Note: Descriptions are shown in the official language in which they were submitted.
CA 02246434 1998-08-12
WO 97/28840 PCT~,5'~25~_
PROSTATIC TISSUI~ E~P~NDE~I~
Back~lound of the Invel1tiol1
Tllis invention rel.ltes lo medical tissue expansion, and more
5 particularly it pertains lo a prostatic tissue expander balloon catl1eter for expanding
the prostatic urethra over a period of time. Inflation balloon pressure is m;lint,~in~-d
by valves in the inf~atiol1 lumens. Tlle tissue expander catheter is uscd to expand the
prostatic urethra for the treatment o~ BP~I (Benign Prostatic I-Iypertrophy).
By far the most common prostate problem is enlargement of the
10 gland, or BPH. Common in men over 50, it is sil11ply excess grow~h in the
innermost part of the prostaLe. The urelhr~ tl1at empties ~hc bladder runs tllrough
the middle of the prostate. Tlle more the prostate enlarges, the more the flow of
urine is constricted, causing a variety of uncomfortable symptoms when one tries to
urinate.
The surgieal solution to prostate enlargement has become the most
common surgery eonfronting adult males today. It is known as Transurethral
Resection of ehe Prostate (TURP). The Tral~s,ll~;tllldl Resection procedure is carried
out tllrough a narrow tube-lil;e instrument ealled a rP~ectoscope, whicl1 is inserted
into the urinary eanal via the penis. Working through the resectoscope, the urologist
carves out a portion of the prostate to enlarge the urinary passageway.
A reeent alternative to TURP prostate surgery is the use of a small
balloon, temporarily inserted into the urinary canal, precisely positio~ed whcrc the
urethra passes tllrough the prostate, then inflated (for just mtnllt~s usually) to enlarge
the urinary passageway where it is constricted by the enlarged prostate. During the
1980's, this eoncept in a different proeedure won wide aeceptance among
cardiologists, who use a tiny balloon catheter to enlarge clogged blood vessels
through a procedure called "angioplasty". In the case of the prostate, the procedure
is known as "transcystoscopic uretl1roplasty". It is the urethra (not an arter)~) that is
blocked, and it is the flow of urine (not blood) that is obstructed.
The C)ptilume Prostate Balloon Dilator manufactured by American
Medical Systems is a dilator of the foregoin,, type for use in transcystoscopic
urethroplasty. It has a non-distensible, single size, dilation balloon (~ me~ r
30ml11 [90Fr], lengtl1: 80mn1) located near the tip of a catheter shaft. A transparent
CA 02246434 1998-08-12
W O 97/28840
PCT~US96/02500
locating balloon is mounted proximal to the clilation balloon. The balloons arc
enclosed in a PTFE shcath for placcment in the urethra. This type of dilator is more
fully described in U.S. patents 4,932,956 and 4,932,958 to Ready.
The shcatll enclose(l catheter of the dilator is inserted into the urethra.
5 The balloons are moved out of the sheath and into worL~ing position with the locating
balloon in ~he bulbous urethra, resting against lhe e~ctcrnal sphinctcr. Positioning is
accomplished by palpation, fluoroscopy or by placing a rod lens along sidc o~ the
PTFE shealh and looking through the transparent locating balloon to coniirlll that the
dilation balloon is in the proper location. The dilation balloon is inflated up to 60
10 PSI for 10 to 15 mimlteS, after which both balloons are deflated. The catheter is
then drawn back h1to the sheath and rcmoved.
In order to improve thc rcmoval charactcristics, and thereby increasc
paticnt comfort, thc dilator utilizes a PET balloon dcsign which llas a layer ofsilicone over the PE:T balloon with a coating of lubricant betwcen thc layers. The
15 smooth finish and the elastic ~lupe~lies of the silicone permit easier removal of the
deflated balloon.
Anothcr knoyln device is the Dowd cathetcr m~m-l~ct~lred by
Microvasive, Inc., which also has a non-distensiblc dilation balloon measuring
30mm in (li~met~r and 85mm in length. A palpation nodule is mounted proxin1al of20 the balloon near the proximal cnd of the shaft. A knob is affixed to the shaft to
provide a means of m~int~ining the position of the balloon during inflation. In use,
the Dowd catheter is m~ml~lly inserted without benefit of introducers or other
sheaths. Throughout the entire procedure, the physician has a finger in the rectum
against the nodule to judge positioning of the catheter. The balloon is inflated up to
25 60 PSI for the duration of the 10 to 15 minute procedure. During this time the
urologist must m~int~in traction of thc shaft to prevent the balloon from migrating
into the bladder. The balloon is removccl following deflation by twisting and
pulling.
Anotl1er known device is the Uroplasty T(:~U design m~mlf~tnred by
30 ~dvanced Surgical Intervention. It Çcaturcs a Folcy Balloon at its distal tip and a
non-distensible dilation balloon mounted just proximal to the Foley balloon. Tl1e
dilation balloon has a di~meter of 251mn (75Fr), and is available in lengths from
15mm to 55mm.
CA 02246434 1998-08-12
W~ 97J2884~
PCT~US96/02500
-3
A special "calibration" cathcter with distance graduations on its shaft
is inserted throu~h a disposable introducer slleatll whicll contains ~ rod lens for
viewing tlle graduation adjacent to tllc sphincter. The calibration catlletcr isrcmoved ancl a dilation catheLcr havin~ c propcr length balloon is installcd. The
5 Foley balloon on the dilation cathcter is inflated in the bladder and exact placcment
is confirmed through the lens. ~he dilation balloon is inllated at up ~:o 45 PSI for 10
to 15 minutes. Migration is not possible becausc the catheter is anchorcd by having
one balloon on each side of the bladder neck. Upon deflation, the balloon is
rcmoved by wi~:hdrawing it through the introducer sheath thereby prevcnting furtllcr
10 trauma to thc urethra. Rosenbluth, U.S. Patcnt Nos. 5,007,898 and 5,030,227, an(l
Klein U.S. Patent Nos. 4,660,560 and 5,002,558 dcscribe such devices and are
incolporated herein by reference in their entirety.
Balloon dilation of the prostatic urethra may produce a
commissurotomy or tearing, which is considered by some to enhancc the results.
15 Bleeding frequently accompanies the procedure. A catheter may be placed
immediately following the dilaeion to allow the patient to void comfortably.
Unfor~unately, it has been ,found tllat tllc beneficial rcsults from treatment as
mentioned above are fairly sllort lived for the ba~loon dilation procedurc.
