US3929138A

US3929138A - Sub-intimal dissector and methods for performing endarterectomies therewith

Info

Publication number: US3929138A
Application number: US380508A
Authority: US
Inventors: Eli Curi
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-07-18
Filing date: 1973-07-18
Publication date: 1975-12-30
Anticipated expiration: 1992-12-30

Abstract

A sub-intimal dissector and methods for performing endarterectomies therewith in which the said dissector comprises an elongated shape-retaining, bendable shaft, a dissecting tip on one end of the shaft, the tip being arcuate transverse to its longitudinal axis, a slightly forwardly convex leading edge of the tip smoothly merging with opposed side edges which taper rearwardly and inwardly to the shaft, the leading edge and the side edges being smoothly rounded between the top and bottom surfaces of the tip, the arcuately longest portion of the convex bottom of the tip being equal to approximately between one fifth and one third of the circumference of the artery upon which the instrument is employed; the method including the steps of longitudinally incising the artery to expose the diseased intima; transversely incising the artery to gain access to the interface of the intima and media; intruding the leading edge of the dissector tip intermediate the intima and media, passing the tip longitudinally along the artery intermediate to the intima and media with a steady forward pressure to detach the intima from the media by a wedging action for the length of the shaft inserted; withdrawing the dissecting tip to the position of entry and repeating the procedure with the remaining portions of the circumference of the artery; sequentially each newly dissected portion preferably being immediately adjacent to and contiguous with the previously dissected portion; incising the artery distially at a distance from the proximal incision no greater than approximately twice the length of the shaft and repeating the aforesaid dissecting procedure to disengage the intima from the media; and removing the dissected intima through one of the incisions.

Description

United States Patent Curi Dec. 30, 1975 SUB-INTIMAL DISSECTOR AND METHODS being arcuate transverse to its longitudinal axis, a FOR PERFORMING ENDARTERECTOMIES slightly forwardly convex leading edge of the tip THEREWITH smoothly merging with opposed side edges which taper rearwardly and inwardly to the shaft, the leading [76] inventor g ggg Court Roseland edge and the side edges being smoothly rounded between the top and bottom surfaces of the tip, the arcu- [22] Filed: July 18, 1973 ately longest portion of the convex bottom of the tip [21] Appl. No.: 380,508

Primary Examiner-Channing L. Pace Attorney, Agent, or FirmBain, Gilfillan & Rhodes [57] ABSTRACT A sub-intimal dissector and methods for performing endarterectomies therewith in which the said dissector comprises an elongated shape-retaining, bendable shaft, a dissecting tip on one end of the shaft, the tip being equal to approximately between one fifth and one third of the circumference of the artery upon which the instrument is employed; the method including the steps of longitudinally incising the artery to expose the diseased intima; transversely incising the artery to gain access to the interface of the intima and media; intruding the leading edge of the dissector tip intermediate the intima and media, passing the tip longitudinally along the artery intermediate to the intima and media with a steady forward pressure to detach the intima from the media by a wedging action for the length of the shaft inserted; withdrawing the dissecting tip to the position of entry and repeating the procedure with the remaining portions of the circumference of the artery; sequentially each newly dissected portion preferably being immediately adjacent to and contiguous with the previously dissected portion; incising the artery distially at a distance from the proximal incision no greater than approximately twice the length of the shaft and repeating the aforesaid dissecting procedure to disengage the intima from the media; and removing the dissected intima through one of the incisions.

8 Claims, 4 Drawing Figures U.S. Patent Dec. 30, 1975 3,929,138

FIG.1

SUB-INTIMAL DISSECTOR AND METHODS FOR PERFORMING ENDARTERECTOMIES THEREWITH BACKGROUND OF THE INVENTION In arterial sclerotic disease, the intima thickens until functional occlusion occurs. The solution lies in one of two expedients; the arterial graft or the arterial endarterectomy wherein the disease intima is removed or reduced to restore flow through the artery. The arterial graft has produced ambivalent and inconclusive results in the past.

Formerly, a conventional endarterectomy involved incising the artery for the full length of the occlusion; removing the obstructing intima and closing the incision by a running arterial suture. This procedure is sufficiently time consuming and traumatic so as to be unsuitable for the aged or infirm.

