title: Postdural disc herniation at L5/S1 level mimicking an extradural spinal tumor.
abstract: Postdural disc herniation has been documented rarely and the pathogenesis is still unknown. The average age of postdural disc herniations is between 50 and 60 years, and the sites most frequently affected by postdural lumbar disc herniations are L3-L4 and L4-L5, only less than 10 % in L5-S1. Although magnetic resonance imaging (MRI) is a useful tool in the diagnosis of this disease, the postdural disc herniation is usually misdiagnosed as extradural spine tumor preoperatively. The definitive diagnosis is made during operation or according to the postoperative pathology.
  
  
  
  In this article, we described here a 48-year-old male patient who presented with intermittent pain in the low back and frequent urination for 4 years as well as hypesthesia and pain of the left lower extremity for 1 month.
  
  
  
  A standard total laminectomy was performed and the histopathological diagnosis was consistent with a degenerated intervertebral disc. The patient presented significant relief of the pain and of the neurological symptoms, but no improvement of frequent urination, in the postoperative period.
  
  
  
  The diagnosis of postdural disc herniations is very difficult and mainly based on intraoperative and histopathological results. Early surgical intervention is important to relieve symptoms and prevent severe neurological deficits.
authors.affiliation: People's hospital of Liaocheng, 67 Dongchang West Road, Liaocheng, 252000, Shandong, China.
authors.forename: Kunpeng
authors.initials: K
authors.lastname: Li
authors.affiliation: People's hospital of Liaocheng, 67 Dongchang West Road, Liaocheng, 252000, Shandong, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li
authors.affiliation: People's hospital of Liaocheng, 67 Dongchang West Road, Liaocheng, 252000, Shandong, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Geng
authors.affiliation: People's hospital of Liaocheng, 67 Dongchang West Road, Liaocheng, 252000, Shandong, China.
authors.forename: Chenghu
authors.initials: C
authors.lastname: Wang
authors.affiliation: People's hospital of Liaocheng, 67 Dongchang West Road, Liaocheng, 252000, Shandong, China. 120882937@qq.com.
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Ma
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis* / Q000601:surgery; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000175:diagnosis*; D017116:Low Back Pain / Q000209:etiology; D008159:Lumbar Vertebrae / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012447:Sacrum / Q000473:pathology; D013125:Spinal Neoplasms / Q000175:diagnosis*
keywords: Extradural spine tumor; Intervertebral disc herniation; L5/S1 level; Postdural disc herniation