中文摘要
目的:
發展Dynesy動態脊椎內固定器的目的是為了克服傳統腰椎融合手術所造成的鄰近節段問題，但是對於處理多節段的腰椎問題時，使用固定手術或者非固定手術目前還是未定論。 這篇研究有兩個目的1.臨床研究上,結合固定手術與非固定手術(Hybrid surgery)去處理多節段腰椎的問題，評估手術後功能改善的情況以及手術後力學上的變化。2.基礎研究部分, 評估影響Dynesys的因子
臨床研究
方法及材料
實驗共收集28個病人，包括10個男性及18個女性，年紀範圍從40歲到75歲(平均年齡為60 歲)。這些病人同時存在兩個節段腰椎的問題，在神經減壓後對於嚴重退化以及不穩定的節段行融合手術(Fusion surgery)，對於輕微退化或者無不穩定的節段行非固定手術(Non-fusion surgery)。針對手術前後病人的功能改善情況以及力學上的變化做評估，追蹤期間從24個月到37個月(平均追蹤期間為32.7個月)。
結果
手術後功能(Functional outcome)及疼痛(VAS)有明顯統計上的改善，手術後活動度改變(1)在橋段(bridged segment)活動度沒有明顯改變、(2)融合節段(Fused segment)有高的融合的比率、(3)但是在鄰近節段(Adjacent segment)發現會增加活動度。
基礎研究
方法及材料
總共使用八隻羊第四五節腰椎。實驗共分成五種不同固定型態，第一種未植入任何固定器完整組(Intact)，第二種以標準方式組裝後側動態穩定系統(Dynesys)，以自然長度的 Spacer (neutral length)及300N張力的索(cord)組裝(Dynesys with neutral length of spcaer and 300N pretension of cord)，第三種以非標準方式組裝後側動態穩定系統(Dynesys)，以自然長度的的 Spacer(neutral length)及無張力的索(cord)(Dynesys with neutral length of spcaer and 0N pretension of cord)，第四種以非標準方式組裝後側動態穩定系統(Dynesys)，300N張力的索(cord)沒有使用Spacer組裝(Dynesys without spacer and 300N pretension of cord)，第五種植入金屬固定器(rigid rod fixation)。將五種不同固定型態裝置於脊椎測試器(spinal tester)上針對於三個主要動作的活動度(ROM)及 中立區(Neutral zone)做資料收集併分析。
結果
測試結果發現在前彎後彎( flexion- extension)及側彎(lateral bending)植入後側動態穩定系統(Dynesys)及僵硬固定器( Rigid rod fixation))比起未植入任何固定器的完整組(intact)活動度及中立區(neutral zone)皆增加，並且發現增加增加索張力(cord pretension)會造成前彎後彎(flexion- extension)的活動度及中立區下降。
結論
臨床的結果發現，後側動態穩定系統結合融合手術(Dynesys stabilization with interbody fusion)是可改善臨床的結果，並且達到椎體融合手術的目的，並且可以保留橋段的活動度。但是對會限制整體的活動，所以後續研究主要會著眼於決定適當的spacer長度、以及索張力的研究。
在基礎研究發現，後側動態穩定系統的力學變化與僵硬固定器類似，索張力(cord pretension)增加會造成活動度下降，雖然我們知道決定spacer的長度以及索張力(pretension of cord)是重要的開刀的決策但是有賴後續的臨床及基礎的研究。

Abstract
Purpose
Traditionally, surgeons manage the multilevel lumbar degenerative disc disease either with fusion or nonfusion surgery alone. Multilevel lumbar degenerative disc disease exists vary in extent of degeneration and instability. It seems reasonable using various surgical techniques in one stage surgery either fusion, non-fusion or hybrid technique in multilevel lumbar degenerative disc disease. Hybrid segment-by-segment with Dynesys in combination with interbody fusion is an alternative method for multilevel degenerative lumbar disc disease. Little was reported about the hybrid stabilization. To the best of our knowledge, no kinematic study has been reported for the Dynesys fusion-nonfusion technique. In clinical study, we report the clinical outcome and the kinematic change in bridged and adjacent segment after hybrid stabilization with interbody fusion. In vitro study, we investigate how the tension of cord and length of spacer in posterior dynamic stabilization affects the three-dimensional flexibility in sheep lumbar spine.
In clinical study
--Posterior Dynamic neutralization stabilization system (Dynesys) with interbody fusion in patients with two-segment lumbar degenerative disc disease--
Materials and Methods
Twenty-eight patients who underwent posterior lumbar interbody fusion with posterior dynamic stabilization fixation for spondylolisthesis with adjacent level stenosis between May 2007 and June 2008 and could be followed for at least 2 years were included in this study. All patients’ clinical characteristics had been reviewed retrospectively. These 28 patients consisted of 10 males and 18 females, with ages ranging from 40 to 75 years (with a mean age of 60). The mean follow-up time is 32.7 months (range, 24 to 37). The visual analog scale (VAS) was used to score both lower-limb and back pain. Patient functioning was evaluated using the Oswestry Disability Index (ODI).