More recently, instruments have been devised to strip the diseased intima from the artery by the intrusion of a cutting instrument through a relatively small incision thereby avoiding the longitudinal incision extending for the length of the obstruction. The most widely accepted of such instruments is shown in U.S. Pat. No. 2,944,552 and comprises an annular cutting ring on one end of an elongated shaft. While the ring could be made in a variety of sizes, its use is frequently attended by either or both the failure to remove all of the intima or the cutting of the media. Additionally, even in the hands of the most experienced surgeons, there is very little feel or control of the instrument.

Another device which has received limited acceptance is the gas needle such as shown in U.S. Pat. No. 3,481,338 or 3,525,339. As in the case of the annular cutting ring, the gas needle frequently traumatizes the media, leaving a residue of the diseased intima and provides the surgeon with virtually no feel or control.

The present invention contemplates the stripping of the diseased intima by means of a wedging or separating action as distinguished from a cutting action by use of a smoothly rounded dissecting tip on the end of a bendable shaft.

Additionally, the present invention comtemplates stripping the intima usually in a continuous longitudinal segment by use of a dissecting tip, arcuately transverse to the longitudinal axis of the shaft to define an upper concave surface and a lower convex surface, the longest portion thereof extending for a distance equal to approximately one third to one fifth of the circumference of the artery and preferably one quarter of the circumference of the artery.

SUMMARY OF THE INVENTION A sub-intimal dissector comprising an elongated shaft, the shaft being bendable and having shape memory; a dissecting tip on the end of the shaft; the tip being arcuate transverse to its longitudinal axis to define a concave top surface and convex bottom surface extending between side edges; a slightly forwardly convex leading edge on the tip smoothly merging with the said opposed side edges; the opposed side edges tapering rearwardly and inwardly toward the shaft from a position slightly rearwardly of the leading edge; the arcuately longest portion of the said convex bottom surface extending along an arc transverse to the longitudinal axis of the tip approximtely one third to one fifth of the circumference of the artery upon which it is ing surface, substantially free from corrosive attack by A method for performing endartectomies comprising incising an artery to expose the interface between the intima and the media; intruding a dissecting tip intermediate the intima and the media; the dissecting tip being arc uate to define a concave top surface and a conforming convex bottom surface, the arc of the tip being generally transverse to the longitudinal axis of movement of the tip and extending a maximum distance equal to no more than approximately one third and no less than approximately one fifth of the circumference of the artery; passing the tip longitudinally through the artery from the said incision along the interface of the intima and media for a distance; withdrawing the tip to the incision; reintrud-ing the tip between the intima and media successively along arcuate paths contiguous to previous paths of movement of the tip for said distance until substantially the entire intima is disengaged from the media along said distance; and withdrawing the disengaged intima from the artery.

PREFERRED EMBODIMENT OF THE INVENTION The aforesaid objects and advantages as well as other objects and advantages may be achieved by use of the methods and instruments claimed herein preferred embodiments of which are described below.

A preferred embodiment of a sub-intimal dissector is illustrated in the drawings in which:

FIG. 1 is a top plan view of a sub-intimal dissector;

FIG. 2 is an end elevational view of the dissector shown in FIG 1;

FIG. 3 is a view in perspective of the sub-intimal dissector intruded between the intima and the media in an artery;

FIG. 4 is an end elevational cross sectional view of an artery showing arcuate planes of dissection between the media and the intima generated by use of the subintimal dissector illustrated in FIGS. 1, 2 and 3.

Referring now to the drawings in detail, the sub-intimal dissector comprises a smoothly rounded shaft 11 fabricated of a malleable metal so as to be limitedly resiliently flexible and bendable to retain a bent configuration yet sufficiently strong to transmit forces from a handle 12 through the shaft 11 to a dissecting tip 13 even when bent.

The handle 12 is preferably flat and sufficiently large to provide for fascicle manipulation although the particular shape of the handle is a matter of choice.

