Total disc replacements

Putzier M et al (2006) Charite total disc replacement-clinical and radiographical results after an average follow-up of 17 years. Eur Spine J 15(2) 183-195... 

Total Disc Replacement Designs Using UHMWPE... 

Huang R.C., FP. Girardi, FP. Cammisa, Jr., and T.M. Wright. 2003. The implications of constraint in lumbar total disc replacement. Spine 28Suppl S412-417. 

Link H.D., and A. Keller. 2003. Biomechanics of total disc replacement. In The artificial disc. K. Biittner-Janz, S. Hochschuler, and P. McAfee, Eds. Berlin Springer Verlag. 

Kurtz, S. M., Peloza, J., Siskey, R. and Villarraga, M. L. Analysis of a retrieved polyethylene total disc replacement component. The Spine Journal 2004 5 344-50. 

Instead of total disc replacement, another approach is the replacement or reinforcement of the nucleus pulposus (NP) at the center of the disc with a material that can re-inflate the disc to restore disc height and function. Materials tested include stainless steel ball bearings, polymethylmethacrylate, and silicon, all without much success. More recently, NP implants have been made from cycle-6 cryogels fabricated from a mixture of PVA and polyvinyl pyrrolidone (PVP) with a ratio varying from 1 to 5 % by weight. The implants have been tested and found to better match the physical properties of the NP [92]. 

Future research efforts in IVD arthroplasty should focus on either partial or full disc functional restoration. This may include NP implants and/or reinforcement or total disc replacement. PVA-C, as a hydrogel, has many interesting properties, such as its long-term biocompatibility and nontoxicity. It is also strongly hydrophilic and viscoelastic with nonlinear stress-strain characteristics similar to the IVD. It has a very low coefficient of friction and has good wear resistance [23]. However, its strength is still too low to serve as a practical functional replacement of the annulus fibrosus. PVA-BC may further increase the strength of the PVA-C to make it a viable candidate material for IVD fabrication. 

Jacobs, W., Van der Gaag, N.A., Tuschel, A., et al. Total disc replacement for chronic back pain in the presence of disc degeneration. Cochrane Database Syst. Rev. 9, CD008326 (2012)... 

FIGURE 12.4 Four motion patterns of the UHMWPE Core in the CHARITfi total disc replacement observed during in vitro biomechanical testing. A With Motion Pattern 1, relative angular motion occurred predominantly between the superior endplate and the core, with little or no core translation. B In Motion Pattern 2, lift-off occurred by either the superior endplate from the core, or by the core from the inferior endplate. C In Motion Pattern 3, the UHMWPE Core locked in plane, resulting entrapment, over a portion of the flexion-extension range. D In Motion Pattern 4, angular motion occurred between the core and both the superior and interior endplates. Reproduced from [82] with permission. 

As summarized in Table 12.3, there are currently four lumbar total disc replacement designs incorporating UHMWPE in clinical use today CHARITE, ProDisc-L, Mobidisc, and Activ-L. In the previous section, we reviewed the clinical history and bioengineering studies related to the CHARITE. The three newer designs differ from the CHARITE in several respects, such as the amount of constraint in the bearing and the incorporation of keels into the endplates (Table 12.3). 

Wear and in vivo degradation are key functional aspects of total disc replacements. The majority of in vivo clinical... 

Based on the clinical experience of UHMWPE in total hip and knee replacements, the prodnction of wear debris from artificial discs, as well as from other motionpreserving spine implants, is a clinical concern. Wear debris indnced osteolysis has been implicated as a potential mechanism for late onset pain following the faUme of stainless steel and titanium instrumented fusions [65]. Osteolysis has also been observed around certain total disc replacement designs, such as the Acroflex artificial disc [66], and case smdies of osteolysis around CHARITE disc replacements have also been reported [67-69]. According to recent conference presentations, the UHMWPE particle load around long-term implanted artificial discs may be comparable to total hip arthroplasty [70], and the periprosthetic particle concentration appears to be correlated with a local inflammatory response [71]. Although the occurrence of osteolysis with metal-on- X)lyethylene total disc replacements has thus far been relatively rare, the long-term wear behavior of artificial discs remains of clinical importance [69]. 

Total disc replacement is a new, promising field of spine implant technology that has the potential to revolutionize the treatment of degenerative disc disease. Today, conventional UHMWPE is incorporated in both cervical and lumbar disc arthroplasty. It is clear from both in vitro and clinical data that disc replacements can successfully preserve the motion of treated spinal level. Aside from patient satisfaction and the speed of recovery, there are modest clinical benefits with disc replacement that manifest in the short term as compared with fusion. Furthermore, unlike fusion procedures, disc replacements may also need to be revised due to poor implantation technique or failure of the device. On the other hand, over the long term, the primary benefit of disc replacement is expected to be the reduced incidence of adjacent segment degeneration, which will hopefully offset the new, and as yet, poorly quantified risks associated with the technology. It will be many years, probably over a decade, before sufficient... 

