CA1283504C - Implantable fabric pouch for mammary prothesis - Google Patents
Implantable fabric pouch for mammary prothesisInfo
- Publication number
- CA1283504C CA1283504C CA000515208A CA515208A CA1283504C CA 1283504 C CA1283504 C CA 1283504C CA 000515208 A CA000515208 A CA 000515208A CA 515208 A CA515208 A CA 515208A CA 1283504 C CA1283504 C CA 1283504C
- Authority
- CA
- Canada
- Prior art keywords
- pouch
- axis
- accordance
- parallel
- along
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/12—Mammary prostheses and implants
Landscapes
- Health & Medical Sciences (AREA)
- Cardiology (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Transplantation (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Vascular Medicine (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Prostheses (AREA)
Abstract
ABSTRACT
The present invention discloses a pouch to contain a mammary implant formed from a net-like material fabricated from a bio-compatible non-biodegradable yarn; the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inextensible in the vertical direction as compared with at least one axis non-parallel thereto.
The present invention discloses a pouch to contain a mammary implant formed from a net-like material fabricated from a bio-compatible non-biodegradable yarn; the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inextensible in the vertical direction as compared with at least one axis non-parallel thereto.
Description
3~;~4 IMPLANTABLE FABRIC POUC~I FOR MAMMARY PRaIHESIS
lhe present invention relates to mammary protheseS ard in particu]ar to an implantable fabric pouch for encapsulating such mammary protheses.
For a n~ber of years surgeons have augmented and changed the shape of womens breasts by the introduction of mammary protheses_mt4 the breast area. Typically these mammary prothesés have comprised a closed silicone sac filled with gel or saline solution.
Most patients experience satisfactory mammary augmentation immediately following the implantation procedure wqth the breasts simulating natural breasts in contour, appearance, feel and dynamics~ However during a relatively short period after the implantation procedure, usually about six months, many patients experience a contracture of the tissue surrounding the mammary FrothPsis causing it to assume a spherical shape and other unnatural attributes. In addition to the upper surface of the breast tending to display unnatural convexity the breast may also become tight and not freely moveable.
This problem wqth mammary prot~eses has been appreciated for some years and for example U.S. patent 3934274 seeks to overcome the problem by use of a double ~IEn prothesis having an outer and an inner chamber,the outer chamber of which may be evacuated once tissue contracture is experienced thereby relie~ing the forces exerted by the tissue and alleviating the .../3 ' - ~ :
~2~35~3~
unnatural tendency of the prothesis to adopt spherical shape.
To date however a satisfactory longterm solution to the problem of tissue contracture about a mammary implant has not been found and this may perhaps be due to the lack of u~derstanding of the reasons for such tissue contracture.
It is an object of the present invention to reduce the incidence of tissue contracture around a mammary implant.
Accordingly the present invention disclosesan irplantab3e Pl~h to contain a mammary ~prothesis formed from a net-like material fabricated from a bio-compatible non-biodegradable yarn; the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inextensible alon~ the cephalic-caudal axis as ~ compared with at least one axis non-Parallel thereto.
The present invention additionally discloses a method of performing a mammary implant operation comprised of the steps of:
a) Selecting a pouch in accordance with the present invention having a diameter of between 0 and 40 per cent greater than the equilibrium diameter of the pro~es-,s which it is to contain;
b) Placing the F~t'nesis within the pouch;
c) Locating the pouch and pr~t~esis in the breast such that the antericr layer of the pouch is relatively inexte:-sible alon~ the cephalic-caudal axis.
.../4 ....
, . . . - . . .
