Training and competence perception differences in otolaryngology and head and neck surgery training program - an anonymous electronic national survey.

BACKGROUND: Otorhinolaryngology / Head and Neck Surgery consists of different sub-specialties, each comprising unique characteristics and challenges. Herein, we investigate the use of a uniform national electronic questionnaire for curriculum planning. MAIN OUTCOME MEASURES: (1) Analyze the residents' perception of the different sub-specialties training programs and their competence capabilities. (2) Identify sub-specialties requiring attention. (3) Investigate the characteristics associated with competence perception. METHODS: This is a national cross sectional study. An anonymous electronic questionnaire was emailed to all registered Otorhinolaryngology / Head and Neck Surgery residents. RESULTS: 63.5% registered residents responded to the questionnaire. Two sub-specialties, Rhinology and Laryngology, are located in the extremities of the residents' perceptions of competence and training (p < 0.0001), despite similar complexity perception (means 6.10 and 6.01, respectively). Rhinology is perceived as the most well-trained sub-specialty, both surgically and clinically (means 7.08 and 7.66, respectively), whereas Laryngology is bottom scaled (means 5.16 and 6.14, respectively). The same is true for perceived competence, surgical and clinical, in Rhinology (means 6.80 and 8.02, respectively) compared to Laryngology (means 5.04 and 6.75, respectively). Significant positive correlations were found between training, competence perception and workload ("golden training triangle"). CONCLUSIONS: Each ORL-HNS sub-specialty comprises different characteristics and a different learning curve, necessitating a tailored training program. Recognizing its sub-specialties distinctive features may assist in establishment of better-adapted learning curves in residency programs. Herein, we examine the use of anonymous electronic national survey. Laryngology, bottom ranked, is a prototype of a relatively new surgical discipline. Rhinology, ranked top by the residents, is an exemplar of a sub-specialty with an optimal 'educational environment'. Moreover, we have established golden training triangle, implicating, highlights the essential role of institutional and senior staff for proper residency teaching. We demonstrate and advocate the benefit of using an anonymous electronic questionnaire.

Bilateral Intratonsillar Abscesses: A Deceiving Symmetrical Oral Bulging.

BACKGROUND: Unilateral intratonsillar abscess (ITA) is an underreported, well-known complication of acute tonsillitis. The prevalence of unilateral ITA compared to peritonsillar abscess (PTA) is 1:14. However, bilateral ITA is an extremely rare entity, with only four cases reported thus far. OBJECTIVES: To describe past cases and our experience, elaborating the diagnostic challenge and the surgical treatment for bilateral ITA. METHODS: We conducted a literature search in the PubMed database using the key words intra-tonsillar abscess, tonsillar abscess, bilateral tonsillar abscess, bilateral intra-tonsillar abscess and bilateral peritonsillar abscess. Our search was limited to the years 1980 to 2020. RESULTS: We found that only four cases of bilateral ITA were previously published. All were characterized by a delay in diagnosis with a median of 10 days (4-14 days), symmetrical oral cavity appearance, enlarged bilateral kissing tonsils, and subsequent treatment by surgical drainage/paracentesis. Respiratory compromise was a concern in most cases. Our patient was treated with bilateral quinsy tonsillectomy and had a prompt recovery. CONCLUSIONS: Bilateral ITA is a rare, deceiving entity, with a diagnosis delay attributed to the symmetrical oral bulging. We present the fifth case reported and the first ever reported in a pediatric patient. We describe the assumed pathogenesis and the main characteristics among all five patients, emphasizing the important role of a high index of suspicion and appropriate imaging, guiding to proper diagnosis and treatment.

Double trouble: A cohort study of re-irradiation and laryngectomy - Severity of and risk for pharyngocutaneous fistula.

OBJECTIVES: Pharyngocutaneous fistula (PCF) is a devastating complication of laryngectomy. Different factors, principally previous irradiation, increases the risk for PCF formation. The current study objectives is to investigate the potential negative effect of re-irradiation on fistula development. Materilas and methods This is a single, referral, medical center retrospective, cohort study, conducted between the years 2011-2021. Electronic medical files, surgical notes, laboratory records and radiation plan (dose and time interval in case of re-irradiation) were examined. Main outcomes and measures Risk and predictors associated with PCF formation. Risk and severity of PCF in the setting of re-irradiation. RESULTS: Overall, 27 laryngectomized patients were investigated, of whom 21 patients had single radiation (pre or post-operative radiation) and the other 6 patients had two radiation treatments (before and after laryngectomy). The fistula rate was 33.33% (7/21) in the single radiation compared (p = 0.14) to 66.66% (4/6) in the re-irradiation group of patients (including late-onset fistulas). All single radiation PCF were self-limited, whereas, 3 out of 4 fistulas in the re-irradiation group were longstanding or permanent. In the re-irradiation group of patients, a shorter time interval between the first and second radiation treatments was demonstrated among those with fistula formation compared to patients with uneventful laryngectomy (p = 0.08). CONCLUSION: Re-irradiation and especially a brief interval between the radiation treatments is associated with a severe PCF.

