We read with interest the article “Tracheal Allotransplantation–Lessons Learned” by
Iyer et al.[1] Authors should be commended for a formidable undertaking of successful vascularized,
decellularized tracheal allotransplantation for malignancy for the first time. Though
the end result was not favorable, they have very meticulously analyzed the causes
leading to failure, such as the size of the tracheal allograft and most importantly
the anastomosis, which has been considered the Achilles’ heel causing major complications,
rejection, and even mortality.
Vascularized allografts are currently the most preferred way and provide structural
and mechanical support but require a donor, short-term immunosuppression, and several
weeks for heterotopic revascularization.[2] Aortic auto/homograft or tubularized autologous vascularized tissue supported either
by a stent or costal cartilage has the advantage of single-stage procedure without
immunosuppression. However, it is technically difficult due to donor-site morbidity
and lacks mucociliary clearance.[3]
[4] Tissue-engineered biodegradable scaffold or decellularized trachea seeded with autologous
stem cells has the possibility of growth potential and can be used without immunosuppression,
but it is avascular. Avascular graft exposed to exterior toxins, microorganisms, desiccation,
and continuous movements during respiration/swallowing/coughing leads to infection
and anastomosis failure and may cause disastrous complications such as arterial erosion,
dehiscence, stenosis, or migration.[5] It is surprising that in spite of many failure of prosthetic trachea or tissue-engineered
tracheal allograft, reports of its use are still afloat.
Creation of a tracheal substitute is a life-saving procedure to restore severely damaged
airway in critically ill patients. Theoretically, precise technique, minimizing anastomotic
tension, preserve blood supply, release maneuvers covering the anastomosis and/or
innominate artery with a strap muscle, and low threshold for tracheostomy (in cases
of doubt) will reduce the chances of anastomotic failure. However, tracheal transplantation
has had very limited success owing to issues of ischemia and immune rejection.
Ideal tracheal substitute still eludes us, and its successful clinical use remains
the ultimate challenge. The authors have used the most promising solution for a reliable
tracheal substitute, but questions like when, how, and which patient remain. But one
thing is sure that plastic surgeons have a unique opportunity to significantly contribute
to the science and technique of tracheal reconstruction due to abundant experience
of microsurgery and tissue transplantation.
