Helical Tendon Cutting Apparatus for Lengthening Without Transection
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Solution Overview
Problem
Current methods for tendon lengthening, such as z-plasty, require complete transection of the tendon, leading to discontinuity and complications in surgical reattachment and lengthening of contracted tendons.
Innovation Solution
A helical or spiral cutting apparatus and method using a cutting blade guided by a shaft with a helical engagement mechanism, allowing for lengthening of tendons without continuous transection by making a helical cut along the tendon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a tendon is completely transected to achieve lengthening, then additional tendon length is obtained, but the tendon loses continuity and requires complex surgical reattachment
Solution Approach 1:
The tendon is divided into multiple discrete cuts rather than a single complete transection. The helical blade creates several partial cuts through the tendon substance, segmenting the cutting action while maintaining the tendon's external continuity and blood supply.
Solution Approach 2:
The cutting action is moved from a transverse plane to a helical path through the tendon. By rotating the blade along the tendon's longitudinal axis while cutting, the incision follows a spiral trajectory, creating lengthening without complete separation of tendon ends.
2Length of moving object
If a tendon is completely transected for lengthening, then the desired length is achieved, but surgical complexity increases due to reattachment requirements
Solution Approach 1:
The helical cutting pattern is pre-determined by the blade's orientation and rotation path. The surgeon positions the blade at a specific angle and rotates it through a controlled number of turns, automatically creating the desired helical cuts without requiring complex manual maneuvering or multiple surgical steps.
Solution Approach 2:
The cutting geometry is controlled by adjusting parameters such as the blade's initial angle relative to the tendon axis, the number of rotations, and the rotation speed. By changing these parameters, different cutting patterns and lengthening amounts are achieved with a single standardized device and motion.
3Stability of the object's composition
If a helical cutting path is used to maintain tendon continuity, then surgical complexity is reduced, but precise control of the cutting path is required
Solution Approach 1:
The blade follows a curved helical path rather than a straight line, naturally guiding the cut through the tendon substance. The rotational motion combined with axial advancement creates a spiral trajectory that is easier to control and more forgiving of minor positioning errors compared to attempting precise straight-line cuts.
Solution Approach 2:
The helical cutting motion self-regulates the depth and distribution of cuts. As the blade rotates and advances, each rotation automatically creates a cut at a consistent depth and angle, with the tendon's own structure guiding the blade's path and limiting excessive penetration.
Data Source
AI summary
An apparatus and method for elongating a tendon including a cutting blade and a cutting guide supporting the cutting blade in such a way that the cutting blade is movable through at least a portion of a tendon in a helical path so as to make a helical cut in the tendon which allows elongation of the tendon.