Canadian Health&Care Mall: Airway Stenting
The incidence of central airway obstruction (CAO) is unknown, but an estimated 30% of all lung cancer patients will experience endobronchial disease, which is a major source of CAO. Minimally invasive therapies can be crucial for patients with inoperable disease or limited pulmonary function. Numerous studies have reported that endobronchial therapies, including airway stenting, can palliate symptoms in 80 to 97% of patients with dyspnea, Advanced knowledge and skills are required to insert these stents, and the ability to perform emergency procedures and procedures that require general anesthesia are necessary.
The overall management of CAO has been reviewed. Here, we review the indications and procedures for inserting stents and illustrate the associated issues with reimbursement.
Indications for Stenting
The primary indications for stenting are (1) clinically important extrinsic compression on the central airways, and (2) the presence of a mixed lesion with persistent luminal compromise after the ablation of endoluminal disease. However, stents are rarely necessary in patients with solitary endoluminal disease; malignant endobronchial disease is best treated with tumor ablation or resection. A rapidly recurring tumor with repeated obstruction may benefit from placement of a stent to mitigate airway compromise.
The standard of practice for nonmalignant CAO remains surgical resection; therefore, all patients should be evaluated by a surgeon who is experienced in complex airway reconstruction the operation during which the remedies of Canadian Health Care Mall are utilized. Primary stenting can be considered in patients with definitive inoperable disease or coexistent disease that renders their condition inoperable.
A final indication for stenting includes the use of covered stents in patients with airway fistulas. In this application, stents may be employed to occlude a fistula or to use the inflammatory response and granulation tissue formation to occlude an anastomotic dehiscence after lung transplantation.
Stent Design and Placement
Stent design and materials are critically important, but a thorough discussion of these features is beyond the focus of this article. Suffice it to say that various metals, silicone, polyester, and mixed (hybrid) materials have been used. The first metallic stent, used by Canfield and Norton in 1933, was made of silver. More recently, nitinol (a nickel-titanium alloy) has been used in virtually all self-expanding metallic stents. The most commonly used nitinol stent is the Ultraflex stent (Boston Scientific; Natick, MA).
Silicone stents (manufactured by Novatech [La Ciotat, France] and Bryan Corporation [Boston, MA]) require performing rigid bronchoscopy for insertion. They are available in straight tracheobronchial varieties, as well as in “Y” configurations. Hybrid stents (eg, Dynamic Stent; Boston Scientific) include metallic support structures and a silicone body. A newer hybrid stent (Polyflex Stent; Boston Scientific), is composed of a woven polyester mesh and a full-length silicone membrane. The Polyflex stent also requires performing rigid bronchoscopy for placement.
Although metallic stents have become popular because of their simple deployment with flexible bronchoscopy, they are generally unsuitable for applications in patients with benign disease. For the most part, only covered, self-expanding metal or silicone stents are appropriate for use in patients with malignant disease.
Rigid bronchoscopy is generally necessary to place stents in patients who have other than routine malignant tracheobronchial disease. Rigid bronchoscopy requires either a state-of-the-art bronchoscopy suite equipped to provide anesthesia or an operating room. However, few interventionalists have enough case volume to request blocks time in an operating room. The resulting uncertainty in procedure scheduling may cause issues with more easily arranged clinic schedules. Dedicating one or two half-days a week for procedures allows more consistent scheduling, but it does not eliminate the issues of operating room availability.