Innospine Assessing Symptomatic Back Pain:
An Interview with David Miller of Innospine

What is the need you set out to address?

I was part of the first class of Biodesign Innovation Fellows in 2001-02. Toward the end of the fellowship, I was researching several needs related to the spine. Through my Stanford Biodesign contacts, I was introduced to Dr. Todd Alamin, who is a spine specialist in the Department of Orthopaedic Surgery at Stanford. He told me how frustrated he was by the fact that, while many surgeries to improve low back pain were successful, there were still patients who weren’t helped by surgery and occasionally these invasive procedures made the problems worse. We discussed the need for a better way to assess the source of lower back pain that would help determine ahead of time whether surgery would be effective in bringing each patient relief.  Todd and I teamed up, and we pursued this need by following the biodesign innovation process.

What key insight was most important to guiding the design of your solution?

One of the tests physicians use to find the specific cause of persistent, unresolved low back is provocative discography. In this procedure, the patient lays on a table while needles are inserted into the discs suspected of causing weakness or pain. Fluid (usually a radiopaque contrast dye) is injected into one disc at a time and, and the patient rates the pain caused by the pressurization in terms of intensity and similarity to his or her typical pain level. If the pressurization causes familiar pain, that disc is considered the source of the pain and surgery or other treatment follows.

“ delivering an anesthetic to specific discs one at a time...we could more accurately predict the outcome of a corrective surgery and more precisely assess the involvement of individual discs.”

This diagnostic approach is problematic for several reasons. First, the patient is immobilized and uncomfortable during the procedure. Second, subjectively assessing pain quality and magnitude is imprecise. Third, it’s hard to get a needle into the disc and the pain caused by the needle sticks can last for a long time, making it difficult to determine which specific discs are the source of the patient’s normal low back pain. We thought that by delivering an anesthetic to specific discs one at a time, and then having the patient replicate movements that were previously painful, we could more accurately predict the outcome of a corrective surgery and also more precisely assess the involvement of individual discs.

How does your solution work?

The InnoSpine Function Anesthetic Catheter is a small, flexible catheter that anchors securely in the disc space after insertion. The physician delivers a local anesthetic through the catheter while the patient is ambulatory and performing activities that would normally cause pain. The anesthetic mimics the effects of surgery, making it easier for the physician to predict procedural success. So if the patient’s pain on the delivery of the anesthetic goes from a 9 to a 0, we know that surgery is likely to reduce that patient’s pain long term. If it goes from a 9 to a 6, then surgery is less likely to be helpful, and further, that other remedies would be more appropriate.

“The catheter makes the care options clearer to the patient because it’s like a temporary test drive of a surgical procedure.”

Our solution also helps pinpoint problematic discs more precisely. If multilevel – more than one disc –  disease is suspected, the physician can use multiple catheters and inject the discs one at time to more accurately determine the specific level or levels that are involved.

David MillerDavid Miller

One of the best parts about the technology is that it gets patients and providers on the same side; before this procedure, patients sometimes felt as though spine surgeons had solutions they simply weren’t making available. The catheter makes the care options clearer to the patient because it’s like a temporary test drive of a surgical procedure. In doing so, the InnoSpine procedure aligned the expectations of the patient and surgeon, allowing more informed treatment decisions.

At what stage of development is your solution?

We obtained 510(k) clearance for the device and did our first cases here at Stanford. The technology was then acquired by Kyphon, which was subsequently acquired by Medtronic.  The device was in patient care for several years and then discontinued.

Tell us about a major obstacle you encountered and how you overcame it.

We actually encountered a number of problems that ultimately proved too big to overcome. First, we couldn’t easily conduct a clinical trial because there was no gold standard diagnostic test to which we could compare our technology. Instead, we would need to rely on surgical outcomes on heterogenous patient populations.  In the end, the size of the study required to power meaningful claims was cost-prohibitive and was never conducted.  Because of this lack of strong evidence, we couldn’t make defensible, FDA-cleared claims, and as a result we were unable to get reimbursement.

Another issue was that using our diagnostic device required spine surgeons change the way that they diagnosed their patients to determine the most appropriate therapies for their patients. Without strong evidence, many surgeons were unwilling to pay for the device and use the information to alter their practice.

What role did your Biodesign training play in enabling you to design, develop, and/or implement this solution?

I came to Stanford Biodesign as a mechanical engineer and came out as an entrepreneur. The fellowship helped me understand all of the elements that are required to transform a need and solution idea into a real medical device company, from hiring consultants to pursuing regulatory approval and funding. In addition, the network of contacts I developed through the fellowship was invaluable – in fact without it, I wouldn’t have met Dr. Alamin in the first place.

Reflecting on your experience, what advice do you have for other innovators?

In order to be an entrepreneur, it’s essential to understand the big picture.

David Miller co-founded InnoSpine from the 2001-02 Biodesign Innovation Fellowship with Dr. Todd Alamin.

Disclaimer of Endorsement: All references to specific products, companies, or services, including links to external sites, are for educational purposes only and do not constitute or imply an endorsement by the Byers Center for Biodesign or Stanford University.

Close-up of catheter tip.
Early cadaver study.
Early work in the clean room.
First in human testing.
Image from the product brochure.
Image from the product brochure.

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