title: Intradural disc herniation: radiographic findings and surgical results with a literature review.
abstract: OBJECTIVE
  To report a series of four cases of intradural disc herniation (IDH) with a review of the literature.
  
  
  BACKGROUND
  IDH is a rare type of disc herniation. Preoperative diagnosis is difficult and IDH is only confirmed during surgery in most cases. Here, we describe four cases of IDH, including three with lumbar hernia and one with thoracic hernia.
  
  
  METHODS
  A retrospective chart review, surgical database query, and review of radiology reports are presented for each case, along with a literature review of IDH.
  
  
  RESULTS
  Two of the four patients had a history of surgery at the same spinal level. Ring enhancement in gadolinium-enhanced MRI, an air image in computed tomography, and complete block in myelography were observed in the series. Surgery was performed with a transdural approach in all patients. One patient underwent transforaminal lumbar interbody fusion after postoperative recurrence. Three patients with lumbar involvement had nerve root symptoms preoperatively, but showed symptomatic improvement in the early postoperative period. In contrast, the patient with thoracic involvement had preoperative muscle weakness due to myelopathy symptoms, and had residual symptoms after surgery.
  
  
  CONCLUSIONS
  IDH is a rare disease and characteristic imaging findings can be useful for diagnosis. Intraoperative findings lead to a definitive diagnosis in many cases and recognition of the pathological characteristics of IDH is important.
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan. Electronic address: imagama@med.nagoya-u.ac.jp.
authors.forename: Shiro
authors.initials: S
authors.lastname: Imagama
authors.affiliation: Department of Orthopaedic Surgery, Kariya Toyota General Hospital, 15, Sumiyoshi-cho, Kariyashi, Aichi 448-8505, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsubara
authors.affiliation: Department of Orthopaedic Surgery, Toyohashi Municipal Hospital, 50, Hakkennishi, Aotakecho-aza, Toyohashi, Aichi 441-8570, Japan.
authors.forename: Hisatake
authors.initials: H
authors.lastname: Yoshihara
authors.affiliation: Department of Orthopaedic Surgery, Japanese Red Cross Nagoya Daiichi Hospital, 3-35, Michishita-cho, Nakamura-ku, Nagoya 453-8511, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Zenya
authors.initials: Z
authors.lastname: Ito
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ando
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Ukai
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Muramoto
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Shinjo
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakashima
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004388:Dura Mater / Q000601:surgery*; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods; D016896:Treatment Outcome
keywords: Intradural disc herniation; Preoperative diagnosis; Re-operation; Spinal surgery