Composite Bone Implants for Minimally Invasive Sacroiliac Fixation
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Solution Overview
Problem
Current methods for sacroiliac joint fusion and spinal fixation require large incisions and extensive soft tissue stripping, leading to prolonged recovery times and potential complications.
Innovation Solution
A composite bone implant with a distal anchoring region and growth region, featuring an inner shank and outer sleeve designed for minimally invasive insertion through the iliac bone, allowing for bony on-growth, in-growth, and through-growth, and resistance to relative motion, which can be used to stabilize and fuse bones using a lateral or posterolateral approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional screws and plates are used for sacroiliac fusion, then the joint can be stabilized, but large incisions and extensive soft tissue stripping are required
Solution Approach 1:
The implant is divided into two separate components: an inner shank that anchors into the sacrum and an outer sleeve that anchors into the ilium. These segmented components are inserted through separate minimally invasive trajectories, avoiding the need for large incisions and extensive soft tissue stripping while still achieving reliable sacroiliac joint stabilization.
Solution Approach 2:
The inner shank is nested within the outer sleeve, with the sleeve positioned over at least a portion of the shank. This nested configuration allows both components to be implanted through minimally invasive approaches while maintaining structural integrity and achieving reliable joint fixation without large incisions.
2Stability of the object's composition
If long constructs with rods are used to join and fuse vertebrae, then spinal stability is improved, but the complexity of the implant system increases
Solution Approach 1:
The composite implant combines multiple functions into a single integrated system: the inner shank provides sacral anchoring with threads for bone engagement, the outer sleeve provides iliac anchoring with growth features for bony on-growth and in-growth, and the interface between them resists relative motion. This multi-functional design achieves spinal stability without requiring separate rods and multiple components, thereby reducing overall system complexity.
Solution Approach 2:
The implant merges the anchoring functions for both the sacrum and ilium into a single composite structure, eliminating the need for separate long constructs and rods. The combined inner shank and outer sleeve system provides comprehensive spinal stabilization while reducing the number of individual components and simplifying the implantation procedure.
3Strength
If the inner shank and outer sleeve are designed to resist relative motion, then fixation strength is improved, but the complexity of the interface features increases
Solution Approach 1:
The interface between the inner shank and outer sleeve employs localized engagement features positioned at specific locations along the components. Rather than complex features throughout the entire interface, localized quality features are strategically placed to provide sufficient resistance to relative motion and achieve strong fixation while maintaining simplicity in the overall design.
Data Source
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Figure 2A~2C
Figure 2D
AI summary
Bone implants, including methods of use and assembly. The bone implants, which are optionally composite implants, generally include a distal anchoring region and a growth region that is proximal to the distal anchoring region. The distal anchoring region can have one or more distal surface features that adapt the distal anchoring region for anchoring into iliac bone. The growth region can have one or more growth features that adapt the growth region to facilitate at least one of bony on-growth, in-growth, or through-growth. The implants may be positioned along a posterior sacral alar-iliac ("SAI") trajectory. The implants may be coupled to one or more bone stabilizing constructs, such as rod elements thereof.