Multi-shield spinal access system for nerve protection
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Solution Overview
Problem
Current microsurgical spinal bone resections and spinal decompressions face challenges in accessing the intervertebral disc due to the limited dimensions of the anatomic window of Kambin's triangle, requiring longer working shields that can safely introduce implants into the disc space.
Innovation Solution
The introduction of a second, inner shield through a first, outer shield, where the inner shield extends past the outer shield to protect nervous tissue, allowing for safe placement and protection of nerves during disc space access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single long working shield is used to access the intervertebral disc through Kambin's triangle, then the disc space can be reached, but the risk of damaging nervous tissue increases
Solution Approach 1:
The single long shield is divided into two separate shields: an outer shield that stops at the facet joint line and an inner shield that extends to the disc level. This segmentation allows each shield to have a optimized length, eliminating the need for a excessively long single shield while maintaining access to the disc space.
Solution Approach 2:
The outer shield serves as an intermediary structure that provides visual control and protection during the placement of the inner shield. It acts as a guide and protective barrier, allowing the inner shield to be positioned accurately while preventing direct contact between instruments and nervous tissue.
2Reliability
If a longer working shield is used to reach the disc space safely, then nerve protection improves, but tissue trauma and insertion difficulty increase
Solution Approach 1:
By dividing the protective function into two shields of appropriate lengths, each shield can be inserted separately with minimal trauma. The outer shield is inserted first to establish the access path, followed by the inner shield that provides the actual nerve protection at the disc level.
Solution Approach 2:
The outer shield is inserted and positioned first to create a protected access channel and provide visual control. This preliminary action establishes a safe pathway that minimizes tissue disruption before the inner shield is introduced.
3Manufacturing precision
If direct visual control is maintained during disc access, then surgical precision improves, but the complexity of the access system increases
Solution Approach 1:
The visual control function is assigned to the outer shield, which has a larger diameter suitable for accommodating visualization instruments. This allows direct visual control to be maintained during the placement of the inner shield and subsequent disc access procedures.
Solution Approach 2:
The outer shield serves multiple functions: it provides structural support for visualization, guides the placement of the inner shield, and acts as a protective barrier. This multi-functionality reduces the need for additional separate devices.
Data Source
AI summary
An access device for accessing an intervertebral disc having an outer shield comprising an access shield with a larger diameter (˜16-30 mm) that reaches from the skin down to the facet line, with an inner shield having a second smaller diameter (˜5-12 mm) extending past the access shield and reaches down to the disc level. This combines the benefits of the direct visual microsurgical/mini open approaches and the percutaneous, “ultra-MIS” techniques.