U.S. patent application number 13/285074 was filed with the patent office on 2012-02-23 for method for making smooth transitions between differing lead segments.
This patent application is currently assigned to Medtronics, Inc.. Invention is credited to Daniel J. Stetson, Brian T. Stolz, Carole A. Tronnes.
Application Number | 20120042517 13/285074 |
Document ID | / |
Family ID | 42629620 |
Filed Date | 2012-02-23 |
United States Patent
Application |
20120042517 |
Kind Code |
A1 |
Tronnes; Carole A. ; et
al. |
February 23, 2012 |
METHOD FOR MAKING SMOOTH TRANSITIONS BETWEEN DIFFERING LEAD
SEGMENTS
Abstract
A method for forming a lead body includes contacting a proximal
section of the lead body having a lumen and a first lead body
characteristic to a distal section of the lead body having a lumen
and a second lead body characteristic. The proximal and distal
sections are contacted such that their lumens are axially aligned.
A lap band is disposed about a portion of the proximal section and
a portion of the distal section, and is thermally formed to the
proximal and distal sections. Axially compressive pressure is
applied to the lap band as the lead body is being thermally formed.
The pressure applied is sufficient to result in the lead body
having an outer diameter in regions proximally and distally
adjacent to the lap band that are substantially the same to an
outer diameter in a region formed by the lap band.
Inventors: |
Tronnes; Carole A.;
(Stillwater, MN) ; Stetson; Daniel J.; (Lino
Lakes, MN) ; Stolz; Brian T.; (Bloomington,
MN) |
Assignee: |
Medtronics, Inc.
Minneapolis
MN
|
Family ID: |
42629620 |
Appl. No.: |
13/285074 |
Filed: |
October 31, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12707116 |
Feb 17, 2010 |
8061026 |
|
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13285074 |
|
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61154461 |
Feb 23, 2009 |
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Current U.S.
Class: |
29/874 |
Current CPC
Class: |
H01R 4/00 20130101; Y10T
29/49174 20150115; Y10T 29/49117 20150115; Y10T 29/49204 20150115;
Y10T 29/49199 20150115; Y10T 29/49176 20150115; H01R 2201/12
20130101; Y10T 156/1066 20150115; A61N 1/05 20130101 |
Class at
Publication: |
29/874 |
International
Class: |
H01R 43/16 20060101
H01R043/16 |
Claims
1. A method for forming a lead body having a transition from a
first section to a second section, the method comprising:
contacting (i) a proximal portion of the second section of the lead
body to (ii) a distal portion of the first section of the lead
body, wherein the proximal portion of the second section of the
lead body defines a lumen, wherein the distal portion of the first
section of the lead body defines a lumen, and wherein the proximal
portion of the second section is contacted with the distal portion
of the first section such that the lumen of the proximal portion of
the second section is axially aligned with the lumen of the distal
portion of the first section; disposing a lap band about at least a
portion of the proximal portion of the second section and at least
a portion of the distal portion of the first section; thermally
forming the lead body by bonding the lap band to the proximal
portion of the second section and the distal portion of the first
section; and applying axially compressive pressure to the lap band
as the lead body is being thermally formed, wherein the pressure
applied is sufficient to result in the lead body having an outer
diameter in regions proximally and distally adjacent to the lap
band that are substantially the same to an outer diameter in a
region formed by the lap band.
2. The method of claim 1, wherein contacting the proximal portion
of the second section to the distal portion of the first section
such that the lumen of the proximal portion of the second section
is axially aligned with the lumen of the distal portion of the
first section comprises disposing the proximal portion of the
second section and the distal portion of the first section about a
mandrel, wherein the mandrel axially aligns the lumen of the
proximal portion of the second section and the lumen of the distal
portion of the first section.
3. The method of claim 2, wherein the mandrel has an outer
diametric dimension substantially the same as the inner diametric
dimension of the lumens of the proximal portion of the first
section and distal portion of the second section.
