Malignancy Rates by Bethesda Subcategory in the Pediatric Population.

INTRODUCTION: While the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is the most widely used method for categorizing thyroid nodules, its applicability to children is often debated. We describe our institution's experience utilizing the TBSRTC and examine the rates of malignancy in our population. METHODS: We conducted a retrospective chart review of eligible patients undergoing primary thyroidectomy at a high-volume tertiary care pediatric hospital. All patients had pre-operative fine needle aspiration. RESULTS: Of the 112 patients in our cohort, 85 (76%) were female. The median age was 15.1 years. The patients were divided into groups based on the Bethesda categorization of the fine needle aspirations of their nodules. The percentages of patients whose resection specimens showed evidence of malignancy on the surgical pathology reports were recorded as follows: category I (n = 5): 20%, category II (n = 11): 0%, category III (n = 30): 17%, category IV (n = 13): 31%, category V (n = 17): 94% and category VI (n = 36): 100%. CONCLUSION: Our findings indicate that the malignancy rates at our institution are comparable to those reported by other high-volume studies. When compared with the 2017 TBSRTC data, we found that our results were similar in many categories, with the exception of categories I and V.

Incidence of thymic tissue in pediatric thyroidectomy.

OBJECTIVES: The nuances in the technical approach to pediatric thyroidectomy have been sparsely reported in the literature. No previous studies have reported on the rates of unintentional thymic tissue excision during pediatric thyroidectomy. In this study, we sought to describe the rates of thymic tissue excision noted on surgical specimens from pediatric thyroidectomies and investigate any correlations with preoperative factors and long-term outcomes. METHODS: A retrospective chart review was conducted of patients who underwent thyroidectomy at a tertiary care children's hospital between January 2010 and October 2020. Presence of thymic tissue (PTT) was defined as any pathologist-documented evidence of thymic tissue in the surgical specimen. Patient characteristics, operative details, and disease related datapoints were investigated for any correlation with PTT. RESULTS: Of the 209 patients who underwent thyroidectomy in the study period, 53 (25%) had PTT. After conducting a stepwise multivariate analysis, those with a concomitant central neck dissection had 3.3 times the odds of having PTT as compared to those with no neck dissection (p = 0.013, 95%CI: 1.3, 8.3). Additionally, patients with evidence of incidental parathyroidectomy had 8.99 times the odds of also having PTT as compared to those without IPE (p < 0.001, 95%CI: 4.0, 20.1). CONCLUSION: This is the first report analyzing the rate of thymic tissue excision during pediatric thyroidectomy. Thyroid surgeons should be prepared to encounter thymic tissue during pediatric cases and be aware of its associated risk of incidental parathyroid gland excision and dissection of tissue beyond intended surgical limits.

Thyroid tumor ratio: Improving the assessment of the impact of size in pediatric thyroid cancer.

BACKGROUND: The impact of thyroid nodule size is less useful in children who have smaller thyroid volumes than in adults. We investigate using a novel thyroid tumor ratio measurement in children with thyroid cancer. METHODS: Patient and pathologic characteristics were investigated via Student's t-test in a univariate analysis for any correlation with the log-transformed tumor ratio, followed by a multivariate linear regression. RESULTS: Of 75 patients with malignancy and tumor ratio information, mean ratio decreased with increasing age (p = 0.04). Out of several clinical factors, patients with lymph node metastases and those treated with postoperative radioactive iodine had significantly higher mean tumor ratios on multivariate analysis (p = 0.04 for both factors). CONCLUSIONS: Our study is the first to describe thyroid tumor volume in pediatric thyroid cancer and shows that increased tumor ratio was associated with indicators of more advanced disease such as lymph node metastases and use of radioactive iodine.

Review of blast noise and the auditory system.

The auditory system is particularly vulnerable to blast injury due to the ear's role as a highly sensitive pressure transducer. Over the past several decades, studies have used a variety of animal models and experimental procedures to recreate blast-induced acoustic trauma. Given the developing nature of this field and our incomplete understanding of molecular mechanisms underlying blast-related auditory disturbances, an updated discussion about these studies is warranted. Here, we comprehensively review well-established blast-related auditory pathology including tympanic membrane perforation and hair cell loss. In addition, we discuss important mechanistic studies that aim to bridge gaps in our current understanding of the molecular and microstructural events underlying blast-induced cochlear, auditory nerve, brainstem, and central auditory system damage. Key findings from the recent literature include the association between endolymphatic hydrops and cochlear synaptic loss, blast-induced neuroinflammatory markers in the peripheral and central auditory system, and therapeutic approaches targeting biochemical markers of blast injury. We conclude that blast is an extreme form of noise exposure. Blast waves produce cochlear damage that appears similar to, but more extreme than, the standard noise exposure protocols used in auditory research. However, experimental variations in studies of blast-induced acoustic trauma make it challenging to compare and interpret data across studies.

Tracheostomy Outcomes in COVID-19 Patients in a Low Resource Setting.

OBJECTIVES: COVID-19 predominately affects safety net hospitals. Tracheostomies improve outcomes and decrease length of stay for COVID-19 patients. Our objectives are to determine if (1) COVID-19 tracheostomies have similar complication and mortality rates as non-COVID-19 tracheostomies and (2) to determine the effectiveness of our tracheostomy protocol at a safety net hospital. METHODS: Patients who underwent tracheostomy at Los Angeles County Hospital between August 2009 and August 2020 were included. Demographics, SARS-CoV-2 status, body mass index (BMI), Charlson Co-morbidity Index (CCI), length of intubation, complication rates, decannulation rates, and 30-day all-cause mortality versus tracheostomy related mortality rates were all collected. RESULTS: Thirty-eight patients with COVID-19 and 130 non-COVID-19 patients underwent tracheostomies. Both groups were predominately male with similar BMI and CCI, though the COVID-19 patients were more likely to be Hispanic and intubated for a longer time (P = .034 and P < .0001, respectively). Both groups also had similar, low intraoperative complications at 2% to 3% and comparable long-term post-operative complications. However, COVID-19 patients had more perioperative complications within 7 days of surgery (P < .01). Specifically, they were more likely to have perioperative bleeding at their tracheostomy sites (P = .03) and long-term post-operative mucus plugging (P < .01). However, both groups had similar 30-day mortality rates. There were no incidences of COVID-19 transmission to healthcare workers. CONCLUSIONS: COVID-19 tracheostomies are safe for patients and healthcare workers. Careful attention should be paid to suctioning to prevent mucus plugging. LEVEL OF EVIDENCE: 3.

