Two X-rays, side by side. One shows the correct way to fill a disc space with bone graft. The other shows how 90% of spine surgeons do it.
Looking at the two images, can you spot the difference?
There’s a trick to fully and accurately filling the disc space with bone graft. And the trick is not immediately obvious. But once you know it, you will always want to use it.
Back to Basics
Bone graft is used in virtually every spine fusion surgery. Here’s a quote from the text book you probably used in school (Keith Bridwell, M.D. and Ronald DeWald, M.D., Chapter 3: Bone Grafting and Spine Fusion):
“Currently, more than 250,000 spine fusion procedures are carried out each year in the United States, and nearly all of these require bone graft material. Posterolateral lumbar fusion has been associated with the highest likelihood of failure (nonunion), ranging from 5% to 44% of patients with single level fusion, and more frequently when multiple level fusion, and more frequently when multiple levels are attempts. The successful repair of such pseudoarthroses is even more challenging, with failures occurring in 35% to 51% of revision attempts. Although many biologic and biophysical factors are involved in obtaining a successful arthrodesis, union depends in large part on the proper functioning of the bone graft material.”
Like anything else in life, getting the basics right is essential. And the “basics” set up everything that happens next. For spine fusion, it doesn’t get more basic than bone graft. After all…fusion with bone graft and no instrumentation is more likely than fusion with instrumentation but no bone graft.
In many important respects, bone graft is the actual implant while screws, rods, hooks and spacers are the scaffolding that maintains disc height while the bone graft promotes a successful fusion.
In 2009, Russell W. Nelson, M.D, founder and medical director of the Nelson Spine Institute in Thousand Oaks, California, and his business partner Jim Lynn, had one of those ah-ha! moments when they realized that spine surgeons weren’t optimizing their bone graft in fusion procedures.
And surgeons were using other strategies, notably BMP-2, PRP or cellular allografts to improve their fusion odds.
But what if the spine surgeon increased both the volume of bone graft and its coverage by some significant amount at just a fraction of the cost of BMP-2 or cellular allografts or even at NO additional cost?
Injecting Bone Graft
Designing a fusion system that accommodates integrated graft delivery means that you have to direct, control and contain the flow. That, in turn, led to Nelson and Lynn thinking about a cannulated tube, a large implant chamber and angled graft vents.
Nelson and Lynn named the company Pinnacle Spine Group, LLC.
Pinnacle’s first product, the InFill® lateral intervertebral body fusion device, received FDA clearance on February 21, 2011. The company later released three different TLIF footprints, all incorporating Pinnacle’s patented graft delivery technology.
Since then Pinnacle has sold 2,000 implants.
And surgeons who use the InFill system are reporting to the company 30-90% MORE bone graft volume delivered to the implant with the Pinnacle system.
And X-rays like the one above in our lead image.
The Ozgur Study
The first white paper for Dr. Nelson’s concept was performed by Burak M. Ozgur, M.D., Founder/Director of ONE Brain and Spine Center in Newport Beach, California, and Chief of Neurosurgery Spine at Hoag Hospital. Assisting him was his physician’s assistant, Erin Gleckman, PA-C.
Dr. Ozgur’s goal was to quantitatively measure and therefore evaluate the ability of Pinnacle’s InFill graft filling technique in the interbody space, with a cage.
Dr. Ozgur planned to pay particular attention to graft endplate surface contact.
He and Erin Gleckman used a full human cadaveric lumbar spine and performed a standard lateral approach discectomy and endplate preparation at four lumbar disc levels from L1-L5.
The two-person team then implanted standard lateral lumbar cages at each level and pre-packed them with standard graft material.
They then performed thin-cut CT scans with 3-D reconstructions to try to visually capture the standard cage and graft within the spine. With clear images, Dr. Ozgur and his assistant were hoping to be able to analyze the graft volume and endplate surface contact.
Pinnacle’s InFill lateral system technology was used at each level to inject additional graft material into the interbody spaces and cages. Ozgur and Gleckman then repeated the CT imaging and compared the images and measurement data.
Was there any change between pre-fill and post fill? And if so, what were they?
The Pilot Study’s Results
Using the InFill lateral system increased graft volume up to 94%, depending on the lumbar level.
At L1-L2, the pre and post injection graft volumes measured 3.038 and 5.115 cc, respectively. For those keeping score, that’s an increase of 2.077 cc or 68%.
At L2-L3, the pre and post injection graft volumes measured 3.136 and 5.376 cc, respectively. 71% increase.
At L3-L4, 35% increase. (The pre and post injection graft volumes measured 3.584 and 4.836 cc, respectively).
Finally, at L4-L5, 94% increase in graft volume! (The pre and post injection graft volumes measured 3.528 and 6.851 cc, respectively).
The InFill Product line
Conclusion
Pinnacle Spine Group’s patented InFill technology puts more bone graft into the intervertebral space. It’s just a basic, but critical, concept.
Volumetric analysis by 3-D CT scanning for Ozgur’s study showed a 35-94% increase in bone graft volume within in the disc space over traditionally pre-packed cages.
As we mentioned earlier, more than 2,000 InFill systems have now been used. Anecdotally, several of Pinnacle’s surgeons have found that better bone graft volume improves fusion rates and they have stopped using BMP.