4. The method of claim 1, wherein the second section of the lead
body has a substantially uniform inner diameter, and has a first
outer diameter along a length from a proximal end to a location
distal to the proximal end, and has a second outer diameter distal
to the location distal to the proximal end, wherein the first outer
diameter is smaller than the second outer diameter.
5. The method of claim 4, wherein contacting the proximal portion
of the second section to the distal portion of the first section
such that the lumen of the proximal portion of the second section
is axially aligned with the lumen of the distal portion of the
first section comprises disposing at least a portion of the distal
portion of the first section about at least a portion of the
proximal portion of the second section having the first outer
diameter.
6. The method of claim 4, wherein the proximal portion of the
second section of the lead body has a thickness and wherein half
the difference in the second outer diameter and the first outer
diameter of the second section of the lead body is substantially
the same as the thickness of the distal portion of the first
section.
7. The method of claim 1, wherein the first section of the lead
body has a substantially uniform inner diameter, has a first outer
diameter along a length from a distal end to a location proximal
the distal end, and has a second outer diameter proximal to the
location proximal the distal end, wherein the first outer diameter
is smaller than the second outer diameter.
8. The method of claim 7, wherein contacting the proximal portion
of the second section to the distal portion of the first section
such that the lumen of the proximal portion of the second section
is axially aligned with the lumen of the distal portion of the
first section comprises disposing at least a proximal portion of
the second section about at least a portion of the first section
having the first outer diameter.
9. The method of claim 8, wherein the distal portion of the second
section of the lead body has a thickness and wherein the thickness
of the proximal portion of the second section is about half the
difference of the second outer diameter and the first outer
diameter of the first section.
10. A method for forming a lead body, the method comprising:
providing a distal section of the lead body having a substantially
uniform inner diameter, a first outer diameter along a first length
from a proximal end to a first location distal the proximal end,
and a second outer diameter distal the first length, wherein the
first outer diameter is smaller than the second outer diameter,
wherein a lumen extends through the distal section of the lead body
from the proximal end of the distal section to a distal end of the
distal section; providing a proximal section of the lead body
having a substantially uniform inner diameter, a first outer
diameter along a first length from a distal end to a first location
proximal the distal end, and a second outer diameter proximal the
location proximal the distal end, wherein the first outer diameter
is smaller than the second outer diameter, wherein a lumen extends
through the proximal section of the lead body from the distal end
of the proximal section to a proximal end of the proximal section;
contacting the proximal section to the distal section such that the
lumen of the proximal section is axially aligned with the lumen of
the distal section; disposing a lap band about a portion of the
proximal section and a portion of the distal section; bonding the
lap band to the proximal and distal sections.
11. The method of claim 10, wherein contacting the proximal section
to the distal section comprises contacting the distal end of the
proximal section to the proximal end of the distal section.
12. The method of claim 11, wherein the lap band has a thickness,
wherein the first outer diameter of the proximal section is
substantially the same as the first outer diameter of the distal
section, wherein the second outer diameter of the proximal section
is substantially the same as the second outer diameter of the
distal section, wherein the thickness of the lap band is about half
the difference of the second outer diameter of the proximal section
and the first outer diameter of the proximal section, and wherein
forming the lead body comprises forming a lead body having a
substantially uniform outer diameter from a location proximal the
lap band region to a location distal the lap band region.
13. The method of claim 10, wherein the distal section of the lead
includes a second length from the first location to a second
location distal the first location, wherein the outer diameter of
the second length is the second outer diameter of the distal
section and wherein the distal section has a third outer diameter
distal the second location, wherein the third outer diameter is
greater than the second outer diameter.
14. The method of claim 13, wherein contacting the proximal section
to distal section comprises disposing at least a distal portion of
the proximal section about at least a portion of the first length
of the distal section.
