Subglottic stenosis, with involvement of the lower larynx

Laryngotracheal Resection and Reconstruction John D. Mitchell, MD n, Subglottic stenosis is being recognized with increasing frequency in adults, and may be the most frequent indication for airway intervention in this patient population. A variety of factors may lead to subglottic narrowing but in many individuals, usually women, no antecedent cause is identified. Once the diagnosis is recognized, initial management with endoscopic therapy is indicated to provide symptom relief and to gain information about the suitability of open surgical intervention. In most cases, surgical resection and reconstruction will provide the best long term outcome. Operative Techniques in Thoracic and Cardiovasculary Surgery 20:46-62 r 2015 Elsevier Inc. All rights reserved. KEYWORDS subglottic stenosis, trachea, airway resection, cricoid, cricoplasty, larynx Introduction Subglottic stenosis, with involvement of the lower larynx and proximal trachea, is being increasingly recognized in the adult patient population. Indeed, in many busy thoracic practices, it has become the most frequent indication for airway intervention. The usual etiologies post intubation injury, gastroesophageal reflux with aspiration, and following tracheostomy remain present, although an antecedent cause cannot be found in many patients. These cases of idiopathic stenosis are typically seen in women aged 30-60 years, and tend to produce isolated stenosis in the subglottic region. When evaluating these patients, it is important to rule out autoimmune disorders such as Wegener granulomatosis, where the airway disease may progress despite surgical resection. Patients present with the insidious onset of noisy breathing, followed by overt stridor and exercise intolerance. The latter may be at times difficult to elicit from the patient, as individuals often accommodate it subconsciously with lifestyle modifications. Voice changes, difficulty in clearing secretions, and recurrent respiratory infections may also result. Delays in diagnosis often ensue, as the patient is treated with bronchodilators and steroids for adult-onset asthma. The problem becomes apparent with computed tomography imaging of the neck and most importantly, bronchoscopic evaluation, which accurately defines the location, extent, and proximity of the airway stenosis to *Division of Cardiothoracic Surgery, University of Colorado School of Medicine, Aurora, CO Department of Medicine, National Jewish Health, Denver, CO Address reprint requests to John D. Mitchell, MD, Division of Cardiothoracic Surgery, University of Colorado School of Medicine, Academic Office 1, Room 6602, C-310, 12631 E. 17th Ave, Aurora, CO 80045. E-mail: john.mitchell@ucdenver.edu 46 1522-2942/$-see front matter r 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1053/j.optechstcvs.2015.07.003 the vocal cords. These factors are critical when describing therapeutic alternatives to the patient. Treatment options, including endoscopic therapy and surgical resection, should be confined to symptomatic patients. The breadth of endoscopic therapies, including dilation (balloon or rigid bronchoscope) as well as ablative techniques (eg, laser or cryotherapy), is beyond the scope of this article, but they should be attempted initially and occasionally produces long-lasting benefit. However, in most of the patients, the stenosis recurs. Endobronchial stenting of the subglottic larynx is difficult because of issues with stent migration and the proximity to the vocal cords. In some patients who are unfit for surgical resection, a silicone t-tube may be a better choice. However, for most of the individuals, laryngotracheal resection is the best choice to produce a durable, widely patent airway. Conditions optimal for airway resection and reconstruction have been previously described. 1 Patients should be weaned from oral steroids, and active inflammation within the airway should be minimal. It is best to avoid vigorous dilation of the stenosis immediately before resection, as the mucosal disruption from endobronchial therapy may compromise anastomotic healing. During the surgery, development of the pretracheal plane allows for greater mobility of the distal airway segment, minimizing anastomotic tension. Other maneuvers such as suprahyoid release are only rarely needed in cases of extensive resection. A hilar release is not helpful in laryngotracheal resection. Proper patient positioning allows for maximal exposure of the upper airway (Fig. 1). Extubation at the end of the case should be expected, and a protective tracheostomy is rarely, if ever, necessary. Close cooperation between the surgical and the anesthetic teams is critical for the success of the procedure. After fiberoptic inspection of the stenosis through a laryngeal

