title: Lower Lumbar Segmental Arteries Can Intersect Over the Intervertebral Disc in the Oblique Lateral Interbody Fusion Approach With a Risk for Arterial Injury: Radiological Analysis of Lumbar Segmental Arteries by Using Magnetic Resonance Imaging.
abstract: METHODS
  A retrospective radiological study on vascular anatomy.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the anatomical and radiological features of lumbar segmental arteries with respect to the surgical field of the oblique lateral interbody fusion (OLIF) approach by using magnetic resonance imaging (MRI).
  
  
  BACKGROUND
  OLIF surgery restores disc height and enables indirect decompression of narrowed spinal canals through an oblique lateral approach to the spine, by using a specially designed retractor. In a minimal surgical field, injuring segmental arteries can cause massive hemorrhage.
  
  
  METHODS
  We reviewed 272 lumbar MRIs. In the sagittal images, the intersection of one-third of the anterior and median lines of the intervertebral disc (IVD) was considered the center of the virtually installed OLIF retractor. The cephalad/caudal distances from the center and branch angles of segmental arteries to the longitudinal axes of the aorta were measured to determine whether the segmental arteries run into the surgical area. Statistical significance was set at P < 0.05.
  
  
  RESULTS
  The branch angles of segmental arteries were significantly acute (≤90°) in L1-L3 arteries and significantly blunt (>90°) in L4 and L5 arteries. The average distance to the center of the caudal adjacent IVD was significantly larger, and there were generally low possibilities for the existence of segmental arteries below half of the vertebral height, where the surgeons can install fixation pins with ease and safety. Among the lumbar segmental arteries, L5 showed specific characteristics with significant deviation, a four times (4.1% vs. L1-L3 segmental arteries) higher adjacency rate, and a two-fifth (38.6% vs. 100%) lower existence rate.
  
  
  CONCLUSIONS
  Segmental arteries can be involved in the surgical field of OLIF especially in the lower lumbar spine level of L4 and L5 arteries, which can directly run across IVDs. L5 segmental arteries can also be iliolumbar arteries that have an abnormal trajectory by nature.
  
  
  METHODS
  4.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Orita
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Inage
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sainoh
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shiga
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kanamoto
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Abe
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Department of Orthopaedic Surgery, East Chiba Medical Center, Togane, Japan.
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Aoki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Matsuura
authors.affiliation: Department of Bioenvironmental Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Takane
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Kubota
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yawara
authors.initials: Y
authors.lastname: Eguchi
authors.affiliation: Department of Orthopaedic Surgery, Shimoshizu National Hospital, Yotsukaido, Japan.|Kitachiba Spine and Sports Clinic, Chiba, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Terakado
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000293:injuries*; D019299:Decompression, Surgical / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000601:surgery*; D008161:Lumbosacral Region / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011859:Radiography / Q000379:methods; D012189:Retrospective Studies; D012306:Risk; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods; D057772:Vascular System Injuries / Q000209:etiology* / Q000601:surgery; D055815:Young Adult