, ' ' - ', ~ , ~2E335~fl~
One embodiment of the present invention will now be described wqth reference to the acco~panying drawqngs in which:
Figure 1 is a side elevation of a breast with a mammary Fro ~ sis in a pouch in accordance with the present invention in vertical section;
Figure 2 is a side elevation in vertical section along the diameter of a mammary FXo ~ sis and pouch in accordance with the present invention in an equilibrium position;
Figure 3 is a side elevation in vertical section along the diameter of a mammary Fro~E~s and pouch in accordance with the present invention in a fiatten~d.non-equilibrium state;
Fi.gure 4 is an anteriorview of a mammary Fxo ~ sis inside ~ a pouch in accordance with the present invention as ît would appear with the patient standing;
Figure 5 is a perspect;ve view of a pouch in accordance : with the present invention which has been lifted to show part of the posteriorlayer~
Figure 1 depicts a pouch l in accordance with the present : ~0 inventi~n encapsulating a silicone mammary F~o~E~is 2 filled ~qth gel 3. Breast tissue 4 is shown around the anteri.orsurface of ~he pouch. It will be noted that the mammary ~rnthP~i.s is a loose fit inside the pouch in order that the Fro~Y~is may adopt a natural teardrop shape there being excess space inside the pouch at 5.
`
. ' :.
. .
. . . .
," ~ . .- .
~2~350A
It has been found desirable that the pouch be slightly greater in diameter than theiFr~th~sis and in the example depicted at figure 2 the pouch diameter exceeds the diameter of the Fro~sis in its equilibrium position by approximately 20 per cent.
If the Fro~is of figure 2 where 10 centimetres in diameter there would consequently ~e a clearance of approximately one centimetre at areas 6 Hni7.
This excess space inside the pouch allows the silicone prothesis to spread or expand or balloon to a limited extent when deformed as depicted in figure 3 until is occupies the entire lumen of the pouch. This ensures that the breast will not feel overly tight and will maintain soft and flexible to the touch.
- Figures 4 and 5 de*ict the orientation of the yarns comprising the pouch with respect to the mammary pro~Y~is.
As may best be viewed from figure 4 the fabric of the pouch has st~s 8 running along the cephalic-caudal axis and according to the present invention these strands are relatively inextensible. The mammary implarlt 2 may be seen within the pouch, the upper extremity of ~he Fro~sis being the semi-circle 9. This view indicates the orientation of the Fnnth~sis with respect to the pouch with the patient in a stahding position.The pLnt~eSi~s is naturally maintained in the lower part o the pouch under the influence of gravity.
.../6 .
' ' 5 ,' ,' ' . ' ' " ' ' ' . ' ' ' ' '' ' ' ' ' . '' ' ' 35~
'rhe tenm inextensible where used throughout this specification refers to the extensibility of the fabric of a pouch along a certain axis but calculated after the pouch has been implanted in the body for a period of time adequate to achieve substantial ingrowth of body tissue through the fabric.
It is necessaryto define the extensiblity of the fabric in this manner for the following reason.
The embo~iments depicted herein with reference to figures 4 and 5 depict inextensible yarn running parallel to the axes along which the fabric of the pouch is intended to be inextensible.
- Consequently the extensibility of the fabric in this example corresponds exactly to the extensibility of the yarn from which the fabric is manufactured. This relationship between the extensibility of the fabric and the yarn along these axes is of course the same both before and after the pouch is implanted in a patient.
Pouches have however been constT~cted from fabrics in which the yarn does not run parallei to the cephalic-caudal axis or other axes intended to carry stress but such pouches nevertheless achieve inextensibility along the said axes once implanted and invaded by body tissue. For example the fa~ric can be a tulle net which is supplied pre-stressed in one direction.
This will produce a diamond pattern between the fabric yarns with the long axis of the diamonds aligned in the direction of stress.
Aft~r implantation in the body and as the diamonds fill with tissue the fabric will stabilise and will be far less extensible along the ...~7 ;-' ', . ' ~ ' ~Z~33~)4 axis corresponding to the long axes of the diamond pattern in ~he abric than along the short axes of the diamonds. The fabric is pre-stressed in the sense that the cross over points for the fabric yarns are fixed such that diamond like pattern in the fabric is of a configuration which gives the desired resistance to distensîon along certain axes.