This chapter was supported in part by NIH ROl AR47192. This chapter was not written with the financial support of any manufacturer of total disc replacements. However, all of the producers of disc replacements, whose products are mentioned in this review, were contacted by the author and given the opportunity to verify the factual accuracy of the information related to their products. 

Link HD, Keller A. Biomechanics of total disc replacement. In Biittner-Janz K, Hochschuler SH, McAfee PC, editws. The artfi-cial disc. Berhn Springer 2003. p. 33-52. 

Blumenthal S, McAfee PC, Guyer RD, Hochschuler SH, Geisler FH, Holt RT, et al. A prospective, randomized, multicenter Food and Drug Administration investigational device exemptions study of lumbar total disc replacement with the CHARITE artificial... 

Kurtz SM, MacDonald D, lanuzzi A, van Ooij A, Isaza J, Ross ERS. In vivo oxidation and oxidation potential for polyethylene in total disc replacement following gamma sterilization in air and first-generation barrier packaging. Trans of the 54th Orthop Res Soc 2008 33 1324. 

Cunningham BW, Dmitriev AE, Hu N, McAfee PC. General principles of total disc replacement arthroplasty seventeen cases in a nonhuman primate model. Spine 2003 October 15 28(20) S118-24. 

O Leary P, Nicolakis M, Lorenz MA, Voronov LI, Zindrick MR, Ghanayem A, et al. Response of CHARITfi total disc replacement under physiologic loads prosthesis component motion patterns. Spine J 2005 November-December 5(6) 590-9. 

Tropiano Jr P, Huang RC, Girardi FP, Cammisa FP, Marnay T Lumbar total disc replacement. Seven to eleven-year follow-up. J Bone Joint Surg 2005 March 87(3) 490-6. 

Huang RC, Girardi FP, Cammisa Jr FP, Lim MR, Tropiano P, Marnay T Correlation between range of motion and outcome after lumbar total disc replacement 8.6-year follow-up. Spine 2005 June 15 30(12) 1407-11. 

Mayer HM, Wiechert K, Korge A, Qose I. Minimally invasive total disc replacement surgical technique and preliminary clinical results. Eur Spine J 2002 October ll(Suppl. 2) S124-30. 

Delamarter RB, Bae HW, Pradhan BB. Clinical results of ProDisc-II lumbar total disc replacement report from the United States clinical trial. Orthop Clin North Am 2005 July 36(3) 301—313. 

Shim CS, Lee S, Maeng DH, Lee SH. Vertical split fracture of the vertebral body following total disc replacement using ProdDisc report of two cases. J Spinal Disord Tech 2005 October 18(5) 465-9. 

Delamarter R, Zigler J, Goldstein J. 5-year results of the prospective, randomized, multicenter FDA invesigafional device exemption (IDE) Prodisc-L total disc replacement clinical triak Transactions of die Spineweek 2008 meeting. Geneva, Switzerland 2008 May 26—31. C3. 

Auerbach JD, Jones KJ, Fras Cl, Balderston JR, Rushton SA, Chin KR. The prevalence of indications and contraindications to cervical total disc replacement. Spine J 2007 November 3. 

Chin KR. Epidemiology of indications and contraindications to total disc replacement in an academic practice. Spine J 2007 July-August 7(4) 392-8. 

Bertagnoli R, Duggal N, Pickett GE, Wigfield CC, Gill SS, Karg A, et al. Cervical total disc replacement, part two clinical results. Orthop CUn North Am 2005 July 36(3) 355-62. 

Kurtz S, Siskey R, CiccarelU L, van Ooij A, Peloza J, Villarraga M. Retrieval analysis of total disc replacements implications for standardized wear testing. J ASTM hit 2006 3(6) 1—12. 

Wright T, Cottrell J. Retrieval analysis of ProDisc total disc replacements. 7th annual meeting of the Spine Arthroplasty Society. BerUn, Germany 2007 May 1-4. P124. 

Choma TJ, Miranda J, Siskey R, Baxter RM, Steinbeck MJ, Kurtz SM. Retrieval analysis of a ProDisc-L total disc replacement J Spin Disord Tech 2008 12. In Press. 

FIGURE 34.6 Photograph and microCT rendering of a mobile bearing total disc replacement. This component was implanted for 11 years. 

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