As noted above, transcystoscopic urethroplasty (TCU) or transurethral
20 balloon dilation of the prostate (TUDP) can and in many cases does rupture the
urethra (commissurotomy). Even so, tlle pro~ressive development of this technique
has tended toward the use of larger and larger diameter dilation balloons. See the
paper entitled "I:)ilation of the Prostatic Urethra with 35mm Balloon" by McLaughlin
et al., which appeared in the BRlTlSH~OlJl~N~l, OF UROLOGY(1991), 67, 177-
25 181.
A procedure known as tissue expansion is also known in tlle mçrlic~lart. In tissue expansion procedures, a temporary device for expanding or stretching
skin and tissue is placed within the body and is cxpanded over an PxtPnrled period of
time and left in place until the tissue or skin stabilizes to an enlar~ed and permanent
30 size. This procedure is used to treat burn victims and for breast rcconstruction. Scc
U.S. Patents 4,643,733 and 4,217,889 for examplc. No one to date has thought to
apply the concept of tissue expansion to the TCU or TUI)P procedure, lltiii7.insT a
CA 02246434 1998-08-12
. W O 97/28840 PCT~US96tO250
--4-
distcnsible balloon, as a substitute for the presently practiccd proceclure lltili7ins7
short time balloon dilation with a non-distensible balloon.
Summary of the Invention
S In summary, this invention provides means, including a distcnsiblcballoon, for applying tissue expansion to the alleviation o~ obstructivc prost~ti~m
The invention may be expressed in terms of both an apparatus and a method. Tissue
Expansion as used in this invention relates to relativcly long term gradual expansion,
preferably applied in gradual steps over a period of time, to stabilize tissue growtll.
On tlle other hand dilation as used in the prior art relates to short tcrm somcwhat
drastic expansion and is readily distinguished ~rom this invention.
This invention offers several advantagcs ovcr the prior art including
thc followin~:
Dilation balloon devices tr~nmz-~ic:~lly and temporarily dilate the
prostatic urethra with mixed results reported over the short term (up to 18
months). Long term results are unavailable but expectations are low. On the
oLher hand, the tissu,e expansion ~pproach of thc prcscnt invenlion, occurrin~
over an extcndcd pcriod, which allows physiological compcnsation and tissuc
generation, should yield good long term results.
Tissue expansion is less traumatic and inherently requires less
volumetric displacement than dilation.
The expansion and expansion rate of the prostatic urethra in
accordance with the tissue expansion approach of this invention is ~ased on patient
eomfort and tolerance. A eommissurotomy can be avoided and instead tissue
expansion will occur. When full expansion is achieved the tissue expander may be left in place for a few days to stabilize the tissue expansion.
There has been noted in other devices, some tendency for a dilation
balloon to migrate into the bladder. In some cases, damage to the sphinrter or
bladder neek has been reported leading to inContin~nre and retrograde ejaculation.
The tissue expansion teçllnique minimi7rs the potential for such problems.
The procedure is an out-patient one versus a hospital procedure.
A choice of multiple balloon sizes will accormnodate individual
anatomy.
CA 02246434 1998-08-12
WO 97~8840
PcT/Irs96ro2s~w
The use of a sheath or introducer is not required.
Distensible balloons as suggested for use in tl1is invention increase in
size in proportion to the inflation pressure and shrink or constrict approximalely to
their original shape upon deflation; non-distensible balloons as used in the prior art
S are of fixed sur~ace area (the envelope does not readily shrink on (leflation) and can
cause trauma upon removal.
Significant features of this invention are as follows. Tissue expansion
is minim~l and may take place at a gradual rate. In the previous applications ofballoon dilation catheters for tlle tre~mrnt of BPM, the balloon was inflated for only
a short time; The longest period of dilation suggested is describecl in the Kleill
patent 5,002,~8, abstract and line 30 of Column 6, as a period of "one hour or
more". The present invention teaches that inflation extending ovcr much longer
periods, perllaps days or even weeks, should be used to accomplis~l tissue expansion.
This gradual expansion, which is accomplished by a~lding small amounts of the
expanding solution to the balloon over a period of time, minimi7rs discomfort.
When the procedure is completed, tl~e prostatic urethra has been enlarged, with
relief of the symptoms of BPH without sisgnific~ trauma.
Brief nescription of the Fi~ures
Various objects of the present invention and many of its attendant
advantages will be more readily apl~eciaLed by reference to the following detailed
description when considered in connection with the accompanying drawings, in
which like reference numerals desi~n~t~ like parts thloughout the Figures thereof
and wherein:
Figure 1 illustrates a pel~eclive view of a prostatic tissue e~n-ler
according to the present invention;
Figure 2 illustrates a lon~ihl~lin~l cross-sectional view of a ma~or
portion of the proximal end of the tissue expander catheter of Figure 1 taken along
line 2-2 thereof;
Figures 2a and 2b are longihlrlin~l cross-sectional views of the valves
24 and 28 taken along lines 2a-2a and 2b-2b, respectively in Figure 2; Figure 2c is a
cross-sectional view of the 2b valve taken along line 2c-2c in Figure 2b;
CA 02246434 1998-08-12
W O 97128840
rCT/US96/02500
~igure 3 illustrates a cross-scctional view of thc cathctcr shaft taken
along line 3-3 of Figure l;
Figure 4 illustrates thc inLlation of the balloons of thc lissuc expander
shown in I~igure l;
~igurc 5 illustrates a longitudinal scctional vicw of thc distal tip Or tllc
catheter taken along line 5-5 of Figure 1 and includes a palpated nodule ~2 on the
catheter shaft;
Figurc 6 is a cross-scctional view along linc 6-6 of ~;igurc 5;
Figure 7 is a cross-sectional view alon~ line 7-7 Or Figure 5;
l~igurc 8 illustrates the uretllral placcmcnt of the distal tip, all(l tllc
balloons of the tissue cxpancler of the invention with respect to llle bladcler and thc
prostate gland;
Figure 9 shows an cmbodilllcnt Or a pump to be used with ~hc catheter
dcvicc of the invention; Figure 9a is an cnlarged vicw of a. portion of tlle l~ump;
Figure lO shows a modified structurc for the pump of ~igurc 9; and,
Figure 11 shows a syringe with prcssure in-licatc)r for use with thc
pump of Figure 9.
Detailed Description of the Preferrcd Emhodiments
The preferred prostatic tissue expander of this invention as illustrated
in Fi~ure 1 includes two inflatable balloons: A first positioning balloon, preferably
a ~oley balloon, located at the distal tip and a second balloon, a ~lictell~ihle tissue
expansion balloon, located proximal of the first balloon. Preferably, the tissueexpansion balloon will be available in a range of lcngths and sizes for each patient.