It has been found that if the pouch is relatively inextensible on the anterior side along the cephalic-caudal axis that contracture of the tissue surrounding the implant is reduced hence preventing the prothesis adopting a spherical unnatural shapeO Ihe following theory is advanced as the reason why a pouch in accordance with the present invention prevents such undesirable contracture although it should be understood that the invention is not restricted to such theory.
~le applicant's investiga~ions indicate that the collagen bundles fonmingtheEibrous tissue capsules which cause tightening around breast protheses develop in response to stress within the tissue. In such casesthe preclominant forces on the tissue adjacent to the anterior side of the prothesis are along the cephalic-caudal axis and are caused principally by the influence of gravity on the prothesis with the patient in the standing position. There may also be oblique stresses through tissue on the posterior side o the breast prothesis due to thé
influence of gravity on the prothesis plus the additional influence of the transverse pull of the pectoral muscles. The applicant's mvestigations furthermore indicate that fibrous tissue is not amorphous and featureless but has a definable structure~ In the case of a fibrous tissue capsule surrounding a conventional breast prothesis the predominarlt feat.ure of the strllcture is ../8 ' ~ ' " :', ' ' ~ ' ''' .
~ 33~;04 collagen b~mdles running parallel to the lines of stress. These collagen bundles tend to act as ligaments taking up slack and hence causing undesirable contracture about a mamnary implant.
It has previously been thought amongst surgeons that fabrics which allow fibr~,-cellular ingrowth also cause increased fibrous tissue formation which would tend to cause undesirable contracture in the case of a mammary Fnot~esis. Contrary to this belief the applicant believes that the introduction of a fabric which gives support by beinginextensible in a direction parallel to the predominant lines of stress within the tissue will tend to reduce the forrnation of fibrous bundles in such direction in response to such stress. Indeed if the fabric is relatively extensible in a direction transverse to the predominant lines of stress then the relative lack of support in such dirèction may cause the body tissue to form fibrous bundles along such transverse direction.
The combined effect of such extensible and relatively ine~tensible feat ~ s of a fabric forming a pouch in accordance with the present invention encourage the formation of body tissue more akin to the natural denmis rather than the uni-directional tendon like collagen bundles which the applicant believes are responsible for undesirable capsule contracture about the implant.
Turning now to figure 4 it rnay be seen that in addition to the cephalic~xl~l axis inextensible yarn cornprising the fabric there are additionally oblique yarns 10 within the fabric which may be relatively extensible. It has been found that a tulle of poly-ester yarn (the yarn having a diameter between .01 and .5 ; mîllimetres) is appropriate. The ideal order of magnitude for the diameter of th openings 11 in the fabric is between .../~
. ' ~ ' .................... ' ' ' .
: . :, . .
~Z~35~L
one and two millimetres s~lch fabric being not unlike mosquito netting or bridal veil material although it is considered that openings in ~he order of .001 millimetres to 5 millimetres would still give advantageous results.
In the embodiment above described polyester yarn of four strancls has been considered appropriate in order to achieve the desired fle~ability although if infection occurs after implantation it may be ~.ore di~ficult to rid such multifilament(as opposed to monofilament) yarn of the infection. Nylon or '~oly~x~ylene may also , 10 be useful,even in monofilament form.
; It is envisaged that the yarn should be non-biodegradable or at least longterm biodegradable and the term "non-biodegradable"
- where used herein should be contemplated to mean non-biodegradable ' 'within'twelve''months.~'At''present'however it'is'consider'ed that'' '~ '~~'' `' ideally the material utilised should be non-biodegradable for five years or more.
Figure 5 shows the o~n~inn of the yarn comprising the pouch material on the posteriorside and it will be noted that I there are strands of yarn l2 running in an oblique direction.
`' ¦ 20 These are intended to be inextensible yarns aligned parallel I to the stresses,caused by the pectoral muscles. The strength of the pectoral muscles may vary from patient to patient and consequently a surgeon may wish to remove tissue and observe fibre orientation in order that a pouch with inextensible ' ' J o./10 . " , .
