摘要
第一部分新型经椎弓根螺钉动力内固定系统的研制及对失稳腰椎的稳定性效果测试和对相邻节段的作用
目的：设计出一种新型经椎弓根螺钉动力内固定系统,并测试其对失稳腰椎的稳定性效果及对相邻节段的作用。方法：1、采用6具人新鲜尸体腰椎标本,测试各个节段的活动度,为新型动力内固定系统的设计提供参数支持。2、以钛合金棒、钛缆和钛合金碟片弹簧为主要结构,根据正常腰椎各节段的活动度,参照文献报道的相关测试结果,设定动态连接棒屈曲范围0-10度,旋转范围0-5度,并对其进行了相关力学测试。3、采用6具人新鲜尸体腰椎标本,制作腰椎失稳模型。测试新型动力内固定系统固定后失稳腰椎固定节段及相邻节段的运动范围(ROM)和中性区(NZ),并与坚强固定对比,同时测定其上邻节段软骨终板下压力,探讨其稳定性及对相邻节段的作用。结果：新型动力内固定系统可操作性强,具有良好的抗疲劳、抗拉、抗压及抗扭转性能,坚固耐用,可以提供足够的后路支撑及一定范围内的动态活动范围。新型动力内固定系统和坚强内固定系统固定以后,固定节段三个主方向的ROM和NZ均明显小于失稳模型,差异有显著性意义(P<0.01)。与完整脊柱相比,新型动力内固定系统固定后屈伸和侧屈方向的ROM和NZ较完整脊柱减小(P<0.05),但旋转方向的ROM和NZ与完整脊柱无显著性差异(P>0.05)。与坚强固定组相比,新型动力内固定组三个主方向的ROM和NZ均显著增加,差异有显著性意义(P<0.01)。对于相邻节段,新型动力内固定和坚强内固定的ROM均稍大于完整脊柱,但各组之间并无显著性差异(P＞0.05)。对于L2下软骨终板下压力,各组之间并无显著性差异(P>0.05)。疲劳试验后的结果表明,固定节段在三个主方向上的ROM和NZ均较疲劳前显著增加(P<0.05),但与失稳脊柱相比,差异仍具有显著性意义,与完整脊柱相比,动力内固定屈伸方向的ROM和NZ仍较小,两组相比差异显著(P<0.05),侧屈与旋转方向的ROM和NZ与完整脊柱无显著性差异(P>0.05)。结论：新型动力内固定系统可控性强、可靠性好、能够提供足够的活动度。新型动力内固定系统能对失稳腰椎提供各方向上的稳定性,尤其对前屈后伸的稳定效果最好,疲劳试验后也能提供足够的稳定性。相邻节段的ROM和上邻节段终板下压力与固定方式无显著相关。
第二部分新型动力内固定系统联合经伤椎椎弓根椎体内植骨治疗胸腰推爆裂骨折的生物力学及相关临床研究
目的：观察经伤椎椎弓根椎体内植骨结合椎弓根螺钉坚强内固定术后损伤椎间盘的最终转归情况。测试新型动力内固定系统联合经伤椎椎弓根椎体内植骨的稳定性效果。方法：1、随机选取了25例胸腰椎爆裂骨折病例,所有患者均接受了经伤椎椎弓根椎体内植骨结合短节段椎弓根螺钉内固定手术。观察指标包括X线平片、CT扫描及MRI检查、椎间盘的退变程度、椎体楔变角、脊柱后凸角。2、选取人新鲜尸体胸腰椎标本制作了L2椎体爆裂骨折的模型,测试新型动力内固定系统联合经伤椎椎弓根椎体内植骨的稳定性效果。结果：1、21例患者得到随访,其中男性15例,女性6例。合并椎间盘损伤14例。平均随访时间50.8月(25-91个月)。两组患者椎体楔变角的差异无显著性意义。在脊柱后凸角的改变方面,两组的差异有显著性意义(P<0.05)。两组患者椎间盘退变的比率差异有显著性意义(P<0.01)。2、动力内固定联合经伤椎椎弓根椎体内植骨与骨折状态相比,屈伸及侧屈方向的ROM均显著减小,差异有显著性意义(P<0.01),旋转方向的ROM虽也显著减小(P<0.01),但明显大于完整状态,差异有显著性意义(P<0.01)。结论：1、损伤的椎间盘更容易发生退变,胸腰椎爆裂骨折合并椎间盘损伤在治疗时需注意对损伤椎间盘的处理,临床治疗迫切需要一种既能促进骨折愈合,又能保留运动节段,最大限度恢复脊柱运动功能的新方法。2、新型动力内固定系统联合经伤椎椎弓根椎体内植骨能够维持胸腰椎爆裂骨折在屈伸及侧屈方向的稳定性,但在旋转方向上不足以提供足够的稳定性。需要进一步改进,并增加其旋转稳定性。
Part I Prospective design and stability evaluation of a new dynamic stabilization system in lumbar spine and the effects on adjacent segments
Objective:To design and determine the magnitude of stabilization and the effect on the adjacent segment of a new dynamic stabilization system. Methods:1. Six lumbar cadaver spines were tested for ROM of each segment.2. New dynamic system consists of titanium-alloy rods, cables and springs. The system was designed for 10°motion in flextion-extension and lateral bending,5°for rotation. 3. Six lumbar cadaver spines were used for testing. A controlled defect was created in the L3-4 segment. The ROM for the bridged and the adjacent segments were determined. The end plate stress of both stabilization methods on the superior adjacent segments were measured at the same time. Results:Both the dynamic system and rigid fixator reduced the ROM and NZ below the magnitude of the intact spine for lateral bending, flexion and extension. In axial rotation the ROM for the dynamic system was in the range of the intact spine, while the rigid fixator showed a decreased ROM. For adjacent segments, no significant differences of ROM were found among intact, dynamic and rigid fixation systems. Conclusion:In the lumbar cadaver spines after defect was created in the L3-4 segment, restoration of stability with the new dynamic system is possible in flexion, extension, right and left lateral bending, and in axial rotation. The ROM and NZ of the adjacent segments were not affected by the instrumentation of the bridged segment.