2~ Being ~ t~n.ci~le, the rli~m~ter of the tissue expansion balloon increases as internal
pressure is raised by inflation. The cathetcr shaft upon which the balloons are
mounted is of a flexible material and may be reinforced in the region of the tissue
expansion balloon to prevent occlusion of the catheter lumens, if rcquired. The
cathcter shaft of this embodiment is equipped with two lumens to connect thc
balloons to pressure ret:l-nin~ valves located at the proximal end of the device. A
center lumen is also provided having a proximal connector to attach to a urine
collection device, such as a leg bag.
CA 02246434 1998-08-12
W097/2~840
PCT~US96/02500
-7-
Insertion of the device into the urethra is sin1ilar to Lile procedure used
Wit~l a standard Foley catheter: The shaft is lubricated and m~nll~lly inserted until
the dist~l tip is in the bladder. Tlle positioning ballooll is inflated and mild traction
is applied wllilc thc tissuc expansion balloon is E~artially intlatcd. With l~ h~lloolls
inflatcd, ~he devicc is anchorcd in p5acc. Sincc no part of thc sccond balloon is ill
the bladder, there is no tendency of the device to migrate into the bladder. Inflation
of thc second balloon may be increasecl gr~dually ovcr ~ period of d~ys or wecL;s to
effect tissue expansion. After the expallsion reaches a desired }evcl, the balloon may
be lcft in placc while thc prostate adjusts to the incrcascd sizc oF tlle ureLhra and
10 establishes tissue stability. Upon completion of the trc~men~ the balloons are
deflated and returncd to tlleir original ~liametcr, ~pproximately that of the device
sha~t. The device is then withdrawn from the urethra.
Referring now to Figure 1 in dctail, tllcre is sllown a p~rspcctivc vicw
of a prostatic tissue expander, gencrally in~ir~tPd at I0, including a plastic, lumened
catheter shaft 12, a distal end gencrally inrlic~tP~l at 14 having a Folcy balloon 16,
distensible lissue expander balloon 18, and a urine port 20. The proximal end o~ tl~e
prostatic tissue expander 10" gencrally indicated at 21, includes a Foley balloon
inflation port generally in~ ted at 22 and an associated inflation control valve 24, a
distensible tissue ~oxpan-~er balloon inflation port gcnerally in-lica~d at 26, an
associated inflation control valve 28, and a connector generally inrlic:~tPd at 30 for
coupling the device to a urine collection bag (not shown). An inflation syringe
generally indicated at 32 may be used to inflate the Foley balloon 16 as shown and
the distensible tissue expander balloon 18 by connection to the proper inflation port
22 as shown or 26 by means of, for example, Luer fittings. Such fittings are well
};nown in the art.
Valves 24 and 28 may in the most basic form of this invention be
simple manual "off" "on" valves for selectively infl~ting and deflating the balloons.
Optional valving arrangements may be used if dcsired and preferred valves are
described fully hereinbelow.
Catheter shaft 12 is formed o~ a material which is nexiblc enough to
follow the bends in the urethra on insertion of device 10. The material should be
rigid enough, however, to allow device 10 to pass over any obstructions within thc
urethra. (~:lth~tpr shaft 12 may be composed of or covered by a biocompatible
CA 02246434 1998-08-12
W O 97/28840 PCT~US96/~2500
-8-
materi~}l to avoid irritation and complieation in the urethra. Such catheters and
covering materials are well known in the art. Suitable biocompatible materials
which may be l~lade inLo lumencd Lubillg ol suiL~ble lle~;ibilily and rigic ily lor sllalL
12 are, ror example, silicone, latex, polyvinylclllori(le alld polyuretllallc, silicone
5 presently being most preferred.
Balloon 16, the positioning balloon, is formed of a biocompatible
material such as silicone or C-Flex, a styrene ethylene butylene styrene modified
bloek copolymer, and is preferably of the Foley type.
Balloon 18, the distensible tissue c~p~nrlinsJ balloon, is also folmecl of
10 biocompatible low modulus elastomer material such as latex, silicone or ~-~lex,
being of tl1e distensible type iLs diameter can be varied on inflation over a range of
r~i~meterS. Distensible balloon construction is known in the art and need not bedescribed here in detail. In some in.ct:lnres, balloons o~ controlled distensibility may
be desired and in such inct~nres a higl1 modulus elastomer such as polyurethane may
15 be used or reinforcement may be incorporated into a balloon of low modulus
elastomer in accordance with known teehniques.
Reference is ,now made to Figure 2 which shows a cross-sectional
view of the major portion of the proximal end generally inrlic~ted at 21 of the tissue
expander 10 taken along line 2-2 of Figure 1 in which all numerals correspond to20 those elements previously described. Proximal end 21 il1cludes a branched body 34
having a central urine drainage lumen 36 flanked by lumens 38 and 40, all of whieh
extend longitudinally through the catl~eter shaft 12 of Figure 1. Urine drainagelumen 36 is a requisite feature of the device since the device is in place over a
period of time e~ nclin~ from days to weeks and provision must be made for
25 urination during that extended time. Lumen 38 term;n~ s proximally in a ~unnel-
like end portion 39 and interconnects the positioning balloon 16 inflation port 22 and
inflation control valve 24 (see l~igures 1 and 2) to positioning balloon 16 through a
balloon port 44 (seen in Figures 4 and 5). Lumen 40 connects the di~ten~ible tissue
expander balloon inflation port 26 and intlation control valve 28 (see Figures 1 and
30 2) to the distensible tissue expander balloon 18 through a balloon port 48 (seen in
Figures 4 and 5). Lumens 38 and 40 likewise may terminate in funnel-like branched
end portions 39 and 41 respectively.
CA 02246434 1998-08-12
WO 97/28840
PCT/US96~0ZSW
Valves 24 and 28 are shown in a preferrcd construction in Figures 2b
and 2a, respectively and in 2c. Valve 24 is sho~vn with a standard tapcred Leur
fitting by means of which the syringe pump of Figure 1 is :ltl~cllr~i to port 22, as is
known in thc art. Because thc a~l<~cllmcllt is of rclativcly short duratioll, ~llis
arrangement is considered to be satisfactory allhough not critical. On the otherhand, valve 28 includes a hub fitting 29, another standard Leur fitting knowll in Lhe
art, because a pump ( as will be described further hereinbelow) is ~tt~rl-ed ~o port
26 for long term association with the device. In other respects, the two v~lves 24
and 28 are es.se-nti:llly i(le-nti~l and include the same elements, all of which are
preferably formed of any suitable thermoplastic. Many speci~ic materials will bereadily apparent to those familiar witll the medir:ll device art, including matcrials
otller than thermoplastics.
