title: Changes in spino-pelvic alignment after surgical treatment of high-grade isthmic spondylolisthesis by a posterior approach: a report of 41 cases.
abstract: OBJECTIVE
  To analyze changes in spino-pelvic parameters (SPPs) after surgery of high-grade lumbar isthmic spondylolisthesis (HDIS).
  
  
  METHODS
  We analyzed 41 patients affected by HDIS operated upon by attempt of reduction and posterior spinal fusion with pedicle screw systems with or without interbody fusion. Pelvic tilt (PT), lumbar lordosis (LL), pelvic incidence (PI), and sacral slope (SS) were measured, and patients were further divided into balanced and unbalanced pelvis subgroups.
  
  
  RESULTS
  SS passed from 46.8° ± 9.8° preoperatively to 50.1° ± 10.1° (p = 0.02). PT passed from 26.7° ± 6.7° preoperatively to 22.9° ± 7.5° (p = 0.003). Unbalanced patients showed significantly higher PT and lower SS compared to the balanced patients preoperatively, and these corrected after surgery. Patients with instrumentation failure (n = 5) had significant increase in PT values postoperatively (p = 0.018).
  
  
  CONCLUSIONS
  We confirmed the positive effect of surgery on the SPPs in patients affected by HDIS, which showed different patterns of corrections with surgery for balanced and unbalanced pelvis patients.
authors.affiliation: Department of General Orthopaedics, Department Rizzoli Sicilia, Istituto Ortopedico Rizzoli di Bologna, University of Bologna, Bologna, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Faldini
authors.forename: Alberto
authors.initials: A
authors.lastname: Di Martino
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Perna
authors.forename: Kostantinos
authors.initials: K
authors.lastname: Martikos
authors.forename: Tiziana
authors.initials: T
authors.lastname: Greggi
authors.forename: Sandro
authors.initials: S
authors.lastname: Giannini
mesh_terms: D017760:Bone Malalignment / Q000000981:diagnostic imaging; D002648:Child; D006801:Humans; D010388:Pelvis / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery*; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D055815:Young Adult