Part II Stability evaluation of the new dynamic stabilization system combined with transpedicular intracorporeal bone grafting for thoracolumbar burst fractures and correlated clinical research
Objective:To evaluate the fate of injuried discs for acute thoracolumbar burst fractures. And to determine the magnitude of stabilization of the new dynamic system combined with transpedicular intracorporeal bone grafting. Methods:1. Patients with acute thoracolumbar fractures were randomized selected, who had been operatively treated with short segment posterior instrumentation supplemented with transpedicular intracorporeal bone grafting. A grading system for lumbar disc degeneration was used. The superior-inferior endplate angle and vertebral body angle had been assessed at follow up.2. Six thoracolumbar cadaver spines were used for testing. A controlled L2 burst fracture was created. The L1-3 motions were determined. Reaults:1. For alteration of superior-inferior endplate angle and the degeneration rate of discs, the deference between two groups were significant.2. In extension, flexion and lateral bending, the dynamic fixator stabilized the segment to a ROM below the magnitude of the intact spine, but showed an increased ROM of axial rotation (P< 0.05) compared with the intact spine. Conclusion:1. The injuried discs were liable to degeneration.2. Restoration of stability with the newly developed dynamic system combined with transpedicular intracorporeal bone grafting is possible in flexion, extension, right and left lateral bending for thoracolumbar burst fracture but for axial rotation.
引文
[1]Fritzell P, Hagg O, Wessberg P, et al. Chronic low back pain and fusion:a comparison of three surgical techniques:a prospective multicenter randomized study from the Swedish lumbar spine study group. Spine.2002,27(11): 1131-1141.
[2]Fritzell P, Hagg O, Nordwall A. Complications in lumbar fusion surgery for chronic low back pain:comparison of three surgical techniques used in a prospective randomized study. A report from the Swedish Lumbar Spine Study Group. Eur Spine J.2003,12(2):178-189.
[3]Bono CM, Lee CK. Critical analysis of trends in fusion for degenerative disc disease over the past 20 years:influence of technique on fusion rate and clinical outcome. Spine.2004,29(4):455-463; discussion Z5.
[4]Gibson JN, Waddell G, Gibson JA. Surgery for degenerative lumbar spondylosis. Cochrane Database Syst Rev.2005, (4):CD001352.