Results
Both VAS and ODI significantly improved during the follow-up period (p<0.001). The preoperative back and leg VAS score was 7.48±1.35 and 7.59±0.82, respectively, whereas the postoperative back and leg VAS score was 2.00±1.07 and 1.52±0.57. Respectively, ODI was 52.1±3.1%, whereas the postoperative ODI was 11.1±5.6%. The global motion was decreased significantly after surgery (p=0.027). In adjacent segment motion, neutral lordotic curve was created significantly (p<0.001) and range of motion was hypermobility significantly (p<0.001) after surgery. In bridged segment, the motion was no significant different between before and after surgery.
In vitro study
-- The effects of tension of cord and the spacer in dynamic neutralization stabilization system (Dynesys)—
Material and methods
For this in-vitro trial, eight motion segments of L4/5 from sheep lumbar spines were studied. Each specimen in the intact state, Dynesys with neutral spacer and 300N pretension of cord, Dynesys with neutral spacer and no pretension of cord, Dynesys with 300N without spacer, and rigid rod fixation were evaluated in sequence. A compressive preload of 50 N was applied. The direction was reversed until the moment detected by the load cell applied 4Nm in all specimens. The range of motion (ROM) and neutral zone (NZ) of flexion-extension, lateral bending and axial rotation were measured calculated to evaluate the flexibility of sheep lumbar spine in different surgical conditions.
Results
Comparing to the intact specimen, the range of motion (ROM) of flexion-extension and lateral bending were significantly reduced following both different instrumentation with dynamic stabilization implants and rigid fixator (p<0.001). The range of motion in flexion-extension was significantly reduced when increased the pretension of cord (p=0.013).
Conclusions
Dynesys stabilization with interbody fusion can improve clinical outcome, achieve successful interbody fusion, and maintain the ROM in the bridged segment. However, it may decrease the ROM in the global segment and produce hypermobility in the adjacent segment. In further work, determining the precise length of spacer and tension of cord are necessary whatever in vivo or in vitro experiments.
On the basis of this in vitro study, the kinematic behavior of Dynesys is similar to the rigid rod fixation. The flexibility of Dynesys was reduced by increasing the tension of cord. The tension of cord plays the key role of flexibility of Dynesys than the length of spacer. Although determining the tension of cord and length of spacer is the curial surgical options, the role of tension of cord and the length of spacer need further in vitro or in vivo study.

1.Lee, C.K. and N.A. Langrana, Lumbosacral spinal fusion. A biomechanical study. Spine (Phila Pa 1976), 1984. 9(6): p. 574-81.
2.Eck, J.C., S.C. Humphreys, and S.D. Hodges, Adjacent-segment degeneration after lumbar fusion: a review of clinical, biomechanical, and radiologic studies. Am J Orthop (Belle Mead NJ), 1999. 28(6): p. 336-40.
3.Ekman, P., et al., A prospective randomised study on the longterm effect of lumbar fusion on adjacent disc degeneration. Eur Spine J, 2009. 18(8): p. 1175-86.
4.Li, C.D., et al., [Influence factors of adjacent segment degeneration after instrumented lumbar fusion]. Zhonghua Wai Ke Za Zhi, 2006. 44(4): p. 246-8.
5.Yang, J.Y., J.K. Lee, and H.S. Song, The impact of adjacent segment degeneration on the clinical outcome after lumbar spinal fusion. Spine (Phila Pa 1976), 2008. 33(5): p. 503-7.
6.Liu, Z.Z., Z.M. Zhang, and D.D. Jin, [Factors affecting adjacent segment degeneration after rigid lumbar internal fixation]. Nan Fang Yi Ke Da Xue Xue Bao, 2010. 30(5): p. 1134-7.
7.Rahm, M.D. and B.B. Hall, Adjacent-segment degeneration after lumbar fusion with instrumentation: a retrospective study. J Spinal Disord, 1996. 9(5): p. 392-400.
8.Cheh, G., et al., Adjacent segment disease followinglumbar/thoracolumbar fusion with pedicle screw instrumentation: a minimum 5-year follow-up. Spine (Phila Pa 1976), 2007. 32(20): p. 2253-7.
9.Hayashi, T., et al., Degenerative change in the adjacent segments to the fusion site after posterolateral lumbar fusion with pedicle screw instrumentation--a minimum 4-year follow-up. Fukuoka Igaku Zasshi, 2008. 99(5): p. 107-13.
