Premaxillary Augmentation Rhinoplasty Treatment & Management

Premaxillary augmentation may be achieved with surgical implants. Many implants are approved for use in nasal reconstruction; these may be classified as autografts, homografts, and alloplasts. However, no ideal implant currently exists.

Autografts are derived from the patient's own body and include bone (rib, iliac crest, septal, calvarial) and cartilage (septal, conchal, rib). Homografts are obtained from another human donor and include irradiated cadaveric rib and dermis (AlloDerm). Alloplasts are semisynthetic or synthetic materials; examples include silicone, Gore-Tex or polytetrafluoroethylene (PTFE), hydroxyapatite, and titanium. ^[5]

Autografts

Many plastic surgeons consider autografts the preferred implant material because of their biocompatibility and low infection and extrusion rates. However, disadvantages should be mentioned, including donor site morbidity, need for additional operative time, limited supply, and the potential for resorption. In the premaxilla, the 2 main autologous graft materials used are cartilage and bone.

Cartilage may be harvested from the septum, which is stronger and straighter than conchal cartilage. These attributes make septal cartilage easier to carve and shape. Alternatively, the concha yields approximately 5 cm of cartilage for grafting and may be particularly useful for onlay grafts to the alae, which have a similar curvature. Conchal cartilage should be harvested from the more pronounced ear (because excessive conchal removal may medialize the ear somewhat), from the ear that is not used on the telephone, or from the ear that the patient does not sleep on at night. Costal cartilage, usually taken from the fifth, sixth, or seventh rib, may also be used. Harvesting costal cartilage should be avoided in the elderly population because the cartilage is most likely calcified, making carving almost impossible. Harvesting rib cartilage has several distinct disadvantages: (1) higher resorption rate, (2) risk of pneumothorax, and (3) postoperative pain.

Bone may also be used to reconstruct nasal defects. Split calvarial bone grafts of membranous bone origin may be less likely to resorb than iliac crest grafts of endochondral bone. In addition, removal of iliac crest may cause more postoperative pain. Costal bone may also be used for nasal reconstruction. The main drawbacks of bone grafts are the higher resorption rate, difficulty shaping the graft, and malposition over time.

Homografts

Homografts are used less frequently than autografts and are associated with a higher rate of resorption. Acellular dermis (AlloDerm) has been used successfully as a camouflaging and soft tissue contouring material, which is especially helpful in thin-skinned individuals, and it may be combined with cartilage or rib grafts. However, it also may resorb over time.

Allografts

An advantage of allografts is their "off-the-shelf" availability. No additional operative time is required for graft harvest, and no donor site morbidity occurs. A disadvantage is the risk of infection and extrusion that may occur at any time during the patient's life.

Synthetic implants have different properties that are important in tissue reactivity and bio-integration. Porosity allows tissue ingrowth but also bacterial entry, which can be countered by macrophage ingress if the pore size exceeds 50 µm. If pore size is greater than 100 µm, then bony and fibrous ingrowth may occur to increase graft stability. For example, Medpor has pores ranging from 100-250 µm, which allows for significant tissue ingrowth. Some implants that lack pores, such as solid silicone, prevent tissue ingrowth and bacterial entry. By virtue of silicone's nonporous nature, the infection rate is lower compared to other allografts, and stabilization is achieved via capsule formation. If the capsule becomes thick, the surrounding tissues may be adversely deformed. Silicone is also relatively inert and biocompatible by virtue of its close proximity to carbon on the periodic table.

Polymer implants

Polymers are composed of a long chain of repeating subunits. The length of chains and the amount of cross-linking of branches directly influence the stability of the polymer, an important property for implant materials. Commonly used polymers are silicone, Gore-Tex or PTFE, and Medpor. Surgical-grade silicone is composed of a methylated silicone polymer. It may come as a liquid gel or as a solid rubber. The latter is used in nasal reconstruction and is particularly useful in premaxillary augmentation. As mentioned, silicone is nonporous and hence does not permit tissue ingrowth. Gore-Tex is a polymer of fluorine and carbon with small pores (22 µm); Gore-Tex permits some limited tissue ingrowth for increased stability and has been accepted in a wide variety of uses in rhinoplasty. Medpor, a high-density polyethylene polymer, has large pore size (100-250 µm) and is very rigid.