[5]Panjabi MM. Hybrid multidirectional test method to evaluate spinal adjacent-level effects. Clin Biomech (Bristol, Avon).2007,22(3):257-265.
[6]Dekutoski MB, Schendel MJ, Ogilvie JW, et al. Comparison of in vivo and in vitro adjacent segment motion after lumbar fusion. Spine.1994; 19(15):1745-1751.
[7]Cheh G, Bridwell KH, Lenke LG, et al. Adjacent segment disease following lumbar/thoracolumbar fusion with pedicle screw instrumentation:a minimum 5-year follow-up. Spine.2007,32(20):2253-2257.
[8]Chou WY, Hsu CJ, Chang WN, et al. Adjacent segment degeneration after lumbar spinal posterolateral fusion with instrumentation in elderly patients. Arch Orthop Trauma Surg.2002,122(1):39-43.
[9]Nockels RP. Dynamic stabilization in the surgical management of painful lumbar spinal disorders. Spine.2005,30(16 Suppl):S68-S72.
[10]Schnake KJ, Schaeren S, Jeanneret B. Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis. Spine.2006,31(4):442-449.
[11]Sengupta DK. Dynamic stabilization devices in the treatment of low back pain. Neurol India.2005,53(4):466-474.
[12]Sengupta DK. Point of view:dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis. Spine.2006,31(4):450.
[13]Sengupta DK. Dynamic stabilization devices in the treatment of low back pain. Orthop Clin North Am.2004,35(1):43-56.
[14]Schmoelz W, Huber JF, Nydegger T, et al. Dynamic stabilization of the lumbar spine and its effects on adjacent segments:an in vitro experiment. J Spinal Disord Tech.2003,16(4):418-423.
[15]Wilke HJ, Heuer F, Schmidt H. Prospective design delineation and subsequent in vitro evaluation of a new posterior dynamic stabilization system. Spine. 2009,34(3):255-261.
[16]Graf H. Lumbar instability. Surgical treatment without fusion. Rachis.1992, 412(4):123-137.
[17]Schmoelz W, Huber JF, Nydegger T, et al. Influence of a dynamic stabilisation system on load bearing of a bridged disc:an in vitro study of intradiscal pressure. Eur Spine J.2006,15(8):1276-1285.
[18]McNally DS. The objectives for mechanical evaluation of spinal instrumentation have changed. Eur Spine J.2002, 11(suppl 2):S179-S185.
[19]郑晓勇,侯树勋,李利,等.胸腰椎爆裂骨折内固定术后伤椎相邻椎间盘及上邻节段椎间盘的转归.中国骨肿瘤骨病.2009,8(6)：346-349.
[20]Wahba GM, Bhatia N, Bui CN, et al. Biomechanical evaluation of short-segment posterior instrumentation with and without crosslinks in a human cadaveric unstable thoracolumbar burst fracture model. Spine.2010, 35(3):278-285.
[21]Wilke HJ, Rohlmann F, Neidlinger-Wilke C, et al. Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration:part Ⅰ. Lumbar spine. Eur Spine J.2006,15(6):720-730.
[22]Heuer F, Schmidt H, Claes L, et al. Stepwise reduction of functional spinal structures increase vertebral translation and intradiscal pressure. J Biomech. 2007,40(4):795-803.
[23]Heuer F, Schmidt H, Klezl Z, et al. Stepwise reduction of functional spinal structures increase range of motion and change lordosis angle. J Biomech. 2007,40(2):271-280.
[24]Plamondon A, Gagnon M, Maurais G. Application of a stereoradiographic method for the study of intervertebral motion. Spine.1988,13(2):1027-1032.
[25]Pearcy M, Portek I, Shepherd J. Three-dimensional X-ray analysis of normal movement in the lumbar spine. Spine.1984,9(l):294-297.
[26]Yamamoto I, Panjabi MM, Crisco T, et al. Three-dimensional movements of the whole lumbar spine and lumbosacral joint. Spine 1989,14(2):1256-1260.
[27]原林,朱青安,王兴海,等.腰骶段脊柱的三维运动范围.中国临床解剖学杂志.1994,12(2)：154-155.
