P-URE foam covered implants

Why choose P-URE foam covered implants

What follows is a patient-friendly version of the chapter from ‘Biomaterials in Plastic Surgery: Breast Implants’, by Dr Daniel Fleming.
Woodhead Publishing, Cambridge 

If you like a copy of the technical chapter please contact Dr Daniel Fleming’s offices via the enquiry form.

Introduction

Implants can have different surfaces.

Almost all surgeons now recommend implants filled with cohesive silicone gel. This “Turkish Delight” consistency minimises leakage if an implant ruptures and gives a superior feel to saline, water-filled implants. However there are different opinions about which surface is best and this can be confusing for women choosing implants. It does not have to be confusing however as, despite the differing opinions, there is only one set of facts which is supported by the evidence.

Originally, implants had a smooth surface like a plastic bag. Today the surface can be smooth, or slightly textured rather like velvet, more roughly textured like a towel dried in the sun, or covered with a layer of polyurethane foam.  As we will see, it has now been shown there is no difference in capsular contracture (hardening) rates between smooth and textured implants. However, there is a dramatic reduction in the commonest complication of breast implant surgery with the polyurethane foam covered implants.

The first P-URE foam covered silicone gel breast implants were used in 1968, only 4 years after the original, smooth surfaced breast implants were introduced.  The long-term evidence has consistently shown that P-URE foam implants dramatically reduce the complication of capsular contracture compared with both smooth and textured implants. Surgeons who use these implants have also found they reduce the incidence of displacement and rotation compared with implants with other surfaces, allowing them to use teardrop (anatomical) implants without the fear of early or late rotation associated with textured teardrop implants.

It is often not realised that textured implants were developed in 1984, some 16 years after P-URE foam. Texturing was an attempt to reproduce the benefits of the foam. If you look up the patent applications for textured implants, including Allergan’s Biocell texturing, they all start by stating the patent applied for is for a process of texturing the surface of silicone implants ‘to simulate an open cell foam to reduce capsular contracture’, or words to that effect. As we shall see, texturing implants does not reduce capsular contracture; only the P-URE foam covering can do this. P-URE foam covered silicone gel implants are made in Germany by Polytech and in Brazil by Silimed and have been approved for breast augmentation and reconstruction by the Australian Therapeutic Goods Administration, the Government’s regulatory agency.

Capsular contracture is by far the commonest complication of breast augmentation and the commonest reason for re-operation. Capsular contracture occurs when the membrane that grows around every implant contracts, compressing it rather like shrink-wrap. The implant hardens and changes shape. It looks bad, is uncomfortable and can even be painful. The only treatment that works is further surgery which is more complicated, less predictable and more risky than initial augmentation. So it is very important to minimise your risks of developing contracture. Although having an infection or bleeding after the surgery increases the risk, there is no one cause of capsular contracture and in most patients, no cause can be identified.

How common is it? If smooth or textured implants are used, nearly one in 5 patients will develop capsular contracture by 10 years after their augmentation – see evidence from the US regulator the FDA below.  Amazingly, some surgeons do not feel contracture is much of a problem.  The facts show they are wrong and one of the reasons for this is the way in which doctors diagnose and classify capsular contracture. As we shall see, the system used is very subjective and causes the problem of “observer bias”:

The Baker classification is universally used to report contracture rates (see table below), with only grades 3 and 4 being considered contractures. So a grade 2 does not count in the percentages and a grade 3 does. Because contracture is a gradual, progressive condition, all grade 3 capsules were once a grade 2. It is necessarily a subjective judgment made by the examiner in each patient, whether a capsule has reached the criteria of grade 3 (a bit firmer than a grade 2 and with some change in shape) and is therefore reported as a contracture, or if the patient is still a grade 2 and therefore contracture-free. The implications for observer bias, especially when assessing one’s own patients, are obvious.Add to this the fact that contractures increase over time and many studies have a follow-up of only a few years, it is then not surprising that there is such a diverse range of reported incidences for textured and smooth breast implants.