15. The method of claim 14, wherein the inner diameter of the
proximal section is substantially the same as the outer diameter of
the distal section along the first length, wherein the first outer
diameter of the proximal section is substantially the same as the
second outer diameter of the distal section, wherein the second
outer diameter of the proximal section is substantially the same as
the third outer diameter of the distal section, wherein the lap
band has a thickness that is about half the difference between the
second outer diameter of the proximal section and the first outer
diameter of the proximal section, and wherein disposing the lap
band about a portion of the proximal section and a portion of the
distal section comprises disposing the lap band about the first
length of the proximal section and the second length of the distal
section.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/707,116, filed Feb. 17, 2010, now allowed,
which claims the benefit of priority to U.S. Provisional Patent
Application No. 61/154,461, filed on Feb. 23, 2009, which
applications are hereby incorporated herein by reference in their
entirety to the extent that they do not conflict with the
disclosure presented herein.
FIELD
[0002] This application relates to medical devices, more
particularly implantable medical leads and to methods for
manufacturing leads.
BACKGROUND
[0003] Electrical stimulation technology is expanding in scope,
resulting in therapies that place leads in more and more areas of
the body and in leads that have increasing levels of complexity.
The stiffness of a lead body can be important for its function in
many ways. For example, a very flexible lead body may be desirable
for implantation in tissues that experience a lot of movement. A
stiffer lead body may be important for guiding through tissue or
for insertion into a device, such as an electrical signal
generator. For example, if the portion of a lead to be inserted
into a device is not sufficiently stiff, pushing the lead into a
receptacle of the device may be difficult.
[0004] In transitioning from a stiff to a more flexible segment
along the length of a lead, it is desirable for the transition to
be smooth to spread any stresses out evenly over the length of the
transition. Many ways of transitioning between segments of
differing lead flexibilities have been devised. However, some are
impractical from a manufacturing perspective or result in undesired
characteristics. For example, lap bonding of two sections of
differing stiffnesses can result in a reliable bond that spreads
stresses out over the length of the lap bonded section; however,
such lap bonding also results in increased thickness of the lead
body. Such leads have a bulge in their outer diameter, which may be
undesirable.
BRIEF SUMMARY
[0005] Leads having smooth transitions between differing segments
and having uniform outer diameters along and in proximity to the
transition section are described herein. Practical methods for
manufacturing such leads are also described herein.
[0006] In various embodiments, a method for forming a lead body
having a transition from a section having a first lead body
characteristic to a section having a second lead body
characteristic, as described herein, includes contacting a proximal
section of the lead body having the first lead body characteristic
to a distal section of the lead body having the second lead body
characteristic. The proximal and distal sections of the lead body
define lumens. The proximal and distal sections are contacted such
that the lumen of the proximal section is axially aligned with the
lumen of the distal section. The method further comprises disposing
a lap band about a portion of the proximal section and a portion of
the distal section, and thermally forming the lead body by bonding
the lap band to the proximal and distal sections. Axially
compressive pressure is applied to the lap band as the lead body is
being thermally formed. The pressure applied is sufficient to
result in the lead body having an outer diameter in regions
proximally and distally adjacent to the lap band that are
substantially the same as an outer diameter in a region formed by
the lap band.
[0007] In various embodiments, a method for forming a lead body
having a transition from a section having a first lead body
characteristic to a section having a second lead body
characteristic, as described herein, includes contacting a proximal
section of the lead body to a distal section of the lead body. The
distal section of the lead body defines a lumen extending through
the distal section, has a substantially uniform inner diameter, has
a first outer diameter along a first length from a proximal end of
the first precursor to a first location distal the proximal end,
and has a second outer diameter distal the first location. The
first outer diameter is smaller than the second outer diameter. The
proximal section of the lead body defines a lumen extending through
the proximal section, has a substantially uniform inner diameter,
has a first outer diameter along a first length from a distal end
of the second precursor to a first location proximal the distal end
to form the proximal section of the lead body, and has a second
outer diameter proximal the location proximal the distal end. The
first outer diameter is smaller than the second outer diameter. The
proximal and distal sections are contacted such that the lumen of
the proximal section is axially aligned with the lumen of the
distal section. A lap band is disposed about a portion of the
proximal section and a portion of the distal section and is
thermally bonded to the proximal and distal sections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIGS. 1-2 are schematic drawings of side views of
representative leads.
