Oral and Maxillofacial Surgeon in Private Practice, Victoria, BC; Division of Anatomy, Department of Surgery, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
Division of Anatomy, Department of Surgery, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
J Plast Reconstr Aesthet Surg. 2023 Oct;85:508-514. doi: 10.1016/j.bjps.2023.07.003. Epub 2023 Jul 17.
Irreversible facial paralysis results in significant functional impairment. The motor nerve to the masseter is a reconstructive option, but despite its clinical importance, there are few parametric anatomic studies of the masseteric nerve. The purpose of this study was to investigate the extra- and intramuscular innervation of the masseter in 3D to determine the relationship of the nerve to the muscle heads and identify landmarks to aid identification.
The nerve was dissected throughout its entire course in eight formalin-embalmed cadaveric specimens (mean age 84.9 ± 12.2 years). The nerve was digitized at 1-2 mm intervals using a MicroScribe™ digitizer and modeled in 3D in Autodesk® Maya®.
Two or three extramuscular nerves were found to enter the deep head (DH) of the masseter: one main "primary" nerve (n = 8) and one (n = 4) or two (n = 4) smaller primary nerve(s). The main primary nerve supplied both the deep and superficial heads, whereas the smaller primary nerve(s) only supplied the DH. Surgical landmarks for masseter nerve localization were quantified.
Comprehensive mapping of the innervation of the masseter muscle throughout its volume revealed neural partitioning that could provide a basis for safety planning for muscle flaps and donor nerve identification and explain why masseter functional loss is not incurred by donor nerve sacrifice. Quantified landmarks correlate to previous studies and support the constant anatomy of this nerve. Our results provide a basis to optimize surgical approaches for donor nerve and muscle flap surgery.
不可逆性面瘫会导致显著的功能障碍。咀嚼肌运动神经是一种重建选择，但尽管其具有重要的临床意义，但对咀嚼肌神经的参数解剖学研究很少。本研究的目的是在 3D 中研究咀嚼肌的肌内和肌外神经支配，以确定神经与肌肉头的关系，并确定有助于识别的标志点。
在 8 个福尔马林固定的尸体标本中（平均年龄 84.9±12.2 岁），对神经进行了整个全程的解剖。使用 MicroScribe™数字化仪以 1-2mm 的间隔对神经进行数字化，并在 Autodesk®Maya®中进行 3D 建模。
发现有两个或三个肌外神经进入咀嚼肌深头（DH）：一个主要的“初级”神经（n=8）和一个（n=4）或两个（n=4）较小的初级神经。主要的初级神经供应深头和浅头，而较小的初级神经仅供应 DH。对咀嚼肌神经定位的手术标志点进行了量化。
对咀嚼肌整个体积的神经支配进行全面描绘，揭示了神经分区，这可能为肌肉瓣的安全规划和供体神经的识别提供基础，并解释了为什么供体神经牺牲不会导致咀嚼肌功能丧失。量化的标志点与先前的研究相关，并支持该神经的恒定解剖结构。我们的研究结果为优化供体神经和肌肉瓣手术的手术方法提供了依据。
