Expandable Percutaneous Sheath for Minimally Invasive Access
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Solution Overview
Problem
Current percutaneous nephrostomy systems face challenges in creating a small diameter tissue tract for large diameter instrument introduction, requiring multiple steps and angular shearing forces that can be traumatic and inefficient.
Innovation Solution
A percutaneous access sheath with a variable diameter distal section restrained by a perforated or scored film jacket, which expands upon balloon inflation to increase diameter, allowing for smaller cross-sectional insertion and larger profile accommodation for instrument access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a small diameter puncture is created to minimize tissue trauma, then tissue trauma is reduced, but the available space for diagnostic or therapeutic instruments is limited
Solution Approach 1:
The sheath incorporates a collapsible distal section that can dynamically change diameter - collapsed during insertion to minimize tissue trauma, then expanded within the tract to provide large working lumen for instruments. This dynamic transformation resolves the contradiction between small access size and large instrument space.
Solution Approach 2:
The sheath design allows the distal section to be nested within itself in a collapsed state during insertion, then unfold to provide expanded working space. This nesting principle enables the same structure to occupy minimal space during insertion while providing maximal space during use.
2Reliability
If multiple sequential sheaths are advanced to create the tract, then tract formation is achieved, but the number of procedural steps increases
Solution Approach 1:
The invention combines tract formation and sheath deployment into a single integrated device. The expandable sheath creates the tract and establishes the working lumen simultaneously in one placement action, eliminating the need for multiple sequential sheath advancements while maintaining reliable tract formation.
Solution Approach 2:
The single sheath device performs multiple functions: it creates the tract through tissue, establishes the working lumen, and provides the access pathway for instruments. This multi-functionality reduces the number of procedural steps while ensuring reliable tract formation.
3Ease of operation
If axial pressure is applied to advance the sheath, then sheath placement is achieved, but kinking of the tapered catheter or perforation of the renal pelvis may occur
Solution Approach 1:
The sheath transitions from a flexible collapsed state during low-force insertion to a rigid expanded state after placement. This dynamic rigidity change allows easy insertion without excessive axial pressure while preventing kinking and perforation once deployed.
Solution Approach 2:
The sheath utilizes a flexible membrane structure that can be collapsed to a small profile for safe insertion through minimal axial pressure, then expanded to provide structural support and prevent kinking or perforation during instrument passage.
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
Facilitates minimally invasive procedures by enabling the passage of large instruments through a small tissue tract with reduced trauma and fewer steps, improving access and procedural efficiency.
Implementation Method 1
the distal section of the percutaneous access sheath expands upon balloon inflation to increase diameter
Data Source
AI summary
Disclosed is an expandable percutaneous sheath, for introduction into the body while in a first, low cross-sectional area configuration, and subsequent expansion to a second, enlarged cross-sectional configuration. The sheath is maintained in the first, low cross-sectional configuration by a tubular restraint. In one application, the sheath is utilized to provide access for a diagnostic or therapeutic procedure such as percutaneous nephrostomy or urinary bladder access.