- . , . ~ . ~
.
- . , -. ' ,' s~
properties in the correct direction may be chosen. In any event a pouch should always be selected to such that it is relatively in-extensible parallel to the lines of stress along the tissue of a particular patient.
Figure 5 further depicts openin~ 13 to facilitate the insertion of the mammary prothesis.
It may be appreciated therefore that a pouch in accordance with the present invention, once invaded by tissue will help to impart support to t~e fib~s tiss~e along ~e maJor anterior cephalic-caudal stress lines and furthermore provides a template to encourage fcrraticn of a collagen network rather than collagen arranged in parallel bundles akin to aponeuroticl~nents which tend to shorten and - take up slack.
The term"equilibrium diameter"of a maTmary implant as used herein shall mean the diameter of the implant when placed in such a position as it would adopt with t'ne patient lying on her back. In the case of a double lumen mammary prothesis the diameter is that which the implant is intended to adopt after rupture ot the outer compartment.
. .
,~ .
: ~, ., . :
. .
~, . - : :
.
lhe present invention relates to mammary protheseS ard in particu]ar to an implantable fabric pouch for encapsulating such mammary protheses.
For a n~ber of years surgeons have augmented and changed the shape of womens breasts by the introduction of mammary protheses_mt4 the breast area. Typically these mammary prothesés have comprised a closed silicone sac filled with gel or saline solution.
Most patients experience satisfactory mammary augmentation immediately following the implantation procedure wqth the breasts simulating natural breasts in contour, appearance, feel and dynamics~ However during a relatively short period after the implantation procedure, usually about six months, many patients experience a contracture of the tissue surrounding the mammary FrothPsis causing it to assume a spherical shape and other unnatural attributes. In addition to the upper surface of the breast tending to display unnatural convexity the breast may also become tight and not freely moveable.
This problem wqth mammary prot~eses has been appreciated for some years and for example U.S. patent 3934274 seeks to overcome the problem by use of a double ~IEn prothesis having an outer and an inner chamber,the outer chamber of which may be evacuated once tissue contracture is experienced thereby relie~ing the forces exerted by the tissue and alleviating the .../3 ' - ~ :
~2~35~3~
unnatural tendency of the prothesis to adopt spherical shape.
To date however a satisfactory longterm solution to the problem of tissue contracture about a mammary implant has not been found and this may perhaps be due to the lack of u~derstanding of the reasons for such tissue contracture.
It is an object of the present invention to reduce the incidence of tissue contracture around a mammary implant.
Accordingly the present invention disclosesan irplantab3e Pl~h to contain a mammary ~prothesis formed from a net-like material fabricated from a bio-compatible non-biodegradable yarn; the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inextensible alon~ the cephalic-caudal axis as ~ compared with at least one axis non-Parallel thereto.
The present invention additionally discloses a method of performing a mammary implant operation comprised of the steps of:
a) Selecting a pouch in accordance with the present invention having a diameter of between 0 and 40 per cent greater than the equilibrium diameter of the pro~es-,s which it is to contain;
b) Placing the F~t'nesis within the pouch;
c) Locating the pouch and pr~t~esis in the breast such that the antericr layer of the pouch is relatively inexte:-sible alon~ the cephalic-caudal axis.
.../4 ....
, . . . - . . .
