Spinal Flexion Tether with Elastic Compliance for L5-S1 Junction
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Solution Overview
Problem
Current spinal implants for inhibiting flexion, particularly at the L5-S1 junction, face challenges in implantation due to anatomical limitations and are not suitable for all patient geometries, leading to limited effectiveness in treating discogenic pain and other spinal conditions like spondylolisthesis.
Innovation Solution
A spinal implant system featuring a tether structure with compliance members that elastically elongate to apply tension between spinous processes and the sacrum during flexion, allowing for non-fixed attachment to spinous processes and fixed or non-fixed attachment to adjacent vertebrae or sacrum, providing resistance to flexion while allowing unrestricted extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spinal implant is designed to inhibit flexion at the L5-S1 junction, then effectiveness in treating discogenic pain is improved, but implantation difficulty increases due to anatomical limitations
Solution Approach 1:
The implant is divided into separate components: a sacral attachment device with bone anchors for fixed attachment to the sacrum, and a spinous process attachment device with straps and compliance members for flexible attachment to the spinous process. This segmentation allows each component to be optimized for its specific attachment site, improving overall implantability at the L5-S1 junction while maintaining treatment effectiveness
Solution Approach 2:
The compliance members are designed with elastic properties that allow dynamic adjustment of restraint force. The straps can be adjusted to different lengths and tension levels, enabling customization of the implant's mechanical parameters to match varying patient anatomies and clinical requirements, thereby facilitating implantation while maintaining therapeutic effect
2Reliability
If a spinal implant uses fixed attachment to spinous processes, then restraint reliability is improved, but adaptability to various patient anatomies deteriorates
Solution Approach 1:
The attachment system transitions from a static fixed connection to a dynamic adjustable system. The straps can be loosened, tightened, or repositioned to accommodate different spinous process sizes and shapes. The compliance members provide dynamic elastic restraint that adapts to the patient's anatomy while maintaining reliable flexion inhibition through adjustable tensioning mechanisms
Solution Approach 2:
The attachment device is designed with universal features that can accommodate various anatomical configurations. The straps can attach to different spinous processes (L4, L5, or S1) depending on patient anatomy, and the compliance members can be configured in different orientations. This multi-functional design allows a single implant system to serve multiple attachment configurations while maintaining reliable restraint
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively restricts spinal flexion, improving treatment outcomes for discogenic pain and spondylolisthesis by accommodating various anatomies and allowing for implantation at the L5-S1 junction, reducing the need for invasive procedures like spinal fusion.
Implementation Method 1
at least a portion of the tether structure is adapted to elastically elongate to apply tension between the spinous process and the adjacent vertebra or sacrum as the spine undergoes flexion
Data Source
AI summary
Spinal implants for limiting flexion of the spine are implanted between a superior spinous process and an inferior spinous process or sacrum. The implants include upper straps which are placed over the upper spinous process, while the lower portions of the implant are attached to the adjacent vertebra or sacrum. The attachments may be fixed, for example using screws or other anchors, or may be non-fixed, for example by placing a loop strap through a hole in the spinous process or sacrum.