Patient-Specific Mega Spacer for Severe Bone Loss Reconstruction
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Solution Overview
Problem
Current joint replacement surgeries face challenges in selecting the appropriate size and shape of implants for bone reconstruction, particularly in cases of severe bone loss or tumors, leading to limited patient mobility and high costs due to the use of traditional, non-customized temporary prostheses.
Innovation Solution
A patient-specific mega spacer designed using CT scans and 3D printing technology, made from medical-grade Nylon PA2200, which allows for antibiotic delivery and extended implantation period, enabling longer mobility and reduced recovery time before permanent implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional standard instruments and implants are used for joint replacement surgery, then the surgical procedure is straightforward, but the implant cannot match the specific dimensions and anatomical shape of the patient's bone, especially in cases of severe bone loss or tumors
Solution Approach 1:
The patent applies local quality by creating patient-specific implants that are customized to match the unique anatomical shape and dimensions of each patient's bone structure. The implants are designed with specific geometries that correspond to the local characteristics of the damaged bone, ensuring optimal fit and function rather than using standardized one-size-fits-all components.
Solution Approach 2:
The patent employs preliminary action by performing pre-surgical planning and design using CT scan data and specialized software to create a three-dimensional model of the patient's anatomy before the actual surgery. This allows the custom implant to be manufactured in advance with precise anatomical matching, eliminating the need for intraoperative adjustments.
2Reliability
If medical cement is used to form a temporary spacer, then the space can be maintained in damaged bone, but the patient is forced to stay in bed with limited activities for up to three months
Solution Approach 1:
The patent applies parameter changes by transitioning from traditional medical cement spacers to rigid, load-bearing polyethylene spacer implants. This material parameter change enables the temporary implant to withstand physiological loads and allow patient mobility while maintaining the necessary space for soft tissue tension and subsequent permanent implantation.
Solution Approach 2:
The patent employs this principle by designing a temporary spacer implant that serves its purpose for a limited duration (typically 6-12 weeks) before being replaced by a permanent prosthesis. The spacer is intentionally designed as a temporary, disposable component that maintains space and soft tissue tension during the healing period without requiring long-term durability.
3Ease of manufacture
If traditional temporary prostheses are used, then the procedure is simple, but the price is close to the price of the permanent implant, constituting a financial burden
Solution Approach 1:
The patent applies this principle by using polyethylene material for the temporary spacer implant, which is less expensive than metal or ceramic materials used for permanent implants. The spacer serves its temporary function and is then removed, avoiding the need for expensive long-term materials while still providing adequate mechanical support during the healing period.
Solution Approach 2:
The patent employs segmentation by separating the treatment into distinct phases: a temporary spacer phase using cost-effective polyethylene material, followed by permanent implantation. This segmentation allows the use of different materials optimized for different functional requirements, reducing overall treatment cost by not using expensive materials for the temporary phase.
4Adaptability or versatility
If a permanent prosthesis is implanted in children during their developmental stages, then the bone growth is disrupted, but without a prosthesis the patient cannot perform daily activities
Solution Approach 1:
The patent applies this principle by using a temporary polyethylene spacer implant that provides immediate mechanical support and allows children to perform daily activities after surgery. The spacer is designed to be short-lived, typically remaining in place for 6-12 weeks before being replaced by a permanent prosthesis once the child's growth is better controlled or accommodated through growth-friendly surgical techniques.
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 mega spacer provides a customized, long-lasting solution for bone reconstruction, allowing patients to perform daily activities and facilitating antibiotic delivery, reducing the need for prolonged bed rest and costly surgeries.
Implementation Method 1
manufactured by 3D printing and made from medical-grade material, which is selected from the Polyamide family. The manufacturing material is Nylon PA2200
Data Source
AI summary
A patient specific mega spacer (1, 2) for the patients having severe bone loss resulted from both of malignant and benign tumours, infection of the primary implant, or factures and severe bone loss due to trauma. The spacer was designed to fit the bone shape and anatomy based on the images captured from the CT-scan, x-ray MRI and/or ultrasound. The spacer designed with specific shape to maintain the gap and treat the infection by using a mix of antibiotics stored in reservoir (12) inside the spacer body and released with certain rate based on the medical needs. The assembly and the mechanism of the space will fit the original range of motion and recover the bone loss. The spacer manufactured by 3D printing with accredited biomaterials Nylon PA2200 to be implanted into the patient body.