Cervical Midline Fixation via Trans-Lamina Delivery
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Solution Overview
Problem
Current spinal fixation procedures in cervical stabilization are challenging due to the complexity of the cervical spine anatomy, which poses risks of trauma and injury from muscle stripping, tissue damage, and the limited bone mass and density, requiring improved methods for securely positioning fixation assemblies while minimizing trauma.
Innovation Solution
The use of trans-lamina delivery and occipital plates with floating nuts and angled anchor-receiving openings allows for secure positioning of spinal fixation elements along the midline of the spine, reducing the risk of trauma and enabling more stable fixation by angling the delivery trajectory away from the spinal canal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lateral mass anchoring devices are used for cervical fixation, then the fixation elements can be attached to adjacent vertebrae, but significant muscle stripping and tissue damage occur due to the distance between the lateral mass entry point and the midline of the spinal column
Solution Approach 1:
Instead of approaching the spinal column from the lateral mass (lateral to midline trajectory), the invention inverts the approach by delivering fixation elements through the lamina from a midline or paramidline position. This reverse trajectory eliminates the need for extensive lateral muscle stripping while maintaining secure vertebral engagement through the lamina and into the vertebral body.
Solution Approach 2:
The invention introduces the lamina as an intermediary structure for delivering fixation elements. Rather than directly anchoring from the lateral mass to the midline, the fixation elements are delivered through the lamina (which is more accessible and has sufficient bone stock) to reach the vertebral body, thereby avoiding direct trauma to the lateral muscles and soft tissues.
2Reliability
If traditional lateral mass anchoring is performed, then fixation elements can be secured to vertebrae, but the limited bone mass and density in the lateral mass significantly limits the ability to effectively engage anchoring devices
Solution Approach 1:
The lamina serves as an intermediary delivery path that provides access to the vertebral body without requiring engagement of the limited lateral mass bone. The fixation elements traverse the lamina (which has adequate bone stock) to reach the denser vertebral body, thereby achieving secure anchoring while bypassing the bone density limitations of the lateral mass.
Solution Approach 2:
The invention changes the anatomical parameters of the delivery trajectory by moving from a lateral approach (through lateral mass) to a midline approach (through lamina). This parameter change in delivery location allows access to vertebrae with greater bone mass and density, improving anchoring engagement while avoiding the bone quality limitations of the lateral mass region.
3Reliability
If traditional anchoring device delivery is used in cervical spine, then fixation can be achieved, but slight miscalculation in delivery trajectory can result in penetration of the anchoring device into the spinal canal, causing significant injury
Solution Approach 1:
The invention inverts the delivery trajectory by approaching from the midline through the lamina rather than from the lateral aspect. This reversed approach naturally directs fixation elements away from the spinal canal (which lies anterior to the midline), thereby eliminating the risk of canal penetration that exists with lateral approaches where the spinal canal is in close proximity to the delivery path.
Solution Approach 2:
The lamina acts as a protective intermediary structure during device delivery. By delivering fixation elements through the lamina, the spinal canal is shielded from direct exposure to the delivery trajectory and anchoring device, thereby preventing inadvertent penetration and injury to neural structures within the canal.
4Reliability
If occipital plate fixation is performed in cervical spine, then stabilization can be achieved, but the anatomy of the cervical spine makes it a technically difficult area to instrument due to vital neural and vascular structures
Solution Approach 1:
The lamina serves as an intermediary surgical corridor that provides safe access to the vertebral body and fixation targets. By utilizing the lamina as the delivery path, surgeons can navigate around vital neural and vascular structures (such as the vertebral arteries and spinal cord) while still achieving secure fixation, thereby reducing surgical complexity and risk.
Solution Approach 2:
The invention changes the surgical dimension by moving from a lateral approach (requiring navigation near vertebral arteries and neural foramina) to a midline approach through the lamina. This dimensional shift in access trajectory provides a safer surgical corridor that avoids critical neurovascular structures while maintaining the ability to achieve stable occipitocervical fixation.
Data Source
AI summary
Devices and methods for enhancing the effectiveness of spinal stabilization, and particularly that of cervical spinal stabilization, are provided herein. More specifically, methods and systems are disclosed for effectively positioning occipital plates and spinal fixation assemblies within target vertebrae, while also reducing any associated patient trauma (e.g., muscle stripping, tissue damage, etc.). The systems and methods can utilize trans-lamina delivery of the spinal fixation assemblies to allow for the positioning of the fixation elements along the midline of the patient's spine.