PEDICLE SCREWS FOR SPINE FUSION

Spine Fusion Procedure

Spinal fusion permanently connects two or more vertebrae in your spine, eliminating motion between them. Spinal fusion involves techniques to increase healing. The use of pedicle screws improves spinal fusion rates from approximately 60% to 90%. Many surgeons also believe that pedicle screws enhance patient recovery because they provide immediate stability for the spine and early mobilization for the patient.

Initially, the safety and effectiveness of using pedicle screws were brought to the FDA for approval.  Therefore, the FDA studied the use of these screws and approved them for use in the lower (lumbar) spine for specific conditions.

Also, the technique for placing the pedicle screws in the patient requires a steep learning curve. And only surgeons like Dr. Hostin, an experienced surgeon utilizing pedicle screws for decades, should use them.  Importantly, a pedicle screw provides a means of gripping a spinal segment. Further, the screws themselves act as firm anchor points that can then connect with a stabilizing rod.

When considering the placement of pedicle screws in spinal surgeries, there are several critical considerations to ensure safety and efficacy. Firstly, precise planning and imaging are necessary before the procedure to understand individual anatomical variations. This step is crucial to determine the optimal entry point and trajectory of the screws. Additionally, the surgeon must choose the appropriate size and type of screw for each specific spinal level to match the patient’s anatomy, which varies significantly from one individual to another.

Intraoperative guidance, such as fluoroscopy or computer-assisted navigation systems, can be invaluable in minimizing risks. These technologies provide real-time imaging that assists surgeons in placing screws accurately, reducing the likelihood of damaging adjacent structures. Lastly, ongoing training and proficiency in the use of these technologies and techniques are essential for surgeons to maintain high success rates and minimize complications.

Implementation

Surgeons place Pedicle screws with the help of pedicle bone on the back of the spinal column. The screw inserts through the pedicle and into the vertebral body, one on each side. The screws grab into the bone of the vertebral body, and thus, provide a solid hold on the vertebra. In addition, the breakage rate is reduced to about one in 1,000 with modern pedicle screws. Once the doctor places the screws, they attach these screws to metal rods that connect all the screws together. When the doctor bolts together and tightens everything, it will create a stiff metal frame that holds the vertebrae. This process will help in healing. The bone graft gets a place around the back of the vertebrae.

After the bone graft grows, the screws and rods are no longer needed for stability. Also, you can remove it safely through subsequent back surgery. However, most surgeons do not recommend removal unless the pedicle screws cause discomfort for the patient (5% to 10% of cases).

Risks

When a pedicle screw inadvertently punctures the lateral wall of a pedicle, critical nearby structures are at significant risk of injury. This type of mishap can have serious implications depending on the location along the spine where it occurs. In the cervical region, for instance, such an error could threaten the integrity of vital neurovascular components, potentially affecting both nerve and blood vessel functions. In the thoracic region, the stakes are similarly high with the possibility of damaging major vessels such as the aorta. This highlights the need for precise execution in the placement of pedicle screws to avoid such complications.

Research

Subsequently, 350 physicians of the North American Spine Society conducted an analysis of 2,500 patients. These doctors found a very low complication rate using pedicle screws in spinal fusion surgery. Further, information discloses only about a one in 1,000 chance of nerve root damage, and a 2% to 3% chance of infection.

Pedicle screw fixation is a critical technique used in spinal surgeries, but it carries certain risks and complications linked to its application. Detailed studies and research have been conducted to explore these challenges, focusing on the precision of screw placement and potential injuries to nearby structures.

A key piece of research by Gelalis et al. (2012), published in the European Spine Journal, investigates the accuracy of pedicle screw placement. This systematic review compares several techniques, including freehand placement, fluoroscopy guidance, and navigation techniques, exploring their effectiveness and risks. According to the study, incorrect placement can lead to serious complications, such as the puncture of nerves, blood vessels, and muscles surrounding the pedicles. Particularly at risk are the neurovascular structures in the neck when placing cervical pedicle screws and major vessels such as the aorta when dealing with thoracic pedicle screws.

The study suggests that the proficiency of the surgeon and the technique used significantly influence the risk of lateral wall perforation of the pedicle, which may go unnoticed initially or manifest long after the operation. Thus, ensuring meticulous planning and execution during surgery is crucial to minimizing these risks.

This research highlights the complexity and importance of accuracy in pedicle screw fixation in spinal surgeries, underlining the necessity for continuous improvement in surgical techniques and surgeon training.