title: Particularities of anterior fusion in L4-L5 isthmic spondylolisthesis.
abstract: L4-L5 isthmic spondylolisthesis may be associated with lumbosacral transitional vertebrae (LSTV) and altered venous vascular anatomy. The objectives of this study were to describe the anatomical characteristics of L4-L5 ISPL and the intraoperative difficulties encountered during the approach for anterior lumbar interbody fusion (ALIF).
  
  
  
  This is a retrospective review of 20 ALIFs for L4-L5 ISPL. The anatomy of the common iliac veins confluence and the position of L4-L5 with respect to the projection of the iliac crest were analysed on CT-scan. Intraoperative difficulties were noted.
  
  
  
  A LSTV was present in 60% of cases, associated with abnormally distal positioning of L4-L5 below the projection of the iliac crest. The common iliac veins confluence was abnormally proximal compared to L4-L5. No complication was noted, even if the approach was unusually difficult in 11 cases.
  
  
  
  Anterior lumbotomies are difficult because the left common iliac vein courses transversely across the left anterolateral aspect of the L4-L5 disc and L5 vertebral body, increasing the risk of vascular injury. Those difficulties have led us to abandon lumbotomies to treat L4-L5 ISPL to favour a pure anterior approach (midline) or an exclusive posterior approach.
  
  
  
  IV (retrospective study).
authors.affiliation: Service de chirurgie orthopédique et traumatologique, Fondation hôpital Saint-Joseph, 185, rue Raymond-Losserand, 75014 Paris, France. Electronic address: pemoreau@hpsj.fr.
authors.forename: P-E
authors.initials: PE
authors.lastname: Moreau
authors.affiliation: Service de chirurgie orthopédique et traumatologique, hôpital Henri-Mondor, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil, France.
authors.forename: C-H
authors.initials: CH
authors.lastname: Flouzat-Lachaniette
authors.affiliation: Service de chirurgie orthopédique et traumatologique, centre hospitalier de Rennes, 2, rue Henri-le-Guilloux, 35000 Rennes, France.
authors.forename: J
authors.initials: J
authors.lastname: Lebhar
authors.affiliation: Hôpital Henri-Mondor, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil, France.
authors.forename: G
authors.initials: G
authors.lastname: Mirouse
authors.affiliation: Clinique Geoffroy Saint-Hilaire, 59, rue Geoffroy-Saint-Hilaire, 75005 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Poignard
authors.affiliation: Clinique Geoffroy Saint-Hilaire, 59, rue Geoffroy-Saint-Hilaire, 75005 Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Allain
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007084:Iliac Vein / Q000000981:diagnostic imaging*; D007085:Ilium / Q000000981:diagnostic imaging*; D007431:Intraoperative Complications / Q000517:prevention & control; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013123:Spinal Fusion; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Iliac vein; Intraoperative complications; Lumbosacral region; Spinal fusion; Spine; Spondylolisthesis