Minimally invasive surgery for sternal and bilateral rib fractures

Abstract

Sternal bone fractures with bilateral multiple rib fractures cause serious instability of the anterior chest wall, and prolonged mechanical ventilation may be required. A 45-year-old man was injured in a motor vehicle collision. He suffered from a bilateral flail chest injury accompanied by a transverse sternal fracture. Minimally invasive surgical stabilisation of the anterior chest wall was performed using two bars as per the Nuss procedure. Two days after surgery, he was extubated from artificial respiration and was ultimately discharged without any complications.

Introduction

Sternal bone fractures are occasionally accompanied by multiple bilateral rib fractures. This type of chest-wall injury causes serious instability of the anterior chest wall and may necessitate prolonged mechanical ventilation and tracheostomy in many cases. Surgical stabilisation is considered to reduce the period required for mechanical ventilation, which is associated with an increased mortality rate due to pneumonia. We performed minimally invasive surgical stabilisation using two rods at an early stage and obtained a favourable outcome.

Case report

A 45-year-old man was injured when his motor truck crashed into a 10-ton motor truck waiting at some traffic lights. Part of his body, from the chest down, was wedged between the seat and handle. On arrival at our hospital, he had severe chest pain and dyspnoea with paradoxical respiration. Emergency chest radiographs revealed subcutaneous emphysema and left pneumothorax. After chest tube insertion, a computed tomography (CT) scan of the chest (Figure 1) revealed a depressed anterior chest wall, subcutaneous and mediastinal emphysema and left pulmonary contusion. Three-dimensional reconstruction of the CT of the bony thorax (Figure 2(a)) showed fractures of the left second to sixth ribs, right first to the fifth ribs and the sternum. The preliminary diagnosis was that of bilateral flail chest accompanied by a transverse fracture of the sternal body. Because he was haemodynamically stable without brain or intraperitoneal damage, surgical fixation of the anterior chest wall was considered at an early stage. Based on the Nuss procedure, two rods were inserted at the second and the third intercostal sites, without thoracoscopic support, according to the preoperative planning from the three-dimensional CT findings, and through the retro-sternum in a manner that fractured the sternal bone was interleaved (Figure 2(b)). The rods were anchored lateral to the rib fractures on either side (Figure 3). The surgical time was 86 minutes, and artificial respiration was discontinued two days after surgery. Pain was well controlled, and the patient was able to bring up sputum by himself. On day 20, he was discharged, and the rods were removed on day 191. The patient was followed up for 680 days after the removal of the rods, and no fracture recurrence was observed. He was able to return to the level of physical activity that he had before the accident.

Figure 1.

Chest computed tomography (CT) scan showing the depressed anterior chest wall, left lung contusion, subcutaneous emphysema and mediastinal emphysema.

Figure 2.

(a) Bony thorax: three-dimensional reconstruction of the CT scan. Multiple fractures are present on the left (second through sixth) and right (first through fifth) ribs and the sternal body. (b) Two rods were inserted at the second and the third intercostal site through the retro-sternum.

Figure 3.

Postoperative plain chest radiograph.

Discussion

Flail chest is a severe chest-wall injury that disturbs respiratory movement and may require prolonged mechanical ventilation. Surgical stabilisation is considered to reduce the period required for mechanical ventilation. In 1998, Nuss reported a less invasive surgical method for funnel chest cases, mainly in paediatric patients, in which bars were inserted to lift the sternum and to stabilise the chest wall. ¹ Since 1999, we have applied the Nuss procedure to treat flail chest, without thoracoscopic support, in 11 cases. The insertion of a rod under the least stable flail segments, which remain in the bilateral chest wall, fixes the injured chest wall to the residual wall instead of to the injured ribs. The insertion of a bar is safer and less complicated in funnel chest cases, even without videoscope support. However, prolonged pulmonary fistula and complicated blunt chest trauma are the potential risks of intrathoracic infection of a bar.

As a result, we have observed good outcomes, such as a reduction in the duration of mechanical ventilation.^2,3 A sternal fracture, in addition to flail chest, worsens the instability of the chest wall, making surgical repair essential. ⁴ In a previous case, we experienced a transverse sternal fracture accompanied by a unilateral flail chest. ² We performed a wire fixation for the sternal fracture first. However, the stability of the chest wall was inadequate. The following day, we then performed a further operation using the Nuss procedure with one bar. From our experience, in sternal fractures complicated by a flail chest, sternal stabilisation on its own is not adequate, and simultaneous repair of the ribs and the sternum must be considered. Moreover, in cases such as the present case, a more complex instability may develop. ⁴ There are several reports on external fixation methods ⁴ in which each rib in the injured thoracic cage is repaired individually. However, in our case, where multiple ribs had to be repaired at the same time, more invasive and complicated surgical procedures would have been required. In this procedure, the insertion site of the two rods was determined before surgery according to 3D-CT findings, and only four small (3 cm) bilateral chest incisions were made. The two rods were placed posterior to the sternum, with one on either side of the sternal fracture in order to prevent further displacement of the sternum when the sternal fracture was reduced. These resulted in a shorter surgical time and less soft-tissue injury. Lifting the entire anterior chest wall is effective in reducing movement and close apposition of the ends of the rib without significant displacement (Figure 2). We observed that compared to insertion of one rod, inserting two rods enabled a wider range of the flail segment to be firmly fixed. Less invasive procedures are more important during the acute phase of the trauma surgery, even if the process entails further surgery to remove the rods. The rods were left in situ for more than six months according to the patient’s convenience in this case. We consider that indwelling rods are adequate for three to four months. ²

In conclusion, the Nuss procedure using two rods can be expected to manage sternal fractures accompanied by multiple bilateral rib fractures.