Retractable Sheath Surgical Instrument for Safe ICG Injection
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Solution Overview
Problem
Current surgical injection needles pose safety risks due to their protruding nature, lead to tissue sticks, and complicate passage through laparoscopic ports, especially when using indocyanine green (ICG) for near-infrared imaging, as leaked ICG reduces marking or mapping effectiveness and precise injection is challenging.
Innovation Solution
A surgical instrument featuring a retractable sheath for the injection needle, allowing controlled exposure and retraction, combined with a robotic catheter unit that includes a syringe carriage, movable handle, and kick-back assembly for precise fluid delivery and drip prevention, ensuring a fluid-tight seal and automatic needle covering to prevent fluid loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a long needle catheter is used for injection in robotic procedures, then injection capability is provided, but safety risks increase and tissue sticks occur
Solution Approach 1:
The needle is nested within a protective sheath that can be extended or retracted. The sheath surrounds the needle during safe passage through tissue, then can be retracted to allow needle exposure for injection, and re-extended to cover the needle after injection. This nesting mechanism allows the needle to be both protected when not in use and accessible when needed.
Solution Approach 2:
The protective sheath is designed to be dynamically adjustable between extended and retracted states. This dynamic configuration allows the system to adapt between two functional modes: safety mode (sheath extended, needle covered) and injection mode (sheath retracted, needle exposed), resolving the contradiction between safety and functionality.
2Ease of operation
If a protruding catheter needle is used, then injection access is provided, but safety risks to users and inadvertent tissue sticks increase
Solution Approach 1:
The needle is nested within a protective sheath that extends beyond the needle tip during safe passage and retraction phases, then can be retracted to allow needle exposure for injection. This nesting provides automatic protection during handling and transport while maintaining injection capability when needed.
Solution Approach 2:
The protective sheath acts as an intermediary element between the hazardous needle and the external environment. It provides a safety buffer during handling, storage, and passage through tissue, while allowing controlled interaction with the needle only when injection is required and properly positioned.
3Ease of operation
If the catheter needle is passed through a laparoscopic port with pressure seals, then access to the surgical site is achieved, but the protruding needle complicates passage
Solution Approach 1:
The needle is nested within an outer protective sheath that provides a smooth, continuous surface for passage through the laparoscopic port and pressure seals. This outer sheath protects the needle from damaging the port seals and provides a more compliant profile for navigation through tight spaces, while the needle remains protected and inaccessible during this phase.
4Adaptability or versatility
If ICG is injected using a simple catheter, then injection is provided, but leaked ICG reduces marking or mapping effectiveness
Solution Approach 1:
The protective sheath provides dynamic control over needle exposure, allowing precise timing of injection. The sheath can be retracted to expose the needle only when the tip is precisely positioned in the target tissue, and re-extended to cover the needle immediately after injection. This dynamic control prevents leakage and ensures precise delivery of ICG to the intended location.
Solution Approach 2:
The protective sheath allows preliminary positioning and verification of needle placement before injection begins. The needle can be advanced to the target site while covered by the sheath, positioned precisely under imaging guidance, and only then is the sheath retracted to allow injection. This preliminary positioning action ensures accurate delivery and prevents misplaced injection.
5Reliability
If a retractable sheath is added to cover the needle, then safety risks are reduced and fluid loss is minimized, but device complexity increases
Solution Approach 1:
The protective sheath is designed as a simple tubular structure that nests over the needle, providing safety and fluid containment functions. The nesting configuration allows the sheath to be a separate, simple component that adds minimal complexity while providing multiple safety functions: physical protection, fluid containment, and controlled access.
Solution Approach 2:
The protective sheath serves multiple functions simultaneously: it protects the needle from damage and exposure, contains leaked fluid, provides a smooth profile for passage through ports, and enables controlled timing of needle exposure. This multi-functionality justifies the added component by providing several benefits from a single structural addition.
Data Source
AI summary
A surgical instrument includes a housing (20), a syringe carriage (40), a movable handle (25), a shaft (30), a needle sheath (50), and a needle (60). The syringe carriage is operably coupled to the housing and configured to couple to a syringe. The movable handle is movable relative to the housing and operably coupled to the syringe carriage to distally advance the syringe carriage. The shaft extends distally from the housing and defines a lumen. The needle sheath extends through the lumen of the shaft, defines a lumen, and is movable relative to the shaft between an extended condition and a retracted condition. The needle extends through the lumen of the needle sheath and is configured to operably couple to a syringe coupled to the syringe carriage.