Spontaneous migration of retained intracranial missiles: experience with 16 cases

Spontaneous migration of retained intracranial missiles is uncommon but a potentially serious phenomenon. Our objective is to increase awareness of the risk of spontaneous migration of retained intracranial missiles by reporting our case series of 16 patients. We performed a retrospective single-center study on patients treated for intracranial missile injuries between 2000 and 2010 in Palestine with a particular focus on the migration of retained intracranial missiles. Detailed analyses were made of patients' age, sex, type of injurious agents (metallic bullets/rubber bullets/metallic shrapnel from bomb explosion), initial missile position, site to where the missile migrated, radiological and neurological manifestations, complications, treatment modalities (surgery vs. conservative) and functional outcome by Glasgow outcome scale-extended (GOSE) classification at last follow-up. In a cohort of 190 patients with retained intracranial missiles, we identified 16 (8.4%) patients with spontaneous migration. Patients' age ranged from 10 to 30 years (mean: 18.9 ± 6.4 years). There were only 2 female patients. The missiles that migrated intracranially were metallic bullets (n = 10), rubber bullets (n = 3), and metallic shrapnel from a bomb explosion (n = 3). Among the 16 patients, 10 patients experienced symptoms due to missile migration and were treated surgically, while six patients did not develop new symptoms after missile migration and were managed conservatively. In our case series, 16/190 (8.4%) patients with retained intracranial missiles developed spontaneous migration. Neurosurgeons performing delayed surgery on patients with retained intracranial missiles should be aware of the risk of spontaneous migration and verify the location of the missile after positioning the patient for surgery.