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BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to tympanoplasty, or the surgical
reconstruction of the middle ear which restores or replaces the sound
conducting mechanism. More particularly, the present invention relates to
an improved method for preparing an ossicular replacement prosthesis, an
improved ossicular replacement prosthetic device and a punch mechanism for
removing tragal cartilage and applying the removed cartilage to the
prosthetic device before the device is implanted in a patients ear.
2. Discussion of the Prior Art
Under normal circumstances, sound waves which strike the tympanic membrane
(i.e. the ear drum) are transmitted through the ossicular chain of the
middle ear (i.e. the malleus, the incus and the stapes) to a membrane
which is stretched across the oval window of the inner ear. In this
regard, reference should be made FIG. 1 of the accompanying drawings
wherein a drawing of the inner ear is provided to facilitate an
understanding of the structure involved. Behind the oval window membrane
is fluid which fills the cochlea of the inner ear where the transmitted
vibrations are translated into neural impulses. Sound transmission through
the ossicular chain can become interrupted or non-functional due to a
variety of diseases or injuries to the middle ear. Surgical reconstruction
of the middle ear to restore or replace the sound conductive mechanism
therethrough is called tympanoplasty. In cases where portions of the
ossicles have become erroded, lost or otherwise non-functional, a plastic
prosthetic device may be placed between the tympanic membrane and the head
or footplate of a mobile stapes. An example of such prosthetic device may
be found in U.S. Pat. No. 3,909,852 (Homsy). If the footplate is not
mobile, the prosthetic device may be implanted between the drum and a
graft placed over a drilled-out or fenestrated footplate. In either case,
the ultimate goal is the restoration of the sound conduction function from
the tympanic membrane to the oval window by means of a prosthetic device
which replaces some or all of the ossicles. In FIG. 4a there is
illustrated a typical prior art prosthetic device 10 implanted between the
tympanic membrane and the head of the stapes. In FIG. 4b a typical prior
art prosthetic device 11 is shown implanted between the tympanic membrane
and the footplate of the stapes.
Ossicular replacement prosthetic devices take a variety of forms and are
selected for implantation in accordance with the nature of the pathology
and anotomical peculiarities of the patient. The present invention relates
to only two types of such prosthetic devices, namely: the total ossicular
replacement prosthesis (TORP) and the partial ossicular replacement
prosthesis (PORP). The TORP, as its name implies, replaces the entire
ossicular chain and fits between the tympanic membrane and the footplate
(or fenestrated footplate) of the stapes, such as the prosthetic device 11
of FIG. 4b. This prosthetic device 11 is illustrated in greater detail in
FIG. 2b and is shown to include a cylindrical shaft portion 14 terminating
at one end in a circular flange 15 which faces the typanic membrane when
the prosthesis is implanted. The opposite end of shaft 13 rests against
the foot plate of the stapes when implanted. The PORP fits between the
tympanic membrane and the head of a functioning stapes as illustrated by
prosthetic device 10 illustrated in FIG. 4a. Prosthetic device 10 is
illustrated in greater detail in FIG. 2a and includes a shaft 17 which
terminates at its tympanic membrane-facing end in a flange 19 similar in
configuration to flange 15 of prosthetic device 11. The opposite end of
shaft 17 is provided with a generally cylindrical part extending
longitudinally of the shaft so as to be able to receive the head of the
functioning stapes. Each of prosthetic devices 10 and 11 take a variety of
more specific configurations such as illustrated in FIGS. 3a through 3h,
depending upon the particular anotomical features of the patient. The
devices illustrated in FIGS. 3a, 3b, 3c and 3d represent PORP devices; the
prosthetic devices illustrated in FIGS. 3e, 3f, 3g and 3h represent TORP
devices. All of these prosthetic devices are typically constructed from a
plastic material, or combination of plastic materials, that can be readily
tolerated by the human body. Some of these plastics are porous and
purposely designed to promote tissue ingrowth in order to stabilize the
implant, much in the manner described in the aforementioned Homsy Patent.