When I talk to surgeons at scientific meetings around the world, many of them tell me that they don’t see much capsular contracture in their patients but they ‘see a lot from other doctors’. Also they say that the commonest reason they perform repeat surgery is capsular contracture. They often fail to make the connection that ‘other doctors’ may well be seeing their contractures! All of the evidence shows that when independent assessments of a surgeon’s contracture rate are made they are always much higher than the surgeon had thought.

There is also an often-stated, though misplaced, belief that textured implants offer less risk of contracture than smooth implants. This is based on an analysis of a number of studies which had looked at the problem. This showed very variable results but concluded that textured were slightly better but only for placement in front of the muscle and not for behind the muscle. Of course, this analysis was only as good as the original papers that were analysed and it turned out the original papers were not reliable. So there has been a desperate need for a properly conducted study to find out what the true rate of contracture is and whether there is any difference between smooth and textured surfaced implants and now we have exactly that.

Professor Scott Spear, one of the world authorities on breast augmentation, commenting in the Plastic and Reconstructive Surgery Journal, has observed: ‘The information that Plastic surgeons will be most interested in would be that regarding single-lumen textured and smooth silicone gel implants. The very best data regarding those devices are available from the core clinical studies that were submitted to the Food and Drug Administration over the last year as part of the Premarket Approval process both by Inamed (now Allergan) and Mentor.’ Commenced in 2000. These are 10-year, prospective, multi-centred studies in the US of smooth and textured silicone gel implants. The FDA, the government regulator required these studies as a condition for the re-approval of silicone gel implants in the US in 2006. It also required that Mentor and Allergan make available to patients the results of the core studies.Allergan’s results show a re-operation rate of 30 percent by seven years for 455 primary augmentation patients operated on by multiple surgeons. Forty percent of the re-operations were for one of two reasons: capsular contracture or displacement. The grade 3 and 4 contracture rate at ten years was 19.1%, with no difference between textured and smooth implants.

The core studies, ‘the very best data’ according to Professor Spear, reveal what happens in the medium term in the real world. With respect, no surgeon really knows what his or her contracture rate is unless they have participated in this kind of supervised trial. It is worth remembering this if a clinic claims they have lower rates than this unless they are using P-URE foam implants. Not surprisingly, Allergan does not promote the results of its core study. Because of the FDA requirement perhaps, it can be found deep in their North American websites. I cannot find it on their other international sites. The results for revision patients are substantially worse. Also, these were all round implants, Had teardrop implants been included in the studies it is likely the re-operation rate would have been even higher because of the risk of rotation with teardrop Implants which are not covered in P-URE foam. Polyurethane foam covered implants were not part of the core studies. However in an 18-year study in Argentina by Drs Vazquez and Pellon using Silimed P-URE foam covered implants all in front of the muscle a large number of patients were closely monitored for 15 years. Their results showed a contracture rate of one percent.

Critics argue that although this was also a prospective study over a long time with large numbers of patients, it is only one study and was not subject to the strict supervision of the core studies. This is true. But it is also true that every single study performed over the last 46 years which has compared smooth, textured and polyurethane foam-covered implants have, without exception, shown reduced contracture rates with the foam, usually by a very large margin.

Why no difference between smooth and textured implants?

Textured implants are supposed to adhere to the capsule like Velcro in the way that P-URE foam implants do and so reduce capsular contracture. But in fact most textured implants behave like smooth ones with no Velcro effect. I have asked many surgeons that of all the textured implants they have had to remove, how many had Velcro-like adhesion to the capsule as they are supposed to have? ‘Not many’ is the answer every surgeon I have asked has given.  It could be argued this was because they are a self-selecting group of patients as one of the implants needed removal due to complications.  If so, the other uncomplicated implant which is often removed at the same time for cosmetic reasons, should have been adherent.  But was it? Also consider patients who have textured implants removed solely for cosmetic reasons such as size change. Were these adherent? The answer to these questions is invariably ‘No’. World renown cosmetic plastic surgeon, Dr Elizabeth Hall Findlay from Canada, writing in the Journal Plastic and Reconstructive Surgery came to the same findings.

