Inferior alveolar nerve injury after sagittal split osteotomy

Bilateral sagittal split osteotomy (BSSO) is a commonly used for treating mandibular deformity. As it is performed in close proximity to the inferior alveolar nerve (IAN) there is frequently nerve damage. IAN damage at operation has been reported to vary from 1.3-18% with postoperative disturbances ranging from 9-85%.

The aim of this review was to review the reported incidence of inferior alveolar nerve injury after orthognathic surgery and to assess the methods used to evaluate IAN sensory disturbances in reports published between 1990 and 2013.

Methods

Searches were conducted in the Medline, Web of Knowledge, OneFile, and online plat- forms of various publishers. Two reviewers carried out study selection independently. Randomised, non-randomised clinical trial, cohort studies, case–control studies, case reports in English were considered.

Results

61 studies were included.
16 studies (26.0%) did not indicate the incidence of IAN injury
Pre-operative status of the IAN was also not assessed in 22 reports (36.1%)
Only 21 studies (34.4%) provided details of the IAN assessor
IAN neurosensory disturbance was assessed:-
- Subjectively in 47 papers (77.0%)
- Objectively in only 14 of the papers (23.0%); seven of the studies used only objective method and 7 both subjective and objective methods
Overall incidence of IAN disturbance varied from 1.6% to 90%

Conclusions

The authors concluded

The observed wide variation in the reported incidence of inferior alveolar nerve injury is due to a lack of standardized assessment procedures and reporting. Thus, an international consensus meeting on this subject is needed in order to establish a standard-of-care method.

Commentary

The details of the search for this review were a little vague and restricted to the English language so it is possible that some relevant studies may have been missed. As IAN damage is a recognised complication of the BSSO it is strange that almost 26% of the included studies did not provide figures for incidence. The authors also note variation in the time-point at which damage is assessed and the variations between objective and subjective approaches to assessment. The authors highlight that there is no purely objected method of clinically assessing iatrogenic injury to the terminal branches of the trigeminal nerve but the BSSO was first described in 1957 so the call for standardised assessment and reporting procedures is long overdue.