title: Navigation Guidance During Free Flap Mandibular Reconstruction: A Cadaveric Trial.
abstract: Segmental mandibulectomy for tumors that distort the buccal surface of the mandible present a reconstructive challenge.
  
  
  
  To determine whether mandible alignment after navigation-guided mandible reconstruction is better than alignment after non-template-assisted freehand reconstruction and as good as template-assisted reconstruction in a cadaveric trial.
  
  
  
  A cadaveric trial using 10 specimens was conducted at a tertiary academic center. Fiducials were created on the ramus to compare alignment with each intervention. Segmental mandibulectomy was performed on each cadaver. Each cadaver underwent navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction with plate contouring performed after mandibulectomy. The study was conducted from October 1, 2015, to January 1, 2016; data analysis was performed from February 1, 2016, to March 1, 2016.
  
  
  
  Segmental mandibulectomy, navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction.
  
  
  
  Ramus fiducial coordinates were recorded at baseline and after each intervention. Mandible dimensions were measured using cephalometric landmarks. Postintervention and baseline differences in ramus and mandible position were calculated.
  
  
  
  Ramus alignment was not significantly different between navigation-guided and template-assisted reconstruction, differing by 0.54 mm (98.3% CI, -0.38 to 1.47 mm). Non-template-assisted freehand reconstruction was associated with a 3.14-mm difference in alignment compared with template-assisted reconstruction (98.3% CI, 1.09 to 5.19 mm). Navigation-guided alignment resulted in a 3.69-mm improvement in alignment compared with non-template-assisted freehand reconstruction (98.3% CI, 1.79 to 5.58 mm). There was some improvement in the gonion-gonion and lingula mandibulae-lingula mandibulae (Lm-Lm) alignment for navigation-assisted compared with non-template-assisted freehand reconstruction by 1.97 mm (98.3% CI, -0.65 to 4.58 mm) and 1.39 mm (98.3% CI, -0.17 to 2.95 mm), respectively. There was marginal evidence of better Lm-Lm alignment for navigation-guided than template-assisted reconstruction (0.44 mm; 98.3% CI, -0.06 to 0.95 mm).
  
  
  
  Mandible alignment following navigation-guided reconstruction is similar to template-assisted reconstruction. Navigation-guided alignment is likely better than non-template-assisted freehand reconstruction, and navigation guidance offers a reliable technique for real-time adjustment when reconstructing complex surgical defects, such as tumors effacing the buccal cortex of the mandible.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle.
authors.forename: R Alex
authors.initials: RA
authors.lastname: Harbison
authors.affiliation: Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Shan
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Douglas
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle.
authors.forename: Scott
authors.initials: S
authors.lastname: Bevans
authors.affiliation: Department of Electrical Engineering, University of Washington, Seattle.
authors.forename: Yangming
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle.
authors.forename: Kris S
authors.initials: KS
authors.lastname: Moe
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle.
authors.forename: Neal
authors.initials: N
authors.lastname: Futran
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Houlton
mesh_terms: D002102:Cadaver; D058752:Free Tissue Flaps; D006801:Humans; D063175:Mandibular Reconstruction / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*