[0009] FIG. 3 is a schematic drawing of a side view of a
representative system including an electrical signal generator and
a lead.
[0010] FIGS. 4A-B are schematic drawings of side views (4A,
exploded) of a representative lead and introducer.
[0011] FIG. 4C is a schematic drawing of a cross section through
the lead and introducer shown in FIG. 4B taken through line
4C-4C.
[0012] FIG. 5 is a schematic drawing of a representative lead
illustrating a method for making the lead.
[0013] FIGS. 6A-B are schematic drawings of a representative lead
illustrating a method for making the lead.
[0014] FIGS. 7A-B are schematic drawings of a representative lead
illustrating a method for making the lead.
[0015] FIGS. 8A-C are schematic drawings of a representative lead
illustrating a method for making the lead.
[0016] FIGS. 9A-C are schematic drawings illustrating a method for
making a distal section of a lead as shown in FIG. 8A.
[0017] FIGS. 10A-B are schematic drawings illustrating a method for
making a proximal section of a lead as shown in FIG. 8A.
[0018] The drawings are not necessarily to scale. Like numbers used
in the figures refer to like components, steps and the like.
However, it will be understood that the use of a number to refer to
a component in a given figure is not intended to limit the
component in another figure labeled with the same number. In
addition, the use of different numbers to refer to components is
not intended to indicate that the different numbered components
cannot be the same or similar.
DETAILED DESCRIPTION
[0019] In the following detailed description, reference is made to
the accompanying drawings that form a part hereof, and in which are
shown by way of illustration several specific embodiments of
devices, systems and methods. It is to be understood that other
embodiments are contemplated and may be made without departing from
the scope of spirit of the present invention. The following
detailed description, therefore, is not to be taken in a limiting
sense.
[0020] All scientific and technical terms used herein have meanings
commonly used in the art unless otherwise specified. The
definitions provided herein are to facilitate understanding of
certain terms used frequently herein and are not meant to limit the
scope of the present disclosure.
[0021] As used herein "substantially" means to a great extent or
degree. Thus, two items or characteristics that are substantially
the same are the same to a great extent or degree. For example, the
two items or characteristics may be the same to the extent that
processes for producing the things or characteristics are
reproducible. Alternatively, or in addition, two things or
characteristics that are substantially the same may be generally
indistinguishable when considered for their intended purpose or
purposes. For example, if two sections of a lead are to have
substantially the same outer diameter so that the lead may be
slidably disposed in an introducer with tight tolerances, then if
the both sections slide through the introducer without difficulty
the two outer diameters can be considered substantially the
same.
[0022] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" encompass embodiments having
plural referents, unless the content clearly dictates otherwise. As
used in this specification and the appended claims, the term "or"
is generally employed in its sense including "and/or" unless the
content clearly dictates otherwise.
[0023] The present disclosure relates to medical leads, such as
leads and lead extensions, having smooth transitions between
segments having differing characteristics. The leads have uniform
diameters along and in proximity to the transition section.
[0024] Leads as described herein may be used in conjunction with
any suitable electrical medical device, such as an electrical
signal generator system or a monitoring system. Examples of
electrical signal generator systems that such leads may be used
with include spinal cord stimulators, gastric stimulators, sacral
nerve stimulators, deep brain stimulators, cochlear implants,
defibrillators, pacemakers, and the like. In many embodiments, such
electrical medical devices are implantable.
[0025] Any suitable type of lead may be adapted according to the
teaching presented herein. By way of example and with reference to
FIG. 1 and FIG. 2, examples of representative leads 20 are shown.
Leads 20, as shown in FIGS. 1 and 2, contain four exposed
electrical contacts 80 and four electrodes 90. However, leads 20
may contain any suitable number of electrodes 90 or contacts 80.
