when was the last time in 2104 patient 42905 had surgery?
select procedures_icd.charttime from procedures_icd where procedures_icd.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 42905 ) and strftime('%y',procedures_icd.charttime) = '2104' order by procedures_icd.charttime desc limit 1