#368 Minimally Invasive Treatment of Adult Scoliosis with XLIF a Report of Clinical and Radiographic Outcomes from a Prospective Multicenter Study

General Session: Lateral Interbody Fusion

Presented by: R.E. Isaacs


F.M. Phillips (1)
W.B. Rodgers (2)
A. Tohmeh (3)
R.E. Isaacs (4)
SOLAS Degenerative Study Group

(1) Rush University Medical Center, Chicago, IL, USA
(2) Midwest Orthopaedic, Jefferson City, MO, USA
(3) Northwest Orthopaedic Specialists, Spokane, WA, USA
(4) Duke University, Surgery/Neurosurgery, Durham, NC, USA


Background: XLIF as a stand-alone procedure has the advantage of avoiding a secondary posterior surgery in elderly/comorbid populations. The degree of deformity correction achievable with XLIF with or without posterior fixation is not well documented. This report examines clinical and radiographic outcomes of adult degenerative scoliosis patients treated with lateral interbody fusion.

Methods: 107 adult scoliosis patients were treated with XLIF. Radiographs and clinical outcomes were collected preoperatively and at 0.5, 3, 6, 12, and 24 months. Radiographic measures include lordosis (L1- S1), coronal Cobb, subsidence and migration. Neurologic evaluation and Oswestry disability index (ODI), visual outcomes scores (VAS), SF-36, and satisfaction were collected at all visits.

Results: Average age was 68 years. Mean Charlson co-morbidity score was 0.48. On average 4.4 levels (range 1-9) were treated per patient with anterior and/or posterior fixation. Supplemental fixation by patient included bilateral (50%) or unilateral (26%) pedicle screws, or anterolateral plating (7%); 17% were stand-alone. All unilateral screws were placed percutaneously. Bilateral screws were placed percutaneously (44%) or via open technique (56%). Mean operative time was 178min and median blood loss was 100-200mL. Mean hospital stay was 3.8 days (2.9 unstaged, 8.1 staged). Of 34 motor and 20 and sensory deficits identified pre-operatively, 26 motor and 18 sensory improved after surgery. New and persistent post-surgical deficits were identified in 7 patients. Clinical outcomes were improved (p< 0.05) from baseline to 24mo (Figure 1). 85% of patients were satisfied with their procedure.

Cobb correction was greatest in XLIF patients with bilateral pedicle fixation (12°, 46%). Pre- to postoperative Cobb correction was achieved in all scenarios. In patients with bilateral screws, Cobb measures were maintained from post-op to 24mo (p=0.385). In patients with standalone constructs Cobb correction was not maintained from post-op to 24mo (post:15°, 12mo:19°, p=0.025).

36 patients were hypolordotic (L1-S1 lordosis >-40°) at baseline. In hypolordotic patients, lordosis improved from an average of -28° to -37° after XLIF (p< 0.001), and an average of -34° at 24mo. Correction loss at 24mo was significant (p=0.024). 24mo disc height was influenced by supplemental fixation (p=0.005), with the smallest disc height in stand-alone segments and the greatest in patients with bilateral fixation.

Conclusion: Despite advanced age and co-morbidities, clinical outcomes from this study reflect promising outcomes, low revision rates, and high patient satisfaction. Supplemental fixation; specifically bilateral screws, optimized coronal plane deformity correction and reduced disc height loss after XLIF. This prospective study supports XLIF as a valuable adjunct in the treatment of adult scoliosis.