Nasal Implants 

Nasal implants are used in nasal reconstruction for aesthetic deformities or nasal obstruction due to structural nasal collapse or volume loss caused by trauma (including previous surgery), autoimmune disease, neoplasm, or infection.

Category

Nasal implants

Device details

Autologous materials

• Cartilage (septal, conchal, costal)
• Bone (iliac crest, calvaria)
• Soft tissue

Alloplasts

The products listed below are just a few of the many available.

Implantech

• Voloshin Dorsal Columella (dorsal nasal implant, silicone rubber)

Gore & Associates

• Gore-Tex (expanded polytetrafluoroethylene [e-PTFE] sheets)

Porex Surgical

• Medpor® nasal dorsal implants (porous high-density polyethylene [PHDPE])
• Composite e-PTFE/silicone

Structural nasal collapse or volume loss due to trauma (including previous surgery), autoimmune disease, neoplasm, or infection can lead to aesthetic deformity or nasal obstruction, necessitating nasal reconstruction. Nasal reconstruction presents a significant challenge to the facial plastic surgeon, in which the dual goals are reestablishment of the desired aesthetic nasal contour and restoration of respiratory function.

Over the past 40 years, many materials have reportedly been used for nasal augmentation. By far, the most common has been silicone rubber. However, the lack of incorporation of silicone into the surrounding tissues translates into significant drawbacks to its use, most notably a high potential for extrusion, inability to provide structural support, and lack of utility in thin-skinned areas; thus, the search for the ideal nasal implant still continues.

Accordingly, the use of implantable materials, which vary from autologous materials such as septal cartilage to synthetic implants such as expanded polytetrafluoroethylene (e-PTFE) (Gore-Tex, WL Gore & Associates) and porous high-density polyethylene (PHDPE) (Medpor, Porex Surgical) is discussed in this article.

See also Gore-Tex Soft-Tissue Implants and High-Density Porous Polyethylene (Medpor) Soft-Tissue Implants.

Technical considerations

The technique of nasal reconstruction has undergone a slow transformation from simple skin coverage of gross midfacial tissue defects to aesthetic contouring to, finally, the dual goals of functional and aesthetic reconstruction. Both autologous materials and alloplasts are used for this purpose and are discussed further below.

Enough progress has been made in the understanding of implant physiology to facilitate a rational decision regarding implant use when adequate autologous tissue is unavailable. Although autogenous tissue is still by far the preferred material for nasal augmentation, it is no longer acceptable to maintain that alloplasts should never be used in the nose. Patients requiring significant nasal augmentation, as well as those in whom sufficient autologous tissue of acceptable quality is unavailable, should be considered candidates for alloplast augmentation.

Further refinements in the form, texture, microstructure, and chemical composition of these implants will improve the short-term and long-term cosmetic and functional results of nasal reconstruction using alloplasts.

The platyrrhine nose may require nasal dorsal and tip augmentation, as well as a thin columella strut and small particle premaxillary plumper implants. Overresected noses generally require reconstruction with bilateral thin, curved nasal battens, as well as a short, thin columella strut, small particle plumper implants, and a nasal dorsal implant without tip augmentation.

Of course, each nose is different, and the choice of specific techniques for individual patients depends on the specific problems encountered and the desired outcome of the patient. The external rhinoplasty approach is generally the procedure of choice when undertaking these types of nasal reconstruction. This approach helps avoid contamination of the implant with bacteria colonizing the nasal mucosa. It also allows exact suture placement when necessary.

Before placement, all implants are soaked in an antibiotic solution, and antibiotics are administered intravenously at the start of every surgical procedure.

Autologous materials

Autologous materials are preferred for nasal augmentation when they are available in sufficient quantity and quality.^[1] They include cartilage, bone, and soft tissue.

Septal, conchal, and costal cartilageimplants

Septal cartilage is the criterion standard material for nasal augmentation. It is quickly harvested in the same operative field and has no risk of disease transmission, rejection, or toxicity. However, previous surgery or trauma may limit its availability and thereby preclude its use.

