title: The Oblique Anterolateral Approach to the Lumbar Spine Provides Access to the Lumbar Spine With Few Early Complications.
abstract: BACKGROUND
  During the last 20 years several less-invasive anterior approaches to the lumbar spine have become standard, including the extreme lateral transpsoas approach. Although it is associated with a lower risk of vascular injury compared with anterior midline approaches, neuromonitoring is considered mandatory to avoid neurologic complications. Interestingly, despite neuromonitoring, the reported risk of neurologic deficits with the extreme lateral transpsoas approach is greater than observed with other anterior approaches. An alternative lateral, oblique, psoas-sparing approach, recently named the oblique lumbar interbody fusion, uses the anatomic pathway between the abdominal vessels anteriorly and the lumbar plexus laterally to decrease the risk of neurologic and vascular injury; however, as yet, little on this new approach has been reported.
  
  
  OBJECTIVE
  We asked: what proportion of patients experienced (1) perioperative complications (overall complications), (2) vascular complications, and (3) neurologic complications after less-invasive anterior lumbar interbody fusion through the oblique lumbar interbody approach at one high-volume center?
  
  
  METHODS
  We performed a chart review of intra- and perioperative complications of all patients who had undergone minimally invasive anterior lumbar interbody fusion through a lateral psoas-sparing approach from L1 to L5 during a 12-year period (1998-2010). During the study period, the oblique, psoas-sparing approach was the preferred approach of the participating surgeons in this study, and it was performed in 812 patients, all of whom are studied here, and all of whom have complete data for assessment of the short-term (inpatient-only) complications that we studied. In general, we performed this approach whenever possible, although it generally was avoided when a patient previously had undergone an open retro- or transperitoneal abdominal procedure, or previous implantation of hernia mesh in the abdomen. During the study period, posterior fusion techniques were used in an additional 573 patients instead of the oblique lumbar interbody fusion when we needed to decompress the spinal canal beyond what is possible through the anterior approach. In case of spinal stenosis calling for fusion in combination with a high disc space, severe endplate irregularity, or severe biomechanical instability, we combined posterior decompression with oblique lumbar interbody fusion in 367 patients. Complications were evaluated by an independent observer who was not involved in the decision-making process, the operative procedure, nor the postoperative care by reviewing the inpatient records and operative notes.
  
  
  RESULTS
  A total of 3.7% (30/812) of patients who underwent the oblique lumbar interbody fusion experienced a complication intraoperatively or during the hospital stay. During the early postoperative period there were two superficial (0.24%) and three deep (0.37%) wound infections and five superficial (0.62%) and six deep (0.86%) hematomas. There were no abdominal injuries or urologic injuries. The percentage of vascular complications was 0.37% (n = 3). The percentage of neurologic complications was 0.37% (n = 3).
  
  
  CONCLUSIONS
  The risk of vascular complications after oblique lumbar interbody fusion seems to be lower compared with reported risk for anterior midline approaches, and the risk of neurologic complications after oblique lumbar interbody fusion seems to be lower than what has been reported with the extreme lateral transpsoas approach; however, we caution readers that head-to-head studies will need to be performed to confirm our very preliminary comparisons and results with the oblique psoas-sparing approach. Similarly, future studies will need to evaluate this approach in terms of later-presenting complications, such as infection and pseudarthrosis formation, which could not be assessed using this inpatient-only approach. Nevertheless, with the results of this study the oblique psoas-sparing approach can be described as a less-invasive alternative for anterior lumbar fusion surgery from L1 to L5 with a low risk of vascular and neurologic damage and without costly intraoperative neuromonitoring tools.
  
  
  METHODS
  Level IV, therapeutic study.
authors.affiliation: Spine Center, Schön Klinik München Harlaching, Harlachinger Strasse 51, 81547, Munich, Germany. cmehren@schoen-kliniken.de.|Academic Teaching Hospital and Spine Research Institute, Paracelsus Private Medical University Salzburg, Salzburg, Austria. cmehren@schoen-kliniken.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Mehren
authors.affiliation: Spine Center, Schön Klinik München Harlaching, Harlachinger Strasse 51, 81547, Munich, Germany.|Academic Teaching Hospital and Spine Research Institute, Paracelsus Private Medical University Salzburg, Salzburg, Austria.
authors.forename: H Michael
authors.initials: HM
authors.lastname: Mayer
authors.affiliation: Academic Teaching Hospital and Spine Research Institute, Paracelsus Private Medical University Salzburg, Salzburg, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Zandanell
authors.affiliation: Spine Center, Schön Klinik München Harlaching, Harlachinger Strasse 51, 81547, Munich, Germany.|Academic Teaching Hospital and Spine Research Institute, Paracelsus Private Medical University Salzburg, Salzburg, Austria.
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Siepe
authors.affiliation: Spine Center, Schön Klinik München Harlaching, Harlachinger Strasse 51, 81547, Munich, Germany.|Academic Teaching Hospital and Spine Research Institute, Paracelsus Private Medical University Salzburg, Salzburg, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Korge
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D019299:Decompression, Surgical / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005858:Germany; D061847:Hospitals, High-Volume; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D059348:Peripheral Nerve Injuries / Q000209:etiology; D016658:Psoas Muscles / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D013530:Surgical Wound Infection / Q000209:etiology; D013997:Time Factors; D016896:Treatment Outcome; D057772:Vascular System Injuries / Q000209:etiology; D055815:Young Adult