Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: APPARATUS AND METHOD FOR PERCUTANEOUS CATHETER
IMPLANTATION AND REPLACEMENT
INVENTOR: CHRISTOPHER H. PORTER, CLAUDE A. VIDAL, RUSS J. REDMOND,
BYRON L. MORAN, PAUL KALUZNIAK AND ABRAM D. JANIS
FIELD OF THE INVENTION
[0001) This invention relates generally to medical technology and more
particutariy
to a method and apparatus for implanting an elongate conduit, e.g., a catheter
or cable, so
as to extend through a patienYs skin for providing long term access to an
interior body
site. Embodiments of the invention are useful in a variety of applications,
e.g., in
hemodialysis procedures to enable a catheter to provide fluid access to a
patieni's central
venous system and/or nerve stimulation procedures in which a cable provides
access to
an implanted electric device.
BACKGROUND OF THE INVENTION
[0002] In a variety of medical procedures, catheters are implanted through a
patient's skin to provide long term access to interior body sites; e.g., blood
vessels and
organs. Unless adequate precautions are taken, infections and inflammation can
readily
occur at the catheter entry site. To mitigate such problems, a tissue
integrating cuff is
sometimes attached to the catheter and placed under the patient's skin to
resist infection.
Although. such a cuff can reduce the likelihood of infection, its presence -
increases the
difficulty of removing and/or repositioning an implanted catheter. More
particularly, it is not
uncommon for an implanted catheter to become damaged, e.g., dogged'or ldnked,
over
an extended period of use thus necessitating catheter removal and/or
replacement. When
this occurs, the cuff must be dissected thereby complicating and prolonging
the surgical
procedure.
[0003] The aforementioned Application 10/821,383 describes the use of a tissue
integrating structure on a percutaneously implanted medical device for
anchoring the
device and creating an infection resistant barrier around the device.
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SUMMARY OF THE INVENTION
[0004] The present invention is directed to a medical apparatus and method of
use
for percutaneously implanting an elongate conduit, e.g., a catheter or cable,
in a patient's
body in a manner which allows the conduit to be easily positioned,
repositioned, and replaced.
[0005] An apparatus in accordance with the invention includes an elongate
sleeve
comprising a wall surrounding an interior elongate -passageway. The passageway
extends from a sleeve proximal end to a sleeve distal end. The sleeve is
intended to be
percutaneously implanted through an incision in the patienYs sldn so that the
sleeve distal
end resides beneath the skin, i.e., subcutaneously, and the sleeve proximal
end resides
above the sidn. The sleeve outer peripheral surface carries a layer of porous
material,
e.g., a biocompatible mesh, as described in US Application 10/821,383,
intended to be
piaced just under the patienYs outer skin layer in contact with the dermis to
promote tissue
ingrowth for anchoring the sleeve and forming an infection resistant barrier.
The sleeve
passageway is dimensioned to snugly accommodate the outer surface of a conduit
(which
will hereinafter be assumed to be a catheter unless otherwise stated) while
permitting the
conduit to slide and rotate in the passageway relative to the sleeve. A
sealing device
within the sleeve extends around the catheter, e.g., near the sleeve proximal
end, to
prevent deleterious material from migrating into the patient's body along the
catheter outer
surface.
(0006] In one preferred embodiment, the sealing device comprises an annular
seal
formed of a soft flexible material, e.g., silicone, mounted within the
passageway of an
elongate rigid sleeve formed, for example, of titanium. The annular seal
comprises a
peripheral wall an inner surface surrounding an interior bore. At least one
annular flexible
nib on the annular seal inner surface projects radially into the bore for
sealing against the
catheter outer surface. Altematively, the sleeve can be formed of flexible
polymer tubing,
e.g., silicone, allowing an interior annular sealing nib to be formed integral
therewith.
(00071 A preferred embodiment also includes a locking member mounted at the
sleeve proximal end. The locidng member is configured so it can be readily
manipulated
by a physician to selectively define either a first, or unlocked, state, and a
second, or
locked, state. In the unlocked state, the conduit (e.g., catheter) is able to
slide and/or
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rotate relative to the sleeve passageway. In the locked state, a friction
force is applied to
the catheter to prevent relative movement between the catheter and the sleeve.
