Monday, November 4, 2013

The O-arm

By: Joseph G. Khoury, M.D., Chief of Pediatric Orthopedics at Children’s of Alabama and an Assistant Professor of Pediatric Orthopedics at UAB
The orthopedic surgeons here at Children’s of Alabama have taken the next step toward safe and efficient scoliosis care with the incorporation of new technology called the “O-arm” (from Medtronic and Stealth Navigation) for use in all scoliosis surgery. We began using this technology this past summer, and now regard this product as an indispensable tool that we wonder how we ever got along without.
The O-arm is a portable, intra-operative CT scanner. The device looks like three-quarters of a circle and moves in over the patient after the spine has been exposed.  A reference frame is secured to a spinous process just below or above where we plan to work. The O-arm closes in to form a complete circle around the patient.  Then, the “spin” occurs. The spin is basically a CT scan taken in the prone position with the spine exposed. The radiation dose is approximately one-third of a regular CT.
The data from the spin with respect to the reference frame is then assimilated so we can navigate with special instruments and create pathways for our pedicle screws while watching in three dimensions on a monitor with live feedback in order to avoid injury to the delicate surrounding neurovascular structures.
This technology has allowed us to place spinal instrumentation in places where it was previously not possible with standard two dimensional imaging. In addition, the implants are placed more rapidly and we can be confident that they are placed into a completely safe position. While the incidence of neurologic injury from misplaced implants is relatively low, the incidence of misplaced hardware is alarmingly high. We certainly feel much more comfortable knowing exactly where every implant is located.
After using the O-arm in several cases, we have found the most efficient way to incorporate the use of the O-arm into our cases and there is no longer any delay or increase in case time. In fact, for more difficult cases and more severe curves, the case time is decreased. This means less blood loss and lower risk of infection for severe degrees of curvature.
Scoliosis is only the beginning. Many other centers utilize the O-arm for complicated peri-acetabular osteotomies, to optimize the placement of screws for slipped capital femoral epiphysis or to confirm the complete removal of a subtalar coalition.  The opportunities to use the O-arm to enhance the precision of surgery performed at Children’s are virtually limitless and we feel strongly that our patients will benefit from this new technology.
Joseph G. Khoury, M.D., is Chief of Pediatric Orthopedics at Children’s of Alabama and an Assistant Professor of Pediatric Orthopedics at UAB. He earned his medical degree at the University of Iowa College of Medicine, completed his internship and residency at the University of Iowa Hospitals and Clinics and his Fellowship at Children's Orthopedics of Atlanta.
You can reach me at 205-638-9540 for more information.

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