Radiotherapy is the standard treatment for head and neck squamous cell carcinoma (HNSCC), however, radioresistance remains a major clinical problem despite significant improvements in treatment protocols. Therapeutic outcome could potentially be improved if a patient's tumour response to irradiation could be predicted ex vivo before clinical application. The present study employed a bespoke microfluidic device to maintain HNSCC tissue whilst subjecting it to external beam irradiation and measured the responses using a panel of cell death and proliferation markers. HNSCC biopsies from five newly-presenting patients [2 lymph node (LN); 3 primary tumour (PT)] were divided into parallel microfluidic devices and replicates of each tumour were subjected to single-dose irradiation (0, 5, 10, 15 and 20 Gy). Lactate dehydrogenase (LDH) release was measured and tissue sections were stained for cytokeratin (CK), cleaved-CK18 (cCK18), phosphorylated-H2AX (γH2AX) and Ki‑67 by immunohistochemistry. In addition, fragmented DNA was detected using terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL). Compared with non‑irradiated controls, higher irradiation doses resulted in elevated CK18-labelling index in two lymph nodes [15 Gy; 34.8% on LN1 and 31.7% on LN2 (p=0.006)] and a single laryngeal primary tumour (20 Gy; 31.5%; p=0.014). Significantly higher levels of DNA fragmentation were also detected in both lymph node samples and one primary tumour but at varying doses of irradiation, i.e., LN1 (20 Gy; 27.6%; p=0.047), LN2 (15 Gy; 15.3%; p=0.038) and PT3 (10 Gy; 35.2%; p=0.01). The γH2AX expression was raised but not significantly in the majority of samples. The percentage of Ki‑67 positive nuclei reduced dose-dependently following irradiation. In contrast no significant difference in LDH release was observed between irradiated groups and controls. There is clear inter- and intra-patient variability in response to irradiation when measuring a variety of parameters, which offers the potential for the approach to provide clinically valuable information.

Objectives: Otosclerosis is a disease process that usually starts around the oval window, causing fixation of the stapes, resulting in conductive hearing loss. Treatment of the conductive hearing loss caused by otosclerosis consists of either rehabilitation with hearing aids or performing surgery. Given the risks of hearing impairment and vertigo associated with the surgery, there has been a desire to advance the practice to minimize the complications. The so-called “non-contact” or “no touch” techniques with the use of various lasers are in current practice. This review article will cover the surgical aspects, the theory behind laser and the various types used in stapes surgery. It will also review the evidence of laser versus conventional stapes surgery and the comparison of different laser types. Methods: A literature search up to December 2019 was performed using Pubmed and a nonsystematic review of appropriate articles was undertaken. Keywords used were stapes, surgery, laser, stapedectomy, and stapedotomy. Results: Overall, there is no evidence to say laser fenestration is better than conventional fenestration techniques; however, with the micro drill, there is an increased risk of footplate fracture and sensorineural hearing loss. There is an increased risk of tinnitus with the laser compared to conventional techniques. Studies have favored the CO2 laser over potassium titanyl phosphate (KTP) and erbium-doped yttrium aluminium garnet (Erbium-YAG) lasers for postoperative closure of the air-bone gap; and KTP laser has less thermal, mechanical, and sound effects compared with the thulium and carbon dioxide (CO2) lasers. There is an increased risk if inner ear complications with the thulium laser. Conclusions: It can be deduced that theoretically and practically, the thulium laser is less safe compared to the KTP and CO2 lasers. The choice of laser used depends on the surgeon’s preference, as well as availability, cost, side effects profile, as well as ease of use.

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