[28]Mulholland RC, Sengupta DK. Rationale, principles and experimental evaluation of the concept of soft stabilization. Eur Spine J.2002, 11(suppl 2):198-205.
[29]Madan S, Boeree NR. Outcome of the Graf ligamentoplasty procedure compared with anterior lumbar interbody fusion with the Hartshill horseshoe cage. Eur Spine J.2003,12(4):361-368.
[30]Grevitt MP, Gardner AD, Spilsbury J, et al. The Graf stabilisation system: early results in 50 patients. Eur Spine J.1995,4(3):169-175.
[31]Hadlow S, Fagan, AB, Glas H, et al. The Graf ligamentoplasty procedure: Comparison with posterolateral fusion in the management of low back pain. Spine.1998,23(10):1172-1179.
[32]Rigby MC, Selmon GPF, Foy MA, Fogg AJB. Graf ligament stabilisation: mid-to long-term follow-up. Eur Spine J.2001,10(3):234-236.
[33]Stoll TM, Dubois G, Schwarzenbach O. The dynamic neutralization system for the spine:A multi-center study of a novel non-fusion system. Eur Spine J. 2002,11(Suppl 2):S170-178.
[34]Grob D, Benini A, Junge A, et al. Clinical experience with the Dynesys semirigid fixation system for the lumbar spine:surgical and patient-oriented outcome in 50 cases after an average of 2 years. Spine.2005,30(3):324-331.
[35]Sengupta D. Prospective clinical trial of soft stabilization with the DSS (Dynamic Stabilization System). Spinal Arthroplasty Society.2005, New York.
[36]Niosi CA, Wilson DC, Zhu Q, et al. The effect of dynamic posterior stabilization on facet joint contact forces:an in vitro investigation. Spine. 2008,33(1):19-26.
[37]Schmoelz W, Huber JF, Nydegger T, et al. Dynamic stabilization of the lumbar spine and its effects on adjacent segments:an in vitro experiment. J Spinal Disord Tech.2003,16(4):418-423.
[38]Zander T, Rohlmann A, Burra NK, et al. Effect of a posterior dynamic implant adjacent to a rigid spinal fixator. Clin Biomech (Bristol,-Avon).2006, 21(8):767-774.
[39]Wilke HJ, Kavanagh S, Neller S, et al. Effect of a prosthetic disc nucleus on the mobility and disc height of the L4-5 intervertebral disc postnucleotomy. J Neurosurg.2001,95 (suppl 2):208-214.
[40]Quint U, Wilke HJ, Loer F, et al. Possibilities for static and dynamic stabilization of the spine in lesions of the anterior and posterior ligament complex. Unfallchirurg.1998,101(9):684-690.
[41]Rohlmann A, Neller S, Bergmann G, et al. The effect of an internal fixator and a bone graft on intersegmental spinal motion and intradiscal pressure in the adjacent regions. Eur Spine J.2001,10(3):301-308.
[42]Rohlmann A, Calisse J, Bergmann G, et al. Internal spinal fixator stiffness has only a minor influence on stresses in the adjacent discs. Spine.1999, 24(12):1192-1195.
[43]Lin RM, Panjabi MM, Oxland TR. Functional radiographs of acute thoracolumbar burst fractures:a biomechanical study. Spine.1993,18(16): 2431-2437.
[44]Cunningham BW, Yoshihisa K, McNulty PS, et al. The effect of spinal destabilisation and instrumentation on lumbar intradiscal pressure:An in-vitro biomechanical analysis. Spine.1997,22 (22):2655-2663.
[45]Pfirrmann CW, Metzdorf A, Zanetti M, etal. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine.2001,26(17): 1873-1878.
[46]Oner FC, van der Rijt RR, Ramos LM, et al. Changes in the disc space after fractures of the thoracolumbar spine. J Bone Joint Surg (Br).1998, 80(5):833-839.
[47]Ruey Molin, Manohar M. Functional radiographs of acute thoracolumbar burst fractures. Spine.1993,18(16):2431-2437.
[48]Oner FC, van der Rijt RH. Correlation of MR images of disc injuries with anatomic sections in experimental thoracolumbar spine fractures. Eur Spine J. 1999,8(3):194-198.
