Successful Total Tracheal Replacement by Cryopreserved Aortic Allograft in a Patient Post-COVID-19 Infection

Challenges and Opportunities in Developing Tracheal Substitutes for the Recovery of Long-Segment Defects

Tracheal resection and reconstruction procedures are necessary when stenosis, tracheomalacia, tumors, vascular lesions, or tracheal injury cause a tracheal blockage. Replacement with a tracheal substitute is often recommended when the trauma exceeds 50% of the total length of the trachea in adults and 30% in children. Recently, tissue engineering and other advanced techniques have shown promise in fabricating biocompatible tracheal substitutes with physical, morphological, biomechanical, and biological characteristics similar to native trachea. Different polymers and biometals are explored. Even with limited success with tissue-engineered grafts in clinical settings, complete healing of tracheal defects remains a substantial challenge due to low mechanical strength and durability of the graft materials, inadequate re-epithelialization and vascularization, and restenosis. This review has covered a range of reconstructive and regenerative techniques, design criteria, the use of bioprostheses and synthetic grafts for the recovery of tracheal defects, as well as the traditional and cutting-edge methods of their fabrication, surface modification for increased immuno- or biocompatibility, and associated challenges.

Stented cryopreserved aortic allograft for reconstruction of long-segment post-tuberculosis tracheal stenosis

Tracheobronchial tuberculosis is one of the conditions causing long segment tracheal stenosis and is a clinically challenging scenario. This report describes a successful tracheal reconstruction in a 44-year-old man with long-segment post-tuberculosis tracheobronchial stenosis, utilizing a stented cryopreserved aortic allograft. The procedure was necessitated by the failure of conventional treatments. The stenotic segment was resected and replaced with a cryopreserved aortic allograft, supported by a metallic stent to maintain airway patency. Post-surgery, the patient experienced resolution of dyspnea without major complications. Currently, at 33 months post-operation, the patient enjoys an enhanced quality of life with effective breathing, speaking, swallowing abilities, and has resumed normal daily activities, with regular bronchoscopic follow-ups. This report demonstrates a novel approach for managing challenging tuberculosis-induced long segment airway stenosis.

Endoscopic Management of Benign Airway Stenosis in Coronavirus Disease 2019 Patients

BACKGROUND

 The aims of this study were to evaluate the results of endoscopic dilation for simple benign airway stenosis in coronavirus disease 2019 (COVID-19) patients and whether COVID-19 infection was associated with higher rate of recurrence compared with a control group.

METHODS

 It was an observational multicenter study including consecutive patients with simple benign airway stenosis undergoing endoscopic dilatation with at least 6 months of follow-up. The outcome of patients with COVID-19 infection was compared with that of a control group in relation to patient and stenosis characteristics, and procedure type. Then, univariable and multivariable analyses identified the risk factors for recurrence.

RESULTS

 Seventy-nine patients were included in the study; 56 (71%) of these developed airway stenosis after COVID-19 infection. COVID-19 patients presented a higher rate of stenosis due to prolonged intubation (82 vs. 43%; p = 0.0014); no other differences were found regarding demographic data, characteristics of stenosis, and procedure type. Twenty-four (30%) patients had recurrence after first dilatation (32% for No-COVID-19 vs. 26% for COVID-19 group; p = 0.70), and in 11 (35%) of these, the stenosis recurred after repeated endoscopic treatment (65% for No-COVID-19 vs. 45% for COVID-19 group; p = 0.40). Subglottic stenosis (p = 0.013) and the use of laser (p = 0.016) were significant predictive factors for stenosis recurrence.

CONCLUSION

 COVID-19 infection did not affect the outcome of endoscopic treatment of simple airway stenosis, and the treatment of these subsets of patients should not differ from that of general population.

