how many oth extraoc mus-tend op procedures were performed this year?
select count(*) from procedures_icd where procedures_icd.icd9_code = ( select d_icd_procedures.icd9_code from d_icd_procedures where d_icd_procedures.short_title = 'oth extraoc mus-tend op' ) and datetime(procedures_icd.charttime,'start of year') = datetime(current_time,'start of year','-0 year')