Background
Scoliosis and other forms of spinal deformity have traditionally been conceptualized in two dimensions, similar to how a patient is viewed when looking at an x-ray. The logical approach to correction of the curve would be to apply a pure distraction force to the spine to make it straight. Prior to the development of spinal instrumentation (rods), this correction could be achieved only by aggressively correcting the spine in a tight-fitting cast and performing a spinal fusion to hold it straight. The earliest spinal instrumentation (Harrington Rods), provided surgeons with a new way to apply a more powerful corrective force to the spine. Harrington Rods used primarily distraction forces for correction of spinal curves. This greatly decreased the amount of time that patients had to be immobile after surgery. However, the pure distraction force created by Harrington rods made the back flat, causing many patients to have lower back pain later in life.

In the late 1970's, spinal surgeons began to think about spinal deformity in three dimensions. Realizing that most scoliosis is a 3-dimensional deformity, surgeons sought ways to restore the normal contours to the spine during correction of the spinal deformity. The development of dual rod spinal instrumentation systems allowed surgeons to correct the spinal deformity and restore the normal contour to the back using multiple points of fixation to the spine. Dual rod segmental fixation theoretically allowed surgeons to "de-rotate" the spine and improve the overall cosmetic appearance of the back.

There is considerable controversy whether the 3-dimensional correction of the deformity is the result of distraction, rotation or translation of the spine into the corrected position. The answer is that it is probably a combination of these that results in correction of the deformity. Pure distraction is capable of producing correction in the coronal (frontal) plane but tends to make the back flat in the process. Translation force can "pull" the spine at a point where the deformity is the greatest and produce powerful corrective forces. The use of rotational forces is a way to restore a more normal alignment of the spine in the saggital (side) plane while addressing the fact that the vertebrae are rotated as part of the curve. Understanding these differences is important when considering that the COLORADO 2™ System uses a combination of these forces to correct spinal deformity.

Technology First
The majority of current spinal instrumentation systems consist of rigid points of attachment between the spine and the rods used for correction. Forceful maneuvers are often needed to attach the rod to the hook or screw implant during implantation to obtain correction of the deformity. Excessive force at the spine-implant interface may be strong enough to cause the bone to fail or the hook to displace during correction.

There are several unique features of the COLORADO 2™ Spinal System that address these problems. First, the rods are made of a special stainless steel alloy that provides high mechanical strength and fatigue resistance while maintaining flexibility. Second, there is 34 degrees of variability when the rod and clamp are connected to the spinal implant. The combination of rod flexibility and rod-clamp variability allows the surgeon to attach the spine to the rod at multiple points before applying the corrective force to the deformity. This lessens the risk of failure at the spine-implant interface during the correction. Third, the combination of stable pedicle screws and pedicle hooks secured with a unique staple creates stable points of fixation for correction.

Surgeons can take advantage of the combination of stable fixation points and the variability of the implant/clamp interface to achieve a gradual three-dimensional correction of spinal deformity. Once the rod is loosely attached to the implants at multiple points along the deformity, the surgeon simply tightens the attachment nuts that secure the implant to the rod. As the nuts are sequentially tightened, the implants realign the spine to the previously contoured rod and the spinal deformity is corrected.

The COLORADO 2™ Spinal System comes with innovative and ergonomically designed instruments that further improving the process of placement of spinal instrumentation.