Spinal surgery is one of the most delicate operations there is.

Accuracy is critical, but even in the hands of the most skilled surgeons, screws can be misplaced up to 40-percent of the time.

But now, doctors are pioneering a new procedure that takes away the guesswork.

Imagine a global positioning system that works inside the human body. Surgeons say they are now able to achieve the same kind of pinpoint accuracy for back patients.

Thirty-two-year-old Chantai Adams had a spinal fusion to relieve the pain. Doctors used tiny surgical screws and hardware to link a portion of her vertebrae together, eliminating any movement.

It's a very common procedure, but one that doctors admit is not always perfect.

"In an ideal world, where you're doing day-to-day surgery, your misplacement rate is probably in the order of 10-percent," explains Dr. Richard Spiro, a neurosurgeon at the University of Pittsburgh Medical Center.

In very complicated cases, experts say surgical screws can be misplaced up to 40-percent of the time. Dr. Spiro is pioneering a procedure that guides the screw placement.

Doctors take a scan of the spine, creating a 3D image. Cameras in the operating room communicate with transmitters on the tips of surgical tools. A computer monitors the movement.

"Then we're able to place the hardware based on that real-time information, just like a GPS gives you when you're trying to make decisions about whether to turn right or turn left. We're doing the same thing," Dr. Spiro explains.

With this system, doctors say they are accurate within one millimeter, meaning fewer complications for patients -- and for some, a faster recovery.

After more than 100 surgeries, Dr. Spiro says surgeons using the system have a perfect accuracy rate.

MEDICAL BREAKTHROUGHS RESEARCH SUMMARY
TOPIC: GPS FOR THE SPINE
REPORT: MB #2976

BACKGROUND:

According to the American Association of Neurological Surgeons, 75 to 85 percent of Americans will suffer some form of back pain during their lives. Ninety percent of back pain cases improve without surgery, but for those who aren't as fortunate, a procedure called spinal fusion may be necessary.

According to the American Journal of Neuroradiology, lumbar spinal fusion procedures were first used to treat individuals with misaligned spines or infections in the spine, but are increasingly performed to treat degenerative disc disease and disc pain syndromes.

The procedure usually involves cleaning out the existing disc between two vertebrae and replacing it with bone graft material. Wires, rods or screws are often used to stabilize the area.

The surgery eliminates motion between vertebrae segments, alleviating pain caused by motion. The procedure is also used to stop the progress of spinal deformities such as scoliosis. Spinal fusion takes away some of the patient's flexibility.

Typically, the procedure can be used to treat the following:

- Spine vertebrae injuries
- Disc degeneration between vertebrae
- Abnormal curvatures
- Weak or unstable spines caused by infections or tumors

NAVIGATING THE SPINE WITH GPS:

Surgeons are now using image-guided spinal navigation, similar to global positioning systems, or GPS, to navigate the spine during spinal fusion surgery.

A special camera on a computer uses infrared light to track a surgical instrument in real time while it's placed on a patient's spine, providing a 3-D image of a patient's anatomy. Using the computer, the surgeon navigates the spine and determines the best entry point and trajectory for each screw. An image-guided screwdriver is used to place screws.

The new technology is superior to conventional imaging devices like fluoroscopy. Experts say it improves the speed, accuracy and precision of complex spinal surgery.

The system accurately places screws within one millimeter. In a study published in the Journal of Neurosurgery: Spine, involving placing 1,084 "pedicle" screws in 220 patients, less than 1 percent of the screws were considered to be significantly misplaced.

In addition, surgeons reported a nerve injury rate of less than 1 percent. The injury rate for standard technology is up to 8 percent and misplacement is up to 55 percent.

"In addition to the decreased incidence of nerve root injury, this technology allows us to place larger screws into the spine, which can also increase the success rate of the operation," Eric Nottmeier, M.D., the study's lead investigator and a neurosurgeon at the Mayo Clinic in Jacksonville, Fla., was quoted as saying.