The contacts 80 are disposed in proximity to the proximal end 40 of
the lead 20. The electrodes 90 are disposed in proximity to the
distal end 50 of the lead 20. Conductive wires (not shown)
electrically couple discrete contacts 80 with discrete electrodes
90. The conductors run within the lead body 30. The contacts 80 are
configured to couple electrical contacts of an electrical signal
generator, such that signals generated by the active device may be
applied to a tissue of a patient in which the distal end 50 of the
lead 20 is implanted. A signal generated by the device is
transmitted via a contact 80 along a conductor to an electrode 90
and to tissue in which the electrode 90 is implanted. The lead 20
shown in FIG. 1 is of a type generally referred to as a
percutaneous lead. The lead 20 shown in FIG. 2 is a paddle-type, or
surgical, lead. However, it will be understood that any lead
configuration may be employed in accordance with the teachings
provided herein.
[0026] Still with reference to FIGS. 1-2, at some point along the
length of the lead body 30 there is a transition region 60 where
the lead body 30 transitions from a section 70 having a first
characteristic to a section having a second characteristic 75. The
transition may be between any two characteristics. For example the
transition may be between a region having more rigidity to a region
having more flexibility, between a region having one color and a
region having another color, or the like. The transition region 60
may be located at any suitable position along the length of the
lead body 30.
[0027] In various embodiments, the lead body transitions at a
transition region 60 from a first rigid section 70 to a second more
flexible section 75. The rigid section 75 includes the proximal end
40 of the lead body 30 and is sufficiently stiff to allow easy and
reliable insertion into a receptacle of an active electrical
medical device. For example, in some embodiments, the rigid section
75 has a flexural modulus of about 0.003 lbf-in.sup.2 or
greater.
[0028] For example and with reference to FIG. 3, the rigid proximal
section 70 of the depicted lead body 30 is configured to be
inserted into a receptacle 110 of a header 120 of an implantable
electrical signal generator 10. The receptacle 110 includes
internal electrical contacts (not shown) configured to contact an
electrically couple with contacts 80 of the lead. Hermetically
sealed feedthroughs not shown) electrically couple the internal
contacts to electronics in the primary hermetically sealed housing
of the signal generator 10. The proximal portion 70 of the lead
body 30 is sufficiently rigid to allow for reproducible and ready
insertion into, or withdrawal from, the receptacle 110 to provide
reliable electrical coupling between contacts 80 of the lead and
the receptacle 110 of the active electrical device 10. While not
shown, it will be understood that leads configured to be coupled to
lead extensions or other devices having receptacles configured to
receive the lead may also benefit from having a rigid proximal
section.
[0029] In the embodiments depicted in FIGS. 1-3, the transition
section 60 through which the lead body 30 transitions from a
section 70 having a first characteristic, e.g. rigidity, to a
section 75 having a second characteristic, e.g. flexibility, has a
substantially uniform outer diameter in the transition section 60
and proximal and distal to the transition section 60. In addition
to aesthetic purposes, the substantially uniform outer diameter may
serve a variety of functional purposes. For example and with
reference to FIGS. 4A-C, a lead 20 having a substantially uniform
outer diameter may be beneficial when the lead 30 is introduced
into a patient through an introducer 200, such as a Touhy needle.
The depicted introducer 200 has a proximal end 210, a distal end
220 and a lumen 230 extending through the introducer 200 from the
proximal end 210 to the distal end 220. The lumen 230 is configured
to slidably receive the lead 20. The clearance between the outer
diameter of the lead body 30 and the inner diameter of the
introducer 200 is desirably kept small so that use of excessively
small gauge introducer needles, which may cause trauma to the
patient, is avoided. Due to the typically small clearance between
the lead body 30 and the inner surface of the introducer 200
defining the lumen 230, it is desirable to minimize differences in
the outer diameter in the transition region 60 and those regions
proximal and distal to the transition region 60 so that lead 20 may
be readily inserted into, or withdrawn from, the introducer
200.
