Non-invasive therapy for altered facial sensation following orthognathic surgery: an exploratory randomized clinical trial of intranasal vitamin B12 spray.

Aim: The aim of the study was to obtain pilot data on the putative effects of intranasal spray Vitamin B12 in lessening the impairment from orthognathic surgery on large and small diameter nerve fiber functions.

Methods: Thirty-five subjects scheduled for a mandibular osteotomy were enrolled in an open-label two-group parallel stratified-block randomized clinical trial: Intranasal Vitamin B12 Spray (B12), with weekly doses self-administered two weeks before until 6 months after surgery, or no intranasal spray. All subjects received sensory retraining exercises. Large fiber tactile (contact detection) and small fiber thermal (warm, cool, heat discomfort, and cold discomfort) thresholds were obtained before and at 1, 3, and 6 months after surgery. For each, the mean maximum impairment was estimated for group and visit, controlling for age and type of surgery.

Results: The demographics and pre-surgery threshold values of the two groups did not differ (P>0.16). At and 6 months after surgery, serum B12 levels were substantially higher in the B12 group (P<0.01). At one month post, average impairment for every threshold measure was less for the B12 group. From 1 to 3 months, the differences between the two groups decreased for the tactile measures but stayed the same (cool and warm perception) or increased (cold and heat discomfort perception) for the thermal measures. At 6 months, the B12 group remained less impaired for the thermal measures.

Conclusion: This pilot RCT indicates that the effects of intranasal Vitamin B12 spray, initiated prior to surgery, on sensory function are sufficiently promising to justify progression to a Phase III RCT.