[Intraoperative magnet in removal of intracerebral metallic foreign bodies].

Background: Advisability of magnets in neurotrauma is due to pattern of patients admitted to neurosurgical departments of military hospitals with wounds accompanied by intracranial fixation of foreign metallic ferromagnetic bodies.

Objective: To study dimensions, mass and magnetic properties of fragments extracted from gunshot wounds inflicted by modern weapons; to assess the feasibility of devices and instruments for removing foreign bodies.

Material and methods: We analyzed foreign bodies extracted after gunshot wounds. Shape, dimension, weight and magnetic properties were studied. We estimated 532 foreign bodies (497 surgeries) extracted at the Kirov Military Medical Academy and 83 foreign bodies (79 surgeries) extracted at the Burdenko Military Clinical Hospital. Distribution by anatomical regions was established for both groups. We intraoperatively used cylindrical neodymium magnets 3×20 and 5×20 mm to extract magnetic foreign bodies. These magnets were brought to the target using standard surgical tweezers or original devices.

Results: The median mass of removed fragments was 0.385 (Q₁-Q₃=0.12-1.435; min-max≤0.01-30.5) g at the Kirov Military Medical Academy and 0.4 (Q₁-Q₃≤0.001-1.6; min-max≤0.01-11.4) g at the Burdenko Military Clinical Hospital. Magnetic foreign bodies were found in 501 (94.2%) and 74 (94.8%) cases, respectively. In 8.8% of cases, foreign bodies were not removed due to difficult-to-reach location accompanied by higher risk of adverse outcomes after extraction.

Conclusion: Extracted foreign bodies after combat injuries have magnetic properties in 94% of cases. Intraoperative magnet allows for safe extraction of fragments in 91% of cases. Devices with adjustable magnetic field strength seem perspective. Further analysis of indications for removal of wounding projectiles in primary and, especially, repeated surgical treatment of craniocerebral wounds is needed.