Transoral robotic surgery (TORS) in Japan: procedures, advantages and current status.

Transoral robotic surgery (TORS), introduced by Weinstein et al. in 2005, has been widely adopted as a minimally invasive procedure, particularly for the treatment of patients with early stage oropharyngeal cancer. TORS is typically performed using the da Vinci Surgical System, similar to robot-assisted surgeries for other malignancies. The main difference between TORS and these other robot-assisted surgeries is that it is performed through the natural orifice of the mouth, which limits the surgical working space, and that it progresses from the lumen of the pharynx to the deeper tissues. The advantages of TORS are mainly due to the benefits of using the da Vinci Surgical System, such as three-dimensional high-definition images, magnification, multiple forceps articulation, tremor-stabilization function and motion scale function. To date, many big data and meta-analyses have shown that TORS is superior to conventional surgeries, such as open surgery, in terms of oncological outcomes, post-operative functionality and quality of life. In Japan, TORS is expected to spread across the country, as it has been covered by health insurance since April 2022. This review highlights the procedures of TORS, its unique aspects, its unparalleled advantages as a minimally invasive surgery for treating laryngeal and pharyngeal cancers, and its current status in Japan.

Biocompatibility and efficacy of collagen/gelatin sponge scaffold with sustained release of basic fibroblast growth factor on vocal fold fibroblasts in 3-dimensional culture.

OBJECTIVE: Treatment of vocal fold scarring remains challenging. We have previously reported the therapeutic effects of local injection of basic fibroblast growth factor (bFGF) in animal models and humans. A novel collagen/gelatin sponge (CGS) is capable of sustained release of bFGF, which compensates for its quick absorption in vivo, avoiding multiple injections. This study aimed to evaluate the biocompatibility and efficacy of the CGS in rat vocal fold fibroblasts prior to human trials. METHODS: Fibroblasts extracted from Sprague-Dawley rat vocal folds were seeded onto a CGS and then cultivated with bFGF at concentrations of 0, 10, and 100 ng/mL. Vocal fold fibroblast morphology, adhesion, proliferation, and gene expression were measured under these 3-dimensional conditions. RESULTS: Cells adhered to the CGS from day 1. Although no significant differences in cell morphology were detected, cell proliferation was accelerated by bFGF administration. Expression of endogenous bFGF and hepatocyte growth factor was significantly up-regulated at 10 ng/mL bFGF. The expression of procollagen I and procollagen III was significantly suppressed, whereas HAS-1 and HAS-2 were up-regulated at 10 and 100 ng/mL bFGF. CONCLUSION: The collagen/gelatin sponge is biocompatible with vocal fold fibroblasts and may be useful as a bFGF drug delivery system for the treatment of scarred vocal folds.

Endoscopic laryngo-pharyngeal surgery for elderly patients.

OBJECTIVE: Due to the rising number of elderly patients and advances in endoscopic devices, early laryngeal and pharyngeal cancers are increasingly found in elderly patients. In these cases, minimally invasive endoscopic larygo-pharyngeal surgery (ELPS) may be indicated. However, the safety and efficacy of ELPS in elderly populations has not been established. The purpose of this study was to investigate the safety, outcomes and feasibility of ELPS in very elderly patients. METHODS: Between February 2010 and April 2016, 29 pharyngeal cancerous or pre-cancerous lesions in 19 patients aged 75 years or older were treated with ELPS. Twenty-six resections were performed in total, and the patients' clinical courses were reviewed. RESULTS: Sixteen patients had multiple comorbidities and moderate to severe comorbidities were observed in 17 patients. The average surgical time and hospitalization period was 54.3min and 18.8 days, respectively. On average, oral intake began 4.4days after the procedure, and all patients eventually received nourishment by mouth; no percutaneous endoscopic gastrostomy dependency was observed. Complications included post-operative bleeding and aspiration pneumonia in two cases each, and all complications were safely managed. The 3-year overall survival rate was 90.2% and the 3-year disease-specific survival rate was 100%. CONCLUSION: ELPS was safely performed in elderly patients, suggesting that it is a feasible treatment option for pharyngeal lesions in very elderly patients.

Prevention of buccal mucosa scarring with transforming growth factor ß3.

OBJECTIVES/HYPOTHESIS: In the treatment of tumorous diseases, scarring often forms after resection or irradiation. Scarring of the buccal mucosa causes difficulty in opening the mouth and mastication, decreasing quality of life. Transforming growth factor (TGF) ß3 is an isoform of TGFß1 that is known to accelerate scarring, although it has different effects on wound healing. TGFß3 administration into wounds has been associated with improvement in the quality of healing skin in vivo. TGFß3 is also considered to be an important anti-scarring factor in buccal mucosa. The present study aimed to examine whether TGFß3 is effective for prevention and treatment of buccal mucosa scarring. STUDY DESIGN: Prospective study using an animal model. METHODS: Thirty Sprague-Dawley rats were involved in this study. We injected 0.5 mL of TGFß3 (0.005 µg/mL, 0.05 µg/mL, 0.5 µg/mL, 5 µg/mL) or saline was injected into the buccal submucosa. Fifteen minutes after the injection, the mucosa was removed down to the masseter muscle or orbicularis oris muscle layer using a 6-mm biopsy punch. Six weeks after the operation, the buccal mucosae were harvested after euthanasia. Morphologic and histologic examinations were performed. RESULTS: The administration of 0.5 µg/mL TGFß3 induced rapid re-epithelialization and suppressed scar formation. In the submucosal layer, favorable restoration of hyaluronic acid and elastin was seen in the TGFß3-treated groups compared to the saline-treated group. CONCLUSIONS: TGFß3 is considered to be effective for better restoration of extracellular matrices of injured buccal mucosa, suggesting a preventative effect of buccal mucosa scarring.

