Neurologic damage after mandibular fractures

Introduction: Mandibular fractures conclude the vast majority of facial fractures, ranging between 70- 77%. One of the severe complications in mandibular fractures is neurologic damages, which appear in 20-40%, mostly in displaced fractures. The aim of the study was to summarize neurological damage prevalence post mandibular fractures, and trace the nerve recovery. Materials and Methods: The research included all adult patients, treated for mandibular fractures in Hadassah Medical Center during the years 2001-2008 - total of 424 mandibular fracture sites in 304 patients. The retrospective data was collected from patients' files, and descriptive statistics was performed including fracture site and type, and treatment modality. The recent 25 patients with reported neurological parasthesia, were scheduled for clinical examination, performing 2 point discrimination test (2PD) and electrodiagnostic conduction test (sNCT/CPT) in different nerve bundle types. Results: post injury nerve damage was diagnosed in 21.1% of patients. There was a strong correlation between fracture severity and treatment modality– Simple fractures were mostly treated with IMF (55.3%), while compound, greenstick and comminuted fractures were treated with ORIF (52.7%, 77.8% and 83.9% respectively). There was statistic significance between fracture severity and post treatment nerve damage (p<0.001). Non-displaced fractures were correlated to nerve damage in only 15.2%, while fractures displaced more than 5mm presented nerve damage in 70.8% of the cases. Patients' 2PD and electro-diagnostic test revealed significant difference between the injured side and the healthy side (p<0.0003, p<0.0002 respectively). Full nerve recovery was diagnosed in 36% of the patients presented with post operative neural deficiency. Conclusions: The current study presented the prognostic importance of the fracture type and displacement amount on neurologic deficit. There is higher nerve excitation threshold on the injured side, demonstrating objective neurosensory damage. In the current data cohort, type C nerve fiber was the most damaged and the less regenerated one.