Learning curve for the BHR, average 40 ops, but, could be longer. This surgeon says that one never stops 'learning'. good point. But, about 40 ops is considered the correct number of these BHR ops in order to have a level of competence. So, check out how many yr surgeon has actually done...!
(For myself, I'd opine, 40 BHR ops is insufficient to make for a really proficient and competent surgeon in this BHR discipline - me, I'd be looking for waaaaaaay more!!)