[0030] Leads that have a smooth transition between a section having
a first characteristic and a section having a second characteristic
and which have a substantially uniform diameter throughout the
transition section and proximal and distal to the transition
section are described below. Methods for making such leads are also
described in more detail below. Referring now to FIGS. 5-9, various
representative longitudinal sections of lead bodies and methods are
shown. For the purposes of clarity only polymeric tubes or portions
thereof that are used to form the lead body are shown. It will be
understood that leads may include other components such as a
shield, conductive wires, contacts, electrodes, reinforcement
members such as a mesh, and the like. In the embodiments depicted,
a proximal section 310 of the lead body is shown as being the
section having the first characteristic 70 and a distal section of
the lead body 320 is shown as being the section having the second
characteristic 75. Of course, it will be understood that the distal
section may have the first characteristic and the proximal section
may have the second characteristic.
[0031] In the embodiment depicted in FIG. 5, the proximal section
310 of the lead body is contacted with the distal section 320 of
the lead body and the lumen 330 of the proximal section 310 is
axially aligned with the lumen 340 of the distal section 320. The
distal end of the proximal section 310 is in contact with the
proximal end of the distal section 320. The inner diameters of the
distal and proximal sections of the lead body are substantially the
same. The proximal lead body section 310 has a first outer diameter
from the distal end to a location 350 proximal the distal end and
has a second outer diameter proximal to the location 350. The
second outer diameter is greater than the first outer diameter. The
distal lead body section 320 has a first outer diameter from the
proximal end to a location 360 distal the proximal end and has a
second outer diameter distal to the location 360. The second outer
diameter is greater than the first outer diameter. The first outer
diameter of the proximal section 310 is substantially the same as
the first outer diameter of the distal section 320. A lap band 300
has a thickness that is about half the difference between the
second outer diameter and the first outer diameter of either the
proximal 310 or distal 320 sections. The lap band 300 has a length
that is substantially the same as the cumulative length of: the
distance from the distal end of the proximal section 310 to the
location 350 proximal the distal end; and the distance from the
proximal end of the distal section 320 to the location 360 distal
the proximal end. Thus, the lap band 300 is configured to abut the
shoulder formed at the location 350 where the proximal section 310
transitions from the first outer diameter to the second outer
diameter and is configured to abut the shoulder at the location 360
where the distal section 320 transitions from the first outer
diameter to the second outer diameter, when the distal end of the
proximal section 310 and the proximal end of the distal section 320
are in contact. The area of the lead body formed by the lap band
300 is the transition section 60 of the lead body, and the outer
diameter of the lead body is substantially uniform along the
transition region 60 and proximal and distal to the transition
section 60.
[0032] The lead body may be formed by thermally bonding the lap
band 300 to the proximal section 310 and the distal section 320. In
various embodiments, such lap bonding occurs when the lap band
material is heated to 100.degree. C. or higher depending on the
material. The lap band 300, proximal section 310 and distal section
320 may be made of any suitable thermoplastic polymer. Examples of
suitable thermoplastic polymers include polyurethane, polysulfone,
polyethylene, and polypropylene. In various embodiments, the lap
band 300, the proximal section 310, and the distal section 320 are
made of the same type of polymeric material. In the case of
polyurethane, lap bonding may occur at about 250.degree. C. to
about 300.degree. C.
[0033] When each of the lap band 300, the proximal section 310, and
the distal section 320 are made of the same type of polymeric
material and the proximal section is more rigid than the distal
section, similar materials of different durometers may be used.