The dissecting tip 13 is formed on the end of the shaft 1 l opposite the handle 12 and comprises a concave top surface 14 and a generally conforming convex bottom surface 15 the arc of curvature being transverse to the longitudinal axis of the shaft 11 when the shaft 11 is axially straight.

The dissecting tip 13 is provided with a leading edge which is slightly forwardly convex in a direction opposite the shaft 11. The leading edge 16 smoothly merges with the opposed side edges 17 and 18 of the tip 13. The opposed side edges 17 and 18 preferably have a section, respectively 19 and 20 parallel to the longitudinal axis of the tip 13 for a relatively short distance and then a tapering section, respectively 21 and 22 which tapers rearwardly and inwardly to the shaft 11. The

shaft 1 1 is relatively rigid from the tip 13 rearwardly for a short distance to insure that the shaft 11 does not flex at the point of juncture between it and the tip 13.

The leading edge 16 and the side edges 17 and 18 of thetip 13 are smoothly rounded along their entire length between the concave top surface 14 and the convex bottom surface 15. The sub-intimal dissector is provided in varying sizes according to the size of the artery upon which it is to be employed. The most important relative dimension is the greatest arcuate distance along the concave-convex portions of the tip 13 which lie between the parallel portions 19 and of the side edges 17 and 18. The distance should be equal to between approximately one third to one fifth of the circumference of the artery upon which the dissector is to be employed; a distance equal to one quarter of said circumference being preferable.

The thickness of the tip 13 between the top surface 14 and the bottom surface 16 is between approximately 0.50 millimeter and 1.00 millimeter depending upon the size of the artery. It is also preferable to maintain the

parallel portions

19 and 20 of the side edges 17 and 18 as short as is functionally consistent with insuring separation of the intima from the media in order to minimize trauma to the media incident upon moving contact with the said side edges. Preferably, the

parallel side edges

19 and 20 should range between 0.5 cm and 1.0 cm depending upon the arc distance between the parallel side edges.

Previous instruments have employed cutting edges to separate the intima from the media. This has resulted in either trauma to the media or a severance of only a portion of the intima leaving a residue. Functionally, the object of the present invention is to wedge the intima from the media without substantial cutting action. To this end, the leading edge 16 and the side edges 17 and 18 are smoothly rounded between the top surface 14 and bottom surface 15. Additionally, the leading edge 16 is slightly forwardly convex and smoothly merges with the side edges 17 and 18 so as to avoid sharp edges, points or other abrupt configurational characteristics which tend to cut or induce trauma.

Still further, the tip 13 and the shaft 11 are provided with a lubricating cladding such as tetrafluoroethylene which is resistant to corrosive attack by body chemicals. Such a lubricating cladding enhances the wedging action of the tip 13 and reduces the damage of trauma to the media.

The following is a table of preferred sizes for the dissector according to artery size.

4 been previously established both proximal and distal control of the artery by clamping.

The arteriotomy is heldapart with various surgical devices.

A transverse incision is made at the arteriotomy to and through the intima surface to provide access to a clear, clean plane of dissection. Once an adequate plane of dissection has been developed between the intima and media, the sub-intimal dissector as described above is intruded between the intima and the media after being properly moistened with normal saline. When the instrument is moved downwardly along the artery, the intima is wedged away from the media along an arc equal to or slightly greater than the arc between the

parallel side portions

19 and 20 of the dissector tip. The dissector is forced gently forwardly in a relatively slow, steady and continuous fashion. The surgeon has a considerable degree of both control and feel as the dissector tip passes down the artery to detect any loss of the dissection paths.

After the dissector has been intruded preferably to the full length of the shaft, the dissector is withdrawn to the original incision. The dissector is then intruded between the media and intima in a paths adjacent to the plane initially disengaged.

This procedure is repeated for as many times as is necessary to develop paths of dissection around the circumference of the interface of the intima and the media.

After completion of the dissection around, the interface between the media and the intima, another arteriotomy is performed distially to the occlusion. The arteriotomy is made in the same fashion together with a transverse incision to gain access to the zone between the intima and the media.