[49]McLain RF, Sparling E, Benson DR. Early failure of short-segment pedicle instrumentation for thoracolumbar fractures. A preliminary report. J Bone Joint Surg (Am).1993,75(2):162-167.
[50]Walchli B, Heini P, Berlemann U. Loss of correction after dorsal stabilization of burst fractures of the thoracolumbar junction:The role of transpedicular spongiosa plasty [in German]. Unfallchirurg.2001,104(8):742-747.
[51]Ebelke DK, Asher MA, Neff JR, et al. Survivorship analysis of VSP spine instrumentation in the treatment of thoracolumbar and lumbar burst fractures. Spine.1991,16(8 Suppl):S428-432.
[52]Daniaux H, Seykora P, Genelin A, et al. Application of posterior plating and modifications in thoracolumbar spine injuries:Indication, techniques, and results. Spine.1991,16(3 Suppl):S125-S133.
[53]Alanay A, Acaroglu E, Yazici M, et al. The effect of transpedicular intracorporeal grafting in the treatment of thoracolumbar burst fractures on canal remodeling. Eur Spine J.2001,10(6):512-516.
[54]Knop C, Fabian HF, Bastian L, et al. Late results of thoracolumbar fractures after posterior instrumentation and transpedicular bone grafting. Spine.2001, 26(1):88-99.
[55]Stephens GC, Devito DP, McNamara MJ. Segmental fixation of lumbar burst fractures with Cotrel-Dubousset instrumentation. J Spinal Disord.1992, 5(3):344-348.
[56]Gurwitz GS, Dawson J, McNamara MJ, et al. Biomechanical analysis of three surgical approaches for lumbar burst fractures using short segment instrumentation. Spine.1993,18(1):977-82.
[57]Kramer Dl, Rodgers WB, Mansfield FL. Transpedicular instrumentation and short-segment fusion of thoracolumbar fractures:a prospective study using a single instrumentation system. J Orthop Trauma.1995,9(6):499-506.
[58]McCormack T, Kariokovic E, Gaines RW. The load sharing classification of spine fractures. Spine.1994,19(15):1741-1744.
[59]Muller U, Berlemann U, Sledge J, et al. Treatment of thoracolumbar burst fractures without neurologic deficit by indirect reduction and posterior instrumentation:bisegmental stabilization with monosegmental fusion. Eur Spine J.1999,8(4):284-289.
[60]Handa T, Ishihara H, Ohshima H, et al. Effects of Hydrostatic pressure on matric synthesis and matrix metalloproteinase production in the human lumbar intervertebral disc. Spine.1997,22(10):1085-1091.
[61]Holm S, Nachemson A. Nutritional changes in the canine intervertebral disc after spinal fusion. Clin Orthop.1982,169(4):243-258.
[62]Maclean J, Lee C, Grad S, et al. Effects of immobilization and dynamic compression on intervertebral disc cell gene expression in vivo. Spine.2003, 28(10):973-981.
[63]Daniaux H. Transpedikulare reposition und spongiosaplastik bei wirbelbruchen der unteren burst-und lendenwirbelsaule. Unfallchirurg.1986, 89(3):197-213.
[64]Aebi M, Etter C, Kehl T, et al. Stabilization of the lower thoracic and lumbar spine with the internal spinal skeletal fixation system:indications, techniques, and first results of treatment. Spine.1987,12(1):544-551.
[65]Alvine GF, Swain JM, Asher MA. The safety and efficacy of variable screw placement (VSP) and Isola spinal implant systems for the surgical treatment of thoracolumbar burst fractures [abstract]. J Bone Joint Surg [Br].1997,79 (suppl):306.
[66]Bernucci C, Maiello M, Silvestro C, et al. Delayed worsening of the surgical correction of angular and axial deformity consequent to burst fractures of the thoracolumbar or lumbar spine. Surg Neurol.1994,42(3):23-52.
[67]Crawford RJ, Askin GN. Fixation of thoracolumbar fractures with the Dick fixator:the influence of transpedicular bone grafting. Eur Spine J.1994,3(1): 45-51.
