Anat Cell Biol.  2024 Dec;57(4):498-502. 10.5115/acb.23.255.

Ultrasonographic study and anatomical guidelines for botulinum neurotoxin injection into the parotid gland

• Yi KH
• Kim SB
• Hu H
• Kim HJ

• KMID: 2562496
• DOI: http://doi.org/10.5115/acb.23.255

Abstract

Benign enlargement of the parotid gland hypertrophy results in a bulky lateral facial contour and esthetic appearance. This study aimed to determine the depth from the skin surface to the parotid fascia, which encompasses the parotid gland. The anatomical properties of the parotid glands were evaluated in 40 patients using ultrasonography. An upto-date understanding of the localization of botulinum neurotoxin (BoNT) injection based on anatomy could lead to better localization of the injection into the parotid gland through morphological measurements using data previously published from cadaveric studies. Measurement using the otobasion inferius as a landmark revealed parotideomasseteric fascia thickness averaging 4–6 mm from the skin surface, with the parotid gland extending approximately 15 mm anteriorly. Analysis showed a 3–7 mm thickness range, indicating an optimal injection depth for safety and efficacy in BoNT procedures. Utilizing the otobasion inferius as an anatomical landmark offers a practical approach for measuring parotideomasseteric fascia thickness, addressing cadaveric study limitations. These guidelines aim to maximize the effects of BoNT therapy, which can be useful in clinical settings, by minimizing its deleterious effects.

Keyword

Botulinum neurotoxin; Parotid gland; Injections; Ultrasonography; Hypertrophy

Figure

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  Fig. 1 The probe was positioned vertically along the gonion and the zygomatic process of the temporal bone (A), and horizontally at the midpoint where it crosses the otobasion inferius (B).

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  Fig. 2 When observed vertically, the distance from the skin to the parotid gland and the thickness of the gland at at otobasion inferius point were 4.52±0.81 mm and 4.96±2.39 mm, respectively. The asterisk denotes the parotid gland. Superf., superficial; Sup., superior; Gog’, gonion.

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  Fig. 3 When measured horizontally, the distance from the skin to the parotid gland and the thickness of the parotid gland at its thickest part were 4.84±0.81 mm and 5.12±1.89 mm, respectively. Additionally, the parotid gland extended 15.43±2.83 mm anterior to the otobasion inferius. The asterisk denotes the parotid gland. Superf., superficial; Med., medial; Gog’, gonion.

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  Fig. 4 Numerous anatomical structures, including branches of the facial nerve, external carotid artery, superficial temporal artery, and the parotid duct, traverse the parotid gland from its deepest part, passing through its border to reach more superficial regions. br., branch.

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  Fig. 5 The recommended points and depth for botulinum toxin injection into the parotid gland. Injection at a depth of 6–7 mm ensures safety and effectiveness, given the parotideomasseteric fascia is 4–6 mm from the skin at the otobasion inferius, and the parotid gland thickness is 3–7 mm.

Reference

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