Safe Planes for Injection Rhinoplasty: A Histological Analysis of Midline Longitudinal Sections of the Asian Nose.

[BACKGROUND] Dorsal nasal augmentation is an essential part of injection rhinoplasty on the Asian nose. Aesthetic physicians require detailed knowledge of the nasal anatomy to accurately and safely inject filler.

[METHODS] One hundred and thirty-five histological cross sections were examined from 45 longitudinal strips of soft tissue harvested from the midline of the nose, beginning from the glabella to the nasal tip. Muscles and nasal cartilage were used as landmarks for vascular identification.

[RESULTS] At the nasal tip, a midline longitudinal columellar artery with a diameter of 0.21 ± 0.09 mm was noted in 14 cadavers (31.1 %). At the infratip, subcutaneous tissue contained cavernous tissue similar to that of the nasal mucosa. The feeding arteries of these dilated veins formed arteriovenous shunts, into which retrograde injection of filler may be possible. All of the nasal arteries present were identified as subcutaneous arteries. They coursed mainly in the superficial layer of the subcutaneous tissues, with smaller branches forming subdermal plexuses. A substantial arterial anastomosis occurred at the supratip region, in which the artery lay in the middle of the subcutaneous tissue at the level of the major alar cartilages. These arteries had a diameter ranging between 0.4 and 0.9 mm and were found in 29 of 45 specimens (64.4 %). This was at the level midway between the rhinion above the supratip and the infratip. This anastomotic artery also crossed the midline at the rhinion superficial to the origin of the procerus on the lower end of the nasal bone. Here the arterial diameter ranged between 0.1 and 0.3 mm, which was not large enough to cause arterial emboli. Fascicular cross sections of the nasalis muscle directly covered the entire upper lateral cartilage. The subdermal tissue contained few layers of fat cells along with the occasional small artery. The procerus arose from the nasal bone and was continuous with the nasalis in 16 cadavers (35.6 %). There was fatty areolar tissue between the procerus and the periosteal layer and no significant arteries present. The procerus ascended beyond the brow to insert into the frontalis muscle with very few cutaneous insertions. The supratrochlear vessels and accompanying nerve were occasionally found on the surface of the frontalis muscle.

[CONCLUSION] Most nasal arteries found in the midline are subcutaneous arteries. Filler should be injected deeply to avoid vascular injury leading to compromised perfusion at the dorsum or filler emboli at the nasal tip.

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