10.Lee, C.S., et al., Risk factors for adjacent segment disease after lumbar fusion. Eur Spine J, 2009. 18(11): p. 1637-43.
11.Aiki, H., et al., Adjacent segment stenosis after lumbar fusion requiring second operation. J Orthop Sci, 2005. 10(5): p. 490-5.
12.Cho, K.S., et al., Risk factors and surgical treatment for symptomatic adjacent segment degeneration after lumbar spine fusion. J Korean Neurosurg Soc, 2009. 46(5): p. 425-30.
13.Zencica, P., et al., [Adjacent segment degeneration after lumbosacral fusion in spondylolisthesis: a retrospective radiological and clinical analysis]. Acta Chir Orthop Traumatol Cech, 2010. 77(2): p. 124-30.
14.Ghiselli, G., et al., Adjacent segment degeneration in the lumbar spine. J Bone Joint Surg Am, 2004. 86-A(7): p. 1497-503.
15.Resnick, D.K. and W.C. Watters, Lumbar disc arthroplasty: a critical review. Clin Neurosurg, 2007. 54: p. 83-7.
16.Gamradt, S.C. and J.C. Wang, Lumbar disc arthroplasty. Spine J, 2005. 5(1): p. 95-103.
17.Frelinghuysen, P., et al., Lumbar total disc replacement part I: rationale, biomechanics, and implant types. Orthop Clin North Am, 2005. 36(3): p. 293-9.
18.Khoueir, P., K.A. Kim, and M.Y. Wang, Classification of posterior dynamic stabilization devices. Neurosurg Focus, 2007. 22(1): p. E3.
19.Dubois G, d.G.B., Schaerer NS et al, Dynamic neutralization: a new concept for restabilization of the spine. In: Spzalski M, Gunzburg R, Pope MH, eds. Lumbar Segmental Instability. Philadelphia, PA, 1999: p. 233-240.
20.Freudiger, S., G. Dubois, and M. Lorrain, Dynamic neutralisation of the lumbar spine confirmed on a new lumbar spine simulator in vitro. Arch Orthop Trauma Surg, 1999. 119(3-4): p. 127-32.
21.Mulholland, R.C. and D.K. Sengupta, Rationale, principles and experimental evaluation of the concept of soft stabilization. Eur Spine J, 2002. 11 Suppl 2: p. S198-205.
22.Kumar, A., et al., Disc changes in the bridged and adjacent segments after Dynesys dynamic stabilization system after two years. Spine (Phila Pa 1976), 2008. 33(26): p. 2909-14.
23.Schmoelz, W., 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): p. 418-23.
24.Grob, D., 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 (Phila Pa 1976), 2005. 30(3): p. 324-31.
25.Putzier, M., et al., The surgical treatment of the lumbar disc prolapse: nucleotomy with additional transpedicular dynamic stabilization versus nucleotomy alone. Spine (Phila Pa 1976), 2005. 30(5): p. E109-14.
26.Bordes-Monmeneu, M., et al., [System of dynamic neutralization in the lumbar spine: experience on 94 cases.]. Neurocirugia (Astur), 2005. 16(6): p. 499-506.
27.Schnake, K.J., S. Schaeren, and B. Jeanneret, Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis. Spine (Phila Pa 1976), 2006. 31(4): p. 442-9.
28.Welch, W.C., et al., Clinical outcomes of the Dynesys dynamic neutralization system: 1-year preliminary results. Neurosurg Focus, 2007. 22(1): p. E8.
29.Bothmann, M., et al., Dynesys fixation for lumbar spine degeneration. Neurosurg Rev, 2008. 31(2): p. 189-96.
30.Wurgler-Hauri, C.C., et al., Dynamic neutralization of the lumbar spine after microsurgical decompression in acquired lumbar spinal stenosis and segmental instability. Spine (Phila Pa 1976), 2008. 33(3): p. E66-72.
31.Schaeren, S., I. Broger, and B. Jeanneret, Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization. Spine (Phila Pa 1976), 2008. 33(18): p. E636-42.
32.Ricart, O. and J.M. Serwier, [Dynamic stabilisation and compression without fusion using Dynesys for the treatment of degenerative lumbar spondylolisthesis: a prospective series of 25 cases]. Rev Chir Orthop Reparatrice Appar Mot, 2008. 94(7): p. 619-27.
33.Lee, S.E., et al., Clinical experience of the dynamic stabilization system for the degenerative spine disease. J Korean Neurosurg Soc, 2008. 43(5): p. 221-6.
34.Di Silvestre, M., et al., Dynamic stabilization for degenerative lumbar scoliosis in elderly patients. Spine (Phila Pa 1976), 2010. 35(2): p. 227-34.
