Controlled Retrieval String for Non-Cystoscopic Urological Removal
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Solution Overview
Problem
Conventional retrieval strings for urological devices cause discomfort, risk of infection, and premature device withdrawal, and are cumbersome for non-cystoscopic removal.
Innovation Solution
The development of urological devices with controlled emergence retrieval strings, including bioerodible components and magnetic buoyant strings, allowing for blind or minimally invasive removal without cystoscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a retrieval string extends through the patient's urethra during the entire deployment period, then the device can be removed without cystoscopy, but the patient experiences discomfort, risk of infection, and potential premature device dislodgement
Solution Approach 1:
The retrieval string is pre-positioned within the device before implantation, but remains concealed within the device structure during the deployment period. The string only emerges when needed for retrieval, allowing the device to be removed without cystoscopy while avoiding patient discomfort and infection risk during normal operation.
Solution Approach 2:
The retrieval string is nested within the device structure during deployment, concealed inside the device body. When retrieval is needed, the string emerges from the device in a controlled manner, allowing removal without exposing the string to the patient's urethra during the treatment period.
2Ease of operation
If a long retrieval string is used to enable patient or physician grasping, then device retrieval is possible, but the string may be accidentally tugged during urination causing pain or premature device dislodgement
Solution Approach 1:
The retrieval string is prepared and positioned within the device before implantation, but its full length is not exposed to the patient's urethra during deployment. The string emerges in a controlled manner only when retrieval is initiated, preventing accidental tugging during normal urination while maintaining retrieval capability.
3Ease of operation
If a retrieval string is provided for device removal, then non-cystoscopic retrieval is enabled, but the string interferes with urine flow direction and increases infection risk by providing a bacterial migration pathway
Solution Approach 1:
The retrieval string is nested within the device structure during deployment, concealed inside the device body. This prevents the string from interfering with urine flow direction and eliminates the bacterial migration pathway that would exist if the string extended through the urethra during the treatment period.
Solution Approach 2:
The retrieval string is extracted from the device structure only at the moment of retrieval, allowing the device to be removed without cystoscopy. During the entire deployment period, the string remains concealed within the device, eliminating infection risk and urine flow interference.
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
Enables safe, comfortable, and efficient removal of urological devices from patients without cystoscopy, reducing infection risk and patient discomfort.
Implementation Method 1
magnetic buoyant strings, allowing for blind or minimally invasive removal without cystoscopy
Data Source
Figure 1~3E
Figure 4~6B
Figure 7~9
AI summary
A urological medical device (54) having a retrieval string (52) is provided. The retrieval string (52) has a proximal end connected the device and an opposed distal end with a cap (56). In a first embodiment, the retrieval string (52) is configured in an initial confined form which, following a period of deployment in a patient's bladder, changes to an unconfined form in which the distal end of the retrieval string (52) is extendible into the urethra (99) to enable extraction of the device from bladder by pulling the retrieval string (52) . The device may include a bioerodible component which permits the retrieval string to take the unconfined form following degradation of the bioerodible component in vivo.