Segmental Bone Scaffold Using Degradable Polymer and Collagen
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Solution Overview
Problem
Current treatments for segmental long bone defects often result in morbidity, complications, and the need for amputation, with limited options for permanent bone regrowth without external fixation or significant healing challenges.
Innovation Solution
A polymer scaffold design featuring a degradable outer shell with a collagen-containing material, designed to fit over a segmental bone defect, providing structural support and facilitating bone regrowth without amputation, using degradable poly(urethane) or poly(ester urea) polymers and a collagen-containing material like decellularized horse tendon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current treatment strategies (autologous bone graft, free vascularized bone graft, synthetic bone graft substitutes) are used for segmental long bone defects, then bone repair is attempted, but high rates of infection, delayed union, non-union, and amputation occur
Solution Approach 1:
The scaffold is divided into modular segments that can be assembled to match the specific defect geometry. Each segment contains bone marrow substitute material separated by spacers, creating a segmented structure that promotes organized bone regeneration while reducing infection risk through compartmentalization
Solution Approach 2:
The scaffold acts as an intermediary device between the bone defect and the regenerative process. It provides a temporary structural framework that mediates bone growth, delivers growth factors, and protects the regeneration site from infection until natural bone healing occurs
2Adaptability or versatility
If limb salvage is attempted for segmental long bone defects exceeding 10-30 cm, then amputation is avoided, but significant challenges including high rates of infection, delayed union, and non-union occur
Solution Approach 1:
The scaffold provides localized structural support and biological activity exactly where needed in the bone defect. The bone marrow substitute material is delivered locally to the defect site, and the scaffold's mechanical properties are optimized for the specific load-bearing requirements of that location, improving healing reliability without amputation
Solution Approach 2:
The scaffold combines synthetic polymer materials with natural bone marrow substitute materials to create a composite structure. This composite approach integrates the mechanical strength and durability of synthetics with the osteoinductive properties of natural materials, enabling reliable limb salvage for large defects
3Ease of manufacture
If primary amputation is performed for segmental long bone defects, then immediate removal of non-functional limb is achieved, but patient is permanently disabled and at increased risk for becoming destitute, divorced, or depressed
Solution Approach 1:
The scaffold is pre-loaded with bone marrow substitute material and growth factors before implantation. This preliminary preparation ensures that the regenerative process is immediately initiated upon implantation, making limb salvage as straightforward as amputation while avoiding permanent disability
4Reliability
If a polymer scaffold with degradable outer shell and collagen-containing material is used, then permanent bone regrowth is enabled, but device complexity increases compared to current systems
Solution Approach 1:
The scaffold utilizes controlled degradation of the outer shell polymer over time, changing its mechanical properties from rigid to flexible as it breaks down. This parameter change allows the scaffold to provide initial structural support then gradually transfer load to the regenerating bone, enabling permanent bone regrowth without overly complex design
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 polymer scaffold enables permanent bone regrowth in segmental defects, reducing morbidity and the need for amputation by providing structural support and promoting bone healing, as demonstrated by successful animal tests showing significant bone regeneration and functional recovery.
Implementation Method 1
The outer shell and insert are made from degradable polymer material
Implementation Method 2
collagen-containing material like decellularized horse tendon
Data Source
AI summary
The present invention relates to a polymer scaffold design and method for treating segmental long bone defects without amputation that permits permanent regrowth of bone in the area of the segmental defect, without external fixation or other problems inherent in current systems. The polymer scaffold is preferably made from a poly(ester urea) polymer and includes an outer shell, sized to fit over a segmental defect in a bone, and a collagen containing material. In some embodiments, the collagen containing material is placed in a polymer insert sized to fit within the segmental bone defect and within said outer shell. In some embodiments, the outer shell may contain struts running longitudinal struts along the inside surface of the outer shell. In some of these embodiments, the insert will have a corresponding set of grooves sized to receive the struts.