, ' ' - ', ~ , ~2E335~fl~
One embodiment of the present invention will now be described wqth reference to the acco~panying drawqngs in which:
Figure 1 is a side elevation of a breast with a mammary Fro ~ sis in a pouch in accordance with the present invention in vertical section;
Figure 2 is a side elevation in vertical section along the diameter of a mammary FXo ~ sis and pouch in accordance with the present invention in an equilibrium position;
Figure 3 is a side elevation in vertical section along the diameter of a mammary Fro~E~s and pouch in accordance with the present invention in a fiatten~d.non-equilibrium state;
Fi.gure 4 is an anteriorview of a mammary Fxo ~ sis inside ~ a pouch in accordance with the present invention as ît would appear with the patient standing;
Figure 5 is a perspect;ve view of a pouch in accordance : with the present invention which has been lifted to show part of the posteriorlayer~
Figure 1 depicts a pouch l in accordance with the present : ~0 inventi~n encapsulating a silicone mammary F~o~E~is 2 filled ~qth gel 3. Breast tissue 4 is shown around the anteri.orsurface of ~he pouch. It will be noted that the mammary ~rnthP~i.s is a loose fit inside the pouch in order that the Fro~Y~is may adopt a natural teardrop shape there being excess space inside the pouch at 5.
`
. ' :.
. .
. . . .
," ~ . .- .
~2~350A
It has been found desirable that the pouch be slightly greater in diameter than theiFr~th~sis and in the example depicted at figure 2 the pouch diameter exceeds the diameter of the Fro~sis in its equilibrium position by approximately 20 per cent.
If the Fro~is of figure 2 where 10 centimetres in diameter there would consequently ~e a clearance of approximately one centimetre at areas 6 Hni7.
This excess space inside the pouch allows the silicone prothesis to spread or expand or balloon to a limited extent when deformed as depicted in figure 3 until is occupies the entire lumen of the pouch. This ensures that the breast will not feel overly tight and will maintain soft and flexible to the touch.
- Figures 4 and 5 de*ict the orientation of the yarns comprising the pouch with respect to the mammary pro~Y~is.
As may best be viewed from figure 4 the fabric of the pouch has st~s 8 running along the cephalic-caudal axis and according to the present invention these strands are relatively inextensible. The mammary implarlt 2 may be seen within the pouch, the upper extremity of ~he Fro~sis being the semi-circle 9. This view indicates the orientation of the Fnnth~sis with respect to the pouch with the patient in a stahding position.The pLnt~eSi~s is naturally maintained in the lower part o the pouch under the influence of gravity.
.../6 .
' ' 5 ,' ,' ' . ' ' " ' ' ' . ' ' ' ' '' ' ' ' ' . '' ' ' 35~
'rhe tenm inextensible where used throughout this specification refers to the extensibility of the fabric of a pouch along a certain axis but calculated after the pouch has been implanted in the body for a period of time adequate to achieve substantial ingrowth of body tissue through the fabric.
It is necessaryto define the extensiblity of the fabric in this manner for the following reason.
The embo~iments depicted herein with reference to figures 4 and 5 depict inextensible yarn running parallel to the axes along which the fabric of the pouch is intended to be inextensible.
- Consequently the extensibility of the fabric in this example corresponds exactly to the extensibility of the yarn from which the fabric is manufactured. This relationship between the extensibility of the fabric and the yarn along these axes is of course the same both before and after the pouch is implanted in a patient.
Pouches have however been constT~cted from fabrics in which the yarn does not run parallei to the cephalic-caudal axis or other axes intended to carry stress but such pouches nevertheless achieve inextensibility along the said axes once implanted and invaded by body tissue. For example the fa~ric can be a tulle net which is supplied pre-stressed in one direction.
This will produce a diamond pattern between the fabric yarns with the long axis of the diamonds aligned in the direction of stress.
Aft~r implantation in the body and as the diamonds fill with tissue the fabric will stabilise and will be far less extensible along the ...~7 ;-' ', . ' ~ ' ~Z~33~)4 axis corresponding to the long axes of the diamond pattern in ~he abric than along the short axes of the diamonds. The fabric is pre-stressed in the sense that the cross over points for the fabric yarns are fixed such that diamond like pattern in the fabric is of a configuration which gives the desired resistance to distensîon along certain axes.
It has been found that if the pouch is relatively inextensible on the anterior side along the cephalic-caudal axis that contracture of the tissue surrounding the implant is reduced hence preventing the prothesis adopting a spherical unnatural shapeO Ihe following theory is advanced as the reason why a pouch in accordance with the present invention prevents such undesirable contracture although it should be understood that the invention is not restricted to such theory.
