Aesthetic cranioplasty often involves the coverage of large skull areas with alloplastic material. Whether it be PMMA or hydroxyapatite cements or with today’s custom 3D generated silicone implants, a fairly large amount of material can serve as a solid interface between the overlying scalp and the underlying cranial bone. As the scalp has an excellent blood supply through major arterial pedicles, the placement of such skull implants do not pose any vascular compromise to the scalp tissues in general or to hair growth in particular.
But there are risks to consider in the use of larger skull implants such as scalp tissue adherence and the development of seromas (fluid collections) after surgery. It is easy to see how these might occur since the scalp normally sticks back down to bone and seals its lymphatic channels by such healing. Any implant material, however, creates a surrounding capsule to which the scalp sticks but the capsule itself does not adhere to the material as firmly as natural scalp tissue sticks to bone. The capsule itself can also be a source of chronic fluid egress particularly in secondary surgery where an established capsule exists.
While the development of these skull implant issues are rare in my experience, there is a simple intraoperative manuever to help their prevention. The placement of many small holes through the material, known as perfusion holes, can help re-establish a fibrovascular connection between the scalp and the underlying skull bone. The more holes that are placed the more small connections that are made. In solid PMMA bone cement 2mm holes are made with a handpiece and burr. It is only necessary to go through the material and not into the bone. But there is no harm in doing so if the outer cortex of the bone is penetrated.
In custom silicone skull implants these perfusion holes are made with a 2mm or 3mm skin punch. This is easy and quick to do. How many perfusion holes to make is not precisely known but more is probably better than less.
The placement of perfusion holes in aesthetic skull implants, in addition to recreating a vascular connection, also serves to have a quilting effect. With the tissue ingrowth through the holes, a small soft tissue ‘anchor’ is created. This in effect takes a large subcapsular space around the implant and turns it into many smaller compartments. This serves not only to anchor the overlying scalp to the implant but also can have a seroma prevention effect.
It ‘s exactly a year – to the day – you performed surgery on me for my dysmorphic skull. (anterior and posterior cranioplasty with HA and PMMA) I want to thank you for the excellent conditions under which happened for my surgery and your warm welcome and your patience and amiability in answering all my questions. All these factors helped me to have the surgery for my long-standing skull disfigurement.With hindsight I can evaluate the result to be 80 % of what I hoped (percentage by which I am very satisfied because of the severity of dysmorphia, a persistent posterior flattening ) and I am convinced that this is the maximum that we can correct. I am very surprised at the result of the anterior cranioplasty, it is perfect and impossible to notice. My scar is better than before (Except for my 13 year old daughter, nobody noticed anything) I want to thank you for getting me out of a very long nightmare ….I found again the joy of living…thank you very much!!
Perhaps surprising to some, the shape of one’s head/skull to some can be as disturbing as just about any other face or body part. Head shape concerns of areas of flatness, too much projection or asymmetries from either natural skull development or from prior surgery or trauma affect people’s self-esteem. Skull reshaping or cranioplasty can offer some very effective improvements for many of these skull shape concerns that can be tremendously gratifying as this patient’s e-mail demonstrates a year after surgery. Patients often know quite specifically what about their head shape they do not like and can draw a diagram of how they would like it changed. (as this patient did) Augmentation of the skull can be done more effectively than reduction in most cases if the overlying scalp permits the expansion.
Of all the non-craniosynostotic developmental skull deformities that exist, by far the most common is occipital plagiocephaly. This refers to a flattening on one side of the back of the head. While the deformity may be greatest on the flattest part of the occiput, its effects go beyond the flat skull area. Usually there is some compensatory bulging on the opposite normal side of the occiput as well as on the temporal side of the flattened side anterior to it. The ear positions can also be seen to be asymmetric with the ear on the flattened side more anterior than the opposite ear and may have some slight protrusion to it as well.
While a flat back of the head in an adult poses only an aesthetic deformity, to some so afflicted it can be more than just a casual asymmetric concern. While an occipital plagiocephaly in a balding male or one who shaves his head appears obvious and their concern is visible, I have seen an equal number of women with full heads of hair that are considerably bothered by it as well and adjust their hairstyles to accomodate for the aesthetic skull deformity.
The correction of an occipital flattening is done by building up the back of the head with a cranioplasty material. In and of itself, it is a fairly straightforward procedure to accomplish skull symmetry as long as one has complete visual access. Using a traditional and full ear to ear incision with peelback of the scalp does allow this exposure but many patients do not desire a full transverse scalp scar. This would be particularly true in almost all men due to their hair density and scar exposure concerns. It is always paramount to avoid trading off one aesthetic scalp/skull problem for another.
