title: Comparison of open and minimally invasive techniques for posterior lumbar instrumentation and fusion after open anterior lumbar interbody fusion.
abstract: BACKGROUND
  Minimally invasive techniques for spinal fusion have theoretical advantages for the reduction of iatrogenic injury. Although this topic has been investigated previously for posterior-only interbody surgery, such as transforaminal lumbar interbody fusion, similar studies have not evaluated these techniques after anteroposterior spinal fusion, a study design that can more accurately determine the effect of pedicle screw placement and decompression via a minimally invasive technique without the confounding effect of simultaneous interbody cage placement.
  
  
  OBJECTIVE
  To compare process measures that provide insight into the morbidity of surgery, such as surgical time and the length of postoperative hospital stay between open and minimally invasive anteroposterior lumbar fusion; and to compare the complications during the intraoperative and early postoperative period between open and minimally invasive anteroposterior lumbar fusion.
  
  
  METHODS
  Retrospective case-control study.
  
  
  METHODS
  One hundred sixty-two patients.
  
  
  METHODS
  Estimated blood loss, length of surgery, intraoperative fluoroscopy time, length of postoperative hospital stay, malpositioned instrumentation on postoperative imaging, and postoperative complications, including pulmonary embolus and surgical site infection.
  
  
  METHODS
  Patients who underwent open anterior lumbar interbody fusion followed by either traditional open posterior fusion (Open group) or minimally invasive posterior fusion (minimally invasive surgery [MIS] group) were matched by the number of surgical levels. A chart review was performed to document the intraoperative and postoperative process measures and associated complications in the two groups. Secondary analyses were performed to compare the subgroups of patients, who did and did not undergo a posterior decompression at the time of posterior instrumentation to determine the effect of decompression.
  
  
  RESULTS
  Baseline characteristics were similar between the Open and MIS groups. Estimated blood loss and postoperative transfusion rate were significantly higher in the Open group, differences that the subanalyses suggested were largely because of those patients who underwent concomitant decompression. Length of stay was not significantly different between the groups but was significantly shorter for MIS patients treated without decompression than for Open patients treated without decompression. Intraoperative fluoroscopy time was significantly longer in the MIS group. There was no difference in the infection or complication rates between the groups.
  
  
  CONCLUSIONS
  Our case-control study comparing patients who underwent anterior lumbar interbody fusion followed by open posterior instrumentation with those who underwent anterior lumbar interbody fusion followed by minimally invasive posterior instrumentation demonstrated that patients undergoing MIS fusion without decompression had less blood loss, less need for transfusion in the perioperative period, and a shorter hospital stay. In contrast, most outcome measures were similar between MIS and Open groups for patients who underwent decompression.
authors.affiliation: Department of Orthopaedic Surgery, Rothman Institute, Thomas Jefferson University, 1015 Walnut St, Philadelphia, PA 19107, USA. chris.kepler@gmail.com
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Kepler
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Yu
authors.forename: Jordan A
authors.initials: JA
authors.lastname: Gruskay
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Delasotta
authors.forename: Kristen E
authors.initials: KE
authors.lastname: Radcliff
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Rihn
authors.forename: Alan S
authors.initials: AS
authors.lastname: Hilibrand
authors.forename: D Greg
authors.initials: DG
authors.lastname: Anderson
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007902:Length of Stay; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000009:adverse effects* / Q000379:methods*