Ponte Osteotomies in the Surgical Treatment of Adolescent Idiopathic Scoliosis: A Systematic Review of the Literature and Meta-Analysis of Comparative Studies

Abstract

The purpose of the present paper is to assess if Ponte osteotomies (POs) allow for a better correction in adolescent idiopathic scoliosis (AIS) surgery and to investigate their safety profile. A systematic search of electronic databases was conducted. Inclusion criteria: comparative studies that reported the outcomes of AIS patients who underwent surgical correction through posterior-only approach with and without POs. Clinical and radiographic outcomes were extracted and summarized. Meta-analyses were performed to estimate the differences between patients treated with and without POs. p < 0.05 was considered significant. In total, 9 studies were included. No significant difference in thoracic kyphosis (TK) change between patients treated with and without POs was found (+3.8°; p = 0.06). Considering only hypokyphotic patients, a significant difference in TK change resulted in POs patients (+6.6°; p < 0.01), while a non-significant TK change resulted in normokyphotic patients (+0.2°; p = 0.96). No significant difference in coronal correction (2.5°; p = 0.10) was recorded. Significant estimated blood loss (EBL) (142.5 mL; p = 0.04) and surgical time (21.5 min; p = 0.04) differences were found with POs. Regarding complications rate, the meta-analysis showed a non-significant log odds ratio of 1.1 (p = 0.08) with POs. In conclusion, POs allow for the restoration of TK in hypokyphotic AIS, without a significantly greater TK change in normokyphotic patients, nor a significantly better coronal correction. Considering the significantly greater EBL and the trend toward a higher complications rate, the correct indication for POs is crucial.

The Influence of Increased Pedicle Screw Diameter and Thicker Rods on Surgical Results in Adolescents Undergoing Posterior Spinal Fusion for Idiopathic Scoliosis

“…Therefore, a stronger fixation secondary to larger diameter screws increases the corrective forces applied to the deformed spine in all three planes, allowing for increased correction in all three dimensions. However, recent studies have shown that POs may have little to no impact on the sagittal plane and may be associated with neuromonitoring complications, higher costs, and risk of readmission, without a benefit in patient-reported outcomes [34][35][36].…”

“…This higher kyphosis can be explained by the increased fixation strength of largerdiameter screws, which can maintain the contoured rod bend and thoracic curvature during rotation [34,36,57]. Matsukawa et al conducted a finite element analysis comparing the influence of the segmental screw diameter, length, and fill on construction in osteoporotic vertebrae and found that an increased screw diameter was significantly more resistant to vertebral flexion-extension loading [50].…”

“…Pedicle screw placement was performed via free-hand technique due to steps described in the literature by Suk and Lenke [29][30][31][32]. Facetectomies, pedicle screw placement, with posterior column osteotomies (Ponte), was typically performed at several levels on the apex of the curvature [33][34][35][36]. Next, two rods were measured, cut, and contoured for coronal and sagittal plane alignment.…”