title: Optical nerve detection by diffuse reflectance spectroscopy for feedback controlled oral and maxillofacial laser surgery.
abstract: BACKGROUND
  Laser surgery lacks haptic feedback, which is accompanied by the risk of iatrogenic nerve damage. It was the aim of this study to investigate diffuse reflectance spectroscopy for tissue differentiation as the base of a feedback control system to enhance nerve preservation in oral and maxillofacial laser surgery.
  
  
  METHODS
  Diffuse reflectance spectra of nerve tissue, salivary gland and bone (8640 spectra) of the mid-facial region of ex vivo domestic pigs were acquired in the wavelength range of 350-650 nm. Tissue differentiation was performed using principal component (PC) analysis followed by linear discriminant analysis (LDA). Specificity and sensitivity were calculated using receiver operating characteristic (ROC) analysis and the area under curve (AUC).
  
  
  RESULTS
  Five PCs were found to be adequate for tissue differentiation with diffuse reflectance spectra using LDA. Nerve tissue could be differed from bone as well as from salivary gland with AUC results of greater than 88%, sensitivity of greater than 83% and specificity in excess of 78%.
  
  
  CONCLUSIONS
  Diffuse reflectance spectroscopy is an adequate technique for nerve identification in the vicinity of bone and salivary gland. The results set the basis for a feedback system to prevent iatrogenic nerve damage when performing oral and maxillofacial laser surgery.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Erlangen University Hospital, Erlangen, Germany. Florian.Stelzle@uk-erlangen.de
authors.forename: Florian
authors.initials: F
authors.lastname: Stelzle
authors.forename: Azhar
authors.initials: A
authors.lastname: Zam
authors.forename: Werner
authors.initials: W
authors.lastname: Adler
authors.forename: Katja
authors.initials: K
authors.lastname: Tangermann-Gerk
authors.forename: Alexandre
authors.initials: A
authors.lastname: Douplik
authors.forename: Emeka
authors.initials: E
authors.lastname: Nkenke
authors.forename: Michael
authors.initials: M
authors.lastname: Schmidt
mesh_terms: D000818:Animals; D004058:Diffusion; D053685:Laser Therapy / Q000379:methods*; D008954:Models, Biological; D009055:Mouth / Q000601:surgery*; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D019647:Oral Surgical Procedures / Q000379:methods*; D011379:Prognosis; D011859:Radiography; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods; D013552:Swine; D016896:Treatment Outcome