Table 1

Summary of inclusion and exclusion criteria.

Variable(s)Inclusion CriteriaExclusion Criteria
Patient FactorsAdult patients with back and/or leg pain who underwent surgery for the following degenerative conditions:

  • Lumbar stenosis

  • Lumbar radiculopathy

  • Spondylolisthesis

Aged <18 yTumorInfectionCervical or thoracic spinal surgeryFracture/traumaRevision surgeryScoliosisSpinal injections
MASa Single-level or multilevel posterior MAS including

  • Laminectomy (any type)

  • Microdiscectomy

  • TLIF

  • PLIF

Cervical or thoracic surgeryAnterior or lateral lumbar surgeryComputer-assisted or robotic surgeryKyphoplasty or vertebroplasty
Conventional (open) surgeryOpen posterior spinal procedures including

  • Laminectomy (any type)

  • Microdiscectomy

  • TLIF

  • PLIF

Comparisons of 2 MAS proceduresCervical or thoracic surgeryAnterior or lateral lumbar surgery
OutcomesCosts analysis onlyIncremental cost-effectiveness ratio (or similar cost-effectiveness metric)Both open and MAS approach both analyzed for cost and/or outcomesDifferences in clinical outcomes only without cost analysisUtilities onlyProcedural costs not included
Study typeFull economic studies (cost-utility, cost-effectiveness, cost-benefit, cost-minimization)Cost studies (retrospective cohorts, nonrandomized prospective cohorts, decision model analyses)Studies with <10 patients per treatment armSystematic reviews
Publication typeStudies published in EnglishPeer-reviewed journalsSingle-center reports of multicenter studiesMeeting abstracts, editorials, opinion piecesBiomechanical studies, radiographic studies, animal studies, case reports, methodologies

  • aMAS was conducted through a tube using cylindrical soft tissue retractors in 16 studies. In one case, MAS was conducted endoscopically and compared with a conventional open approach.

  • Abbreviations: MAS, minimal access surgery; PLIF, posterior lumbar interbody fusion; TLIF, transforaminal lumbar interbody fusion.