**4. Pathophysiology**

Anterior cervical spine surgery impact both physiological and anatomical function of the swallowing, and these factors impact the neural, muscular & mucosal structures [19, 26]. However, in some cases dysphagia can occur in the absence of any noticed postoperative complication in anterior cervical spine surgery (ACSS).

We can summarize the etiology of dysphagia following anterior cervical spine surgery as the following:


#### **Table 1.**

*Causes of oropharyngeal dysphagia according to categories, with corresponding representative conditions [11].*


*Abbreviations: ET, endotracheal; rhBMP-2, recombinant human bone morphogenetic protein-2; RLN, recurrent laryngeal nerve; SLN, superior laryngeal nerve.*

#### **Table 2.**

*Causes of oropharyngeal dysphagia according to operative approach and operative technique.*
