[Trajectory of lumbar and sacral pedicular screws: Comparison between midline versus wiltse approach]. / Trayectoria de los tornillos pediculares lumbares y sacros: Comparación entre el abordaje por linea media versus el abordaje posterolateral tipo wiltse.

ABSTRACT

OBJECTIVES: To compare the posterolateral Wiltse approach and conventional Midline approach in short lumbosacral fusions in terms of the angle of convergence of pedicle screws. METHODS: We retrospectively reviewed computed tomography (CT) images of 76 lumbar and sacral pedicular screws that had been placed using a conventional midline approach (CA) (n = 38) and a Wiltse posterolateral approach (WA) (n = 38). All patients underwent short lumbosacral fusions from L3 to S1 for degenerative spinal disease. Screws with a bone gap >4 mm in any direction, cases with previous pedicular implants, and those with coronal plane curves >20° were excluded. RESULTS: Considering all implants, the angle of convergence was 23.3° (±15.8). The mean angulation in the WA group was 29.3° (±9.7), whereas in the CA group it was 17.2° (±0.6). This difference was statistically significant (P < 0.05). CONCLUSIONS: In short, lumbosacral fusion employing the Wiltse approach allowed placement of pedicle implants with more convergence than the conventional midline approach. The clinical relevance of this is unknown, and prospective randomized studies are needed to clarify this.