The phrenic nerve; the forgotten nerve in head and neck surgery.

BACKGROUND: Neck dissection is a commonly performed procedure for oncologic control of head and neck malignancy. With contemporary modified radical and selective neck dissections, haematoma, wound infection, tissue necrosis, chyle leak and injury involving the marginal mandibular, hypoglossal, vagus or accessory nerves are commonly described complications. Although the phrenic nerve courses within the surgical planes explored during a neck dissection and has a vital function in innervating the diaphragm, few studies have been performed to investigate the exact incidence of post-operative phrenic nerve paresis. This study aims to review the literature as to the rate of phrenic nerve injury following neck dissection. METHODS: A systematic literature review was conducted from 2000 to 2022 including studies reporting on phrenic nerve paresis following neck dissection. RESULTS: In total, 11 studies were included. The reported rate of immediate post-operative phrenic nerve paresis ranged from 0% to 5.3%, with an average rate of 0.613% (12/1959). The reported rate of phrenic nerve paresis at follow-up (1 month-127 months) ranged from 0% to 4.7%, with an average rate of 1.035% (5/483). There were no cases of bilateral phrenic nerve paresis reported in this period. CONCLUSIONS: Phrenic nerve paresis is an uncommon complication following neck dissection, often asymptomatic and potentially underreported. Bilateral phrenic nerve paresis is exceedingly rare. Injury can be avoided by staying superficial to the prevertebral fascia when dissecting around the anterior scalene muscle. Routine phrenic nerve integrity monitoring is not commonly utilized but may aid intra-operative phrenic nerve identification or confirmation of function.

The efficacy and safety of high-intensity focused ultrasound in the treatment of benign thyroid nodules: A systematic review and meta-analysis from 1990 to 2021.

INTRODUCTION: To date, there have only been 2 systematic reviews, and 1 systematic review and meta-analysis on high-intensity focused ultrasound (HIFU) for benign thyroid nodules. The present systematic review and meta-analysis seeks to evaluate the efficacy and safety of HIFU in the treatment of benign thyroid nodules. METHODS: Pubmed, Embase and Cochrane databases were searched for relevant studies from 1990 to 2021. Nine studies were included in the systematic review and 6 in the meta-analysis. Pooled volume reduction rates (VRRs) at 3, 6 and 24 months after HIFU were assessed. RESULTS: This systematic review and meta-analysis showed that pooled VRRs at 3, 6, and 24 months after HIFU were 42.14 (95% confidence interval [CI] 28.66-55.62, I2=91%), 53.51 (95% CI 36.78-70.25, I2=97%) and 46.89 (95% CI 18.87-74.92, I2=99%), respectively. There was significant heterogeneity in the pooled VRRs at 3, 6 and 24 months after HIFU. No studies recorded complete disappearance of the nodules. Common side effects included pain, skin changes and oedema. There were no major complications except for transient vocal cord paralysis and voice hoarseness (0.014%) and transient Horner syndrome (0.5%). CONCLUSION: HIFU may be an effective and safe alternative treatment modality for benign thyroid nodules. Larger clinical trials with longer follow-up are needed to evaluate the effectiveness of HIFU in treating benign thyroid nodules.

Risk stratification of parotid neoplasms based on intraoperative frozen section and preoperative fine needle aspiration cytology.

PURPOSE: This study aims to determine the relationship of frozen section (FS) to final histology and determine how incorporating FS may change preoperative malignancy risk estimates based on preoperative fine needle aspiration cytology (FNAC). The secondary aim is to determine if FS is useful in influencing intraoperative decision-making. METHODS: Retrospective review of 426 intraoperative FS for parotidectomies performed for primary parotid lesions. RESULTS: Risk of malignancy with a benign FS was 2.5%, with indeterminate 36.1%, and with malignant 100%. Incorporating FS to fine needle aspiration for cytology helped to stratify malignancy risk especially in the Milan categories of atypia of undetermined significance, neoplasm of uncertain malignant potential and non-diagnostic categories, where a malignant FS increased malignancy risk significantly. FS was only able to identify 11% of high-risk histological subtypes for which a neck dissection would be recommended. CONCLUSIONS: FS may be used to stratify malignancy risk intraoperatively but has limited utility in clinical decision-making to perform a neck dissection and more extensive parotid resection in high-risk histological subtypes.

Myoclonus From Intoxication by Bismuth Iodoform Paraffin Paste (BIPP) Nasopharyngeal Packing.

Bismuth iodoform paraffin paste (BIPP) gauze is widely used as an antiseptic wound packing in otolaryngology, head, and neck surgery. Uncommonly, BIPP can cause intoxication. Our report highlights an elderly patient who developed encephalopathy and overt myoclonus after nasopharyngectomy secondary to intoxication by the components of the BIPP gauze. The patient's impaired renal function, the amount of BIPP packing and the extensive nature of his wound likely predisposed him to BIPP toxicity. The myoclonus and delirium resolved promptly after removal of the BIPP packs. Clinicians should be aware of the clinical features of BIPP intoxication because of its common usage.

Comparison of Outcomes of Intra-operative Neuromonitoring of Recurrent Laryngeal Nerve Versus Visualisation Alone during Thyroidectomies: A Singapore Experience.

INTRODUCTION: Although intra-operative neuromonitoring (IONM) has become commonly used to identify the recurrent laryngeal nerve (RLN) during thyroid surgeries, its value is still debatable. This study aimed to evaluate the outcomes of thyroid surgery using IONM versus visualisation alone (VA). METHODS: We conducted a retrospective analysis of all the open thyroidectomies performed by the otolaryngology department in a tertiary institution in Singapore (Khoo Teck Puat Hospital) from 1 January 2014 to 31 December 2018. There were 301 nerves-at-risk (NAR), 139 in the IONM group and 162 in the VA group. The primary outcome measure was the incidence of RLN injury and the secondary outcome measure was operative duration. RESULTS: There were 33 NAR with immediate post-operative RLN injury, of which 7 had permanent (>6 months) injury. There were minor improvements in the respective rates of immediate and permanent injury in the IONM group (7.9%, 0.7%) compared to the VA group (13.6%, 3.8%), but these were not statistically significant (P=0.14, 0.13). The average operative duration of total thyroidectomies in the IONM group was 37 minutes shorter than in the VA group, but the difference was not statistically significant (P=0.40). CONCLUSION: The current study shows that the use of intra-operative neuromonitoring shows a tendency towards better RLN outcome and operative duration for total thyroidectomies, but the study may be too small to demonstrate a statistical difference.