title: "In situ" fusion or reduction in high-grade high dysplastic developmental spondylolisthesis (HDSS).
abstract: OBJECTIVE
  To assess if the evaluation of the spino-pelvic balance can be effective in the surgical decision making of the high-grade high dysplastic developmental spondylolisthesis (HDDS).
  
  
  METHODS
  Sixteen patients affected with high-grade HDDS (6 treated with "in situ" fusion, and 10 with reduction and fusion) were retrospectively evaluated. A clinical and radiological assessment of the deformity correction was carried out, with a minimum follow-up of 2 years. The differences between the pre- and postoperative measures were statistically analyzed using a two-tailed, paired t test.
  
  
  RESULTS
  The six patients treated with "in situ" fusion showed no statistically significant change at the last follow-up relative to pelvic tilt (PT), sacral slope (SS), and grade, while the 10 patients treated with reduction showed significant changes: PT significantly decreased following surgery, while SS and grade significantly increased.
  
  
  CONCLUSIONS
  The analysis of the spino-pelvic sagittal balance allows to identify two types of HDDS: the balanced deformities, which do not need reduction, and the unbalanced deformities, in which correction is needed.
authors.affiliation: Department of Orthopaedics, University of Ancona, via Conca 71, 60126 Ancona, Italy. moniamartin@tiscali.it
authors.forename: Monia
authors.initials: M
authors.lastname: Martiniani
authors.forename: Claudio
authors.initials: C
authors.lastname: Lamartina
authors.forename: Nicola
authors.initials: N
authors.lastname: Specchia
mesh_terms: D000293:Adolescent; D000328:Adult; D001863:Bone Screws; D015331:Cohort Studies; D017586:Diskectomy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D013168:Spondylolisthesis / Q000145:classification* / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult