Prospective randomized controlled comparison of posterior vs. posterior-anterior stabilization of thoracolumbar incomplete cranial burst fractures in neurological intact patients: the RASPUTHINE pilot study

Abstract

Purpose: If surgery for thoracolumbar incomplete cranial burst fractures (Magerl A3.1.1) is necessary, the ideal stabilization strategy still remains undetermined. To justify posterior-anterior stabilization, which generates higher costs and potentially higher morbidity vs. posterior-only stabilization, clinical trials with sufficient power and adequate methodology are required. This prospective randomized single-centre pilot trial was designed to enable sufficient sample-size calculation for a randomized multicentre clinical trial (RASPUTHINE).

Methods: Patients with a traumatic thoracolumbar (Th11-L2) incomplete burst fracture (Magerl A3.1.1) were randomly assigned either to the interventional group (posterior-anterior) or to the control group (posterior-only). Primary endpoint of the study was the clinical outcome measured using the Oswestry Disability Index (ODI) at 24 months. Radiological outcome was assessed as secondary endpoint by evaluation of mono- and bisegmental kyphotic angulation and monosegmental fusion.

Results: 21 patients were randomly assigned to interventional group (n = 9) or control group (n = 12). One posterior-only treated patient showed a severe initial loss of correction resulting in a crossover to additional anterior bisegmental fusion. The ODI measures at the primary study endpoint showed less but insignificant (p = 0.67) disability for the interventional group over the control group (13.3 vs. 19.3%). Comparison of preoperative bisegmental kyphosis in supine position with the bisegmental kyphosis at 24-month FU in upright position showed a worsened kyphosis for the control group (10.7° → 15.6°), whereas an improved kyphosis (11° → 8.3°) was detectable for the interventional group.

Conclusion: The results of this pilot RCT showed less disability for the posterior-anterior group linked with a significant better restoration of the sagittal profile in comparison with the posterior-only group. To detect a clinically significant difference using the ODI and assuming a 20% loss of FU rate, a total of 266 patients have to be studied in the multicentre trial.

Keywords: Incomplete burst fracture; Posterior–anterior stabilization; Randomized trial; Sample-size calculation; Thoracolumbar fracture.