Matthew P. Fox and Douglas J. Mathisen
INDICATIONS/CONTRAINDICATIONS
Subglottic laryngotracheal stenosis is caused by a variety of processes including: Intubation, cricothyroidotomy, trauma, burns, and Wegener granulomatosis. However, idiopathic laryngotracheal stenosis (ILTS) has been the most common indication for laryngotracheal resection and reconstruction in case series over the past 25 years. In general, with the exception of Wegener granulomatosis, all of the above conditions may be cured with a single-stage resection and reconstruction of the airway, as long the stenosis does not extend all the way to the vocal cords. In addition, tumors, most commonly invasive thyroid carcinomas, may extend across the laryngotracheal junction and require partial resection of the cricoid to obtain negative margins.
PREOPERATIVE PLANNING
A careful history and physical examination should be performed on every patient. ILTS is a diagnosis of exclusion. Other causes of tracheal stenosis are usually readily identifiable from history. However, an anticytoplasmic nuclear antigen (ANCA) panel should be drawn on every patient to rule out collagen vascular diseases such as Wegener granulomatosis. These may not respond to resection and reconstruction and should be managed with serial dilation, local steroid injection, or systemic therapy.
Imaging should be obtained to help determine the anatomy and extent of the stenosis. Either conventional tracheal radiographs with PA, oblique, and lateral views of the neck or a thin slice spiral CT of the neck may suffice. MRI may also be obtained in select circumstances but does not ordinarily provide information different than CT.
For patients with alterations of their voice or a traumatic etiology suggesting vocal cord dysfunction or glottic inadequacy, otolaryngology consultation should be obtained prior to any elective procedures on the more distal airway. It is advantageous for these problems to be corrected first to allow for safe extubation at the end of any subglottic resection and reconstruction. Patients should be weaned off systemic steroids prior to any planned resection, as their use is associated with an increased risk of anastomotic complication. Those with symptomatic gastroesophageal reflux should have this addressed medically, or surgically if necessary, to protect the anastomosis in the postoperative period.
Figure 36.1 Rigid bronchoscopic view of a patient with subglottic stenosis
Finally, the patient should undergo endoscopic examination of the airway. This may be done using either flexible or rigid bronchoscopes though a rigid bronchoscope should be readily available in the event that dilation of the stricture is needed to obtain an adequate airway. Care should be taken to assess the length and degree of stenosis, as well as its relationship to the vocal cords (Fig. 36.1). General anesthesia with a laryngeal mask airway may optimize visualization of the proximal airway and vocal cords. If the stenosis abuts the vocal cords or vocal cord mobility is impaired, it is not possible to perform a single-stage correction (Fig. 36.2). The patient’s airway should be temporized with dilation, and they should be referred to an otolaryngologist.
Tracheostomy should be avoided, if possible, as its presence dictates a longer tracheal resection at the definitive operation. It is preferable to temporize the airway with dilation instead. The authors’ preference is to use Jackson dilators and graduated rigid bronchoscopes. Balloon dilation is an acceptable alternative but may prove difficult with more proximal lesions. Lasers and cryotherapy should be avoided as it is difficult to control the depth of injury and subsequent scarring and granulation may complicate final reconstruction.
If active inflammation is present, resection and reconstruction should be delayed until it subsides. Twice a day saline nebulizers and short courses of antibiotics may be useful for controlling localized tracheitis, preoperatively. If dilation is performed during evaluation, a short course of steroids (dexamethasone 10 mg IV during the procedure, followed by 4 mg IV every 6 hours for 24 hours) is often prudent to prevent edema.
Figure 36.2 Diagrams of the typical distribution of idiopathic laryngotracheal stenosis. A: Lesion confined principally to the upper trachea, but which usually impinges on the low subglottic larynx at cricoid level. B: Lesion commencing in the subglottic larynx with narrowing of the immediate subglottic space, which however, leaves an “atrium” beneath the cords. The maximum stenosis is at cricotracheal level. C: More marked stenosis immediately below the vocal cords with little space for anastomosis even at that level.
SURGERY
Anesthesia
An anesthesia team experienced in airway surgery is critical to a safe and efficient operation. In general, the patient is induced with a short-acting intravenous agent with the surgical team and rigid bronchoscopy immediately available as positive pressure ventilation may convert a partial to a complete obstruction. Jackson dilators and rigid bronchoscopy are then used to dilate the stenosis until it is large enough to accept a 5 or 5.5 endotracheal tube. The patient is then intubated. Anesthesia may be maintained using inhalation agents, however, total intravenous anesthesia with short-acting agents such as propofol and remifentanil allow for continuous anesthesia when inhalation is interrupted by the surgical team and early extubation at the conclusion of the case.
