Arcuate Cannula Assembly for Spinal Access
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Solution Overview
Problem
Current spinal orthopaedic procedures face challenges in accessing the spine efficiently, particularly due to the need for patient repositioning, high risk of vascular injury, and increased operating time, which complicates procedures like discectomy and interbody fusion.
Innovation Solution
A minimally invasive arcuate cannula assembly is used for a postero-lateral approach, comprising a targeting post, guide arm, and curved penetrating guide member, allowing sequential insertion of graduated cannulas to create an unimpeded access portal to the intervertebral space, reducing muscle retraction, blood loss, and vascular damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lateral interbody fusion approach is used, then access to the intervertebral space is achieved, but the patient must be turned mid-process which increases operating time and complexity
Solution Approach 1:
The arcuate cannula assembly is pre-positioned and secured to the patient's back before the surgical procedure begins. The targeting post is inserted through the skin and subcutaneous tissue to establish the correct trajectory, allowing subsequent cannulas to be advanced along the predetermined arcuate path without requiring patient repositioning. This preliminary setup enables continuous access to the intervertebral space throughout the procedure.
2Ease of operation
If an anterior approach is used to access the spine, then direct access to the spinal column is achieved, but the risk of injury to vascular anatomy increases requiring a vascular surgeon or highly experienced general surgeon
Solution Approach 1:
The arcuate cannula assembly utilizes a postero-lateral approach that accesses the intervertebral space through a specific trajectory avoiding the anterior vascular structures. The curved path of the cannulas is designed to navigate around critical vessels and nerves, allowing the procedure to be performed by orthopaedic surgeons without requiring vascular surgery expertise. This localized approach minimizes exposure to harmful vascular factors while maintaining effective access to the target site.
3Ease of operation
If traditional access methods are used, then the spine can be accessed, but muscle retraction and blood loss increase
Solution Approach 1:
The access procedure is divided into sequential steps using graduated cannulas of increasing size. A small initial incision is made, followed by sequential dilation through progressively larger cannulas (e.g., 12mm, 14mm, 16mm) to reach the final access diameter. This segmented approach minimizes the size of the initial incision and reduces trauma to surrounding muscles and tissues, thereby decreasing blood loss compared to creating a single large opening.
4Stability of the object's composition
If the arcuate cannula assembly is secured to the patient's back, then stable access is achieved, but the setup complexity increases
Solution Approach 1:
The arcuate cannula assembly integrates multiple components into a unified structure: the targeting post, guide arms, and arcuate cannulas are combined in a coordinated system. The guide arms are attached to the targeting post at specific angles, and the arcuate cannulas follow the curvature defined by this assembly. This merging of components creates a stable, self-aligning system where each element supports the others, reducing the need for complex external fixation devices while maintaining positional stability throughout the procedure.
Data Source
AI summary
A system for accessing a spine from a curved postero-lateral approach may include a curved cannula positioned along a curved path from an opening in the skin to a location proximate the spine. A guide member may be first inserted to establish the path between the tissues and fascia, and one or more intermediate cannulas may be temporarily inserted over the guide member to dilate the tissues prior to insertion of the main cannula. An interbody device may be implanted in an intervertebral space through the cannula. The system may include a guide bar removably coupled to a targeting post. The targeting post may be inserted adjacent the spine to provide a target, and the guide bar may be removably attached to the guide member, to guide it along the path to the target location. An external support arm may be secured to any other component of the system.