title: Consideration of proper operative route for interlaminar approach for percutaneous endoscopic lumbar discectomy.
abstract: BACKGROUND
  Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments of lumbar disc herniation (LDH), and has three different operative approaches. This study focused on the interlaminar approach (ILA) and investigated the appropriate operative route for this approach.
  
  
  METHODS
  ILA was performed in 41 patients with LDH. The width of the interlaminar space, LDH size, and positional relation between LDH and the corresponding nerve root were radiologically evaluated. Thirty-three LDHs were removed via the shoulder of the corresponding nerve root and eight were removed via the axilla of the corresponding nerve root and dural sac. Pre- and postoperative status were evaluated using the modified Japanese Orthopedic Association (mJOA) and numerical rating scale (NRS) scores.
  
  
  RESULTS
  The mean age was 41.5 years; there was single-level involvement, mostly at L5/S1 (33 cases). The mean recovery rate of mJOA score was 59.8% and mean pre- and postoperative NRS scores were 5.8 and 0.98, respectively. Relatively severe complications developed in three patients treated by ILA via the shoulder. There was persistent numbness in the corresponding nerve area, transient muscular weakness, and transient bladder and rectal disturbance, may be due to excessive compression of the nerve root and/or dural sac by the endoscopic sheath.
  
  
  CONCLUSIONS
  ILA can be used to treat LDH revealing an interlaminar space of ≥20 mm. The procedure is minimally invasive and effective; however, appropriate selection of an operative route is important to avoid operative complications. Particularly for large LDH, the operative route via the axilla should be considered.
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, The University of Tokyo, Tokyo, Japan;; Department of Orthopaedic Surgery, Kanto Rosai Hospital, Kawasaki, Kanagawa, Japan.
authors.forename: Juichi
authors.initials: J
authors.lastname: Tonosu
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, The University of Tokyo, Tokyo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Oshima
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan.
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Shiboi
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hayashi
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Takano
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Inanami
authors.affiliation: Department of Orthopaedics, Iwai Orthopaedic Medical Hospital, Tokyo, Japan;; Department of Orthopaedic Surgery, Inanami Spine and Joint Hospital, Tokyo, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Koga
keywords: Percutaneous endoscopic lumbar discectomy (PELD); complication; interlaminar approach (ILA); lumbar disc herniation (LDH); minimally invasive