Laryngotracheal resection and reconstruction 47 mask airway, a small-bore endotracheal tube (ETT) is passed through the cords and beyond the subglottic region. If the stenosis is too severe to permit this, it can be gently dilated to allow passage. The location and length of the stenosis is carefully noted, confirming the extent of resection (Fig. 2). Once the airway is opened within the field, the indwelling ETT is withdrawn and cross-field ventilation is initiated with a new ETT and a sterile circuit is passed to the anesthesiologist; the ETT within the distal trachea may then be removed intermittently to allow suture placement. If a previously placed tracheostomy is present, it is removed justbeforetheskinpreparationandreplacedwithanett with the sterile circuit. Once the anastomotic sutures are placed, the prior indwelling ETT is advanced across the anastomotic site into the distal trachea, and cross-field ventilation is discontinued. If the original ETT retracts into the hypopharynx, the surgeon may assist in directing it back through the glottic opening by passing a sterile ETT exchanger retrograde through the cords to be retrieved by the anesthesiologist. Figure 1 Patient positioning for laryngotracheal resection. A semi-fowler's position is used, with extension of the neck. An inflatable pillow is placed beneath the shoulders to aid in extension; it is deflated when tying the anastomotic sutures to produce mild neck flexion. The skin preparation extends from the chin to the xyphoid.

48 J.D. Mitchell Figure 2 Patterns of stenosis involving the larynx and upper trachea. (A) Stenosis of the upper trachea, without laryngeal involvement. The dashed lines indicate the line of resection, which proximally is just below the cricoid cartilage.

Laryngotracheal resection and reconstruction 49 Figure 2 (Continued) (B) Stenosis of the upper trachea and anterior cricoid. This pattern may be seen in some idiopathic cases and in stenoses due to erosion from a proximally placed tracheostomy tube. The dashed lines indicate the line of resection, with excision of the anterior cricoid arch and some or all of the cricothyroid membrane. The lateral cricoid pillars are beveled to accommodate the advanced distal trachea. The posterior cricoid plate is left intact (See Figs. 3-5).

50 J.D. Mitchell Figure 2 (Continued) (C) Stenosis of the upper trachea and circumferential involvement of the cricoid. This is the most common pattern of idiopathic stenosis. The dashed lines indicate the line of resection. In this case, the excision of airway is similar to (B), with the addition of the scarred mucosa of the posterior cricoid plate. The posterior cricoid plate cartilage is left intact to protect the insertion of the recurrent laryngeal nerves and is resurfaced with a membranous wall flap advanced with the distal tracheal segment (See Figs. 5-10). In cases where there is a limited subglottic vestibule due to narrowing in the lateral dimension, a tailoring cricoplasty is added (Figs. 11-13).

Laryngotracheal resection and reconstruction 51 Figure 3 Laryngotracheal resection with removal of the anterior cricoid arch. Typically, the surgeon divides the airway at or just distal to the stenosis. Cross-field ventilation of the distal airway is initiated, and dissection of the proximal area of involvement is begun. Direct evaluation of the lumen at the cricoid can be further assessed by incising the airway between the cricoid and the first tracheal ring; if the lumen is inadequate, the anterior cricoid arch may be removed. (A and B) Lines of resection. Some or all of the cricothyroid membrane may be excised. It is important to bevel the lateral cricoid arch obliquely to fit the advancing distal airway.

52 J.D. Mitchell Figure 4 Laryngotracheal resection with removal of the anterior cricoid arch. (A and B) The distal trachea is tailored with an anterior prow to fit the defect in the larynx. Lateral traction sutures of 2-0 VICRYL (Ethicon, Inc, Somerville, NJ) are placed in the lateral cricoid pillars proximally and encircling a tracheal ring distally. The anastomotic sutures are then placed, in the manner detailed in Fig. 5.

