title: Prevertebral corridor: posterior pathway for reconstruction of the ventral skull base.
abstract: OBJECTIVE
  Regional vascularized flaps, such as the pericranial and temporoparietal fascia flaps, are currently used for reconstruction of skull base defects after endoscopic endonasal surgery whenever local vascularized flaps, such as the nasoseptal flap, are not available. Two different transposition pathways, infratemporal transpterygoid and subfrontal, have been proposed for regional flaps. The objective of this study was to describe and assess the feasibility of the transposition of a vascularized pedicled flap from the occipital galeopericranium via the prevertebral space corridor into the nasopharynx.
  
  
  METHODS
  Ten heads were injected with colored silicone. An endoscopic endonasal anterior craniofacial resection and panclival approach were performed in each specimen. The occipital flap was harvested using a previously described technique. The prevertebral corridor, extending from the neck to the nasopharynx, was dissected superficial to the paraspinal muscles. Computed tomography-based image guidance was used to assess the relationship between the corridor and adjacent neurovascular structures. Length of the corridor and pedicle and area of the donor flap were measured.
  
  
  RESULTS
  The flap was harvested and successfully transposed into the nasopharynx using the proposed corridor in all studied specimens (10 heads, 20 sides). All flaps provided complete coverage of the skull base defects. The average length of the pedicle was 70.5 (SD, 6.5) mm, and the average length and width of the flap were 99.9 (SD, 14.6) mm and 59.3 (SD, 10.9) mm, respectively. The average length of the prevertebral corridor was 49.7 (SD, 4.8) mm.
  
  
  CONCLUSIONS
  The occipital flap has favorable anatomic characteristics for use in skull base reconstruction. Transposition of the flap via the prevertebral corridor is a suitable option for vascularized reconstruction of expanded endonasal skull base defects when other local or regional flaps are not available. Additional clinical studies are necessary to define its role in endoscopic endonasal surgery.
authors.affiliation: Department of Otorhinolaryngology & Head and Neck Surgery, Gulhane Military Medical School, Ankara, Turkey. adurmaz@gata.edu.tr
authors.forename: Abdullah
authors.initials: A
authors.lastname: Durmaz
authors.forename: Juan
authors.initials: J
authors.lastname: Fernandez-Miranda
authors.forename: Carl H
authors.initials: CH
authors.lastname: Snyderman
authors.forename: Carlos
authors.initials: C
authors.lastname: Rivera-Serrano
authors.forename: Fuat
authors.initials: F
authors.lastname: Tosun
mesh_terms: D002102:Cadaver; D004724:Endoscopy / Q000379:methods; D005240:Feasibility Studies; D006801:Humans; D009296:Nasal Cavity / Q000601:surgery; D015641:Radiography, Interventional; D019651:Plastic Surgery Procedures / Q000379:methods*; D019291:Skull Base / Q000601:surgery*; D013524:Surgical Flaps / Q000098:blood supply*; D014057:Tomography, X-Ray Computed