Positioning
After intubation, the patient is maintained in a supine position with the head of the bed gently elevated. A thyroid bag placed beneath the patient’s shoulder is inflated to extend the neck 20 degrees. The arms are left at the patient’s sides. The patient’s neck and chest are prepped and draped. Cross-field ventilation equipment is prepared for use.
Technique
A low collar incision one fingerbreadth below the cricoid is performed and carried through the platysma. Subplastysmal flaps are then elevated to the superior margin of the larynx, inferiorly to the sternal notch, and laterally to the sternocleidomastoid muscles. Gelpi retractors are placed to spread the skin. The strap muscles are then split in the midline and the thyroid isthmus divided and suture ligated. The thyroid sutures are left in place for traction. A Weitlaner retractor is used to retract the strap muscles laterally. The pretracheal plane is then entered and developed to the carina using blunt dissection similar to mediastinoscopy.
Circumferential dissection of the trachea is then commenced at the lower aspect of the lesion. This should be done sharply and directly on the trachea to avoid injury to the recurrent laryngeal nerves. No effort is made to dissect the nerves out. The trachea is then divided at the distal aspect of the stricture. It should be circumferentially mobilized no more than 1 to 2 cm from the cut edge to prevent devascularization. Resection should be conservative until the full extent of cricoid and tracheal involvement is assessed. In addition, trachea may be excised serially until the distal margin is free of disease. 2-0 vicryl traction sutures are placed on either lateral aspect of the distal trachea at least two rings from the cut edge to allow for stretching of the trachea upon reconstruction. The endotracheal tube may be then withdrawn and cross-field ventilation initiated when convenient.
The proximal stenotic segment is then grasped with Allis clamps and the trachea is sharply dissected superiorly to the inferior margin of the cricoid laterally and posteriorly. The posterior dissection should not be carried above the lower border of the posterior cricoid plate as this may endanger the recurrent laryngeal nerves. Anteriorly, the cricothyroid muscles are dissected off their attachments to the anterior and lateral cricoid cartilage. The line of resection begins anteriorly in the midline below the thyroid cartilage and bevels inferiorly and posteriorly 45 degrees through the cricoid membrane and the lateral laminae of the cricoid cartilage (Fig. 36.3A and B).
The posterior and lateral aspects of the proximal airway are then assessed. For patients with a circumferential stenosis, which is typical of ILTS, a shelf-like scar will remain on the posterior cricoid plate. This should be excised by making a transverse incision in mucosa of the posterior cricoid plate inferior to the vocal cords (Fig. 36.4). The thickened submucosa and scar are then sharply dissected off the anterior surface of the posterior cricoid plate leaving the cartilage intact to preserve the recurrent laryngeal nerves. If narrowing exists on the lateral aspect of the airway, tailored cricoplasty may be performed. Three to four millimeters of submucosa is excised, sharply, while preserving the overlying mucosa as a pedicle flap. The inner 1 mm of cricoid cartilage may be excised if it is thickened (Fig. 36.5). The mucosa is then sutured to the remaining cricoid cartilage with a series of interrupted 5-0 chromic sutures to resurface the cartilage and decrease granulation. 2-0 vicryl stay sutures are then placed in the lateral cricoid lamina; these should not enter the larynx.
Figure 36.3 A,B: The anterior half of the cricoid is resected beginning in the midline with the line of resection sweeping posteriorly and inferiorly through the lateral cricoid laminae. The edge is beveled to 45 degrees. An anterior prow in the distal trachea is tailored to fit into this defect. C,D: 2-0 vicryl stay sutures are placed in the lateral cricoid lamina and in the lateral aspect of the trachea at least two rings below the cut edge.
The distal trachea is then prepared for anastomosis by creating an anterior prow to fit into the laryngeal defect. The prow should only encompass one tracheal ring to preserve the structural integrity of the airway. If the posterior cricoid plate requires resurfacing, a full-thickness flap of membranous wall is tailored with slightly curved edges to cover the exposed cartilage (Fig. 36.4).
