In-Patient Stent Trimming for Accurate Ureteral Length Adjustment
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Solution Overview
Problem
Current medical stents, particularly ureteral stents, often require estimation of length before implantation, leading to potential discomfort and complications due to incorrect sizing, and existing trimming methods outside the body can result in excess material causing irritation and require additional procedures.
Innovation Solution
A device comprising an outer and inner tube with a distal end effector configured to trim the stent within the patient, allowing for precise adjustment of stent length during implantation, utilizing various mechanisms such as sharpened edges, blades, and rotatable components to securely engage and trim the stent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If stent length is estimated before implantation, then procedure simplicity is maintained, but stent sizing accuracy deteriorates leading to patient discomfort and potential complications
Solution Approach 1:
The stent is pre-loaded onto the delivery catheter at the estimated correct length before implantation. This preliminary positioning allows the stent to be accurately placed initially, and then trimmed if needed, combining the benefits of pre-planning with post-adjustment capability.
Solution Approach 2:
The trimming device integrates cutting functionality directly into the delivery system, allowing the stent to be trimmed in situ within the patient's body. This self-contained approach eliminates the need for separate trimming procedures and enables precise length adjustment based on actual anatomical conditions.
2Manufacturing precision
If stent is trimmed outside the body before implantation, then manufacturing precision is improved, but device complexity increases due to additional procedures and excess material removal
Solution Approach 1:
The trimming function is merged with the stent delivery system. The cutting device is integrated into the delivery catheter, combining two separate operations (delivery and trimming) into a single unified procedure performed in situ, thereby reducing overall procedural complexity despite achieving precise trimming.
Solution Approach 2:
A delivery catheter serves as an intermediary tool that both delivers the stent and houses the trimming mechanism. This intermediary device enables precise in situ trimming without requiring separate external trimming procedures, simplifying the overall process while maintaining manufacturing precision.
3Adaptability or versatility
If excess stent material is left in the bladder, then adaptability to anatomical variations is improved, but object-generated harmful factors increase due to tissue irritation and discomfort
Solution Approach 1:
The stent length is made dynamically adjustable through in situ trimming. Rather than relying on fixed pre-manufactured lengths, the stent can be precisely trimmed to the optimal length for each patient's anatomy, eliminating excess material that would cause irritation while maintaining necessary adaptability.
Solution Approach 2:
The trimming mechanism uses a sharp cutting edge that mechanically severs excess stent material. This simple mechanical cutting action efficiently removes unwanted portions of the stent, eliminating harmful excess material while preserving the adaptability of the remaining stent length to match individual anatomical requirements.
Data Source
AI summary
Devices and methods for trimming a stent to a desired length with an outer tube and an inner tube having a distal end and a diameter configured to receive a portion of the stent in excess of the desired length. The inner tube may move within the outer tube and the distal end may include an end effector configured to trim the portion from the stent while the device and stent are within a patient.