Beyond the pedicle screw-a patent review

Area of Science:

• Spinal Surgery
• Biomedical Engineering
• Orthopedic Devices

Background:

• Conventional pedicle screws are standard for spinal fusion but may lack fixation strength, especially in osteoporotic bone.
• An aging population requires bone anchors with improved fixation strength, safe placement, and tissue-sparing removal.
• Patent literature review focuses on intrapedicular bone anchors to address these limitations.

Purpose of the Study:

• To provide an overview of the patent literature on posteriorly placed intrapedicular bone anchors.
• To identify and categorize novel anchoring methods for spinal fixation.
• To assess the potential of these anchors for improving fixation strength and patient outcomes.

Main Methods:

• Patent search conducted in the Espacenet database using specific Cooperative Patent Classification codes (A61B17/70, A61B17/7001).
• Inclusion criteria focused on patents for spinal positioners and stabilizers.
• 56 unique patents on anchoring methods were reviewed and categorized.

Main Results:

• Five distinct fixation methods were identified: threading, curved path, expansion, cement augmentation, and bone ingrowth initiation.
• Eight anchor designs had a corresponding commercial product.
• Six of these commercial anchors have been evaluated in clinical trials.

Conclusions:

• Patented intrapedicular bone anchors offer increased fixation strength compared to conventional pedicle screws.
• Identified anchoring methods can inform clinical decision-making.
• These findings serve as inspiration for the design of novel bone anchors.