activ L™ FDA Clinical Trial Site(s)

[Slackwater]

There is an activ L™ (Aesculap Implant Systems, aka Braun) clinical FDA trial with US-based surgeons.
ClinicalTrials.gov shows two (2) sites in the trial, listed below: Yale and Aventura Hospital. In addition not listed is Rush Univ. Med School lists Dr. Deutsch with an ongoing activ L™ trial. UCSF ~may be participating.


Listed, Recruiting
James Yue, MD
Yale University
Orthopædics and Rehabilitation
Yale Physicians Building
800 Howard Avenue
P.O. Box 208071
New Haven, CT 06520-8071
Appointments (203) 737-5656
Yale Orthopaedics Clinical Trials


Listed, Not Recruiting
Dr. Rolando Garcia
Aventura Hosptial and Medical Center
21000 N.E. 28 Ave, Ste 104
Aventura FL 33180
Phone: 305-937-1999
Fax: 305-931-6554
Dr. Garcia may have been the first surgeon to implant the activ L™ in the U.S, January 30, 2007.


Not Listed on ClinicalTrials.gov, Ongoing Trial
Harel Deutsch, MD
Co-director, Rush Spine and Back Center
1725 W. Harrison St. Ste. 970
Chicago, IL 60612
Phone: (312) 942-6644
Fax: (312) 942-2176
Dr. Deutsch has ongoing trials listed @ the bottom of this page/link.


Not Listed on ClinicalTrials.gov, possible future involvement
Dr. Christopher Ames
Co-director of the UCSF Spine Center and UCSF Neurospinal Surgery
UCSF Spine Center
400 Parnassus Ave. 3rd Floor
San Francisco, CA 94143
(415) 353-7500
(866) 81-SPINE or (866) 817-7463
A newsletter, on page 6, mentioned Dr. Ames / UCSF will serve as an investigational device site for activ-L™.



A recent post asked about surgeons for a 3-Level ADR (longer than FDA approved 1-Level ADR) for a person in Georgia. I mentioned Dr. Garcia, a surgeon in Florida.

Please assume that an artificial disc is not appropriate for everyone. I think the FDA has "approved" its use in adults up to age 60 who have a single degenerative disc in one of the two lowest lumbar discs (?and have never had a fusion operation?) A compassionate use request may allow a deviation from the rules.

[Liz]

i read on a spine consultant's site that Dr. John Regan in LA is also implanting Activ-L (along with Prodisc and Charite). The Activ-L trial is not listed on Dr. Regan's website under clinical trials, and i have not personally confirmed what trials he is participating in since i don't want any more ADRs in my lumbar spine for a while.

[Harrison]

I believe Texas Back Institute can be added to the list too! Dr. Blumenthal has performed at least a few. It's too bad this effort to present (what should be) clear and obvious information is being done by patients -- what's wrong with Aesculap Implant Systems?!

PS: Thanks for posting this Slack. I emailed you recently and I don't think it went through...email me when you can.

[Don]

For what it's worth, I thought maybe this was a new Activ-L multi-level trial and contacted them today, but it's the single level trial, which has been on-going. Maybe I should've known that.

[Slackwater]

Originally posted by Don:
For what it's worth, I thought maybe this was a new Activ-L multi-level trial and contacted them today, but it's the single level trial, which has been on-going. Maybe I should've known that.

Thank you for calling Aesculap Implant Systems, appreciated.

The presentation "In-vitro flexibility in the lumbar spine before and after total disc arthroplasty", May 2007, is on activL, it is a PDF, ~18KB. The paper, an abstract(?), is not listed on PubMed. The author is listed several times on pubmed, TM Grupp, Aesculap AG & Co. KG, Forschung und Entwicklung, Am-Aesculap-Platz, 78532 Tuttlingen.

The testing includes "axial preload", not certain but I think this means similar to the testing protocol done by Dr. Panjabi, Dr. Goel and Dr. Lotz. Need to re-read other papers to remember, not a mechanical engineer. Scratching my head because they tested L2/3 and L4/5 (L4/5, L5/S1 may have made more sense?). The good news is a document on spine kinematics/biomechanics with activL(lumbar artificial disc). Dr. Yue and Dr. Garcia are listed as co-authors(?).

The document is found the European Federation of Othropaedics and Traumatology EFORT in the May 2007 meeting notice, abstracts/papers.

[Slackwater]

PEEK = polyetheretherketone

PEEK is mentioned as a possible future activL® (Aesculap Implant Systems/BBraun) material in a short abstract at BioSpine2. There are multiple references to PEEK in PUBMED, one of them authored by S. Kurtz (Drexel/Exponent) below the activL abstract. Carbon fiber reinforced PEEK appears quite strong. PEEK produces fewer wear particles than polyethylene-metal parts or metal-metal parts. PEEK wear particles are also less bio-reactive than metal or apparently polyethylene.

Artificial knee & hip joints (THK, THA) provide most of the metrics on joint implants, wear particles in regards to osteolysis and "survivorship". Survivorship means revision not required. Survivorship rates vary from 100% just as with the intervertebral disc & ADR. Another example of THA might be 96.8% survivorship at 7 years, n = 35,041, again the rates vary. The ADR/TDR in the spine gets many cycles over 30-50 years. I think the motion in the spine/intervertebral disc joint is not as large a motion as compared to either the knee or hip.

