Dorsal preservation rhinoplasty requires precise management of the osseocartilaginous vault. Ultrasonic piezo instruments offer several advantages compared with traditional tools such as hand saws, rasps, and osteotomes. As always, an understanding of the dynamics of manipulation of the vault, anatomy, and proper technique are paramount and are reviewed herein.
The primary methods of bony vault manipulation in preservation rhinoplasty are the let-down and push-down, with the former being preferred for airway preservation.
The piezo device, with tips such as saws, rasps, and scrapers, allows for precise management of the osseocartilaginous vault.
The drill tip allows for safe perforation of mobile nasal bones or the nasal spine.
Piezoelectrical instruments (PEI) have been used for a long time in maxillofacial surgery and dentistry. These devices are useful in cutting through hard tissues such as bones and have the advantage of minimizing damage to soft tissues and reducing bleeding during the bone shaping process. Thanks to the new generation of the devices, procedures such as reshaping, cutting through and rasping of the nasal bones can be carried out much faster and easier. There are visibly less bruises on the skin in the postoperative period. Moreover, because this technique helps to avoid the unwanted fracture lines that may occur with traditional osteotomies carried out with osteotomes, it may help prevent typical complications during the reshaping of the bones. An excellent resource on this is Dr Gerbault’s publication on piezo surgery.
Piezo-osteotomy and piezo-ostectomy
There are different ways to perform septal resections in dorsal preservation techniques. High septal, mid septal, and low septal strip modifications all need precise cuts on the perpendicular plate of the ethmoid bone and removal of a piece of the cartilage and bone. The long saw insert of the piezo device is extremely useful to make a sharply defined cut on this thin layer of the bone without creating any additional fracture lines. We recommend making all excisions from the septum incrementally to decrease the risk of step-offs at the rhinion. If more lowering is required, we can incrementally excise small strips and recheck until the desired dorsal height is achieved. The piezo long saw insert allows us to make this step by step lowering safely ( Fig. 1 ).
Especially in dorsal preservation techniques, the amount of lowering of the dorsum depends on the osteotomies and overlapping area of the low-to-low osteotomy sides ( Fig. 2 ). As a result of this, precise osteotomies are more important and necessary in dorsal preservation. To prevent a visible or palpable step deformity in the lateral osteotomy area, we perform our osteotomies as close as possible to the maxillary bone, right above the nasofacial groove in a low-to-low approach.
Depending on the ligament preservation technique used, different dissection approaches can be used for the osteotomies. If the skin attachments to the dorsum are to be preserved, we can create the tunnels on the frontal process of the maxillary bone posterior to the nasomaxillary suture line ligament. It is possible to use piezo instruments in a closed approach with this technique ( Fig. 3 ).
Given the closed space when using endonasal methods and preserving the dorsal skin attachments, the heat generated from piezo instruments can be harmful to the skin and thus precludes their use in transverse osteotomies. Thus, we use the combination of hand saws and a 2-mm external osteotome for transverse and radix osteotomies in this group ( Fig. 4 ). When we use an extended open approach, the piezo instruments can be used for all the osteotomies.
The most common complication of dorsal preservation rhinoplasty is a residual hump. One of the most important reasons is resistance to movement of bone in the low-to-low osteotomy area. In traditional techniques, lateral osteotomies are needed for closing the open roof and narrowing the nasal pyramid’s base. The direction of the osteotomes was horizontal to the maxillary bone to reduce posterior displacement of the nasal bones. As reviewed elsewhere, there are 2 different ways to handle the bony vault in dorsal preservation, the let down and the push down. When we remove a strip of the bone on the facial groove, we call it let down. If we do osteotomies and overlap the bones, it is called a push down. Usually, we do the combination of these 2 procedures. In the cephalic portion of the bony pyramid, an osteotomy (without ostectomy) is performed, and is thus a push-down type of maneuver. In the caudal portion of the nasal bony pyramid (Webster triangle), an ostectomy is performed, thus creating a let down. In the push-down maneuver, the horizontal osteotomy creates resistance to posterior displacement, and thus the surgeon has to squeeze the nasal bony pyramid to force it to descend medial to the pyriform aperture. An advantage of PEI is that it is possible to change the direction of the bony cuts from horizontal to sagittal, decreasing this resistance to posterior displacement.
As the lateral osteotomy is performed in the sagittal plane, it is possible to easily push in the nasal dorsum, in both osteotomies and ostectomies, because the borders of the new bones are parallel to the sagittal plane ( Fig. 5 ). It enables the dorsum to move lower and decreases the risk of a residual hump or recurrence of the hump in the late postoperative period.
Dorsal preservation is also a useful method to correct the crooked nose. The method chosen by the surgeon for correction of deviations depends on the pathology of the septum. For example, a low septal strip can be more useful for crooked nose correction. When it comes to designing osteotomies for correction of bony vault deviations, asymmetric osteotomies should be considered for correction of the unequal sides. The direction of the osteotomies again becomes important: a horizontal lateral osteotomy is performed on the shorter side to decrease posterior movement and a sagittal osteotomy is performed on the longer nasal bone to allow posterior movement and correction of the crooked pyramid ( Fig. 6 ).