Tracheal Replacement Techniques and Associated Mortality: A Systematic Review

OBJECTIVE

Tracheal replacement is a crucial operation to enhance the quality of life for patients with extensive tracheal lesions. The most suitable surgical techniques for different clinical conditions remain a topic of debate. Through a reviewing of the relevant literature, this study investigated the association between surgical techniques and mortality rate.

DATA SOURCES

Studies were collected from PubMed, Embase, the Web of Science, the Cochrane Center Register of Controlled Trials, and ClinicalTrials.gov.

METHODS

This systematic review encompassed literature from the inception of each database to May 10, 2023, focusing on tracheal replacement for patients who underwent circumferential resection of the trachea or partial resection with preservation of the posterior membranous wall. Non-human and non-clinical studies were excluded.

RESULTS

About 31 studies were included in the assessment comprising a combination of case reports and case series, and 118 patients underwent tracheal replacement through four underlying methodologies, including tracheal allotransplantation, autologous tissue reconstruction, bioprosthetic reconstruction, or tissue engineering surgery. Each modality exhibits unique advantages and disadvantages, leading to variable outcomes in clinical application.

CONCLUSION

Tracheal replacement is challenging due to the absence of an ideal substitution or graft material. Despite limited clinical successes observed across various modalities, we believe autologous tissue reconstruction for tracheal replacement has the advantage of broadest indications, low rejection rate, and avoidance of immunosuppressive agents. Future research should focus on achieving tracheal replacement that preserves mucociliary clearance, lateral rigidity, and longitudinal flexibility.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1517-1522, 2024.

Management of COVID-19 related tracheal stenosis: The state of art

Tracheal stenosis (TS) is a debilitating disease promoted by pathologic narrowing of the trachea. The acute respiratory distress syndrome caused by COVID-19 has been demonstrated to trigger enhanced inflammatory response and to require prolonged invasive mechanical ventilation as well as high frequency of re-intubation or emergency intubation, thus increasing the rate and complexity of TS. The standard-of-care of COVID-19-related tracheal complications has yet to be established and this is a matter of concern. This review aims at collecting latest evidence on this disease, providing an exhaustive overview on its distinctive features and open issues, and investigating different diagnostic and therapeutic strategies to handle COVID-19-induced TS, focusing on endoscopic versus open surgical approach. The former encompasses bronchoscopic procedures: electrocautery or laser-assisted incisions, ballooning dilation, submucosal steroid injection, endoluminal stenting. The latter consists of tracheal resection with end-to-end anastomosis. As a rule, traditionally, the endoscopic management is restricted to short, low-grade, and simple TS, whereas the open techniques are employed in long, high-grade, and complex TS. However, the critical conditions or extreme comorbidities of several COVID-19 patients, as well as the marked inflammation in tracheal mucosa, have led some authors to apply endoscopic management also in complex TS, recording acceptable results. Although severe COVID-19 seems to be an issue of the past, its long-term complications are still unknown and considering the increased rate and complexity of TS in these patients, we strongly believe that it is worth to focus on it, attempting to find the best management strategy for COVID-19-related TS.

Airway replacement using stented aortic matrices: Long-term follow-up and results of the TRITON-01 study in 35 adult patients

Over the past 25 years, we have demonstrated the feasibility of airway bioengineering using stented aortic matrices experimentally then in a first-in-human trial (n = 13). The present TRITON-01 study analyzed all the patients who had airway replacement at our center to confirm that this innovative approach can be now used as usual care. For each patient, the following data were prospectively collected: postoperative mortality and morbidity, late airway complications, stent removal and status at last follow-up on November 2, 2021. From October 2009 to October 2021, 35 patients had airway replacement for malignant (n = 29) or benign (n = 6) lesions. The 30-day postoperative mortality and morbidity rates were 2.9% (n = 1/35) and 22.9% (n = 8/35) respectively. At a median follow-up of 29.5 months (range 1-133 months), 27 patients were alive. There have been no deaths directly related to the implanted bioprosthesis. Eighteen patients (52.9%) had stent-related granulomas requiring a bronchoscopic treatment. Ten among 35 patients (28.6%) achieved a stent free survival. The actuarial 2- and 5-year survival rates (Kaplan-Meier estimates) were respectively 88% and 75%. The TRITON-01 study confirmed that airway replacement using stented aortic matrices can be proposed as usual care at our center. Clinicaltrials.gov Identifier: NCT04263129.