~le applicant's investiga~ions indicate that the collagen bundles fonmingtheEibrous tissue capsules which cause tightening around breast protheses develop in response to stress within the tissue. In such casesthe preclominant forces on the tissue adjacent to the anterior side of the prothesis are along the cephalic-caudal axis and are caused principally by the influence of gravity on the prothesis with the patient in the standing position. There may also be oblique stresses through tissue on the posterior side o the breast prothesis due to thé
influence of gravity on the prothesis plus the additional influence of the transverse pull of the pectoral muscles. The applicant's mvestigations furthermore indicate that fibrous tissue is not amorphous and featureless but has a definable structure~ In the case of a fibrous tissue capsule surrounding a conventional breast prothesis the predominarlt feat.ure of the strllcture is ../8 ' ~ ' " :', ' ' ~ ' ''' .
~ 33~;04 collagen b~mdles running parallel to the lines of stress. These collagen bundles tend to act as ligaments taking up slack and hence causing undesirable contracture about a mamnary implant.
It has previously been thought amongst surgeons that fabrics which allow fibr~,-cellular ingrowth also cause increased fibrous tissue formation which would tend to cause undesirable contracture in the case of a mammary Fnot~esis. Contrary to this belief the applicant believes that the introduction of a fabric which gives support by beinginextensible in a direction parallel to the predominant lines of stress within the tissue will tend to reduce the forrnation of fibrous bundles in such direction in response to such stress. Indeed if the fabric is relatively extensible in a direction transverse to the predominant lines of stress then the relative lack of support in such dirèction may cause the body tissue to form fibrous bundles along such transverse direction.
The combined effect of such extensible and relatively ine~tensible feat ~ s of a fabric forming a pouch in accordance with the present invention encourage the formation of body tissue more akin to the natural denmis rather than the uni-directional tendon like collagen bundles which the applicant believes are responsible for undesirable capsule contracture about the implant.
Turning now to figure 4 it rnay be seen that in addition to the cephalic~xl~l axis inextensible yarn cornprising the fabric there are additionally oblique yarns 10 within the fabric which may be relatively extensible. It has been found that a tulle of poly-ester yarn (the yarn having a diameter between .01 and .5 ; mîllimetres) is appropriate. The ideal order of magnitude for the diameter of th openings 11 in the fabric is between .../~
. ' ~ ' .................... ' ' ' .
: . :, . .
~Z~35~L
one and two millimetres s~lch fabric being not unlike mosquito netting or bridal veil material although it is considered that openings in ~he order of .001 millimetres to 5 millimetres would still give advantageous results.
In the embodiment above described polyester yarn of four strancls has been considered appropriate in order to achieve the desired fle~ability although if infection occurs after implantation it may be ~.ore di~ficult to rid such multifilament(as opposed to monofilament) yarn of the infection. Nylon or '~oly~x~ylene may also , 10 be useful,even in monofilament form.
; It is envisaged that the yarn should be non-biodegradable or at least longterm biodegradable and the term "non-biodegradable"
- where used herein should be contemplated to mean non-biodegradable ' 'within'twelve''months.~'At''present'however it'is'consider'ed that'' '~ '~~'' `' ideally the material utilised should be non-biodegradable for five years or more.
Figure 5 shows the o~n~inn of the yarn comprising the pouch material on the posteriorside and it will be noted that I there are strands of yarn l2 running in an oblique direction.
`' ¦ 20 These are intended to be inextensible yarns aligned parallel I to the stresses,caused by the pectoral muscles. The strength of the pectoral muscles may vary from patient to patient and consequently a surgeon may wish to remove tissue and observe fibre orientation in order that a pouch with inextensible ' ' J o./10 . " , .
- . , . ~ . ~
.
