Artificial facet replacement

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Research is ongoing in the efficacy determination of artificial replacements for the facet joints of the human spine.

An artificial facet replacement is a joint prosthesis intended to replace the natural facets and other posterior elements of the spine, restoring normal (or near-normal) motion while providing stabilization of spinal segments. It is typically used as an adjunct to laminectomy, laminotomy, neural decompression, and facetectomy, in lieu of standard lumbar fusion.[1] The prosthesis is indicated for back and leg pain caused by central or lateral spinal stenosis, degenerative disease of the facets with instability, and grade 1 degenerative spondylolisthesis with objective evidence of neurological impairment.[1]

History[edit]

Patents related to facet replacement have been around since the 1980s; more intense research into artificial facet replacement as an effective and marketable prosthesis has been ongoing since the mid-2000s.[2] Prominent researched options include:

  • ACADIA: a facet replacement implant "designed to reproduce facet motion while restoring normal stability and motion," first tested in 2006; also known as the Anatomic Facet Replacement System (AFRS); clinical trials still ongoing as of September 2015[2][3][4]
  • TOPS: a total posterior arthroplasty system first tested in 2006; clinical trials completed in 2011[2][5][6]
  • TFAS: the Total Facet Anthroplasty System, a nonfusion spinal implant originally developed by Archus Orthopedics in 2005; clinical trial status unknown since February 2009, when the company was dissolved but then acquired by Facet Solutions, then Globus medical; status unknown[2][7][8]

Current status and efficacy[edit]

In 2011, in a retrospective and future analysis of the technology in the International Journal of Spine Surgery, Serhan et al. opined that artificial facet replacement still had much to prove:

In the future, facet replacement devices will require a substantial amount of validation testing and numerous clinical studies before they can be considered a viable treatment option for the treatment of spinal disorders. To date, most pathophysiologic research and thus surgical treatments have been focused on the disc as a pain generator. A more comprehensive focus on re-establishing the structure and function of the human functional spinal unit may include facet replacement. A better understanding of facet function and facet-mediated pain, possibly through classification of facet degeneration, may be needed to support the use of such devices.[2]

More recently, an August 2014 critique by Dr. Domagoj Coric in the journal Neurosurgery has suggested that research aside, at least in the United States the regulatory process has led to "time lag inherent in the design, development and implementation of new technologies" such as artificial facet replacement, noting that both ACADIA and TOPS were still not FDA-approved within the U.S.[1]

In the short-term, study literature has provided "insufficient support" for the prosthesis, with pessimal results for the procedure.[9]:168[10] However, more long-term results (such as those from the seven-year follow-up on TOPS implants) have been encouraging, albeit limited by patient sample size.[5]

See also[edit]

Further reading[edit]

References[edit]

  1. ^ a b c Coric, D. (2014). "Spinal technologies not available in the United States: An editorial". Neurosurgery. 61 (Supplement 1): 26–29. doi:10.1227/NEU.0000000000000398. PMID 25032526. 
  2. ^ a b c d e Serhan, H.; Mhatre, D.; Defossez, H.; Bono, C.M. (2011). "Motion-preserving technologies for degenerative lumbar spine: The past, present, and future horizons". International Journal of Spine Surgery. 5 (3): 75–89. doi:10.1016/j.esas.2011.05.001. PMC 4365627Freely accessible. PMID 25802672. 
  3. ^ "A Pivotal Study of a Facet Replacement System to Treat Spinal Stenosis". ClinicalTrials.gov. U.S. National Institutes of Health. 9 September 2015. Retrieved 17 February 2016. 
  4. ^ Goel, V.K.; Mehta, A.; Jangra, J.; Faizan, A.; Kiapour, A.; Hoy, R.W.; Fauth, A.R. (2007). "Anatomic Facet Replacement System (AFRS) Restoration of Lumbar Segment Mechanics to Intact: A Finite Element Study and In Vitro Cadaver Investigation". International Journal of Spine Surgery. 1 (1): 46–54. doi:10.1016/SASJ-2006-0010-RR. PMC 4365566Freely accessible. PMID 25802578. 
  5. ^ a b Anekstein, Y.; Floman, Y.; Smorgick, Y.; Rand, N.; Millgram, M.; Mirovsky, Y. (2015). "Seven years follow-up for total lumbar facet joint replacement (TOPS) in the management of lumbar spinal stenosis and degenerative spondylolisthesis" (PDF). European Spine Journal. 24 (10): 2306–14. doi:10.1007/s00586-015-3850-0. PMID 25749724. Retrieved 17 February 2016. 
  6. ^ "Safety and Effectiveness Study of the TOPS System, a Total Posterior Arthroplasty Implant Designed to Alleviate Pain Resulting From Moderate to Severe Lumbar Stenosis". ClinicalTrials.gov. U.S. National Institutes of Health. 17 May 2011. Retrieved 17 February 2016. 
  7. ^ Voronov, L.I.; Harvey, R.M.; Sjovold, S.G.; et al. (2009). "Kinematics of total facet replacement (TFAS-TL) with total disc replacement". International Journal of Spine Surgery. 3 (3): 85–90. doi:10.1016/j.esas.2009.09.002. PMC 4365598Freely accessible. PMID 25802631. 
  8. ^ "Total Facet Arthroplasty System®(TFAS®) Clinical Trial". ClinicalTrials.gov. U.S. National Institutes of Health. 4 February 2009. Retrieved 17 February 2016. 
  9. ^ Gil, K.S.L. (2013). "Chapter 12: Anesthesia for Spinal Cord Injury Surgery". In Mongan, P.D.; Soriano, S.G.; Sloan, T.B. A Practical Approach to Neuroanesthesia. Philadelphia, PA: Lippincott Williams & Wilkins. pp. 148–191. ISBN 9781451173154. Retrieved 17 February 2016. 
  10. ^ Ozer, A.F.; Suzer, T.; Sasani, M.; Oktenoglu, T.; Cezayirli, P.; Marandi, H.J.; Erbulut, D.U. (2015). "Simple facet joint repair with dynamic pedicular system: Technical note and case series". Journal of Craniovertebral Junction & Spine. 6 (2): 65–68. doi:10.4103/0974-8237.156049. PMC 4426524Freely accessible. PMID 25972711.