Rhinoplasty - Surgical Précis For Rhinoplasty - Surgical Techniques

Surgical Techniques

The effectiveness of a rhinoplastic reconstruction of the external nose derives from the contents of the surgeon’s armamentarium of skin-flap techniques applicable to correcting defects of the nasal skin and of the mucosal lining; some management techniques are the Bilobed flap, the Nasolabial flap, the Paramedian forehead flap, and the Septal mucosal flap.

I. The bilobed flap

The design of the bilobed flap derives from the creation of two (2) adjacent random transposition flaps (lobes). In its original design, the leading flap is applied to cover the defect, and the second flap, is emplaced where the skin flexes more, and fills the donor-site wound (from where the first flap was harvested), which then is closed primarily, with sutures. The first flap is oriented geometrically, at 90 degrees from the long axis of the wound (defect), and the second flap is oriented 180 degrees from the axis of the wound. Although effective, the bilobed flap technique did create troublesome “dog ears” of excess flesh that required trimming and it also produced a broad skin-donor area that was difficult to confine to the nose. In 1989, J. A. Zitelli modified the bilobed flap technique by: (a) orienting the leading flap at 45 degrees from the long axis of the wound; and (b) orienting the second flap at 90 degrees from the axis of the wound. Said orientations and emplacements eliminated the excess-flesh “dog ears”, and thus required a smaller area of donor skin; resultantly, the broad-based, bilobed flap is less prone to the “trap door” and the “pin cushion” deformities common to skin-flap transposition procedure.

Surgical technique — the bilobed flap

The design of the bilobed flap co-ordinates its lobes with the long axis of the nasal defect (wound); each lobe of the flap is emplaced at a 45-degree angle to the axis. The two lobes of the bilobed flap rotate along an arc, of which all points are equidistant from the apex of the nasal defect.

• Based upon the available area of nasal skin, the surgeon selects the locale for the bilobed flap, and orients the pedicle. If the defect is in the lateral aspect of the nose, the pedicle is based medially. If the defect is at the nasal tip, or at the nasal dorsum, the pedicle is based laterally. An ideal location for the second flap is along the junction of the nasal dorsum and the lateral nasal wall.

• The nasal wound is cut and shaped into a teardrop form, by the cutting out of a Burrow’s triangle of flesh on the side of pedicle base. Cutting out the Burrow’s triangle (skin and subcutaneous fat) permits the moving the pedicle flap, to emplace it without buckling the tissues adjacent to the graft.

• Using a 20 mm calliper as a protractor — one tip at the apex of the wound — the surgeon delineates two semi-circles, an inner semi-circle, and an outer semi-circle. The outer semi-circle defines the necessary length of the two lobes of the skin flap. The inner semi-circle bisects the center of the original wound, and continues across the donor skin, establishing limit measure of the pedicle common to the two lobes of the flap. The surgeon then draws two lines from the apex of the wound; the first line drawn is at an angle of 45 degrees from the long axis of the wound, and the second line drawn is at a 90-degree angle from the axis of the wound. The two (2) lines delineate the central axes of the two lobes of the bilobed flap.

• The delineation of each of the two lobes of the flap begins and ends at the inner semi-circle, and extends to the outer semi-circle, to the point where it intersects its central axis. The width of the first lobe is approximately 2 mm narrower than the width of the wound; the width of the second lobe is approximately 2 mm narrower than the width of the first lobe.

• After the cutting from the tissue donor-site, the bilobed flap is elevated to a plane between the subcutaneous fat and the nasalis muscle. The wound is deepened, down to the nasal skeleton, to accommodate the tissue thickness of the bilobed flap. Technically, cutting the wound, enlarging it, is preferable, and safer, than trimming (thinning) the flap to fit the wound.

• Undermining the donor site for the second lobe allows closing it primarily; it also eliminates excess-skin “dog-ears” at the donor site. Moreover, if the donor site cannot be closed with sutures, or if the skin blanches (whitens) when sutured, usually because of excessively tight sutures, the tension is decreased by reducing the size (length, width, depth) of the wound with deep sutures that will allow it to heal more readily.