[68]Knop C, Blauth M, Bastian L, et al. Fracturen der thorakolumbalen Wirbelsaule:Spatergebnisse nach dorsaler Instrumentierung und ihre Konsequenzen. Unfallchirurg.1997,100(2):630-639.
[69]Olerud S, Karlstrom G, Sjostrom L. Transpedicular fixation of thoracolumbar vertebral fractures. Clin Orthop.1998,227(3):44-51.
[70]Speth MJ, Oner FC, Kadic MA, et al. Recurrent kyphosis after posterior stabilization of thoracolumbar fractures:24 cases treated with a Dick internal fixator followed for 1.5-4 years. Acta Orthop Scand.1995,66(5):406-410.
[71]Stromsoe K. Unstable spinal injuries:Guidelines for treatment. Tidsskr Nor Laegeforen.1992,10(112):1282-1286.
[72]Wavro W, Konrad L, Aebi M. Die monosegmentale montage des fixateur interne bei der behandlung von thorakolumbalen wirbelfrakturen. Unfallchirurg.1994,97(7):114-120.
[73]Wilcox RK, Allen DJ, Hall RM, et al. A dynamic investigation of the burst fracture process using a combined experimental and finite element approach. Eur Spine J.2004,13(1):481-488.
[74]Panjabi MM, Hoffman H, Kato Y, et al. Superiority of incremental trauma apporoach in experimental burst fracture studies. Clin Biomech.2000, 15(2):73-78.
[75]Lim TH, Eck JC, An HS, et al. Biomechanics of transfixation in pedicle screw instrumentation. Spine.1996,21(12):2224-2229.
[76]Brodke DS, Bachus KN, Mohr RA, et al. Segmental pedicle screw fixation or cross-links in multilevel lumbar constructs. A biomechanical analysis. Spine. 2001,1(5):373-379.
[77]Valdevit A, Kambic HE, Mclain RF. Torsional stability of cross-link configurations:a biomechanical analysis. Spine.2005,5(9):441-445.
[78]Lynn G, Mukherjee DP, Kruse RN, et al. Mechanical stability of thoracolumbar pedicle screw fixation. The effect of crosslinks. Spine. 1997,22(14):1568-1572.
[1]Fritzell P, Hagg O, Wessberg P, et al. Chronic low back pain and fusion:a comparison of three surgical techniques:a prospective multicenter randomized study from the Swedish lumbar spine study group. Spine.2002,27(11): 1131-1141.
[2]Fritzell P, Hagg O, Nordwall A. Complications in lumbar fusion surgery for chronic low back pain:comparison of three surgical techniques used in a prospective randomized study. A report from the Swedish Lumbar Spine Study Group. Eur Spine J.2003,12(2):178-189.
[3]Highsmith JM, Tumialan LM, Rodts GE. Flexible rods and the case for dynamic stabilization. Neurosurg Focus.2007,22(1):E11.
[4]Sengupta DK. Dynamic stabilization devices in the treatment of low back pain. Orthop Clin North Am.2004,35(1):43-56.
[5]Graf H. Lumbar instability. Surgical treatment without fusion. Rachis.1992, 412(4):123-137.
[6]Schnake KJ, Schaeren S, Jeanneret B. Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis. Spine.2006,31(4):442-449.
[7]Stoll TM, Gilles Dubois G, Schwarzenbach O. The dynamic neutralization system for the spine:A multi-center study of a novel non-fusion system. Eur Spine J.2002, 11(Suppl 2):S170-178.
[8]Grob D, Benini A, Junge A, et al. Clinical experience with the Dynesys semirigid fixation system for the lumbar spine:surgical and patient-oriented outcome in 50 cases after an average of 2 years. Spine.2005,30(3):324-331.
[9]Sengupta D. Prospective clinical trial of soft stabilization with the DSS (Dynamic Stabilization System). Spinal Arthroplasty Society. May,2005, New York.
[10]Sengupta DK, Mulholland RC. Fulcrum assisted soft stabilization system:a new concept in the surgical treatment of degenerative low back pain. Spine. 2005,30(9):1019-1029.
[11]Yue JJ, Timm JP, Panjabi MM, et al. Clinical application of the Panjabi neutral zone hypothesis:the Stabilimax NZ posterior lumbar dynamic stabilization system. Neurosurg Focus.2007,22(1):E12.