Rate of Incidental Parathyroidectomy in a Pediatric Population.

OBJECTIVE: Incidental parathyroidectomy is a relatively common occurrence in thyroid surgery, which may lead to hypoparathyroidism and postoperative hypocalcemia, but it is not well studied in children. The objectives of this study were to determine the rate of incidental parathyroidectomy, identify potential risk factors, and investigate postoperative complications in children undergoing thyroidectomy. STUDY DESIGN: Retrospective cohort study. SETTING: Patients who underwent thyroidectomy over a 10-year period at a tertiary children's hospital. METHODS: Pathology reports were reviewed to determine incidental parathyroid gland tissue. Additional data collected included patient demographics, type of procedure, underlying thyroid pathology, as well as immediate and long-term postoperative clinical outcomes. RESULTS: Of 209 patients, 65 (31%) had incidental parathyroidectomy. Several variables were associated with incidental parathyroidectomy on univariable analysis. However, in the final multivariable model, only thyroidectomy with lymph node dissection was associated with increased odds of having incidental parathyroidectomy (odds ratio, 3.3; P = .04; 95% CI, 1.1-9.8). After a median follow up of 1 year, a significantly higher percentage of patients with incidental parathyroidectomy had evidence of long-term hypoparathyroidism (9/62 [15%] vs 3/144 [2%], P = .001). CONCLUSION: Incidental parathyroidectomy was relatively common in our pediatric thyroidectomy population, which may be a result of several anatomic, clinical, and surgeon-related factors. Close attention to parathyroid preservation with meticulous surgical technique is the most practical method of preventing long-term hypoparathyroidism and hypocalcemia.

Prevention of postsurgical lymphedema via immediate delivery of sustained-release 9-cis retinoic acid to the lymphedenectomy site.

BACKGROUND AND OBJECTIVES: Previously, we have shown that 9-cis retinoic acid (9-cis RA) stimulates lymphangiogenesis and limits postsurgical lymphedema in animal models when administered via daily intraperitoneal injections. In this study, we investigate whether a single-use depot 9-cis RA drug delivery system (DDS) implanted at the site of lymphatic injury can mitigate the development of lymphedema in a clinically relevant mouse limb model. METHODS: Hind limb lymphedema was induced via surgical lymphadenectomy and irradiation. Animals were divided into two treatment groups: (1) 9-cis RA DDS, (2) placebo DDS. Outcomes measured included paw thickness, lymphatic clearance and density, epidermal thickness, and collagen deposition. RESULTS: Compared with control animals, 9-cis RA-treated animals had significantly less paw swelling from postoperative week 3 (P = .04) until the final timepoint at week 6 (P = .0007). Moreover, 9-cis RA-treated animals had significantly faster lymphatic clearance (P < .05), increased lymphatic density (P = .04), reduced lymphatic vessel size (P = .02), reduced epidermal hyperplasia (P = .04), and reduced collagen staining (P = .10). CONCLUSIONS: Animals receiving 9-cis RA sustained-release implants at the time of surgery had improved lymphatic function and structure, indicating reduced lymphedema progression. Thus, we demonstrate that 9-cis RA contained within a single-use depot DDS has favorable properties in limiting pathologic responses to lymphatic injury and may be an effective strategy against secondary lymphedema.

A Pre-clinical Animal Model of Secondary Head and Neck Lymphedema.

Head and neck lymphedema (HNL) is a disfiguring disease affecting over 90% of patients treated for head and neck cancer. Animal models of lymphedema are used to test pharmacologic and microsurgical therapies; however, no animal model for HNL is described in the literature to date. In this study we describe the first reproducible rat model for HNL. Animals were subjected to two surgical protocols: (1) lymphadenectomy plus irradiation; and (2) sham surgery and no irradiation. Head and neck expansion was measured on post-operative days 15, 30 and 60. Magnetic resonance imaging (MRI) was acquired at the same time points. Lymphatic drainage was measured at day 60 via indocyanine green (ICG) lymphography, after which animals were sacrificed for histological analysis. Postsurgical lymphedema was observed 100% of the time. Compared to sham-operated animals, lymphadenectomy animals experienced significantly more head and neck swelling at all timepoints (P < 0.01). Lymphadenectomy animals had significantly slower lymphatic drainage for 6 days post-ICG injection (P < 0.05). Histological analysis of lymphadenectomy animals revealed 83% greater subcutis thickness (P = 0.008), 22% greater collagen deposition (P = 0.001), 110% greater TGFß1+ cell density (P = 0.04), 1.7-fold increase in TGFß1 mRNA expression (P = 0.03), and 114% greater T-cell infiltration (P = 0.005) compared to sham-operated animals. In conclusion, animals subjected to complete lymph node dissection and irradiation developed changes consistent with human clinical postsurgical HNL. This was evidenced by significant increase in all head and neck measurements, slower lymphatic drainage, subcutaneous tissue expansion, increased fibrosis, and increased inflammation compared to sham-operated animals.