Anatomical Variation of Zygomatic Nerve Branches around Zygomaticus Major Muscle in Facelift.

Sir:

To improve midfacial soft-tissue sagging, it is sometimes necessary to release the zygomatic and upper masseteric retaining ligaments in the sub-superficial musculoaponeurotic system (SMAS) plane. Release of these ligaments needs to be done carefully to avoid any injuries to the branches of the facial nerve. Some of the zygomatic branches run toward the zygomaticus major muscle and are located deep to the fascia and pass deep under a third of the zygomaticus major muscle.[1,2] However, anatomical variations of the zygomatic branches were found. This is a case of the anatomic variations of the zygomatic branches seen unilaterally in a single patient undergoing a facelift.

MATERIALS AND METHODS

A healthy 66-year-old female patient underwent a facelift procedure (Fig. 1).

Fig. 1.

The zygomatic nerve branch (black arrow) penetrated from the deep fascia about 1 cm lateral to the origin of the zygomaticus major muscle (blue arrow); one ramus (red arrow) innervated the orbicularis oculi muscle. Other ramus (green arrow) passed superficially above the upper third of the muscle.

RESULTS

After the zygomatic and upper masseteric retaining ligaments were released in the sub-SMAS plane, an anatomical variation of the zygomatic branches was identified lateral to the origin of the zygomatic major muscle only on the left side. The branches penetrated from the deep fascia about 1 cm lateral to the origin of the zygomaticus major muscle; one ramus innervated orbicularis oculi muscle and the other ramus passed superficially above the upper third of the muscle. On the right side, this was not seen. The main zygomatic retaining ligaments are located immediately lateral to the origin of the zygomaticus major muscle. The zygomatic branches are usually located deep to the deep fascia in the lateral area of the muscle and pass deep under a third of the muscle. Therefore, the branches are protected while the retaining ligaments are dissected in the sub-SMAS plane. However, in this patient, the risk of the zygomatic branch injury is higher, so blunt dissection, adequate vertical traction of the SMAS flap, and the use of tumescent solution are needed to visually differentiate between the retaining ligaments and the nerve branches to avoid any injury.[3]

CONCLUSIONS

We should be aware of this unique case where the variation was only seen unilaterally. Particular care must be taken when dissection is performed to release the retaining ligaments. We hope this case can contribute to avoiding nerve injuries in facelift procedures.