Functional identification of abductor and adductor branches for laryngeal transplantation.

PURPOSE: This is a feasibility study of functional identification of the abductor and adductor recurrent laryngeal nerve branches, which could be used in the donor's larynx for functional laryngeal transplantation. METHODS: The study was performed on swine (n = 3) and human (n = 4) models of a donor larynx. The recurrent laryngeal nerve and its branches were found. Using stimulator, abductor and adductor branches were identified, and glottis closing and opening were captured with an endoscope. RESULTS: The result was positive if two ENT specialists noticed at least one adduction and one abduction movement in the same subject. It was obtained in three out of three swine and three out of four humans. CONCLUSIONS: This study shows a way of reinnervation of a transplanted larynx which might result in a functional organ. It describes the first step of the procedure: functional identification of the abductor and adductor branches of the recurrent laryngeal nerve in the donor before the larynx is excised for transplantation.

First Complex Allotransplantation of Neck Organs: Larynx, Trachea, Pharynx, Esophagus, Thyroid, Parathyroid Glands, and Anterior Cervical Wall: A Case Report.

OBJECTIVE: Evaluate the possibility of performing a complex vascular allotransplant of all neck organs including skin. SUMMARY BACKGROUND DATA: There are 2 previous attempts described in the literature, none of them being that complex. The first one is nonfunctional due to chronic rejection, the second one is viable yet considerably limited in complexity (no parathyroids, no skin). METHODS: The allotransplantation was performed simultaneously on 2 adjacent operating rooms, using microsurgical techniques. RESULTS: The patient's voice, breathing through mouth, swallowing, and endocrinal functions have been fully restored. CONCLUSIONS: Achieved results show clearly that such operations performed in selected patients can nearly fully restore functional and aesthetic effects in 1 single procedure.

Prefabrication and prelamination strategies for the reconstruction of complex defects of trachea and larynx.

Complex tracheal and laryngeal defects can be reconstructed using prelamination and prefabrication techniques. Three clinical situations are described in detail in the article. In short segment restenosis defects within scarred surroundings, we restore the fibrocartilaginous defect with a radial forearm fascia flap prelaminated with buccal mucosa or cartilage. This provides a newly vascularized inner lining to the tracheal defect and restores the tubular convexity. For long segment defects we need a technique that can withstand respiratory forces. We use a heterotopic prefabrication strategy to vascularize a tracheal allograft wrapped in forearm fascia. Chimerism is created by replacing donor respiratory epithelium with buccal mucosa of the recipient. After orthotopic transfer, this chimerism allows immunosuppression to be tapered and stopped when bronchoscopy shows mucosal integrity of the new trachea, since the recipient epithelium replaces the allogeneic inner tracheal lining by means of a chronic rejection process. A distinct situation occurs after resection of a unilateral larynx tumor, which usually results in a total laryngectomy with loss of both vocal cords, since reconstruction of the hemilarynx is considered too complex. First, we prefabricate a nearby four-ring autologous tracheal segment using radial forearm fascia. In a second stage, this orthotopically vascularized trachea restores the laryngeal structure with the aim to conserve one vocal cord and thus speech. Orthotopic and heterotopic prelamination and prefabrication strategies offer efficient and reproducible solutions for the restoration of challenging short and long segment tracheal defects, as well as unilateral laryngeal defects. The series in this review article are based on previous studies and case reports. The level of evidence is III-"Study of nonconsecutive patients, without a universally applied gold standard: case-control study".

Immunosuppressive protocols after laryngeal transplantation: a systematic review.

BACKGROUNDS: Larynx transplantation has been successfully performed four times, in 1998, 2010, 2015 and 2023 remained the ultimate goal of voice, feeding and breathing rehabilitation. OBJECTIVE: Immunosuppressive protocols used during the previous successful larynx allotransplantation are detailed. MATERIAL AND METHODS: A systematic review of the literature on PUBMED/Medline, Cochrane and Embase was conducted. Articles relating to actual human larynx transplantations were included. RESULTS: Bibliography search gathered N = 10 publications related to the performance and follow-up of human laryngeal transplantations. N = 8 publications were included corresponding to N = 3 actual human larynx transplantations performed in 1998 and 2010 in the USA and in 2015 in Poland. Immunosuppression protocols, induction and maintenance strategies, rejection monitoring and history of all the three previous laryngeal grafts were detailed. CONCLUSIONS: Beyond the surgical prowess, larynx transplantation is feasible and associated with a reasonably successful outcome when compared to other solid organ transplants. Immunosuppressive regimen protocols and technologies for the monitoring of the organ viability have evolved. SIGNIFICANCE: The reevaluation of this surgical option serves as the reminder of the critical necessity to implement a meticulous immunosuppression protocol when transplanting this inherently immunogenic composite organ, the larynx.