Laryngotracheal resection and reconstruction 53 Figure 5 Standard anastomotic suture placement for cervical airway surgery. The dashed line depicts the midpoint of the membranous wall; the arrows depict the lateral traction sutures. (A) Individual sutures are placed, beginning with the midpoint of the posterior membranous wall and continuing to the lateral stay suture. A 4-0 VICRYL suture is used for the membranous wall, and a 3-0 VICRYL suture is used for the cartilage. Each suture is placed 2-3 mm deep and 2-3 mm apart, situated such that the knots lie on the outside of the airway. Each suture is tacked to the surgical drapes in a predetermined fashion, allowing for unencumbered tying of the sutures later. (B) After placement of one side of sutures, the second side, or set, of sutures are placed and secured to the drapes. (C) Placement of the anterior sutures. Distally, a tracheal ring is encircled with the anastomotic suture if possible. After placement of all anastomotic sutures, cross-field ventilation is discontinued, and the original ETT is passed through the glottis into the distal tracheal segment. The pillow beneath the upper back is deflated, and slight neck flexion is produced by the anesthesia team. The lateral traction sutures are tied to one another, closely approximating the cut ends of the airway. The anastomotic sutures are then tied, beginning with the anterior cartilaginous portion and finishing with the membranous wall sutures.

54 J.D. Mitchell Figure 6 Laryngotracheal resection for circumferential stenosis at the cricoid level. In addition to resection of the anterior cricoid arch, removal of the scarred mucosa from the posterior cricoid plate (B, line with small dashes) is necessary. (C) To resurface the posterior cricoid, the distal trachea is fashioned not only with a prow but also with a membranous wall flap. This is best done when the laryngeal portion of the resection is completed to facilitate a good fit.

Laryngotracheal resection and reconstruction 55 Figure 7 Laryngotracheal resection for circumferential stenosis at the cricoid level. Lateral traction sutures of 2-0 VICRYL are placed first. Reconstruction is initiated by placing 4 or 5 simple sutures between the base of the membranous wall flap to the caudad edge of the posterior cricoid plate. Deep suture placement in the cricoid is avoided to minimize risk to the recurrent laryngeal nerves, and suture placement in the base of the membranous flap should avoid entry into the lumen (partial thickness). As these sutures avoid the lumen, either permanent or absorbable fine suture material may be used. It may be helpful to use different colored sutures to avoid confusion later with the anastomotic sutures. These sutures are clipped to the surgical drapes, to be tied after the cut ends of the airway are approximated by the tied lateral stay sutures.

56 J.D. Mitchell Figure 8 Laryngotracheal resection for circumferential stenosis at the cricoid level. The advanced cephalad lip of the membranous wall flap is then sewn to the laryngeal mucosa with 5 or 6 simple sutures using 4-0 VICRYL. Although the figure depicts placement after airway approximation, these are usually placed using an open technique and secured to the drapes. These sutures may be placed such that the knots are buried or lie within the lumen; although the buried location is ideal, it may be difficult to achieve, given the delicacy of the laryngeal mucosa. After these sutures are placed, additional simple anastomotic sutures of 4-0 and then 3-0 VICRYL are placed to reach the lateral stay sutures, situated such that now the knots are on the outside of the lumen. At this point, mild neck flexion is produced with deflation of the bag beneath the upper shoulders, and the cut ends of the airway are approximated as the lateral traction sutures are tied. The anastomotic sutures between the base of the membranous wall flap and posterior cricoid are tied first. The sutures securing the cephalad edge of the flap to the laryngeal mucosa are then carefully tied through the aperture created by the resected anterior cricoid arch. The other anastomotic sutures are then tied, reaching to the point of the lateral stays. Occasionally, the surgeon may wish to place 1 or 2 anastomotic sutures anterior to the lateral stays on either side before airway approximation, as placement after tying the lateral stays can be difficult.

