Is entire nerve root decompression necessary for hemifacial spasm?

The root exit zone (REZ) of the seventh cranial nerve has been the target of microvascular decompression surgery (MVD) while searching the neurovascular conflict for treatment of hemifacial spasm for long time. Recently, increasing cases regarding the offending vessel beyond the REZ have been reported. To verify whether a thorough dissection of the nerve may give rise to a better postoperative result without enhancing complications, we conducted a parallel investigation.

112 Connective entire-nerve-exposed MVDs were performed and compared to 186 REZ-exposed MVDs performed by the same group of surgeons in 2009. The surgical findings, postoperative outcomes and complications as well as microscopic operating time were examined.

Immediately after the surgery, the outcomes were excellent in 98.2%, good in 1.8% and poor in 0% in the entire-nerve-exposed group, compared to excellent in 92.5%, good in 1.6% and poor in 5.9% in the REZ-exposed group. The difference of outcomes between the two groups were statistically significant (χ(2)=4.6845, P=0.0304), but not the complications and microscopic operating time. Nine of the 11 poor-outcome patients from the REZ-exposed group were then reoperated on within a few days, and their symptoms disappeared in eight patients. The main reason for the failed surgeries was that the offending vessels beyond REZ were missed.

These findings suggested that the entire-root-decompression technique is recommended while performing MVDs in patients with hemifacial spasm.