Adapting an occipital cranioplasty procedure through a smaller incision has been necessitated over the years because of scar concerns. It is possible to do the procedure but it necessitates several technical adjustments or modifications to that of a full open cranioplasty. It does not require special instrumentation but an intimate working knowledge of the handling properties of the various cranioplasty materials.
First and most importantly only one cranioplasty material has the working properties to be inserted through a small incision and molded into shape externally by scalp manipulation. PMMA or polymethylmethacrylate, acrylic bone cement, can be mixed into a putty which at a certain point in its set is not too loose but has not started to fully polymerize either. It is this window in the setting of the material that can permit it to be inserted through a smaller incision and still have adequate flow properties to be molded once inside. Unfortunately, none of the HA or hydroxyapatites have these working propertiues to be of great value for this approach. I have tried every HA material available and they all come up wanting, either in too short of set times or lack of adequate flow characteristics.
While a cranioplasty material can not really migrate around or away from its pocket on the bone, like other implants in soft tissues, some anchorage to the bone is always a good idea…even if it is just for psychological reassurance The best way to do that is to place small 1.5mm self-tapping titanium screws into the bone leaving them slightly above the bone surface. This will allow the PMMA to flow around them and lock onto them while it is curing. Since PMMA never really bonds to the skull bone, although there is some justification to calling it a bone cement since it does have some stick to it, this small screw fixation certainly prevents any micromovement. As long as too many screws are not placed or the screws are not too big, it is really quite easy to pop the implant off the bone later should that ever be necessary. In essence, their use does not make secondary removal unduly difficult.
Once the PMMA material is inserted, the scalp incision needs to temporarily stapled together. This then allows one to shape the material and feather its edges by external scalp manipulation. There usually is a few minute window to do the molding. While in years past the final set of PMMA was associated with very high heat release, this is no longer true. The exothermic reaction is very minimal with newer formulations so there is no risk of thermal injury to the scalp tissues. Once shaped and set, the staples are removed and partial visual assessment can then be done internally. (although this will be very limited as the material now occupies the entire pocket and the small incision makes it very hard to look over all the augmented area)
One advantage to the small incision cranioplasty is that the risk of difficulty with incisional closure is less because the molding is usually done away from it. This prevents the risk of encountering an incision that can not be closed due to the augmentation volume. When possible it is always best to have an incision in which no cranioplasty material lies underneath it. (ideal but not always possible)
The small incision occipital cranioplasty can be a very effective method of skull augmentation. Patients can have a very quick recovery and very minimal discomfort. But it is very technique dependent and requires good experience with more open methods of cranioplasty before attempting it through limited access.
Skull reshaping surgery is done to create a more normal skull shape and contours. It achieves this goal through the application to the outside of the skull of either augmentation (by adding materials), reducing bone or a combination of both techniques. Most skull reshaping techniques require an open incisional approach to be done.
The following postoperative instructions for skull reshaping surgery are as follows:
1. Skull reshaping surgery has a surprisingly minimal amount of postoperative discomfort. Pain medications are prescribed should you need them and you should take them as directed on the label, usually 2 tablets every 3 to 4 hour as needed. Many patients only use Tylenol; or Alleve after the first few days of surgery.
2. There will be a circumferential head wrap applied at the end of the procedure. This is to be worn for the first night after surgery and can be removed the next day. Thereafter no dressings are needed. You may take it off the next day to shower.
3. In some cases of skull reshaping surgery, a drain will be used for the first day after surgery. This very small tube will be connected to a small bulb which collects any fluids. Empty the bulb as directed and there is NO need to measure the amount of fluid that comes out. In most cases of skull reshaping surgery, the bulb usually does not fill enough to be emptied more than once. The drain will be removed the day after surgery.
4. The scalp incision will be closed with either resorbable sutures, permanent sutures or small metal staples.There is no need to apply any antibiotic ointment to the incision, just leave them dry. Resorbable sutures do not need to be removed. Permanent sutures and staples will be removed 7 to 10 days after surgery. You may shower 48 hours after surgery and wash your hair.
5. You may wash your hair 48 hours after surgery. It is alright to get the sutures or staples wet. Dry and style your hair as desired. Be careful combing your hair so you do not catch the comb in the sutures or staples.
6. Strenuous physical activities and working out should wait for at least one week after surgery. While you can not harm the result by anything you do, wait until you feel better before exerting yourself.
7. You may eat and drink whatever you like right after surgery. Focus on liquids and soft foods for the first few days after surgery.
8. You may return to work and any non-strenuous physical activity as soon as you would like based on your comfort level.
9. You may drive when you feel comfortable and can react normally and are off pain medication.
10. If any scalp or incisional redness, tenderness, or drainage develops after the first week of surgery, call Dr. Eppley and have your pharmacy number ready.