At our clinic, we have been monitoring the adhesion rate in in textured implants which we have removed for various reasons. The vast majority (80%) of textured implants do not adhere and of those that do, almost all had capsular contracture!

When lecturing South America I found most of the surgeons who do use textured implants there advise their patients to massage them in the post-operative period. Some Australian surgeons also advise massage of textured implants. The reason of massage is to stretch the pocket of a smooth surfaced implant so it remains larger than the implant and the risk of contracture compressing the implant is reduced. The FDA studies show that this does not prevent contracture.

However, the fact that surgeons are advising massage with textured as well as smooth implants shows that they do not believe any Velcro effect is occurring since massage would stop it occurring anyway by breaking up any attachment. Advising massage is a tacit admission that textured implants are behaving the same as smooth ones.

The reason P-URE Foam Covered Implants work

Why should the foam reduce contracture rates so much? This is revealed by microscopic analysis of the normal capsules associated with different implant surfaces. The collagen fibres which make up the capsule around both smooth and textured implants are strands aligned end on end, If a stimulus to contract occurs (whatever it may be), the fibres can shorten by sliding over one another concentrically around the implant, causing the shrink-wrap effect and the consequences of hardening or distortion of the implant.


Textured Implant Capsule: The collagen fibres are lined up end on end.

Smooth Implant Capsule: Collagen fibres are also aligned end on end just like with the textured implant.

P-URE foam-covered implants work because the foam becomes integrated into the full thickness of the capsule. The foam is a 3D matrix or lattice and the collagen fibres wrap around the foam struts.  They are no longer end on end but disjoined and cannot shorten over one another and cause the concentric shrinkage, Thus, contracture rates are literally decimated at least. Textured implants, even when they do adhere, can only at best affect the capsule/implant interface as the texturing remains on the surface of the implant. This is insufficient to alter the full thickness of the capsular architecture and therefore to reduce contracture rates.


P-URE foam Implant capsule: Completely different to smooth and textured implant capsules with the collagen fibres disjointed and not end on end. This stabilises the capsule and dramatically reduces the risks of capsular contracture.

With P-URE foam implants, a strong Velcro effect between the capsule and the implant invariably occurs.  When removing these implants after some months it is necessary to release this attachment between the implant surface and the capsule. A removed implant is no longer covered in foam as this now resides in the capsule. This Velcro effect creates a stable marriage between the implant and the capsule, supporting and stabilising the implant. Rotation is rare and the medium to long-term downward displacement, commonly seen to a greater or lesser extent with smooth and textured implants, is much reduced.

Safety

Are P-URE foam-covered implants safe? Unequivocally, yes. Evidence accumulated over 48 years of experience In patients with P-URE foam-covered implants has proved conclusively that they are safe and have no greater incidence of any complications compared with smooth and textured breast implants, The only exception to this is a temporary rash in about one percent of patients (see below).

About 20 years ago concerns were raised about whether the foam might degrade and cause problems. It was even suggested it might cause cancer. These concerns were subsequently fully investigated and it was confirmed the P-URE foam does not degrade into any harmful substances. It has also been shown conclusively that P-URE foam does not cause cancer in humans or any other species. Indeed it is also used in other human devices, such as pacemakers and prosthetic heart valves.

Disadvantages – Myths and Reality

In addition to the misconceptions concerning safety, other myths about these implants abound, such as you can’t remove them once they are in, they are too difficult to insert or you need a bigger incision. These are simply not true. What are the real disadvantages? The temporary rash over the breasts occurs in about one percent of patients in the second post-operative week and lasts for around one to two weeks. It is itchy and the patient is well so it is easily diagnosed and distinguished from infection. It is treated symptomatically with anti-histamines, has no long-term effects and does not recur. Removal of foam implants – although much less likely for much longer than with other implants – is sometimes, but not always, slightly more difficult than with non-foam implants. It is however perfectly possible. Claims that you need to remove breast tissue with the implant are not true and sometimes made to dissuade patients from having the safest implants by those unable or unwilling to use them. It typically takes a few minutes to remove a P-URE foam implant as opposed to a matter of seconds to remove the non adherent smooth and textured implants. If you have any doubts about this (and a stong stomach!) you can see me removing a foam implant at


