An instrument for use in electrosurgical procedures wherein coatings of two different materials are disposed on external surfaces. The first of these materials is selected to provide the principal insulating qualities desired, whereas the second is included to provide an indication of deterioration. The relative characteristics between the two coatings is selected so that when the visual appearance of the second coating progresses to a predetermined level, the insulating qualities of the first coating will still be satisfactory but approaching a point when the instrument has reached the end of its useful life, thus providing a ready and passive visual indication of the time when the instrument should be replaced.

This invention relates to electrosurgical electrodes and more particularly 
to such electrodes that have insulated coatings and which are reusable. 
BACKGROUND OF THE INVENTION 
As surgical knowledge and techniques have progressed, there has been a 
corresponding trend toward size reduction of surgical incisions and 
invasive instruments, thus decreasing patient trauma and contributing to 
rapidity of patient recovery. This has led to the practice of laparoscopic 
and other surgical procedures using small medical electrodes. The 
incidence of AIDS and other highly dangerous or fatal communicable 
diseases has highlighted the importance of using either discardable 
components or of thoroughly sterilizing those that are used more than 
once. While thorough sterilization may be more economical and cost 
effective for certain types of implements, there are others in which the 
harsh environments of sterilization (e.g., steam, autoclaving) may be 
excessively harmful or result in a reduction in useful life. Moreover, for 
some implements, repeated use itself may result in wear or deterioration. 
In protecting against communication of disease, a variety of 
electrosurgical techniques and implements have heretofore been proposed, 
illustrative of which are those described in U.S. Pat. No. 1,916,722 
granted to F. M. Ende Jul. 4, 1933; German Patent 2,404,764 granted to 
Bernard Weissman, et al. 19 Sep., 1974; PCT International Application U.S. 
Ser. No. 82/0084 filed by William S. Walker 25 Jan., 1982; and PCT 
International Application U.S. Ser. No. 91/05520 filed by Edwin Langberg 2 
Aug., 1991. According to proposals of these patents, multi-element 
implements have included reusable bodies with removable and disposable 
tips or electrodes. The main bodies or holders may be sterilized if needed 
and re-used, and the tips, blades or electrodes either discarded after one 
use or sterilized and re-used. However, there remain problems such as 
costs and time associated with sterilization and with optimization of use 
of the parts that make up an assembled instrument. For example, according 
to prior art proposals, the minimum expected useful life of an 
electrosurgical instrument has been identified and records kept of the 
length and type of use as well as the number of times the instrument has 
been sterilized, thus consuming time required to keep such records. 
Obviously, such procedures produce undesired overhead expense. In 
addition, where such an instrument is discarded after the expected minimum 
useful life has occurred, unless it is at the lower end of the "bell 
curve" of life expectancy, its remaining useful life, as well as the 
remaining useful lives of others of the instruments is not utilized, thus 
foreclosing use of remaining life of each individual instrument and 
leading to additional inefficiencies. Accordingly, there has continued to 
be a need for an improved electrosurgical instrument which includes an 
inexpensive and dependable way of identifying individual wear or 
deterioration so as to permit optimum use of each individual instrument 
while identifying a point beyond which use should be discontinued and the 
main body or holder replaced. 
BRIEF SUMMARY OF THE INVENTION 
The improved electrosurgical assembly according to the invention hereof 
includes an electrode holder for a disposable tip wherein a major surface 
or the entire exterior surface of the holder is coated with two coatings 
of different life expectancies. A first coating comprises the principal 
insulating coating for providing required electrical insulation and is 
characterized by exhibiting a relatively long life expectancy; whereas the 
second coating which may overlie at least a part of the first coating has 
a lesser life expectancy than that of the first coating and is used as a 
passive indicator of the remaining life of the first coating. Accordingly, 
when in use, a visual indication of the condition of the second coating 
provides a conservative indication of the likely remaining life of the 
first coating, i.e., the principal coating. In embodiments in which at 
least a part of the second coating overlies at least a part of the first 
coating, making the coatings of different colors, e.g., black and white, 
red and white, will make it visually apparent when a safe margin of 
remaining life for the first coating for each individual instrument has 
been reached, thus indicating the need for replacement. Moreover, by using 
different colors, damage due to physical marring becomes readily evident 
as, for example, revelation of the underlying color through scratches, 
nicks and the like. 
OBJECTS AND FEATURES OF THE INVENTION 
It is one general object of the invention to improve electrosurgical 
implements. 
It is another object of the invention to facilitate determination of 
determining remaining useful lives of such implements. 
It is still another object of the invention to increase utilization of 
remaining useful lives of insulated electrosurgical implements. 
It is yet another object of the invention to provide a passive way of 
visually determining the remaining life of each individual instrument. 
Accordingly, in accordance with one feature of the invention, an 
electrosurgical implement is constructed in a plurality of parts including 
an optionally disposable tip or blade attached to a doubly coated tip 
holding member, thereby facilitating repeated and safe use. 