Another option is conchal cartilage, which leaves little or no cosmetic defect at the donor site when harvested. However, it may be brittle and difficult to sculpt. In addition, conchal cartilage may be insufficient when significant augmentation is needed, and it requires a separate operative site. The inherent curvature of conchal cartilage may increase the potential for postoperative warping. Irradiated rib cartilage has been advocated, but long-term persistence is controversial, especially when used for structural support.^[2]

Large amounts of donor cartilage can be provided by costal cartilage. Drawbacks include a chest scar, risk of pneumothorax, and possible warping of the graft.

Boneimplants

Bone options include the iliac crest and calvaria. The iliac crest provides flat bone for dorsal augmentation. However, it carries a significant risk of morbidity from its harvesting. In addition, embryologically, the iliac crest is endochondral bone and therefore may undergo resorption. Calvarial bone is the preferred bone for nasal augmentation. It has less postoperative morbidity and is closer to the operative field.

Because membranous bone undergoes less resorption, it is more suitable for use as a graft. The drawback is the possible risk of dural or cerebral injury from the harvesting. The risk of this complication is lessened by harvesting only the outer table and leaving the inner table intact. Postoperative donor site morbidity can be lessened by saucerizing the defect edges, filling the defect with bone cements, or both.

Soft-tissueimplants

Potential soft-tissue implants include fascia and dermis. Both require a separate incision, and neither can provide large amounts of skeletal augmentation. In addition, neither provides structural support.

Alloplasts for nasal augmentation

Alloplasts are increasingly being used for nasal augmentation.^{[3, 4, 5]} They include silicone rubber, expanded polytetrafluoroethylene (e-PTFE), and porous high-density polyethylene (PHDPE) implants.

Silicone rubberimplants

Silicone rubber has been used for many years, with varying reports of success. Although it is easy to place, extrusion rates of 24-55% have been reported. A thin fibrous capsule surrounds it, with mild chronic foreign body reaction for the lifetime of the implant. Silicone rubber is poorly tolerated in thin-skinned areas and in revision cases. However, good results have been seen in Asian patients, possibly as a result of differences in skin thickness.

Expanded polytetrafluoroethyleneimplants

e-PTFE is a microporous woven polymer made up of PTFE fibrils. The small pore size (22 µm) limits host tissue ingrowth to the periphery. e-PTFE is usually well tolerated, with a less than 2% risk of infection, and it is found to be useful for volume enhancement of the nasal dorsum, glabella, and subnasale. However, this type of implant may not provide sufficient structural support in all cases. Preformed e-PTFE implants are no longer manufactured, but e-PTFE sheets can be layered and shaped for dorsal augmentation.

Porous high-density polyethylene

PHDPE has internal pores of 100-250 µm that promote soft-tissue and bony ingrowth, lending mechanical stability to the implant in its bed (see the images below).

PHDPE is provided in a number of shapes designed for the nose and other facial areas. It is easy to sculpt and can be molded by immersing it in hot water. Tissue ingrowth provides an avenue for cellular immune response, thereby imparting resistance and tolerance to exposure not seen with other alloplast implants. Disadvantages include its inability to be resterilized and the need for wide undermining because of its more rigid character.

Composite e-PTFE/silicone

Composite implants with a central solid silicone core coated with a thin layer of e-PTFE have become commercially available. Currently, these are available for either dorsal augmentation or combined columellar support and dorsal augmentation. Although composite implants are easy to use and may add additional qualities to e-PTFE implants (especially sufficient rigidity to increase tip support), long-term follow-up is needed to determine if the coating of e-PTFE is sufficient to eliminate the risk of implant extrusion.

The most common site at which nasal augmentation is required is the dorsum. Previous surgery, trauma, and a congenitally low dorsum all necessitate correction with dorsal augmentation. The incompetent nasal valve can cause nasal obstruction, and functional rehabilitation requires reconstruction with a semirigid implant. Volume augmentation is often required to increase an acute nasolabial angle.

The overresected nose represents the stereotypical surgical nose. These patients commonly report nasal obstruction resulting from incompetent nasal valves. The tip may or may not be overrotated, and the dorsum is typically too low.

Noses that have experienced trauma most closely resemble the traditional saddle nose (see the image below) and usually have a widened dorsum in addition to loss of dorsal height.