Both valves include valYe bodies 31, a retaincr 33 which hol(ls tl~e
valve body in place as shown in the respective branch of body 34. Valve bodies 31
respectively define the inflation ports 22 or 26 and contain a flexible multi-fingered
- valve actuator retainer 35 and valve actuator rod 43. ~ctuator rod 43 seats against
seat 45 to normally close t4e valve an(l is held in place normally by actuator retainer
35 as shown. When a syringe or other device is inserted into the respective port 2
or 26 and pushes against actuator rod 43 it is moved against the bias provided by the
actuator retainer 35 to move away from seat 45 thus openin, the valve.
Figure 3 illustrates in cross-sectional view the lltmenf~cl catheter shaft
12 taken along line 3-3 of Figure 1 where all numerals correspond to those elements
previously deseribed. Illustrated in particular are tl1e inflation lumens 38 and 40
fl~nlcing the central urine drainage lumen 36.
The inflated distensible tissue expander balloon 18 and the positioning
baIloon 16 at the distal end 14 of the prostatic tissue expander l0 is illustrated in
Figure 4 where all numerals correspond to those elements previously described.
Reference to Figures 5, 6 and 7 provides an illustrated sectional views
of the distal tip portion 14 of tissue expander 10. In Figure 5 the cross-section is
30 taken longit~ in~lly al1d parallel to line S-S of Figure I in which the positioning
balloon 16 and the ~listen~ible tissue expander balloon 18 are slightly expanded and
in which all numerals correspond to those elements previously described. In Figure
6 the cross-section is tal;en along line 6-6 in Figure 5 of the partially innated
CA 02246434 1998-08-12
W O 97/28840 PCTrUS96/02S00
-10- ,
distcnsiblc ~issuc cxpallclcr 17allooll 18 of I~igurc 5 in whicll all llumcrals corrcspon~l
to those elements previously described. In I;igure 7 the cross-section is taken along
line 7-7 of the partially inflated Foley balloo1l 16 of Figure 5 where all numerals
correspond to those elements previously describcd. Illustrated in particular is a
5 reinforcellle11t tube 50 located in tlle urine lumen 36.
In these Figures 5-7 the positioning balloon 16 (preferably the Foley
type) and rli.ct~ncible tissue expandcr balloon 18 are shown bondcd to or oLhcrwise
suitably secured around and about the lumrnPd catheter shaft 12 in commllni~ tion
with their respective balloon ports 44 and 48. Inflation lumcn 38 is portcd to the
interior 42 of the positioning balloon 16 by port 44. Inflation lumen 40 is ported ~o
the interior 46 of the distensible tissue expander balloon 18 b~ port 48. Optional
reinforcement tubes 50 and 52, l1aving interior lumen passageways 50a and 52a
respectively, are located and suitably sccured in the urine lumen 36 within the Foley
balloon 16 and the distensible tissue expander balloon 18, respectively. These may
be of a higher modulus elastomer, a thermoplastic or metal. Pressure by fluid flow
through the lumens is exerted against tlle inner ~valls of balloons 16 and 18 toexpand the balloons. Pressure is also exerted inwardly upon tlle exterior of lumened
catheter shaft 12. Reinforcement tubes 5~ and 52 prevent closing of the urine path
by pressure exerted upon the exterior of the lumened catheter shaft 12 and extend
proximally from urine port 20 along urine lumen 36. Thus, a continuous urine
passageway, including the urine lumen 36 and interior lumen passageways 50a and
52a is m:lin~inf~cl during any state of balloon inflation. Otller arrangements for
achieving this end will be apparent to those familiar with the catheter art.
Also, a locating nodule 62 as earlier referred to may be included on
catheter shaft 12 as shown in Figure 5 and as is known in the art.
As can be seen from the preceding description, one basic embodiment
of the invention comprises the following elements:
A. Tip with drainage eyelet(s) - 14 and 20;
B. Positioning balloon - 16;
~. Expander balloon - 18;
D. Triple lumen catheter shaft - 12;
E. Urine drainage funnel - 37;
F. Inflation valve, positioning balloon - 24; and,
CA 02246434 1998-08-12
W~ 97~2884~1 PCT/US96~02~i00
G. Inflation valve, expander balloon - 28.
The following dimensional inforrnation will aid in underst~n~in~ the
constl~ction of a tissue expander device.
A. Tip ~ith drain;lge eyclct(s) - 14 all~l 20:
The tip or distal end 14 an~l catheter tube or sllaft is pre~rably
between about 12-30 French, and preferably about 14-18 Frencll. The
end of the tip is preferably radiused. The lengLh of the tip, ~rom the
end of the tip to the positioning balloon is preferably about 30-40 mm.
Drainage eyelets (orifices) 20 are preferably round, circular or oval in
shape and shoul(l prefierably not exceed the width Or tlle drainage
lumen. Eyelet size should preferably not be less than 2.5 times
greater than, the cross-sectional area of the drainage lumen.
Reference: British Standard (BS) 1965 Part 1 (incorporated hereill in
its entirety by reference).
15 B. Positioning balloon - 16:
The positioning balloon is preferably loc~ted about 30-40 mm from
the end of th,e tip 14 and should not cover the drainage eyelets 20
when inFI~ d. Tlle balloon is preferably distensible and has a
r~l,ed shape whicl1 is a relatiYely symmetrieal douglmut shape
when inflated. The balloon has a preferred nominal inflation volume
of about 5-30 ml. The balloon may be fabricated from latex, silicone,
C-Flex or other distensible elastomer, pre~erably silicone and may
inelude double layers as seen in Figures 5, 6 and 7. IJninFlatr(l, the
balloon may be up to about 4 sizes French greatcr than the labeled
shaft size, but preferably no greater tllan I French. The length of the
uninfl~te~l balloon should be 1-2 Clll, preferably about 1.5 cm.
Reference: BS 1~65 Part 1 and ASTM F 623 (ineorporated herein in
their entirety ~y reterence).
- C. Expander balloon - 18;
The expander balloon 18 should preferably be loeated about one-half
~ eentimeter or less from the positioning balloon 16. The shapc of the
expander balloon 18 is preferably cylindrical with the ends configured
to enable expansion close to the external sphincter and the bladder
CA 02246434 1998-08-12
W O ~7/~8840 PCT~US96/02500
-12-
neck. See U.S. Patent 5,007,898 whicll is incorporatccl hcrcin by
reference for general guidance in this rcspect. The expander balloon
is distensible or preferably cxhibits controlled distensibility, unlike the
prior art dilathlg deviccs which are non-distensible.