The same procedure as described above is performed again pushing or forcing the dissecting tip forwardly along the artery until the first dissected portion is reached. The distance between the distal and proximal arteryectomies which includes the occluded portion is no greater than twice the length of the shaft of the sub-intimal dissector. Thus, the tip intruded from the proximal incision will engage the dissection made through the distal incision.

After the entire occluded intima has been dissected from the media the entire specimen is withdrawn by grasping with forceps and removing through one of the incisions.

In order to avoid damage to the media, the dissecting tip is provided with no sharp cutting edges and has TABLE I ARTERY SHAFT TIP OVERALL TIP SHAFT DIAMETER LENGTH THICKNESS LENGTH DIAMETER 2 mm 6 in. 0.50 mm 0.5 cm I mm 4 mm 6 in. 0.50 mm 0.8 cm 1 mm 6 mm 8-12 in. 1.00 mm 1.0 cm 1.5 mm 8 mm 8-12 in. 1.00 mm 1.2 cm 1.5 mm 10 mm 8-10 in. 1.00 mm 1.5 cm 1.5 mm

The method comprises the following steps.

An arteriotomy is performed by making an incision in the artery wall. The incision is longitudinal to the axis of the artery for a distance of from 2m 6 cm in length depending upon existing conditions and the size of the artery. This is to gain entrance to the internal portions of the artery. As in the usual arteriotomy there has 3 ,929 l 3 8 5 to be construed to include a dissection of the media from the adventitia.

The foregoing description is merely intended to illustrate an embodiment of the invention. The component c. a portion of the shaft immediately rearwardly of the tipis sufficiently rigid to prevent significant flexure at the junction of the tip and shaft, and

d. the tip is provided with an extremely low friction parts have been shown and described. They each may 5 Surface d have substitutes which may perform a substantially for performmg en artefectomles C msimilar function; such substitutes may be known as pnsmg' a. incising an artery to expose the interface between the intima and the media, 10 intruding a dissecting tip intermediate the intima and proper substitutes for the said components and may have actually been known or invented before the present invention.

What is claimed is;

1. A sub-intimal dissector comprising:

a. an elongated shaft, the shaft being bendable and having shape memory,

the media at said exposed interface,

c. wedging the intima and media apart by passing the dissecting tip longitudinally along said interface for a distance from said incision while avoiding damag- 5 ing the integrity of both the intima and media, b. a dissecting tip on one end of the shaft, (1. withdrawing the dissecting tip longitudinally to the c. the tip being arcuate transverse to its longitudinal incision,

axis to define a concave top surface and a convex e. reintruding the dissecting tip intermediate the inbQttQm urface extending between ide edges tima and media and the intima and media d. a slightly forwardly convex leading edge on the tip apart as affeSa1d successively along p f smoothly merging with the said opposed side edges, ous to Prevlous Paths of movement f l f e. the opposed side edges tapering rearwardl and said distance until substantially the entire intima 1s inwardly toward the shaft from a position slightly wedged f the fnedla m Sald dlstance and rearwardly of the leading edge f. withdrawing the disengaged intima from the artery. f. the arcuately longest portion of the said convex p gg for performing endarterectomles combottom i exteridmg aloilg arc transverse a. the procedure in accordance with claim 6 includto the longitudinal axis of the tip a distance equal to ing approxlmately one thud to fi h the clrcum' b. the steps of wedging the intima from the media by ference of an artery upon whlch to be passing along said interface a dissecting tip having p y and a concave top surface and a conforming convex the Sald lead1ng edge both Sald pp slde bottom surface; the arc of the said tip being generedges i g smoothly founded between the C011- ally transverse to the longitudinal axis of movement Ca tOp and Convex bottom urfa f the tipof the said tip and extending an arcuate distance 2. A sub-intima] dissector comprising, equal to approximately one third to one fifth of the a. the structure in accordance with claim 1, and circumference of the artery; the said tip having a b. the said tip being provided with an extremely low slightly forwardly convex leading edge smoothly f i ti f e merging with opposed side edges; the leading edges 3 A Sub intima1 dissector comprising and both side edges being smoothly rounded bea. the structure in accordance with claim 1, in which, tween the p and bottcfm Surfacesb. the said opposed side edges are parallel for a rela- A method for performmg endarterectomles tivel short distance immediatel rearwardl of the Pnsmg: Said llleading edge y y a. the procedure in accordance with claim 6, and the A Sub-intima dissector comprising b ir i i sifi the arter to ex ose interfaces between a. the structure in accordance with claim 1', in which, g y p b. a portion of the shaft immediately rearwardly of the top is sufficiently rigid to prevent significant flexure at the junction of the tip and shaft.

