title: Evaluation of upper lip hypoesthesia with a trigeminal somatosensory-evoked potential following Le Fort I osteotomy in combination with mandibular osteotomy.
abstract: OBJECTIVE
  The purpose of this study was to objectively evaluate hypoesthesia of the upper lip following Le Fort I osteotomy in combination with mandibular osteotomy with trigeminal somatosensory evoked potential (TSEP).
  
  
  METHODS
  The subjects consisted of 25 patients with mandibular prognathism with maxillary retrognathism mandibular prognathism with or without asymmetry, who underwent Le Fort I osteotomy in combination with sagittal split ramus osteotomy (SSRO) or intraoral vertical ramus osteotomy (IVRO). Trigeminal nerve hypoesthesia at the region of the upper lip was assessed bilaterally by the TSEP method. The electrodes were placed exactly above the highest point of the vermilion border and on the mucosa of the upper lip. An electroencephalograph recording system (Neuropack Sigma; Nihon Koden Corp., Tokyo, Japan) was used to analyze the potentials. Each patient was evaluated preoperatively and then postoperatively at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year.
  
  
  RESULTS
  The average measurable period and standard deviation of TSEP of the upper lip was 7.8 +/- 10.7 weeks following Le Fort I osteotomy, TSEP of the lower lip was 4.6 +/- 9.2 weeks in the patients who underwent SSRO with Le Fort I osteotomy, and 1.2 +/- 0.4 weeks in the patients who underwent IVRO with Le Fort I osteotomy.
  
  
  CONCLUSIONS
  This study objectively proved that hypoesthesia could appear in the upper lips following Le Fort I osteotomy with TSEP. The measurable period for the upper lip following Le Fort I osteotomy tended to be longer than that for the lower lip in the patients who underwent SSRO and IVRO with Le Fort I osteotomy.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan. kueki@med.kanazawa-u.ac.jp
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ueki
authors.forename: Kiyomasa
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Kohei
authors.initials: K
authors.lastname: Marukawa
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shimada
authors.forename: Kan
authors.initials: K
authors.lastname: Yoshida
authors.forename: Yukari
authors.initials: Y
authors.lastname: Hashiba
authors.forename: Chika
authors.initials: C
authors.lastname: Shimizu
authors.forename: Etsuhide
authors.initials: E
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D020209:Cranial Nerve Injuries / Q000175:diagnosis*; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D006987:Hypesthesia / Q000175:diagnosis* / Q000209:etiology; D019248:Jaw Fixation Techniques / Q000295:instrumentation; D008046:Lip / Q000294:innervation*; D008297:Male; D008334:Mandible / Q000601:surgery; D019340:Osteotomy, Le Fort / Q000009:adverse effects*; D011378:Prognathism / Q000601:surgery; D063173:Retrognathia / Q000601:surgery; D061221:Trigeminal Nerve Injuries