayton E. Wilson; Joost D. de Bruijn; Clemens van Blitterswijk; Cumhur Oner; Abraham J. Verbout; Wouter J.A. Dhert
Journal of Biomedical Materials Research Part B | 2004
Moyo C. Kruyt; Wouter J.A. Dhert; Cumhur Oner; Clemens van Blitterswijk; Abraham J. Verbout; Joost D. de Bruijn
European Spine Journal | 2013
Wilco Jacobs; Sidney M. Rubinstein; Paul C. Willems; Wouter A. Moojen; Ferran Pellisé; Cumhur Oner; Wilco C. Peul; Maurits W. van Tulder
BMJ Open | 2011
Paul Willems; Rob A. de Bie; Cumhur Oner; René M. Castelein; Marinus de Kleuver
Transplantation | 2004
Moyo C. Kruyt; Wouter J.A. Dhert; Cumhur Oner; Clemens van Blitterswijk; Abraham J. Verbout; Joost D. de Bruijn