Really serious surgical blunders do not often occur. There should be careful checks and double-checks in place in all surgical units to ensure that operative notes clearly state what is to be done, precisely where, and to which carefully identified patient.
Mistakes such as operating on the wrong patient; on the wrong part of the body; or carrying out a completely incorrect procedure- are very likely to involve negligence somewhere and form the basis of a clinical negligence compensation claim for medical error.