Posterior Dynamic Stabilization System for Spinal Kyphosis Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current surgical methods for cervical spondylotic myelopathy, such as laminectomy and fusion, often result in post-laminectomy kyphosis, instability, and accelerated spondylotic changes, with no effective motion-sparing solutions available to reconstitute the posterior tension band following decompression.
Innovation Solution
A posterior dynamic stabilization system that includes elastically deformable and rigid bias elements to provide semi-constrained motion between spinal segments, preserving normal mobility and preventing kyphosis, while allowing correction of pre-existing deformities through the use of bridge elements and anchoring members secured to the vertebrae.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If laminectomy is performed to decompress the spinal cord, then neural decompression is achieved, but post-laminectomy kyphosis and instability develop due to loss of the posterior tension band
Solution Approach 1:
The patent introduces a posterior tension band reconstruction system that acts as an intermediary structure to replace the removed posterior elements. The system includes spinous process implants with ligamentous constructs that bridge the gap created by laminectomy, restoring the tension band function without requiring fusion of the vertebral bodies. This mediator approach allows decompression while maintaining spinal stability.
Solution Approach 2:
The invention segments the stabilization function into separate components: spinous process implants, ligamentous constructs, and optional rod connections. Rather than fusing the entire spinal segment, only the posterior elements are reconstructed independently, preserving anterior and middle column mobility while addressing the specific instability caused by laminectomy.
2Stability of the object's composition
If multi-level fusion is performed to prevent kyphosis, then spinal stability is improved, but range of motion is significantly lost and adjacent segment degeneration accelerates
Solution Approach 1:
The patent applies stabilization locally to the posterior tension band rather than globally fusing the entire spinal motion segment. The spinous process implants and ligamentous constructs are positioned specifically to restore posterior tension only, leaving the anterior and middle columns free to maintain normal range of motion. This localized approach prevents kyphosis without sacrificing mobility.
Solution Approach 2:
The invention uses dynamic, non-rigid ligamentous constructs and flexible rod connections that allow controlled motion between vertebral levels. The system provides stability when needed (preventing kyphosis) while permitting physiological range of motion during normal spinal movement, adapting to the dynamic needs of the spinal column rather than imposing rigid fixation.
3Ease of operation
If laminoplasty is performed to preserve spinal motion, then range of motion is maintained, but the procedure is not indicated in the setting of preoperative cervical straightening or kyphosis
Solution Approach 1:
The patent performs preliminary reconstruction of the posterior tension band using spinous process implants and ligamentous constructs before addressing the alignment issue. By first restoring the posterior stabilizing structures, the system creates a stable foundation that can then support correction of pre-existing kyphosis or straightening, making the procedure applicable to a broader range of spinal alignments than traditional laminoplasty.
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 reconstitutes the posterior tension band, preventing post-operative kyphosis and maintaining spinal mobility, thereby addressing the limitations of existing surgical methods by allowing semi-constrained motion and balance control.
Implementation Method 1
at least one bias element is elastically deformable and attached at one end to a first bridge element and at another end to a second bridge element to provide a restoring force
Data Source
AI summary
A system for providing dynamic stabilization and balance control at a vertebral motion segment has first and second bridge elements and at least one bias element. The bridge elements anchor to adjacent vertebrae with polyaxially adjustable anchoring members, and the bias elements attach to each bridge element to span between them. Each bias element has two fixation portions and a bias body extending between the fixation portions. Each bias element may comprise an elastically deformable material to provide dynamic stabilization with motion, or may comprise rigid material to provide rigid stabilization, and both bias element types may be included in one system. The bias elements are attachable to the bridge elements at discrete attachment locations, or at non-discrete attachment locations. Alternate embodiments may include three or more bridge elements on adjacent vertebrae, and multiple bias elements. A tensioning tool may provide adjustable tension to an elastically deformable bias element.