Laryngeal transplantation in minipigs: early immunological outcomes.

Despite recent tissue-engineering advances, there is no effective way of replacing all the functions of the larynx in those requiring laryngectomy. A recent clinical transplant was a success. Using quantitative immunofluorescence targeted at immunologically relevant molecules, we have studied the early (48 h and 1 week) immunological responses within larynxes transplantated between seven pairs of National Institutes of Health (NIH) minipigs fully homozygous at the major histocompatibility complex (MHC) locus. There were only small changes in expression of some molecules (relative to interindividual variation) and these were clearest in samples from the subglottic region, where the areas of co-expression of CD25(+) CD45RC(-) CD8(-) and of CD163(+) CD172(+) MHC-II(-) increased at 1 week after transplant. In one case, infiltration by recipient T cells was analysed by T cell receptor (TCR) Vß spectratype analysis; this suggested that changes in the T cell repertoire occur in the donor subglottis mucosal tissues from day 0 to day 7, but that the donor and recipient mucosal Vß repertoires remain distinct. The observed lack of strong immunological responses to the trauma of surgery and ischaemia provides encouraging evidence to support clinical trials of laryngeal transplantation, and a basis on which to interpret future studies involving mismatches.

Ten-month laryngeal allograft survival with use of pulsed everolimus and anti-alphabeta T-cell receptor antibody immunosuppression.

OBJECTIVES: The risks of daily immunosuppression limit the use of laryngeal transplantation as a reconstructive option. Pulsed immunosuppressive dosing can lessen these risks. The study objective was to develop a long-term pulsing regimen that minimizes exposure to immunosuppressive agents. METHODS: Rat laryngeal transplantation was performed. Everolimus (1 mg/kg per day) and anti-c41 T-cell receptor (TCR) antibodies (250 microg) were given for 7 days beginning 1 day before transplantation and for 5 days beginning on day 90 after transplantation. On day 180, group 1 (n = 5) received the initial regimen for 3 days, and group 2 (n = 5) received everolimus (1 mg/kg per day) until euthanization, which occurred when parathyroid hormone (PTH) levels dropped to less than 11 pg/mL or at 300 days. RESULTS: Four of the 5 rats in group 1 had normal PTH levels at 300 days. The PTH level for 1 rat was less than 11 pg/ mL at 270 days. In group 2, none of the 5 rats had normal PTH levels at 300 days. Two had PTH levels below 11 pg/mL at 270 days, and 3 had PTH levels below 11 pg/mL at 300 days. The allografts that survived beyond 300 days had an essentially normal histologic appearance. CONCLUSIONS: Pulsed immunosuppression prevented allograft rejection for 10 months and was more effective than daily everolimus. Short-term perioperative therapy followed by pulsed, tapered dosing is a viable alternative to traditional regimens and may decrease associated risks.

Laryngeal transplantation in minipigs: vascular, myologic and functional outcomes.

There is no effective way of replacing all the functions of the larynx in those requiring laryngectomy. Regenerative medicine offers promise, but cannot presently deliver implants with functioning neuromuscular units. A single well-documented laryngeal transplant in man was a qualified success, but more information is required before clinical trials may be proposed. We studied the early response of the larynx to laryngeal transplantation between 17 pairs of NIH minipigs full matched at the MHC2 locus. Following iterative technical improvements, pigs had good swallowing and a patent airway at 1 week. No significant changes in mucosal blood flux were observed compared with pre-operative measurements. Changes in muscle morphology and fibre phenotype were observed in transplant muscles retrieved after 7 days: the levels of fast and slow myosin heavy chain (MyHC) protein were reduced and embryonic MyHC was up regulated consistent with denervation induced atrophy. At 1 week laryngeal transplantation can result in good swallowing, and is not associated with clinical evidence of ischemia-reperfusion injury in MHC-matched pigs.

[Inhalation anesthesia during spontaneous ventilation in a patient with a tracheolaryngeal transplant requiring debridement of fibrous tissue obstructing the lumen]. / Anestesia inhalatoria con preservación de la ventilación espontánea en un paciente trasplantado de laringe y tráquea sometido a desbridamiento intraluminal.

Graft stenosis from fibrous granulation tissue is not an uncommon problem in recipients of a transplanted trachea and larynx. We describe the case of a man with a transplanted trachea who was seen for respiratory difficulty and stridor secondary to stenosis. Examination through a rigid bronchoscope and surgical debridement were both performed under anesthesia with sevoflurane alone while the man breathed spontaneously. The outcome of treatment with sequential debridements of fibrotic tissue and autologous stem cell injection was satisfactory and the patient was discharged.