[0008] A preferred locidng member comprises a split ring formed of a soft
flexible
material, e.g., silicone, surrounding the catheter and dimensioned such that
its interior
bore in said unlocked state is sufficiently large to avoid restricting
catheter movement. In
the locked state, the split ring is radially compressed to frictionally grip
the catheter outer
surface to prevent catheter movement relative to the sleeve. The split ring
can be
compressed in various ways; e.g., by simply tying it with suture thread or by
using an
intemal or extemat clip, e.g., spring urged Gamp, to pinch the split ring.
[0009] In typical use, a physician will make an incision proximate to the
patients
chest or abdomen. A surgical tunneler tool is then typically inserted through
the incision to
form a subcutaneous tunnel to an interior site through which a standard
flexible catheter
can be inserted. In accordance with the invention, the catheter carries the
aforementioned
sleeve, annular seal, and locking member. The distal end of the sleeve is then
inserted
through the incision to locate the sleeve porous layer in contact with the
dermis just below
the patienYs outer skin surface. The sleeve proximal end may, at the
physician's option,
be extemally anchored to the patient's skin. With the locking member in its
unlocked
state, the physician is able to slide and/or rotate the catheter relative to
the sleeve and
locking member for optimum catheter positioning. When the catheter is property
positioned, the physician can then manipulate the locking member to the locked
state to
lock the catheter relative to the sleeve. With the sleeve thus implanted, the
patients
subcutaneous tissue will, over time, grow into the porous material to anchor
the sleeve
and form an infection resistant barrier. The porous material, and/or sleeve
interior, can be
coated or impregnated with constituents having antimicrobial and/or anti-
inflammatory
properties to promote healing, e.g., silver containing compounds or antibiotic
eluting
coatings and/or steroids.
[0010] In one preferred embodiment of the invention, a sheath of thin flexible
material is mounted around the sleeve and porous layer prior to use to avoid
tissue
damage to the patient as the sleeve porous layer is inserted through the
incision. The
sheath is preferably configured with a projecting tab which allows the
physician to readily
peel the sheath away, e. g, with one hand, as the sleeve is being implanted.
The sheath
preferably includes a preformed score or perforation line which can-be readily
fractured by
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the physician as he/she manipulates the tab after the sleeve has been inserted
through
the incision.
[0011] After the sleeve and catheter have been implanted, subcutaneous tissue
will
gradually grow into the porous layer to forrn an infection resistant barrier
around the
sleeve to prevent fluid and/or other deleterious material from migrating into
the body along
the sleeve outer surface. The annular seal functions to prevent deleterious
material from
migrating into the body along the catheter outer surface. A catheter assembly
in
accordance with the invention enables the physician at some later date (e.g.,
months) to
replace the implanted catheter while leaving the sleeve in place. To do this,
the physician
will typically insert a temporary guide wire through the old catheter and then
unlock the
locking member to allow the old catheter to be withdrawn along the guide wire
from the
sleeve proximal end. A new catheter is then slid over the guide wire through
the
implanted sleeve, seal, and locking member. After the new catheter is properly
positioned, the physician can then lock the new catheter in place by
manipulating the
locking member.
BRIEF DESCRIPTION OF THE FIGURES
[0012] Figure 1 is a schematic. representation generally depicting a catheter
assembly in accordance with the invention for percutaneously implanting a
catheter for an
exemplary hemodialysis application;
[0013] . Figure 2 is an isometric view of a preferred catheter assembly in
accordance with the invention;
(0014] Figure 3 is an exploded view of the assembly of Figure 2 showing a
catheter
in phantom together with a protective sheath, an anchor, a sleeve carrying a
of porous
material, an annular seal, and a locking member,
(0015] Figure 4A is a sectional view taken substantially along the plane 4A-4A
of
Figure 2;
[0016] Figure 4B is a sectional view taken substantially along the plane 4B-4B
of
Figure 4A showing the locking member in its unlocked state;
(0017] Figure 4C is a sectional view similar to Figure 4B showing the locidng
member in its locked state clamped by suture wire;
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j0018] Figures 4D and 4E show exemplary spring clips which can be aftematively
used for clamping the locldng member in its locked state;
[0019] Figure 5 is a plan view of the protective sheath of Figure 3;
[0020] Figure 6 is a sectional view taken substantially along the plane 6-6 of
Figure
particularly showing a preformed score line;
[0021] Figures 7-11 show successive steps in an exemplary procedure for
implanting and utilizing the catheter assembly in accordance with the
invention;
[0022] Figure 12 shows a cross-sectional view of the catheter assembly as
implanted with the porous layer positioned subcutaneously adjacent the
patient's dennis;
[0023] Figure 13 is a cross sectional view through an altemative catheter
assembly
embodiment showing its locking member in its unlocked state;
[0024] Figure 14 is a sectional view taken substantially along the plane 14-14
of
Figure 13;
[0025] Figure 15 is a sectional view similar to Figure 13 showing the locidng
member in its locked state; and
[0026] Figures 16 is a sectional view taken substantially along the plane 16-
16 of
Figure 15. '
DETAILED DESCRIPTION
[0027] Various medical regimens relating, for example, to hemodialysis drug
infusion, plasmapheresis, etc., use a percutaneously implanted conduit for
conveying fluid
and/or electric signals to/from an interior body site. The present invention
is directed to a
method and apparatus for facilitating the implantation and utilization of a
percutaneous
conduit (e.g., catheter) and for facilitating the positioning, repositioning,
and replacement,
or exchange, of the catheter.