[0034] Referring now to FIGS. 6A-B, a proximal section 310 of a
precursor to a lead body is contacted with a distal section 320 of
a lead body such that the lumen 330 of the proximal section 310 is
axially aligned with the lumen 330 of the distal section 320. The
distal end of the proximal section 310 is in contact with the
proximal end of the distal section 320. A lap band 300 is disposed
about the proximal 310 and distal 320 sections. The lead body (see
FIG. 6B) is thermally formed by bonding the lap band 300 to the
proximal 310 and distal 320 sections. An axially compressive force
is applied to the lap band 300 as the lead body is being thermally
formed. Sufficient axial pressure is applied to result in the lead
body having an outer diameter in regions proximal and distal the
transition section 60 formed by the lap band that are substantially
the same as the outer diameter in the region 60 formed by the lap
band 300.
[0035] To prevent collapse of the lumen 370 as the lead body is
being formed and to provide sufficient normal force to the axially
compressive force applied to the lap band 300 to form the uniform
transition section 60, the proximal 310 and distal 320 sections may
be placed about a mandrel (not shown) having an outer diameter
substantially the same as the inner diameter of the sections 310,
320. To achieve sufficient axially compressive force to result in a
substantially uniform outer diameter of the lead body in the
transition section 60, a die (not shown) may be used to provide the
axial pressure. It will be understood that the amount of axial
pressure applied necessary to achieve a substantially uniform outer
diameter will vary from material to material and process conditions
to process conditions. For purposes of example, when employing
distal 320 and proximal 310 polyurethane sections having an 0.050
inch OD.times.0.030 inch ID and durometers of 55D and 75D and a
polyurethane lap band 300 having a 55D durometer and an 0.057 inch
OD.times.0.051 inch ID, axial pressure pneumatically applied by a
die for a time of 5 seconds, when the transition region 60 was
heated at 250.degree. C., was sufficient to result in a
substantially uniform outer diameter when formed about a
mandrel.
[0036] Referring now to FIGS. 7A-B, an alternative lead and method
are shown. In the depicted embodiment, the proximal section 310
having the first characteristic has substantially uniform outer and
inner diameters. The distal section 320 having the second
characteristic has a substantially inner diameter forming a lumen
340 and has first and second outer diameters. The first outer
diameter being smaller than the second outer diameter. The region
of the distal portion 320 having the first outer diameter extends
from the proximal end to a location 360 distal the proximal end.
The second outer diameter extends distally from the location 360.
The inner diameter of the proximal section 310 is substantially the
same as the first outer diameter of the distal section 320. The
outer diameter of the proximal section 310 is substantially the
same as the outer diameter of the distal section 320. The proximal
section 310 is disposed about the section of the distal section 320
that has the first outer diameter. The distal end of the proximal
section 310 is in contact with the proximal face of the shoulder
formed at the location 360 as the distal section 320 transitions
from the first outer diameter to the second outer diameter. In the
depicted embodiments, the proximal section 310 and the distal
section 320 are co-axial or axially aligned. A lap bad 300 is
disposed about the proximal 310 and distal 320 sections at the
region where the sections 310, 320 intersect. As discussed above
with regard to FIG. 6, the lead body is thermally formed while
axially compressive force is applied to the lap band to result in a
lead body having a substantially uniform outer diameter in the
transition section 60 defined by the length of the lap band 300 and
proximal and distal to the transition section 60 (see FIG. 7B).
[0037] In the embodiment depicted in FIG. 7, the portion of the
distal section 320 having the first outer diameter is co-extensive
with proximal section 310. Such an arrangement may be advantageous
relative to the arrangement depicted in FIG. 6 because the surface
area of the bond between the two sections 310, 320 is increased.
However, the processing steps or manufacturing costs associated
with a distal section 320 having two outer diameters as shown in
FIG. 7A may be increased relative to a distal section 320 as shown
in FIG. 6.
[0038] Referring now to FIG. 8, an alternative embodiment of a lead
body and a process are shown. In the depicted embodiment, a
proximal section 310 having a first characteristic and a distal
section 320 having a second characteristic are shown. The proximal
section 310 has a substantially uniform inner diameter forming a
lumen 330, and has first and second outer diameters. The first
outer diameter is smaller than the second outer diameter. A region
of the proximal section 310 extending from the distal end to a
location 350 proximal the distal end has the first outer diameter.
