De-Epithelialized Viable Tracheal Allotransplantation Without Immunosuppressants: 5-Year Follow-Up

OBJECTIVE

Tracheal transplantation could be a better option for patients with long segmental laryngotracheal stenosis or defects, but the need for immunosuppressants limits its widespread use due to the antigenicity of the tracheal epithelium. Chemically treated or cryopreserved nonviable tracheal allografts have no immunogenicity but lead to necrosis and stenosis in long-term outcomes. The present report describes the 5-year outcomes of de-epithelialized viable tracheal allotransplantation without immunosuppressants in a patient with severe laryngotracheal stenosis.

METHODS

The recipient was a 47-year-old female with relapsing polychondritis affecting the larynx and cervical trachea and producing a 5 cm long stenosis that could not be repaired using resection and anastomosis. A tracheal allograft was obtained from a 45-year-old male donor and treated with a combination of 3% sodium dodecyl sulfate (SDS) and organ preservation solution for 138 hours. The allograft was revascularized by heterotopical implantation in the infrahyoid muscles of the recipient for 3 months and then transplantation to the laryngotracheal defect with a split-thickness skin graft sutured to the lumen and a silicon T-tube. No immunosuppressants were used postoperatively.

RESULTS

The allograft was de-epithelialized, and most of the cartilage rings remained viable after the treatment. The allograft was revascularized, viable, and mechanically stable after 3 months of heterotopic implantation. No apparent signs of rejection or destruction were observed. The T-tube was removed, and the internal lining of the allograft was repopulated 4 months after orthotopic transplantation, despite the skin graft necrotizing at 2 weeks. Endoscopy and computed tomography showed a patent airway 5 years after orthotopic transplantation. The patient was able to resume her usual quality of life.

CONCLUSION

The present study demonstrates that transplantation of the de-epithelialized viable tracheal allograft without immunosuppressants is safe and promising for patients with long laryngotracheal stenosis or defects, especially for those with malignant tumor resections.

Hemicricoidectomy with modified rotational thyro-crico-tracheal anastomosis: a newborn in the family of crico-tracheal resection and anastomosis techniques

Objective

The aim of the present study is to describe our novel surgical technique of hemicricoidectomy and reconstruction with modified rotational thyro-crico-tracheal anastomosis for the treatment of non-squamous cell subglottic tumours. The procedure has been defined as Type E crico-tracheal resection and anastomosis (CTRA) following the University of Brescia (C)TRA classification introduced elsewhere.

Methods

A detailed anatomical step-by-step dissection was reproduced and illustrated on a cadaveric laryngo-tracheal specimen. Moreover, oncological and functional outcomes of the first 5 patients who underwent Type E CTRA at our Institution between October 2016 and September 2022 are described.

Results

Three patients underwent Type E CTRA for cricoid chondrosarcoma (CS) and 2 patients for subglottic adenoid cystic carcinoma (ACC). No post-operative complication was reported. All patients maintained intact oral intake and an intelligible voice at discharge. All but one patient with obstructive sleep apnoea hypopnea syndrome and lung comorbidity were successfully decannulated before discharge. At the last follow-up (April 2023), one patient experienced local recurrence of CS that was still amenable to conservative treatment by transoral debulking, while the remaining patients were free of disease.

Conclusions

With the proper indications, Type E CTRA is a feasible and effective conservative surgical technique for selected non-squamous cell subglottic tumours.

Establishing safe high hydrostatic pressure devitalization thresholds for autologous head and neck cancer vaccination and reconstruction

High hydrostatic pressure specifically devitalizes cells and tissues without major changes in their molecular structure. Hence, high hydrostatic pressure may enhance the development of whole-cell anti-tumor vaccines, representing tumor heterogeneity and thus (neo-) antigen diversity. Moreover, safe devitalization of tumor-infiltrated supporting tissue may facilitate reimplantation for functional reconstruction. However, precise high hydrostatic pressure thresholds for safe cancer cell killing are unknown. Here, we show that high hydrostatic pressure of at least 450 MPa is necessary to safely devitalize head and neck squamous cell cancer. A pressure of 300 MPa, which has been used frequently in cancer vaccine preparation, resulted in partial devitalization with 27% live cells in flow cytometry and 4% remaining autofluorescence in cell culture after one week. The remaining cells could form vital tumors in the chorioallantoic membrane assay. In contrast, 450 MPa killed all cells in vitro and prevented tumor outgrowth in ovo. The effectiveness of 450 MPa was attributed to the induction of DNA double-strand breaks, independent of apoptosis, autophagy, or methuosis. Furthermore, 450 MPa continued to induce immunogenic cell death. Our results demonstrate that 450 MPa of high hydrostatic pressure induces safe and sustained devitalization of head and neck cancer cells and tissues. Because of the heterogeneity in pressure resistance, we propose our approach as a starting point for determining the precise thresholds for other cancer entities. Further studies on head and neck cancer should focus on immunological co-cultures, combinations of immune checkpoint inhibition, and accurate anatomical reconstruction with pressure-treated autografts.