[0028] Figure 1 schematically depicts an assembly 20 in accordance with the
invention for percutaneously implanting a catheter 22 through an incision 24
in a patient
26 undergoing an exemplary hemodialysis procedure. In such a procedure, a dual
lumen
catheter 22 is typically used with the two lumens being respectively coupled
to separate
exterior flow couplers 28 and 29.
[0029] Attention is now directed to Figures 2-4 which depict a preferred
catheter
assembly 20 in accordance with the present invention. Figure 3 best shows the
primary
elements of the assembly 20 including sleeve 30 carrying a porous layer 31, a
sealing
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device 32, and a locldng member 33. The assembly 20 also preferably includes a
protective sheath 34 and an anchor 35 for anchoring the assembly 20 to a
patients outer
sidn surface.
[0030] The sleeve 30 preferably comprises a substantially rigid tubular
titanium
member formed by a peripheral wall 36 (Figure 4) having an outer surface 37
and an inner
surface 38. The inner surface 38 surrounds an interior passageway 39 extending
axially
from a sleeve first, or proximal. end 40 to a sleeve second, or distal, end
42.
[0031] The sleeve 30 is shown mounted on a catheter 22 extending axially
through
the passageway 39. The catheter outer surface 44 and passageway wall surface
38 are
closely dimensioned but with sufficient clearance therebetween to enable the
catheter to
slide axially and rotate in the passageway 39. The sleeve 30 proximal end 40
is
preferably enlarged at 45 to form an interior recess 46 for accommodating the
sealing
device 32. The sealing device 32 preferably comprises an annular member 48
formed of
a soft flexible material, e.g., silicone. The seal member 48 defines an inner
peripheral
surface 50 surTounding an interior bore 52 which is contiguous with sleeve
passageway
39. At least one flexible annular nib 54 extends radially into the bore 52 for
contacting and
sealing against the catheter outer surface 44.
[0032] The enlarged sleeve end 45 has an outer peripheral surface 56
dimensioned to closely fit into bore 58 of anchor 35. The anchor 35 comprises
a base
portion 60 supporting a ferrule portion 62 which defines the bore 58. The
anchor- base
portion 62 is provided with holes 64 to facilitate the suturing of anchor 35
to the patients
outer skin.
[0033] The locking member 33 preferably comprises a split ring formed of soft
flexible material, e.g., silicone. More par6culariy, the locking member 33 is
comprised of a
peripheral wall 66 having an outer surface 68 and an inner surface 70
surrounding an
interior bore 72. The wall 66 is longitudinally split at 74. The wall outer
surface 68 is
preferably provided with one or more strap pads 71 for securing the locidng
member 33 to
the anchor 35 and/or sleeve 30 using one or more straps 76. The locking member
outer
wall surface is provided with a proximal annular groove 80 for accommodating
suture
thread or an appropriately shaped spring clip which can be used by the
physician to
compress the locking member 33 around the catheter 22. Preferably, a= distal
annular
groove 82 for accommodating suture thread is also provided.
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-[0034] The locking member 33 is configured so that in its natural unlocked
state
(Figure 4B), the interior bore 72 is sufficiently large to permit the catheter
22 to slide axially
and rotate in the bore 72 and through the sleeve passageway 39. The physician
can
compress the locking member wall 66 around the catheter to frictionally engage
the
= locking member inner surface 70 against the catheter outer surface 44' to
thus lock the
catheter outer surface 44 to the sleeve 30 to prevent any relative movement
therebetween. This locked state can be maintained by tying suture thread 83
around the
locking member wall in groove 80. Of course, the thread can be readily cut
when it is
desired to release the locked state to allow the catheter to be repositioned
and/or
replaced. Figures 4D and 4E depict exemplary spring dips which can be used in
the
groove 81 is also provided.
