Frustoconical Screw Extractor Tip for Damaged Orthopedic Screws
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Solution Overview
Problem
Conventional orthopedic screw extractors fail to effectively attach to and remove damaged or stripped screws, leading to difficulties in extraction and excessive bone loss during surgical procedures.
Innovation Solution
An orthopedic screw extractor with a frustoconical screw extracting tip featuring multiple threads and flutes, designed to securely engage and remove damaged screws, utilizing a handle for rotational torque and a cannulation for precise positioning, with a titanium nitride coating for enhanced grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional orthopedic screw extractors are used, then the extraction procedure can be performed, but they fail to provide sufficient bite to lock onto damaged screws, resulting in excessive bone loss
Solution Approach 1:
The patent applies parameter changes by modifying the thread geometry parameters (thread angle, pitch, depth) and the frustoconical shape parameters (angle relative to longitudinal axis) of the extracting tip to optimize the bite and locking mechanism on damaged screws, thereby improving attachment reliability while minimizing bone loss
Solution Approach 2:
The patent employs a frustoconical shape for the extracting tip, utilizing curved surfaces to conform to the damaged screw geometry and improve engagement. The conical curvature allows progressive engagement and secure locking onto the damaged screw surface
2Ease of operation
If conventional screw extractors are used on stripped screws, then extraction can be attempted, but insufficient grip is achieved making extraction difficult and time-consuming
Solution Approach 1:
The patent optimizes thread parameters including thread angle (20-45 degrees), pitch (0.02-0.04 inches), and depth (0.01-0.02 inches) to maximize engagement with damaged screw surfaces, enabling easier extraction and reducing procedural time
Solution Approach 2:
The frustoconical shape with specific angle provides preliminary engagement and self-centering action when the extractor is inserted, preparing the damaged screw for effective thread engagement and subsequent easy extraction
Data Source
AI summary
An orthopedic screw extractor device including a shaft, an end portion about a first end of the shaft for securing to a handle, and a screw extracting tip about a second end of the shaft opposite the first end. The screw extracting tip further includes a generally frustoconical shape having a side at an angle of about 5 to 15 degrees relative to a longitudinal axis of the screw extracting tip. The screw extracting tip further includes first, second and third screw threads and first, second and third flutes circumferentially spaced about the screw extracting tip and extending across an entire length of the screw extracting tip. Each of the screw threads has a lead of about 0.07 to 0.12 inches, a pitch of about 0.02 to 0.04 inches, a thread angle of about 40 to 50 degrees, and a depth of about 0.01 to 0.02 inches.