Shear force gauge and method and apparatus for limiting embolectomy shear force

Claim 2

A shear force gauge for applying controlled tension to an elongate wire or catheter element, said gauge comprising: first means to grip the element; second means secured to the first means to apply force thereto and tension to an element gripped thereby; and third means operatively associated with the second means to sense the force applied to the first means through the second means.

Claim 3

A shear force gauge according to Claim l wherein the first means is slidable relative to the element and grips the element through frictional engage­ment therewith, said gauge further comprising means to adjust the degree of frictional engagement between the first means and the element to permit the first means to slip relative to the element to limit the ten­sion applied to the element.

Claim 4

A shear force gauge according to Claim 2 wherein the first means comprises an annular clamp through which the element extends and means selectively compress the clamp into engagement with the element with varying degrees of force.

Claim 5

A shear force gauge according to Claim l wherein: the first means comprises a tube through which the element is extended; the second means is slid­ably received on said tube and secured to the first means through a deflectable spring; and the third means comprises a gauge to measure movement of the second means relative to the first means.

Claim 6

A shear force gauge according to Claim 4 wherein the gauge comprises indicia marked along the length of the tube and a follower on the second means alignable with said indicia.

Claim 7

A shear force gauge according to Claim 4 wherein the first means is slidable relative to the element and grips the element through frictional engage­ment therewith, said gauge further comprising means to adjust the degree of frictional engagement between the first means and the element to permit the first means to slip relative to the element to limit the ten­sion applied to the element.

Claim 8

A shear force gauge according to Claim 6 wherein the first means comprises an annular clamp through which the element extends and means selectively compress the clamp into engagement with the element with varying degrees of force.

Claim 9

An improved embolectomy apparatus com­prising: an elongate catheter having a through lumen; a balloon secured to the catheter proximate one end thereof in sealed fluid communication with the lumen; a syringe secured to the catheter proximate the other end thereof in sealed fluid communication with the lumen; first means carried by the catheter to selectively grip the catheter; second means secured to the first means to apply force thereto and tension to a catheter gripped thereby; and third means operatively associated with the second means to sense the force applied to the first means through the second means.

Claim 10

An improved embolectomy apparatus com­prising: an elongate catheter having a through lumen; a balloon secured to the catheter proximate one end thereof in sealed fluid communication with the lumen; a syringe secured to the catheter proximate the other end thereof in sealed fluid communication with the lumen; first means carried by the catheter to selectively grip the catheter; second means secured to the first means to apply force thereto and tension to a catheter gripped thereby; and third means operatively associated with the second means to sense the force applied to the first means through the second means.

Claim 11

An improved embolectomy apparatus according to Claim 8 wherein the first means is slidable relative to the catheter and grips the catheter through frictional engagement therewith, said apparatus further comprising means to adjust the degree of frictional engagement between the first means and the catheter to permit the first means to slip relative to the catheter to limit the tension applied to the catheter.

Claim 12

l0. An improved embolectomy apparatus according to Claim 9 wherein the first means comprises an annular clamp through which the catheter extends and means to selectively compress the clamp into engagement with the catheter with varying degrees of force.

Claim 13

An improved embolectomy method comprising: providing an elongate catheter having a through lumen and a balloon proximate the distal end thereof in sealed fluid communication with the lumen; directing said catheter through a body passage and past an embolus in the passage; inflating the balloon by applying fluid pressure thereto through the catheter lumen; withdrawing the catheter from the body passage by gripping the catheter and applying tension thereto; continuously monitoring the tension applied to the catheter during such withdrawal;> and controlling the withdrawal force applied to the catheter to maintain the tension applied to the catheter within a predetermined limit.

Claim 14

An improved embolectomy method comprising: providing an elongate catheter having a through lumen and a balloon proximate the distal end thereof in sealed fluid communication with the lumen; directing said catheter through a body passage and past an embolus in the passage; inflating the balloon by applying fluid pressure thereto through the catheter lumen; withdrawing the catheter from the body passage by gripping the catheter and applying tension thereto; continuously monitoring the tension applied to the catheter during such withdrawal;> and controlling the withdrawal force applied to the catheter to maintain the tension applied to the catheter within a predetermined limit.

Claim 15

An improved embolectomy method according to Claim ll wherein the catheter is gripped through a frictional connection which maintains the withdrawal force applied to the catheter beneath a predetermined level.