INTRODUCTION

Tracheomalacia is a segmental or diffuse weakness of the trachea. If the main stem bronchi are involved the term tracheobronchomalacia is used. At present there is no structured approach for the assessment of paediatric tracheobronchomalacia.

It has always been a difficult problem to address surgically as it indirectly attempts to correct airway collapse. Severe tracheobronchial obstruction can be associated with conotruncal and aortic arch anomalies. One should be aware that tracheomalacia, recurrent tracheoesophageal fistula and severe gastroesophageal reflux all of them can coexist and each alone can present similar symptoms.

A single episode of respiratory arrest due to tracheomalacia is an absolute indication for surgery. For patients who cannot be weaned from mechanical ventilation – early correction will reduce the duration of airway cannulation. Preoperative and postoperative evaluation of patients with severe tracheobronchomalacia can help interlink between manifestations, surgical decision making and postoperative result. (1)

The concept of tracheostomy and long-term mechanical ventilation is no longer the preferred approach due to obvious complication and morbidity associated. Stent placement looks attractive as it is less invasive, however the risk of migration is high. Aortopexy (2) can deal with anterior vascular compression but does not sort out posterior membranous tracheal intrusion. Patients with short or limited portion of malacia may benefit from tracheal resection and end to end anastomosis, however patients with limited segment form a small minority.

To the best of our knowledge, posterior tracheopexy as primary intervention for severe tracheobronchomalacia was done for the first time in Australia. We retrospectively reviewed our single institution experience who underwent posterior tracheopexy for treatment of Severe tracheobronchomalacia.

Case I: Posterior Tracheopexy as Primary Intervention for Severe Tracheomalacia – First time in Australia

A four-month-old child was transferred to Sydney Childrens hospital after respiratory arrest –in context complex medical issues including significant tracheobronchomalacia and recent laryngeal cleft repair, moderate-large ASD with right volume overload, aberrant right subclavian artery, interrupted inferior vena cava with azygous continuation.

Chest X ray revealed over inflation of the right lung with complete collapse of the left lung of long standing. Laryngo broncho oesophagoscopy (LBO) revealed right bronchomalacia with complete collapse and left with at least 50 % collapse. Broad trachealis muscle with intrusion into trachea likely secondary to negative pressure during respiration.

Figure 1a

Preop – Marked hyperinflation of Right lung with mediastinal shift.

Figure 1b

Immediate Postoperative – Improved aeration of left lung

Figure 1c

Patient is extubated. Trachea midline.

CT Chest confirmed the above findings with collapsed left lung and mediastinal shift to the left. The right main bronchus is narrowed from the carina to its branching point. The upper lobe bronchus and bronchus intermedius are relatively large in comparison, likely related to air trapping. The left main bronchus is patent. Only the most proximal portion of the left upper lobe bronchus is visible, more distally, this is collapsed. The aberrant right subclavian artery arising from left aortic arch passing posterior to the trachea and oesophagus.

Figure 2a

Marked hyperinflation of Right lung with complete collapse of the left lung. Interrupted IVC with large azygous vein. Aberrant right subclavian artery passing posterior to trachea and oesophagus

Figure 2b

Marked hyperinflation of Right lung with complete collapse of the left lung. Interrupted IVC with large azygous vein. Aberrant right subclavian artery passing posterior to trachea and oesophagus

The child due to prior respiratory arrest was deemed not safe for extubation and decision for early airway corrective option was planned. A joint clinical meet involving surgeons, cardiologist, ENT, anaesthetist was organized to decide between aortopexy vs posterior tracheopexy, timing for ASD repair, best approach for surgery, intraoperative bronchoscopy, intraoperative anaesthetic challenges, as well as postoperative management plans.

The patient underwent posterior tracheopexy by right posterolateral  thoracotomy (3) approach through 4th interspace, sparing serratus anterior. The right lung was retracted with trepidation to expose the posterior mediastinum with some slight improvement in ventilation and certainly no deterioration.

A very large azygous draining into SVC in usual place was admired and decision made to avoid it. Mediastinal pleura was incised and reflected postero-laterally for later closure. Stay sutures were placed on the SVC and reflected pleura and used for traction. Azygous was slung but not tied. Trachea, right MB and left MB, oesophagus with vagus, thoracic duct and anterior spinal ligament all were dissected and displayed.

The oesophagus was mobilised, very obvious and floppy pars membranacae of trachea and RMB were viewed, with quite reasonable cartilaginous rings felt. Tracheopexy was planned and judged with pulling the PM backwards to the spinal ligament. Aberrant RSC artery was not seen, but felt higher up and was not interfered with.

Figure 3a

Large azygous vein seen in relation with thoracic duct. Trachea, right main bronchus and left main bronchus, oesophagus with thoracic duct and anterior spinal ligament were all dissected and displayed.

Figure 3b

Large azygous vein seen in relation with thoracic duct. Trachea, right main bronchus and left main bronchus, oesophagus with thoracic duct and anterior spinal ligament were all dissected and displayed.