In all instances, however, the material employed must be capable of
conducting sound from the tympanic membrane to the head or foot plate of
the stapes.
A major problem associated with the utilization of the prosthetic devices
illustrated in FIGS. 3a through 3h is the tendency toward rejection and
subsequent extrusion (or perforation) of the implant when the plastic
surface of the prosthesis comes into contact with the tympanic membrane or
a graft which replaces this membrane. It has been found, in the prior art,
that this problem can be alleviated by placing a thin slice of cartilage
between the prosthesis and the tympanic membrane. This is illustrated in
FIG. 5a for the PORP device and in FIG. 5b for the TORP device. In order
to obtain this cartilage a surgeon must first make an incision in the
leading edge of the tragus to expose the cartilage and its outer covering,
the perchondrium. A piece of tragus is then removed with a scalpel making
sure that the perchondrium is left intact. The cartilage is then trimmed
and sewn onto the prosthesis as illustrated in FIG. 6a.
The cartilage is sewn onto the prosthesis in a manner which will bring the
perichondrium of the finished implant in touch with the tympanic membrane.
The cartilage is then trimmed to fit the dimensions of the flange.
This trimming procedure is illustrated in FIG. 6b and the final prosthesis,
with the properly trimmed slice of cartilage, is illustrated in FIG. 6c.
There are numerous problems associated with the technique described above
for obtaining the tragal cartilage and attaching it to the prosthesis.
Since the procedure is performed by hand, it is a relatively
time-consuming process which requires considerable dexterity on the part
of the surgeon. In addition, although this technique is preferable to
methods which do not use cartilage, the end product still interposes
suture material between cartilage and the tympanic membrane or ear drum
which could lead to rejection and extrusion. Further, since is is trimmed
with a scalpel, the resulting cartilage plug has sharp edges which may
lead to perforation of the ear drum. Finally, the suture employed for this
procedure does not dissolve and consequently is always in contact with the
drum, thereby promoting infection and utilmate extrusion.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to improve
tympanoplastic techniques so as to eliminate the disadvantages and
problems set forth above.
It is another object of the present invention to provide an improved method
for obtaining a cartilage plug from a patient's tragus and applying that
plug to a prosthetic device for implantation into the middle ear.
A further object of the present invention is to provide a cartilage punch
capable of simply and effectively removing tragel cartilage in the form of
a plug having uniform thickness, retaining that plug after removal, and
then applying the plug to a prosthetic device.
Another object of the present invention is to provide an improved
prosthetic device for use in replacing some or all of the ossicles in a
patient's middle ear and which is capable of self-attachment to a
cartilage plug without the use of suture material, or the like.
One of the objects of the present invention is to provide a method for
preparing an ossicular replacement prosthesis in a patient's ear by
removing a plug of tragal cartilage from the patient's ear with a hollow
reciprocal cutting tool by forcefully translating the cutting tool toward
a stage when the tragal cartilage is disposed between the cutting tool and
the stage, retaining the removed plug in the cutting tool, placing the
prosthesis on the stage, forcefully urging the retained cartilage plug
against the prosthesis on the stage, and attaching the prosthesis to the
plug in response to the forceful urging of the plug against the stage.
It is another object of the present invention to provide an ossicular
replacement prosthesis adapted for in vivo implantation between the
tympanic membrane and oval window of a patient's ear comprising a surface
adapted to have a cartilage plug secured thereto to be disposed between
the surface and the patient's tympanic membrane, and an attachment means
for engaging the cartilage plug in response to forceful application of the
plug to the prosthesis in a direction generally perpendicular to the
prosthesis surface.