Human Tracheal Transplantation

Long-segment tracheal airway defects may be congenital or result from burns, trauma, iatrogenic intubation damage, or tumor invasion. Although airway defects <6 cm in length may be reconstructed using existing end-to-end reconstructive techniques, defects >6 cm continue to challenge surgeons worldwide. The reconstruction of long-segment tracheal defects has long been a reconstructive dilemma, and these defects are associated with significant morbidity and mortality. Many of these defects are not compatible with life or require a permanent extended-length tracheostomy that is fraught with complications including mucus plugging and tracheoesophageal fistula. Extensive circumferential tracheal defects require a reconstructive technique that provides a rigid structure able to withstand the inspiratory pressures, a structure that will biologically integrate, and contain functional ciliated epithelium to allow for normal mucociliary clearance. Tracheal transplantation has been considered the reconstructive "Holy Grail;" however, there has been a long-held scientific dogma that revascularization of the trachea was not possible. This dogma stifled research to achieve single-staged vascularized tracheal transplantation and prompted the introduction of many creative and inventive alternatives. Throughout history, alloplastic material, nonvascularized allografts, and homografts have been used to address this dilemma. However, these techniques have largely been unsuccessful. The recent introduction of a technique for single-staged vascularized tracheal transplantation may offer a solution to this dilemma and potentially a solution to management of the fatal tracheoesophageal fistula.

Investigation of the In Vitro and In Vivo Biocompatibility of a Three-Dimensional Printed Thermoplastic Polyurethane/Polylactic Acid Blend for the Development of Tracheal Scaffolds

Tissue-engineered polymeric implants are preferable because they do not cause a significant inflammatory reaction in the surrounding tissue. Three-dimensional (3D) technology can be used to fabricate a customised scaffold, which is critical for implantation. This study aimed to investigate the biocompatibility of a mixture of thermoplastic polyurethane (TPU) and polylactic acid (PLA) and the effects of their extract in cell cultures and in animal models as potential tracheal replacement materials. The morphology of the 3D-printed scaffolds was investigated using scanning electron microscopy (SEM), while the degradability, pH, and effects of the 3D-printed TPU/PLA scaffolds and their extracts were investigated in cell culture studies. In addition, subcutaneous implantation of 3D-printed scaffold was performed to evaluate the biocompatibility of the scaffold in a rat model at different time points. A histopathological examination was performed to investigate the local inflammatory response and angiogenesis. The in vitro results showed that the composite and its extract were not toxic. Similarly, the pH of the extracts did not inhibit cell proliferation and migration. The analysis of biocompatibility of the scaffolds from the in vivo results suggests that porous TPU/PLA scaffolds may facilitate cell adhesion, migration, and proliferation and promote angiogenesis in host cells. The current results suggest that with 3D printing technology, TPU and PLA could be used as materials to construct scaffolds with suitable properties and provide a solution to the challenges of tracheal transplantation.

Survival outcomes in laryngeal chondrosarcoma: a systematic review

Laryngeal chondrosarcomas (LCS) are rare lesions that behave as locally aggressive tumours, producing symptoms such as dysphonia, dyspnoea, dysphagia and hoarseness. Different approaches for the treatment of LCS have been described in the literature. The main purpose of this investigation was to find all cases of LCS published to date and analyse management data and survival outcomes. In December 2020, a systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Provider Enrollment, Chain, and Ownership System (PECOS) method including articles published up to this date on different aspects of LCS. The search included the terms larynx, laryngeal, chondrosarcoma. A total of 148 articles were included in this systematic review describing 381 cases of LCS. Dyspnoea was the most reported symptom followed by hoarseness and neck mass sensation. Cricoid cartilage was the most usual location. Survival rate was influenced by both surgical technique (log-rank = 11.7; p = 0.008) and the degree of tumour histologic differentiation (log-rank = 18.3; p = 0.003).