Laryngeal Transplantation.

Laryngeal transplantation offers the hope of replacing voice and laryngeal function in patients with debilitating laryngeal injuries or loss of the larynx from trauma or oncologic reasons. Our group at UC Davis performed a laryngotracheal transplantation, and our experience is reviewed in this chapter. The indications, challenges, and limitations of this procedure are highlighted, and the world's other published cases are reviewed.

New mouse model for studying laryngeal transplantation.

OBJECTIVES: Laryngeal transplantation research has been studied in various animal models. For in-depth, immunology-based transplantation research, however, a thoroughly studied animal model must exist. The purpose of this study was to develop a reliable surgical technique in mice to serve as a model for further study of laryngeal transplantation. METHODS: Heterotopic laryngeal transplantation was attempted in 15 immunocompetent mice by use of modifications of previously described techniques established in rats. RESULTS: Various microvascular techniques were used that led to 8 successful transplants (of 15) with patent vascularity at the time of sacrifice. The first 7 attempts at transplantation were unsuccessful because of technical difficulties related to vessel size, soft tissue traumatic injury, and venous congestion. Subsequently, 8 transplantation procedures were successfully performed after modifications of the surgical technique. CONCLUSIONS: This pilot study describes the reproducible surgical techniques performed in using mice for studying laryngeal transplantation. Mice are cost-effective and immunologically well studied, and are thus ideal for further laryngeal transplantation research.

Development of perioperative care for pigs undergoing laryngeal transplantation: a case series.

Pigs are ideal animal models for airway surgical research, facilitating the successful translation of science into clinical practice. Despite their ubiquitous use, there is a paucity of information on the perioperative care of pigs, especially for major procedures. In a series of experiments to investigate laryngeal transplantation, we combined veterinary and medical experience to develop protocols for perioperative management of pigs, including high dependency care. Novel airway management methods were developed. A pain scoring system was used to direct analgesia use. Fluid balance and electrolytes were monitored closely. Recent animals received a central venous line via the femoral vein two days prior to transplantation to facilitate blood sampling and drug delivery. Intensive monitoring and airway management were required to ensure a successful outcome. Methods for optimal perioperative care are proposed. These results will help future groups wishing to use pigs in airway research, will reduce numbers of animals used and improve animal welfare.

Efficacy of autologous fat injection laryngoplasty with an adenoviral vector expressing hepatocyte growth factor in a canine model.

OBJECTIVE: The effectiveness of autologous fat injection laryngoplasty may be reduced by resorption of injected fat tissue. The aim of the present study was to clarify the efficacy of fat injection laryngoplasty using autologous fat plus a replication-defective adenoviral vector expressing hepatocyte growth factor, regarding reduction of injected fat tissue resorption. MATERIAL AND METHODS: Four female beagle dogs were used in this study. After sedation, a direct laryngoscope was introduced to enable visualisation of the larynx. In each dog, harvested autologous fat plus an adenoviral vector expressing hepatocyte growth factor was injected into the right true vocal fold, and harvested fat plus an adenoviral vector expressing no gene was injected into the left true vocal fold. A total laryngectomy was performed one year after the intracordal fat injection. Coronal sections of the resected whole larynges were made and the following parameters assessed using light and electron microscopy: size of fat area; number of vasculoendothelial cells surrounding adipocytes; and shape of injected adipocytes in the vocal fold. RESULTS: The fat area was significantly larger and the number of vasculoendothelial cells surrounding adipocytes significantly greater in the intracordal fat injection containing adenoviral vector expressing hepatocyte growth factor, compared with the control intracordal fat injection containing adenoviral vector expressing no gene. When viewed under electron microscopy, the injected adipocytes were observed to have grafted better in the intracordal fat injection with hepatocyte growth factor adenoviral vector, compared with the control intracordal fat injection with adenoviral vector expressing no gene. CONCLUSIONS: Injection into the vocal fold of autologous fat containing an adenoviral vector expressing hepatocyte growth factor can reduce subsequent resorption of injected fat.

Airway transplantation: a debate worth having?

Laryngeal and tracheal transplantation have been proposed as treatments for irreversible airway disease for many years. Despite much research, there has only been one true laryngeal transplant reported. Although this was in many ways a success, several barriers remain before full clinical trials. There are issues over patient selection, reinnervation, immunosuppression, and cost-benefit. For the trachea, where finely tuned neuromuscular activity is not an issue, tissue-engineering probably represents the future. This overview discusses the arguments for and against laryngeal and tracheal transplantation and suggests ways of overcoming these barriers.

