Balloon-Expanded Access Sheath for Low-Trauma Kidney Access
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Solution Overview
Problem
Conventional percutaneous nephrolithotomy procedures for accessing the kidney's collecting system are cumbersome, causing unnecessary tissue trauma and requiring multiple steps, dilators, and an access sheath that cannot be adjusted in situ.
Innovation Solution
An access assembly comprising an inflatable balloon, a dilation tip, and an expandable access sheath that surrounds the balloon, allowing for controlled expansion and adjustment of the access sheath to form a working channel of predetermined size without the need for multiple dilators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple rigid dilators are used to dilate the passage, then the passage can be expanded to accommodate the access sheath, but unnecessary tissue trauma and damage occur
Solution Approach 1:
The patent employs an inflatable dilator that uses fluid pressure to expand the passage. The dilator is inserted in a collapsed state and then inflated with fluid to dilate the tissue, avoiding the need to pass multiple rigid dilators through the soft tissues. This pneumatic/hydraulic approach reduces mechanical trauma while achieving the same dilation effect.
Solution Approach 2:
The dilator transitions from a static, rigid structure to a dynamic, inflatable structure. The dilator can change its diameter by inflating or deflating, allowing it to be inserted in a small profile and then expanded to the required size. This dynamic capability eliminates the need for sequential rigid dilators of increasing size.
2Ease of operation
If multiple dilators including rigid and inflatable dilators are used, then the passage can be adequately dilated, but the number of procedure steps increases greatly
Solution Approach 1:
The patent combines the functions of multiple dilators into a single inflatable dilator device. The device integrates the dilation function that previously required multiple rigid dilators of different sizes into one instrument that can be inflated to the required diameter, thereby reducing the number of steps from passing multiple dilators to passing and inflating a single dilator.
Solution Approach 2:
The inflatable dilator serves multiple functions: it acts as both the dilation instrument and the access sheath. The device can be inflated to different diameters to accommodate different sized access sheaths, providing universal applicability that replaces the need for multiple specialized dilators.
3Ease of operation
If the access sheath is passed between soft tissues and the inflatable dilator, then the access sheath can be positioned, but further tissue damage occurs
Solution Approach 1:
The access sheath and dilator are merged into a single integrated device. The sheath is passed over the dilator in a coordinated manner, and the dilator is inflated to expand the sheath simultaneously, eliminating the need to force the sheath between the dilator and tissue. This integration reduces friction and mechanical trauma during positioning.
4Ease of manufacture
If the access sheath size is selected before the procedure, then the sheath can be prepared in advance, but the sheath cannot be expanded or adjusted after being in place
Solution Approach 1:
The access sheath is designed with dynamic expansion capability through integration with the inflatable dilator. After the sheath is positioned, the dilator can be inflated to expand the sheath to different diameters, allowing size adjustment in situ. This dynamic feature enables the surgeon to adapt the sheath size during the procedure based on actual needs, rather than being locked into a pre-selected size.
Solution Approach 2:
The sheath diameter parameter can be changed after insertion by controlling the inflation pressure of the integrated dilator. The system allows continuous adjustment of the sheath size by varying the inflation volume, providing parameter flexibility that was not possible with traditional fixed-size sheaths.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces tissue trauma, simplifies the procedure by minimizing steps and dilators, and allows for in situ adjustment of the access sheath size, enhancing procedural efficiency and safety.
Implementation Method 1
an inflatable dilator that has an initial small diameter can be passed over the guidewire and expanded by filling it with a fluid, such as saline
Data Source
AI summary
In one embodiment, an expandable access sheath including a planar sheet of material that is configured to be rolled up around an inflatable balloon, the sheet comprising an inner surface, an outer surface, a leading edge, a trailing edge, a proximal edge, and a distal edge, the sheet further including at least one locking tab that extends from either the inner surface or the outer surface of the sheet, wherein the leading edge of the sheet is configured to interface with the locking tab to lock the access sheath in a predetermined configuration in which the access sheath forms an inner working channel having a predetermined cross-sectional dimension after the access sheath has been expanded by the inflatable balloon.