General Session: Adult Spinal Deformity-2

Presented by: J. Henry - View Audio/Video Presentation (Members Only)


M. Spiegel(1), J. Henry(1), I. Gammal(1), C. Jalai(1), E. Tanzi(1), S. Vira(1), J. Oren(1), T. Protopsaltis(1), T. Errico(1), V. Lafage(2), F. Schwab(2)

(1) NYU Hospital for Joint Diseases, Orthopedic Surgery, New York, NY, United States
(2) Hospital for Special Surgery, New York, NY, United States


Background Context: In adult spinal deformity (ASD) surgery, sagittal radiographic preoperative planning is of recognized value in achieving optimal surgical outcomes. However, whether due to intraoperative medical or mechanical reasons, it is common for surgeons to deviate from the preoperative plan and change strategy with the intention of yielding more ideal alignment outcomes. Understanding the relative importance of the surgical plan and departures from the plan is critical to maximizing success in ASD realigment surgery.

Purpose: To demonstrate that proper preoperative planning for adult spinal deformity cases leads to better outcomes irrespective of intraoperative deviations from the plan.

Study Design/Setting: Prospective database collected over years 2011 to 2014.

Patient Sample: This study is an analysis of consecutively enrolled adult patients (age over 18) with severe sagittal ASD, as measured by: pelvic incidence minus lumbar lordosis (PI-LL) ≥ 10°, pelvic tilt (PT) ≥ 20°, or sagittal vertical axis (SVA) ≥ 50mm. 71 adult patients were included in this study, with mean age 63 years, 65% female, 80% of surgical cases were revisions, and 80% of patients with at least one co-morbidity. Outcome measure: Planned and postoperative alignments were compared to Scoliosis Research Society-Schwab criteria and age-adjusted alignment ideals for PI-LL, PT, and SVA. Post-operative outcomes were categorized as under-corrected, within ideal range, or over-corrected.

Methods: Demographics and baseline radiographs were obtained. Baseline images were used for surgical planning with a validated software. Intraoperative complications and changes in surgical strategy were recorded. Radiographic, complication, and revision data were all obtained at each follow-up visit for two years.

Results: Postoperative alignment was under-corrected when compared to planning group. The PI-LL mean difference was 4.8° (p = 0.006), and the PT mean difference was 7.2° (p < 0.001). Postoperative age-adjusted ideals were reached in 50% of patientes for PI-LL, 74% of patients for PT, and 32% of patients for SVA. An acceptable execution of plan was observed in 61% of patients for PI-LL, 59% of patients for PT, and 36% of patients for SVA. Preoperative planning was the main determinant of favorable outcomes, regardless of intraoperative strategy changes. Of the 65% of patients with preoperative plans that matched their age-adjusted ideals, 63% resulted in an ideal range PI-LL, regardless of an intraoperative strategy deviation. Of the 35% of patients with preoperative plans that did not match their age-adjusted ideals, favorable outcomes were only achieved in 16% of cases, regardless of an intraoperative strategy deviation.

Conclusions: Initial preoperative planning is paramount for successful postoperaive alignment outcomes. Intraoperative deviation from plan towards a new strategy has less of a role in achieving desirable outcomes.