A still further object of the present invention is to provide a cartilage
punch for exising a cartilage plug of uniform thickness from a cartilage
mass in vivo and including a housing member with an elongated passage
defined therein and a cutting opening at one end thereof, a cutting
plunger secured in the housing member for longitudinal reciprocating
movement in the elongated passage, wherein the cutting plunger has an
annular cutting end disposed to to be selectively projected out through
the cutting end of the housing member, an anvil secured to the housing
member and having a stage surface oriented generally perpendicular to the
longitudinal reciprocating movement of the cutting plunger, the stage
surface being translatable in a direction parallel to the direction of
reciprocating movement of the plunger so as to selectively position the
stage surface with respect to the housing, and means for selectively
forcefully translating the cutting plunger toward the cutting opening to
force the annular cutting end of the plunger through the cutting opening
so as to cut a cylindrical plug of cartilage and retain that plug within
the annular cutting end.
In accordance with the present invention, a cartilage punch is provided in
a syringe-like configuration with a hollow core terminating in an annular
cutting tip. An anvil assembly includes a stage surface disposed
externally of the housing and toward which the cutting tip is selectively
translatable. The stage surface can be adjusted at selected distances from
the housing to permit insertion of the tragal cartilage mass between the
housing and stage surface. A cartilage plug is obtained from the inserted
tragal cartilage mass by forcing the cutting tip toward the stage surface
so as to penetrate the tragal cartilage mass and cut a plug therefrom
which is retained within the annular cutting tip. Retraction of the
cutting tip permits removal of the cartilage mass, after which time a
prosthetic device may be inserted onto the stage surface for eventual
forceful engagement between the retained cartilage plug and the flange or
similar portion of the prosthetic device.
A core rod is provided and is insertable into the hollow core of the
cutting member in order to extrude unnecessary cartilage portions of the
retained plug, which portions can then be removed by means of a scalpel,
or the like. The tip of this rod may also be employed to stabilize the
remaining cartilage plug when it is forcefully pressed against the
prosthetic device for attachment thereto.
An improved prosthetic device is provided whereby the flange or like
surface thereof attaches directly to the cartilage plug in response to the
forceful urging of that plug against the prosthetic device. Engagement of
the plug at the prosthetic device may be effected by proejctions which
penetrate the cartilage plug, projections which partially enclose the
cartilage plug or by adhesive attachment of the cartilage plug to the
prosthetic device. The stage surface of the cartilage punch is contoured
to receive the prosthetic device to facilitate transfer of the cartilage
plug to that device.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and still further object, features and advantages of the present
invention will become apparent upon consideration of the following
detailed description of specific embodiments thereof, especially when
taken in conjunction with the accompanying drawings wherein like numbers
in the different figures represent the same elements, and wherein:
FIG. 1 is a diagrammatic illustration of a human inner ear;
FIGS. 2a and 2b are views in perspective of prior art partial ossicular
replacement prosthesis and total ossicular replacement prosthesis devices,
respectively;
FIGS. 3a through 3h inclusive, are respective views in perspective of prior
art ossicular replacement prosthetic devices;
FIGS. 4a and 4b are diagramatic representations of prior art ossicular
replacement prosthetic devices impalnted in the middle ear of a patient;
FIGS. 5a and 5b are views similar to FIGS. 4a and 4b, respectively, but
showing a prior art cartilage slice attached to the prior art prosthetic
devices to abut the tympanic membrane when implanted;
FIGS. 6a through 6c illustrate a prior art prosthetic device and the method
of attachment thereto of a cartilage slice in accordance with the prior
art;
FIG. 7a is a view in perspective of a cartilage punch constructed in
accordance with the present invention;
FIG. 7b is a plan view in partial section of the cartilage punch of FIG.