Net result is wear particles can develop ostelysis around an implant, (os·te·ol·y·sis Definition: loss of bone: the gradual disintegration of bone).


BIOSPINE 2nd International Congress Biotechnologies Spinal Surgery, Germany, Sept. 20th–22nd, 2007 1.4 MB
Alternative Material concepts in Artificial Disc Replacement
Jens Beger, T. M. Grupp, J. Schwiesau, W. Blömer
B. Braun Aesculap, Tuttlingen, Germany

Introduction: The intervertebral disc is a complex anatomic and functional structure, which makes the development of an efficient artificial disc a challenge. Over time, there have been a number of total disc design concepts incorporating the use of different materials. While some of these designs utilize polymer technologies, the majority of the current totals disc designs are mechanical in nature often incorporating a ball and socket style design. The objective of our study is to discuss potential alternative material concepts which could fulfi ll the challenging
requirements.

Methods: A review of state of the art materials was done and the potential applications for artificial disc replacement were discussed and evaluated. The currently used designs are composed of materials commonly found in orthopaedic devices. Also alternative materials are on the radar screen anticipating improved behaviour regarding kinematics, biotribology, MRI compatibility and radiolucency. Some promising materials were selected and a screening test program has been started using in-vitro wear simulation according to ISO/DIS 18192-1.

Results: Alternative materials seem to have the potential for improved new artificial disc replacement designs. As an example the tribological behavior of a PEEK based material shows encouraging results in a first screening evaluation.

Conclusion: Promising alternative materials can be considered for artificial disc replacement. However further indepth investigations regarding fatigue behavior, bone integration, particle release and the corresponding biological response are necessary.


Biomaterials. 2007 Nov;28(32):4845-69 PMID 17686513
PEEK biomaterials in trauma, orthopedic, and spinal implants
Steven M. Kurtz (a,b), John N. Devine (c)
a Exponent, Inc., 3401 Market Street, Suite 300, Philadelphia, PA 19104, USA
b School of Biomedical Engineering, Science, and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
c Invibio Ltd., Thornton-Cleveleys, UK

"PEEK has had the greatest clinical impact in the field of spine implant design, and PEEK is now broadly accepted as a radiolucent alternative to metallic biomaterials in the spine community. For mature fields, such as total joint replacements and fracture fixation implants, radiolucency is an attractive but not necessarily critical material feature."
(c) 2007 Elsevier Ltd. All rights reserved.


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ADR/TDR materials in the future may be PEEK or possibly certain new types of ceramics (Amedica ?). Scratching my head if the activL® FDA Clinical Trial could include PEEK, or Ceramic material instead of the current design (metal-UHMWPE.cross-linked?).

Aesculap Implant Systems is a subsidiary of BBraun that makes Ceramic-on-Ceramic hip joints. The good news on Braun's ceramic hip: minimal wear, scratch resistant and biologic compatibility. The challenge, I think, is blurred imaging because of the alumina construction.

S-->

[Slackwater]

Activ-L™ is written about in the below. I have not seen the below published on PubMed.gov, other society publications, or at the Stanford NeuroMuscular Biomechanics Lab (NMBL pubs). Put it in context, I may be looking at it & not recognize it.


2006 Congress of Neurosurgeons Annual Meeting, Chicago
Format: Digital Poster

Biomechanical Study of Lumbar Spinal Arthroplasty with a Semi-constrained Artificial Disc (Activ L) in the Human Cadaveric Spine (link)

Authors: Se-Hoon Kim, MD, PhD; Ung-Kyu Chang, MD, PhD; T. Jesse Lim, PHD; Daniel H. Kim, MD

Abstract: Introduction: The authors evaluated the biomechanical features i.e. range of motion (ROM), disc pressure (DP) and facet strain (FS) of Activ L-implanted cadaveric spines. The prosthesis is a metal-on-plastic semi-constrained device having a mobile core offering sagittal translational movement of the center of rotation.

Methods: Five cadaveric human lumbosacral spines were tested in the intact state and after an L4-L5 arthroplasty with the Activ L under physiologic compressive follower preload. A video-based motion-capturing system, pressure transducer needles inserted into the L3-L4 and L5-S1 discs, and FS gauges were used for the measurement. The compressive preload was applied along the follower path, approximating the tangent to the lumbar curve passing through the centers of rotation of the lumbar segments.
Baseline ROM, DP, and FS were measured in different modes of motion by applying loads up to 8 Nm, with a constant 400 N axial follower preload. After the AD was implanted at the L4-L5 disc level, measurements were repeated in the same manner.

Results: The Activ L arthroplasty revealed a significant decrease of ROM at the operative segment during rotation, and significant increase during flexion and bending at the operative segment and during flexion at the inferior segment. Though the results were not consistent at the superior disc, the central DP decreased in all the motion modes at the inferior disc without a statistical significance. For FS, a significant decrease was detected during flexion at the operative facet and during rotation at the inferior facet.

Conclusions: To reduce the incidence of adjacent segment disease, the compensatory decrease of the adjacent segment motion, DP, and FS should be made theoretically by the use of an artificial disc. In our study, however, such a change was noted only in part, and further investigation using a larger series of specimens is needed in the future studies.