#5-3. HIFU Face Lifting

Side effects of HIFU

I apply a motorized vibrator on the chin or cheekbone. As with Thermage CPT, this method is based on the gate control theory where the neural transmission to the brain is blocked to reduce the sensation of pain. Even if the area where the vibrator is applied is far away from the treatment area, the effect is carried by bone conduction. I find this method very satisfying.

HIFU has a few disadvantages. HIFU’s effect relies on powerful thermal action but its non-selective destruction of tissues entail various problems. I experienced various complications in my early days with HIFU as the data was hard to come by. In short, it could be described as a high-risk, high-return method.

Less than optimal contact with the skin caused small skin ulcer or irradiation reaching the temporal region leading to extensive subcutaneous bleeding. Temporary sensory loss of the head due to supraorbital nerve damage is a dreaded complication. The biggest problem is the loss of sensation of the upper lip likely caused by infraorbital nerve damage. This causes discomfort in daily activities such as teeth-brushing, etc. and can last for up to 3-4 weeks in some cases. Avoiding the course of the innervation can prevent nerve damage, however, loss of sensation still occurs in rare cases. Immobilization of the anguli oris can also occasionally occur. At first, I thought it was the marginal mandibular branch damage but rather than typical symptoms of marginal mandibular branch damage, limited lateral mobility of the mouth corner and poor coordination of the upper and lower lips leading to distorted mouth shape are more prevalent. Such symptoms still occurs even when the course of the marginal mandibular branch is avoided during irradiation. As such, I suspect the cause is inflammation and fibrosis due to damaged M. risorius or M. zygomaticus major.

In fact, cases of these complications often present severe edema or pain in the affected areas immediately after treatment. It is important to distinguish treatment plans for marginal mandibular branch damage and direct damage of these muscle groups once complications manifest. HIFU can effectively destroy tissues with heat and without correct understanding of facial anatomy, unexpected and severe complications can occur.

Another challenge with HIFU is the unclear target area. When targeting the SMAS in the depth of 4.5mm, one has to understand that the SMAS does not spread throughout the cheek. Weaker medial sides or retaining ligaments cannot be lifted regardless of strength or frequency of the treatment. Additionally, the SMAS covers the facial expression muscles and severe damage can cause motor disturbance. Especially when targeting deeper areas, close evaluation of the area is necessary. Irradiation over fat tissues result in only a weak lifting effect. Therefore, it seems better to irradiate areas with more pulling power.

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Combination of HIFU with other treatment modalities

As already mentioned, the biggest disadvantage of the HIFU device is the pain aspect which Japanese patients are particularly averse to. This is why the HIFU device is not widely distributed in Japan but as it has long been in clinical use in other fields, abundant data, both positive and negative, are available. To make up for the negative clinical experiences with the device, combination with other modalities are being tried.

The earliest effort in this regard was combining HIFU with Thermage. Skin elasticity is improved with Thermage and the SMAS and deep fascia structure are buttressed with HIFU. This seems to bring better lifting effect than using HIFU on multiple layers. Thermage has excellent tightening effect. As both devices are used on the same day, lower dermis can severely damaged. Using a 3.0mm transducer in the cheek area or using weaker HIFU output in shallower layers can help reduce damage.

Combinations with a filler and biological suture threads can be also considered. HIFU can be limited to the SMAS or neck for supplementary benefit. With a more focused and smaller treatment area, cost is reduced bringing higher patient satisfaction.

Currently, extensive research is being done on the antomical mechanism of facial aging. Sagging skin and subcutaneous fat as well as atrophy and drooping of superficial fat compartment, and deep cheek fat pad are being studied. Currently, HIFU brings the most powerful lifting effect among lifting devices. This, however, is not enough. Combinations with various other modalities should be tried for better outcome. For safer and more efficacious combinations, more discussion and research is needed regarding the usage of HIFU, for example, a choice between overall irradiation or localized irradiation combined with another modality.