New spinal fixation technique: an interview with Dr. Ian Armstrong, Medical Director, Southern California Spine Institute

insights from industryIan I.T. Armstrong, M.DMedical Director, Southern California Spine Institute

Please can you give a brief introduction to the most common type of spinal fixation, pedicle screw fixation?

Traditionally, the most commonly used medical devices for spinal fusion procedures have been pedicle screws and rods, and interbody cages or spacers. Each are coupled with bone grafts and limit movement while the area being fused heals.

Pedicle screws are most common, and are conventionally inserted deep into the body of consecutive vertebrae; a small rod is then attached to “fix” or connect the screws. This fixation prevents movement within the segments thus fusing the spine in that area.

What are the main limitations of this technique?

While the pedicle screw and rod fusion method is still a gold-standard for most spine surgeons across the globe, there are some limitations.

There is a steep learning curve associated with the placement of the screws; therefore patients should do their homework prior to selecting a surgeon to perform their procedure. There is also a risk of breakage with pedicle screws, with a rate estimated at about one in 1,000.

Additionally, there can be complications that arise from infections due to the moderately invasive nature of the procedure. And most concerning is the potential for nerve root damage due to the proximity in which screws routinely come to spinal nerves.

Could you please outline the new technique ZIP, which has been developed by Aurora Spine? How does this differ from pedicle screw fixation?

The ZIP™ fixation device is unique in that it fuses adjacent vertebrae via the spinous process – the parts of your spine which you can feel sticking out when you run your fingers down the length of your spine. 

Interspinous process fixation (ISP), as it’s called, has been shown to be a safe and effective alternative to the traditional methods described in the previous questions.

While still relatively new, Aurora Spine’s devices have been shown to deliver a reliable fusion rate while offering additional benefits in comparison to alternative methods.

Since ISP devices like ZIP™ don’t interfere with adjacent facet joints, they have the potential to decrease the incidence of adjacent segmental degeneration – a common complication post fusion surgery. 

How was the ZIP technique developed and what made this innovation possible?

The ZIP device was developed by Aurora CEO Trent Northcutt who was a former surgical nurse familiar with fusion procedures. Years later he was working as a technology executive and after ratcheting a zip tie too tightly, he realized that the same concept could be modified and utilized for spinal fixation.

Is there a large learning curve associated with using the ZIP technique?

While there is a requisite training protocol to become familiar with the technology, it is no more difficult than any other new technique which most surgeons are adept at integrating into their respective practices. In fact, it is actually simpler and quicker to perform than existing fusion techniques.

How do you think the ZIP technique could be improved?

I feel it is state of the art and a game-changer for spinal surgery.

Are new discoveries eliminating the need for older spinal treatments?

Yes, the new minimally invasive techniques and implants like the Aurora Zip fusion device are improving outcomes, decreasing time of surgery and decreasing risk.  Patients can be operated on an outpatient basis and sent home the same day or the day following surgery.

To what extent do you think minimally invasive techniques will transform neurosurgery?

They will offer better outcomes, shorter operative times, and shorter recovery times.

What excites you most about the future of spinal fixation techniques?

Improving the quality of patients lives is the most rewarding and exciting aspect of the recent advances in spinal surgery technology. 

Where can readers find more information?

There are extensive surgical educational videos for patients on my web site:

Those interested in more information on the ZIP device can visit:

I have treated numerous patients who have travelled to my offices in Los Angeles from other states and countries. You can learn more about my practice and schedule an appointment or consultation to see if you’re a good candidate for ZIP or other procedures here:

About Ian I.T. Armstrong, M.D., Medical Director, Southern California Spine Institute

A specialist in microsurgery and spinal instrumentation, Dr. Armstrong is the Medical Director of the Southern California Spine Institute, a premier center for the treatment of spinal disorders.

He previously served as the Director of the Spine Program at Century City Hospital, Director of the Spine Program at Midway Hospital, and was a former Chief of Neurosurgery at Century City Hospital. He is an affiliate of the Congress of Neurological Surgeons and the American Medical Association.

Dr. Armstrong has appeared on The Doctors several times, Rescue 911, several national news broadcasts, and has been quoted for his expertise by the Los Angeles Times and the New York Times.

A Diplomate of the American Board of Neurosurgeons, Ian I.T. Armstrong, M.D. specializes in the treatment of cervical and lumbar spine injuries. Dr. Armstrong received his medical degree at Baylor College of Medicine in Houston, Texas, where he was awarded a research fellowship grant on Spinal Cord Trauma from the National Institutes of Health.

After completing his studies, he received further training in Marseilles, France, at the University of Marseilles, Hospital de Conception. He also completed a spine fellowship with neurological and orthopedic training at the University of South Florida.

Dr. Armstrong maintains an active lecture schedule, often speaking to universities, medical professionals, and communities throughout the greater Los Angeles area. He has written and published numerous papers on the topic of spinal disorders and procedures.

Dr. Armstrong is a participating member of the American Association of Neurosurgeons, North American Spine Society, Congress of Neurological Surgeons, and the Los Angeles County Medical Association.

April Cashin-Garbutt

Written by

April Cashin-Garbutt

April graduated with a first-class honours degree in Natural Sciences from Pembroke College, University of Cambridge. During her time as Editor-in-Chief, News-Medical (2012-2017), she kickstarted the content production process and helped to grow the website readership to over 60 million visitors per year. Through interviewing global thought leaders in medicine and life sciences, including Nobel laureates, April developed a passion for neuroscience and now works at the Sainsbury Wellcome Centre for Neural Circuits and Behaviour, located within UCL.


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