ABSTRACT: BACKGROUND: Although there is no evidence that the long-term effects of scoliosis surgery are superior to the long-term effects of Adolescent Idiopathic Scoliosis (AIS) itself, patients can fear the consequences of not under going this surgery due to incorrect or insufficient information. The main indication for surgical treatment in patients with AIS, is cosmetic. However spinal surgery may, along with other negative side effects, actually cause postoperative clinical deterioration. This complication of surgery has not yet been described in international literature. CASE PRESENTATION: A 15-year old female patient originally presenting with a well-compensated double curve pattern scoliosis. The patient was advised to undergo surgery due to the long-term negative impact of signs and symptoms of scoliosis upon her health. The patient agreed to surgery, which was performed in one of Germanys leading centres for spinal surgery. The thoracolumbar curve was corrected and fused, while the thoracic curve, clearly showing wedged vertebrae, defined as structural scoliosis, remained untreated.This operation left the patient with an unbalanced appearance, with radiological and clinical imbalance to the right. The clinical appearance of the patient though clearly deteriorated post-surgery. Furthermore, the wedged disc space below the fusion area indicates future problems with possible destabilisation accompanied probably by low back pain. CONCLUSION: Scoliosis surgery for patients with AIS is mainly indicated for cosmetic or psychological reasons. Therefore the treatment leading to the best possible clinical appearance and balance has to be chosen. Patients should be informed that surgery will not necessarily improve their health status. Clinical deterioration after surgery may occur, and such information is crucial for an adequate informed consent.