If all of the implanted material needs to be removed then a complete removal of the capsule will be required if the implants have been in for more than three weeks as the foam will have started to integrate into the capsule. In cases of infection this is not always necessary. As with other implants, removal of the prosthesis alone and appropriate antibiotic treatment is usually enough to allow successful re-implantation after three months.

Some people claim P-URE foam implants are too firm. This is also not true. Two patients (one with large implants and the other with proportionate implants) demonstrate how soft and mobile their P-URE foam implants are in our video gallery. Some patients will have firmer breasts than others after implants regardless of the type of implants they choose due to their specific anatomy. Some silicone gels are firmer than others regardless of the surface of the implant but one thing is certain, because of the reduction in capsular contracture, and the higher percentage of grade 1 capsules with P-URE foam implants, they are much less likely to harden over time.

Using the P-URE foam implants successfully does require extra skiils from the surgeon. There is a learning curve for doctors using these implants. For example, they need to understand these implants stay where they are put. They do not ‘settle’ into the pocket. If they are too high the day after surgery they will remain so. Because smooth and textured implants often do ‘settle’, subconsciously surgeons may tend to put them in slightly high to allow for this. When surgeons start using the foam, if they are not made aware of this they may place the implants too high. Once this is appreciated by the surgeon it is actually an advantage since it affords better control and predictability of final implant position.

There are other technical adaptations which surgeons need to make to give patients good results with the P-URE foam implants and patients need to make sure their surgeon has plenty of experience in their use. Dr Daniel Fleming introduced these implants to Australia and has the most experience in using them.

Use In Revisional Procedures

The predictability of placement can be helpful when treating displacement, rotation and synmastia (implants meeting in the middle) as the implant does not exert the same pressure post-operatively on any areas of the pocket which may have been closed with stitches. Rotation of anatomical (teardrop) implants has not been described with Polytech’s P-URE foam implants.

If a patient has a grade 3 or 4 capsular contracture, the gold standard treatment is the creation of a virgin tissue to implant interface and the use of P-URE foam implants. This is either achieved by making a new pocket, total removal of the capsule (capsulectomy) or a plane change (in front of the muscle to behind or vice versa), depending on the specific circumstances of the patient. Such treatment will reduce her risk of recurrent contracture to two percent after seven years even though she has already had a contracture. When you compare this to the risk of developing capsular contracture with a non-foam implant in a new patient having her first augmentation, 19.1% at ten years, the advantages of the foam are even more obvious.

Capsulotomy (an incision of the contracted capsule to allow it to expand) is a less complicated and much easier operation and therefore a tempting option for both surgeons and patients. Unfortunately, if a capsulotomy only is performed and a new tissue to implant interface not created, the foam is unable to exert the same effect on the existing capsule and recurrence is increased to 50 percent.

Personal Experience and Conclusions

I have used these implants for 12 years in both primary and secondary patients. Our clinic has used them in more than 2000 patients and we now use them exclusively. They are not a panacea but complications and the need for repeat operations has been dramatically reduced. Our results have simply mirrored the results of surgeons overseas who have used these implants for longer than me. Whereas previously I was loath to use teardrop implants unless they were absolutely necessary because of the risk of rotation, now the majority of implants I use are teardrop. The ability to control three dimensions with a teardrop implant (height, width and projection) rather than only two with a round (diameter and projection) allows me to achieve better results in many patients.

All elements of the operative plan are critical to optimising outcomes for breast augmentation patients. The choice of implant surface is a critical part of the plan, one which is entirely controllable and has predictable consequences. It is important that my views about P-URE foam-covered implants are not only based on the fact but are also shared by other world experts experienced in their use:

Analysis by Dr Neal Handel, Assistant Clinical Professor in Plastic Surgery at the University of California, Los Angeles, has found that ‘contracture is a progressive phenomenon, and the longer any group of patients is followed, the greater the cumulative risk of developing contracture’.

