Facial feminization surgery: current state of the art

Abstract

Facial feminization surgery (FFS) is a group of surgical procedures; the objectives of which are to change the features of a male face to that of a female face. This surgery does not aim to rejuvenate the face. FFS is carried out almost exclusively on transsexual women (males who are transitioning into females) and who have gender dysphoria. Some non-transsexual women may undergo some feminizing surgical procedures if they feel that they have male facial characteristics. Most transsexual women will have lived in role for sometime and they often undergo FFS before any other form of gender reassignment surgery as it assists them in passing as a female and integrating into everyday society. Various specific facial surgical procedures are utilized to feminize the face, often involving sculpture and contouring of the facial skeleton. These include correction of the hairline by scalp advance, contouring the forehead, brow lift, rhinoplasty, cheek implants, resection of the buccal fat pads of Bichat, lip lift and lip augmentation with dermis graft, mandible angle reduction and taper, genioplasty and thyroid shave. This article discusses the current state of the art in facial feminization surgery.

Facial feminization surgery (FFS) is a group of surgical procedures; the aim of which is to change the features of a male face to that of a female face. FFS was originally popularized and pioneered by Dr. Douglas Ousterhout of San Francisco, California, USA in the 1980s and 1990s.

Ousterhout examined several hundred dry skulls in the Atkinson skull collection at the University of San Francisco. Characteristics identified in female and male skulls were identified in female patients demonstrating both male and female forehead features. Treatment protocols were produced based on these differing features and various surgical techniques developed, some of which were also performed in gender female patients who also requested improvement in their forehead contour. These procedures are especially useful in transsexual women in whom the forehead often requires contouring.

Female and male faces are quite different in terms of size and shape, but in feminizing the male face it is important to appreciate that the size of the face has to be in proportion to the rest of the body.

Analysis of the female face demonstrates that it is more heart-shaped or triangular with the base of an inverted triangle being represented by a line drawn between the maximum prominence of each zygoma and the apex of the triangle being represented by the chin point. The female face is softer and more rounded or oval-shaped, with soft, round, curving forms. Male faces are more square and angulated with a strong jaw and chin often with an M-shaped hairline ( Fig. 1 a and b ). The chin and lower jaw is usually longer in the male by as much as 20% and is often, but not always, more prominent in profile.

Fig. 1
(a and b) Line illustrations demonstrating the differences between male and female faces. The male face is square and angulated with sharp lines and a strong jaw, while the female face is curved, round, oval and heart-shaped with smooth lines and smaller overall.

The male forehead often exhibits significant frontal bossing, which may partly be due to a large frontal sinus, but may also be due to thick supra-orbital ridges. In addition, the angle formed at the glabella between the frontal area of the forehead and nose is often acute as opposed to in the female where it tends to be much more obtuse ( Fig. 2 ).

Fig. 2
Differences between male and female foreheads.

Female eyebrows are arched, especially in the lateral third area and sit well above the superior orbital rim, while the male eyebrow is straighter and tends to sit at the level of the superior orbital rim.

Female noses are smaller and shorter with narrow bridges and narrow ala bases, often with upturning of the nasal tip giving rise to a more obtuse naso-labial angle.

Male cheeks are flat whereas female cheeks can be quite prominent, being further anterior and higher with some cheek hollowing beneath, which provides further accentuation.

Female upper lips are fuller and shorter with good show of the vermillion and a well-formed Cupid’s bow. Maxillary tooth show is greater in females due to these features and characteristics.

Male chins are often long, square and angulated as opposed to female chins, which are shorter, narrower and more pointed ( Fig. 3 a and b ).

Fig. 3
(a and b) Differences between male and female chins.

The male mandible has a prominent angle with lipping of the bone due to the masseter muscle attachments and it is wider than in the female. The external oblique ridge is thick and the masseter muscle is bulkier.

The thyroid cartilage is more prominent in the male and at the notch forms an angle of 90° as opposed to the female where it forms an angle of 120°, which is the reason for it being less pronounced. A prominent thyroid cartilage is an extremely masculine characteristic, hence the popularity of the thyroid shave in this group of individuals.

Surgical procedures

Numerous surgical procedures can feminize the face, including forehead reduction, hairline correction by scalp advance, brow lift, rhinoplasty, cheek implants, resection of the buccal fat pads of Bichat, lip lift and augmentation with dermis graft, genioplasty, angle shave and taper and thyroid shave. For the purposes of this paper only those procedures specific to FFS will be discussed in detail: forehead reduction, scalp advance, cheek implants, buccal fat pad removal, lip lift and dermis graft, genioplasty, angle shave and taper and thyroid shave. Many of these procedures can be undertaken all at once or individually, depending on the facial requirements of the particular patient.

