Charing Cross Hospital, Imperial College Healthcare NHS Trust, United Kingdom of Great Britain and Northern Ireland.
Walsall Healthcare NHS trust, UK.
Am J Otolaryngol. 2022 Jan-Feb;43(1):103271. doi: 10.1016/j.amjoto.2021.103271. Epub 2021 Oct 20.
Iatrogenic facial nerve palsy is distressing to the patient and clinician. The deformity is aesthetically displeasing, and can be functionality problematic for oral competence, dental lip trauma and speech. Furthermore such injuries have litigation implications. Marginal mandibular nerve (MMN) palsy causes an obvious asymmetrical smile. MMN is at particular risk during procedures such as rhytidoplasties, mandibular fracture, tumour resection and neck dissections. Cited causes for the high incidence are large anatomical variations, unreliable landmarks, an exposed neural course and tumour grade or nodal involvement dictating requisite nerve sacrifice. An alternative cause for post-operative asymmetry is damage to the cervical branch of the facial nerve or platysmal dysfunction due to its division. The later tends to have a transient course and recovers. Distinction between MMN palsy and palsy of the cervical branch of the facial nerve or platysma division should therefore be made. In 1979 Ellenbogen differentiated between MMN palsy and "Pseudo-paralysis of the mandibular branch of the facial nerve". Despite this, there is paucity in the literature & confusion amongst clinicians in distinguishing between these palsies, and there is little regarding these post-operative sequelae and neck dissections.
This article reflects on the surgical anatomy of the MMN and cervical nerve in relation to danger zones during lymphadenectomy. The authors review the anatomy of the smile. Finally, case studies are utilised to evaluate the differences between MMN palsy and its pseudo-palsy to allow clinical differentiation.
Here we present a simple method for clinical differentiation between these two prognostically different injuries, allowing appropriate reassurance, ongoing therapy & management.
医源性面神经麻痹给患者和临床医生带来困扰。这种畸形不仅影响美观，还会导致口腔功能障碍、唇部外伤和言语问题。此外，此类损伤还涉及法律诉讼。下颌缘支神经（MMN）麻痹会导致明显的不对称微笑。在除皱术、下颌骨骨折、肿瘤切除术和颈部淋巴结清扫术等手术中，MMN 特别容易受损。高发病率的原因包括解剖结构变异大、可靠的标志不明显、神经暴露和肿瘤分级或淋巴结受累导致必需的神经牺牲。术后不对称的另一个原因可能是面神经颈支或颈阔肌功能障碍引起的损伤，后者往往是暂时的，并会恢复。因此，应区分 MMN 麻痹与面神经颈支或颈阔肌分支麻痹。1979 年，Ellenbogen 将 MMN 麻痹与“面神经下颌支假性麻痹”区分开来。尽管如此，文献中对此类麻痹的区分仍很少见，临床医生对此也存在混淆，关于这些术后后遗症和颈部淋巴结清扫术的信息也很少。
本文回顾了 MMN 和颈部神经的手术解剖与淋巴结清扫术中危险区域的关系。作者回顾了微笑的解剖结构。最后，通过病例研究来评估 MMN 麻痹及其假性麻痹之间的差异，以便进行临床区分。
我们在此提出了一种简单的方法，用于临床区分这两种预后不同的损伤，以便进行适当的安慰、持续治疗和管理。