The glottic-subglottic laryngectomy: Surgical technique, oncological, and functional outcomes

OBJECTIVES

The aim of this article was to describe the surgical technique and report the oncological and functional outcomes of the partial glottic-subglottic laryngectomy (GSL).

METHODS

A retrospective review of the clinical charts of patients who underwent GSL for laryngeal cancer from 1989 to 2020 at the Otolaryngology Unit of the Vittorio Veneto Hospital, a referral center for laryngeal cancer treatment.

RESULTS

The present article considered 36 patients who were submitted to GSL for laryngeal cancer. The pathological exam found squamous cell carcinoma (SCC) in 16 cases, adenoid-cystic carcinoma (ACC) in 9 cases, laryngeal chondrosarcoma in 8 cases, 1 giant cell carcinoma, 1 carcinosarcoma, and 1 metastasis of colon adenocarcinoma. Considering the 16 SCC cases we observed a recurrence rate of 31%, the overall survival (OS) and disease-specific survival (DSS) were 75%. The 9 ACC cases had a recurrence rate of 23% and OS/DSS of 88%. In the 8 chondrosarcomas no relapses were reported and the OS/DSS were 100%. Among the patients without recurrence of the disease, a definitive decannulation was achieved in 21 cases (75%).

CONCLUSIONS

The GSL represents a valid alternative to total laryngectomy in selected cases of laryngeal cancer involving the glottic and subglottic regions.

The History of Engineered Tracheal Replacements: Interpreting the Past and Guiding the Future

The development of a tracheal graft to replace long-segment defects has thwarted clinicians and engineers alike for over 100 years. To better understand the challenges facing this field today, we have consolidated all published reports of engineered tracheal grafts used to repair long-segment circumferential defects in humans, from the first in 1898 to the most recent in 2018, totaling 290 clinical cases. Distinct trends emerge in the types of grafts used over time, including repair using autologous fascia, rigid tubes of various inert materials, and pretreated cadaveric allografts. Our analysis of maximum clinical follow-up, as a proxy for graft performance, revealed that the Leuven protocol has a significantly longer clinical follow-up time than all other methods of airway reconstruction. This method involves transplanting a cadaveric tracheal allograft that is first prevascularized heterotopically in the recipient. We further quantified graft-related causes of mortality, revealing failure modes that have been resolved, and those that remain a hurdle, such as graft mechanics. Finally, we briefly summarize recent preclinical work in tracheal graft development. In conclusion, we synthesized top clinical care priorities and design criteria to inform and inspire collaboration between engineers and clinicians toward the development of a functional tracheal replacement graft. Impact statement The field of tracheal engineering has floundered in recent years due to multiple article retractions. However, with recent advances in biofabrication and tissue analysis techniques, the field remains ripe for advancement through collaboration between engineers and clinicians. With a long history of clinical application of tracheal replacements, engineered tracheas are arguably the regenerative technology with the greatest potential for translation. This work describes the many phases of engineered tracheal replacements that have been applied in human patients over the past 100 years with the goal of carrying forward critical lessons into development of the next generation of engineered tracheal graft.

Salvage surgery for residual or recurrent laryngeal squamous cell carcinoma after (Chemo)radiotherapy: Oncological outcomes and prognostic factors

Nonsurgical primary treatment of early and advanced laryngeal squamous cell carcinoma, employing radiotherapy with or without chemotherapy, is considered a standard of care in many centers throughout the world. When patients have persistent or recurrent disease after non-surgical treatment, salvage surgery is frequently the only remaining potentially curative treatment. Depending on the extent of the residual/recurrent disease, different surgical salvage options are at the surgeon's disposal. In selected cases with limited local disease, salvage transoral laser microsurgery, transoral robotic surgery and open partial laryngectomies can be employed to achieve cure while preserving laryngeal function. For more advanced cases total laryngectomy is necessary. Identifying situations with unacceptable results from surgical salvage may guide future therapies.

The current status and outlook of trachea transplantation

PURPOSE OF REVIEW

The trachea is an enigmatic organ due to its complex morphology. Although circumferential tracheal defects are extremely difficult to repair with autologous tissue or with an allotransplant, the trachea has been touted as the first organ that could be regenerated. This review provides a comprehensive evaluation of the published evidence in tracheal tissue replacement surgery.