In accordance with another feature of the invention, the doubly coated tip 
holding member includes at least partly overlying coatings of different 
life expectancies, thus facilitating passive visual identification of the 
condition of such coatings. 
in accordance with yet another feature of the invention, the coatings may 
be of different colors whereby deterioration of the outer coating may be 
readily detected when the color of the undercoating begins to show. 
In accordance with still another feature of the invention, through the use 
of the foregoing visual identification, counting the number of times the 
holding member has been sterilized or subjected to other 
deterioration-producing events may be eliminated, thus increasing 
efficiency in use. 
In accordance with yet a further feature of the invention, one of 
aforementioned coatings may be positioned over the other by 
shrink-wrapping, thus facilitating it positioning. 
These and other objects and features of the invention will be apparent from 
the following detailed description, by way of example of a preferred 
embodiment, with reference to the drawing.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Before proceeding to a detailed description, it may be helpful to consider 
the following definition of the word "Resposable". 
As used herein, "Resposable" means a device in which a part such as a tip 
or blade is optionally disposable and in which a portion such as a holding 
member for the optionally disposable part is reusable. 
Now turning to the drawing, and more particularly FIG. 1 thereof, it will 
be seen to be a perspective view of the electrosurgical blade according to 
the invention. There, a composite electrosurgical instrument is shown at 
10. It includes a main body 11 which is a holder for detachable tip 
portion 12 As illustrated, tip portion 12 includes an extension 13 
terminating in a curved hook 14. Of course, as will be evident to those 
skilled in the art, extension 13 could readily be a surgical blade or 
other surgical implement. At proximal end 15, there is included a 
conventional electrically conductive extension 16 which is provided for 
making conventional connections thereto. 
Now turning to FIG. 2, the composite electrosurgical instrument of FIG. 1 
is shown with detachable tip portion 12 detached. As will be evident to 
those skilled in the art, any of a variety of known ways may be employed 
to fasten the detachable tip 12 to the main body 11. However, in FIG. 2 
there is illustrated the provision of distal extension 11a which is 
adapted for insertion into a corresponding chamber 12a provided within tip 
portion 12. A locking lug 11b is provided as shown and engages a 
corresponding recess (not shown) within chamber 12a to provide for 
securely locking tip portion 12 to main body 11. 
As mentioned above, FIG. 3 is a sectional view taken along the section 
lines 3--3 of FIG. 2 and illustrates the preferred locations and 
relationships of the aforementioned two coatings that are identified 17 
and 18. At this point it should be noted that while in accordance with the 
preferred embodiment both coatings are insulating, such is not essential 
to the practice of the invention. For example, although the under coating 
17 should be insulating, the exterior coating 18 may be either essentially 
non-insulating or partially insulating in character so long as it changes 
in appearance with use as a function of the remaining life of the 
insulating coating 17 so that it represents a dependable visual indicator 
for the remaining life of the insulating coating 17. It should also be 
understood that although in the preferred embodiment, the exterior coating 
18 completely covers the insulating undercoating on the main body 11, such 
is not a requisite for practicing the invention hereof. 
Detachable tip 12 may be made of any of a variety of materials known by 
those skilled in the art to be suitable therefore. However, in the 
preferred embodiment hereof, such are seen to be silicone layer 19 
overlying stainless steel portion 20 from which stainless steel extension 
13 projects. Preferably covering extension 13 is a thin layer of 
fluorocarbon. 
Although, as mentioned above, a variety of conductive and insulating 
materials may be employed for the main body 11, the metallic portions are 
preferably comprised of stainless steel, the insulating under coating 17 
of polyetherimide, and the exterior coating 18 of polyvinylidene fluoride. 
These may be applied by a variety of techniques that are well known to 
those skilled in the art. 
In practicing the invention, the main body, e.g., body 11, may be used and 
sterilized repeatedly as, for example, by autoclave. After each 
sterilization, it is examined visually for signs of insulation 
deterioration which, as mentioned above, become evident through a 
deterioration of coating 18. Although such deterioration can be visually 
observed without resort to use of particular coloration, by making the 
exterior and interior coatings of highly contrasting colors, deterioration 
of the exterior coating will be facilitated and be dramatically evident 
through the presence of bleeding of the under color through that of the 
upper. In addition, nicks, scratches, abrasion and other discrete damage 
to the integrity of the insulation will also be dramatically evident. 
It will now be evident that there has been described herein an improved 
electrosurgical instrument providing for the passive progressive visual 
monitoring of the condition of electrical insulation thereon, and that it 
is easy and cost-effective to use, thus contributing to its attractiveness 
and desirability. 
Although the invention hereof has been described by way of a preferred 
embodiment, it will be evident that other, adaptations and modifications 
may be employed without departing from the spirit and scope thereof. For 
example, corresponding techniques could be extended to the detachable tip 
portions so as to render them reusable if desired. 
The terms and expressions employed herein have been used as terms of 
description and not of limitation; and thus, there is no intent of 
excluding equivalents, but on the contrary it is intended to cover any and 
all equivalents that may be employed without departing from the spirit and 
scope of the invention.