title: Reliability and scientific use of a surgical planning software for anterior cervical discectomy and fusion (ACDF).
abstract: Software-based planning of a spinal implant inheres in the promise of precision and superior results. The purpose of the study was to analyze the measurement reliability, prognostic value, and scientific use of a surgical planning software in patients receiving anterior cervical discectomy and fusion (ACDF).
  
  
  
  Lateral neutral, flexion, and extension radiographs of patients receiving tailored cages as suggested by the planning software were available for analysis. Differences of vertebral wedging angles and segmental height of all cervical segments were determined at different timepoints using intraclass correlation coefficients (ICC). Cervical lordosis (C2/C7), segmental heights, global, and segmental range of motion (ROM) were determined at different timepoints. Clinical and radiological variables were correlated 12 months after surgery.
  
  
  
  282 radiographs of 35 patients with a mean age of 53.1 ± 12.0 years were analyzed. Measurement of segmental height was highly accurate with an ICC near to 1, but angle measurements showed low ICC values. Likewise, the ICCs of the prognosticated values were low. Postoperatively, there was a significant decrease of segmental height (p < 0.0001) and loss of C2/C7 ROM (p = 0.036). ROM of unfused segments also significantly decreased (p = 0.016). High NDI was associated with low subsidence rates.
  
  
  
  The surgical planning software showed high accuracy in the measurement of height differences and lower accuracy values with angle measurements. Both the prognosticated height and angle values were arbitrary. Global ROM, ROM of the fused and intact segments, is restricted after ACDF.
authors.affiliation: Department of Neurosurgery, Knappschafts-Krankenhaus Bochum, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany. martin.barth@kk-bochum.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Barth
authors.affiliation: Department of Medical Statistics, University Medicine Mannheim, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
authors.forename: Christel
authors.initials: C
authors.lastname: Weiß
authors.affiliation: Department of Neurosurgery, Knappschafts-Krankenhaus Bochum, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Brenke
authors.affiliation: Department of Neurosurgery, Knappschafts-Krankenhaus Bochum, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Schmieder
mesh_terms: D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D017586:Diskectomy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012984:Software; D013123:Spinal Fusion / Q000379:methods*; D025321:Surgery, Computer-Assisted; D064232:Visual Analog Scale
keywords: ACDF; Cervical spine; Discectomy; Surgical planning software