Cam-Driven Percussion Cutter for Vertebral Endplate Preparation
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Solution Overview
Problem
Current surgical tools for vertebral endplate preparation in spinal surgery lack efficiency and control during disc space cleaning and endplate preparation, necessitating safer and more controlled methods for receiving inter-body implant materials.
Innovation Solution
Power-operated, hand-held instruments that convert rotary input power to reciprocating motion with percussion action in either forward or reverse direction, accommodating different tissue treatment tools and maintaining distracted disc space height using a distractor and keeper arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional surgical tools are used for vertebral endplate preparation, then the surgical procedure can be performed, but the efficiency and control during disc space cleaning and endplate preparation are insufficient
Solution Approach 1:
The patent replaces conventional manual mechanical surgical tools with a power-operated system that converts rotary motion to reciprocating motion. The powered instrument includes a rotary power source coupled to a cam mechanism that transforms continuous rotation into reciprocating linear motion of the treatment tool, thereby improving both efficiency through automated power delivery and control through regulated mechanical motion patterns.
Solution Approach 2:
The invention introduces dynamic motion characteristics by converting steady rotary motion into reciprocating motion with variable velocity profiles. The cam mechanism creates accelerated cutting strokes in the forward direction and controlled return strokes, providing dynamic control that adapts to the varying requirements of disc space cleaning and endplate preparation tasks.
2Productivity
If tissue treatment tools are used with preferred performance directions, then cutting effectiveness is improved, but the instrument must accommodate directional preferences which increases complexity
Solution Approach 1:
The cam mechanism is designed to provide differentiated motion characteristics for forward and reverse strokes, enabling the instrument to accommodate tissue treatment tools with preferred performance directions. The cam profile creates accelerated cutting motion in the preferred direction while providing controlled deceleration and return motion, thereby optimizing cutting effectiveness without requiring separate instruments for different directional preferences.
3Reliability
If distractor and keeper arrangement is used to maintain distracted disc space height, then implant reception is improved, but the device complexity increases
Solution Approach 1:
The distractor and keeper functions are merged into a single integrated arrangement that works in conjunction with the powered instrument. The keeper component is shaped to cooperate with the powered instrument's structure, combining disc space distraction maintenance with the cutting function in a unified system rather than requiring separate independent devices.
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
Enhances the effectiveness of tissue treatment tools by providing controlled and efficient cutting actions, improving the safety and efficiency of endplate preparation during spinal surgery.
Implementation Method 1
a cam mechanism for converting the rotary motion of a power source to reciprocating motion of the cutter shaft
Implementation Method 2
a spring for cushioning the cutter shaft
Data Source
AI summary
A hand-held instrument, with a rotary power input to a camshaft, has cam and follower arrangement to provide a reciprocating shaft output. A cutter is provided on the output shaft. In one example, rotating cam percussion is transmitted to the cutter by engaging the cutter with the tissue to be cut, and pushing the instrument forward toward the cutter. In another example, rotating cam percussion is transmitted to the cutter by engaging the cutter with the tissue to be cut, and pulling the instrument back toward the user while maintaining engagement of the cutter with the tissue. In both examples, the cutter remains in idle condition until an axially directed load, forward in the one example, or backward on the other example, is placed on the cutter by moving the instrument forward or backward, respectively, while the camshaft is rotating. A distractor with frame is used to spread and maintain space between vertebral bodies, enabling entrance of the cutter.