Every plastic surgery procedure has numerous issues that every patient who is undergoing a procedure should know. These explanations are always on a consent form that you should read in detail before surgery. This consent form, while many perceive as strictly a legal protection for the doctor, is actually more intended to improve the understanding of the various skull reshaping procedures. The following is what Dr. Eppley discusses with his patients for these procedures. This list includes many, but not all,of the different outcomes from surgery. It should generate both a better understanding of the procedure and should answer any remaining questions that one would have.
There are no alternatives to surgical skull reshaping. Some small skull defects may be treatable by a fat injections or bone cements placed through a minimal incision injection approach. High spots or skull reduction can not be reduced by a non-incisional approach.
The goal of skull reshaping surgery is to create a more normal appearing skull contour. In some cases, this may require building up the bone, reducing raised areas or a combination of both reshaping techniques to get the optimal skull contour.
The limitations of any cranioplasty procedure are how much of an incision can the patient tolerate (access and exposure), how much the skull can be built up based on the scalp’s ability to stretch and the thickness of the skull bone when reductions are being done.
Expected outcomes include the following: temporary swelling of the scalp even extending down into the face, scalp skin numbness, a permanent scalp scar, the implantations of various biomaterials for augmentation/buildup including microcrew anchorage and months of healing and tissue settling until the final result is seen in all aspects. Healing of any cranioplasty procedure is a process and the minimal amount of time to judge the result is three months and may take as long as six months to see the very final result in many cases.
Significant complications from skull reshaping surgery are very rare but could include infection. More likely but uncommon occurrences could include a wide scalp scar, potential hair loss along the incision, suture reactions along the incision edges causing local wound healing problems, edge demarcation/irregularities along any implant-bone interface, overcorrection of the skull contour, undercorrection of a skull contour, and asymmetries and irregularities of the skull contour. Any of these risks may require revisional surgery for improvement.
Should additional surgery be required to revise a scalp scar, adjust a bone or implant contour or perform aesthetic adjustments of the initial skull reshaping will generate additional costs.
One of the techniques for contouring of the skull is augmentative cranioplasty. This is where the skull or forehead is built out through the use of a variety of synthetic materials. While bone would seem to be a logical choice, it is associated with resorption when used as an onlay not to mention the need for a donor site. Synthetic materials offer contour stability, off-the-shelf ease of use and the elimination of a donor site. Even though there is a risk of infection with synthetics, their benefits far outweigh this very uncommon cranioplasty risk.
One of the most common cranioplasty materials is acrylic or PMMA. (poly methylmethacrylate) It has been used successfully for decades and offers a material strength that is similar to bone and is virtually impact-resistant. It is used in orthopedics as a bone cement for joint prostheses but on the skull it does not have ‘cement’ capabilities. This means that the material does not bond to the bone or the overlying soft tissues. Rather it forms a scar capsule around the material, particularly between the material and the underlying bone. This means that there can be small amounts of motion or instability of the cranioplasty material. In revision of pure onlay cranioplasties, it can be very easy to lift the material off of the bone. This material looseness may or may not cause any long-term problems.
Since a PMMA cranioplasty does not bond to the bone, I have always used an anchoring method for the material. The simplest method is to preplace small titanium crews into the outer table of the skull and leave them raised several millimeters. When the cranioplasty material is applied, the initial putty phase of the material wraps around and grabs the screwheads. Once cured, there is a rigid lock of the material to the bone. This prevents any chance of instability or shifting of the material on the skull’s surface.
This screw anchorage of cranioplasties can be used at any location on the skull. It is of particular value on the occipital (back of the head) region where the skull is exposed to the greatest amount of regular stress. (laying on the back of your head)
This cranioplasty fixation method is not as important with the use of other materials such as hydroxyapatite. While these materials are far weaker and minimally impact-resistant, they do have the ability to bond to bone so they have no risk of material movement or instability.
The desire for forehead reshaping in adults is done for three reasons. Most commonly, it is someone who has a residual forehead deformity due a congenital skull deformity. (e.g., craniosynostosis) As one gets older, or as hair loss occurs in men, the frontal skull deformity becomes more aesthetically obvious. Secondly, a frontal skull deformity exists due to an injury or after a neurosurgical craniotomy procedure has been done. Lastly, for those individuals going through a gender transition (female to male), the slope of the forehead or the prominence of the brows may be desired to be increased.
For any of these reasons, forehead augmentation (frontal cranioplasty) involves expansion of the existing bone boundaries. It is not practical to try and do this by manipulating the skull bone in most cases, as there is an easier and more effective solution…..build up the bone with synthetic materials. While I always try to avoid synthetic materials when it is possible, their use in forehead augmentation is the only practical and reasonable option in the vast majority of cases. (onlay cranioplasty) As such, a good working knowledge of the available synthetic materials for the skull is important.