7a;
FIG. 7c is a view similar to FIG. 7b but showing the cartilage punch
deployed so as to receive tragel cartilage prior to a cutting procedure;
FIG. 7d is a view similar to FIG. 7b showing tragel cartilage properly
inserted into the cartilage punch immediately prior to a cutting
procedure;
FIG. 7e is a view similar to FIG. 7b showing the cartilage punch in the
process of cutting a cartilage plug from the inserted tragel cartilage;
FIG. 7f is a view similar to FIG. 7b showing the cartilage punch after a
plug of cartilage has been removed from the tragel cartilage mass;
FIG. 7g is a view of the cartilage punch of FIG. 7b showing a trimming
operation of the removed cartilage plug after an excess portion of the
plug has been extruded from the cutting member;
FIGS. 8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h, 8i, 8j, 8k, 8l, 8m, 8n and 8o are
respective view in perspective of ossicular replacement prosthetic devices
constructed in accordance with the present invention;
FIGS. 9a and 9b are partially diagramatic views in plan showing partial
(FIG. 9a) and total (FIG. 9b) ossicular replacement prosthetic devices in
conjunction with cartilage plugs to be attached thereto;
FIG. 10a is a view in perspective of a modified version of a partial
ossicular replacement prosthetic device constructed in accordance with the
principles of the present invention;
FIG. 10b is a total ossicular replacement prosthetic device constructed in
accordance with the principles of the present invention;
FIGS. 11a through 11f show sucessive stages in the procedure whereby a
prosthetic device in accordance with the present invention is inserted
into the cartilage punch assembly, and a cartilage plug previously cut and
retained is secured to the prosthetic device; and
FIGS. 12a through 12e are respective views in section of different
configurations of the stage surface of the cartilage punch of the present
invention arranged to receive differently configured ossicular replacement
prosthetic devices of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring specifically to FIGS. 7a and 7b of the accompanying drawings, a
cartilage punch 20, constructed in accordance with the principles of the
present invention, takes the form of a syringe-like device having a
housing member 21 with an elongated bore or passage 22 extending entirely
therethrough. Housing member 21 has an opening at its rear or proximal end
which communicates with elongated passage 22 so that a plunger member 23
can be received in the passage. The opposite end of the housing member 21
is provided with a cutting opening 24 which also communicates with the
elongated passage 22. Plunger 23 is selectively translatable
longitudinally within the elongated passage 22 and includes an internal
longitudinally-extending hollow core 25 extending between its longitudinal
ends. One end of the plunger 23, namely the proximal end, includes an
enlarged diameter flange 26 for suitable engagement by a user's thumb in
forcing the plunger into the housing member 21. The opposite end of the
plunger terminates in an annular cutting tip 27 which, by virtue of the
selective translation of plunger 23 in passage 22, can be selectively
projected out from and withdrawn into passage 22 at cutting opening 24 in
the housing member. A vent opening is provided in the periphery of plunger
23 to permit the hollow interior 25 of plunger 23 to communicate with
ambient air. Vent opening 28 is preferably located, in the manner
illustrated, adjacent the actuator flange 26. A similar flange 29 is
provided at the proximal end of housing member 21 to serve as a stop by
abutting flange 26 in the fully inserted position of the plunger 23. A
core rod 30 is selectively insertable longitudinally into the hollow
interior region 25 of plunger 23. As will be described subsequently in
greater detail, the purpose of core rod 30 is twofold: first, the core rod
is used to extrude excess portions of cartilage which have been cut and
retained by cutting tip 27; second, the core rod stabilizes the retained
cartilage when the cartilage is being attached to a prosthetic device.
An anvil or stage assembly for the cartilage punch includes a track
assembly extending longitudinally along one side of housing member 21. An
elonagated runner 32 is slidably engaged in the track assembly 31 and
includes a stage member 33 secured at its distal end. Stage member 33 is
disposed forwardly of the cutting opening 24 of housing member 21 and is
displaceable at variable distances from that cutting opening by sliding
runner 32 in the track assembly 31 to the desired position. A stage
surface 34 of the stage member 33 is oriented substantially perpendicular
to the direction of longitudinal motion of plunger 23 in housing 21 so as
to squarely face the cutting opening 24. A set screw 35 is secured to the
runner 32 so as to be extendable transversely therethrough into the track
assembly 31 for locking the runner in place at various locations along the
length of the housing.