5. A sub-intimal dissector comprising,

the intima and media both distal and proximal to an occlusion, and

c. wedging the intima and media apart by passing the dissecting tip longitudinally along said interface as aforesaid from both the distal and proximal incia. the Structure in accordance with claim in which, sions in the direction of the opposite incision until b. the said opposed side edges are parallel for a relath ath of di engagement from the respective tively short distance immediately rearwardly of the incisions engage. said leading edge,

Claims

1. A sub-intimal dissector comprising: a. an elongated shaft, the shaft being bendable and having shape memory, b. a dissecting tip on one end of the shaft, c. the tip being arcuate transverse to its longitudinAl axis to define a concave top surface and a convex bottom surface extending between side edges, d. a slightly forwardly convex leading edge on the tip smoothly merging with the said opposed side edges, e. the opposed side edges tapering rearwardly and inwardly toward the shaft from a position slightly rearwardly of the leading edge, f. the arcuately longest portion of the said convex bottom surface extending along an arc transverse to the longitudinal axis of the tip a distance equal to approximately one third to one fifth of the circumference of an artery upon which it is to be employed, and g. the said leading edge in both said opposed side edges being smoothly rounded between the concave top and convex bottom surface of the tip.

2. A sub-intimal dissector comprising, a. the structure in accordance with claim 1, and b. the said tip being provided with an extremely low friction surface.

3. A sub-intimal dissector comprising, a. the structure in accordance with claim 1, in which, b. the said opposed side edges are parallel for a relatively short distance immediately rearwardly of the said leading edge.

4. A sub-intimal dissector comprising, a. the structure in accordance with claim 1, in which, b. a portion of the shaft immediately rearwardly of the top is sufficiently rigid to prevent significant flexure at the junction of the tip and shaft.

5. A sub-intimal dissector comprising, a. the structure in accordance with claim 1, in which, b. the said opposed side edges are parallel for a relatively short distance immediately rearwardly of the said leading edge, c. a portion of the shaft immediately rearwardly of the tip is sufficiently rigid to prevent significant flexure at the junction of the tip and shaft, and d. the tip is provided with an extremely low friction surface.

6. A method for performing endarterectomies comprising: a. incising an artery to expose the interface between the intima and the media, intruding a dissecting tip intermediate the intima and the media at said exposed interface, c. wedging the intima and media apart by passing the dissecting tip longitudinally along said interface for a distance from said incision while avoiding damaging the integrity of both the intima and media, d. withdrawing the dissecting tip longitudinally to the incision, e. reintruding the dissecting tip intermediate the intima and media and wedging the intima and media apart as aforesaid successively along paths contiguous to previous paths of movement of said tip for said distance until substantially the entire intima is wedged from the media along said distance, and f. withdrawing the disengaged intima from the artery.

7. A method for performing endarterectomies comprising: a. the procedure in accordance with claim 6 including b. the steps of wedging the intima from the media by passing along said interface a dissecting tip having a concave top surface and a conforming convex bottom surface; the arc of the said tip being generally transverse to the longitudinal axis of movement of the said tip and extending an arcuate distance equal to approximately one third to one fifth of the circumference of the artery; the said tip having a slightly forwardly convex leading edge smoothly merging with opposed side edges; the leading edges and both side edges being smoothly rounded between the top and bottom surfaces.

8. A method for performing endarterectomies comprising: a. the procedure in accordance with claim 6, and the steps of b. incising the artery to expose interfaces between the intima and media both distal and proximal to an occlusion, and c. wedging the intima and media apart by passing the dissecting tip longitudinally along said interface as aforesaid from both the distal and proximal incisions in the direction of the opposite incision until the paths of disengagement from the respective incisions engage.