Ceramic implants

Hydroxyapatite is the principal member of this group of implants and has been used in rhinoplasty, including premaxillary augmentation. Hydroxyapatite granules (Interpore 200) form an adherent paste that may be inserted adjacent to hard tissue but should not be used in a soft tissue pocket. Hydroxyapatite also does not resist compression and should not be considered a rigid supportive element.

Metallic implants

Metallic implants are rarely used in nasal reconstruction but are mentioned for completeness. Metallic implants may be classified into those that osseointegrate with adjacent bone to form a molecular bond (eg, titanium) and those that instead form a capsule, which in turn may impair stability.

Insertion of implants

Many different implants are available for nasal reconstruction. These implants may be placed strategically into various anatomic sites to achieve different cosmetic goals. Implants may be placed between the anterior maxillary spine and the posterior end of the medial crura as a plumping graft to enhance nasal projection and to improve the nasolabial angle. Alternatively, a columellar strut may be inserted to increase projection, provide more structural support, and possibly alter the columellar-alar relationship. ^[6] The surgeon should take care not to make the strut too long; it should end just above the nasal spine. Otherwise, it may shift to the side, leading to nasal deviation and even a clicking sensation that the patient may find disconcerting.

If the entire maxillary segment between the nose and the upper lip is retrusive, a larger block may be inserted for augmentation. This should, in turn, favorably alter nasal appearance. These implants may be inserted via many different incisions. For example, a plumping graft may be inserted via an intranasal incision, external rhinoplasty incision, or sublabial incision. A larger maxillary implant may be inserted through an extended subnasal or sublabial incision.

Rotational flaps

Rotational flaps have been used less frequently for premaxillary augmentation. Adamson and McGraw describe separating the intracrural soft tissue from the medial crura through an open rhinoplasty incision (see the image below). The posteriorly based flap of intracrural tissue is then bunched up in front of the maxillary spine to achieve 3 mm of added projection. The authors report no resorption in 7 patients who underwent this technique over a 3-year period. However, they caution that this flap does not add significant projection and may be used in conjunction with other methods of augmentation.

Flowers and Smith advocate marking out an area immediately inferior to the nasal base along the upper lip as the donor site for the premaxillary augmentation (see the image below). This flap is raised with its base medially located, de-epithelialized, and pulled through anteriorly within a columellar pocket. They contend that this particularly benefits elderly individuals because the upper lip is shortened as the nasolabial angle is increased.

Orthognathic surgery

As an alternative to a maxillary implant for a retruded premaxilla, a Le Fort I osteotomy may be performed to address both the retruded premaxilla and malocclusion, if this condition exists. Advancing the entire maxilla may variably affect nasal appearance. Poor et al reported that 50% of patients undergoing Le Fort I advancement perceived worsening of nasal appearance after surgery. Unlike a plumping graft, which advances the columella and not the alae (see the image below), advancement of the whole maxilla pushes the entire nasal base forward, which may cause the alae to widen and the nasolabial angle to become more acute. Patients who undergo maxillary orthognathic surgery may require rhinoplasty.

See Contraindications.

Techniques for premaxillary augmentation are part of the arsenal of the facial plastic and reconstructive surgeon. The tip-lip complex is a critical part of every rhinoplasty analysis and deserves special consideration in patients who are aging, those with congenitally malformed noses, and patients of specific ethnic descent (see Pathophysiology).

Implants remain a mainstay for premaxillary augmentation, and the surgeon must carefully weigh the advantages and disadvantages of the type of implant selected. Premaxillary implants serve to address several deformities at once: an acute nasolabial angle, underprojected nose, and short upper lip. If the entire upper lip is underdeveloped, a large implant or orthognathic surgery may be required to correct both nasal and premaxillary deficiencies. The facial plastic surgeon must use aesthetic judgment to decide the need for surgical intervention in this anatomic region critical to overall nasal and facial cosmesis. ^[7]