The plunger is normally biased in its retracted position wherein cutting
tip 27 is withdrawn into the housing. This bias is effected by a spring 36
having one end secured to the housing and the other end secured to the
plunger internally of the housing and having its intermediate portion
helically wound about the plunger.
The housing is provided with a grip 37 extending radially outward from the
housing at one side thereof which is opposite the side on which the track
assembly is defined. A corresponding grip or trigger member 38 is secured
to runner 32 to facilitate translation thereof in the track 31. In
addition, grip members 37 and 38 facilitate the grabbing of the housing
with the user's fingers while the plunger is depressed into the housing by
means of the user's thumb applied to flange 26, much in the manner of the
actuation of a syringe.
In operation of the cartilage punch, the core rod 30 is first removed from
the hollow interior 25 of plunger 23 in the manner illustrated in FIG. 7c.
In this regard, the core rod 30 is exteriorly threaded at a location
adjacent its proximal end so as to engage an internally threaded portion
of flange 26. This threaded engagement is disconnected in order to remove
the rod. Once rod 30 has been removed, stage member 33 is extended
relative to cutting opening 24 by loosening the set screw 35 and sliding
runner 32 as necessary in the track assembly 31. The tragal cartilage is
then inserted between the cutting opening and the stage surface 34. With
the tragal cartilage properly positioned as aforesaid, runner 32 is
retracted in slide member 31 to tightly engage opposite sides of the
tragal cartilage mass between the cutting opening 24 and the stage surface
34 as illustrated in FIG. 7b. The set screw is then tightened to maintain
this engagement of the tragal cartilage mass. With the cartilage mass thus
set in the punch, the plunger 23 is pushed to force the annular cutting
end 27 of the plunger out through cutting opening 24 toward surface 34. As
a result, the annular cutting end 27 penetrates the tragal cartilage mass
to cut a plug from the cartilage which is forced inside the forward end of
the hollow interior end 27 of the plunger as illustrated in FIG. 7e. Once
the cartilage has been punched, the plunger is released so as to be forced
backward by the urging of bias spring 36 to the position illustrated in
FIG. 7f.
The resulting cartilage plug which is equal in length to the thickness of
the tragal cartilage is entirely retained in the bore of the cutting
assembly
As illustrated in FIG. 7g, set screw 35 is then released to permit the
runner 32 to be extended to its maximum displacement within track assembly
31 so that the spacing between the cutting opening 24 and stage 33 is
substantially at a maximum. Rod 30 is then inserted into the hollow
interior of the plunger member 23 and the plunger is once again forcefully
urged through the housing member so as to project cutting end 27 out
through cutting opening 24. The core rod 30 is used to project excess
cartilage out from the exposed cutting end 27.
At its fullest insertion, rod 30 extends into hollow core 25 to fullest
insertion, rod 30 extends into hollow core 25 to within a predetermined
distance "x" of the cutting edge of end 27, so that the slug of cartilage
remaining after trimming has a length equal to "x".
This excess cartilage is trimmed by means of a scalpel 40 or the like, so
that all that remains is the portion of the cartilage plug retained within
the hollow interior 25 of the plunger 23. The trimming operation is
diagramatically illustrated in FIG. 7g. The retained plug is then ready
for attachment to a prosthetic device in a manner described herein below.
In order to eliminate the disadvantages and problems described above as
being associated with suturing the cartilage plug to the ossicular chain
prosthetic device, the flange of that device is modified in accordance
with the present invention so that the plug will attach directly to the
flange upon being urged against the flange. Since the modification of the
prosthetic device affects only the flange portion thereof, the
self-attachment feature of the present invention is applicable to both the
TORP and PORP types of prosthetic devices. The devices illustrated in
FIGS. 8a through 8i illustrate one general form of prosthetic devices
whereby the attachment of the cartilage plug to the flange is effected by
means of a member secured to the flange (or formed integrally therewith)
and arranged to penetrate and engage the cartilage plug when the plug is
urged against the flange. Referring specifically to FIG. 8a, an ossicular
replacement prosthetic device includes a stem or shaft portion 40 with a
flange 41. The projecting attachment member is configured as a barb 42
having a shaft connected to an extending perpendicularly from the flange
and terminating in a conical tip which is wider that the shaft at its
proximal end but tapers to a point at its distal end.