The expander balloon 18 may be produced in various inflated lengths
from about 15-75 mm. Tnfl~t~ d Ai~m~ ters of expander balloons with
limited distensibility may range from about 10-30 mm (30-90 French).
The expander balloon may bc fabricated from elastomers such as C-
flex, silicone, latex or other low modulus elastomers and may bc
comprised of double layers as seen in Figures 5, 6 and 7. Balloons
with limited distensibility may bc fabricated from higher modulus
polyurethane or lower modulus elastomers in combination with
reinforcing materials. Reinforcements of this type and limited
distcnsibiliLy are taught in U.S. Patcnls 4,651,721, 4,718,410 a~
4,881,530, all of which are incor~oratcd herein by rcferencc. For
example, extensible polyurethane spandex filament may be wrapped
with a non-e~tcnsiblc polyester filament and l;lliLted into a rcin~orcing
element whicll is embcddcd in a low modulus clastomer. Longitudin~l
pleated elements of non-distensible materials may also be used in
combination with elastomeric membranes for expander balloons with
controlled extensibility.
D. Triple lumen catheter - 12:
The triple lumen catheter 12 will preferably have a round or oval
shape and range in size from about 12-30 French, prcferably about 16
French. A major lumen 36 is provided for urine drainage and is
preferably sized to yield a minim~lm flow rate of about 100 ml. pcr
minute when tested per BS 1965 Part 1 or ASTM F-623. Two minor
lumens 38 and 40 are provided for infl~ing the positioning and
expander balloons. Preferably the cross-sectional area of the minor
lumens is about .50-1.0 square mm., to afford a reasonably rapid
balloon inflation rate.
A nodule 62 (Figure 5) may be located on the sha~t 8 rnm or
thereabouts proximal from the exIl~n~r balloon. In this respect,
CA 02246434 l998-08-l2
W 097r28840
PCTAUS96~25W
-13-
reference is made to "Balloon Dilation of the t~thPt~ r", ~oseph B.
Dowd and Jo~m Smith, Urolo.~ic Clil~ic~ f Nort/~ enca, ~'olume
17, No. 3, August 1990 which is incolporated hcrein by reference.
This nodule 62 may bc usc(l by tllc pllysiciall to assurc tllat tllc
S expander balloon is not positioned in the external sphinctcr, i.c., thc
nodule may be palpated with the index finger through the rcctum.
To prevent occlusion of major lumen 36 at the balloons,
reinforcement may be incorporatcd in ~hc wall of tlle sha~t. I;or
example, a slccve havillg hi~her modulus ~han lhc cathcter sllaft walls
may be used to support the lumcn and rcsist external forccs on the
shaft. This has already been referred to in conncction witll Figure 5.
The catheter shaft or tube 12 may be fabricated rrom latex, silicone,
C-Flex, polyurc~hanc, or othcr suitablc clastomcr. Thc prcfcrrc(l
material is silicone.
15E. Urine drainage funncl - 37:
The proximal cnd of the calhcter shaft 12 tcrminatcs at thc urinc
draina,e funnel end portion 37 and thc branchecl funncls 39 and 41
connected to the minor catheter lumens 38 and 40. The urine
drainage funnel 37 is prcferably the central funnel end portion because
it connects to the major lumen 36. The funnel length is about 25-60
mm long and is preferably cylindrical, conical or a combination
thereof. An appropriate connector jOillS the drainage funnel to a urine
collection device (not shown). Thc material used for the ~unnel is
preferably the same as the catheter shaft.
2~ F. and G. Inflation funnels 39 and 41 and valves 24 and 28 ~or
positioning and e~p~n~ler balloons 16 and 18:
The branched funnels 39 and 41, preferably cylindrical,'are used to
connect the minor lumens 38 and 40 to the inflation valves 24 and 28.
Thermoplast;c m~-lic~l inflation check valves 24 and 28 are secured to
the branched funnels. The check valves have elastomeric seals a~d
may have stainless steel springs. The valves preferably have a 6%
female Luer taper per ANSI/HIMA MD 70.1 and BS3930
(incorporated herein by reference~, and are operated with a medical
_
CA 02246434 l998-08-l2
W O ~7/28840 PCT~US96/02S00
14
syringe 32 or other pump having a 6% Luer taper (valve 28 ineluding
a hub as earlier described). A thermoplastic retainer sleeve may be
iitted over the exterior surface of the funnel end portions to retain the
valves. Valves alId rc~ainers of this type are available from Bespak
Ple, of NorÇoll;, l~ngl~ The branched runnels are preferably
fabricated with the same materials as the catheter shaft.
The overall Iength of the tissue expander device is preferably about
380 mm (l~Ç~,el1ce BS 1965 part 1).
The tissue expander device may include a hydrophilic sur~ace which is
10 bonded to the catheter shaft and balloons. Considerable prior art exists on
composition and ~tt~cl ment of hydrogels ancl hydrophilic surface treatments to
hydrophobic elasLomers. This will already be known to tl1ose familiar with the
IllCdiC~ cvicc art.
T~e~llce inclwelling catheters present a patlI for in&ecLion, a
15 prophylactic antibiotic may be incolporated in the hydrophilic surface. Alterna~ively
the antibiotic may be applied by the physieian who would soak the expander in anantibio~ic solution before pl?cing it in the patient.
Following are examples of hydrogel surfaces and antibiotics which
may be impregnated into them.
2~ Hydrogel materials may be bonded to the surfaees of the balloons and
sllaft ~or greater patient comfort and reduced tissue irritation. The hydrogel may be
~ ple~ ated and packaged with antibiotic agents. Alternately the physician may
soal~ the hydrogel coated device in antibiotic prior to insertion.
_
CA 02246434 1998-08-12
W O 97~28840
PCT~US96/02500
-15- :
-
The following are examples of hydrophilic (Hydrogel) materials:
PI-Iema (Poly 2-~-Iycll oxye~hyllnetllacryla~e)
PVA (Poly Vinyl Alcollol)
PEO (Poly Elhylene Oxide)
NVP (N, Vinyl -2- Pyrrolidone)
Cellulose Ethers
Examples of Hydrophilic Copolymers are:
NVP and Polyurethane
NVP and PHema
10 Examples of Hydrophilic/Hydrophol)ic Copolymers are:
NVP and MMA (Metllyl Methacrylate)
PHema and EMA (Ethyl Methacrylate)
PHema and Hexanediol Mono Methacrylate
Copolymerization of hydro~els af~ords Llle opportunity to tailor the
properties such as water content, processing characteristics, and physical properties
in the unhydrated state. The time release characteristics for the release of antibioties
may also be tailored with eopolymerization of the hydrogel surfaee component.
