Disc replacement

Taksali, S., Grauer, J.N., and Vaccaro, A.R., Material considerations for intervertebral disc replacement implants. Spine J., 4, 231S-238S, 2004. 

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... 

Weigh the tablets (see Note 1 below). Introduce the tablets into the rotating disc. Replace the cover, then fix the rotating disc to the tester. 

Materials for intervertebral disc replacement — Interpenetrating polymer networks based on crosslinked poly(vinyl alcohol) were prepared by impregnating the PVA matrix with hydrophilic and hydrophobic monomers and subsequently irradiating with gamma rays [22],... 

H.D. Link, PC. McAfee, L. Pimenta, Choosing a cervical disc replacement, Spine J. 4 (2004) S294-S302. 

Shift difficulty or can not shift Large free stroke of clutch pedal clutch Pipe has air Failure of clutch cylinder Failure of clutch master cylinder The installation position of clutch disc is not in position large deviation oil on the friction lining or broken The clutch disc is dirty or with foreign material Failure of clutch cover Adjust the free stroke of pedal Disehaige the air in clutch system Replaee replace Inspect the clutch disc replace Repair if necessary Replace... 

Total Disc Replacement Designs Using UHMWPE... 

The SB Charity is an unconstrained implant. As such, it is capable of reproducing pure A-P and lateral translation of the cephalad vertebral body even without rotation (Huang et al. 2003). The lAR of this disc replacement lies within the disc space, and because of its imconstrained nature it is mobile and as such can compensate for deviations from adequate placement (Huang et al. 2003). In flexion-extension due to its three-component set up including the sliding core. 

The first generation PRODISC was designed in France by Dr. Thierry Mamay in the late 1980s and was first implanted in early 1990. In conjunction with Dr. Villette, they implanted this disc replacement in a total of 64 patients from 1990 until 1993 and decided to follow them long term (Mamay 2003, Spine Solutions 2002b). The PRODISC II was described as an improvement over the first design and was launched in the European market in December 1999 (Tropiano et al. 2003). 

Another study following 53 patients in Europe implanted with the PRODISC between December 1999 and December 2001 provides a follow-up evaluation after a mean period of 1.4 years (Tropiano et al. 2003). In this group of patients complete satisfaction was reported by 87% with satisfaction in 13%. Complications reported in 9% of the patients included a vertebral body fracture, malposition, and persistent radicular pain. In this group of patients there were statistically significant improvements in the VASs and ODQ scores following implantation. Bertagnoli and Kumar also report on 1-year follow-up on 108 patients who received a total of 134 disc replacements (2002). Of these patients 90.8% showed excellent results with an increased ROM. 

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. 

Mamay T. 2003. Lumbar disc replacement, 7-11 years results with PRODISC. Eur Spine ilSuppl S19. 

McAfee PC., I.L. Fedder, S. Saiedy, et al. 2003. SB Charite disc replacement Report of 60 prospective randomized cases in a U S. center. Spine 28Suppl S424-433. 

Tropiano R, R.C. Huang, F.P. Girardi, and T. Mamay. 2003. Lumbar disc replacement Preliminary results with ProDisc II after a nunimum follow-up period of 1 year. Spine 28SuppI S362-368. 

Van Ooij A., RC. Oner, and A.J. Verbout. 2003. CompUcations of artificial disc replacement A report of 27 patients with the SB Charite disc. Spine 28SuppI S369-383. 

Zeegers W.S., L.M. Bohnen, M. Laaper, and M.J. Verhaegen. 1999. Artificial disc replacement with the modular tjqje SB Charite III 2-year results in 50 prospectively studied patients. Eur Spine J 8 210-217. 

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. 

Mizuno, H., Roy, A.K., Vacanti, C.A, Kojima, K., Ueda, M., and Bonassar, L.J. (2004) Tissue-engineered composites of anulus fibrosus and nucleus pulposus for intervertebral disc replacement. Spine, 29 (12), 1290-1297. 

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. 

Nerurkar, N.L., Sen, S., Huang, A.H., Elliott, D.M., Mauck, R.L., 2010. Engineered disc-like angle-ply structures for intervertebral disc replacement. Spine 35 (8), 867—873. 

Puelacher,W.C.,Wisser,J.,Vacanti,C. A., Ferraro,N.E,JaramiUo,D., Vacant , J.P.1994.Temporomandibular joint disc replacement made by tissue-engineered growth of cartilage. / Oral Maxillofac Surg 52(ll) 1172-7. 

Cason, G.W., Herkowitz, H.N. Cervical intervertebral disc replacement. J. Bone Joint Surg. Am. 95, 279-285 (2013)... 

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)... 

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