Medicine Corp and Healthy Green Living Guide – Medcorpgreen.com

Archive for the ‘Radiology’ Category

Facial nerve injuries are rarer than trigeminal nerve complications, which is partly attributed to the fact that the trigeminal is a somatosensory nerve. In standard fractionation head and neck cases, the facial nerve routinely receives over 70 Gy without complication. Multiple fraction regimens treating cases of vestibular schwannoma have resulted in facial nerve preservation rates of 94% to 100%.With modern stereotactic radiosurgery planning techniques employing MRI and a margin dose less than or equal to 13 Gy, the risk of permanent facial weakness has been reduced to less than 1% in most series.

This is a clear improvement over older series showing complication rates of approximately 30% for patients who received marginal doses as high as 20 Gy using CT planning. As with the trigeminal nerve, Beegle and colleagues found the facial nerve to have an approximate six-fold increase in complication risk for every 2.5 Gy above 12.5 Gy prescribed to the tumor margin. Only marginal dose correlated with facial weakness in a review of 190 subjects described by Flickinger and colleagues involving modern radiation techniques, with no subject experiencing facial weakness with doses less than 15 Gy.