Composite tissue transplantation: a rapidly advancing field.

Composite tissue allotransplantation (CTA) is emerging as a potential treatment for complex tissue defects. It is currently being performed with increasing frequency in the clinic. The feasibility of the procedure has been confirmed through 30 hand transplantation, 3 facial reconstructions, and vascularized knee, esophageal, and tracheal allografts. A major drawback for CTA is the requirement for lifelong immunosuppression. The toxicity of these agents has limited the widespread application of CTA. Methods to reduce or eliminate the requirement for immunosuppression and promote CTA acceptance would represent a significant step forward in the field. Multiple studies suggest that mixed chimerism established by bone marrow transplantation promotes tolerance resulting in allograft acceptance. This overview focuses on the history and the exponentially expanding applications of the new frontier in CTA transplantation: immunology associated with CTA; preclinical animal models of CTA; clinical experience with CTA; and advances in mixed chimerism-induced tolerance in CTA. Additionally, some important hurdles that must be overcome in using bone marrow chimerism to induce tolerance to CTA are also discussed.

Donor bone marrow in laryngeal transplantation: results of a rat study.

INTRODUCTION: The concept of donor bone marrow transplantation has been successfully used in human solid organ transplantation to increase recipient chimerism. The development of recipient chimerism is associated with a decreased need for immunosuppression and even donor-specific tolerance. In this study, we attempted to augment recipient chimerism by the transfer of donor bone marrow at the time of rat laryngeal transplant. STUDY DESIGN: Experimental study in rats. METHODS: The study used a well-established semiallogeneic rat laryngeal transplant model with partial major histocompatibility complex (MHC)-mismatched Lewis-Brown-Norway donors and Lewis recipients. Donor bone marrow was introduced at transplantation via (1) intravascular injection and (2) transfer of a vascularized femoral bone graft. Recipients were treated with an established immunosuppressive regimen consisting of everolimus and anti-alphabetaTCR monoclonal antibody for a 7-day perioperative course. Animals received a 5-day boost of the same regimen at 90 days posttransplantation. Parathyroid hormone levels and histological examination were used for rejection surveillance and scoring. RESULTS: Animals treated with intravenous bone marrow injection followed by perioperative and pulsed immunosuppression commonly demonstrated early rejection (90%). Animals receiving transfer of vascularized donor femur had an average rejection score of 2.9 (scale, 1-6) at 180 days posttransplantation. Mixed-lymphocyte reaction did not demonstrate donor-specific tolerance in the latter group, and chimerism was less than 1%. CONCLUSIONS: In the rat laryngeal transplant model, donor bone marrow does not consistently lead to augmentation of peripheral chimerism using our established pulsed immunosuppression protocol. In many cases, rejection occurred earlier than animals not receiving bone marrow. This may be due to several different factors including (1) an element of graft-vs-host disease, (2) inability to establish bone marrow engraftment due to our short-term perioperative immunosuppression regimen, or (3) preferential rejection of donor bone marrow cells.

Induction with T-cell receptor antibody leads to long-term laryngeal allograft function.

PURPOSE: The use of induction therapy with alphabeta T-cell receptor (alphabetaTCR) monoclonal antibody in association with tacrolimus in an allogeneic rat laryngeal transplant model permits rigorous long-term evaluation of potential short-term synergism offered by these agents. MATERIALS AND METHODS: The allogeneic model consisted of 19 Brown Norway larynges transplanted to Lewis recipients. Treatment consisted of tacrolimus (1.2 mg/kg per day) alone and in combination with 7 days of alphabetaTCR (0.5 mL/d). Control groups consisted of untreated animals, as well as a semiallogeneic model with Lewis-Brown Norway larynges transplanted to Lewis recipients and treated with tacrolimus monotherapy. Each group consisted of 6 to 11 rats. The median duration of engraftment was 44 days (range, 14-106 days). Graft histopathology was graded according to an established 31-point scale in a blinded fashion. Long-term grafts (>75 days) were followed with serum parathyroid hormone levels. RESULTS: Untreated controls experienced almost complete rejection (mean score, 27; SD, 0). Allogeneic transplants treated with tacrolimus monotherapy experienced near-complete rejection (mean score, 25.2; SD, 2.1). Allogeneic transplants treated with combination therapy and followed for a median duration of 100 days demonstrated significantly better rejection scores than controls (mean score, 11.1; SD, 1.7; P = .003). Combination therapy was also significantly more effective in preventing acute rejection than monotherapy with tacrolimus in a semiallogeneic model (mean score, 22.1; SD, 4.6; P < .04). CONCLUSIONS: Induction therapy with tacrolimus and alphabetaTCR prevents rejection in an allogeneic model for up to 100 days. This regimen was associated with significantly better histopathologic rejection scores than untreated controls, or monotherapy with tacrolimus in allogeneic or semiallogeneic models.