The protective efficacy of basic fibroblast growth factor in radiation-induced salivary gland dysfunction in mice.

OBJECTIVES/HYPOTHESIS: Radiotherapy is one of the most effective treatments for head and neck cancer. However, in addition to the target tumor, normal salivary glands are also included in the irradiation field. This unavoidably results in dry mouth syndrome as a side effect. In this study, the protective efficacy of basic fibroblast growth factor (bFGF) was investigated in radiation-damaged salivary glands. STUDY DESIGN: Prospective animal experiment with control. METHODS: Nine-week-old female C57BL/6 mice were divided into three groups. All mice in two of the three groups were irradiated (10 Gy) at the same time. In the bFGF-treated group, bFGF was administered to the submandibular glands for 3 consecutive days after neck irradiation. Mice in the untreated control group were administered distilled water. Mice in the third group were not irradiated and did not receive any additional treatments. Saliva flow rate and submandibular gland morphology were assessed, and the apoptotic response of irradiated submandibular glands was also evaluated. RESULTS: Administration of bFGF improved hyposalivation 8 weeks after irradiation, and histologic analysis revealed that bFGF-treated glands contained more acinar cells compared to untreated glands. The apoptotic response to irradiation, examined 1 and 2 days after irradiation, was reduced, and quantitative real-time polymerase chain reaction revealed a paracrine effect for bFGF in the glands that received bFGF treatment. CONCLUSIONS: Our study indicates that bFGF prevents salivary gland dysfunction after irradiation. The protective benefits of bFGF may be attributed to the inhibition of radiation-induced apoptosis as well as the paracrine effect it has in these tissues.

Regeneration of radiation damaged salivary glands with adipose-derived stromal cells.

OBJECTIVES: Radiotherapy is one of the most effective treatments for head and neck cancer. However, the development of dry mouth syndrome is an unavoidable side effect because, in addition to the tumor, the normal salivary glands are included in the irradiation field. Previously, we investigated the protective efficacy of basic fibroblast growth factor (bFGF) in radiation-damaged salivary glands. In this study, we investigated the efficacy of adipose-derived stromal cell (ADSC) transplantation for the regeneration of radiation damaged salivary glands. STUDY DESIGN: Prospective animal experiment with control. METHODS: ADSCs (500,000 cells isolated from green fluorescent protein mice) were transplanted into submandibular glands of C57BL/6 mice 10 weeks after 10 Gy irradiation (ADSC group). Phosphate-buffered saline was administered to mice as a control (sham group). Submandibular gland morphology and saliva flow rate were assessed just prior to transplantation and at 5 and 10 weeks posttransplantation. Quantitative RT-PCR was performed to examine the response of irradiated submandibular glands to ADSC transplantation. RESULTS: Saliva flow rate in the ADSC group was improved compared to the sham group. Although acinar cell damage was detected in both groups, the proliferation of blood vessels and other paracrine effects were observed only in the ADSC group. Additionally, the differentiation of ADSCs into blood endothelial cells and ductal cells was also observed. CONCLUSIONS: Our study indicates that ADSCs have the potential to restore salivary gland function after irradiation. The restoration of blood flow within submandibular gland tissue may explain the beneficial effects of ADSCs.

Chronic vocal fold scar restoration with hepatocyte growth factor hydrogel.

OBJECTIVES/HYPOTHESIS: Therapeutic challenges exist in the management of vocal fold scarring. We have previously demonstrated the therapeutic potential of hepatocyte growth factor (HGF) in the management of acute phase vocal fold scarring using a novel hydrogel-based HGF drug delivery system (DDS). However, the effect of HGF on matured vocal fold scarring remains unclear. The current study aims to investigate the effect of HGF-DDS on chronic vocal fold scarring using a canine model. STUDY DESIGN: Animal model. METHODS: Vocal folds from eight beagles were unilaterally scarred by stripping the entire layer of the lamina propria; contralateral vocal folds were kept intact as normal controls. Six months after the procedures, hydrogels (0.5 mL) containing 1 microg of HGF were injected into the scarred vocal folds of four dogs (HGF-treated group). Hydrogels containing saline solution were injected into the other four dogs (sham group). Histological and vibratory examinations on excised larynges were completed for each group 9 months after the initial surgery. RESULTS: Experiments conducted on excised larynges demonstrated significantly better vibrations in the HGF-treated group in terms of mucosal wave amplitude. Although phonation threshold pressure was significantly lower in the HGF-treated group compared with the sham group, no significant differences were observed in the normalized glottal gap between HGF-treated and sham groups. Histological examinations of the HGF-treated vocal folds showed reduced collagen deposition and less tissue contraction with favorable restoration of hyaluronic acid. CONCLUSIONS: Results suggest that administration of HGF may have therapeutic potential in the treatment of chronic vocal fold scarring.

Descending necrotizing mediastinitis following acute epiglottitis: a case report.

Descending necrotizing mediastinitis occurs secondary to deep neck infection, and the primary focus of infection is mostly located in the tonsil, pharynx and carious tooth. DNM following acute epiglottitis is quite rare, with only one case reported. We treated an 84-year old female with an acute epiglottitis followed by DNM. She was successfully treated by drainages with cervical surgery combined with thoracotomy and cervical surgery.