Polyaxial screw

Polyaxial screw is a type of orthopedic screw used in spinal surgery to secure implants to the vertebrae. It is called "polyaxial" because the head of the screw can rotate in multiple axes, allowing for greater flexibility in attaching the screw to the implant.

Design and Function

The polyaxial screw consists of two main parts: the screw body and the screw head. The screw body is threaded and is inserted into the bone. The screw head is designed to rotate in multiple axes, hence the term "polyaxial". This design allows the surgeon to adjust the angle of the screw head to align with the implant, making it easier to secure the implant to the bone.

The polyaxial screw is typically made of titanium, a strong and lightweight metal that is biocompatible, meaning it is safe to use in the body. The screw is also often coated with a material to promote bone growth and help secure the screw in place.

Applications

Polyaxial screws are primarily used in spinal surgery, particularly in procedures to correct spinal deformities such as scoliosis and kyphosis. They are also used in spinal fusion surgery, a procedure in which two or more vertebrae are fused together to stabilize the spine and relieve pain.

In these procedures, the polyaxial screws are inserted into the vertebrae and then attached to a rod or plate that is used to stabilize the spine. The ability of the screw head to rotate in multiple axes allows the surgeon to adjust the position of the screw to best fit the anatomy of the patient's spine.

Advantages and Disadvantages

The main advantage of polyaxial screws is their flexibility. The ability of the screw head to rotate in multiple axes allows the surgeon to adjust the position of the screw to best fit the anatomy of the patient's spine. This can make the surgery less invasive and reduce the risk of complications.

However, polyaxial screws also have some disadvantages. They can be more difficult to insert than other types of screws, and there is a risk that the screw head could loosen over time. In addition, while the polyaxial design allows for greater flexibility, it also means that the screw is not as stable as a monaxial screw, which could potentially lead to instability in the spine.

See Also

• Orthopedic surgery
• Spinal fusion
• Scoliosis
• Kyphosis

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