ENT

What is the relationship between the recurrent laryngeal nerve (RLN) and the common carotid artery (CCA) during a thyroidectomy?

· The descending branch of the nerve travels between the deep and middle layers of the masseter muscle and angles toward the oral commissure.

Identification of Masseteric Nerve. · Found within the sub-zygomatic triangle bound by the zygomatic arch, frontal branch of the facial nerve, and the anterior temporomandibular joint. · Can be localised to 3cm anterior to the tragus &1cm below the zygomatic arch.

Calcium Bioavailability (BA). Calcium Carbonate (CC) • Alkaline • BA 15-40% • Low solubility, &inconsistent absorption rate Calcium Citrate • Acidic • Requires less stomach acid for absorption • BA~ 40% • Absorbed 22% (empty stomach) to 27% (food) better than CC

Head & Neck CUP Immunohistochemistry • p16 - surrogate for HPV-associated oropharyngeal ca • Epstein-Barr virus-encoded RNA, associated with nasopharyngeal ca • Calcitonin for medullary thyroid ca • Thyroid-transcription factor to distinguish from lung SCC (Lung is positive)

• Overexpression of p16 is usually localised to tumour cell nuclei & cytoplasm • p16 staining localised only to the cytoplasm is considered nonspecific and thus non-diagnostic. (3/3)

• E2F upregulates p16 making it a marker for HPV induced cancers • Not only is p16 a cheap and simple test to execute; it is an independent prognosticator of outcome • p16 overexpression is diffuse (≥75%) tumour expression, with moderate (+2/3) staining intensity. (2/3)

p16 testing and Head and Neck Cancer. • Immunohistochemistry for over-expression of tumour suppressor protein p16 (cyclin-dependent kinase 2A) is a surrogate biomarker for HPV-mediated cancer • HPV-E7 oncoprotein binds to Retinoblastoma blocking it from inactivating E2F (1/3)

ANSWER = RLN goes posterior to CCA.

What is the relationship between the recurrent laryngeal nerve (RLN) and the common carotid artery (CCA) during a thyroidectomy?

• Most commonly injured nerve in rhytidectomy is Great Auricular nerve. • Emerges from the posterior border of the sternocleidomastoid muscle at a point 6.5 cm inferior to the external auditory meatus, also known as McKinney's point.

Salvage laryngectomy complications Hasan Z et al Systematic review Eur J Surg Oncol 2017 · 50 studies, n=3292 · Overall complication rate = 67.5% · Pharyngocutaneous fistula (28.9%) · Wound infection (14.1%) · Pharyngeal stenosis (14.3%) · Bleeding (5.9%) · Dysphagia (18.6)

ANSWER = TRUE. The normal reference range for PTH is affected by Vitamin D and a comment on PTH should only be inferred following threshold achievement of Vitamin D (20-30ng/mL -dependent on source of guidelines).

The normal reference range of parathyroid hormone is affected by Vitamin D depletion.

Skeletal Actions of PTH 1. Immediate: Mobilization of readily available calcium from skeletal stores. 2. Delayed: Activation of bone resorption leading to more calcium and phosphate release. (Talmage and Elliott 1958)

Incidence of Laryngeal Malignancy in a 3-year follow up of laryngeal leukoplakia biopsies. No dysplasia ~4% Mild/moderate dysplasia ~ 10% Severe dysplasia/carcinoma in situ ~18%

Curative management considerations of locally advanced & metastatic cutaneous squamous cell carcinoma. Claveau et al. 2020

Transoral surgery. Electrosurgical units have been shown to ignite and propagate fires at 15 W and when the fraction of inspired oxygen (FiO2) is greater than 50%.

Distant metastasis (DM) in HPV positive oropharyngeal SCC. • Overall DM rate is 7.0% (95% CI: 5.9–8.2) • T3 or T4 disease associated with a 5-fold (95% CI: 1.92–12.40) risk of DM compared to T1 or T2 disease • Most common sites: Lung (61%)>Abdomen>Skin Crossley et al. 2022

What is my risk of oropharyngeal HPV SCC? D'Souza 2017

At risk populations of oropharyngeal HPV SCC. 1. Sexual exposure to oral HPV (Men >5 lifetime oral sexual partners, Women >2) 2. Persistent oral HPV DNA 3. Persistent HPV E6 antibodies 4. Positive smoking status