Tracheal Stenosis

Tracheal stenosis is narrowing of the tracheal lumen, congenital or acquired, causing fixed upper airway obstruction.

• Causes:
  • Post intubation or post tracheostomy (commonest, 90%; cuff pressure ischaemia, granulation, 6 to 21% of prolonged intubation).
  • Idiopathic subglottic stenosis (middle aged women).
  • Inflammatory: granulomatosis with polyangiitis (subglottic), relapsing polychondritis, sarcoidosis, amyloid, tracheobronchopathia osteochondroplastica, tuberculosis.
  • Malignant: thyroid carcinoma, oesophageal, laryngeal, bronchial carcinoma, lymphoma (extrinsic compression or invasion).
  • Radiation, thermal and chemical (caustic ingestion) injury, trauma, congenital (complete tracheal rings), vascular rings.
• Presents when lumen is reduced to under 8 mm (exertional) or under 5 mm (rest).
• Cotton–Myer grading for subglottic stenosis: grade I (under 50%), II (51 to 70%), III (71 to 99%), IV (no detectable lumen).

• Progressive exertional dyspnoea, stridor (inspiratory or biphasic), wheeze often mistaken for asthma or COPD, cough, difficulty clearing secretions, voice change in subglottic stenosis, recurrent infections.
• Onset typically weeks to months after extubation or tracheostomy decannulation.
• Examination: stridor on forced expiration, tracheal tug, accessory muscle use; flow volume loop plateau.

• Flow volume loop: flattened inspiratory and expiratory limbs (fixed obstruction); FEV1/PEF ratio over 8.
• CT neck and chest with 3D reconstruction and virtual bronchoscopy: site, length, diameter, extent of stenosis, mediastinal structures.
• Flexible bronchoscopy/laryngoscopy: direct visualisation; rigid bronchoscopy under anaesthesia for assessment and treatment.
• Laboratory for inflammatory causes: ANCA, ACE, ESR, CRP; biopsy for suspected sarcoidosis, GPA, amyloid.
• Reflux evaluation in idiopathic subglottic stenosis.

• Acute airway obstruction: heliox (70:30), nebulised adrenaline 1:1000 5 mL, dexamethasone 8 to 10 mg IV, rigid bronchoscopy with dilatation or intubation beyond the stenosis; ECMO as bridge.
• Endoscopic therapy (simple, short, web like or mild stenosis): balloon dilatation, laser radial incisions (CO2, Nd:YAG), mitomycin C 0.4 to 1 mg/mL topical application (reduces restenosis), steroid injection (triamcinolone 40 mg/mL), stenting (silicone Dumon stents; self expanding metal stents avoided in benign disease), recurrence 30 to 60%.
• Definitive surgery for complex, long (over 1 cm), post-intubation circumferential stenosis: tracheal resection with primary end to end anastomosis (success 90 to 95%, up to 50% of tracheal length resectable), cricotracheal resection for subglottic stenosis, laryngotracheal reconstruction with cartilage graft.
• Idiopathic subglottic stenosis: repeated dilatation with steroid injection plus trimethoprim/sulfamethoxazole, or open resection.
• Inflammatory causes: treat disease (GPA: prednisolone 1 mg/kg and rituximab or cyclophosphamide; relapsing polychondritis: steroids, methotrexate), endoscopic dilation.
• Malignant stenosis: debulking (laser, cryotherapy, argon plasma coagulation), stent placement (silicone/metal), radiotherapy, chemotherapy.
• Prevention: limit intubation duration, cuff pressure below 20 to 25 mmHg (25 to 30 cmH2O), early tracheostomy decisions, correct tube size.
• Follow up bronchoscopy, spirometry.