Post-intubation tracheal stenoses: what is the curative yield of the interventional pulmonology procedures?

Focal non-neoplastic stenoses of the trachea are uncommon and many of these are complications of either endotracheal intubation or placement of tracheostomy tube. The pathogenesis of post-intubation tracheal stenoses (PITS) may be related to multiple factors (infection due to bacterial colonization, meccanical irritation, hypotension, gastroesophageal reflux, underlying illness), but the ischemia determined by the pressure of the endotracheal tube balloon against the tracheal wall plays the major role. It results in mucosal damage, ulceration, chondritis and leads to scarring and progressive stenosis [1, 2]. The incidence of iatrogenic airway injury have markedly decreased over the years with the use of endotracheal tubes with large volume-low pressure cuffs, but tracheal stenosis continues to be a complication of prolonged endotracheal intubation and tracheostomy. The incidence of such a complication varies in the literature from 10% to 31%, but stenoses greater than 50% of the tracheal diameter are 1-2% [3]. The stenoses may be: 1) web-like type, when the circumferential strictures of the trachea involves the mucosa for a short segment (maximum 1 cm in length), in some cases with inflammation, but without any damage of the cartilages; 2) pseudoglottic type, due to lateral fracture of cartilage consequent to tracheostomy; 3) complex type, when the strictures of the trachea is more than 1cm long and is often associated with various degrees of cartilage involvement, malacia and inflammation [4]. Finally, according to their location, PITS can be distinguished in: a) subglottic, in cases of too large tubes (frequent in womens) or in the case of the proximal anterior cricoid erosion by a high tracheostomy; b) at the stoma site after tracheostomy; c) at the site where the inflatable cuff rested; d) between the stoma and the level of the cuff (tracheal malacia); and e) at the site where the tip of the tube may impinge on the tracheal wall [5]. The management of PITS is still not well defined and no controlled randomised studies have been performed to evaluate the role of open surgery versus the bronchoscopic treatment, including bronchoscopic or balloon dilatation, laser resection and stent placement. The surgical tracheal sleeve resection is considered the definitive treatment of choice with a failure rate ranging from 5% to 15% [6, 7] and a post-operative mortality ranging from 1.8% to 5% [4]. However, several patients with PITS are in poor general conditions and are not suitable for surgery. Furthermore, there are cases with severe stenosis and consequent acute respiratory failure that require urgent bronchoscopic intervention before considering curative surgery. Based on these considerations, in 1999 Brichet et al. proposed an algorithm for the management of PITS. This was validated by the analysis of results in a series of 32 consecutive patients [4]. An initial bronchoscopic treatment was performed in all patients. In cases with “web-like stenosis” a radial incision of the fibrotic membrane by laser followed by gentle mechanical dilatation with bronchoscope was performed. This treatment was repeated up to three times in cases of recurrence, before considering surgery or stent placement for inoperable patients. The success rate of bronchoscopic treatment was 66%. In cases with complex stenosis the initial treatment was bronchoscopic dilatation followed by silicone stent placement. Six months later, the stent was removed in patients suitable for surgery and in cases of recurrence a tracheal sleeve resection was performed. In inoperable patients, after six months the stent was left in place or removed, and placed again in case of recurrence. The success rate of bronchoscopic treatment after stent removal in cases of complex stenosis was 17.6%. The low definitive curative yield of bronchoscopic procedures in cases of complex stenosis and the reported risk that a stent might lengthen the tracheal segment to be resected [4], induces to revisit this algorithm. In cases of complex stenosis, if the patient is suitable for surgery, the tracheal sleeve reMonaldi Arch Chest Dis 2007; 67: 2, 71-72.