Shielded Puncture Wire for Fluoroscopy-Free Renal Access
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Solution Overview
Problem
Current nephrostomy tube creation techniques, such as the Lawson and Munch techniques, face challenges including increased radiation exposure, difficulty navigating past large obstructive stones, limited visualization leading to suboptimal calyx selection, and risks associated with wire exposure and handling during nephrostomy procedures.
Innovation Solution
A method and system utilizing a puncture wire shielded in a sheath, advanced through a ureteroscope for direct visualization and secure placement into a selected calyx, with locking mechanisms to secure the wire and sheath, allowing for fluoroscopy-free calyx selection and reduced tissue trauma, and enabling antegrade wire exchange without exposing the wire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluoroscopy is used to guide nephrostomy puncture wire tract location, then the physician can locate the puncture site, but radiation exposure increases
Solution Approach 1:
The patent replaces fluoroscopy (radiation-based imaging) with direct visualization through the ureteroscope (optical imaging). The ureteroscope provides direct visual confirmation of calyx entry and wire placement, eliminating the need for continuous fluoroscopic monitoring and thereby reducing radiation exposure to both patient and physician.
Solution Approach 2:
The ureteroscope acts as an intermediary device that provides direct visual feedback between the physician and the internal anatomy. By inserting the ureteroscope into the urinary tract, the physician can directly visualize the calyx and guide wire placement without relying on indirect fluoroscopic imaging, thus reducing radiation exposure while maintaining precision.
2Ease of operation
If the puncture wire is advanced without a sheath, then the wire can be inserted directly into the calyx, but tissue trauma increases and wire handling becomes difficult
Solution Approach 1:
The sheath is advanced into the calyx before the puncture wire. This preliminary positioning of the sheath creates a protective pathway that guides the wire and prevents direct contact between the wire and surrounding tissues, thereby reducing tissue trauma while facilitating easier wire insertion.
Solution Approach 2:
The sheath serves as a cushioning element that protects tissues from the sharp puncture wire. By having the sheath in place beforehand, the wire is contained within the sheath lumen during advancement, preventing accidental punctures or trauma to adjacent structures and making wire handling safer and easier.
3Ease of operation
If the wire is exposed during handling, then wire manipulation is easier, but the risk of wire damage and tissue injury increases
Solution Approach 1:
The sheath provides localized protection to the wire at critical areas where the wire is most vulnerable. The wire remains exposed only where manipulation is necessary, while being protected within the sheath during advancement and positioning, thus balancing ease of manipulation with wire integrity and tissue safety.
Solution Approach 2:
The sheath acts as an intermediary protective layer between the wire and the external environment. It allows the wire to be manipulated through the sheath lumen while maintaining wire integrity and preventing direct contact with tissues, thereby reducing the risk of wire damage and tissue injury during handling.
4Measurement precision
If direct visualization is used for calyx selection, then calyx selection precision improves, but the procedure complexity increases
Solution Approach 1:
The ureteroscope serves multiple functions: it provides direct visualization for calyx selection, guides wire advancement, and confirms proper wire placement. This multi-functionality eliminates the need for separate imaging devices and complex procedural steps, thereby improving calyx selection accuracy without significantly increasing overall procedure complexity.
Solution Approach 2:
The patent combines the visualization function and wire guidance function into a single integrated procedure using the ureteroscope. By merging these functions, the procedure achieves high calyx selection accuracy while avoiding the added complexity of multiple separate devices and steps that would be required if fluoroscopy and direct visualization were used separately.
Data Source
AI summary
A method for creating a tract in retrograde fashion for nephrostomy tube creation comprising the steps of providing a puncture wire having a tissue penetrating tip shielded in a sheath, inserting the puncture wire and sheath through a channel in an ureteroscope, advancing the puncture wire from the sheath while visualizing under direct vision a position of the puncture wire, advancing the puncture wire through a selected calyx, and inserting antegrade a coaxial catheter over the puncture wire.