The following are examples of antibiotics whieh have obtahled
aceeptanee in the treatment of urinary traet infeetions, which may be ineorporated
into a hydrophilic surfaee:
Nitrofurantoins
Quinolones
Cephalasporins.
Combinations of more than one antibiotie may prove beneficial in
eontrolling org~ni~m~ that may develop r~ci~t:lnre to exten~ed exposure to a single
antibiotie.
The expander will preferably be supplied sterile in a quadruple barrier
pael;a~e (not shown). A first mierobial barrier pael~age inside a seeond mierobial
barrler paekage would be plaeed in a shelf box whieh has a proteetive plastie shrinl~
wrap. Sterilization may be aeeomplished using gas sterilant sueh as ethylene oxide,;
radiation sueh as eleetron beam or g~mm~, steam autoelave or dry heat.
_
CA 02246434 1998-08-12
W O 97/28840
PCT/U~ 2500
-16-
TISSUli, ~XI'ANSION T'ROC~T~T)URE~
Sizing of the appropriate distensible balloon to be used in the
procedure is done ~irst. This may bc accomplisllcd as in lhe prior art by usc of a
calibration ca~llctcr whicll mcasurcs lhc (listallcc bctwccn thc blad(lcr ncck and the
external sphincLcr within thc prostatic uretllra. The physicians may thcll selcct tlle
tissue expander catheter of the invention whose distensible balloon length is closest
to the n~easurement taken. A variety of sizcs will be availablc for this sclection.
Commercially, the expander balloon will be made available in
different lengths to conform to the length ol~ the prostatic urethra. Measurin~ thc
10 distance fron1 the bladder neck to the bottom of the prostate gland has been
previous}y described by Klein in U.S. Patent 4,660,560 and Klein et al, in U.S.
Patent 5,002,558, both of which are incorporated herein by reference. The deviceof tlle present invention woulcl preferably be accompanied by such a cathcLcr tomeasure prostate leng~h with a cystoscope as part of the commercial package.
15 ~Iowever, since it is well known it need not be described herein in detail.
The selected tissue expander cathetcr is inserted into the urethra with
the aid of lubricating jelly ,or the likc making surc that thc positioning balloon and
catheter tip have passed throu~h the bladder neck and the expandcr balloon is
positioned within the proshtic urethra.
Figure 8 illustrates the placement of the tissue expander 10 including
the distal tip 14 and associated components, including the positioning balloon 16 and
the distensible tissue expander balloon 18 with respect to the bladder 54 and thc
prostate 56 through the urethra 59 of a male. Before insertion into the urethra, the
balloons are in a completely deflated state and are collapsed against the tube 12.
25 The inElation of both the positioning balloon 16 and at least the partial inflation of
the distensible tissue expander balloon 18 anchors the distal tip 14 of the cxpander
device to the bladder neck 58 at a point between the positioning balloon 16 and the
distensible tissue expander balloon 18. The positioning balloon 16 remains entirely
within the bladder 54 and the distensible tissue e~pander balloon 18 remains entirely
within the prostatic urethra 60 within prostate 56. The ~~ictenSjl~le tissue eYp~nrler
balloon 18 is then slowly inflated as desired over a period of tirne to gradually
increase the prostatic urethra to a desired size. Once the desired size is reached, the
tissue expander may remain in place for a period of time to stabilize growth.
CA 02246434 1998-08-12
WO 97/28840
PCT/lJS5.~ 5_ C
-17-
After~ards, thc balloons are de~lated by opening valves 24 al1d ~8 and the e~cpander
device 10 is then wi~hdrawn from the bladder ancl the urethra.
Generally speaking, it is antici~ated that a maintenance pressure of
~ about 2-5 psi will be adequate WiLllill Ihe distellsible l~lloon atld allui(~ alioll
S volume adequate to size the balloon witllin about 8-10 mm in diameter iniliaily with
gradual step-wise expansion to about 15-30 mm in diameter will bc ef~ective withtlle procedure Or this invention. The proceclure may e~;Lend over 5 period of days or
even weeks. It is anticipated tllat about 3 wee~;s will be effective. During this lime
it will be n( cess~ry for ~lle p~atient to wear a Ic~ bag or the li~e whicll may be
conneete(l to port 30 for colleetion of urine.
FURTHER EI~IBOOIMENTS
Up to this point the invention has been described with re~erence to a
more b~sic embodimel1t ~hereof. In that embodiment, ~he physician installs the
tissue expander and sees that patient periodically, perhaps once a day for example,
to adjust the pressure and size of the distensible balloon as desired ancl otl1er~vise
inspect the device lor prop~r posi~ioning and the liL~e.
In this basic embodiment the physician would inflate the e~pal1der
balloon 18 and adjust intraluminal pressure using a syringe with pressure gauge to
introduce sterile nuid through the check valve 28 ~tt~chrd to the proximal end of tlle
expander. The patient would return to the physician periodically during the prostate
tissue expansion period for e~cpander fluid adJustments.
However, a pump may be included witl1 the device during the
procedure and conn~ct.od long term to the di~ten~ible balloon port 26. The pump
may include a pressure regulator arrangement (as shown in Figure 9) or tlle li~e for
the physician to adjust the pressure or it may be preset to regulate a predetermined
pressure within the balloon ~as shown in I~igure 10). Such versions are now
described llerein~elow.
raticnt Pump Witll Optional Featurcs (Figurc 9)
The first mentioned further embodiment offers a patient pump 80 with
optional fea~ures wllich is similar to the basic embodiment except that pump 80
includes a means (sho-vn in Figure ~) for the physician to adjust the pressure at
which the regulating pump valve 88 opens. The physician uses a Luer adapter to
CA 02246434 1998-08-12
W O 97~8840
PCTrUS96/02500
-18-
connect a syringe 150 (see ~:igure 11) and pressure gauge 160 to thc pump. An
optional adjusting tool 100 is inscrtcd through an optiollal access port 102 andengage(l wiLh an optional pressure adjUStill<'sC~ screw 104. Tlle surgeon uscs lhe
syringc lo clc.lLc l~acl; pIcssurc On l31C ~u~ ul)illg 90 al~ alvc ~8. Thc g;-uge
at~a~hecl to the syringe will in(licate the pressure at whicll the regulating valYe 88 iS
sct. E,~;cess llui~l will vent rrom the pUlllp bulb along the opliollal fluid path 106
betweerl the acccss port 10 in thc pump bulb 82 ancl the adjustmenL tool 100.
