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<ul><li><p> Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&amp;JOURNAL - quarterly december 2012 - Vol. 24 - N3-4</p><p>Focus 9517th ArgoSpine Symposium Scientific Book</p><p>LECTURE Day 1/ 9:00&gt;9:10</p><p>Dynamic fixation of the cervical spine</p><p>Dynamic fixation of the cervical spineJ.M. Casamitjana FerrandizUniversity Hospital, Vall dHebron, Barcelona, Spain</p><p>Anterior cervical spine surgery was introduced in the late 1950s</p><p>by Smith and Robinson and by Cloward. The goals of this</p><p>surgery include decompression of neural structures, reduction</p><p>of deformity, immediate stability, and creation of a conducive</p><p>environment for osseous fusion to occur. Recently, anterior plating</p><p>systems have been used in the hope of improving outcomes</p><p>following anterior cervical discectomy or corpectomy for degen-</p><p>erative, traumatic, and oncologic disorders. Proponents of plating</p><p>systems have cited numerous advantages, including earlier</p><p>patient mobilization, cost-effectiveness, a decreased need for</p><p>orthotics, a diminished rate of graft dislodgment and migration,</p><p>superior fusion rates, immediate stabilization, and the preven-</p><p>tion of spinal deformity. These potential benefits are much more</p><p>evident in patients who undergo multilevel surgery, such as cor-</p><p>pectomy and reconstruction, than those who undergo single-</p><p>level surgery. The designs of anterior cervical plates have</p><p>evolved substantially. The initial plate designs required bicor-</p><p>tical fixation, as the screws were not locked to the</p><p>plate. Constrained systems, in which the screw locked to the</p><p>plate, enabled unicortical fixation and reduced the problem of</p><p>screw back-out. More recently, pseudarthrosis has been noted</p><p>in association with static plates, which had been thought to</p><p>bridge and unload the interface between a subsided graft and</p><p>the end plate. Dynamic cervical plates were developed in</p><p>response to this problem. Rotationally dynamic plates allow the</p><p>screws to pivot or toggle yet continue to prevent screw back-</p><p>out. Translational dynamic plates not only allow the screws to</p><p>pivot but also to slide vertically in the plate.</p><p>Graft subsidence is common during healing after anterior</p><p>cervical fusion surgery. Dynamic plates, in theory, allow con-</p><p>tinued contact between the graft and the end plate after graft</p><p>subsidence has occurred, thus improving the chance of</p><p>obtaining a fusion by maintaining a compressive load on the</p><p>graft. Subsidence and its effects on the stiffness of a plating</p><p>system have received little attention from both clinical and bio-</p><p>mechanical standpoints.</p><p>A major concern for spine surgeons is the effect of dynamic</p><p>plating on stability and clinical outcome, both in the immediate</p><p>postoperative period and the long term. For one or two-level</p><p>degenerative disease, the type of plating system used is pri-</p><p>marily dependent on surgeon preference as the existing data</p><p>have supported static or dynamic systems equally. However, for</p><p>more extensive spondylotic decompression, oncologic resec-</p><p>tions, and traumatic injuries, some surgeons have advocated</p><p>the rigid, static constructs. We know of no study, either clinical</p><p>or biomechanical, that supports one system over another. Further</p><p>studies with an instability model, fatigue testing, and follow-up</p><p>of clinical outcomes will help to clarify the advantages and dis-</p><p>advantages of static and dynamic cervical plate designs. </p><p>Cervical plates, which minimize micromotion, have been demon-</p><p>strated to improve the fusion rate after the ACDF. Wang et al.