II. Nasolabial flap

In the nineteenth century, the surgical techniques of J.F. Dieffenbach (1792–1847) popularized the nasolabial flap for nasal reconstruction, for which it remains a foundational nose surgery procedure. The nasolabial flap can be either superiorly based or inferiorly based; of which the superiorly based flap is the more practical rhinoplastic application, because it has a more versatile arc of rotation, and the donor-site scar is inconspicuous. Depending upon the how the defect lay upon the nose, the flap pedicle-base can be incorporated either solely to the nasal reconstruction, or it can be divided into a second stage procedure. The blood supply for the flap pedicle are the transverse branches of the contralateral angular artery (the facial artery terminus parallel to the nose), and by a confluence of blood vessels from the angular artery and from the supraorbital artery in the medial canthus, (the angles formed by the meeting of the upper and lower eyelids). Therefore, the incisions for harvesting the nasolabial flap do not continue superiorly beyond the medial canthal tendon. The nasolabial flap is a random flap that is emplaced with the proximal (near) portion resting upon the lateral wall of the nose, and the distal (far) portion resting upon the cheek, which contains the main angular artery, and so is perfused with retrograde arterial flow.

Surgical technique — the nasolabial flap

The pedicle of the nasolabial flap rests upon the lateral nasal wall, and is transposed a maximum of 60 degrees, in order to avoid the “bridge effect” of a flap emplaced across the nasofacial angle.

• The surgeon designs the nasolabial flap and sets its central axis at a 45-degree angle from the (long) axis of the nasal dorsum. The shape of the skin flap is cut from the wound template fabricated by the surgeon.

• An incision is made to the flap (without an anaesthetic injection of epinephrine), which then is elevated and oriented, in an inferior-to-superior direction, between the subcutaneous fat and the muscle fascia.

• The cutting continues until the skin flap can be freely transposed upon the nasal defect. A Burrow’s triangle is excised from the skin between the medial border of the flap and the nasal dorsum; the triangle can be cut either before or after the elevation of the nasolabial.

• The flap then is bent back (reflected), and can be thinned (cut) under loupe magnification; however, a nasolabial flap cannot be thinned as easily as an axial skin-flap.

• After the nasolabial flap has been emplaced, the flap donor-site wound is sutured closed. For a wound of the lateral nasal wall that is less than 15 mm wide, the flap donor-site can be closed primarily, with sutures. For a wound wider than 15 mm — especially a wound that comprehends the alar lobule and the lateral wall of the nose — primary closure is not indicated, because such a wound closure imposes excessive stresses upon the skin flap, thereby risking either blanching (whitening) or distortion, or both. Such risks are avoided by advancing (moving) the skin of the cheek towards the nasofacial junction, where it is sutured to the deep tissues. Furthermore, a narrow wound, less than 1 mm wide can be allowed to heal by secondary intention (autonomous re-epithelialisation).

III. The paramedian forehead flap

The paramedian forehead flap is the premier autologous skin graft for the reconstruction of a nose, by replacing any of the aesthetic nasal subunits, especially regarding the problems of different tissue thickness and skin color. The forehead flap is an axial skin flap based upon the supraorbital artery (an ophthalmic artery branch) and the supratrochlear artery (an ophthalmic artery terminus), which can be thinned to the subdermal plexus in order to enhance the functional and aesthetic outcome of the nose. Restricted length is a practical application limit of the paramedian forehead flap, especially when the patient has a low frontal hairline. In such a patient, a small portion of scalp skin can be included to the flap, but it does have a different skin texture and does continue growing hair; such mismatching is avoided with the transverse emplacement of the flap along the hairline; yet that portion of the skin flap is random, and so risks a greater incidence of necrosis.

The paramedian forehead flap has two disadvantages, one operational and one aesthetic: Operationally, the reconstruction of a nose with a paramedian forehead flap is a two-stage surgical procedure, which might a problem for the patient whose health (surgical suitability) includes significant, secondary medical risks. Nonetheless, the second stage of the nasal reconstruction can be performed with the patient under local anaesthesia. Aesthetically, although the flap donor-site scar heals well, it is noticeable, and thus difficult to conceal, especially in men.

Surgical technique — the paramedian forehead flap

The surgeon designs the paramedian forehead flap from a custom-fabricated three-dimensional metal foil template derived from the measures of the nasal defect to be corrected. Using an ultrasonic scanner, the flap-pedicle is centre-aligned upon the Doppler signal of the supraorbital artery. Afterwards, the distal one-half of the flap is dissected and thinned to the subdermal plexus.

• The surgeon fabricates a metal foil template derived from the dimensions of the nasal wound.

