Ultrasonic Bone Shaping Technology in Rhinoplasty (Piezo)
3 December 2019 onur
Sound waves are intensified via a crystal interface and directed at the bone, leading to a controlled degradation of the mineralized layer and type 1 collagen structure in the bone. This forms the basis of ultrasonic bone cutting technology and is called the “piezo” effect. The procedures you may have heard about under different names such as ultrasonic rhinoplasty, ultrasonic bone cutting and piezo all refer to the same scientific procedure.
We can say that this technology has had the greatest global impact in the field of rhinoplasty.
Here is the short story, advantages and disadvantages of the “piezo” technology, which is on everyone’s lips at all international meetings.
When rhinoplasty was first discovered 100 years ago, it was an almost completely closed surgical procedure. Surgical techniques were applied through the nostrils without a chance of seeing the anatomy of the nose, and the aim was not to correct the anatomy of the nose, but to change its shape. In his earlier operations, Joseph, the father of rhinoplasty and also an orthopedist, used to break the nasal bones by hitting them with a hammer over the skin and shape them later. Such breaking of the bones caused unwanted deformities as well as a failure of the fracture lines to pass through the desired points. Over the years, Joseph invented many hand pieces that were used to cut, break and shape the nasal bones. These mainly included saws, files, chisels, bone shears and hammers. Interestingly, over the next 100 years, more or less the same tools were used to shape bone structures in rhinoplasty. Naturally, more elegant, more diverse and more anatomical instruments were designed, but the essential principle did not change.
Don’t get me wrong: Michelangelo sculpted the statue of David with much more primitive tools, and in the hands of an experienced surgeon, these classical metal instruments can be used to shape nasal bones very smoothly and precisely.
I mean, in most patients.
This is because each person’s bone anatomy is quite different from another person’s. Nasal bones may be thicker in some places and thinner in others. Similarly, curvatures in the nasal bones may manifest themselves in very complex and asymmetrical geometries. Moreover, it is extremely difficult to use classical techniques to see and shape the bones in the posterior/deep parts of the nasal bone roof.
Consequently, even in the hands of the world’s most experienced surgeon, the rate of having issues related to the bone roof is around 10-15%. Until a few years ago, we could manage this situation, saying that nobody’s perfect, that such a level of irregularity was normal after rhinoplasty. Today, rhinoplasty surgeons are doing so well that expectations have risen tremendously. Imperfections that were considered normal in the past are today perceived as the next step to overcome on the road to perfection.
Right at this point, we can say that piezo came to the rescue.
In order to shape bones with piezo, it is first necessary to isolate the bones from the skin and expose them. We call this approach the ‘wide dissection of the roof’. Wide dissection of the roof was a taboo in rhinoplasty. That is because we were afraid that when we isolated the bone from the skin, the blood circulation in the bones would be impaired, resulting in bone loss. This fear is not unfounded, because when you isolate the bone from the skin, the vitality of the bone becomes dependent only on the mucous layer to which it is attached on the inner surface. And if the bone shaping technique you employ damages the mucosa, e.g. it cuts, burns or pierces the mucosa, it is possible to face catastrophic results. The piezo technology makes it possible to shape bones through a wide dissection, as it does not damage this tissue behind the bone while cutting it.
Piezo allows the surgeon to work very precisely. It goes without saying that some maneuvers you can do with piezo cannot be performed with standard hand pieces and instruments. Again, when piezo is used, it is possible to exert great precision to create the controlled fracture lines in the bone. In some surgeries where a chisel and a hammer are used, the bone may break where it is structurally weakest rather than where the surgeon wants it to break, and it can be highly challenging to correct that later. Another advantage of piezo is that since we see the entire bone roof as we work, it facilitates the recognition of surface irregularities and asymmetries caused by the bone shape and the correction of such irregularities and asymmetries with case-specific incision designs.
On the other hand, we are still not talking about a magic wand here, but rather a hand instrument.
The impact the instrument will bring still depends on the hand holding the instrument, the eyes seeing it and the brain designing it.
It is also possible to create horrifying noses with piezo.
The piezo technique has some disadvantages of its own.
Wide dissection may lead to blood and fluid deposition between bones and skin after surgery as well as prolonged edema, bruising and infections. Therefore, we have to place microdrains which we do not use in normal surgeries. Secondly, although it is said to be not harmful to soft tissues, the upper layer of the skin rich in type 1 collagen is an exception. The contact of the piezo tip with the skin may cause abrasions and burns on the skin.
Another issue is that when we isolate the bone from the skin, we deactivate one of the support structures that hold the bone in place, and when the incisions are completed, the bones exposed are sometimes highly mobile, i.e. unstable. In that case, it may be required to use various suturing techniques to keep the bones in place.
My advice to candidates for rhinoplasty is not to seek surgical options imposing the use of piezo as a prerequisite. I am telling this as a surgeon who performs all nose surgeries using ultrasonic bone cutting technology. The surgeon’s knowledge, skill and experience are way more important than what instrument is used. The literature currently has no studies proving that the aesthetic and functional results obtained with piezo are superior to standard techniques. Furthermore, there is no consensus that ultrasonic bone cutting technology is the gold standard.
To sum up, the key to the ideal result in rhinoplasty is still not plugged into the socket, but in the hands of the surgeon.
Take good care…