Spinal Retractor Pin Channel Layout to Prevent Blade Withdrawal
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Solution Overview
Problem
Existing spinal retractor systems face issues such as accidental blade withdrawal due to tissue pressure, require stiff and bulky materials, and are cumbersome to maintain, especially when retrieving shims for better access.
Innovation Solution
The retractor system features a channel oriented differently from the blade direction, allowing for a pin to be anchored at an angle, reinforcing the blades with a pin and dilator system, and using shims to prevent tissue ingress, all while enabling easier access and reducing the risk of blade removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the channel is oriented parallel to the blade direction, then the structure is simple and easy to manufacture, but the pin cannot effectively prevent accidental blade withdrawal under tissue pressure
Solution Approach 1:
The patent changes the channel orientation from parallel to perpendicular relative to the blade direction, introducing a dimensional change that allows the pin to engage the blade at a right angle. This perpendicular orientation creates a mechanical interlock that effectively prevents accidental blade withdrawal while maintaining structural simplicity
2Strength
If very stiff material is used to expand from the frame structure, then the retractor can maintain position against tissue pressure, but the structure becomes bulky and difficult to manipulate
Solution Approach 1:
The patent employs thin blade structures that can be made of relatively flexible material yet maintain positional stability through the pin-channel mechanical interlock. The perpendicular pin orientation provides retention without requiring bulky stiffening elements, allowing thin-film-like blades to function effectively
Solution Approach 2:
By orienting the pin channel perpendicular to the blade, the patent creates a retention mechanism that operates in a different dimensional plane than the blade's primary function. This allows the blade to remain thin and flexible while the perpendicular pin provides the necessary strength and position maintenance
3Reliability
If shims are fixed to the blade or placed between blade edges, then tissue and instruments are prevented from ingress, but the shims cannot be retrieved separately to allow easier access to the surgical site
Solution Approach 1:
The patent segments the retractor system into distinct components: the blade, the pin, the channel, and the shim. The pin and channel mechanism can be independently manipulated, allowing the shim to be removed or adjusted separately from the blade structure, facilitating easier access to the surgical site when needed
Data Source
AI summary
Retractor system for spine surgery comprising two retractor members (1,2) being each made of a blade (1) and a proximal part forming a frame (2), at least two pins (10) having each a distal end configured to be anchored in a vertebra, and a blocking mechanism (5) for maintaining the retractor members (1,2) at a certain distance from each other; wherein at least one retractor member (1,2) contains a channel (3) that is configured to slidably hold said pin (10); characterized by the fact that the channel (3) is oriented along a direction that differs from the blade (1) direction. The invention also relates to a retractor system that includes at least one shim (12) with guiding grooves (15) ending before the shim distal end.