Contraindications

Reconstruction with any material in the context of an autoimmune or infectious process is unlikely to yield satisfactory results. Likewise, patients who habitually use cocaine are advised to seek treatment of the addiction before any attempts at reconstruction. Previous surgery compromises the skin/soft tissue envelope, increasing the risk of implant-related complications.

Expected results

Reported results of silicone nasal implants vary widely and are clearly related to local factors, such as previous surgery, intercurrent vascular disease, or technique.^[6] Although some authors have reported successful use of silicone nasal implants, others have reported extrusion rates of 30% or higher, most notably when the implants were used for structural support in compromised skin/soft-tissue envelopes.

In contrast, expanded polytetrafluoroethylene (e-PTFE) implants appear to be well tolerated in the nose. Conrad and Gillman reported a 97.3% long-term success rate with these implants.^{[7, 8]}

Long-term follow-up of composite silicone and e-PTFE implants is necessary to make definitive conclusions, but the author's personal experience over the past 2 years has been favorable.

Upon review of a group of 187 cases of functional and aesthetic nasal reconstruction using multiple PHDPE implants, Romo et al reported only 6 implants were removed.^[9] One implant was removed, reduced in size, and reimplanted because of excessive augmentation. A second implant was removed 3 months postoperatively after the patient developed nasal cellulitis that did not respond to intravenous antibiotics. In a third patient with cocaine-induced septal perforation and saddle-nose deformity, removal of a dorsal implant was necessary following a blistering sunburn and subsequent infection.^[9] Three alar-batten implants were removed because of infection.

The skin/soft-tissue envelopes in these patients who developed cellulitis had been traumatized by ischemic changes from postoperative edema in an unpacked nose, heavy tobacco use, and/or multiple previous surgeries.^[9]

A thorough preoperative discussion with the patient about the nature of the implant is mandatory. Patients must be informed of their specific needs for surgery, and various autologous, homologous, and synthetic options should be outlined. Patients must also be fully informed regarding the relative merits and risks of each material, and they must give an unrestricted informed consent before any procedure.

Anatomic considerations

Three basic scenarios are commonly encountered in which augmentation is needed: the patient with a platyrrhine nose and the patient with an overresected nose.

The saddle-nose deformity is one of the more common deformities for which major nasal augmentation is performed. The most common etiologies of the saddle-nose deformity include trauma, previous nasal surgery, and cocaine abuse. Less common etiologies include Wegener granulomatosis, sarcoidosis, relapsing polychondritis, and Hansen disease (leprosy). See also Saddle Nose Rhinoplasty.

The patient with a platyrrhine nose presents with a low wide dorsum, poor tip projection, and acute nasolabial angle.

The nose that has been overresected during previous surgery typically demonstrates a scooped-out dorsum. Aggressive techniques at the nasal tip often lead to scarred lower lateral crura with a resultant pinched appearance. The loss of integrity of the tip cartilage also leads to nasal obstruction due to nasal valve collapse.

Posttraumatic deformities are usually limited to poor projection of the nasal dorsum. Asian and black patients demonstrate an acute nasolabial angle, a poorly defined and underprojected nasal tip, and a low dorsum.

Oral antibiotics are administered postoperatively for 7-10 days. Patients are instructed to refrain from any activity that may reduce blood flow to the nose, including tobacco use.

Long-term monitoring

Longer-term follow-up is necessary to determine the actual success rate of these implants through the lifetime of the patient. Minimizing trauma and attention to sterile technique are essential to the success of any implant.

Although the synthetic implants used in current practice have been well studied and are more accepted than ever before, they have some limitations that must be considered.

Infection may occur by 2 distinct routes: (1) direct inoculation (eg, placement of an implant through a contaminated area) and (2) hematogenous spread. Infection occurs in 2-3% of patients with porous high-density polyethylene (PHDPE) and expanded polytetrafluoroethylene (e-PTFE) nasal implants and frequently necessitates early implant removal.

Extrusion of the implant is less likely after adequate tissue ingrowth into a porous implant, but it is more likely to occur in solid rigid implants. Shifting of the implant is also more likely in implants with limited fibrovascular ingrowth.