The ~ollowing optional components (all shown in Figure 9),
distinguisll the pump as modified for lhis embocliment.
Threaded bushing - 108
The chamber housillg valvc 88 ~Iso contains thc internally threaded
bushing 108. The bushing may be metal or thermoplastic and is
bonded to the chamber. Tlle bushing thread must be large enough to
accommodate tl1e spring. For a .125" spring diameter, a ~Y8 32 UNI~
thread is used. The bushing leng~h is adcquate to housc the set screw
and to allow for advance or withdrawal of the screw to achie~e the
antici~ated pressurc range. For e.Yample witl1 a 0-10 psi range the
bushing would be approximately .38" in length.
Adjll~tmt~nt Set Serew - 104
The socket head adjustment scrc~v 10~ is fabricated from metal or
thermoplastic and has a thread compatible with the busl1ing 108. The
set screw is advanced or withdrawn to lengthen or shorten the
chamber Iength a~ailable for the compression spril1g 58c. Varying the
chamber length varies the preload of spring 85c and changes the
pressure setting of regulating valve 88. Adjustment screw 104 has
through hole 110 in it so fluid may pass through the screw during
ad~ tm~ A tllermoplastic insert (not shown) may be set in a recess
located in the threads to prevent rotation below the torque that is
available with the adjustment tool 100.
Pressure Adjustment Tool - 100
A metal or thermoplastic adjustment tool 100 in the form of a he~
shaft with a finger grip is providcd. The adjustment tool cngages
adjuslment screw 104 so that it can bc rotatcd for pressure a(ljus~ment.
CA 02246434 1998-08-12
WO 97J28840
PCTnJS96/02SOO
-19-
The en(l of ~lle tool sllaft ~vllicll cll~agcs tlle sct scrcw contains a iluid
passage 106 ~vhich tcrminates at a cross hole 1û6a on thc tool shaft.
Thc purpose o~ this ~luid chal1ncl 106 is ~o allow llui~l lo escape thc
- valve during adjustmcnt willlouL hLIViIIg tO rcmove thc tool.
Acccss Port- 102
The pump bulb contains access port 1û2, thlough which the
adJustment tool 100 is passed to engagc sct screw 104. This may bc a
simplc aperture and plug or a duckbill-type valve that is configurcd Lo
resist opening with negativc pump bulb prcssurcs. A leaf-ly~c valvc
of thc type used in inflatable m~mm~ries, Ref. U.S. Patenl 4,7~2,S26
incorporated herein by reference may also be used.
The pump and syringe both have a male ~ucr Loc~ fitting as can be
seen in Figure 11, respectiYely.
A Fcn~le Lucr a~ p~er 162 (sce ~igure 11) is provide(l to connect thc
syringe 150 and gaugc 160 to the pump in order to adiust the pressure
of regulating valve 88.
The adapter ~ay bc metal or thermoplastic. The fitting is fabricated
witl1 6% remale Lucr tapers on both en(ls to engage the syrinne and
pump Luer. Luer hubs are optional.
2U The Presct P~tient Pump (~igurc 10~
In a preset pump embodiment (Figure 10) the physician infl;ltes the
expander balloon and adjusts the pressure using the method described hereinaboYefor Ihe more basic embodiment. The syringe an~l gauge are then removcd and the
inflation clleck valYe 28 closes. With this embodiment, a patient pump 120 with
reservoir and preset pressure regulating valve is provided. Such a pump is shown in
Figure 10.
The physician fills the pump and reservoir with sterile fluid and
connects the pump to the inflation checlc valve for the expander balloon. ~ maleLuer Lock fittillg affixed to the pump engages the female Luer hub on the checlcvalve. Tlle physician squeczcs Lhe pump bulb ~nd lhc cxpan(ler intr~ nin~l
prcssure is cstablisllcd by the pump regulating valve. Tlle patient is instructed to
periodically squeeze the pump to m:~int:lin the intraluminal pressure on thc expander
balloon. The preset regulation feature of the pump pre~ents over pressurizing.
CA 02246434 1998-08-12
W 0 97t28840 PCTrUS96/02500
-20-
The preset paticnt pump is shown in I~i~ure 10, generally indicated at
120 an~l consists of an elastomeric pump bulb 82, that may clouble as a reservoir,
which is joined to a valve segment 84 cont~inillSg lwo va~ves 86 and 88. A single
tube 90 en~n:-t~s from the valve segment and terminates at a male Luer LocL; fitting
92 (not shown but similar to Figure 9). Tlle pump includes a pressure rcgulationfeature whicl1 is set at the factory.
Pump Bulb - 82:
The pump bulb 82 is preferably a molded clastomer such as latex,
silicone, polyurethane, EPDM or C-Flcx, preferably silicone. The
fluid volume may vary but is anticipate(l to be on the order of .lbout
10-20 ~nillili~ers
Valve- 86:
Valve 86 is located in the fluid path between the pump bulb 82 ancl
the tubing 90. The valve consists of an elastomeric valve seat 86a,
check ball 86b and compression spring 86c. The ball prefcrably is
about .125" in diameter and the spring is about .125" outside diameter
with a leng~ll of approximately .31". The ball S6b and spring 86c
may be fabricated from AISI 304 if sterile ~vater is used, or a cobalt,
nickel, molybdenum and chrome alloy if a saline solution is usecl.
Both metals are commercially available from several sources
domestically. Valve 86 is oriented as a spring-loaded checl~ valve, so
that when the pump bulb 82 is squeezed, fluid will flow from the
pump bulb through valve 86 and into the tubing 90. Pump valve 86
prevents fluid flow in the reverse direction from tubing 90 to the
pump bulb 82.
Valve- 88:
Valve 88 uses the same type of ball and spring as valve 86, and has a
similar valve seat 88a, ball 88b and spring 88c. This valve is oriented
so that it functions as a preset pressure regulating valve. This valve is
also located in a fluid path between the pump bulb 82 and tubing 90.
When the pump bulb is squeezed, the regulating valve 88 remains
closed and fluid is prevented from flowing from the pump bulb to the
tubing. When the pump bulb is releasecl, pressure in the tubing 90
CA 02246434 1998-08-12
W O 97/28840
Pcr~uss6~azsao
and cxpandcr balloon 18 in exccss of tlle pressurc sc~ling of the
regulating valvc, is vcntcd from thc tubing 90 through valve 88 to the
pump bulb 82.