Forehead reduction

Ousterhout analysed several hundred dry skulls for patterns of shape and recognized anthropological features that differentiated the female from the male skull. These differences were compared with patients with different patterns of facial contour. He classified forehead shape and contour into three distinct groups.

Group I has mild to moderate excessive projection of the brow and abnormal bossing. There are no frontal sinuses, or the bone anterior to the frontal sinuses is so thick that its reduction will not compromise the sinus air space. The reduction is achieved simply with an acrylic burr in order to achieve the desired contour.

In Group II the brows are normal, mildly or moderately projected and there is thick bone anterior to the frontal sinuses. This bone can therefore be reduced as in Group I patients, but may become quite thin. When the bossing is reduced there may be a forehead concavity superior to the bossing, which may require filling with bone cement to feminize this area of the forehead. Ousterhout originally described the use of methylmethacrylate onlay implants in this group of patients. This has now been superseded by the use of bone cement.

Group III patients have excessive brow fullness and the requirement for the anterior table of the frontal sinus to be set back into a more retruded position. The anterior table has to be osteotomized, reshaped and fixed with mini-plate osteosynthesis. Planning is undertaken by use of computerized tomography (CT) scanning or cone-beam CT to measure the dimensions of the sinus precisely to plan the osteotomy cuts ( Fig. 4 a and b ). It must be borne in mind that the frontal sinus is not a symmetrical structure and one side may be larger than the other. In the glabella region the male profile characteristic is of an acute angle formed between the frontal sinus anterior wall and dorsum of the nose. This must be reduced to a more oblique angle to feminize this area of the face adequately. Therefore, for Group III cases, it is essential to osteotomize the inferior aspect of the anterior table of the frontal sinus precisely at the glabella and immediately above the radix area of the nose. In the author’s experience, this group of patients forms the majority of cases requiring forehead contouring.

Fig. 4
(a and b) Cone-beam CT scans of frontal sinus showing preoperative planning measurements.

In all cases access is via a coronal flap. The main decision in terms of flap design is if a scalp advance to correct the hairline is required. If it is not, then a standard coronal incision is made in a ‘stealth’ fashion to disguise the resulting scalp scar. In patients requiring hairline correction a trichophytic incision (as opposed to a pre-trichial incision) is made tangentially through the hair follicles 4–5 mm behind the hairline that will encourage hair growth through the resulting scar ( Fig. 5 a and b ). The incision follows the temporal hairline, which often requires advancement and then runs in a posterior direction into the hair-bearing area and down towards the ears. The hair is not shaved in this group of patients, but is simply parted in the temple areas and tied up in bunches.

Fig. 5
(a) Trichophytic incision; note relationship of tangential incision to hair follicles. (b) Pre-trichial incision; note relationship of parallel incision to hair follicles.

Standard tumescent solution is injected into the scalp and the flap raised avoiding injury to the frontal branches of the facial nerve. The dissection proceeds in the sub-periosteal plane approximately 4–5 cm superior to the glabella and the entire frontal area down to the glabella is exposed including the frontal processes of the zygomas and the superior orbital rims, dissecting 1 cm into the roof of each orbit. At this point in the dissection the supra-orbital nerves may need to be dissected or osteotomized out of their foramina in order to expose the entire superior orbital rims.

In Group I and II cases, extensive reduction of the bossing, including the frontal processes of the zygomas with an acrylic trimming burr on a fast motor is all that is required, but the addition of bone cement may be required in Group II cases. The lateral superior orbital rims are contoured to reduce any bony infringement and to expand the orbital perimeter.

Group III cases all require osteotomy of the anterior table of the frontal sinus. The dimensions of the anterior table cuts are marked out on the bone from the known CT scan measurements, taking into account any asymmetry of the sinus. The cuts are made with a Toller fissure burr or sagittal saw inclined obliquely at an angle greater than 45° to the bone surface and facing towards the sinus at all times in order to ensure correct positioning. Once the cuts are completed, a fine osteotome is used to separate the anterior table from the forehead, with great care being taken not to fracture the bone plate.

The frontal sinus cavity is inspected and the lining preserved though the lining of the sinus is always torn in lifting out the bone plate, which is of no consequence. Bony septa on the inside of the anterior table are trimmed as are septa within the sinus cavity. All bone debris is thoroughly washed out with saline irrigation.

The anterior table is replaced with its inferior aspect placed into a retruded position in a ‘tongue-and-groove’ fashion, which very effectively eradicates the frontal bossing. The surrounding bone is contoured, but a precise fit is not required as steps or deficiencies cannot be appreciated on palpation via the scalp. On occasion the anterior table will itself need to be osteotomized transversely as the superior edge can otherwise protrude too far when the anterior table plate of bone is particularly large.