Quite difficult to totally oppose PM and ASL, but was achievable with lung relaxation. Then, 5/0 plegetted Ethibond sutures were placed through the back wall of pars membranacae with intra-luminal excursion with plegets on the PM side. Two in RMB, one in carina and 5 along the trachea to well above floppy bit. These sutures were then passed through the anterior spinal ligament, avoiding thoracic veins draining into azugous, thoracic duct and working around the huge azygous vein. These sutures were tied sequentially with very pleasing apposition. Trachea and RMB then looked very wide and patent with no tendency to collapse.

The patient had a slow and steady recovery postoperatively. On day 7 postop the patient underwent laryngobronchoscopy and extubation. Brochoscopy showed that  the trachealis no longer moved anteriorly with clockwise rotation of the mid and distal trachea. Improvement in the size of the right main bronchus was noted.

The patient was weaned to CPAP and high flows subsequently. Two months postop, as part of secondary intervention, the patient underwent closure of haemodynamically significant ostium secundum ASD and aortopexy for anterior tracheal collapse.

CASE II - Posterior Tracheopexy By Left Thoracotomy Approach

A 3-month-old infant boy had been born with a double aortic arch (5). As a neonate he was quite symptomatic requiring intubation and ventilation with evidence of tracheobronchomalacia. He underwent an early division of the left aortic arch along with the ductus. There was some initial improvement but after around ten days he required reintubation with ongoing evidence of tracheobronchomalacia.

Figure 4

Double aortic arch – right dominant

He then underwent an anterior aortopexy via a superior hemisternotomy. He subsequently remained intubated and ventilated with ongoing evidence of more distal tracheobronchomalacia. It was felt he may well benefit from a posterior tracheopexy rather than proceeding directly to tracheostomy. The risks and benefits of the procedure were discussed with the parents who understood them and accepted them.

A redo postero-lateral thoracotomy via the third intercostal space was performed. The pleural adhesions were taken down with sharp dissection and electro cautery and the left lung was mobilised. The pleura had been closed and was now carefully reopened being careful to stay posterior to the vagus and subsequently the recurrent laryngeal nerve.

The oesophagus was identified at the level of the lung hilum and the tissue anterior to the oesophagus was carefully divided in a superior direction and the oesophagus further mobilised anterior and posterior.

The distal trachea was identified and mobilised down to the carina. A series of sutures were now placed to the pre vertebral fascia and the pars membranous aspect of the trachea from the mid-level to the carina. A total of six interrupted sutures were placed and these were now tied thus pushing the oesophagus toward the right chest. Finally, the pleura was re-approximated with a continuous 6/0 Prolene suture. There had been some chyle like fluid during the dissection but after the tracheopexy there was no obvious fluid seen.

The patient was extubated six days postoperatively. He was put initially on CPAP followed by high flows and subsequently to room air.

DISCUSSION

Tracheomalacia/ Tracheobronchomalacia manifest with increased airway compliance and failure to maintain adequate open tracheal lumen throughout the respiratory cycle. Many children do not need any surgical correction as symptoms are mild to moderate and may resolve by two years of age.

There are no standard criteria for diagnosing tracheomalacia endoscopically, however the consensus is more than 50 % narrowing of the lumen with forced exhalation. A large chunk of infants with tracheomalacia have in excess of 75% luminal collapse, with complete tracheal collapse in more than 30 %.

For the patients with severe symptoms needing surgical intervention, laryngo broncho oesophagoscopy (LBO) and MDCT scan showing position of vessels and other important structures in the mediastinum are very important and help in the subsequent surgical approach.

Tracheostomy and long-term mechanical ventilation are no longer the preferred choice. Stents look attractive in short term but have high failure and migration rate. Aortopexy can benefit where anterior vascular compression / anterior tracheal collapse is the etiology but does not solve the problem of posterior membranous tracheal intrusion.

Effective surgical strategy to relieve tracheomalacia is case specific. Segment of trachea/bronchus involved, cartilage formation, vascular anomaly, side of aortic arch, arch anomalies , coexisting trachea-esophageal fistula, severe gastro-esophageal reflux, abnormal airway, lung status/ anomaly, cardiac defects should all be part of the surgical assessment.

Short segment tracheomalacia is ideal for tracheal resection end to end anastomosis or a slide tracheoplasty when it includes less than 30 % of tracheal length. This group forms a very small subset of patients with tracheomalacia.

Right posterior thoracotomy (in children with left aortic arch) with posterior trachea bronchopexy with intraoperative bronchoscopy helps to relieve posterior compression of trachea and both mainstem bronchi in one single intervention. The left sided approach suits patients with right aortic arch.

For patients who have secondary tracheobronchomalacia due to vascular anomalies (6) and innominate artery compression or have coexisting cardiac condition requiring intervention, an anterior approach via median sternotomy deems ideal. Posterior tracheopexy as primary intervention for severe tracheomalacia was done for the first time in Australia. Our stepwise approach allowed a good favourable outcome in patients with complex airway and cardiac disease.

On postoperative follow up bronchoscopic evaluation we observed that posterior tracheopexy was quite effective in addressing posterior intrusion type tracheomalacia with promising short-term result with improvement or resolution of clinical symptoms.

With the vast complexity involved with tracheomalacia, a standardized approach to evaluation, a multi-disciplinary team to decide case specific surgical plan, postoperative airway management, and long term follow up strategy should be in place.