INTRODUCTION
Salivary duct stenosis is the second most common (15 to 50%) cause of chronic obstructive sialadenitis following sialolithiasis.1 It is associated with chronic inflammatory changes induced by allergy, stones, post-retrieval of stones, trauma, autoimmune, and radioiodine therapy.2,3 These conditions often lead to reduced salivary flow, ascending duct infection, and formation of mucous or fibrous plaques and stricture in salivary gland ducts.4 Patients with salivary duct stenosis typically present with recurrent swelling, pain, or discomfort of the affected glands that is frequently aggravated during or between meals.5
Salivary duct stenosis commonly involves the parotid glands (67 to 75%).6 Sialendoscopy allows direct examination of the tissue characteristics of stenotic lesions in the parotid ducts. Kochet al . described three types of stenosis as follows: inflammatory (type 1), web-like or circular (type 2), and fibrotic or diffuse (type 3) luminal narrowing.7,8 Type 1 appears to be a precursor of type 3 stenosis, showing a progressive diffuse narrowing in the segmental or entire duct.7 In contrast, type 2 stenosis typically tends to form a focal stricture accompanied by a megaduct with a thin wall due to dilation secondary to mechanical obstruction. Patients with type 2 stenosis often feel their cheek swelling while eating, owing to the pooling of saliva in the reservoir-like megaduct. The stenotic duct can also be classified into grade 1 (swollen but minimal narrowing), grade 2 (luminal narrowing < 50%), and grade 3 (luminal narrowing ≥ 50%) according to the luminal narrowing severity based on sialendoscopic visualization.9 The stenotic lesions of type 2 stenosis accompanied by a megaduct commonly show higher grades of narrowing, while types 1 and 3 exhibit varying grades of stenosis.7,10
Dilation of the stenotic duct is the primary treatment goal for relieving patients from obstructive symptoms, although conservative care with sialagogue and gland massage sometimes benefit patients with chronic obstructive sialadenitis caused by autoimmune or radioiodine therapy.11,12 The sialendoscopic approach is safe and effective for treating patients with salivary duct stenosis, with satisfactory clinical outcomes for relieving symptoms.4,13,14 However, resolving the stenotic ducts remains a surgical challenge when sialendoscopy fails to dilate the stenotic lesions mechanically. The so-called transoral (pull-through) sialodochoplasty, a surgical technique to remove the stenotic portion of an involved duct and connect the remaining duct to the buccal mucosa, has been described in several reports.15-17 However, the efficacy of transoral sialodochoplasty has not yet been investigated. This study aimed to analyze the surgical outcomes of sialendoscopy combined with transoral sialodochoplasty through the evaluation of changes in obstructive symptoms, characteristics in the stenotic lesion with a megaduct, and excretory salivary flow of patients with type 2 stenosis in parotid glands.