Waterjet Cutting System for Orthopedic Bone Resection
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Solution Overview
Problem
Current cut guides in orthopedic surgery often result in imprecise cuts due to patient movement, lack of experience, or obstructed visual access, and traditional cutting techniques like sawblades can cause inaccuracies or damage to bone or soft tissue, especially when dealing with varying bone densities.
Innovation Solution
A waterjet cutting system utilizing a 3D-printed custom cut guide and a waterjet cutting device with a nozzle that ejects pressurized water or a water-abrasive mixture, guided by a patient-specific cut guide to ensure precise cuts while protecting adjacent tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional sawblade is used for cutting bone, then the cutting device can effectively cut through bone tissue, but the cut precision deteriorates due to skiving caused by varying bone density and hardness
Solution Approach 1:
The patent replaces the traditional mechanical sawblade cutting system with a waterjet cutting system that uses high-pressure fluid dynamics to cut bone. The waterjet nozzle directs a focused stream of pressurized water (optionally with abrasive particles) at the bone, eliminating the mechanical contact that causes skiving. This substitution of mechanical cutting with fluid-based cutting resolves the contradiction by maintaining cutting effectiveness while dramatically improving cut precision regardless of bone density variations.
Solution Approach 2:
The patent employs hydraulic principles by using a waterjet system that delivers high-pressure water (typically 30,000-90,000 psi) through a focused nozzle to cut bone tissue. The hydraulic pressure enables the water stream to erode and cut through bone of varying densities without the mechanical resistance problems that plague sawblades. This hydraulic approach allows precise control of the cutting process while maintaining effectiveness across different bone types.
2Measurement precision
If a cut guide is used to align the cutting device, then the alignment can be improved, but the placement precision deteriorates due to patient movement, lack of experience, or obstructed visual access
Solution Approach 1:
The patent uses patient-specific 3D-printed cut guides that are created as custom copies based on the patient's unique anatomy obtained from pre-operative imaging (CT or MRI scans). These custom guides are manufactured to precisely fit the patient's specific bone geometry and surgical requirements, eliminating the need for manual alignment by the surgeon. The copying approach ensures that each patient receives a guide tailored to their anatomy, thereby improving placement precision regardless of surgeon experience or visual access during surgery.
Solution Approach 2:
The patent implements preliminary action by creating and manufacturing patient-specific cut guides before the surgery, based on pre-operative imaging and planning. All alignment calculations and guide positioning are determined in advance, allowing the guide to be placed quickly and accurately during surgery without requiring complex intraoperative adjustments. This preliminary planning and preparation eliminates the problems of patient movement and surgeon inexperience during the actual cutting procedure.
3Productivity
If a sawblade is used for cutting, then the cutting can be performed, but harmful factors increase due to accidental damage to bone or soft tissue
Solution Approach 1:
The patent replaces the mechanical sawblade system with a waterjet cutting system that uses high-pressure fluid instead of mechanical blades. This substitution eliminates the risk of accidental damage to surrounding soft tissues and bone that can occur with sawblades, particularly when skiving causes unexpected blade movement. The waterjet system provides controlled, precise cutting that stops exactly where directed, without the mechanical forces that can cause unintended tissue damage.
Solution Approach 2:
The patent introduces water (and optionally abrasive particles) as an intermediary medium between the cutting source and the bone tissue. This intermediary allows the cutting energy to be delivered precisely to the target bone while the flexible water stream can be easily controlled and stopped, preventing damage to surrounding tissues. The water acts as a controllable mediator that transfers cutting energy without the rigid, unpredictable mechanical forces of a sawblade.
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 provides more precise cuts, reduces recovery time, minimizes bone damage, and reduces the need for refining cuts by using a personalized approach that adapts to the patient's anatomy, improving surgical efficiency and accuracy.
Implementation Method 1
a waterjet cutting device with a nozzle that ejects pressurized water or a water-abrasive mixture
Implementation Method 2
a waterjet cutting device with a nozzle that ejects pressurized water or a water-abrasive mixture
Data Source
AI summary
Systems (100, 900, 1100), devices, and methods may be used to print or use a patient-specific waterjet cut guide (104, 302, 902, 1102). A method may include receiving, at a processor, image data of a bone (102, 308) of a patient (702), rendering a model of the bone (102, 308) (704) and generating a cut guide model using the model of the bone (102, 308) (706). The method may include printing, using a three-dimensional (3D) printer, a waterjet cut guide (104, 302, 902, 1102) using the cut guide model. A method may include using the patient-specific waterjet cut guide (104, 302, 902, 1102) to perform a resection using a waterjet cutting device, the waterjet cutting device including a nozzle (108, 306, 406, 500A, 500B) insertable into a cut guide slot (106B, 304, 310, 906, 1104) of the patient-specific waterjet cut guide (104, 302, 902, 1102).