One of the smallest areas of facial augmentation by bony surface area is the pyriform aperture region of the midface. The lower base of the nose is divided into two zones, paranasal and premaxillary. Both areas provide support to the base of the nose but with different effects. The paranasal region builds up the base of the nostrils underneath the alar-facial junction. It can also help soften the deepest of the upper nasolabial fold. Conversely premaxillary augmentation has a central effect pushing out the anterior nasal spine area underneath the columella. Often done together premaxillary and paranasal implants create a lower central midface augmentation effect.
Off-the-shelf implants have been available for pyriform aperture augmentation for decades made of either silicone and Medpor materials. But my current preference are paranasal and premaxillary implants made of ePTFE material. Their microporous surface allows for some tissue ingrowth and screw fixation is not needed. They are also easily modifiable by a variety of instruments to help adapt their shape to the bone.
One of the unique features of paranasal implant augmentation is that the bony area onto which it is placed is not convex or flat. Rather the pyriform aperture rim is concave in shape. Extending out from the pyriform aperture laterally is the deeper concavity of the canine fossa which makes up much of the maxilla below the infraorbital nerve foramen. This is why in many paranasal implant patients the augmentation can have a bump-like effect or feel as its outer shape is unnaturally convex.
The ePTFE paranasal implant material has the ability to be easily reshaped so that it has a more natural slope to its outer surface onto the maxilla. While it can be shaved down on its perimeter with a scalpel another method is instrument compression. Using a needle holder or large clamp the implant material is compressed along its edges so that the transition onto the bone is very smooth. By the method by which ePTFE is made and its microporous structure it can be compressed without rebound.
The largest patient complaint about paranasal implants is that they can feel unnatural with a bump-like effect. Some patients feel that their smoke is affected as the upper lip pulls up against the implant. Many of these historic complaints have been because the implants where placed into the soft tissues of the nasal base, often done at the time of a rhinoplasty. Many of these concerns have been obviated by implant placement onto the bone in the subperiosteal location. Making sure the implant transition is smooth and non-palpable is another step in eliminating a paranasal contour deformity.
Dr. Barry Eppley
World-Renowned Plastic Surgeon