Silicone stent placement using a rigid bronchoscope via a tracheostoma in a patient with postpneumonectomy syndrome

Background: Silicone stents are options for airway stenosis or obstruction. Generally, silicone stent placement needs rigid bronchoscopy, but manipulation of a rigid bronchoscope has technical difficulties in some cases. The objective of this clinical case report is to highlight silicone stent placement with a rigid bronchoscope successfully achieved by changing the insertion from the mouth to the tracheostoma in a patient with postpneumonectomy syndrome. Case presentation: A 47-year-old man underwent right-side pneumonectomy 30 years previously, and he had an intubation tube inserted through a tracheostoma for 29 years to maintain the lumen for bronchial stenosis due to postpneumonectomy syndrome. A granuloma grew at the distal end of intubation tube, and he had labored breathing with stridor. Rigid bronchoscopy for silicone stent placement via the mouth failed because of airway curvature. We sequentially tried rigid bronchoscopy via the tracheostoma as an alternative, and we could easily insert the scope into the left secondary carina and place the silicone stent. Conclusion: Although strong airway curvature with tracheostomy is an uncommon situation, we succeeded silicone stent placement using a rigid bronchoscope via the tracheostoma. Insertion of a rigid bronchoscope via the tracheostoma instead of via the mouth could be an option.


Background
Postpneumonectomy syndrome (PPS) is a rare complication of dynamic airway obstruction due to mediastinal shift, which sometimes leads to fatal respiratory failure. Although the treatment for PPS has not been established, stent placement is one method for lifesaving. Generally, silicone stent placement needs rigid bronchoscopy via the mouth, but manipulation of a rigid bronchoscope has technical difficulties and needs expertise. Furthermore, insertion of a rigid bronchoscope into the peripheral left main bronchus in patients with strong airway curvature is more difficult. Herein, we report successful silicone stent placement into the left main bronchus with a rigid bronchoscope via a tracheostoma in a patient with PPS.

Case presentation
A 47-year-old man sustained a right bronchial laceration in a traffic accident and underwent right-side pneumonectomy at a former hospital 30 years previously. One year after the operation, he was transported to our hospital because of dyspnea. CT showed that the left main bronchus was stretched and pressed between the pulmonary artery and the T4-6 vertebral body, rendering the bronchus extremely stenotic, and PPS was diagnosed. Although an anterior resection of the thoracic vertebral

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General Thoracic and Cardiovascular Surgery Cases body was performed to release the bronchus, the dyspnea did not improve. A tracheostomy was performed and an intubation tube (inner diameter, 7.0 mm; length, 20 cm) was placed from the tracheostoma to the left main bronchus to retain the airway lumen. The intubation tube was exchanged every half year to prevent obstruction. Thirty years after the pneumonectomy, the patient visited the hospital with dyspnea. Bronchoscopy showed a granuloma at the distal end of the intubation tube and that the left main bronchus was barely open. The granuloma was cauterized by use of neodymium-doped yttrium aluminum garnet laser and argon plasma coagulation, but it regrew. Although mitomycin was used and radiotherapy (30 Gy/15 Fr) was performed to shrink the granuloma and keep the bronchus open, the bronchial stenosis did not improve. The patient's dyspnea continued to worsen, and he was transferred to our hospital for further treatment.
Although his oxygen saturation remained above 94% without oxygen supply, the patient had severe labored breathing with stridor, and frequent sputum suction was required. He was deemed to be at high risk of asphyxiation, so we introduced extracorporeal membrane oxygenation (ECMO). Drainage and return cannulas were inserted from the right internal jugular vein and the right femoral vein, respectively. After stabilization of blood oxygenation, the intubation tube was removed and bronchoscopy was performed, which revealed that the left bronchus was narrowed 2 cm distal from the carina over about 4 cm because of bronchomalacia, and a granuloma was detected 5 mm proximally to the secondary carina (Fig. 1). After cauterizing the granuloma with the hot biopsy forceps technique to dilate the bronchus, we tried placement of a silicone stent with rigid bronchoscopy via the mouth, but the scope could not reach the distal end of the left main bronchus owing to tracheobronchial curvature. Therefore, we tried again via the tracheostoma, and we could easily insert the scope into the left secondary carina and place the silicone stent (straight-shaped; inner diameter, 10 mm; length, 6 cm; Dumon Tube BD, Novatech, Aubagne, France) (Fig. 2). The ECMO was removed 3 days after the stent placement because frequent bronchoscopic sputum aspiration was required. Although nebulizers and expectorants for sputum were needed, the patient lived without dyspnea for 2 years after the stent placement.

Discussion
In the current case, we performed rigid bronchoscopy via a tracheostoma and easily placed a silicone stent in the left main bronchus of a patient with PPS. A rigid bronchoscope is generally inserted into the trachea and bronchus via the mouth. However, the procedure is sometimes difficult because of airway curvature, neck flexion restriction, and limited mouth opening. In such cases, several techniques of silicone stent placement via a tracheostoma without rigid bronchoscopy have been reported. Nomori et al. reported a method of filling a silicone stent in an endobronchial tube and introducing it into the stenosis site by use of a pusher [1]. Hayashi et al. reported a method of placing a modified silicone stent through a tracheostoma by use of a forceps [2]. These methods do not require a rigid bronchoscope, which makes stent transport to the peripheral bronchi easier but can be difficult to adjust the stent position. In our case, the rigid bronchoscopy could not be inserted into the peripheral left main bronchus via the mouth because of strong airway curvature owing to the upper part of the trachea being shifted to the right side. Therefore, the rigid bronchoscope was inserted through the Fig. 1 A Chest X-ray at the time of transfer to our hospital. The mediastinum was shifted to the right, and the airway from the upper trachea to the left main bronchus was steeply curved. B Bronchoscopic findings and schema of the trachea and the left bronchus. At the proximal side of the left main bronchus, the airway was barely patent during inspiration but was closed during expiration, which was caused by bronchomalacia. At the distal side of the left main bronchus, bronchial stenosis due to granuloma was revealed, but the secondary carina was intact