Fortunately, adding to the forehead bone is not a technically difficult procedure. The two questions about it are: what type of material to use…and access to the bone. Forehead augmentation has two very moldable and adaptable materials to build it up with. Traditional PMMA (polymethylmethacrylate) has been around for a long time and has the advantages of a very low cost, high resistance to impact forces, and ease of intraoperative contouring. Its main disadvantage is that some patients over time can develop some low-grade reactions to it and it may get loose, become infected or the overlying forehead skin may thin, although these issues are uncommon. It does generate a lot of heat during its setup (polymerization) but this is managed by cool water irrigation. Newer ‘more natural’ materials such as hydroxyapatite cements (HA) have been available over the past 10 years. HA offers the advantage of being a more natural, less synthetic material as its structure more closely resembles that of bone. Its disadvantages are that it is considerably more expensive, has a low resistance to impact (easily shatters), and is a bit tricker for the plastic surgeon to use. It generates no heat during its setup but is very sensitive to moisture and is easily deformed and pushed around during its set up phase. At this time, there are no long-term clinical studies that give a decided advantage to one material or the other.
Other synthetic options include pre-made or custom-made synthetic implants. They can be made of either silicone rubber (most common), gore-tex, or poplyethylene. In most cases, these would have to be prefabricated based on a skull model of the patient to get the best and most exacting fit. Any irrergularities will be obvious in the contour of the forehead so a precision fit is essential. I don’t find that these onlay custom implants offer any advantages over PMMA or HA in terms of better long-term outcomes or reduced risks of complications.
Regardless of the material used, synthetic forehead augmentation is all about access. The asiest and most predictable way to place it is through an open scalp incision. While this is the best and easiest way to do, there is always the cosmetic trade-off of this scar. When more limited or endoscopic access methods are used, one has to use PMMA because it is easier to mold through intact skin and will predictably stay where it is placed and molded. Endoscopic forehead augmentation is a more limited procedure due to its more limited visual access.
Expanding or enlarging the forehead to a more desireable contour is most commonly considered in adults or teenagers who have had a congenital skull deformity. Most of these had some form of craniosyostosis, with or without early craniofacial surgery, and are now left with forehead irregularities, depressions, or a forehead that severely slopes to the temple area making it look too narrow. Other needs for forehead augmentation are from previous trauma cases with frontal bone fractures, neurosurgery patients with craniotomy defects, and rarely a female to male facial conversion patient.
All forehead augmentations use some form of synthetic material to add on top of the bone. The use of acrylic or PMMA, a liquid plastic that hardens after being mixed, has been around for many decades and consistently works well. The more recent uses of bone cements or HA (hydroxyapatite), which similarly harden after mixing, are of more recent use. I have used a lot of each and either PMMA or HA has its own set of advantages and disadvantages. PMMA is less expensive, sets up more reliably in surgery, and can be injected through an endoscopic technique (for small areas) if one wants to avoid a large scalp scar. It also sets up very firmly and gets as hard as any thick plastic material. Its biggest disadvantage is that it is truly a non-natural synthetic material and its long-term implantation may have higher risks of rejection or infection. HA is a more natural material that is similar to bone in structure but it sets up slower and can be more difficult to work with through small incisions. It usually is best placed through a more open scalp incision. Once set, HA is softer than PMMA and if exposed to a large impacting force, it will potentially shatter like a ceramic dinner plate. My decision as to what material to use for any particular forehead depends on the operative technique. For open forehead approaches, I will use HA. For endoscopic techniques, I will use PMMA.
Building up the forehead is similar to sculpting with clay. The forehead bone is exposed and the chosen material is applied and molded into the shape one desires. Whether it is done through an open approach when one uses the fingers to mold and shape or done through an endoscopic technique where the fingers mold it through the forehead skin, the procedure is not difficult and provides an immediate result that should not change over time. The most difficult decision for the patient is whether a larger scalp incision is acceptable or whether the endoscopic ( a few small scalp incisions) approach is preferred. Smaller or spot forehead augmentations can be done endoscopically. Larger or more complex forehead augmentations are best done with an open scalp approach.
Dr. Barry Eppley is an extensively trained plastic and cosmetic surgeon with more than 20 years of surgical experience. He is both a licensed physician and dentist as well as double board-certified in both Plastic and Reconstructive Surgery and Oral and Maxillofacial Surgery. This training allows him to perform the most complex surgical procedures from cosmetic changes to the face and body to craniofacial surgery. Dr. Eppley has made extensive contributions to plastic surgery starting with the development of several advanced surgical techniques. He is a revered author, lecturer and educator in the field of plastic and cosmetic surgery.