RECENT FINDINGS

In recent years, reports of successful tracheal regeneration have attracted great interest. Despite descriptions of the trachea as a perhaps uniquely regeneratable tissue since 2008, critical reporting provided insights into the more complex realities of tracheal regeneration attempts and led to the retraction of some articles making tracheal regeneration claims. Allotransplantation of the trachea is hindered by numerous difficult obstacles. The most promising approach developed thus far for difficult-to-repair patch airway defects is tracheal allotransplantation, which allows for tapering and withdrawal of immunosuppressive therapy.

SUMMARY

Restoration of a long-segment circumferential tracheal defect remains an unmet challenge. Future clinical studies require thoroughly documented visual evidence of outcomes to reduce confusion surrounding tracheal replacement and to prevent future scandals like those seen previously in the tracheal regeneration story. VIDEO ABSTRACT: http://links.lww.com/COOT/A6.

Open-neck organ preservation surgery for hypopharyngeal cancer: indications, techniques, limits, and outcomes

PURPOSE OF REVIEW

To appraise the practice and role of open-neck organ preserving surgery for hypopharyngeal squamous cell carcinoma and to update the current indications, techniques, limits, and outcomes.

RECENT FINDINGS

The role of primary surgery for hypopharyngeal carcinoma has shifted over the past two decades to primary nonsurgical management with the use of induction or concurrent chemoradiotherapy. The preferred and most suitable tumours for open-neck surgery are the small-volume T stage diseases, with small to medium-volume neck metastases, however such patients are exceedingly rare. Nonetheless, more advanced tumours with cartilage invasion, vocal cord paralysis, or located at piriform apex and postcricoid area, previously unsuitable for open-neck organ preserving surgery, can now be excised and repaired, minimizing morbidity and improving quality of patients' life. Much of this surgical progress has been developed by innovative surgeons using free tissue transfer, accurate placement surgery, reconstruction of a neoglottis, and perfecting the pharyngoesophageal anastomosis. Current practice of open-neck organ preserving surgery for hypopharyngeal carcinoma has been mainly reported in Asia: Korea, Taiwan, Japan, and China.

SUMMARY

There are some patients who are deemed unsuitable and/or unwilling for current treatment by nonsurgical approaches, and open-neck organ preserving laryngopharyngeal surgery may be a more suitable alternative than selecting a 'lesser or modified' chemo or bioradiotherapy regimen, resulting in a prolonged quantity and quality of life.

Aortic allografts: final destination?-a summary of clinical tracheal substitutes

The patient population in desperate need for an airway substitute are individuals with long segment tracheal defects that are considered, technically, inoperable. Regardless of the underlying etiology, benign or malignant growing processes, this patient category enters a palliative setting or require tracheal transplantation. Different airway substitutes have been categorized by Grillo as follows; tracheal transplantation, autogenous tissue, non-viable tissue, tissue-engineering and foreign materials. These fields have been explored in the past in animal models and in clinical patients. Research on airway replacement has been exposed to a level of controversies in the past years. The field has been turbulent and apocryphal. In particular, the area of tissue-engineering using stem cells has suffered from a major set-back leaving scientists, clinicians and ethical committees skeptical. Recently, a hopeful study emerged using aortic allografts as tracheal substitutes in patients with airway defects. The initial results seem promising and reliable. The developments of the field at this point seem striking and hopeful. The focus of this review is to shed light on developments in the field of aortic allografts as substitute for tracheal replacement.

Conservative surgery for laryngeal chondrosarcoma: a review of the most recently proposed approaches

PURPOSE OF REVIEW

The aim of this study was to describe the most recent technical nuances for resection and reconstruction of Grade 1 and 2 laryngeal chondrosarcomas, with a special emphasis on those located at the level of the cricoid plate, which is the site of origin of the vast majority of these rare tumours.

RECENT FINDINGS

Even though inherently based on retrospective small clinical series or anecdotal case reports, a number of studies have been recently published focusing on conservative transoral and open-neck surgical procedures aimed at an oncologically sound removal of the tumour together with organ and function preservation. The open-neck conservative approaches herein reported can be roughly distinguished in those achieving a primary airway reconstruction by a tracheo-hyoido-epiglottopexy or an end-to-end crico-tracheal, thyro-crico-tracheal or thyro-tracheal anastomosis, and those requiring a single or double-staged transposition of different microvascular flaps, with or without cartilaginous graft insertion, to reconstruct a subtotal/total cricoidectomy and obtain a rigid and stable subglottic airway.