[Larynx transplant: a therapeutic option for the 21st century? Literature review]. / Trasplante de la laringe: una opción terapéutica para el siglo XXI? Revisión de la literatura.

The time and space devoted recently in the mass media to the transplantation of non-vital organs, such as the hands or the face, have raised questions in our patients regarding the possibility of transplanting the larynx, an essential organ for communication. The main barriers to larynx transplantation are tissue viability of the transplanted organ, immunological tolerance and functional restoration. This review of the literature aims to update the compendium of knowledge about this procedure and to explore the prospects of larynx transplantation as a viable therapeutic option.

Larynx transplantation: laryngectomees' opinion poll.

BACKGROUND: In 1998, Strome et al. performed the first human larynx transplantation in a patient with larynx traumatism. L'Association Nationale des Mutilés de la Voix, a French association of laryngectomees, estimates that the number of laryngectomees in France has reached 20,000. The main goal of the study was to determine the potential number of patients ready to benefit from larynx transplantation in France. METHODS: We carried out a public opinion poll among 420 total laryngectomees in Rhone-Alpes, in the southeast of France. The questionnaire could be divided into three parts: demographic data; incapacities and deficiencies of the patients; and acceptability of larynx transplantation according to short-, medium-, and long-term implications. RESULTS: We received 205 answers from 420 questionnaires (48.8%). Sixty-three patients (i.e., 30.7%) would accept larynx transplantation, especially the younger patients. The patients more willingly accepted the medical constraints (e.g., medical follow-up, rehabilitation) than they did vital (after the operation or because of the treatments) or functional (risk of permanent canula, no guarantee of laryngeal voice, no guarantee of swallowing) risks. CONCLUSIONS: Even though this opinion poll has intrinsic bias and acceptance rate is low, by interpolation, larynx transplantation would interest many patients in France. Larynx transplantation is an intervention that should be proposed to a certain number of patients in the future with the help of new immunosuppressor treatments.

Postallograft donor and recipient dendritic cell trafficking in the rat larynx.

OBJECTIVES/HYPOTHESIS: Dendritic cells (DC) are potent antigen-presenting cells that instigate allograft rejection. Their migration kinetics vary depending on the type of organ transplanted. The timing of donor and recipient DC trafficking in laryngeal transplants is unknown. STUDY DESIGN: Prospective animal model. METHODS: Lewis to Brown Norway (BN) rat laryngeal allografts and BN to BN isografts were performed without immunosuppression. Recipient animals were sacrificed at seven posttransplant time points. Total DC, as well as recipient and donor DC (in allograft recipients), were enumerated in situ in the airway epithelium and subepithelium using monoclonal antibodies, immunofluorescence, confocal microscopy, and image analysis software. RESULTS: Total DC densities in both laryngeal allografts and isografts decreased to approximately 10% of their initial values in the first 3 days and then rose beyond their starting values. In allografts, there was a net efflux of donor DC, reaching a nadir by 3 to 5 days; they were identified in recipient cervical lymph nodes from 12 hours to 5 days. Recipient DC infiltrated the laryngeal allograft, reaching a maximal density by day 7. CONCLUSION: The paradigm of donor DC efflux and recipient DC influx has been confirmed in a rat laryngeal transplant model, and the allograft-specific timing of these events has been elucidated. Similarities in total DC migration between allografts and isografts suggest that this phenomenon may not be driven entirely by major histocompatibility mismatch. Further understanding of trafficking may help with the goal of manipulating DC to induce allograft tolerance in the absence of generalized immunosuppression.

Transplantation of the hand, face, and composite structures: evolution and current status.

This article reviews the world experience in the newly emerging field of composite tissue allotransplantation. These allografts contain multiple tissues that are usually musculoskeletal structures with a skin or epithelial surface, such as hand, facial structures, larynx, tongue, ear, knee/femur, abdominal wall, and penis. They represent a new transplantation field, with only a 10-year experience and just over 50 clinical cases. This review of the 10-year world experience found uniform technical success, immunologic biology, and immunosuppression regimens very similar to solid organ transplants, and success strongly correlated with adherence to guidelines for psychiatric screening, thorough preparation of patient and families, intense postoperative monitoring, and assurance of medication access. All failures reported have been caused by lapses in these parameters. This early experience shows a great potential for application of these new procedures to the most challenging reconstructive needs.