If no posterior resurfacing is required, the anastomosis is then commenced using interrupted 4-0 vicryl sutures 3 to 4 mm apart and 3 to 4 mm from the cut edge of the trachea with the knot outside the airway. The posterior sutures are placed first. On the tracheal side full-thickness bites through the mucosa should be obtained. On the proximal side, partial-thickness bites of laryngeal cartilage may be obtained as long as the purchase is secure and mucosa is obtained with each suture. All sutures are placed before tying and are secured to the drapes with hemostats in an organized manner. The oral endotracheal tube is then advanced. This may be facilitated by passing a red rubber catheter retrograde through the larynx and suturing it to the endotracheal tube. Next, the thyroid bag is deflated, neck flexed, and the 2-0 vicryl stay sutures on either side are tied together. The anterior sutures are then tied next, working laterally to medially on each side. The posterior sutures are tied last, again working laterally to medially (Fig. 36.6).
Figure 36.4 A,B: If posterior scarring and thickening of the submucosa is present, a partial-thickness transverse incision is made in the posterior larynx inferior to the vocal cords. The mucosa and submucosa are then sharply dissected off the posterior cricoid plate leaving the cartilage in situ. A posterior membranous wall flap is then tailored on the distal trachea for resurfacing of the posterior cricoid plate. C: Completed resurfacing of the posterior larynx.
Figure 36.5 If lateral narrowing of the airway is present, tailored cricoplasty is performed by sharply creating a pedicled mucosal flap that is preserved. The inner 1 mm of cricoid cartilage may also be sharply removed if it is thickened (A). The thickened submucosa is sharply removed (B). The mucosal flap is then secured to the cartilage with interrupted 5-0 vicryl sutures to resurface the lateral larynx (C).
If posterior resurfacing is performed, four 4-0 vicryl interrupted sutures are placed between the inferior aspect of posterior cricoid cartilage and the inferior aspect of the membranous wall flap. These sutures should not penetrate the membranous wall mucosa and are not tied (Fig. 36.7). Next the laryngeal mucosa is sutured to the membranous wall flap edge with interrupted 4-0 vicryl sutures. Again, the knots should lie outside the airway and are left untied (Fig. 36.8). Next, the standard anastomotic sutures are placed, posteriorly to anteriorly, taking bites of the laryngeal mucosa and the lateral cricoid laminae on the proximal side and full-thickness bites of the tracheal mucosa and cartilage on the distal side. These are continued anteriorly until two sutures have been placed anteriorly to the 2-0 traction sutures.
The thyroid bag is deflated, and the patient’s neck placed in flexion. The 2-0 traction sutures are tied first, followed by the first four vicryl sutures placed between the posterior membranous flap and the inferior edge of the posterior cricoid plate. The cross-field endotracheal tube will need to be removed intermittently to tie these sutures. Next, the internal sutures between the laryngeal mucosa and edge of the membranous wall flap are tied. The remaining sutures are tied posteriorly to anteriorly until the lateral traction sutures are reached. Finally, the remaining sutures are placed laterally to anteriorly (Fig. 36.9). The oral endotracheal tube is advanced distally, and the remaining sutures tied.
The patient is then ventilated with the balloon down to check for an air leak around the tube and for any air leak form the anastomosis. If a leak from the anastomosis is found, this should be repaired with simple interrupted sutures. The thyroid isthmus and/or strap muscles are then approximated and sutured to the larynx and trachea above and below the anastomosis as a buttress using interrupted silk sutures (Fig. 36.10). This also provides separation from the skin in the event of a wound infection. A 15-French flat Jackson-Pratt drain is left in the subplatysmal space, and the platysma and skin are closed with running vicryl sutures. A no. 2 Ethibond guard stitch is then placed between the patient’s submental crease and presternal skin to prevent neck hyperextension in the immediate postop period. Extreme neck flexion should be avoided as this may lead to paralysis. If there is an air leak around the endotracheal tube with the cuff down, the patient is extubated at the end of the procedure.
Figure 36.6 Completed laryngotracheal anastomosis.
Figure 36.7 If posterior resurfacing is required, it is initiated by placing four interrupted 4-0 vicryl interrupted sutures between the inferior edge of the posterior cricoid and tracheal membranous wall flap. The sutures should not involve mucosa of the trachea and the knots should lie outside the airway.
Figure 36.8 A series of interrupted 4-0 vicryl sutures are placed between the laryngeal mucosa and the edge of the trachea taking full-thickness bites of the membranous wall flap.
Figure 36.9 After the 2-0 stay sutures, internal sutures, and standard anastomotic posterior sutures have been placed and tied, the anterior sutures between the laryngeal cartilage and anterior trachea are placed.
