title: Subjective sensory symptoms associated with axonal and demyelinating nerve injuries after mandibular sagittal split osteotomy.
abstract: OBJECTIVE
  The effect of the type of nerve injury on subjective sensory disturbances and recovery has not been addressed in orthognathic surgery. Using neurophysiologic monitoring during 19 bilateral sagittal split osteotomy operations, we were able to classify intraoperative inferior alveolar nerve injuries as either axonal or demyelinating. This study aimed to analyze the quality and extent of the subjective sensations experienced by the patients after these 2 injury types at different time points up to 12 months.
  
  
  METHODS
  Of the 36 injured nerves, 21 showed signs of demyelinating injury and 15 showed signs of axonal damage. The quality of subjective sensory symptoms was asked about at 2 weeks and 1, 3, 6, and 12 months postoperatively and classified into 4 categories: normal, negative, positive (including pain), and mixed sensations. In addition, the extent of the sensory alteration was determined by measuring the affected skin regions from symptom charts.
  
  
  RESULTS
  The quantity, quality, and evolution of experienced subjective sensations differed between the injury types during follow-up: Subjective sensations normalized more rapidly after demyelinating-type injuries than after axonal-type injuries. Persistence of mixed sensation patterns at 3 months and appearance instead of disappearance of positive sensory phenomena after 3 months indicated axonal damage. Painful sensations at 1 month or later after surgery indicated axonal damage and predicted poor recovery and more long-term sequelae.
  
  
  CONCLUSIONS
  Postoperative pain at 1 month and type of nerve injury are important prognostic factors for the persistence of subjective symptoms and development of neuropathic pain.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Turku, Turku, Finland. tuitee@utu.fi
authors.forename: Tuija
authors.initials: T
authors.lastname: Teerijoki-Oksa
authors.forename: Satu K
authors.initials: SK
authors.lastname: Jääskeläinen
authors.forename: Tero
authors.initials: T
authors.lastname: Soukka
authors.forename: Arja
authors.initials: A
authors.lastname: Virtanen
authors.forename: Heli
authors.initials: H
authors.lastname: Forssell
mesh_terms: D000293:Adolescent; D000328:Adult; D001369:Axons; D003711:Demyelinating Diseases / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery*; D008340:Mandibular Nerve / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009431:Neural Conduction; D009437:Neuralgia / Q000209:etiology; D010027:Osteotomy / Q000009:adverse effects*; D011379:Prognosis; D020127:Recovery of Function; D063173:Retrognathia / Q000601:surgery; D012678:Sensation Disorders / Q000209:etiology*; D061221:Trigeminal Nerve Injuries; D055815:Young Adult