Pearls and Pitfalls in Head and Neck Surgery Thyroid and Parathyroid Glands

Introduction The terms ‘inferior’ and ‘recurrent’ laryngeal nerve have been used interchangeably to describe a branch of the thoracic vagus that loops around the subclavian artery (on the right) or aortic arch (on the left), and then ascends to terminally arborize [1]. The ILN carries sensory, motor and parasympathetic fibers, and divides into an internal branch (sensory to the vocal cords and subglottis) and external branch (motor to the intrinsic muscles of the larynx except cricothyroid). In as many as 70% of cases, this branching is extralaryngeal, predisposing a branch of the nerve to injury. In the vast majority of these cases, this bifurcation occurs more than 1.0 cm from the cricoid cartilage [2, 3]. ILN dysfunction is among the most common, feared and litigious complications of cervical explorations, and is associated with temporary or permanent vocal cord dysfunction. When bilateral injury occurs, the morbidity is even more dramatic, often requiring tracheostomy.