A biomimetic artificial intervertebral disc system composed of a cubic three-dimensional fabric (3DF Disc)

[Justin]

The Spine Journal
In Press, Corrected Proof, Available online 26 November 2009

A biomimetic artificial intervertebral disc system composed of a cubic three-dimensional fabric

Yasuo Shikinami PhDa, Yasuhiro Kawabe MSb, Kazuhiro Yasukawa MSb, Kaoru Tsuta BSb, Yoshihisa Kotani MD, PhDc and Kuniyoshi Abumi MD, PhDc. aShikinami Yasuo Institute, 6-301 Kyoto Research Park, 93 Awata-cho, Chudoji, Shimogyo-ku, Kyoto 600-8815, Japan. bTakiron Co., Ltd, Medical Division, 7-1-19 Minatojimaminamimachi, Chuo-ku, Kobe 650-0047, Japan. cDepartment of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kitaku, Sapporo 060-8638, Japan. Copyright © 2010 Elsevier Inc.

Background Context

In the quest for clinically functional artificial intervertebral discs (AIDs), multidisciplinary technologies have been employed. Existing solid mobile AIDs essentially consist of the superposition of solid plates and core materials; however, it is thought that an ideal surgical AID technology has not yet been developed. To overcome the limitation of these existing AIDs, we developed a unique flexible AID disc system on the basis of our original biomimetic concept. The AID is composed of a cubic three-dimensional fabric (3DF) with a triaxial fiber alignment, which offers biomimetic long-term dynamic mechanical behavior along with durability.

Purpose

This article substantiates the potential clinical use of the 3DF disc system that quite differs from existing ones.

Study Design

We designed the lumbar and cervical 3DF discs that improved the structural weaknesses caused by the collagenous fiber alignment of biological intervertebral disc. Bioresorbable hydroxyapatite particles were deposited on the surface layer of the 3DF disc to promote new bony ingrowth and to ensure secure binding at the interface of the contacting vertebral bodies. A stand-alone system was devised for surgical reliability in terms of both positioning and fixation, allowing tight press fitting with the vertebral bodies. Bioactive and bioresorbable pins were penetrated through the 3DF disc body and projected from the surface to allow ideal insertion and fixation to the disc space, preserving the precise position during dynamical movement. In vitro endurance of the 3DF disc was examined under long-term alternating stresses, and the in vivo animal tests were conducted in the intervertebral lumbar discs at L5–L6 excised from baboons and replaced with the lumbar 3DF disc.

Methods

The static mechanical endurance was assessed through a creep test. In vitro endurance of the 3DF disc under repetitive stresses including axial compressing, flexion-extension, torsional twisting, and lateral bending were applied to the 3DF disc for a long-term for up to 105 million stresses, which is roughly equivalent to exposure of natural biological movement for more than 50 years. In the animal test, eight baboons were euthanized 6 months postoperatively. To their extracted spines, six pure moments (flexion and extension, left and right lateral bending, and left and right torsion) were applied vertically to the superior end of the specimen and then values of range of motions (ROMs) were calculated. Histological analyses were conducted on 12 reticuloendothelial and systemic tissues.

Results

The 3DF disc retained its biomimetic “J-shaped” stress-strain behavior without generating wear debris for up to 105 million stresses. A 130-N loading for the creep test decreased the height of 0.3 mm during 80 to 1,000 hours. In the biomechanical test, ROM values of axial rotation and flexion-extension showed no significant difference from the intact excluding that of lateral bending because the location of each pin to stand alone certainly controlled the bending behavior only. The histological analysis indicated no significant pathologic changes induced by the 3DF disc.

Conclusions

The 3DF disc system is clinically suitable for human disc replacement arthroplasty based on the findings of long-term durability with dynamic motion in vitro and effective animal tests in vivo. This system surely overcomes the limitations of existing solid AIDs, and the clinical potential of the biomimetic 3DF discs has been verified. This new biomaterial technology delivers most of the functions and characteristics required by a clinically available AID if applied correctly by surgeons.

Artificial intervertebral disc; Cubic three-dimensional fabrics; Biomimetic; Long-term dynamic durability; Animal study

[Katie]

Justin, can you clarify please? I must be missing something. They speak of only 3D Fabric here, no metals in the makeup of this disc. Is this something that perhaps could circumvent my problems with metal allergies?

[Justin]

Justin, can you clarify please? I must be missing something. They speak of only 3D Fabric here, no metals in the makeup of this disc. Is this something that perhaps could circumvent my problems with metal allergies?

Hi Katie,

I read the full text and some other publications on the 3DF Disc. The 3DF Disc is a "bioactive three-dimensional fabric and bioresorbable hydroxyapatite/poly-l-lactide material." There is no metal in the 3DF Disc. The abstract that is posted above is an animal model where baboons were used. There are publications about the 3DF Disc from 2004, so they are making progress. Since this is an animal model, it is likely that the 3DF Disc won't be out anytime soon.

Here's a link to a publication from 2004 about the 3DF Disc: Two-year observation of artificial intervertebral disc replacement: results after supplemental ultra–high strength bioresorbable spinal stabilization.

I hope this helps.

[MDE]

Metal allergies have been circumvented through the use of coatings on the metal parts in hips and knees. Some companies have created "custom" (basically patient specific implants) for exactly this reason. You might try having your physician contact these companies to push for a similar option to be made available for disc replacements. If he has a good relationship with one or two, this option may be viable.

It hasn't been done in spine yet to my knowledge, so the timeline would be pushed out a bit, however the coating and base material could be the same so new testing might not have to be done. It would require looking at the already FDA approved discs (Charite would not be first choice)

[Carson]

Has anyone seen an image of the 3DF disc yet?

I've been researching this disc on and off for months and still have not seen an image of the disc.

[sportsnut3007]

I dont know for sure If I have seen this pic or not. This is definitely a kick butt type disc though. As you know it can be put in any freaking approach u want lol and no metal and no keels and all one material which I think will be less wear etc. But this bad boy is definitely the future with extreme lateral approach. In 10-15 this may be the best one out there and they will have stem cells mastered by then. If only I could degenerate normal and be late 40's till back issues lol in 20 years from now this will be mastered.

[Carson]

I find the 3DF to be very promising in theory as well. I'm going to combine google-powers with a net search ninja I know at work to see if I can't yield an image of this disc with his help. I've read over 50 related articles and no image of the disc. I can't even get a clear take on what company is manufacturing it. So far all I can find are the names of some of the developers via ncbi / pubmed pages.

[ajj1001]

who does it say the developers are?

[Carson]

The principle names of those involved in the testing, research and development seem to be are here on Spine Journal. It seems at least some of the development is taking place in Japan.

Y. Shikinami is a prominent name among the research employed by this company Takiron which produces biomedical materials. Pretty fascinating company.




Some of the key Names
----------------------------
Y. Shikinami 1, Y. Kotani 2, B. W. Cunningham 3, K. Abumi 2, K. Kaneda 2


1: Takiron Co., Ltd, Medical Div. 2-3-13, Osaka, Japan

2: Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan

3: Orthopaedic Biomechanics Laboratory, Union Memorial Hospital, Baltimore, MD 21218, USA

[Greg]

I find the 3DF to be very promising in theory as well. I'm going to combine google-powers with a net search ninja I know at work to see if I can't yield an image of this disc with his help. I've read over 50 related articles and no image of the disc. I can't even get a clear take on what company is manufacturing it. So far all I can find are the names of some of the developers via ncbi / pubmed pages.

Good one.....hope your ninja can turn up some results.