Introduction: Surgery in idiopathic scoliosis consists of triplanar deformity correction with simultaneous reconstruction of normal sagittal spinal alignment. Aim: evaluation of spinal alignment in sagittal plane in patients with lumbar scoliosis, before and after modified anterior “bone-on-bone” fusion according to Gaines. Material and methods: 23 patients with structural lumbar curve underwent anterior “bone-on-bone” fusion. Average lumbar curve angle was 61.0o, and thoracic angle was 45.3o. We assessed the proceedings of surgery, extent of fusion, and we analyzed the spinal alignment after operations. Mean follow up period was 2 years. Results: Mean extent of fusion was 4.4 vertebra. The mean thoracic kyphosis was 24.3o after operation and 21.3o at control examination. The mean lumbar lordosis was 22.6o after surgery and 22.2o at control examination. The mean Th10-L2 angle, kyphotic after surgery, was 18.1o and did not change during follow up. Only in the group of 4 patients with double intervertebral cages, Th10- L2 angle decreased after surgery from 15.5o to 8.5o and 9o after follow up period. Conclusion: Anterior fusion with two intervertebral cages in lumbar spine allows proper reconstruction of sagittal balance.