research-application-laser-induced-shock-wave-for-studying-blast

Research Application of Laser-Induced Shock Wave for Studying Blast-Induced Cochlear Injury

The ear is the organ most susceptible to explosion overpressure, and cochlear injuries frequently occur after blast exposure. Blast exposure can lead to ...

The fiber-guided carbon dioxide (CO) laser is a useful device for laryngopharyngeal surgery. The flexible CO wave-guide laser has been developed and commercially available for several years. However, the transnasal use of CO flexible wave-guided laser surgery through the instrument channel of a flexible endoscope (CO TNFLS) is not permitted in Japan. This feasibility study aimed to assess the value and the safety of an in-office CO TNFLS procedure.

Feasibility of transnasal flexible carbon dioxide laser surgery for laryngopharyngeal lesions.

In clinical N0 (cN0) cases with head and neck squamous cell carcinoma (HNSCC), a treatment selection is still controversial: elective neck dissection or watchful waiting. We focused on sentinel lymph node (SLN)-targeted therapy using the urokinase-type plasminogen activator (uPA)-dependent oncolytic Sendai virus "BioKnife." The objectives of this study were to investigate BioKnife migration into SLNs and elucidate its antitumor effect on lymph node metastases (LNM). We established an orthotopic nude mouse model of HNSCC, with LNM being frequently induced. We inoculated HSC-3-M3, human highly metastatic tongue squamous cell carcinoma cells, in the tongue of the nude mice, and after 2 weeks, we injected BioKnife into the primary tumor. We tracked BioKnife migration into the SLNs by immunostaining, RT-PCR, and an  imaging system. We also examined its antitumor effects and mechanisms through serial section analysis of lymph nodes. GFP reporter expression was clearly visible in the lymph nodes of virus groups, which corresponded to SLNs. Relative  mRNA was significantly increased in both the tongues and lymph nodes in the virus groups compared with that in the control group ( < 0.05). Serial section analysis showed that BioKnife infected cancer cells and exhibited significant antitumor effect against LNM compared with the control groups ( < 0.05). We detected apoptosis in LNM infected by BioKnife. BioKnife migrated into SLNs after its injection into the primary tumor and effectively suppressed LNM, suggesting that SLN-targeted therapy using BioKnife has great potential to provide a novel and promising alternative to elective neck dissection in cN0 patients with HNSCC.

Sentinel Lymph Node-Targeted Therapy by Oncolytic Sendai Virus Suppresses Micrometastasis of Head and Neck Squamous Cell Carcinoma in an Orthotopic Nude Mouse Model.

This study aimed to validate new staging of Japanese patients with human papillomavirus-mediated oropharyngeal cancer (HPV-OPC) and the effectiveness of transoral surgery.

Value of transoral surgery for human papillomavirus-mediated oropharyngeal cancer: validation of a new staging system in Japanese patients.

Transoral videolaryngoscopic surgery (TOVS) was developed as a non-robotic procedure for en bloc laryngo-hypopharyngeal cancer resection. Straight devices had been used for this procedure, however, some cases had difficulty to reach the lesions especially in hypopharyngeal area. To overcome this problem, technical updates to facilitate transoral manipulation were developed and long term oncological and functional results were analyzed.

Transoral videolaryngoscopic surgery for laryngeal and hypopharyngeal cancer - Technical updates and long-term results.

The aim of this study was to evaluate the efficacy and safety of local steroid injections to prevent scar contracture after transoral videolaryngoscopic surgery (TOVS) in hypopharyngeal cancer patients.

Scar contracture prevention with local steroid injections in transoral videolaryngoscopic surgery.

To reveal the patency of the anterior epitympanic space (AES) and the surgical outcomes after transcanal endoscopic ear surgery (TEES) for attic cholesteatoma with a classification of anatomical variation of the AES.

Patency of Anterior Epitympanic Space and Surgical Outcomes After Endoscopic Ear Surgery for the Attic Cholesteatoma.

Blast exposure can induce various types of hearing impairment, including permanent hearing loss, tinnitus, and hyperacusis. Herein, we conducted a detailed investigation of the cochlear pathophysiology in blast-induced hearing loss in mice using two blasts with different characteristics: a low-frequency dominant blast generated by a shock tube and a high-frequency dominant shock wave generated by laser irradiation (laser-induced shock wave). The pattern of sensorineural hearing loss (SNHL) was low-frequency- and high-frequency-dominant in response to the low- and high-frequency blasts, respectively. Pathological examination revealed that cochlear synaptopathy was the most frequent cochlear pathology after blast exposure, which involved synapse loss in the inner hair cells without hair cell loss, depending on the power spectrum of the blast. This pathological change completely reflected the physiological analysis of wave I amplitude using auditory brainstem responses. Stereociliary bundle disruption in the outer hair cells was also dependent on the blast's power spectrum. Therefore, we demonstrated that the dominant frequency of the blast power spectrum was the principal factor determining the region of cochlear damage. We believe that the presenting models would be valuable both in blast research and the investigation of various types of hearing loss whose pathogenesis involves cochlear synaptopathy.

Effect of shock wave power spectrum on the inner ear pathophysiology in blast-induced hearing loss.

Transoral surgery preserves good swallowing function in most cases, however, postoperative dysphagia sometimes leads to fatal complication such as aspiration pneumonia. We investigated the chronological changes in swallowing function have not been revealed relationship with dysphagia. The primary aim of this study was to reveal the mechanism of dysphagia following transoral surgery by analyzing chronological videofluorography (VF) findings. Moreover, the secondary aim of this study was to evaluate the relationship between mechanism of dysphagia and risk factors of patients to clarify the risk for dysphagia lead to prevention of postoperative complications.

Article	Year
Feasibility of transnasal flexible carbon dioxide laser surgery for laryngopharyngeal lesions. Auris, nasus, larynx\| PubMed ID: 30765273	2019
Sentinel Lymph Node-Targeted Therapy by Oncolytic Sendai Virus Suppresses Micrometastasis of Head and Neck Squamous Cell Carcinoma in an Orthotopic Nude Mouse Model. Molecular cancer therapeutics\| PubMed ID: 31171582	2019
Value of transoral surgery for human papillomavirus-mediated oropharyngeal cancer: validation of a new staging system in Japanese patients. The Journal of international medical research\| PubMed ID: 31516052	2019
Transoral videolaryngoscopic surgery for laryngeal and hypopharyngeal cancer - Technical updates and long-term results. Auris, nasus, larynx\| PubMed ID: 31564510	2020
Scar contracture prevention with local steroid injections in transoral videolaryngoscopic surgery. Auris, nasus, larynx\| PubMed ID: 32107068	2020
Patency of Anterior Epitympanic Space and Surgical Outcomes After Endoscopic Ear Surgery for the Attic Cholesteatoma. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology\| PubMed ID: 32941301	2021
Effect of shock wave power spectrum on the inner ear pathophysiology in blast-induced hearing loss. Scientific reports\| PubMed ID: 34282183	2021
Evaluation of chronological changes in videofluorographic findings after transoral videolaryngoscopic surgery to reveal mechanism of dysphagia. Auris, nasus, larynx\| PubMed ID: 36075789	2023

Eiko Kimura

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