Figure 36.10 The completed anastomosis is buttressed with thyroid isthmus and/or strap muscles sutured together to the larynx and trachea above and below the anastomosis. Strap muscle may also be sutured to the trachea inferiorly to exclude the innominate artery.
If no air leak is present around the endotracheal tube and this is thought to be due to edema, the patient should remain intubated for 48 hours, diuresied and treated with dexamethasone. After 48 hours, they are returned to the operating room. If a leak around the tube is present, the patient is extubated; otherwise tracheostomy is performed two rings below the anastomosis. The smallest practical tracheostomy should be used. If an inadequate airway is anticipated at the conclusion of the initial repair, tracheostomy should be performed immediately.
POSTOPERATIVE MANAGEMENT
The patient is observed overnight in the ICU. Strict npo, voice rest, and upright positioning are maintained. Narcotic pain medication is avoided. The drain is generally removed on postoperative day 3 or 4. The anastomosis is evaluated bronchoscopically on postoperative day 6 or 7. If satisfactory, the chin stitch is cut and a diet is started. If this is tolerated, the patient is discharged the following day. Instructions should be given to avoid neck extension or rotation for 3 to 4 weeks.
COMPLICATIONS
The patient’s airway and incision should be closely monitored postoperatively. Wound infections are rare, and their presence should be cause to assess the anastomosis with CT or bronchoscopy. Hemoptysis, new expiratory or inspiratory stridor, subcutaneous air, or respiratory difficulties should prompt evaluation as well.
Edema may develop at the anastomosis 24 to 120 hours postoperatively and is often associated with mild inspiratory stridor. This may be treated with 24 hours of dexamethasone and diuresis. In severe circumstances, the patient should be moved to the ICU for observation and started on heliox. If intubation is necessary, this is preferably done in the operating room with fiberoptic bronchoscopy and a small endotracheal tube (ET) tube. The patient should then be kept intubated for 48 hours to allow the swelling to resolve. If it does not, tracheostomy two rings below the anastomosis should be performed.
If a large dehiscence of the airway is detected, the patient should be taken back to the operating room for exploration and stabilization of the airway. Repair of the anastomosis may be attempted, but if the integrity of the airway is in doubt, tracheostomy should be performed. If a small amount of flap necrosis is present, hyperbaric oxygen may assist in maintaining the viability of the remaining flap. Granulation tissue may occur at the anastomosis at sites of small dehiscence. This may be debrided bronchoscopically. Finally, recurrent stenosis may occur. This can be managed with dilation as necessary. Redo resection and reconstruction may be attempted in selected circumstances if an adequate proximal margin and tracheal length remain.
RESULTS
Short- and long-term results from laryngotracheal resection are usually excellent. In the 2002 MGH series, Ashuku et al. reported on 73 patients with ILTS treated over 31 years with no deaths. Ninety-two percent of patients were extubated in the operating room and needed no further airway interventions. Nine percent of patients had tracheotomies placed due to laryngeal edema. The majority of these patients were early in the series, and all were decannulated by 3 months. Wound infections and swallowing problems were rare. Long-term results based on the patients’ voice and breathing were classified as excellent (normal voice and respiration), good (mild voice weakness and dyspnea with exertion), fair (hoarseness and exercise limitations), poor (very weak voice and dyspnea with normal activity), and failure (permanent T-tube or tracheostomy). At a median follow-up of 8 months, 26% of patients were classified as excellent, 64% as good, and 7% as fair. Only one patient has a poor result, and there were no failures.
Liberman et al. published a series of 18 patients undergoing laryngotracheal resection and reconstruction with tailored cricoplasty. Results were also excellent. One patient required reintubation on postoperative day 2 for laryngeal edema. An additional patient required intubation for an anaphylactic reaction to soap postoperatively. Both of these patients were extubated. No patient required long-term tracheostomy, and on a scale of 1 to 10, patient satisfaction was rated at 9.5 on medium-term follow-up.
CONCLUSIONS
Laryngotracheal resection and reconstruction is a safe technique for the treatment of subglottic stenosis in the hands of an experienced surgeon with excellent short- and long-term results.
Patients with ANCA positivity are usually excluded due to its association with Wegener granulomatosis. These patents may be treated with serial dilations, steroid injection, and systemic therapy.
Patients should be evaluated by flexible and rigid bronchoscopy prior to reconstruction. An adequate laryngeal ventricle below the vocal cords is required for single-stage reconstruction.
Posterior resurfacing and tailored cricoplasty allow the surgeon to effectively deal with posterior and lateral narrowing of the subglottic space when found.
Recommended References and Readings
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