Laryngotracheal resection and reconstruction 57 Figure 9 Laryngotracheal resection for circumferential stenosis at the cricoid level. The anterior anastomotic sutures of 3-0 VICRYL are placed last in an open fashion and then tied once all are placed. This brings the prow fashioned from the advancing anterior trachea into the defect in the larynx created by the resection of the anterior cricoid and cricothyroid membrane. When placing sutures in the thyroid cartilage, care must be exercised to avoid impingement on the vocal cords just proximal to the airway opening. During this portion of the reconstruction, an ETT is passed into the distal airway segment through the glottic opening.

58 J.D. Mitchell Figure 10 Laryngotracheal resection for circumferential stenosis at the cricoid level. Cross-sectional view of the completed anastomosis.

Laryngotracheal resection and reconstruction 59 Figure 11 Tailoring cricoplasty. In some individuals, an inadequate lumen remains within the larynx despite removal of the anterior cricoid arch because of narrowing in the lateral dimension. For these situations, one may enlarge the laryngeal orifice at this level by resecting the inner half of the lateral cricoid pillars, depicted by the dashed lines. The overlying laryngeal mucosa must be carefully mobilized to expose the inner half of beveled cricoid on either side, which is then excised either with a knife or fine rongeurs. The latter instrument is particularly helpful if the cricoid pillar is partially calcified. The cricoplasty is accomplished before construction of the anastomosis.

60 J.D. Mitchell Mucosa Figure 12 Tailoring cricoplasty. The inner half of the cricoid pillar has been resected, to be resurfaced by the overlying laryngeal mucosa.

Laryngotracheal resection and reconstruction 61 Figure 13 Tailoring cricoplasty. The laryngeal mucosal flaps may be secured to the remaining cricoid pillars with fine absorbable suture. Alternatively, the author's preference is to simply use the anastomotic sutures to tack the mucosa into place. The cricoplasty may enlarge the subglottic aperture up to 5 mm in the lateral dimension.

62 Summary As noted, extubation at the end of the case is anticipated. Fiberoptic inspection of the anastomosis intraoperatively is hazardous because of the proximity to the vocal cords. However, the surgeon may get some information by deflating the ETT balloon and asking the anesthesiologist to produce low to moderate airway pressures; one wishes to see pneumostasis in the field combined with a sizable leak through the glottis, suggesting a widely patent airway. A small-bore drain and a chin-to-chest stitch to maintain mild neck flexion are routine. Some degree of glottic edema and dysfunction may be anticipated in the early postoperative period, and the patient's diet is advanced only when this subsides and thus aspiration risk is minimal. Before discharge, the anastomosis is inspected by fiberoptic bronchoscopy through a laryngeal mask airway in the operating room under general anesthesia. In general, the reported surgical results are exceptional in properly selected patients, 2-5 with very low morbidity and mortality rates and long-term outcomes judged as good to J.D. Mitchell excellent in 85%-97% of patients. In several studies, dysphonia (alteration in the strength of voice and inability to sing) was the most common adverse event postoperatively. Other complications, such as development of anastomotic granulation tissue, can be managed endoscopically. References 1. Grillo HC: Preoperative considerations. In: Grillo HC, (ed). Hamilton, ON: BC Decker, Inc; 2004. p. 443 451, 2004 2. Ashiku SK, Kuzucu A, Grillo HC, et al: Idiopathic laryngotracheal stenosis: Effective definitive treatment with laryngotracheal resection. J Thorac Cardiovasc Surg 127:99 107, 2004 3. Morcillo A, Wins R, Gomez-Caro A, et al: Single-staged laryngotracheal reconstruction for idiopathic tracheal stenosis. Ann Thorac Surg 95: 433 439, 2013 4. D Andrilli A, Ciccone AM, Venuta F, et al: Long-term results of laryngotracheal resection for benign stenosis. Eur J Cardiothorac Surg 33:440 443, 2008 5. Liberman M, Mathisen DJ: Tailored cricoplasty: An improved modification for reconstruction in subglottic tracheal stenosis. J Thorac Cardiovasc Surg 137:573 579, 2009