Objective Increasing construct stability of lumbosacral instrumentations using S2–ala screws as an alternate to iliac screws. Indications Revision surgery after failed lumbosacral fusion; long instrumentations to the sacrum; L5–S1 fusion without anterior support. Contraindications Lack of sacral bone stock. Surgical technique Midline approach. The entry point for S2–ala screws is caudal to the posterior S1 foramen and close to the lateral sacral crest. Screw tract preparation for S2–ala screws necessitates 30–45° angulation in the axial plane. Biplanar fluoroscopy with inlet and outlet views ensure screw accuracy. With S2–ala screws, bicortical fixation is the goal. Postoperative management Patients are mobilized under the surveillance of physiotherapists on day 1 and released from the hospital after 10 days. Clinical and radiographic controls are performed at 6, 12 and 24 months. Results Retrospective review of 80 patients undergoing S2–ala screw fixation. Main diagnosis was degenerative lumbar instability, adult scoliosis, high-grade listhesis, and nonidiopathic scoliosis. In 66% of patients, the instrumentation using S2–ala screws was part of a major lumbosacral revision surgery. Follow-up averaged 26 months. There were no deaths or major neurovascular complications. First time fusion rate at L5–S1 was greater than 90%. Eight patients (10%) experienced a complication which could be related to the S2–ala screws. Out of 160 S2-ala screws, 16 screws were judged to cause focal irritation and were removed, indicating a survival rate of 90% for the S2–ala screw.