A region of the proximal section 310 extending proximally from the
location 350 has the second outer diameter.
[0039] The distal section 320 depicted in FIG. 8 has a
substantially uniform inner diameter forming a lumen 340, and has
first, second and third outer diameters. The first outer diameter
is smaller than the second outer diameter. The second outer
diameter is smaller than the third outer diameter. A region of the
distal section 320 extending from the proximal end to a first
location 360 distal the proximal end has the first outer diameter.
A region of the distal section 320 extending distally from the
first location 360 to a second location 400 distal the first
location 360 has the second outer diameter. A region of the distal
section 320 extending distally from the second location 400 has the
third outer diameter.
[0040] The inner diameter of the proximal section 310 is
substantially the same as the first outer diameter of the distal
section 320. The first outer diameter of the proximal section 310
is substantially the same as the second outer diameter of the
distal section 320. The second outer diameter of the proximal
section 310 is substantially the same as the third outer diameter
of the distal section 320.
[0041] In the embodiment depicted in FIGS. 8A-C, the proximal
section 310 is placed about the portion of the distal section 320
having the first outer diameter such that the distal end of the
proximal section 310 contacts the shoulder formed at the transition
from the first outer diameter to the second outer diameter of the
distal section 320 (see FIG. 8B). A lap band 300 is placed about
the portion of the proximal section 310 having the first outer
diameter and the portion of the distal section 320 having the
second outer diameter such that the lap band 300 contacts the
shoulder of the proximal section 320 formed at the transition from
the first outer diameter to the second outer diameter and contacts
the shoulder of the distal section 320 formed at the transition
from the second outer diameter to the third outer diameter (see
FIG. 8C). The lead body may then be thermally formed to produce a
lead body having a substantially uniform outer diameter along the
transition section formed by the lap band 300 and proximal and
distal to the transition region (see FIG. 8C).
[0042] Proximal and distal sections as described above that have
differing outer diameters along their length may be made by any
suitable process such as machining, molding or etching. With
reference to FIGS. 9-10, process schemes for forming the proximal
section 310 (FIG. 10) or distal section 320 (FIG. 9) depicted in
FIG. 8 are shown for purposes of example. In FIG. 9, illustrated is
a precursor polymeric tube 500 having a substantially uniform outer
diameter, which corresponds to the third outer diameter of the
distal section 320 (depicted in FIG. 8), and a substantially
uniform inner diameter (see FIG. 9A). As depicted, a portion of the
polymeric precursor 500 may be removed; e.g., by etching or
machining, or a series of steps made via a stretching and thermal
forming. In the embodiment depicted in FIG. 99, the portion of the
thickness from the proximal end to the first location 360 or the
second location 400 may be removed to form intermediates. In the
case of removal to the first location 360, a sufficient amount of
the precursor is removed to leave a section having an outer
diameter equivalent to the first outer diameter of the proximal
section 320. In the case of removal to the second location 400, a
sufficient amount of the precursor is removed to leave a section
having an outer diameter equivalent to the second outer diameter of
the proximal section 320. The intermediates may be further
processed; e.g. via etching or machining, to arrive at the
completed distal section 320 (see FIG. 9C).
[0043] With reference to FIGS. 10A-B, a precursor 510 is processed
such that a portion of the thickness of the precursor 510 is
removed from the distal end to a first location 350 proximal the
distal end to result in the proximal section 310.
[0044] Of course any other suitable method for making proximal and
distal sections as described herein may be employed.
[0045] Thus, embodiments of the METHOD FOR MAKING SMOOTH
TRANSITIONS BETWEEN DIFFERING LEAD SEGMENTS are disclosed. One
skilled in the art will appreciate that the present invention can
be practiced with embodiments other than those disclosed. The
disclosed embodiments are presented for purposes of illustration
and not limitation, and the present invention is limited only by
the claims that follow.
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