</p><p>had reported a 0% nonunion for two-level ACDF with the use</p><p>of anterior cervical plating. Similarly, Bolesta et al. reported the</p><p>fusion rate of 97.5% when a cervical plate with segmental</p><p>fixation was used for two-level ACDF. However, one of the crit-</p><p>icisms of static cervical plates has been their rigidity which, in</p><p>theory, might distract the fusion site and prevent graft settling,</p><p>thereby increasing the chance for a pseudarthrosis. To address</p><p>this problem, dynamic plates have been developed. The theo-</p><p>retical advantage of dynamic plates is greater graft loading with</p><p>less stress shielding, which should increase fusion rates.</p><p>Nunley and colleagues performed a randomized controlled trial</p><p>of a heterogeneous mix of patients undergoing single or mul-</p><p>tilevel ACDF with rigid or dynamic fixation. They found no dif-</p><p>ference in outcomes for the groups undergoing single level</p><p>ACDF, but did find an advantage to dynamic instrumentation for</p><p>multilevel ACDF. In contrast, DuBois and colleagues reviewed</p><p>52 patients undergoing 2 and 3 level ACDF, comparing rigid</p><p>with dynamic anterior cervical plating. They found an increase</p><p>in the rate of nonunion when using the dynamic cervical plate</p><p>(P 5 .05). They measured the amount of construct settling over</p><p>1 to 2 years, and found no difference between the plating</p><p>systems, thus questioning the compressive properties of the</p><p>plate in vivo. Clinical outcomes were similar among the groups,</p><p>which led the investigators to conclude that the more expen-</p><p>sive dynamic plates do not offer any clear benefit compared</p><p>with rigid plates.</p><p>Anterior cervical plating is associated with adjacent level ossi-</p><p>fication which may be due to impingement from the plate on</p><p>the adjacent level disc space. Although comparative series have</p><p>shown no difference in incidence of this complication when</p><p>comparing rigid with dynamic cervical plating, special attention</p><p>must be paid to technique when using a dynamic plate. Park</p><p>and colleagues noted that the incidence of moderate to severe</p><p>adjacent level ossification was increased with less than 5 mm</p><p>Guest speakers lectures, oral presentations,clinical case presentations</p><p>FOCUS</p></li><li><p>Vol. 24 - N3-4 - quarterly december 2012 - ArgoSpine NEWS&amp;JOURNAL - Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6</p><p>96 Focus 17th ArgoSpine Symposium Scientific Book</p><p>of space between the adjacent disc and plate. The implication</p><p>for those using dynamic plates is that the subsidence of the</p><p>bodies and graft must be accounted for at the time of surgery,</p><p>as the plates may encroach on the adjacent levels in follow-up,</p><p>as the graft is compressed. This problem requires the surgeon</p><p>to know the amount of subsidence allowed by the plate, and</p><p>to understand the method of dynamization to optimize plate and</p><p>screw placement.</p><p>The clinical evidence for cervical dynamic plating remains mixed.</p><p>The literature supports a compressive role of the dynamic</p><p>cervical plate. However, there is little evidence for improvement</p><p>of fusion rates or clinical outcomes compared with rigid fixation.</p><p>The loss of segmental lordosis and potential for adjacent</p><p>segment impingement is a significant limitation of cervical</p><p>dynamic stabilization. Personal experience in more 200 cases</p><p>using ABC dynamic plate, the main problem was uncon-</p><p>trolled subsidence over the graft, adjacent disc lesion due the</p><p>progress of the plate, and kyphotic deformities, over 20% of</p><p>the series. In fractures instability was detected in extension after</p><p>graft bone height loosening. Moreover, the fusion time was not</p><p>shorter in our patients compared with the rigid plate cases. Due</p><p>to these reasons, I only use rigid plates. </p><p>/+/ AboutJ.M. Casamitjana Ferrandiz</p><p>Cervical Spine Pathology, Spine Surgery Unit,</p><p>Trauma and Rehabilitation, University Hospital,</p><p>Ciutat Sanitaria Universitaria, Vall dHebron</p><p>Psg. Vall dHebron 119-129</p><p>08035 Barcelona, Spain</p><p>Dr. Jos Casamitjana, Born August 20th, 1949 in Barcelona, he was</p><p>registered as an orthopedic surgeon in 