Points for Clarification

Abstract

I read this paper with interest and congratulate the operating surgeon on his low cranial nerve injury rates. I would be grateful for clarification regarding the following issues. Why were there 225 exclusions? Did the cranial nerve injuries occur early in the series or late and were they the reason for the stated change in approach? What is meant by ‘targeted follow-up’ and how long did the injuries take to resolve (i.e. was this a reflection of the effect of local anaesthetic infiltration or tension neuropraxia)? Why was the chi-squared test used for such small numbers of complications? First, the Fisher' exact test might have been more appropriate, and second there is the risk of confusing clinically significant differences with statistically significant differences. This is relevant in the consideration of haematoma (no statistically significant difference in proportions). Were the necks re-explored (a clinically significant outcome not commented upon) and, if so, was there a clear cause for the haematoma that would differ between the groups (e.g. a slipped ligature on the facial vein)? I agree with the conclusion that a much larger series would be needed to evaluate fully the difference in rates of nerve injury complications, but would suggest that a better conclusion would be that, in experienced hands, local anaesthetic carotid endarterectomy has a very low rate of permanent cranial nerve injury irrespective of approach.