A modification of this structure may be found in FIG. 8b wherein the
projecting portion is a spike or needle 83 rather than a barb 42. Another
alternative embodiment is found in FIG. 8c wherein the barb 44 is shown as
being bifurcated longitudinally to facilitate engagement of the cartilage
plug. It should also be noted that the spike or needle of FIG. 8b may be
bifurcated in a similar manner. The attachment device of FIG. 8d takes the
form of a staple 45 embedded in the flange 41 and having its ends directed
perpendicularly away from the flange to receive the cartilage plug. In
FIG. 8e the projection takes the form of a tapered screw 46, in FIG. 8f it
takes the form of a modified spike or barb 47, in FIG. 8g it takes the
form of a hollow cylinder or shaft 48. FIG. 8h illustrates the projections
in the form of a plurality of needles extending from the flange 41. In
FIG. 8i a combination of different types of projections are illustrated
such as a barb 50 and a plurality of spikes 51. It should be noted that
any combination of elements which project into the plug may be employed in
a similar manner.
In the embodiments illustrated in FIGS. 8j through 8m, engagement of the
cartilage plug is by means of a partial enclosure of the plug at the
flange surface. For example, in FIG. 8j the flange 41 is illustrated as
including an annular wall disposed at its periphery and projecting
forwardly of the flange to receive the plug therein. Annular wall 52 may
be likened to a cuff or similar such structure. In FIG. 8k a modified cuff
is illustrated wherein the annular wall is segmented into equally
angularly spaced portions 53 which serve to receive and engage the
cartilage plug when it is forced against the flange 41. FIG. 81
illustrates an embodiment wherein the flange 41 is provided with a series
of angularly spaced prongs 54 disposed at its periphery and facing away
from the flange to, again, receive the cartilage plug when that plug is
forced against the flange. In FIG. 8m the engaging members constitute a
portion of staples or other resilient type members 55.
A third general category of means for attaching the cartilage plug
automatically to the prosthetic device in response to forceful engagement
between the plug and the prosthetic device is illustrated in FIGS. 8n and
8o. Specifically, the receiving surface of flange 41 is treated with an
adhesive material 56 which, upon contact with the cartilage plug, is
capable of being firmly secured to the cartilage plug. The adhesive
material 56 is preferably normally covered by a protective covering 57
which would normally be peeled from the adhesive material 56 prior to
attachment of the prosthetic device to the cartilage plug.
Of the various embodiments illustrated in Figures 8a through 8o, the
particular embodiments illustrated in FIGS. 8a through 8i, wherein the
cartilage plug is penetrated by a "male" projection, offers certain
advantages. More particularly, this type of attachment is purely
mechanical and, therefore, the risk of physiological reaction to an
adhesive is eliminated. In addition, this configuration permits reduction
of the diameter of the flange, as illustrated in FIGS. 9a and 9b, so that
the flange diameter is smaller than the diameter of the attached cartilage
plug. This feature further minimizes the possibility of any contact
between the prosthetic device and the tympanic membrane. Moreover, since
the only purpose of the flange is to provide stabilization of the
cartilage plug, the stabilization effected by the mechanical attachment
permits elimination of the flange entirely, as illustrated in FIG. 10a, or
at least a reduction in its diameter, as illustrated in FIG. 10b. For
these reasons a prosthetic device utilizing a "male" penetraing element
incorporated into the flange or exposed surface of the prosthetic device
constitutes the preferred form of the prosthetic device in accordance with
the present invention.