1979. Since 1980 he has been</p><p>a staff member of the department of Traumatology and Orthopedic</p><p>surgery of the Vall dHebron Educational Hospitals in Barcelona. He</p><p>became initiated in cervical spine surgery in 1985 and for the past 20</p><p>years he has dedicated himself exclusively to this specialty. As of 1998</p><p>he is head of Cervical Spine Pathology within the Spine Surgery Unit</p><p>at the Vall dHebron Traumatology and Rehabilitation Hospital in</p><p>Barcelona. Besides contributing to many articles, he is frequently invited</p><p>as a speaker to national and international meetings. He is also involved</p><p>as a teacher in several international spine courses. As well as organ-</p><p>izing the CSRS-ES 2003 Annual Meeting in Barcelona, Dr. Jos</p><p>Casamitjana, was President of the Cervical Spine Research Society</p><p>from 2009 to 2011. He is the Chairman and organizer of the Societys</p><p>Instructional Hands on Cadaver Course and has organized nine cadaver</p><p>courses in Barcelona all extremely well rated by the participants.</p><p>LECTURE Day 1/ 9:10&gt;9:20</p><p>Dynamic fixation of the cervical spine</p><p>Biomechanics, kinematic concepts andmotion preservation with total discreplacementCdric Barrey1, Wafa Skalli21 Hospital P. Wertheimer, Lyon, France2 Laboratory of Biomechanics, Arts et Mtiers-ParisTech, Paris, France</p><p>Still considered as an emerging technology, cervical arthroplasty</p><p>has been progressively introduced to address the adverse</p><p>effects of traditional spinal fusion. In addition to provide clinical</p><p>results and outcomes at least as good as fusion, cervical total</p><p>disc replacement (TDR) intends to preserve intervertebral motion</p><p>with the ultimate objective to decrease the incidence of adjacent</p><p>degenerative disease.</p><p>The lecture will focus on the capacity of current TDR to restore</p><p>native kinematics of the cervical spine. Many questions are still</p><p>under investigations: what is the amount of motion actually</p><p>restored in vivo after cervical TDR? Does the TDR design influ-</p><p>ence the kinematics of the instrumented spine? What is the</p><p>quality of motion at adjacent levels? What are the benefits of</p><p>TDR versus arthrodesis for the adjacent levels? Are cervical</p><p>TDRs efficient to restore the sagittal balance of the cervical</p><p>spine? Are uncinatectomies necessary to preserve motion during</p><p>TDR surgery? Has the surgical technique any impact on the</p><p>biomechanical behaviour of the implanted device? Is there a</p><p>correlation between kinematics of TDR and clinical results?</p><p>Should we prefer hybrid or 2-levels TDR constructs?</p><p>Figures: Biomechanical investigational methods include experimental tests (left), numerical simulation methods (centre) and in vivo investigations (right).</p></li><li><p> Argospine and Springer-Verlag France 2012 - DOI 10.1007/s12240-012-0066-6 - ArgoSpine NEWS&amp;JOURNAL - quarterly december 2012 - Vol. 24 - N3-4</p><p>Focus 9717th ArgoSpine Symposium Scientific Book</p><p>Many biomechanical studies have been performed in the last</p><p>years, including in vitro experiments, numerical simulations and</p><p>in vivo investigation (medical imaging) in order to provide a</p><p>better understand of the biomechanical behaviour of cervical</p><p>TDR and give us some responses to the aforementioned ques-</p><p>tions. </p><p>/+/ References.a Ishihara H, Kanamori M, Kawaguchi Y et al. (2004) Adjacent segmentdisease after anterior cervical interbody fusion. Spine J 4: 624-8</p><p>z Dmitriev AE, Cunningham BW, Hu N et al. (2005) Adjacent levelintradiscal pressure and segmental kinematics following a cervical</p><p>total disc arthroplasty: an in vitro human cadaveric model. Spine 30:</p><p>1165-72</p><p>e Barrey C, Campana S, Persohn S et al. (2012) Cervical discprosthesis versus arthrodesis using one-level, hybrid and two-level</p><p>constructs: an in vitro investigation. Eur Spine J 21(3): 432-42</p><p>r Galbusera F, Bellini CM, Brayda-Bruno M, Fornari M (2008)Biomechanical studies on cervical