[00351 The locking member 33 is configured so that in its natural unlocked
state
(Figure 4B), the interior bore 72 is sufficiently large to permit the catheter
22 to slide axially
and rotate in the bore 72 and through the sleeve passageway 39. The physician
can.
compress the locidng member wall 66 around the catheter to frictionally engage
the
locking member inner surface 70 against the catheter outer surface 44 to thus
lock the
catheter outer surface 44 to, the sleeve 30 to prevent any relative movement
therebetween. This locked state can be maintained by tying suture thread 82
around the
locking member wall in grooves 80, 81. Of course, the thread 82 can be readily
cut when
it is desired to release the locked state to allow the catheter to be
repositioned and/or
replaced. Figures 4D and 4E depict exemplary spring clips 83 which can be
altematively
placed in the grooves 80, 81 in lieu of thread 82 for clamping the locking
member in its
locked state.
[0036] The protective sheath 34 is formed of thin flexible tubular material
(e.g., .010
wall FEP tubing) and is intended to be mounted around sleeve 30 and porous
layer 31
prior to use -to avoid injuring the patient's tissue when the sleeve distal
end 42 is inserted
through the incision 24. As will be further discussed hereinafter, the sheath
34 is removed
from the sleeve 30 by the physician after the sleeve and porous layer have
been inserted
through the incision.
[0037] More particularly, the sheath 34 is preferably configured as a
substantially
tubular, e.g., cylindrical, body 86 having a distal collar 87 and a proximal
elongate pull tab
88. An outwardly tapering section 89 extends from the collar 87 to the main
body portion
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86. Note that the collar 87 and distal portion of section 89 have a diameter
smaller than
that of the porous layer 31. For example only, the sleeve 30 may have an outer
diameter
of .250 inches, the porous layer 31 an outer diameter of .310 inches and the
collar 87 an
inner diameter of .193 inches. An axially oriented score, or perforated line
90 is prefonned
through the collar 87, the tapering section 89 and the body portion 86 to
facilitate the
physician peeling the sheath 34 from the sleeve 30. Note in Figure 4A that the
sheath fits
tightly around the periphery of sleeve 30 and porous layer 31 and that the
tapering section
89 is positioned distally of the porous layer 31. In use, the physician is
able to readily peel
the sheath from the sleeve with one hand by rolling, or winding, the elongate
tab to pull
the sheath axially in a proximal direction. Peeling occurs because as the
sheath is pulled
proximally, the tapering section 89 and collar 87 have to move past the larger
diameter
porous layer 31 which action causes the sheath to tear along score line 90
allowing it to
be easily stripped from the sleeve 30.
[0038] In the preferred catheter assembly illustrated in Figures 2-4A, the
sleeve 30
comprises a rigid titanium tube characterized as follows:
overall length : 1.135 inches
proximal end 45 length : .250 inches
passageway 39 ID : .200 inches
end 45 ID : .313 inches
sleeve 30 wall thickness : .025 inches
porous material 31 OD : .304 inches
nib 54 ID : .170 inches
[0038] In an altemative embodiment, the sleeve can be similarly dimensioned
but
instead of being formed of a rigid material such as titanium, can be formed of
a flexible
material such as silicone. In such an embodiment, the annular sealing nibs can
be
integrally formed with the sleeve.
[0040] As has previously been mentioned, in use, dermis tissue grows into the
porous layer 31 to form a barrier preventing deleterious material from
migrating into the
patienfs body.along the sleeve outer surface 37: The aforementioned seal
member 48
acts to prevent migration of deleterious material into the body along the
narrow gap
between the catheter outer surface 44 and the sleeve inner surface 38.
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[0041] Figures 7-12 schematically depict successive steps in an exemplary
procedure for implanting the catheter assembly 20 shown in Figures 1-6.
[0042] Figure 7 shows the use of a conventional tunneler tool 200 being
inserted
through a patienYs incision 24 to form a tunnel through which the distal end
of the catheter
22 is pulled by the proximal end of tool 200.
[0043] Figure 8 shows the catheter assembly 20 with the sleeve distal end 42
and
protective sheath 34 being inserted through the incision 24.
