Complications associated with needle localization biopsy of the breast. A review of 144 consecutive needle localization biopsies of the breast (NLBB) was performed to assess complications associated with this procedure. Thirty-four complications occurred in 27 patients. There were 11 wound infections associated with NLBB. During this time period, there were 1,583 clean general surgical operations performed, other than biopsy of the breast, yielding an over-all wound infection rate of 1.2 per cent (p less than 0.001). A trend was noted, suggesting that use of drains may have contributed to wound infection versus no drainage (25 versus 5 per cent, respectively). Electrocautery burns requiring local wound care occurred during seven biopsies and four of these patients subsequently had a wound infection develop. Four lesions required more than one excision to remove the abnormal mammary tissue, and in four, there was a failure to remove the lesion at the first operation. Fifty-three localization procedures were performed using methylene blue. In this group, only one patient required more than one biopsy to remove the abnormal mammary tissue, and there were no failures with this technique. Also, a smaller mean volume of tissue was removed in this group versus the standard NLBB (30.2 +/- 3.0 versus 53.3 +/- 4.6 cubic millimeters, respectively) (p less than 0.01). Four cardiovascular complications occurred, requiring overnight admission. All of these patients were more than 65 years old and had the procedure performed while under general anesthesia. Patient age, type of anesthesia, resident versus attending surgeon and length of procedure had no independent effect on local complication rate. 