Abstract Background Severe flail chest is a life-threatening situation. The Nuss procedure is a new effective treatment for severe flail chest patients who cannot be weaned from prolonged mechanical ventilation in the last few years. However, the procedure is not suitable when there are multiple fractures in both the anterior and lateral chest walls. Here, we reported a rare case of severe flail chest in a patient who suffered multiple fractures in both the anterior and lateral chest walls in a traffic accident. Case presentation A 49-year-old patient suffered severe flail chest by a steering wheel in a traffic accident with multiple fractures in both the anterior and lateral chest walls. In the beginning, the patient was administrated with mechanical ventilation because of acute respiratory distress syndrome (ARDS) for more than 1 week. Then the patient suffered from a severe lung infection and decreased blood oxygen saturation. After a multidiscipline discussion (MDT), three rib fixation plates were first used to rebuild the stability of lateral chest walls, then two Nuss bars were inserted to eliminate paradoxical movement in the anterior chest wall. Finally, the patient recovered smoothly after the combining procedure. Conclusions Severe flail chest patients with both the anterior and lateral chest walls after trauma are in a life-threatening situation, and require an appropriate procedure to get out of danger in time. Rib fixation is an effective treatment when the fractured sites are few and the fractured area is small. The Nuss procedure is a new effective method for severe flail chest with multiple fractures in an anterior chest wall, which is also a minimally invasive and short time-consuming procedure. However, it does not suitable for the patient with multiple fractures in lateral chest walls. Combining the use of Nuss procedure and rib fixation can solve severe flail chest with multiple ribs and sternum fractures in both the anterior and lateral chest walls, and the outcome of this procedure is satisfying in the present rare case.