SUMMARY

No meaningful comparison in terms of oncologic and functional outcomes is still possible among the currently available conservative surgical strategies, due to the rarity of laryngeal chondrosarcomas and the heterogeneity of treatments proposed in the literature. However, a reasonable algorithm to approach this difficult clinical entity according to its site of origin and extent of cricoid circumference involved is herein presented.

Salvage Transoral Laser Microsurgery for Radiorecurrent Laryngeal Cancer: Indications, Limits, and Outcomes

Purpose of Review

The aim of this report is to identify relevant literature reports on salvage transoral laser microsurgery (TLM); to consider its oncologic and functional outcomes, as well as reported complications; and to address indications and limitations of salvage TLM.

Findings

The weighted average of local control after first salvage TLM was 57%. Repeated TLM procedures for second or third recurrences were required in up to 41% of cases, resulting in a weighted average of local control with TLM alone of 67%. The rate of definite laryngeal preservation was 73%. The ultimate local control rate, including cases that required total laryngectomy, was 90%. The overall complication rate after salvage TLM was 14%.

Summary

Salvage TLM of radiorecurrent laryngeal cancer yields excellent oncologic outcomes. Serious complications are scarce, hospitalization times are short, and functional outcomes in terms of voice and swallowing are favorable when compared to open conservation laryngeal surgery. The key to success is an optimal patient selection.

Reconstruction of defects of the trachea

The trachea has a complex anatomy to fulfill its tasks. Its unique fibro-cartilaginous structure maintains an open conduit during respiration, and provides vertical elasticity for deglutition, mobility of the neck and speech. Blood vessels pierce the intercartilaginous ligaments to perfuse the ciliated epithelium, which ensures effective mucociliary clearance. Removal of a tracheal segment affected by benign or malignant disease requires airtight restoration of the continuity of the tube. When direct approximation of both tracheal ends is no longer feasible, a reconstruction is needed. This may occur in recurrent short-segment defects in a scarred environment, or in defects comprising more than half the length of the trachea. The resulting gap must be filled with vascularized tissue that restores the mucosal lining and supports the semi-rigid, semi-flexible framework of the trachea. For long-segment or circular defects, restoration of this unique biomechanical profile becomes even more important. Due to the inherent difficulty of creating such a tube, a tracheostomy or palliative stenting are often preferred over permanent reconstruction. To significantly improve and sustain quality of life of these patients, surgeons proposed innovative strategies for complex tracheal repair. In this review, we provide an overview of current clinical applications of tracheal repair using autologous and allogenic tissues. We look at recent advances in the field of tissue engineering, and the areas for improvement of these first human applications. Lastly, we highlight the focus of our research, in an effort to contribute to the development of optimized tracheal reconstructive techniques.

Tracheal tissue-engineering: in-vivo biocompatibility of mechanically-stripped allogenic rabbit trachea with autologous epithelial covering

BACKGROUND

Successful trachea transplantation comprises the use of biocompatible constructs with little immune-reactivity, submucosal revascularization and creation of an epithelial covering. Allogenic chondrocytes might be protected from an overt immune-response due to physical isolation. Our aim was to evaluate in-vivo biocompatibility of allotracheae, stripped of their highly-immunogenic inner lining. Secondly, we established whether these constructs might serve as suitable scaffolds for autologous epithelial grafting.

METHODS

Mucosa and submucosa of 12 rabbit donor tracheae were mechanically peeled off. Cartilage was covered with Integra™ regeneration-template. Constructs were implanted within the recipient's lateral thoracic artery flap. Integra of 6 revascularized allotracheae was grafted with autologous buccal mucosa. Macroscopical, histological analysis and immunohistochemistry were performed.

RESULTS

Revascularization and buccal grafting was incomplete in the first 2 circular constructs. To enhance blood-vessel outgrowth, the following 10 transplants were opened longitudinally before implantation. Integra revascularized well. Grafted tracheae showed satisfactory mucosa-adherence, albeit with invasion of migrating epithelium within the Integra-scaffold.

CONCLUSIONS

Mechanically-stripped allotracheae exhibited beneficial biocompatibility up to two months. This approach might open doors in the treatment of long-segment tracheal pathologies of which immunosuppression is contra-indicated. Thickness of this layered construct limited practical feasibility of orthotopic transfer, though with further refinements, a clinically-useful transplant could be created.