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Description  |
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BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a member and method for anchoring and
relieving the strain on a percutaneous lead and, more particularly, to a
member and method for anchoring and relieving the strain on a flexible,
conductive percutaneous lead where the lead exits the body of a patient.
Various flexible, percutaneous leads, have been employed in the past which
extend into the body of a patient and exit the patient's body at some
selected location on the body. Such leads, for example, may include
electrically conductive temporary or permanent heart pacer leads or neural
stimulator leads for stimulating the nervous system of the patient. One
end of such lead, the end in the patient's body, is located at the
location which is to be stimulated, for example the myocardium or in the
epidural space surrounding the spinal cord. The conductive lead exits the
body at a conveniently selected location and the other end of the lead is
connected to a stimulator which may be carried on the exterior of the
patient's body. The stimulator produces electrical signals which are
transmitted through the lead to stimulate the tissue which is to be
stimulated deep within the patient's body.
In the past, such percutaneous leads have been fixed in place at the
location at which the lead exits the body by sutures in the skin at that
location. Such suturing method of fixation has several disadvantages. One
disadvantage is that strains which may be imparted to the lead during
patient activity are transmitted to the sutured exit location and may
cause movement or displacement of the lead and tearing of the skin by the
sutures with attendant trauma to the patient. Another disadvantage is that
the sutured exit is subject to infection, not only due to exposure of the
sutures and lead(s) themselves, but also as a result of displacement of
the lead due to strains which may be imparted to the lead and the sutures
at the lead exit location during patient activity. Another disadvantage is
the need for the sutures themselves, which are subject to infection, which
may produce trauma, and which may result in puncturing of the insulation
on the lead during placement of or strain on the sutures.
A member and method for anchoring and relieving the strain on such leads
incorporating the principles of the present invention substantially
reduces the likelihood of the occurrence of these disadvantageous
consequences. A member and method incorporating the principles of the
present invention firmly anchors and stabilizes the lead against movement
at its exit location from the body during activity of the patient, thus
substantially reducing the possibility of displacement of the lead or of
infection or trauma resulting from such displacement and movement. The
member and method incorporating the principles of the present invention
also covers the lead exit to protect the exit against contamination which
could lead to infection. The member and method incorporating the
principles of the present invention is both simple to use, install and
remove, and is inexpensive. The member and method incorporating the
principles of the present invention firmly anchors the lead and may, in
many cases, reduce, if not eliminate the need altogether for sutures for
closure of the exit and the attendant disadvantages of such sutures.
In one principal aspect of the present invention, a member for anchoring
and relieving the strain on a flexible, percutaneous lead which exits the
body of a patient comprises a flexible disc having a first surface for
contacting and conforming to the body of the patient at the location at
which the lead exits the body, and a second surface opposite the first
surface. An adhesive is located on the first surface for adhering the disc
and its first surface to the body at the location at which the lead exits
the body and over substantially the entire area of the first surface. A
passage of substantially constant cross-section over its length extends
through the thickness of the disc and opens through the first and second
surfaces, the substantially constant cross-section being sized to snugly
receive a lead which is also of substantially constant cross-section and
such that the constant cross-section of the lead may be slidably
positioned in the passage to extend beyond the first and second surfaces.
In another principal aspect of the present invention, the aforesaid member
includes a bulbous shaped head projecting from the second surface of the
disc and the passage extends into and opens through this head.
In still another principal aspect of the present invention, the
aforementioned members may also include a slit through the disc extending
from the perimeter of the disc to the passage, whereby the disc may be
opened to be positioned around the head.
In still another principal aspect of the present invention, a method of
anchoring and relieving the strain on a flexible, percutaneous lead which
exits the body of a patient comprises positioning one end of the lead
through the skin of the patient, positioning the portion of the lead which
exits the patient's body to extend snugly through a passage through the
thickness of a flexible disc such that the lead extends from both sides of
the disc, shaping a surface of the disc to conform to the patient's body
and positioning the surface against the body at the location where the
lead exits the patient's body, and adhesively bonding the surface to the
patient's body at the last mentioned location to anchor the disc and lead
thereto.
In still another principal aspect of the present invention, the
aforementioned method includes the disc having a bulbous shaped head
projecting from a surface of the disc opposite the last mentioned surface,
with the passage also extending into and opening through the head. The
lead is positioned to extend through the passage in the head and is
secured in the passage by binding a flexible thread means around the stem
portion of the bulbous shaped head.
In still another principal aspect of the present invention, the
aforementioned methods also include the disc having a slit extending from
the perimeter of the disc to the passage, and the lead is positioned in
the passage by opening the disc at the slit and sliding the lead through
the open slit to the passage.