[0044] Figure 9 shows the catheter assembly 20 inserted further into the
incision
for positioning the porous layer 31 just beneath the epideirmal skin layer and
adjacent to
the dermis layer. Note the protective sheath tab 88 extending outwardly from
the sleeve.
[0045] Figure 10 shows the protective sheath 34 being peeled away (as a
consequence of the physician pulling tab 88) from the sleeve 30 to directly
expose the
porous layer 31 to the patient's dermis.
[0046] Figure 11 shows the anchor 35 sutured to the patienYs skin to thus
securely
retain the sleeve proximal end 40 the locidng member 33 in place.
[0047] Figure 12 shows a cross-section of the installed catheter assembly 20
with
the porous layer 31 contacting the patient's dermis 85 to promote tissue
ingrowth.
[0048]. After initial implantation of the catheter 22 as depicted in Figures 7-
12, it is
sometimes desirable to reposition the catheter for more effective treatment
and/or to
reduce= patient discomfort. Such repositioning can involve slightly adjusting
the position
and/or orientation of the catheter distal end and is achieved by unlocldng the
locbng
member 33 and then sliding the catheter into or out of the sleeve 30 and/or by
rotating the
catheter in the sleeve.
[0049] It is further pointed out that with the locking member 33 in its
unlocked state,
an implanted catheter can be fully withdrawn through the sleeve proximal end
for
replacement by a new catheter. Although different technique can be employed,
it is
contemplated that the physician will thread a guide wire through the old
catheter prior to
withdrawing it. The new catheter is then threaded along the guide wire and
through the
sleeve. When the new catheter is properiy placed, the guide wire is typically
withdrawn.
[00s0] Atterrtion is now directed to Figures 13-16 which illustrate a catheter
assembly 240 in accordance with the invention employing an altemative locking
member
242. Figures 13, 14 show the locking member 242 in its unlocked position and
Figures
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15, 16 show the Iocidng member 242 in its locked position_ The locidng member
242 is
comprised of a substantially rigid tubular body 244 having a proximal end 246
and a distal
end 248. The proximal end 246 defines a central bore 250 configured to align
with the
interior bore 52 of seal 32 and passageway 39 of sleeve 30. The distal end 248
of body
244 comprises an enlarged cuff 251 intended to fit around and be secured to
the enlarged
end of sleeve 30 as shown in Figures 13, 14.
[oo51] An apertured washer 252 is mounted in cuff 251 adjacent to the proximal
end of sleeve 30 and spaced from the proximal end 246 of body 244 to define a
recess
253 therebetween. A locking. element, or ring, 254 is mounted in the recess
253 for
movement perpendicular to the axis of body 244. More particulariy, the ring
254 is.
movable between an unlocked position (Figure 13) where the ring bore 256 is
aligned with
the bore 250 and a locked position (Figure 15) where the ring bore 256 is
misaligned with
bore 250. In the locked position, the ring 254 bears against the outer surface
44 of
catheter 22 to prevent catheter movement relative to sleeve 30.
[0052] In the exemplary embodiment depicted in Figures 13-16, the position of
the
ring 254 is determined by a manually operable lever 260 hinged at pin 262. The
lever 260
carries a projection 264 for bearing against ring 254. When the lever 260 is
in its
counterclockwise position (Figures 15, 16) projection 264 forces ring 254
against the
catheter 22 to prevent it from moving relative to sleeve 30. On the other
hand, when the
lever 260 is moved dockwise to the position shown in Figures 13, 14, the force
exerted by
ring 254 on the catheter is relieved pertnitting the catheter to rotate and
slide axially
relative to sleeve 30.
[0053] The lever 260 camies a detent mechanism 270 for latching the lever in
the
locked position of Figure 15, 16. The exemplary detent mechanism 270 is
comprised of
arcuate sprint arms 272, 274 which are configured to releasably snap around
anchor 276
to latch the lever 260 in the locked position. The locking member 242 can be
readily
moved to the unlocked position by manually pivoting the lever 260 clockwise to
the
unlocked position (Figures 13, 14).
[0054] From the foregoing, it should now be understood that a catheter
assembly
has been provided particularly configured to facilitate the positioning,
repositioning, and/or
replacement of a percutaneously implanted catheter. Although only a limited
number of
structural embodiments have been described, it is recognized that various
modifications
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and alterations will occur to persons skilled in the art which fall within the
spirit and
intended scope of the invention as defined by the appended claims.
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