Adverse drug reactions are appreciably harmful or unpleasant reactions resulting from an intervention related to the use of medical products, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product. Given medical case reports extracted from MEDLINE, the task is to classify whether the case report mentions the presence of any adverse drug reaction. Classify your answers into non-adverse drug event and adverse drug event.
Q: CONCLUSION: If a parotid duct injury is diagnosed at the time of tumor extirpation, then surgical repair of the duct should be attempted, but if surgical repair is not possible or if an injury remains unrecognized until well after tumor extirpation, then surgery is not necessary.
A: 
non-adverse drug event