These and other objects, features and advantages of the present invention
will be clearly understood through a consideration of the following
detailed description.
BRIEF DESCRIPTION OF THE DRAWING
In the course of this description, reference will frequently be made to the
attached drawing in which:
FIG. 1 is an overall perspective view of a member incorporating the
principles of the present invention and for practicing the method of the
present invention and in which the member is anchored to the body of a
patient at the location at which the lead exits the body of the patient;
FIG. 2 is a cross-sectioned elevational view of the member shown in FIG. 1;
FIG. 3 is a plan view showing an alternative embodiment of member
incorporating the principles of the present invention; and
FIG. 4 is an overall perspective view of the altnerative embodiment shown
in FIG. 3 in the process of being installed about the lead.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIGS. 1 and 2 one preferred embodiment of member for anchoring and
relieving the strain on a flexbile, percutaneous lead at the location at
which the lead exits the body of a patient is shown. The lead L may be one
or more insulated conductors which are connected to a suitable stimulator
(not shown). Where the lead is a heart pacer lead, the distal end of the
lead which is to be positioned in the patient's heart may be terminated by
a curved needle fastened to the conductor. The exterior, proximal end of
the lead may be fastened to a straight needle N and, once the lead is
ready for connection to the stimulator, the tip N' of the needle may be
broken or cut off to leave a pin N" remaining which acts as a terminal as
shown in FIG. 1. The stimulator generates selected electrical pulses or
signals for stimulating certain locations inside the patient's body B and
these pulses or signals are conducted through the lead L to those
locations. By way of example, the end of the percutaneous lead in the
patient's body B and its curved needle may be located in the patient's
myocardium, in the case of a heart pacer, or the end of the lead may be
located in the epidural space surrounding the patient's spinal cord, in
the case of a neural stimulator.
The member preferably comprises a flexible disc 10 having a bottom surface
12, as shown in FIG. 2, which is capable of being flexed to contact and
conform to the shape of the patient's body B at the location at which the
lead L is to exit the body. The disc 10 could also be preshaped to conform
to body contours. This surface 12 is coated over substantially its entire
surface area with an adhesive layer 14 for adhering the surface 12 to the
patient's body B at the lead exit location, as shown in FIGS. 1 and 2.
Although it may not always be necessary, a backing 16, as shown in FIG. 2,
is preferably included covering the adhesive 14 and protecting it against
contamination prior to use and maintains the adhesive and surface 12 in a
sterile condition. The backing 16 may be formed of a coated paper or a
polymeric sheet material and is preferably peelable in a manner known to
those skilled in the art so that it may be peeled from the adhesive layer
14 when the member is being readied for use. An antibiotic or other
sterilizing substance may also be incorporated into the adhesive to help
prevent sepsis.
The surface 18 of the disc 10, on the side of the disc opposite the surface
12, preferably includes a bulbous shaped head 20 substantially centered on
the disc. The head 20 includes a narrower stem portion 22 and an upper
wider portion 24. A substantially vertical passage 26 extends through the
thickness of the disc 10 and, at its bottom end, opens through the surface
12 and its adhesive layer 14. The top of passage 26 opens through the top
of the wider portion 24 of the head 20, as shown in FIG. 2, and is
preferably flared at 28 at its point of exit from the head 20, as is also
shown in FIG. 2. With the exception of the flare 28, the passage 26 is of
substantially constant cross-section over its length. The cross-sectional
shape of the passage is substantially identical to the cross-sectional
shape of the lead L and the diameter of the passage 26 is sized so that it
snugly fits the lead L when the lead is inserted through the passage as
shown in FIG. 1.
Installation is accomplished by inserting the end of the lead L into the
patient's body and positioning its end at the location to be stimulated,
e.g. the heart, spinal cord, etc. By way of example, where the lead is a
heart pacer lead, the end of the lead in the body typically terminates in
a curved needle (not shown) which is inserted into the patient's
myocardium. Once the lead has been positioned, the other end of the lead
outside of the body is inserted upwardly through the passage 26 via needle
N and the disc 10 is slid downwardly along the lead until it contacts the
skin of the patient and conforms to the curvature of the patient's skin
surface at the exit location. At this point, the disc 10 and its surface
12 are adhered to the body at the lead exit location with the adhesive
layer 14 to anchor the disc 10 and the lead L firmly to the body. The lead
L, which is also of substantially constant cross-section over its length,
fits snugly in the passage 26.