Fixation is by means of titanium 1.3 mm mini-plate osteosynthesis using three X-shaped plates to stabilize the bone plate ( Fig. 6 a and b ).

Fig. 6
Forehead III. Intraoperative photograph demonstrating (a) anterior table removed and underlying frontal sinus and (b) inset anterior table after preparation and fixation.

All groups of patients undergo orbital rim contouring in which the outer third of the superior orbital rim is reduced to increase the dimensions of the anterior orbital rim.

Some authors advocate preservation of the periosteum overlying the anterior table bone plate and carrying out the dissection in the sub-galeal plane. While this will not aid in the revascularization of the bone plate, it is useful in employing a compression technique to flatten the bone plate rather than osteotomizing it and in so doing the periosteum adheres to the bone fragments, maintaining continuity. Preservation of the overlying periosteum also assists in fixation of the bone plate with sutures instead of mini-plate osteosynthesis.

Appropriate postoperative antibiotics are prescribed. Patients are instructed not to blow their nose for 10 days postoperatively, otherwise air may be introduced into the frontal sinus leading to surgical emphysema and possible infection.

Scalp closure will be discussed under the section on scalp advance though the periosteum in forehead reduction cases is sutured back over the bone plate with 3/0 Vicryl Rapide suture (Ethicon Inc, Somerville, NJ, USA) to aid in revascularization.

Complications of the forehead reduction procedure include damage to the supra-orbital nerves causing scalp anaesthesia. Very rarely, the frontal branches of the facial nerves may be injured resulting in frontalis weakness or paralysis. Rarely, frontal sinus infection may occur. Eyelid bruising and oedema along with chemosis are common, but are temporary. The feared complication of total loss of the anterior table due to bone resorption or infection seems to pose negligible risk.

Forehead reduction

Ousterhout analysed several hundred dry skulls for patterns of shape and recognized anthropological features that differentiated the female from the male skull. These differences were compared with patients with different patterns of facial contour. He classified forehead shape and contour into three distinct groups.

Group I has mild to moderate excessive projection of the brow and abnormal bossing. There are no frontal sinuses, or the bone anterior to the frontal sinuses is so thick that its reduction will not compromise the sinus air space. The reduction is achieved simply with an acrylic burr in order to achieve the desired contour.

In Group II the brows are normal, mildly or moderately projected and there is thick bone anterior to the frontal sinuses. This bone can therefore be reduced as in Group I patients, but may become quite thin. When the bossing is reduced there may be a forehead concavity superior to the bossing, which may require filling with bone cement to feminize this area of the forehead. Ousterhout originally described the use of methylmethacrylate onlay implants in this group of patients. This has now been superseded by the use of bone cement.

Group III patients have excessive brow fullness and the requirement for the anterior table of the frontal sinus to be set back into a more retruded position. The anterior table has to be osteotomized, reshaped and fixed with mini-plate osteosynthesis. Planning is undertaken by use of computerized tomography (CT) scanning or cone-beam CT to measure the dimensions of the sinus precisely to plan the osteotomy cuts ( Fig. 4 a and b ). It must be borne in mind that the frontal sinus is not a symmetrical structure and one side may be larger than the other. In the glabella region the male profile characteristic is of an acute angle formed between the frontal sinus anterior wall and dorsum of the nose. This must be reduced to a more oblique angle to feminize this area of the face adequately. Therefore, for Group III cases, it is essential to osteotomize the inferior aspect of the anterior table of the frontal sinus precisely at the glabella and immediately above the radix area of the nose. In the author’s experience, this group of patients forms the majority of cases requiring forehead contouring.

Fig. 4
(a and b) Cone-beam CT scans of frontal sinus showing preoperative planning measurements.

In all cases access is via a coronal flap. The main decision in terms of flap design is if a scalp advance to correct the hairline is required. If it is not, then a standard coronal incision is made in a ‘stealth’ fashion to disguise the resulting scalp scar. In patients requiring hairline correction a trichophytic incision (as opposed to a pre-trichial incision) is made tangentially through the hair follicles 4–5 mm behind the hairline that will encourage hair growth through the resulting scar ( Fig. 5 a and b ). The incision follows the temporal hairline, which often requires advancement and then runs in a posterior direction into the hair-bearing area and down towards the ears. The hair is not shaved in this group of patients, but is simply parted in the temple areas and tied up in bunches.

Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Facial feminization surgery: current state of the art
Premium Wordpress Themes by UFO Themes