- . , -. ' ,' s~
properties in the correct direction may be chosen. In any event a pouch should always be selected to such that it is relatively in-extensible parallel to the lines of stress along the tissue of a particular patient.
Figure 5 further depicts openin~ 13 to facilitate the insertion of the mammary prothesis.
It may be appreciated therefore that a pouch in accordance with the present invention, once invaded by tissue will help to impart support to t~e fib~s tiss~e along ~e maJor anterior cephalic-caudal stress lines and furthermore provides a template to encourage fcrraticn of a collagen network rather than collagen arranged in parallel bundles akin to aponeuroticl~nents which tend to shorten and - take up slack.
The term"equilibrium diameter"of a maTmary implant as used herein shall mean the diameter of the implant when placed in such a position as it would adopt with t'ne patient lying on her back. In the case of a double lumen mammary prothesis the diameter is that which the implant is intended to adopt after rupture ot the outer compartment.
. .
,~ .
: ~, ., . :
. .
~, . - : :
.
Claims (10)
1. An implantable pouch to contain a mammary pro-thesis formed from a net-like material fabricated from a bio-compatible non-biodegradable yarn; the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inextensible along the cephalic-caudal axis as compared with at least one axis non-parallel thereto.
2. An implantable pouch to contain a mammary prothesis formed from a net-like material fabricated from a bio-compatible polymeric non-biodegradable yarn;
the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inex-tensible along the cephalic-caudal axis as compared with at least one axis non-parallel thereto.
the pouch being so constructed that the surface intended to form the anterior layer in use is relatively inex-tensible along the cephalic-caudal axis as compared with at least one axis non-parallel thereto.
3. A pouch in accordance with claims 1 or 2, wherein the pouch material is tulle fabricated from polyester monofilament yarn of between .001 and .5 millimetres diameter the tulle having openings between .001 and 5 millimetres diameter; the tulle being pre-stressed before implantation so as to produce an elongated diamond pattern between the yarns comprising the material with the long axes of the diamond being parallel to the axis in which the material is intended to be relatively inextensible.
4. A pouch in accordance with claim 1, wherein the material of the pouch is additionally relatively inextensible on its posterior side along an oblique axis parallel to the lines of stress traditionally present on the posterior side of a breast due to the combined influence of the pectoral muscles and gravi-tational stresses.
5. A pouch in accordance with claim 2, wherein the material of the pouch is additionally relatively inextensible on its posterior side along an oblique axis parallel to the lines of stress traditionally present on the posterior side of a breast due to the combined influence of the pectoral muscles and gravi-tational stresses.
6. A pouch in accordance with claim 1 wherein the extensibillty of the relatively inextensible axis of the pouch is no greater than 5 per cent from its equilibrium position.
7. A pouch in accordance with claim 1 wherein the relative inextensibility along one axis of the material of the pouch arises from the inclusion of layers of yarn parallel to such axis which yarn itself is relatively inextensible.
8. A pouch in accordance with claim 1 wherein the relative inextensibility along one axis arises from the manner in which the yarn is formed into the fabric rather than inherent characteristics of the yarn itself.
9. A pouch in accordance with claims 1 or 2, wherein the pouch material is relatively extensible along all axes non-parallel to those specified as relatively inextensible.
10. A pouch in accordance with claims 4 or 5, wherein the pouch material is relatively extensible along all axes non-parallel to those specified as relatively inextensible.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000515208A CA1283504C (en) | 1986-08-01 | 1986-08-01 | Implantable fabric pouch for mammary prothesis |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000515208A CA1283504C (en) | 1986-08-01 | 1986-08-01 | Implantable fabric pouch for mammary prothesis |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1283504C true CA1283504C (en) | 1991-04-30 |
Family
ID=4133670
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000515208A Expired - Lifetime CA1283504C (en) | 1986-08-01 | 1986-08-01 | Implantable fabric pouch for mammary prothesis |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1283504C (en) |
-
1986
- 1986-08-01 CA CA000515208A patent/CA1283504C/en not_active Expired - Lifetime
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