The lead is preferably further secured by tying or binding with a suitable
thread-like member, such as a suture 30, about the stem portion 22 of the
bulbous shaped head 20, as shown in FIG. 1. Tying with the suture 30 not
only seals the passage 26 against the entry of contaminants to protect
against infection, but also firmly secures the lead L in the passage 26
against sliding or other displacement. Although a suture 30 is shown about
the stem portion 22, it will be understood that other forms of fixation
may be employed, such as a clamp, clip, applied adhesive, elastic band,
etc. At this time, the tip N' of the needle N may be broken or cut off and
the remaining portion N" of the needle may be coupled to a suitable
stimulator (not shown).
A second alternative preferred embodiment of member is shown in FIGS. 3 and
4. The member in this embodiment is substantially identical to the member
previously described and, thereby, the same reference numerals will be
utilized to identify components which are substantially identical to each
other in both of the embodiments.
The principal difference between the embodiments shown in FIGS. 3 and 4 and
that shown in FIGS. 1 and 2 is that the embodiment in FIGS. 3 and 4
includes a slit 32 which extends through the thickness of the disc 10 and
between the perimeter 34 of the disc and the passage 26 into and through
the head 20. The slit 32 enables the disc 10 to be pulled apart to create
a radially extending opening 36, as shown in FIG. 4, to allow the member
to be assembled around or removed from the lead L after the lead has been
fully inserted and positioned at its desired location in the body B of the
patient and without the need to slide the exterior end of the lead through
passage 26. This embodiment is particularly advantageous where the
diameter of the terminal N" may be larger than the diameter of the lead L.
Once the disc 10 has been positioned about the lead L at its exit from the
body B of the patient and the lead has been positioned in the passage 26,
the disc 10 and its surface 12 may be slid down the lead L, to the extent
necessary, is flexed to conform to the surface of the body of the patient,
and the disc is adhesively adhered to the body at the location of the exit
of the lead from the body. The thread or suture 30 is then tied about the
stem portion 22 of the bulbous shaped head 20 to secure the opening 36
produced by the slit 32 in its closed position and to snugly secure the
lead L in the passage 26 to prevent the entry of contaminants through the
passage and anchor the lead against movement.
The preferred embodiments of the invention which have been described are
preferably formed by integrally molding the disc 10 and its bulbous shaped
head 20 of a substantially flexible material of, for example, an
elastomeric polymer, such as Silastic. The anchoring and strain relieving
members are preferably quite flexible to allow conformation with the shape
of the body of the patient at the location of exit of the lead and may be,
for example, on the order of 55 Durometer in hardness.
It will be understood that although the disc 10 is shown as being
substantially circular in shape, the shape of the disc may vary as desired
and as may be preferable for certain applications. For example, the disc
10 may be square, rectangular, oval, or figure eight, in shape.
Although the lead L has been described as being a single electrical
conductor, it is not intended that the present invention be limited only
to use with such electrical conductors. It will be apparent that the
principles of the invention may be practiced to anchor and relieve the
strain of any elongate, flexible component with or without conductors or
with more than one conductor, and which component is intended to enter the
patient's body through the skin. For example, the lead L may comprise a
catheter for fluids. Thus, the term "lead" as employed herein is intended
to include any flexible percutaneous component, such as insulated or
non-insulated electrical conductors, intravascular cardiac catheters,
infusion, drainage or irrigation tubes for body cavities, ducts or cysts
and abscesses, and pneumatic tubes for powering cardiac assist devices,
artificial hearts, etc.
It will also be seen that the principles of the invention may be practiced
where more than a single lead as shown is employed. Where multiple leads
are employed, the bulbous shaped head 20 may include more than one passage
26 or may include plural heads 20 each with a single passage.
From the foregoing, it will be seen that the member and method described
herein result in several advantages not present in the prior suturing
methods of lead attachment. One such advantage is the reduction in the
possibility of infection and trauma due not only to the seal which is
effected by the member of the present invention at the location of exit of
the lead from the patient's body after the member is installed, but also
due to the anchoring and strain relief of the lead after installation and
during activity of the patient. Strain forces which may be imparted to the
lead L during activity of the patient tend to be dissipated not only by
flexing of the bulbous shaped head 20, as shown by the dot and dash lines
in FIG. 1, but these forces are also distributed over the area of the disc
10. The anchoring action of the present invention substantially minimizes,
if not eliminates, the need for suturing of the lead at the exit location,
thus reducing the possibility of patient infection and trauma or damage to
the lead insulation. The present invention is capable of being quickly,
easily and inexpensively fixed on the body of the patient and
substantially reduces the possibility that the lead L might be moved or
displaced after placement in the patient.
It will be understood that the embodiments of the present invention which
have been described are merely illustrative of a few of the applications
of the principles of the present invention. Numerous modifications may be
made by those skilled in the art without departing from the true spirit
and scope of the invention.
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