Pivoting Disc Implant Insertion Through Oblique L5-S1 Access
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Solution Overview
Problem
Existing minimally invasive spinal surgery techniques for accessing the L5-S1 intervertebral space are limited by the need for large incisions and cause significant damage to blood vessels and nerves, and require unstable placement of prosthetic disc implants due to limitations in inserting implants into the front, posterior, or side of the disc space.
Innovation Solution
A method and system that allow for a minimally invasive procedure to access the intervertebral space along an oblique pathway, enabling the insertion of a disc implant diagonally and pivoting it within the disc space to achieve stable, midline symmetric distribution, using a retractor instrument with ipsilateral and contralateral blades to retract iliac vessels and an introducer instrument to pivot the implant into position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a direct anterior approach is used to access the intervertebral space, then precise midline placement of the prosthetic disc is achieved, but significant surgical disruption of the anterior annular element and mobilization of major vascular structures is required
Solution Approach 1:
The approach is segmented into two independent pathways: one for accessing the disc space (through the annular element) and another for accessing the anterior longitudinal ligament. This allows the implant to be inserted laterally while the allograft is delivered anteriorly, avoiding the need for a single large anterior exposure that would disrupt both structures simultaneously.
Solution Approach 2:
The implant insertion pathway is moved from the traditional anterior midline approach to a lateral approach through the annular element. This dimensional change allows simultaneous access to the disc space without requiring mobilization of the major anterior vascular structures, as the vessels remain protected in their anterior position.
2Strength
If an anterolateral transpsoatic approach is used to access the intervertebral space, then the anterior longitudinal ligament remains intact, but the iliac vessels must be mobilized and injury to the left iliac vessel is a complication
Solution Approach 1:
The implant insertion pathway is extracted from the anterior transpsoatic route and moved to a lateral approach through the annular element. This separates the implant delivery path from the vascular structures, eliminating the need to mobilize the iliac vessels while maintaining access to the disc space.
Solution Approach 2:
The annular element serves as an intermediary structure that provides access to the disc space without requiring direct exposure of the anterior longitudinal ligament or mobilization of the iliac vessels. The lateral approach uses the annular element as a natural pathway, avoiding harmful interaction with the vascular structures.
3Ease of manufacture
If prosthetic disc implants are inserted into the front, posterior, or side of the disc space using existing techniques, then the implant can be placed, but stable midline symmetric distribution is not achieved
Solution Approach 1:
A guide instrument is inserted first to establish the precise midline position and orientation within the disc space. The prosthetic implant is then attached to this guide instrument, ensuring that the implant is delivered exactly to the predetermined midline position with correct orientation, achieving stable symmetric distribution from the beginning.
Solution Approach 2:
Fluoroscopic imaging provides real-time feedback during the insertion procedure to verify the position and orientation of both the guide instrument and the prosthetic implant. This allows the surgeon to make adjustments to ensure precise midline placement and symmetric distribution before final implantation.
Data Source
AI summary
Disclosed methods, devices and systems are suitable for performing a minimally-invasive procedure for accessing the intervertebral space along an oblique pathway with an insertion instrument that holds a disc implant, and reorienting the angular relationship between instrument and implant while the implant is inside the body (for example at or within the disc space).