INTRODUCTION: Self-Expanding Metallic Stents (SEMS) are an increasingly common pulmonary procedure due to their easy flexible bronchoscopic insertion. Airway stenting offers a valuable tool for treatment of Central Airway Obstruction (CAO) secondary to malignant or benign disease. However, in patients with benign airway disease, stent complications are upward to 50%, prompting a 2005 FDA advisory emphasizing patient selection criteria. Injudicious use in non-malignant disease increases the frequency of severe early and late complications due to strut fracture, mucosal erosion, migration, or granulation tissue stenosis –requiring urgent interventional trained pulmonary expertise in SEMS extraction. In this case, we report on the inappropriate deployment and life-threatening complication of a SEMS for benign trachealmalacia and the multi-disciplinary experience of its endoscopic removal.
CASE PRESENTATION: This 69 year old male from Louisiana has “newly diagnosed” asthma with frequent intermittent wheezing symptoms for many years. Since 2001, progressive unexplained dyspnea is now limiting his activities and after a hospitalization for pneumonia an outpatient bronchoscopy shows tracheamalacia with mild tracheal stenosis. In 2004, recurrent pneumonias prompt a repeat bronchoscopy with deployment of a SEMS into the involved tracheal area. The patient symptoms improve and no further pulmonary follow-up occurs until late 2007. At this time, the patient suffers a mild acute ischemic stroke and respiratory distress while traveling in Colorado. A chest CT scan rules out pulmonary embolism but notes “airway abnormalities.” The patient is stabilized and returns to Louisiana. Referral to our interventional pulmonary program finds a patient with monophonic wheezes over the anterior chest with imaging evidence of a SEMS in the right main stem bronchus and soft tissue partially filling the stent, critically occluding the airway. Rigid bronchoscopy is performed the next day in coordination with a multi-disciplinary team including Otolaryngology and Thoracic surgeons for endoscopic SEMS extraction. The migrated, fractured, and severely granulated SEMS proves difficult to remove requiring forceful traction, bracing of the airway wall with the rigid scope, and intentional fracturing of the well-embedded barbs for piecemeal removal over several hours. Thoracotomy, loss of airway, or death does not occur, but the patient requires a temporary custom-sized silicone Y-stent post-operatively. With close outpatient follow-up, the patient has minimal airway symptoms and currently remains stent free.
DISCUSSIONS: Although the SEMS manufacturer recommends open surgical removal, an endoscopic approach is achievable only when performed under the auspices of a multi-disciplinary airway center of excellence. Life-threatening complications are real. Our SEMS extraction experience eerily matches that described by others as “like rolling spaghetti on a fork, but much more difficult and at least equally as messy.” Indications for stent removal include: high-grade obstructing granulation tissue with strut fracture and/or mucus retention, stent migration, mucus plugging, stent infection, and strut fracture with associated pain. Mean hospital duration post stent removal is 8 days. Retained stent pieces, mucosal tears with bleeding, reobstruction requiring silicone stenting, prolonged mechanical ventilation, and pneumothoraxes are the most common complications. Metallic stents are not considered first-line therapy for benign airway obstruction. In one study, 60% of patients did not require further intervention after stent extraction, implying an initial false need for SEMS deployment. Finally, primary surgical airway reconstruction as an alternative is usually not available after SEMS placement and subsequent extraction.
CONCLUSION: The FDA advisory highlights the limited role, if any, for SEMS in benign airway pathology. Besides the inherent long-term risks associated with SEMS, this case emphasizes the labor intensive, multi-disciplinary approach required for a high-risk endoscopic procedure to be successful. A scenario likely never anticipated at time of initial SEMS deployment.
DISCLOSURE: Michael Czarnecki, None.