The procedure for attaching the cartilage plug to the prosthetic device of
the present invention using the cartilage punch of the present invention
is illustrated diagrammatically in FIGS. 11a through 11f. Specifically,
FIG. 11a illustrates the empty stage surface 34 of stage member 33 after
cartilage has been cut and retained by the cartilage punch. It is noted
that a recess 60 is provided in the stage surface 34. As illustrated in
FIGS. 11b and 11c recess 60 is configured to receive the prosthetic device
61 with the stem or shaft of the prosthetic device extending into the
recess and, if necessary, through the stage member 33, depending upon the
thickness of stage member 33. The surface of the prosthetic device to
which the cartilage plug is to be secured is positioned so as to face the
cutting opening 24 of the cartilage punch. With the prosthetic device 61
placed in recess 60, the runner 32 is retracted in slide member 31 so as
to place the retained prosthetic device 61 adjacent cutting opening 24. At
this time it is assumed that the plunger 23 is retracted within housing 21
so as not to interfere with the placing of the prosthetic device at the
cutting opening. This condition is illustrated in FIG. 11d. With the
prosthetic device properly positioned at the cutting opening, the plunger
is depressed, as illustrated in FIG. 11e, to force the retained cartilage
plug onto the prosthetic device 61 where it is automatically retained in
accordance with the present invention as described hereinabove. FIG. 11f
illustrates the finished prosthetic product, after it has been removed
from the cartilage punch, with the cartilage plug secured thereto.
It should be noted that the stage member 33 of the cartilage plug can be
adapted to be configured to receive any variety of prosthetic device
configurations. FIGS. 12a through 12e illustrate a variety of different
configurations for recess 60 so as to accommodate a corresponding variety
of different prosthetic device configurations. In each of FIGS. 12a
through 12e the recess 60 includes a bore extending entirely through the
stage member 33 so as to permit the entire shaft of the prosthetic device
61 to extend through and beyond the stage member. It should be noted that
the stage member may be provided with sufficient depth so that the stem or
shaft of the prosthetic device need not extend entirely therethrough,
whereby the recess 60 would not extend entirely through the stage member.
The entire procedure for cutting and retaining the cartilage plug in the
cartilage punch and then attaching the cartilage plug to the prosthetic
device takes no more than a few minutes and results in an attached
cartilage plug with a diameter appropriate for the prosthesis chosen for
implantation. The plug has no suture material between the perichondrium
and the tympanic membrane and has no sharp edges. These factors lessen the
change of extrusion or perforation. The process of the present invention
has the added advantage of taking only a negligable portion of the tragel
cartilage from the patient, thereby minimizing trauma to the patient.
The combination of the cartilage punch and ossicular replacement prosthesis
of the present invention, employed in the method of the present invention,
offers considerable advantages over the prior art surgical procedures for
obtaining a suitable prosthesis with a cartilage plug attached to the
flange. For example, the automatic cutting, retaining and applying of the
plug by the punch cuts down on the amount of work, skill and time required
to perform the procedure by hand. In addition, as noted above, no suture
material or other foreign substance is interposed between the
perichrondrium and tympanic membrane. Further, the resulting cartilage
plug corresponds to the dimensions of the flange of the prosthetic device
and has no sharp edges which could lead to perforation of the ear drum. It
should also be noted that the combination of the cartilage punch and the
modified prosthetic device allows a reduction in flange diameter to
further ensure against contact of the prosthetic device and the tympanic
membrane. Moreover, since in this process the flange only serves to
stabilize the cartilage plug, it may be possible to eliminate the flange
entirely. Finally, much less cartilage is removed from the tragus of the
patient, thereby lessening the trauma to the patient in obtaining the
necessary cartilage plug.
While I have described and illustrated specific embodiments of my
invention, it will be clear that variations of the details of construction
which are specifically illustrated and described may be resorted to
without departing from the true scope and spirit of the invention as
defined in the appended claims.
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