• Applying a Doppler ultrasonic scanner, the surgeon identifies the axial pedicle of the tissue-flap (composed of the supraorbital artery and the supratrochlear artery), usually at the base, next to the medial brow; the point usually is between the midline and the supraorbital notch.

• Tracing the Doppler pulse of the blood flow of the supraorbital artery as far as possible, its delineation is continued as a vertical line, until it intersects with the hairline of the patient. The line extended from the pulse of the blood flow is the central axis of the forehead flap.

• The length of the flap is determined by placing an un-folded, un-stretched 4 x 4-inch gauze upon the wound, and with it measuring from the pedicle base to the distal (farthest) point of the wound. This measure is the length of the central axis of the skin flap.

• The template is rotated 180 degrees and placed over the distal (far) portion of the axis of the skin flap; the surgeon outlines it with a surgical marker. The outline markings are continued proximally and parallel to the central axis, maintaining a 2-cm width for the proximal flap.

• Without applying an injection of anaesthetic epinephrine, the flap is incised (cut), and the distal one-half is elevated between the frontalis muscle and the subcutaneous fat.

• At approximately the mid-portion of the forehead, the surgeon deepens the plane of the dissection down to the submuscular plane. The dissection continues toward the brow and the glabella (the smooth prominence between the eyebrows) until the skin flap is sufficiently mobile to allow its relaxed transposition upon the nose.

• Under loupe magnification, the distal portion of the forehead flap is de-fatted, down to the subdermal plexus. Yet, the fat-removal should be conservative, especially if the patient is either a tobacco smoker or a diabetic, or both, because such health factors negatively affect blood circulation and tissue perfusion, and thus the timely and correct healing of the surgical scars to the nose.

• The flap is allowed to perfuse, while the donor site is sutured closed by means of the wide undermining deep to the frontalis muscle. At that time, diluted epinephrine can be injected to the forehead skin, but not to the area(s) near the pedicle of the forehead flap. Moreover, if the distal wound is wider than 25 mm, it usually is not closed by primary intention, with sutures, but is allowed to heal by secondary intention, by re-epithelialisation.

• The forehead flap is attached to the nasal wound with subcutaneous sutures and skin sutures. If the excess tension of a suture compromises the color of the skin flap, the suture can be loosened, with a skin hook, and observed for 10–15 minutes; if the skin color remains compromised (white), the suture is removed.

• Upon the complete attachment of the paramedian forehead flap to the nose, the surgical wounds are dressed only with antibiotic ointment.

IV. Septal mucosal flap

The septal mucosal tissue flap is the indicated technique for correcting defects of the distal half of the nose, and for correcting almost every type of large defect of the mucosal lining of the nose. The septal mucosal tissue flap, which is an anteriorly based pedicle-graft supplied with blood by the septal branch of the superior labial artery. To perform such a nasal correction, the entire septal mucoperichondrium can be harvested.

Surgical technique — the septal mucosal flap

The surgeon cuts the anteriorly based septal mucosal tissue-flap as widely as possible, and then releases it with a low, posterior back-cut; but only as required to allow the rotation of the tissue-flap into the nasal wound.

• The surgeon measures the dimensions (length, width, depth) of the nasal wound, and then delineates them upon the nasal septum, and, if possible, incorporates an additional margin of 3–5 mm of width to the wound measurements; furthermore, the base of the mucosal tissue flap should be at least 1.5-cm wide.

• The surgeon then makes two (2) parallel incisions along the floor and the roof of the nasal septum; the incisions converge anteriorly, towards the front of the nasal spine.

• Using an elevator, the flap is dissected in a sub-mucoperichondrial plane. The (far) distal edge of the flap is cut with a right-angle Beaver blade, and then is transposed into the wound. The exposed cartilages will reepithelialise (regenerate the epithelium), provided the opposite (contralateral) side of the septal mucosa is undisturbed.

A technical variant of the septal mucosal flap technique is the Trap-door flap, which is used to reconstruct one side of the upper half of the nasal lining. It is emplaced in the contralateral nasal cavity, as a superiorly based septal mucosal flap of rectangular shape, like that of a “trap-door”. This septomucosal flap variant is a random flap with its pedicle based at the junction of the septum and the lateral nasal skeleton. The surgeon elevates the flap of septal mucosa to the roof of the nasal septum, and then traverses it into the contralateral (opposite) nasal cavity through a slit made by removing a small, narrow portion of the dorsal roof of the septum. Afterwards, the septomucosal flap is stretched across the wound in the mucosal lining of the lateral nose.