The valve segment llousing 84 valYes 86 and 88 arc rabricatcd ~;Ol11
S an elastomer, preferably silicone. As is known in Lllc v~lvc arL, thc
springs m~y be selccted to provide prcdetcrmilled or preset rcgulation
based on thcir strength.
Pump Tubing - 90:
The pump tubing 90 colmccts the l)ump valve segment 84 to the male
Luer Locl~ fitting 92, and provides a llcxible fluid conduit so that the
pump may be remote from the proximal end of the expancler clevicc
10. The tubing is clastomcr, preferably silicone. Tlle tubing
preferably has a bore of about .031 to .062 inch, with a wall tllic~ css
equal to or greater than about 50% of thc bore. The tubing may be
molded integral with the valve segment 84 or extrudcd and
- subsequently ~onded to it.
Luer Lock -,92: (See Figure 9 for simil~r arrangcment)
A male Luer Locli 92 llaving a 6% taper is af~lXedtO the end of the
tubing 90 with a compression collar 94. The ~uer fitting ancl collar
are fabricated from either metal or thermoplastic, an~l are availablc
from several domestic sources. The male Luer Lock is sizcd per
ANSI/MIMA MD 70.1 (incorporated herein by referencc) tO engage a
female Luer taper and hub Oll the expander inflation chec~ valve 28.
MEASURING PROCEDURE
An anesthetic sterile lubricating jelly is inserted into the urethra a rew
minntes prior to measuring. A cystoscope sheath with a minimllm
bore of 11 French is inserted into the urethra up to the external
sphincter. The measuring catheter is passed through the cystoscope
hridge sideaml and wor}iing chamlel of the cystoscope sheatll and into
the bladder. Tlle l~ositioning balloon is ~hen inflatcd with stcrile fluid,
to its recommended volume, using a syringe engaged to the check
valve. The syringe is then removcd which closes the check valve and
m~tin~in~ fluid in the positioning balloon. A gentle traction is appliecl
CA 02246434 1998-08-12
WO 97/28840
PCT~US96/02500
-22-
to thc measuril1~ calllclcr to draw ~IIC ~ositioning balloon against the
bladder neck. The cystoscope is lllell used to mcasurc thc distallce to
Llle extcrnal sphincter. Wllen mcasurclllent is complcted, lhc
positioning balloon is defla~ed using a syringe engaged to the check
valve. The measuring catlleter is withclrawn form thc cystoscope and
the cystoscope is withdrawn form Lhe urethra.
PI~OSTATE EXPANSION PROCED~JRE WITH PATIENT PUMP
After the prostaLic ure~hra is measured to determinc thc distance from
~he bladder neck to the external sphinctcr, an c~cp;mdcr 10 of
appropriate size is sclected. An anesthetic lubricating jelly is insertcd
hlto the ureLhra. The cxpander is coatcd with jelly and inserted
hrougll thc urethra ancl into the bladdcr. A syringe filled with stcrilc
fluid is connec~ed to the inflation check valve 24 for thc posi~ioning
~alloon 16. The balloon is inflated to tlle recommcnded volullle and
the syrin~e is discngaged to close chcck valvc 24. A gentlc traction is
applied Lo ~lle expander cathe~cr shaft to urge the positioning balloon
against the b!addcr ncc~. With a palpatillg index fingcr in thc rcctum,
~he pllysician can dctcrmine if thc nodulc 62 is at the apex of the
prostate, wllicll indicates corrcct sizing of thc expander. While
Ill~itlt~lillillg gentle traction on thc positioning balloon, the expander
balloon 18 is inflatcd. To fill the cxpandcr thc pllysician uscs a
syringe with sterile fluid and engages it to the Luer fitting on the
check valve 28 for thc expander balloon. The syringe is cquipped
with a pressure gauge to indicatc thc intr~ min:ll pressure of the
expander balloon. Fluid sllould bc introduccd into thc expander and
withdrawn several times, with the extcrnal sphincter positioned
superior to the prostate, to evacuate any air. The physician then
inflates the cxpandcr to recommended prcssurc; chcc~s the fit of the
expander after inflation by palpating the locating nodule 62; and
disengages thc syringe wllicl~ closcs thc expandcr balloon chccli valvc
28.
When the physician uscs a paticnt pump (~igure 10~, it is fillccl ~vith
sterile fluid al1(1 connccted to tlle cxpander balloon check valve 28.
CA 02246434 1998-08-12
WO 97~28840
PCT~US96~25U0
-23-
An a.ppropriate Lucs Locl~ fitting on the pump tubc securcs the pump
to check valve 28. Tlle pump bulb is s4ueezcd and t}le expandcr is
inflated to the predetermined pressure.
Alternatively, if the cmbodimcnt (pump Figure 9) wilh optiona.l
adjustable regulator valve is uscd, the physician uses a Luer adapter to
attach the syringc and gauge to tlle pump. The optional adjustment
tool 100 is tl~en insertcd throu~ll tlle pump bulb and into the
adjustment screw 104 on the regulating pump valve 88. The
physician Lllcn applics iluicl ~ressurc with Lhe syringe and ol3scrves ~he
pressure required to open tlle regulating valve 88. The reguiating
pressure is ~hen adjustcd by turning tllc adjustment scrcw 104 to cithcr
increase or decrease the pressure Or the rcgulating v~lve ~8. The
adjustment tool is withdrawn and tlle pump is f~llcd and Llle syringe
and Luer ad.apter arc disconneeted. The pump is then secured to
checl~ valve 28 using an appropriate Luer Lock fitting wllich may be
provided on tl1e pump tubing. The physician squeezes the pump bulb
and the exp~nder is inflated to the physician determined pressure.
The patient is instructed to periodically squeeze tlle pump bulb to
n~in~in the desired intr;~ min~l pressure on the expander balloon.
Periodic squeezing of the pump bulb will replenish fluid lost to
osmosis, restore lluid pressure whicll may have been depleted due to
~issue expansion, or physiologically induccd pressure spikcs wllich
may have caused regulating valve ~8 to activate.
Optimum expander balloon intraluminal pressure will vary. ~Iowever,
it is anticipated that the pressure rangre will be 1-1/2 to 10 psi.
ASTM standard for soft tissue expanders requires that the injection
site septums not leak wllen testecl with 120 mm Hg ~2.32 psi).
Previous testing of prior art tissue expander injection sites resulted in
- Ieakage around 5 psi, which would indicate tissue expansion occurs
below 5 psi. ~ ximllm urethral pressure from urinc flow is reported
to be 100 cm H~0 whic,h is 1.42 psi.
Various modifieations can be made to the present invention witllout
departing from tlle apparent scope l.ereof.
