Posterior epidural migration of herniated disc: A case series and literature review

Posterior epidural space migration of fragment herniated discs represents a rare condition related to the spine’s anatomy and only a few cases have been reported. Radiologic differential diagnosis by epidural occupying space lesions is challenging for spinal surgeons. In order to analyze the incidence, anatomy, symptoms, and imaging that can help in differential diagnosis, management, and prognosis of posterior epidural migration of herniated disc fragments, we performed a systematic literature review of all clinical studies of posterior epidural disc fragments published to date. Moreover, we reported five clinical cases from our department, in which good outcomes were obtained after surgical decompression. We identified 108 cases of posterior epidural migration of herniated discs, 50% of patients were aged 40–59, and 82.5% were male. In 63% of cases, motor function was involved, in 56%, there was sensory loss, in 36% hyporeflexia and 37% sphincter disorders. Magnetic resonance imaging was the diagnostic imaging chosen in 78% of cases, but in 32 cases, surgeons could not make a differential diagnosis before seeing intraoperative findings. Open surgery was the treatment choice in 97% of cases, 1 case was treated with an endoscopic approach, and 3 cases reported spontaneous regression. Full recovery was described in 55% of cases, in 31% an improvement without substantial deficits, and in 14% sequelae, usually with complications related to the urinary system. Taking everything into account, open surgery is considered the best choice since surgeons are often unable to make a definitive diagnosis based solely on radiological imaging; pathological confirmation is typically required.