title: Microanatomic study of the vascular and duct system of the submandibular gland.
abstract: OBJECTIVE
  Autologous microvascular submandibular gland (SMG) transfer is an effective treatment for severe keratoconjunctivitis sicca (KCS). However, epiphora (excessive tear secretion) may occur after the successful transfer of whole submandibular gland because tear secretion level is closely related to the size of the transferred gland. The aim of this study was to investigate the microanatomy of SMG to explore the possibility of partial SMG transfer to prevent postoperative epiphora.
  
  
  METHODS
  Sixty intact and histologically normal human SMGs from patients with benign tumor of the mandible who underwent vascularized mandibular reconstruction and removal of the SMG for anastomosis of the blood vessels were included in the study. SMGs were perfused with methacrylate to form resin casts of blood vessels and ducts. The length and diameter of the blood vessels and ducts in the casts were measured using a sliding caliper. The numbers of lobules, distribution of arteries, veins, and ducts, as well as the relationship among them, were analyzed.
  
  
  RESULTS
  The resin cast of the gland showed a treelike structure, with the vessels gradually dividing into multiple branches. The arteries, veins, and ducts run in parallel and were roughly divided into 3 levels: from the stem extending into the main branches (level I), into the narrower secondary branches (level II), and then the secondary branches subsequently divided into terminal branches (level III). The structures of the blood vessels and ducts were similar at each level in the lobules. In the vein casts, communicating vessels were found between the anterior facial vein and the concomitant vein of the facial artery.
  
  
  CONCLUSIONS
  The characteristic treelike structure of the SMG vascular and ductal system may provide useful information for partial gland transfers.
authors.affiliation: Department of Stomatology, Affiliated Beijing, Tong Ren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Xu
authors.forename: Chi
authors.initials: C
authors.lastname: Mao
authors.forename: Jing-Ming
authors.initials: JM
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Peng
authors.forename: Zheng-Hong
authors.initials: ZH
authors.lastname: Zhu
authors.forename: Guang-Yan
authors.initials: GY
authors.lastname: Yu
mesh_terms: D000328:Adult; D001158:Arteries / Q000033:anatomy & histology; D001160:Arterioles / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D007638:Keratoconjunctivitis Sicca / Q000601:surgery; D007766:Lacrimal Apparatus Diseases / Q000517:prevention & control; D008297:Male; D055806:Microvessels / Q000033:anatomy & histology*; D011183:Postoperative Complications / Q000517:prevention & control; D018987:Salivary Ducts / Q000033:anatomy & histology*; D013363:Submandibular Gland / Q000033:anatomy & histology* / Q000098:blood supply / Q000637:transplantation; D014680:Veins / Q000033:anatomy & histology; D014699:Venules / Q000033:anatomy & histology