title: Validation and analysis of a multi-site MIS Prospective Registry through sub-analysis of an MIS TLIF Subgroup.
abstract: METHODS
  Retrospective analysis of multi-site, prospectively collected database.
  
  
  OBJECTIVE
  To assess the validity and utility of a prospective spine registry by sub-analysis of patients treated with MIS TLIF.
  
  
  BACKGROUND
  The MIS registry is a large-scale, multi-center series of prospectively collected clinical information on outcomes, complications, and adverse events for minimally invasive spine procedures for the treatment of degenerative lumbar conditions.
  
  
  METHODS
  Analysis was performed on the MIS Prospective Registry database. A subgroup of patients treated by MIS TLIF technique was identified. Statistical analyses were performed on pre and post-operative data collected using validated health related quality of life outcome tools. Missing 1-year patient follow-up data was obtained through progressive correspondence modalities.
  
  
  RESULTS
  Data analysis was performed on 98 MIS TLIF patients (56 female, 42 male) with a median age of 64.5 years (range 25-91 years) which were extracted from a total registry population of 478 patients. The one year follow-up rate was 87%. A total of 64 single-level, 23 two-level, 3 three-level, and 3 combined TLIFs staged with an MIS lateral procedure were included. The primary surgical indications were spondylolisthesis (27%), central stenosis (25%), foraminal stenosis (14%), post-laminectomy syndrome (14%) and degenerative scoliosis (6%). The peri-operative blood transfusion rate was 3%. Complications included intraoperative dural tear (n = 3), deep wound infection (n = 2), superficial dehiscence/cellulitis (n = 2). There was a 4% re-operation rate at the 1 year post-operative time point. Half of patients were discharged within 2 days (range 1-11 days, mean 2.97 days, median 2 days). All patients that were discharged on the first post-operative day (n = 14) underwent a single-level MIS TLIF procedure and had significantly lower pre-op disability index score than those discharged on POD 3-5 (43.7 ± 15.5 vs. 56.0 ± 18.3, p = 0.04). Average ODI scores in the subgroup of patients that had reached the one year postoperative time point were 46.5 pre-op (n = 46), and 26.2 at 1 year post-op (n = 40, p = 0.0001). There was significant improvement in VAS scores: pre-operative (back = 6.7, leg = 5.4, n = 46), and 1 year post-operative (back = 3.2, leg = 1.7, n = 40, p = 0.0001). Patients with pre-operative ODI scores greater than 50 demonstrated significant improvement starting at the 6 week post-operative time point (24 point improvement, n = 46, p < 0.001). A pre-operative ODI between 35-50 showed significant improvement starting at 3 months (15.5 point improvement, n = 29, p = 0.05). Patients with a pre-operative ODI score less than 35 had an initial period of increased disability with a trend towards significant improvement by 3 months post-op (n = 20).
  
  
  CONCLUSIONS
  Initial findings of the MIS Prospective Registry show patients can be enrolled in a relatively short time period and patient based questionnaires can successfully be obtained through a combination of clinic follow-up appointments and remote correspondence. Outcomes of the MIS Registry MIS TLIF subgroup were consistent with previously published MIS TLIF studies. Sub-analysis of data collected through level-specific patient diagnosis and treatment modalities permits outcome analysis of a wide breadth of spinal conditions and interventions.
authors.affiliation: Spine Institute of San Diego, Minimally Invasive Spine Center of Excellence.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Sclafani
authors.affiliation: Spine Institute of San Diego, Minimally Invasive Spine Center of Excellence.
authors.forename: Kamshad
authors.initials: K
authors.lastname: Raiszadeh
authors.affiliation: Spine Institute of San Diego, Minimally Invasive Spine Center of Excellence.
authors.forename: Ramin
authors.initials: R
authors.lastname: Raiszadeh
authors.affiliation: Spine Institute of San Diego, Minimally Invasive Spine Center of Excellence.
authors.forename: Paul
authors.initials: P
authors.lastname: Kim
authors.affiliation: Spine & Orthopedic Specialists, PLLC.
authors.forename: Todd
authors.initials: T
authors.lastname: Doerr
authors.affiliation: Trinity Spine Center.
authors.forename: Farhan
authors.initials: F
authors.lastname: Siddiqi
authors.affiliation: Midland Orthopaedics.
authors.forename: Ivan
authors.initials: I
authors.lastname: LaMotta
authors.affiliation: University of Michigan.
authors.forename: Paul
authors.initials: P
authors.lastname: Park
authors.affiliation: Hinsdale Orthopaedics.
authors.forename: Cary
authors.initials: C
authors.lastname: Templin
authors.affiliation: Milestone Research Organization.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Gill
authors.affiliation: Milestone Research Organization.
authors.forename: Kevin
authors.initials: K
authors.lastname: Liang
authors.affiliation: Spine Institute of San Diego, Minimally Invasive Spine Center of Excellence.
authors.forename: Choll W
authors.initials: CW
authors.lastname: Kim
keywords: MIS TLIF; Registry; clinical outcome; complications; minimally invasive spine surgery