[12]Mandigo CE, Sampath P, Kaiser MG. Posterior dynamic stabilization of the lumbar spine:pedicle based stabilization with the AccuFlex rod system. Neurosurg Focus.2007,22(1):E9.
[13]Niosi CA, Wilson DC, Zhu Q, et al. The effect of dynamic posterior stabilization on facet joint contact forces:an in vitro investigation. Spine.2008, 33(1):19-26.
[14]Schmoelz W, Huber JF, Nydegger T, et al. Dynamic stabilization of the lumbar spine and its effects on adjacent segments:an in vitro experiment. J Spinal Disord Tech.2003,16(4):418-423.
[15]Schmoelz W, Huber JF, Nydegger T, et al. Influence of a dynamic stabilisation system on load bearing of a bridged disc:an in vitro study of intradiscal pressure. Eur Spine J.2006,15(8):1276-1285.
[16]Zander T, Rohlmann A, Burra NK, et al. Effect of a posterior dynamic implant adjacent to a rigid spinal fixator. Clin Biomech (Bristol,-Avon).2006, 21(8):767-774.
[17]Rohlmann A, Burra NK, Zander T. Comparison of the effects of bilateral posterior dynamic and rigid fixation devices on the loads in the lumbar spine:a finite element analysis. Eur Spine J.2007,16(8):1223-1231.
[18]Cheng BC, Gordon J, Cheng J. Immediate biomechanical effects of lumbar posterior dynamic stabilization above a circumferential fusion. Spine.2007, 32(23):2551-2557.
[19]Schwarzenbach O, Launer R, Els M. Dynamic Neutralization with DYNESYS for the treatment of degenerative Spine disease. Eur Spine J.2001, 10(suppl):S57.
[20]Sapkas GS, Themistocleous GS, Mavrogenis AF, et al. Stabilization of the lumbar spine using the dynamic neutralization system. Orthopedics.2007, 30(1):859.
[21]Bordes-Monmeneu M, Bordes-Garcia V, Rodrigo-Baeza F, et al. System of dynamic neutralization in the lumbar spine:experience on 94 cases. Neurocirugia (Astur).2005,16(1):499-506.
[22]Welch WC, Cheng BC. Awad TE, et al. Clinical outcomes of the Dynesys dynamic neutralization system:1-year preliminary results. Neurosurg Focus. 2007,22(1):E8.
[23]Cakir B, Ulmar B, Koepp H, et al. Posterior dynamic stabilization as an alternative for dorso-ventral fusion in spinal stenosis with degenerative instability [in German]. Z Orthop Ihre Grenzgeb.2003,141(4):418-424.
[24]Putzier M, Schneider SV, Funk JF, et al. The surgical treatment of the lumbar disc prolapse:nucleotomy with additional transpedicular dynamic stabilization versus nucleotomy alone. Spine.2005,30(2):E109-E114.
[25]Soo-Eon Lee, Sung-Bae Park, Tae-Ahn Jahng, et al. Clinical experience of the dynamic stabilization system for the degenerative spine disease. J Korean Neurosurg Soc.2008,43(3):221-226.
[26]Schaeren S, Broger I, Jeanneret B. Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization. Spine.2008,33(18):E636-642.
[27]Bothmann M, Kast E, Boldt GJ, et al. Dynesys fixation for lumbar spine degeneration. Neurosurg Rev.2008,31(2):189-196.
[28]Kanayama M, Hashimoto T, Shigenobu K, et al. Nonfusion surgery for degenerative spondylolisthesis using artificial ligament stabilization:surgical indication and clinical results. Spine.2005,30(5):588-592.
[29]Kanayama M, Hashimoto T, Shigenobu K, et al. A minimum 10-year follow-up of posterior dynamic stabilization using Graf artificial ligament. Spine.2007,32(18):1992-6; discussion 1997.
[30]Rigby MC, Selmon GP, Foy MA, et al. Graf ligament stabilisation:mid to long term follow-up. Eur Spine J.2001,10(3):234-236.
[31]Schwarzenbach O, Berleman U, Stoll TM et al. Posterior dynamic stabilization systems:DYNESYS. Orthop Clin North Am.2005, 36(3):363-372.