In Handel’s words, ‘This contradicts the widely held belief that if patients remain contracture-free for a year or two they probably will not develop significant contracture. This finding may also have some relevance in understanding the cause of capsular contracture. If the risk of contracture persists for many years after implantation (as it appears to), it seems less likely that it is related to acute events such as bacterial contamination, surgical technique, drains, antibiotics or other ancillary measures that have a short-term impact and more likely related to some chronic effect of implants on adjacent tissue.’

Handel also reviewed all of the breast implant patients from his practice covering the period 1981-2004. 345 smooth implants, 618 textured and 568 polyurethane foam-covered implants were used.

“Based on analysis of our data, we conclude that the contracture rate after all types of breast surgery is dramatically lower with polyurethane foam covered implants than with smooth or textured implants”

“There is nothing…to suggest that polyurethane foam, or its in vivo breakdown products, pose a threat to the health or safety of patients. Polyurethane implants have measurable advantages over smooth and mechanically textured gel-filled prostheses and do not appear to be associated with an increased risk of complications or morbidity.” (Handel, N. Long–term safety and efficacy of polyurethane foam-covered breast implants. Aesthetic Surgery Journal Vol.26 2006)

Dr Guillermo Vasquez, a plastic surgeon from Buenos Aires in Argentina reported his experience using these implants in 1,257 patients over an 18 year period.

He concluded “…this implant reduces capsular contracture to under 1%” “We believe that the above-mentioned percentage and the low incidence of other complications make the use of these implants one of the best options for augmentation”. (Vasquez, G. An eighteen year experience using polyurethane-covered breast implants. Aesthetic Plastic Surgery 2007)

Dr Roderick Hester, Dr John Tebbetts and Dr Patrick Maxwell from Georgia, Dallas and Nashville respectively, reviewed the literature on and their experience with polyurethane covered breast implants.

The senior author concluded “During the span of this author’s practice, he has never been able to match the number and quality of superior results exemplified by these patients when using other devices.” (Hester T.R., Tebbbets, J. Maxwell, G.P. The polyurethane-covered mammary prosthesis: Facts and fiction (II). Clinics in Plastic Surgery Vol.28 2001. )

Professor James Frame, Professor of Aesthetic Plastic Surgery in London, has stated, “I think the evidence in favour of preferable use of PU covered implants is overwhelming compared to smooth or textured implants and it is clinically negligent to not put these facts to the patient.”

In August 2009, Dr Leroy Young, a senior plastic surgeon from St Louis in the US, gave a presentation about P-URE foam-covered implants at the American Society of Aesthetic Plastic Surgeons annual breast meeting in Santa Fe. Following the conference he commented in an email to me: ‘There were a number of surgeons present who had used the devices when they were available in the US and, unanimously, they said they were the best implants they ever used.’

The evidence clearly shows you can modify the effect of implants on the capsule and dramatically reduce the risk of the commonest complication and reason for re-operation by choosing one implant surface (with a 48 year proven safety record) over another. The evidence also suggests it is highly likely you can substantially reduce displacement, the second-most common complication and reason for re-operation as well. It is difficult therefore to justify not using P-URE foam covered implants. At the very least patients should be informed about them so they can make their own decision. Certainly, when patients are given the evidence to consider they virtually all choose foam. If a surgeon does not offer this option to their patient they will need to ask themselves how they will respond to the next contracted or ‘bottomed-out’ patient who asks: ‘Why didn’t you tell me about the P-URE foam implants?’

These implants:

are the safest implants
have fewer complications
last longer before the need for replacement
have the most comprehensive warranty and
give the greatest chance of the best result.
In conclusion, having done her research, the informed breast implant patient inevitably realises there no logical reason to choose anything other than P-URE foam-covered implants.

A comprehensive reference list available on request.

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