CA1124155A - Instrument for performing endarterectomy - Google Patents

Abstract

A B S T R A C T
There is provided an instrument for performing endarterectomy which includes a reaming head, a handle, and a resilient wire connecting the two. The head consists of a straight rod-like shaft rounded at its leading end, and a rounded long-pitch helical thread encircling the shaft.

Description

INSTRUMENT FOR PERFORMING ENDARTERECTO~Y
l~his invention relates generally to endarterec-tomy procedures, and has to clo partlcularly with the provision of a reaming instrument adapted to perform endarterectomy (reaming out) of blood vessels.
While the instrument disclosed and claimed herein finds particular use during the operation known as coronary artery bypass graft, it will be appreciated from what follows that the instrument can find use in a number of operational situations, not necessarily involv-ing heart surgery.
It is an aspect of this invention to provide a simple, easily used manual instrument by which endarterec-tomy can be safely and effectively performed by the surgeon.
Accordingly, this invention provides an instru-ment for performing endarterectomy on blood vessels, comprising:
a reaming head which includes a straight rod-like ~o shaft rounded at one end, and a rounded helical thread encircling the shaft, a handle portion, and a resilient wire secured at its one end to the other end of the shaft in coaxial fashion, and secured at ~5 its other end to the handle portion.
Two embodiments of this invention are illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:
Figure 1 is an exploded, perspective view of a first embodiment of this invention;
Figure 2 is a view, to a smaller scale than Figure 1, of the instrument in its closed condition; and Figure 3 is a view, to a la~r scale, of the reaming head of the second embodiment of this invention.
In Figure 1, an instrument 10 for performing endarterectomy on blood vessels in seen to include a reaming head 12, a handle portion 14, and a resilient wire 16.
The reaming head 12 includes a straight rod-like shaft 18 which is rounded at its forward (rightward) end, and which has an integral helical thread 20 encircling the shaft 18. More particularly, the helical thread 20 has an angle of about 45 with respect to the axis of the shaft 1~, which in the embodiment shown in-Figure 1 causes the helical thread to have a pitch greater than its own outside diameter. It will be appreciated that it is not considered essential that the helical thread have a pitch greater than its own outside diameter, nor is it essential that the thread angle be at least 45 with respect to the axis o the shaft 18. However, a certain "pulled out" configuration of the thread is preferred in the conscruction of the instrument described herein.
In the embodiment shown in Figure 1, the helical thread 20 extends only as far as the location identified by the numeral 22, leaving the forward or rightward portion of the shaft 18 unthreaded. This is considered to be of advantage in a preferred form of the invention,`in that it allows the surgeon to easily insert the reaming'head 12 into the opened blood vessel, prior to reaming. More specifically, it is considered of advantage, in a pre~erred ~5 form of the invention, that the shaft 18 have an unthreaded forward section at least as long as the pitch of the helical thread 20.
Completing the overall assembly, although not part of the instrument during an operation procedure, is an elongated tube 24 which is internally threaded at the leftward end 25, and is thus adapted for threaded engage-ment with external threads 27 which are provided on the handle portion 18 adjacent the connection between the handle portion 14 and the wire 16. More specifically, the handle portion 14 has a reduced diameter throat identified by the numeral 29, the throat 29 being situated between the threads 27 and a main barrel 30 of the handle portion 14. Forwardly or rightwardly of the

2~5 external threads 27 is a forwardly converging conical portion 32 endlng in a projection 33 to which the wire 16 is silver soldered or otherwise securely affixed.
The other end of the wire 16 is connected, again by silver soldering or some equivalent secure means, in a coaxial fashion to one end of the shaft 18 (the end opposite the unthreaded end as seen in Figure 1).
It is considered important that the reaming head 12 be rounded at its leading end (the end of the unthreaded portion), so as not to catch or cut the internal walls of a blood vessel being reamed out. Likewise, it is con-sidered important that the helical thread 20 also be rounded, again to avoid cutting or scratching the internal walls of the blood vessel.
Figure 2 shows the two separate parts of the instrument of Figure 1 in "closed" engaged position. The open-ended tube 24 is long enough to receive the entire length of the wire 16 plus the reaming head 12, without the latter projecting out the rightward end 35 of the tube 24.
Figure 3 shows a reamin~ head 36 of slightly different configuration, constituting the second reaming head embodiment of this invention. In Figure 3, the reaming head 36 again has an unthreaded forward portion 38, but has a greater number of convolutions in the helical thread 40. Again, the forward end 42 of the reaminy head 36 is rounded, as is the profile of the thread 40 itself.
The following specific dimensions ofparticular instruments-built and satisfactorily tested over a large number of operations are given only by wav of illustration, and it is not considered that the inven-tion is limited to these or any other specific dimenions.
Firstly, in the prototypesconstructed and tested, all of the materials were of stainless steel, including the handle, the wire and the reaming head.
The wire size was 15 thousandths of an inch, and the length of the reaming head was in the region of ~4-1 centimeter. In actual fact, three different sizes of reaming head were built and tested, all of them having the same length of ahout 1 centlmeter, but having different diameters. The diameter can be expressed in terms of the pitch diameter of the helical thread, together with the thread height (i.e. the radial dimension of the thread from its inner diametex to its outer diameter).
The three reaming heads constructed had thread pitch diameters of 1 millimeter, 1.5 millimeter and 2 milli-meters respectively. The thread height in each case wasbetween 10 and 12 thousandths of an inch. It is expected that pitch diameters of 0.5 mm, and also sizes larger than 2 mm will also find use in operational situations. For example, pitch diameters up to 3~ millimeters, along with a thread height between 10 and 12 thousandths of an inch, could well be useful in operations involving particularly larye vessels of the body.
The threads utilized in the embodiments built and tested all had a pitch corresponding to about 10 threads per inch. The threads were all radiused or rounded, and of course the "nose" of the shaft of the reaming head was also rounded.

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Claims (4)

CLAIMS:

1. An instrument for performing endarterectomy on blood vessels, comprising:
a reaming head which includes a straight rod-like shaft rounded at one end, and a rounded helical thread encircling the shaft, a handle portion, and a resilient wire secured at its one end to the other end of the shaft in coaxial fashion, and secured at its other end to the handle portion.

2. The instrument claimed in claim 1, in which the handle portion is elongated and is externally threaded adjacent its connection with the wire for threaded engagement with an internally threaded tube adapted to receive the wire and reaming head and to protect the same.

3. The instrument claimed in claim 1 or claim 2, in which the helical thread is integral with the shaft and has a pitch greater than its own outside diameter.

4. The instrument claimed in claim 1 or claim 2, in which the reaming head has an unthreaded forward section at least as long as the pitch of the helical thread.