PAPER 156: THE EFFECTS OF MRI ON SURGICAL STAPLES

Abstract

Purpose: Surgical staples are routine in closure of surgical incisions. Staples allow for expeditious closure and removal compared to suture materials. Concern exists, however, in obtaining an MRI scan when staples are present. The study analyzes common issues related to MRI scanning in the presence of surgical staples.

Method: Thirty pig feet had one-inch surgical incisions made and repaired with five standard stainless steel surgical staples. Two parameters were analyzed: temperature change on the skin surface and staples displacement. Once placed, each skin staple position was marked for later referencing. A surface temperature laser device (Fluke 62 Mini) recorded pre-scan skin surface temperature. A 35-minute MRI scan was performed using a 1.5 Tesla magnet with a standard knee coil for each of the pig feet in an MRI suite at ambient room temperature. Immediately afterwards, the skin surface temperature was recorded and distance measurements were made in relation to the pen markings. A paired T-test was utilized to analyze the pre and post-scan data.

Results: The mean temperature before the scans was 16.45 degrees Celsius with a standard deviation of 0.7 degrees. The median pre-scan temperature was 16.4 degrees. The minimum temperature was 14.6 degrees and maximum was 18.2 degrees. After scanning, the mean temperature was 16.02 degrees Celsius with a standard deviation of 0.63 degrees. The median post-scan temperature was 15.8 degrees. The minimum temperature was 15.0 and maximum temperature 17.6 degrees. The skin surface temperature showed a significant drop of 0.43 degrees Celsius (p=0.001). No change was recorded in staple position for any of the thirty pig feet pre-scan compared to post-scan.

Conclusion: Occasionally, patients require MRI scans after having surgery where staples have been used to repair the incision(s). Concern exists over heat generation or movement of the staples during the magnetic process. This study demonstrated no recordable increase in skin surface temperature or displacement of staple position after a standard extremity MRI scan. Based on the findings of this study, MRI scanning in the presence of surgical staples appears safe.