A pedicle screw system is a set of surgical implants used to stabilize two or more vertebrae while bone fusion takes place. Surgeons rely on this type of spinal instrumentation in cases of degenerative disc disease, spinal deformity, trauma, and certain tumor-related instabilities. Understanding how a pedicle screw system works helps patients and referring clinicians alike make sense of what happens during a fusion procedure and why these implants remain a standard tool in modern spine surgery.
What Does a Pedicle Screw System Actually Do?
The pedicle is the strongest anatomical corridor into a vertebral body, which is why screws are placed through it rather than into softer bone elsewhere in the spine. Once a screw is anchored in the pedicle, it acts as a fixed point that can be connected to adjacent vertebral levels using a rod. This rod-and-screw framework holds the targeted spinal segment in a controlled position, limiting motion so that bone graft material placed between vertebrae has a stable environment in which to fuse. Without this temporary internal stabilization, the natural movement of the spine could disrupt the healing process and prevent solid fusion from forming.
Why Are Polyaxial Screws Used So Often?
Polyaxial screws are designed with a screw head that can pivot within a range of angles relative to the screw shaft, rather than being fixed in a single orientation. This design gives the surgical team flexibility when connecting screws across multiple vertebral levels, since the spine's natural curves and each patient's unique anatomy rarely allow for perfectly aligned screw placement. A polyaxial mechanism allows the rod to seat properly into each screw head even when the trajectories are not identical, reducing stress on the construct and simplifying the technical steps of rod placement. This adaptability is one of the main reasons polyaxial designs are common across contemporary spinal instrumentation.
How Rod Constructs Complete the Fixation
The rod is the structural element that ties individual pedicle screws together into a single working unit, commonly called a rod construct. Rods are generally manufactured from titanium or cobalt-chromium alloys chosen for strength and long-term compatibility with the body. Depending on the clinical goal, a construct may span a single motion segment or extend across several vertebrae for more complex deformity correction. Locking mechanisms in the screw head secure the rod in place, and the entire assembly is checked intraoperatively for alignment before the incision is closed.
SpineNav MIS Pedicle Screw System
Among the polyaxial pedicle screw systems used in minimally invasive spinal fixation is the SpineNav MIS Pedicle Screw System, part of INVAMED's neuro-spine-cranial product line. As described in company technical materials, SpineNav is a polyaxial system built for MIS (minimally invasive surgery) applications, allowing screws to be placed through smaller access corridors while still forming a complete rod construct. Readers interested in the broader range of spinal fixation and cranial devices can review the full neuro-spine-cranial product category.
How long does a pedicle screw system stay in the body?
In most cases, pedicle screws and rods are intended to remain permanently once solid bone fusion has occurred, since removal is generally unnecessary unless a specific complication arises. A qualified physician determines whether hardware removal is appropriate on an individual basis. Long-term outcomes vary by patient anatomy, bone quality, and the extent of the original spinal condition.
Is a pedicle screw system the same as a spinal fusion?
No. The pedicle screw system is the instrumentation that stabilizes the spine, while fusion is the biological process of bone growth that permanently joins the treated vertebrae. The screws and rods hold the segment still so that fusion, which typically involves bone graft material, can proceed without excessive motion interfering with healing.
Are pedicle screws visible on imaging after surgery?
Yes, pedicle screws and rods are radiopaque and are routinely visualized on X-ray, CT, and in many cases MRI, which allows surgeons to confirm placement and monitor healing over time. Imaging follow-up schedules are determined by the treating surgical team based on individual recovery.
Device availability and regulatory status vary by country. Please contact INVAMED or your authorized local distributor for current regulatory information applicable to your region.