Treatment of post-resuscitation cicatricial tracheal stenosis after suffering severe COVID-19 associated pneumonia: A report of 11 cases

Objective

Despite the full range of anti-epidemic measures, the rapidly mutating SARS-CoV-2 continues to spread worldwide, causing respiratory and pulmonary pathologies. So far, there are no generally accepted clinical guidelines for treating post-resuscitation cicatricial tracheal stenosis (CTS) after COVID-19 associated pneumonia. This study sought to evaluate the clinical outcomes of surgical treatment and perioperative management of patients who developed CTS.

Methods

A cohort of eleven working-age patients (eight women and three men) with CTS were treated surgically after undergoing invasive artificial ventilation ranging from 5 to 130 days. Along with scarring changes in the tracheal wall, tracheomalacia was noted in five (55.6%) individuals. Circumferential tracheal resection (CTR) with subsequent anastomosis, tracheolaryngeal reconstruction, and endoscopic methods were modalities used to restore airway patency. In cases of CTR combined with tracheoesophageal fistula (TEF), CTR was performed with dissection of the pathological stoma.

Results

In 80% of the cases, CTS was located at the larynx and cervical trachea level. All patients managed to restore adequate breathing through their natural airways with preserved vocal function. No lethal outcomes were observed in the post-op period. Patient outcomes after CTR were considered excellent in nine patients who continued an active lifestyle and went straight to work. One patient, after laryngotracheoplasty and tracheal stenting, is at the final stage of treatment.

Conclusions

These patients are at high risk of developing CTS and require dynamic monitoring. CTR allows early rehabilitation of patients with the best functional outcome. If CTR is contraindicated, laryngotracheoplasty also allows adequate debridement of the tracheobronchial tree and respiratory support.

Mediastinitis after Cryopreserved allograft tracheal transplantation treated by Major omentum transposition

A 56-year-old female presented with an extended adenoid cystic carcinoma of the entire trachea. She underwent a 12-cm fully-circumferential tracheal replacement by a cryopreserved aortic allograft(CAA) stented by a silicon prosthesis to prevent airway collapse. A muscle flap was used to provide neovascularization and prevent fistulization to mediastinal structures. Post-surgery mediastinitis was detected three weeks after surgery and reoperation was performed. A partial allograft necrosis with stent exposure was found. Major omentum transposition allowed neo-trachea coverage, preventing air-leak, providing antibiotics delivery and mediastinal infection treatment. Six months after surgery the patient is alive. Follow-up bronchoscopy showed a satisfactory allograft revascularization.

The Growing Medical Need for Tracheal Replacement: Reconstructive Strategies Should Overcome Their Limits

Breathing, being predominantly an automatic action, is often taken for granted. However, respiratory diseases affect millions of people globally, emerging as one of the major causes of disability and death overall. Among the respiratory dysfunctions, tracheal alterations have always represented a primary challenge for clinicians, biologists, and engineers. Indeed, in the case of wide structural alterations involving more than 50% of the tracheal length in adults or 30% in children, the available medical treatments are ineffective or inapplicable. So far, a plethora of reconstructive approaches have been proposed and clinically applied to face this growing, unmet medical need. Unfortunately, none of them has become a well-established and routinely applied clinical procedure to date. This review summarizes the main clinical reconstructive attempts and classifies them as non-tissue engineering and tissue engineering strategies. The analysis of the achievements and the main difficulties that still hinder this field, together with the evaluation of the forefront preclinical experiences in tracheal repair/replacement, is functional to promote a safer and more effective clinical translation in the near future.