Patient-Specific Surgical Blocks for Accurate Bone Resection
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Solution Overview
Problem
Current orthopaedic surgical instruments are generic and require guesswork for placement during joint arthroplasty procedures, leading to potential inaccuracies in bone resection and prosthetic implantation.
Innovation Solution
A customized patient-specific orthopaedic surgical system featuring surgical blocks with negative contours matching patient bone contours, coupled with a computer-controlled milling machine, allows for precise bone resection according to a predefined surgical plan generated from medical images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If generic orthopaedic surgical instruments are used, then the same instrument can be used on multiple patients (versatility), but placement requires guesswork and intra-operative decision-making (precision)
Solution Approach 1:
Patient-specific instruments are fabricated before surgery based on pre-operative imaging data (CT or MRI scans). The instruments incorporate patient-specific bone surface contours and anatomical landmarks, allowing precise placement without intra-operative guesswork. This preliminary customization resolves the contradiction by preparing patient-specific tools in advance that maintain versatility across different patients while ensuring high placement precision.
Solution Approach 2:
The patient-specific instruments include bone-contacting surfaces that are negative impressions or copies of the patient's actual bone surface geometry. These copied contours enable the instruments to match and conform precisely to the individual patient's anatomy, achieving accurate placement while the instruments remain reusable for that specific patient's procedure.
2Manufacturing precision
If customized patient-specific instruments are fabricated, then placement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The customization is applied locally to specific critical surfaces of the instruments (bone-contacting surfaces and mounting interfaces) rather than the entire instrument. The bone-contacting surfaces incorporate patient-specific contour data, while other portions of the instrument can use standardized components. This localized customization achieves high placement precision without proportionally increasing overall device complexity.
Solution Approach 2:
All customization and complexity is resolved during the pre-operative planning phase where patient-specific instruments are fabricated based on imaging data. Once manufactured, the instruments are ready for use without requiring complex intra-operative adjustments or decision-making, thereby managing complexity through advance preparation.
3Device complexity
If generic instruments requiring guesswork are used, then device simplicity is maintained, but surgical time increases due to intra-operative decision-making
Solution Approach 1:
Patient-specific instruments are fabricated before surgery with all placement parameters predetermined based on pre-operative imaging and surgical planning. This eliminates intra-operative decision-making and guesswork, allowing the surgeon to simply attach and use the instruments according to the pre-planned surgical protocol, thereby improving surgical efficiency without requiring complex intra-operative adjustments.
Solution Approach 2:
The patient-specific instruments are designed to self-align and self-position on the patient's bone through their customized bone-contacting surfaces that match the patient's unique anatomy. This self-aligning capability eliminates the need for surgeon guesswork and intra-operative decision-making about instrument placement, improving surgical efficiency while maintaining relatively simple attachment procedures.
Data Source
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AI summary
A customized patient-specific orthopaedic surgical system includes a first surgical block, a second surgical block, and a computer-controlled milling machine. The first surgical block includes a first bone-facing surface having a first customized patient-specific negative contour to receive a first corresponding contour of a bone of a patient and a first mounting surface. The second surgical block includes a second bone-facing surface having a second customized patient-specific negative contour to receive a second corresponding contour of the bone of the patient and a second mounting surface to be separately mated with the first mounting surface. The computer-controlled milling machine includes a third mounting surface to be separately mated with the first mounting surface of the first surgical block.