total disc arthroplasty: a literature</p><p>review. Clin Biomech 23: 1095-104</p><p>t Sasso RC, Best NM (2008) Cervical kinematics after fusion and Bryandisc arthroplasty. J Spinal Disord Tech 21: 19-22</p><p>y Rousseau MA, Cottin P, Levante S et al. (2008) In Vivo kinematics oftwo types of ball-and-socket cervical disc replacements in the sagittal</p><p>plane. Cranial versus caudal geometric center. Spine 33:E6-E9</p><p>u Johnson JP, Lauryssen C, Cambron HO et al. (2004) Sagittalalignment and the Bryan cervical artificial disc. Neurosurg Focus 17:</p><p>E4</p><p>i Snyder JT, Tzermiadianos MN, Ghanayem AJ, et al. (2007) Effect ofuncovertebral joint excision on the motion response of the cervical</p><p>spine after total disc replacement. Spine 32: 2965-9</p><p>o Barrey C, Champain S, Campana S, et al. (2012) Sagittal alignmentand kinematics at instrumented and adjacent levels after total disc</p><p>replacement in the cervical spine. Eur Spine J 21(8):1648-59</p><p>/+/ AboutCdric Barrey</p><p>Neurosurgery-Spinal Surgery</p><p>Hospital P. Wertheimer</p><p>59 boulevard Pinel</p><p>69394 Lyon, France</p><p>Dr. Barrey performed his residency at University Claude Bernard in</p><p>Lyon, France and is currently senior assistant professor in the</p><p>Department of Spine Surgery, Prof. G. Perrin, P Wertheimer Hospital</p><p>in Lyon since 2004 (around 400 spine surgeries each year). He spent</p><p>6 months fellowship in the department of Prof. B. George, at Lariboisire</p><p>Hospital, Paris, to get used with Vertebral Artery Surgery and also 6</p><p>other months in the unit of Dr. P. Roussouly who is specialized in the</p><p>management of Spinal Deformities in Lyon. His Research Activities are</p><p>dedicated to: cervical posterior stabilization, spino-pelvic alignment</p><p>and sagittal balance, lumbar dynamic devices and cervical disc pros-</p><p>thesis. In 2008, he was a research fellow at Thomas Jefferson University,</p><p>Department of Spine Surgery, Prof. AR Vaccaro, Philadelphia (USA).</p><p>He performed a biomechanical PhD thesis on cervical disc prosthesis</p><p>in 2011 in collaboration with the Laboratory of biomechanics, Arts et</p><p>Metiers-PARISTECH, Paris, with Prof. W. Skalli as programme director.</p><p>Main Spine Society affiliations: SFNC, SNCLF, ArgoSpine, SFCR,</p><p>AO-SPINE and SSE.</p><p>LECTURE Day 1/ 9:20&gt;9:30</p><p>Dynamic fixation of the cervical spine</p><p>Dynamic Cervical Implant (DCI).Indications and resultsGuy MatgNational Neurosurgical Department, Centre Hospitalier de Luxembourg, Luxembourg</p><p>Although cervical arthroplasty with total disc replacement (TDR)</p><p>has shown equivalence or superiority over anterior cervical dis-</p><p>cectomy and fusion (ACDF) in cervical disc disease, potential</p><p>problems include: non-physiologic motion which may accelerate</p><p>degeneration of the facet joints, particulate wear, and compro-</p><p>mise of the endplate mechanical integrity during device fixation.</p><p>Dynamic cervical stabilization with DCI is a novel motion-pre-</p><p>serving concept that facilitates controlled, limited flexion and</p><p>extension, but prevents axial rotation and lateral bending, thereby</p><p>reducing motion across the facet joints. Consequently, DCI may</p><p>provide the benefit of motion-preservation and reduced risk for</p><p>adjacent segment degeneration, while providing a surgical alter-</p><p>native to patients with facet arthrosis who would otherwise be</p><p>contra-indicated to receiving TDR. The purpose of the current</p><p>study is to report the safety and initial clinical and radiographic</p><p>results of the DCI in the treatment of 1 to 3-level cervical disc</p><p>disease at a single institution.</p><p>Prospective evaluation of 50 consecutive patients (26 females</p><p>and 24 males) with an average age of 50 years (range: 25-79)</p><p>who underwent dynamic cervical stabilization using the 2nd</p><p>generation DCI device between 06/2008 and 12/2010 at a single</p><p>institution for the treatment of one-...</p></li></ul>

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