Rod Link Reducer system in adolescent idiopathic scoliosis: a retrospective observational trial

The Rod Link Reducer (RLR) (Globus Medical, PA, USA) allows direct three-dimensional correction of the spine deformity follows the direct vertebral rotation (DVR) theories. The purpose of this retrospective study is to compare RLR with traditional correction technique (TCT) in two cohorts of patients with adolescent idiopathic scoliosis (AIS).

Fifty-four patients (M:F = 1:8) between 2018 and 2020 were included. The first group (n = 22) was treated by RLR while the second one (n = 32) by TCT. All spines were classified as per the Lenke system. Length of hospitalization, days in intensive care unit (ICU), operative time, and blood loss were recorded. SRS-30 and SF-36 questionnaires were administered pre-operative and post-operative. We collected radiological data: pre-operative and post-operative Cobb angles, coronal and sagittal balance, trunk and thoracic height.

RLR and TCT groups are homogeneous in age (p = 0.317), sex ratio (p = 0.347), and Risser stage (p = 0.222). Between both groups there was no significant statistical difference in haemoglobin value, hospitalization length, days in ICU, operative times, SF-36, SRS-30, NRS, and perceived satisfaction. RLR group shows a better improvement of correction of main thoracic (MT) curve (RLR 54.2% ± 15.9%/TCT 38.1% ± 20.4%, p = 0.031). Nevertheless, RLR group shows a worse thoracic kyphosis correction (RLR 16.82° ± 9.13°/27.12° ± 12.13°, p = 0.015).

RLR system allows a more effective MT curve correction than TCT systems, but it seems to give a hypokyphosis effect.