Variable diameter sheath method and apparatus for use in body passages

Claim 2

A variable diameter sheath for insertion into a body passage from a point of ingress to the passage, said sheath comprising: a) a flexible tubular body of a generally uniform outside diameter insertable into the body passage through the point of ingress, said tubular body being elongate and pliable to conform to the shape of the body passage and having: (1) an open proximal end fixedly secured to a hub and a free open and unobstructed distal end; (2) an elongate portion extending from the hub to the free open distal end, which elongate portion is expansible to a relaxed outside diameter substantially equal to that of the passage, said elongate portion being: of a length sufficient to extend from and through the point of ingress to an area within said passage remote from the point of ingress; and formed by a thin self-supporting wall which serves to shield the passage from internal abrasion by objects passed through the sheath; (b) contraction means incorporated into the tubular body to diametrically contract the elongate portion while in the body passage responsive to axial distension of said portion; and, (c) motion imparting means to selectively axially distend the elongate portion while in the body passage.

Claim 3

A sheath according to claim 1 wherein said contraction means is adapted to: (a) diametrically expand the elongate portion to a diameter substantially equal to that of the body passage in response to axial contraction of the portion by the motion imparting means; and, (b) diametrically contract said portion to a diameter substantially less than that of said body passage in response to axial distension of the portion by the motion imparting means.

Claim 4

A sheath according to claim 1 wherein the contraction means is adapted to diametrically contract the elongate portion by substantially one-half or more in response to axial distension by said motion imparting means.

Claim 5

A sheath according to claim 1 wherein the motion imparting means comprises: (a) an elongate generally incompressible element extending along the tubular body for longitudinal movement relative thereto; and, (b) connecting means adapted to secure said element in compression imparting relationship to the body adjacent the open distal end thereof.

Claim 6

A sheath according to claim 4 wherein the elongate element extends over the full length of the tubular body and from the open proximal end thereof, said sheath further comprising grip means on the elongate element for manual gripping to impart compressive force to the element.

Claim 7

A sheath according to claim 5 wherein the hub comprises a tubular Y-shaped fitting, said fitting having a primary leg secured in communication with the open proximal end of the tubular body and secondary legs merging into communication with said primary leg, said elongate element extending from the open proximal end of the tubular body through the fitting.

Claim 8

A sheath according to claim 6 further comprising mutually engagable stop means on the elongate element and the fitting to limit the extent to which the elongate element can be extended relative to the tubular body.

Claim 9

A sheath according to claim 7 further comprising lock means to secure the mutually engagable stop means in an engaged condition.

Claim 10

A sheath according to claim 6 wherein the elongate element extends through one of the secondary legs of the fitting and wherein the sheath further comprises: (a) seal means on said one leg establishing a fluid tight seal between the fitting and the elongate element, while permitting movement of the element relative to the fitting; and, (b) valve means on the other of said secondary legs to close said other leg against fluid flow, while permitting instruments to be passed therethrough.

Claim 11

A sheath according to claim 4 wherein: (a) the elongate element comprises a tubular stylet extending longitudinally through the tubular body; and, (b) the connecting means comprises a wire extending slidably through the stylet and secured to the body adjacent the open distal end thereof.

Claim 12

A sheath according to claim 1 wherein the tubular body is elastomeric and the contraction means comprises a plurality of intersecting flexible generally inelastic filaments incorporated into the body, said filaments extending obliquely to the longitudinal axis of the body.

Claim 13

An elongate variable diameter sheath for insertion into a body passage from a point of ingress to the passage, said sheath comprising: (a) an impermeable elastomeric tubular body, said body being: insertable into the body passage through the point of ingress, elongate and pliable to conform to the shape of the body passage and having: (1) an open proximal end fixedly secured to a hub and a free open and unobstructed distal end; (2) an elongate portion extending from the hub to the free open distal end, which elongate portion has a longitudinal axis and is expansible to a relaxed outside diameter substantially equal to that of the passage, said elongate portion being: of a length sufficient to extend from and through the point of ingress to an area within said passage remote from the point of ingress; and formed by a thin self-supporting wall which serves to shield the passage from internal abrasion by objects passed through the sheath; (b) intersecting flexible generally inelastic filaments incorporated into the body and extending obliquely of the longitudinal axis of the elongate portion to diametrically contract the elongate portion while in the body passage responsive to axial distension of said portion; and, (c) motion imparting means to selectively axially distend the elongate portion and axially contract said portion while in the body passage.

Claim 14

An elongate variable diameter sheath for insertion into a body passage from a point of ingress to the passage, said sheath comprising: (a) an impermeable elastomeric tubular body, said body being: insertable into the body passage through the point of ingress, elongate and pliable to conform to the shape of the body passage and having: (1) an open proximal end fixedly secured to a hub and a free open and unobstructed distal end; (2) an elongate portion extending from the hub to the free open distal end, which elongate portion has a longitudinal axis and is expansible to a relaxed outside diameter substantially equal to that of the passage, said elongate portion being: of a length sufficient to extend from and through the point of ingress to an area within said passage remote from the point of ingress; and formed by a thin self-supporting wall which serves to shield the passage from internal abrasion by objects passed through the sheath; (b) intersecting flexible generally inelastic filaments incorporated into the body and extending obliquely of the longitudinal axis of the elongate portion to diametrically contract the elongate portion while in the body passage responsive to axial distension of said portion; and, (c) motion imparting means to selectively axially distend the elongate portion and axially contract said portion while in the body passage.

Claim 15

A sheath according to claim 12 wherein the motion imparting means comprises: (a) an elongate generally incompressible element extending along the body for longitudinal movement relative thereto; and, (b) connecting means adapted to secure said element in compression imparting relationship to the body adjacent the open distal end thereof.

Claim 16

A sheath according to claim 13 wherein said elongate element extends from the open proximal end of the tubular body through the hub and further comprising mutually engageable stop means on the elongate element and the hub to limit the extent to which the elongate element can be extended relative to the tubular body.

Claim 17

A sheath according to claim 14 further comprising lock means to secure the mutually engagable stop means in an engaged condition.

Claim 18

A sheath according to claim 14 wherein: (a) the hub is Y-shaped and has a primary leg secured in communication with the open proximal end of the tubular body and secondary legs merging into communication with the primary leg and wherein the elongate element extends through one of the secondary legs of the hub; and, (b) the sheath further comprises: (1) seal means on said one leg establishing a fluid tight seal between the hub and the elongate element, while permitting movement of the element relative to the hub; and, (2) valve means on the other of said secondary legs to close said other leg against fluid flow, while permitting instruments to be passed therethrough.

Claim 19

A sheath according to claim 13 wherein the elongate element extends over the full length of the tubular body, further comprising grip means on said element for manual gripping to impart compressive force to the element.

Claim 20

A sheath according to claim 13 wherein: (a) the elongate element comprises a tubular stylet extending longitudinally through the sheath; and, (b) the connecting means comprises a wire extending slidably through the stylet and secured to the body adjacent the open distal end thereof.

Claim 21

A sheath according to claim 12 wherein the open distal and extends obliquely to the longitudinal axis of the elongate portion and is bounded by a pliable elastomeric extension.

Claim 24

A method according to claim 20 wherein the tube is distended by: (a) extending an elongated stylet along the tube; (b) engaging the stylet with the tube closely adjacent the distal end thereof; and, (c) applying compressive force to the stylet while restraining the proximal end to stretch the tube.