Nested Cannula Site Marker Delivery System
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Solution Overview
Problem
Existing methods for marking biopsy sites are often invasive, inaccurate, or difficult to detect, particularly in breast cancer procedures, as they require additional surgical procedures or temporary markers that are hard to localize.
Innovation Solution
A site marker delivery system comprising an outer cannula with an inner lumen and a trigger mechanism for precise placement of a marker at a biopsy site, which can be used with stereotactic biopsy systems or as a handheld device, featuring a collapsible sheath for protection and adjustable grommet for accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a location wire guide with helical coil is used to mark the biopsy site, then the marker can be locked in position about the lesion, but the procedure requires additional invasive surgical techniques and the marker is temporary requiring removal after surgery
Solution Approach 1:
The marker is nested within the inner cannula, which is itself nested within the outer cannula. This allows the marker to be delivered through the biopsy tract without requiring separate invasive surgical procedures for implantation. The nested structure enables sequential deployment where the inner cannula with marker is advanced through the outer cannula to the target site.
Solution Approach 2:
The marker is pre-loaded into the inner cannula before the biopsy procedure. This preliminary preparation allows the marker to be deployed immediately after tissue sampling without requiring a second surgical intervention. The trigger mechanism is also pre-configured to enable simple actuation at the target site.
2Object-affected harmful factors
If biocompatible dyes or stains are used to mark breast lesions, then the marking procedure is less invasive, but the stains are difficult to detect fluoroscopically and may not be permanent
Solution Approach 1:
The marker combines multiple materials with complementary properties: a biocompatible outer shell for tissue compatibility, and an inner core material that is fluoroscopically visible. This composite structure allows the marker to be both less invasive than wire guides and detectable via fluoroscopy, overcoming the limitations of dye-only approaches.
Solution Approach 2:
Different portions of the marker have different properties: the outer surface is biocompatible for tissue interaction, while the inner core provides fluoroscopic visibility. This local differentiation of material properties allows the marker to simultaneously achieve biocompatibility and detectability without requiring invasive surgical implantation.
3Reliability
If markers are implanted directly into the patient's body using invasive surgical technique, then the marker placement is permanent and easily detectable, but the procedure requires additional surgical intervention
Solution Approach 1:
The biopsy procedure and marker implantation are merged into a single integrated process. The same biopsy needle tract is used to deliver the marker, eliminating the need for separate surgical interventions. The trigger mechanism allows the marker to be deployed immediately after tissue sampling by simply advancing the inner cannula, combining two procedures into one efficient operation.
4Manufacturing precision
If a trigger mechanism connected to the inner cannula is used for marker delivery, then the marker can be precisely placed at the biopsy site, but the device structure becomes more complex
Solution Approach 1:
The delivery system is segmented into distinct functional components: the outer cannula for access, the inner cannula for marker delivery, and the trigger mechanism for controlled deployment. This segmentation allows each component to be optimized for its specific function while maintaining overall system simplicity. The trigger mechanism is designed as a separate operable element that controls the relative movement between the segmented cannulas.
Data Source
AI summary
A site marker delivery system is provided. The site mark delivery system includes an outer cannula having an open distal end. The outer cannula defines an inner lumen in which an inner cannula may be received. A marker is also positioned within the inner lumen of the outer cannula. The inner cannula further includes a trigger mechanism that when actuated injects the marker through the open distal end of the outer cannula into a biopsy site.