lumbar surgery

Pedicle Screw Placement in Lumbar Spinal Surgeries

Spinal conditions affecting the lower back may be resolved with lumbar spine surgery. When non-invasive treatment options fail, spinal surgery can relieve nerve compression and diminish persistent symptoms, such as weakness, tingling, and chronic back pain. 

To prevent spinal instability after surgery, surgeons typically perform spinal fusion or use spinal implants, such as the TOPS System. In these stabilizing procedures, surgeons use pedicle screws to grasp spinal segments and regulate spinal motion. 

Continue reading to learn more about the role of pedicle screw placement in lumbar spine surgery to heal conditions including spinal stenosis and spondylolisthesis. 

How Are Pedicle Screws Used in Lumbar Spine Surgery?

In spinal fusion, pedicle screws are positioned around the affected vertebrae. Specifically, the screws are fixed onto the pedicles of two consecutive intervertebral segments.

The lumbar spine includes five different segments, L1 through L5. So, for example, pedicle screws may be situated on segments L3 and L4. 

Lumbar Procedures That Involve The Use of Pedicle Screws

Spinal fusion and dynamic stabilization are surgical procedures often used to resolve instability in the lumbar spine. Both of these procedures involve the use of pedicle screws. 

In spinal fusion, the main function of pedicle screws is to prevent movement in the affected vertebrae while the fused vertebrae heal. The pedicle screws bear stress from daily motions and activities as the vertebrae fuse into a single bone. 

Pedicle screws are also used for stability in dynamic stabilization, although the affected vertebrae aren’t fused together. Instead, a spinal implant is attached to the vertebrae for strength and support. 

What Are Pedicles?

Pedicles are small pieces of hard bone that protrude from the back of a vertebra. Each vertebra in the spine has two pedicles, each of which has a cylindrical shape. 

There are two main functions of a pedicle:

1. To protect the side of the spinal nerves and the spinal cord
2. To connect the front and back of the vertebra for stability and spinal function

Pedicle Screws in Spinal Fusion vs. Dynamic Stabilization

Overview of Spinal Fusion

Fusion is commonly performed in conjunction with spinal decompression surgery to prevent instability. Since decompression surgery can cause abnormal motion between the affected vertebrae, fusion may be required for strength and stability.

Spinal fusion can also prevent re-injury from spinal instability and weakness after lumbar spine surgery.  

The Steps of Spinal Fusion

During spinal fusion, the surgeon first makes an incision to access the lumbar spine. Once the surgeon has access to the spine, they can remove tissue that’s causing nerve compression and pain. 

Next, the surgeon places a bone graft in between the two affected vertebrae. This graft may come from an outside source or be taken from the patient’s own bone tissue. Over time after the procedure, the bone graft will heal and fuse the vertebrae into a single bone. 

After the bone graft has been placed, your surgeon may insert metal plates, pedicle screws, and rods around the affected vertebrae to keep them from moving during the recovery process. 

Overview of Dynamic Stabilization

Dynamic stabilization is widely viewed as an alternative to spinal fusion. It involves the use of spinal implants to stabilize the spine without fusion. Pedicle screws are often used with spinal implants to keep the implant secured to the vertebrae. 

Whether for patients with a disorder that causes instability, like spondylolisthesis, or instability triggered by spinal surgery, dynamic stabilization can prevent pain and injury to the spine. 

The Steps of Dynamic Stabilization

Similar to spinal fusion, dynamic stabilization begins by accessing the spine. If the goal of surgery is to resolve nerve compression, some spinal tissue is removed. 

Next, your surgeon will position a spinal implant, like the TOPS System, to support the affected vertebrae. Pedicle screws are commonly used to fasten the implant in place. 

Comparing Spinal Fusion and Dynamic Stabilization

In comparing spinal fusion and dynamic stabilization, there are several factors to consider:

• Spinal range of motion

By fusing the affected vertebrae into a single bone, spinal fusion limits the movement of the spine. On the other hand, dynamic stabilization controls spinal movement to prevent injury without reducing the patient’s range of motion. 

With the TOPS System, patients can comfortably bend and flex the spine after surgery. This is in contrast to patients after spinal fusion, who often can’t bend down to pick objects off of the floor. 

• Spinal load sharing

Compared to spinal fusion, dynamic stabilization with the TOPS spinal implant system can reduce the load on pedicle screws. This allows the implant system and the vertebrae to bear the impact on the spine evenly.

By promoting even distribution of impact, the TOPS System prevents the pedicle screws from loosening over time. This is a significant benefit, given that loosened pedicle screws often require additional spinal surgery.  

• Adjacent segment degeneration

Adjacent segment degeneration (ASD) is a condition that many patients get after spinal fusion. This condition results from an increased impact on the parts of the spine surrounding the fused vertebrae. 

By helping to evenly distribute impact across the spine, dynamic stabilization can prevent the pain and complications associated with ASD. 

Pedicle Screw Options

Not all pedicle screws are made equally. Pedicle screws can differ in design, construction, and processing. 

The ProMIS System is a unique pedicle screw that can provide singular benefits for patients undergoing lumbar spine surgery. These benefits include:

• A patented screw surface

The surface of these pedicle screws undergoes a patented treatment approach involving calcium phosphate. This creates a rough screw surface to prevent loosening over time. 

• Sterile double-blister packaging

Reprocessing can lead to contamination, implant damage, and related issues in pedicle screws. ProMIS System pedicle screws are sent in sterile double-blister packaging to prevent contamination and infection. 

• Constant shaft diameter and conical shape

The specialized design of the pedicle screws from the ProMIS System allows for optimal screw fixation and, therefore, long-term implant stability. 

To learn more about the TOPS and ProMIS systems for lumbar spine surgery, contact Premia Spine today.