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Publication Number
US-11452625-B2
Publication Date
2022-09-27
Expiration Date
Abstract
Provided is a stent which is not easily displaced from a dwell site in a biological lumen and which has an excellent ability to follow a biological lumen. This stent (bile duct stent 100) is to dwell inside a biological lumen (bile duct B) and is provided with a stent main body section (110) having a cylindrical shape. The stent main body section is configured to be capable of expanding and contracting in the radial direction that is approximately orthogonal to an axial direction, has a relatively large expanding force in one portion (center portion) corresponding to the predetermined position at the indwelling site in the biological lumen, and a relatively small expanding force at other portions (both end portions) which have different positions in the axial direction from that of the one portion.
Core Innovation
The invention provides a stent placed in a living body lumen, the stent having a stent main body section with a skeleton portion formed into a cylindrical shape by spirally winding a wire rod. The skeleton portion is formed to be expandable and contractible in a radial direction substantially orthogonal to an axial direction, and the stent main body section includes a portion corresponding to a predetermined position on an indwelling site that exerts a larger expanding force than at least one of two end portions having different axial positions.
The skeleton portion is bent such that crest portions and trough portions are alternately formed in the axial direction, and a downstream skeleton portion is located at the most downstream end of the skeleton portion. The downstream skeleton portion includes two crest portions and other crest portions, where the two crest portions face and separate from each other in a first direction orthogonal to the axial direction, and the other crest portions are disposed between the two crest portions in a circumferential direction.
In the same main body section, a valve section is provided in a downstream end portion located downstream in a flow direction of a fluid flowing in the living body lumen, with a membrane body forming an inlet and an outlet and two support portions supporting the membrane body. The valve section includes a tapered shape in which a width in a second direction orthogonal to the first direction in an axial cross section gradually decreases toward a downstream of the flow direction, and each of the two support portions is formed in a V-shape by the two crest portions and applies force to the outlet to separate the two crest portions from each other along the first direction.
Additional optional structures include a stretch restriction portion arranged to suppress axial stretching, and a removal assistant having an engaging portion that enables recovery of the stent from the living body lumen. Pulling the removal assistant axially causes the skeleton to be bent/deformed and causes a downstream end portion of the stent main body to contract radially while stretching in the axial direction.
Claims Coverage
The provided portion includes one independent claim (clm-00001) and dependent refinements (clm-00002 to clm-00004). Across these claims, the inventive features concentrate on an axially tuned expanding force skeleton, a specific downstream crest geometry that cooperates with a membrane valve section, and optional removal assistance and stretch restriction structures.
Axially distributed radial expanding force in cylindrical spirally wound skeleton
A stent in which the skeleton portion is formed into a cylindrical shape by spirally winding a wire rod and is formed expandably and contractibly in a radial direction substantially orthogonal to an axial direction, the stent main body section having a portion corresponding to a predetermined position on an indwelling site that exerts a larger expanding force than at least one of two end portions that is different in axial position from the portion.
Alternating crest and trough downstream skeleton geometry for valve cooperation
The skeleton portion is bent such that crest portions and trough portions are alternately formed in the axial direction, and includes a downstream skeleton portion located at the most downstream end of the skeleton portion, the downstream skeleton portion having two crest portions and other crest portions where the two crest portions face and separate from each other in a first direction orthogonal to the axial direction, the other crest portions are disposed between the two crest portions in a circumferential direction, and the two crest portions protrude more downstream in the flow direction than the other crest portions.
Membrane valve section with tapered outlet geometry and V-shaped support separation
A valve section provided in a downstream end portion having a membrane body forming an inlet and an outlet through which the fluid flows and two support portions supporting the membrane body, the valve section having a tapered shape in which a width in a second direction orthogonal to the first direction in the axial cross section gradually decreases toward a downstream of the flow direction, and the two support portions each being formed in a V-shape by the two crest portions and applying force to the outlet to separate the two crest portions from each other along the first direction.
Removal assistant for recovery by axial deformation and radial contraction
The stent further includes a removal assistant, where pulling the removal assistant axially causes the skeleton to be bent/deformed and causes a downstream end portion of the stent main body to contract radially while stretching in the axial direction.
Engaging portion in a removal assistant formed from a wire rod
The removal assistant has an engaging portion formed by bending a wire rod to engage a recovery member for recovering the stent from a living body lumen.
Stretch restriction portion that suppresses axial stretching at a defined location
The stent further includes a stretch restriction portion arranged axially to suppress axial stretching, with a downstream end located at an inlet side of at least one of the two support portions.
In clm-00001, the stent combines a cylindrical spirally wound expandable/contractible skeleton with a downstream crest geometry that cooperates with a membrane valve section including tapered outlet geometry and V-shaped support portions that separate crest portions. Dependent claims (clm-00002 to clm-00004) further add a removal assistant with an engaging portion for recovery and a stretch restriction portion for suppressing axial stretching at a defined axial position relative to the valve support portions.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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