Entrapment of a metal foreign body in the cervical spinal canal during surgical procedure: A case report

RATIONALE: Retention of foreign objects in spinal canal usually results from penetrating spinal trauma or failed internal instruments. However, entrapment of a foreign body in cervical spinal canal during surgery is rare, and whether such an object may cause neurological complications remains unknown in literature. PATIENT CONCERNS: A 50-year-old man underwent C5 corpectomy and instrumentation surgery due to cervical myelopathy. During the surgery, the cutting edge of a Kerrison rongeur was broken and the metal tip was retained behind C4 vertebra. DIAGNOSIS: Retention of foreign body in the cervical spinal canal. INTERVENTIONS: To remove the metal object, multiple strategies were tried but all failed. As such a metal object was thought to be dangerous to the spinal cord, a remedy C4 corpectomy was performed to remove it. Accidentally, however, the metal fragment further migrated to C2/3 canal. At last, the metal fragment had to be retained in the cervical spinal canal. OUTCOMES: At 2-year follow-up, the metal fragment remained in situ and no delayed complications occurred. LESSONS: We reported a rare case of metal object retention in cervical spinal canal due to rongeur fatigue fractures. Under certain circumstances, retention of a small foreign object in spinal canal may not lead to neurological complications. If failed to remove an entrapped foreign body, it may be safe to leave it in the spinal canal for further observation.