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Professor Emmanuel Martinod * is the designer and director of the first tracheal transplants in the world. He describes here the interest and applications
Paris Match. Which patients is referred for a tracheal transplant?
Pr Emmanuel Martinod. To those who have tracheal involvement itself, (cancer at this level or narrowing). These subjects are in a therapeutic stalemate because how to live without functional trachea? It is also intended for those suffering from cancer affecting one of the two bronchial strains that arise from the trachea, but that must be sacrificed, which amounts to removing a right or left lung (pneumonectomy). This operation is burdened with a heavy mortality (10% at three months), hence the advantage of being able to avoid it by replacing the said bronchial strain.
Has tracheal substitution never been attempted before ?
Tempted for fifty years! First with synthetic prostheses (in Dacron or Teflon) inspired by vascular prostheses. But in contact with the air, which is not sterile, they became infected, which deinserted the sutures with the healthy trachea. Then with tracheae of animal origin or deceased human donors, rendered chemically neutral in the laboratory. This was a new failure, because these allografts are poorly preserved, require immunosuppressors contraindicated in case of cancer and are not recolonized by the bronchial cells of the recipient. Making tracheae in the laboratory from stem cells is only in the planning stage
Why using as a substitute for aortic segments?
The trachea is a set of cartilaginous rings, stacked on each other, endowed with an epithelium and whose vascularization is fine and fragile. The aorta as a substitute has several advantages: it is a duct of similar diameter, elastic, resistant to infection and well tolerated immunologically. Picked from a dead subject, it keeps very well and long cold (cryopreservation). Its disadvantage is that it is much more flexible than a trachea: this is compensated for by sliding inside it, during the operation, a semi-rigid metal frame (stent).
What preliminary steps have you -you had to go before the test in humans?
In ten years, I conducted 7 laboratory studies that showed, on sheep, that aortic segments from the same animal (autograft) or no (allograft), used immediately or after cryopreservation and at different locations (trachea, tracheal bifurcation, bronchial strains), were not accompanied by any rejection, required no immunosuppressive treatment and were recolonized by bronchial tissue. This removed the stent after six months and returned the animals to their normal life on the farm.
What is Surgery?
1. To remove the affected trachea area. 2. To restore an airway with the aortic graft (5-6cm). 3. To insert a stent into it. 4. Wrap the graft with a well-irrigated neck or thorax muscle (vascular supplement). 5. To preserve the diseased lung so as to treat it by removing only the lobe where the cancer sits.
What are the results?
Out of 13 operated, only one died at 90 days of a Stroke of unexplained cause. There was no graft or stent complication. Our decline is seven years for the oldest patient and nine months for the most recent patient. Transformation of the aortic graft into a bronchial cartilaginous duct always occurs, but in a variable manner (5 to 39 months).
See also Trachea transplant: French success after the tragic fiasco of an Italian surgeon
What will be the main applications of the trachea graft?
Those that I have just explained, extended to patients with cancer of the trachea the thyroid invading the trachea, the transplant to save lung function.
* Head of thoracic and vascular surgery department, Avicenne Hospital, Bobigny.
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