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A Novel, Minimally-Invasive Approach to Repair Degenerative Disk Disease in an Ovine Model Using Injectable Polymethyl-Methacrylate and Bovine Collagen (PMMA/BC)

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ABSTRACT

Background :

The natural, inflammatory repair processes of an injured intervertebral degenerative disc can propagate further injury and destruction. While there are many different treatment modalities of the pain related to degenerative disc disease, none are actually reparative in nature. Treatment strategies to repair a degenerative disc without inducing a destructive inflammatory milieu have been elusive. 

Purpose:

The purpose of this experiment is to discover the feasibility of reconstructing an injured intervertebral disc using an injected, inert polymer as the foundation for endogenous collagen growth.

Study Design:

In this ovine model of six subjects in total, we introduce a modality where a large inert polymer, polymethyl methacrylate (PMMA), in conjunction bovine collagen (BC) is injected into the intervertebral disc. Following six months of observation, histologic specimens were evaluated macroscopically and microscopically for evidence of a benefit of the injectable PMMA/BC.

Methods:

We obtained six merino sheep for this study. Concentric injuries were made to four of their lumbar intervertebral discs. Two of those levels were treated with a percutaneous injection of 0.3 cc of PMMA/BC. The remaining lumbar levels were left untreated and were our controls. After six months, all subjects were sacrificed. Their four levels were extracted and were examined macroscopically and microscopically.

Results:

All subjects tolerated the lumbar injury and percutaneous injection of PMMA/BC well. After the six month interval, all subjects have demonstrated an intact architecture of their lumbar disc height at the macroscopic and microscopic level. Microscopically, there was no evidence of external migration of the PMMA/BC microspheres, nor was there any evidence of an inflammatory response by its presence. Notably, the PMMA/BC microspheres were well-incorporated into the concentric disc tears and had undergone endogenous collagen formation in its environment. Treatment levels were revealing for maintenance of disc height without evidence of an ongoing degeneration. The controlled levels were revealing for continued disc degeneration with loss of disc height and evolving injury at the level of the concentric tear.

Conclusions:

This ovine model demonstrates a novel and promising technique for prevention and arrest of lumbar intervertebral disc degeneration.

No MeSH data available.


Related in: MedlinePlus

H&E slides show lack of any apparent inflammatory response seen in the annulus after 6 months. (Left: 1.25x magnification, Middle: 4x magnification, and Right: 20x magnification) . Large amounts of microspheres found within the annular lamellae with new collagen formation. Microspheres are present within tissue overlying annulus with an evident fibrotic response.
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FIG6: H&E slides show lack of any apparent inflammatory response seen in the annulus after 6 months. (Left: 1.25x magnification, Middle: 4x magnification, and Right: 20x magnification) . Large amounts of microspheres found within the annular lamellae with new collagen formation. Microspheres are present within tissue overlying annulus with an evident fibrotic response.

Mentions: These degenerative changes were seen macroscopically as disc narrowing, radial bulging, and vertebral osteophyte formation, along with nuclear clumping. Additionally, failure of annular patency led to disc space collapse. Microscopically, the H&E stains did not reveal any migration of the PMMA/BC microspheres from the inner and the outer annular fibers. This is demonstrated in Figure 6.


A Novel, Minimally-Invasive Approach to Repair Degenerative Disk Disease in an Ovine Model Using Injectable Polymethyl-Methacrylate and Bovine Collagen (PMMA/BC)
H&E slides show lack of any apparent inflammatory response seen in the annulus after 6 months. (Left: 1.25x magnification, Middle: 4x magnification, and Right: 20x magnification) . Large amounts of microspheres found within the annular lamellae with new collagen formation. Microspheres are present within tissue overlying annulus with an evident fibrotic response.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016043&req=5

FIG6: H&E slides show lack of any apparent inflammatory response seen in the annulus after 6 months. (Left: 1.25x magnification, Middle: 4x magnification, and Right: 20x magnification) . Large amounts of microspheres found within the annular lamellae with new collagen formation. Microspheres are present within tissue overlying annulus with an evident fibrotic response.
Mentions: These degenerative changes were seen macroscopically as disc narrowing, radial bulging, and vertebral osteophyte formation, along with nuclear clumping. Additionally, failure of annular patency led to disc space collapse. Microscopically, the H&E stains did not reveal any migration of the PMMA/BC microspheres from the inner and the outer annular fibers. This is demonstrated in Figure 6.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background :

The natural, inflammatory repair processes of an injured intervertebral degenerative disc can propagate further injury and destruction. While there are many different treatment modalities of the pain related to degenerative disc disease, none are actually reparative in nature. Treatment strategies to repair a degenerative disc without inducing a destructive inflammatory milieu have been elusive. 

Purpose:

The purpose of this experiment is to discover the feasibility of reconstructing an injured intervertebral disc using an injected, inert polymer as the foundation for endogenous collagen growth.

Study Design:

In this ovine model of six subjects in total, we introduce a modality where a large inert polymer, polymethyl methacrylate (PMMA), in conjunction bovine collagen (BC) is injected into the intervertebral disc. Following six months of observation, histologic specimens were evaluated macroscopically and microscopically for evidence of a benefit of the injectable PMMA/BC.

Methods:

We obtained six merino sheep for this study. Concentric injuries were made to four of their lumbar intervertebral discs. Two of those levels were treated with a percutaneous injection of 0.3 cc of PMMA/BC. The remaining lumbar levels were left untreated and were our controls. After six months, all subjects were sacrificed. Their four levels were extracted and were examined macroscopically and microscopically.

Results:

All subjects tolerated the lumbar injury and percutaneous injection of PMMA/BC well. After the six month interval, all subjects have demonstrated an intact architecture of their lumbar disc height at the macroscopic and microscopic level. Microscopically, there was no evidence of external migration of the PMMA/BC microspheres, nor was there any evidence of an inflammatory response by its presence. Notably, the PMMA/BC microspheres were well-incorporated into the concentric disc tears and had undergone endogenous collagen formation in its environment. Treatment levels were revealing for maintenance of disc height without evidence of an ongoing degeneration. The controlled levels were revealing for continued disc degeneration with loss of disc height and evolving injury at the level of the concentric tear.

Conclusions:

This ovine model demonstrates a novel and promising technique for prevention and arrest of lumbar intervertebral disc degeneration.

No MeSH data available.


Related in: MedlinePlus