35.Schwarzenbach, O., N. Rohrbach, and U. Berlemann, Segment-by-segment stabilization for degenerative disc disease: a hybrid technique. Eur Spine J, 2010. 19(6): p. 1010-20.
36.Cienciala, J., et al., [Dynamic Neutralization Using the Dynesys System for Treatment of Degenerative Disc Disease of the Lumbar Spine.]. Acta Chir Orthop Traumatol Cech, 2010. 77(4): p. 203-208.
37.Ko, C.C., et al., Screw loosening in the Dynesys stabilization system: radiographic evidence and effect on outcomes. Neurosurg Focus, 2010. 28(6): p. E10.
38.Delank, K.S., et al., How does spinal canal decompression and dorsal stabilization affect segmental mobility? A biomechanical study. Arch Orthop Trauma Surg, 2010. 130(2): p. 285-92.
39.Gedet, P., et al., Comparative biomechanical investigation of a modular dynamic lumbar stabilization system and the Dynesys system. Eur Spine J, 2009. 18(10): p. 1504-11.
40.Schulte, T.L., et al., The effect of dynamic, semi-rigid implants on the range of motion of lumbar motion segments after decompression. Eur Spine J, 2008. 17(8): p. 1057-65.
41.Niosi, C.A., et al., The effect of dynamic posterior stabilization on facet joint contact forces: an in vitro investigation. Spine (Phila Pa 1976), 2008. 33(1): p. 19-26.
42.Schmoelz, W., 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): p. 1276-85.
43.Niosi, C.A., et al., Biomechanical characterization of the three-dimensional kinematic behaviour of the Dynesys dynamic stabilization system: an in vitro study. Eur Spine J, 2006. 15(6): p. 913-22.
44.Bertagnoli, R., et al., Hybrid constructs. Orthop Clin North Am, 2005. 36(3): p. 379-88.
45.Fairbank, J.C. and P.B. Pynsent, The Oswestry Disability Index. Spine (Phila Pa 1976), 2000. 25(22): p. 2940-52; discussion 2952.
46.Carlsson, A.M., Assessment of chronic pain. I. Aspects of the reliability and validity of the visual analogue scale. Pain, 1983. 16(1): p. 87-101.
47.Chang TS, C.C., Wang CS, Chen HY, Chang JH, A new multidirectional tester for the evaluation of spinal biomechanics. JMBE, 2009. 29(1): p. 7-13.
48.Huang, R.C., et al., Biomechanics of nonfusion implants. Orthop Clin North Am, 2005. 36(3): p. 271-80.
49.Panjabi, M.M., Biomechanical evaluation of spinal fixation devices: I. A conceptual framework. Spine (Phila Pa 1976), 1988. 13(10): p. 1129-34.
50.Thompson, R.E., T.M. Barker, and M.J. Pearcy, Defining the Neutral Zone of sheep intervertebral joints during dynamic motions: an in vitro study. Clin Biomech (Bristol, Avon), 2003. 18(2): p. 89-98.
51.Maserati, M.B., et al., The use of a hybrid dynamic stabilization and fusion system in the lumbar spine: preliminary experience. Neurosurg Focus, 2010. 28(6): p. E2.
52.Liu, C.L., et al., Effect of the cord pretension of the Dynesys dynamic stabilisation system on the biomechanics of the lumbar spine: a finite element analysis. Eur Spine J, 2011.
53.Beastall, J., et al., The Dynesys lumbar spinal stabilization system: a preliminary report on positional magnetic resonance imaging findings. Spine (Phila Pa 1976), 2007. 32(6): p. 685-90.
54.Singh, K. and H.S. An, Motion preservation technologies: alternatives to spinal fusion. Am J Orthop (Belle Mead NJ), 2006. 35(9): p. 411-6.
55.Sengupta, D.K., Point of view: Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis. Spine (Phila Pa 1976), 2006. 31(4): p. 450.
56.James J. Yue, R.B., Paul C. McAfee, Howard S. An, ed. Motion Preservation Surgery of the Spine: Advanced Techniques and Controversies. Vol. Part VI: Lumbar Posterior Dynamic Stabilization: Pedicle Screw Based. 2009. 486-469.
57.Goel, V.K., et al., Test protocols for evaluation of spinal implants. J Bone Joint Surg Am, 2006. 88 Suppl 2: p. 103-9.
58.Wilke, H.J., K. Wenger, and L. Claes, Testing criteria for spinal implants: recommendations for the standardization of in vitro stability testing of spinal implants. Eur Spine J, 1998. 7(2): p. 148-54.
59.Patwardhan, A.G., et al., Compressive preload improves the stability of anterior lumbar interbody fusion cage constructs. J Bone Joint Surg Am, 2003. 85-A(9): p. 1749-56.