A Cohort Study of the Surgical Risks and Prediction of Complications in Surgical Tracheostomies.

BACKGROUND: Current protocols favor percutaneous tracheostomies over open procedures. We analyzed the effects of this conversion from the open approach to the percutaneous procedure in terms of relevant clinical status, complications, and mortality in surgical open tracheostomies. Relevant laboratory and clinical parameters, potentially associated with complications, were also examined. MAIN OUTCOME MEASURES: Comparison of clinical, laboratory data and outcome of surgical tracheostomy during the two eras. Investigate potential pertinent predictive parameters associated with complications. METHODS: A single center retrospective case series of consecutive patients who underwent surgical tracheostomy between the years 2006-2009 ("early era") and 2016-2020 ("late era"). RESULTS: The study included 304 patients, 160 in the "early" and 144 in the "late" era. Despite a 78% increase in patient volume in the intensive care units, there was a 55% decrease in surgical tracheostomy during the "late era". Significantly more patients with structural deformities (p < 0.001), insulin dependent diabetes mellitus (p = 0.004), extreme (high and low) body weight (p = 0.006), anemia (p < 0.001) and coagulation disorders (p < 0.001), were referred for an open tracheostomy during the "late era". The complication rate was significantly higher during the "late era" (11.7 vs. 2.5%, OR 6.09 CI 95% [1.91-19.39], p = 0.001). Diabetes mellitus (p = 0.005), anemia (p = 0.033), malnutrition (p = 0.017), thrombocytopenia (p = 0.002) and poor renal function, (p = 0.008), were all significantly associated with higher complication rates. CONCLUSIONS: Risk assessment and training programs must reflect the decrease in surgical volume of open tracheostomies and consequently reduced experience. The increase of a patient subset characterized by pertinent comorbidities should reflect this change.

Minimally Invasive Parathyroidectomy: Can Intraoperative Parathyroid Hormone Monitoring be Omitted?

BACKGROUND: Intraoperative PTH (ioPTH) monitoring has become widely accepted in the era of minimally invasive parathyroidectomy (MIP). The purpose of this study was to evaluate the need for ioPTH during parathyroidectomy in patients with positive preoperative imaging. METHODS: The charts of patients who underwent parathyroidectomy at three tertiary centers between the years 2012 and 2021 were retrospectively reviewed. Patients were defined as MIP candidates with either concordant preoperative imaging or a single positive imaging. Patients with negative or discordant imaging, concomitant thyroidectomy, or previous neck surgery were excluded. RESULTS: Of a total of 1013 patients who underwent parathyroidectomy, 535 (52.8%) were defined as MIP candidates and were included in the statistical analysis. Surgical success was achieved in all patients. A single adenoma that corresponded to the preoperative imaging was identified and resected in 517 (93.8%) patients. In only 18 (3.3%) patients, the ioPTH correctly changed the operative management where additional pathologic glands were identified and excised. Patients with additional lesions were significantly more likely to have decreased index adenoma size as indicated either by preoperative imaging or by intraoperative findings (15.5 ± 6.6 vs. 8.3 ± 2.5 mm, p < 0.001). None of the patients with an adenoma size greater than 13 mm had an additional pathologic gland. CONCLUSIONS: Our findings suggest that the routine use of ioPTH in MIP candidates may be omitted in patients with an index adenoma greater than 13 mm, even with only a single positive preoperative imaging study, without compromising surgical success.

Sentinel Lymph Node Identification in Cutaneous Head & Neck Cancer - Lymphoscintigraphy Late Phase.

OBJECTIVE: Sentinel node (SN) biopsy following lymphoscintography is recommended for high-risk cutaneous malignancies. Herein, we investigate different lymphoscintography phases, focusing on the importance of the late static phase and the resultant discovery of distal echelon solitary positive sentinel nodes that would otherwise have been overlooked. METHODS: In this retrospective cohort study, conducted in a tertiary referral medical center, we assessed SN localization and time from tracer injection to SN identification on lymphoscintigraphy. Findings on scan were compared with SN found in the surgical field, and with the final pathological investigation. RESULTS: Seventy-three patients, undergoing SN biopsy for head and neck skin malignancies, were investigated. Most patients were male (n = 50). The average age was 65.7 (±15.7) years and the average follow-up time was 29.1 (±22.4) months. Overall, 101 SNs were histologically investigated, demonstrating 7 positive SN. Eleven patients (15%) benefited from the late lymphoscintigraphy phase. In four studies, an SN was identified only in the late static phase, one of which was positive for the disease. In seven patients, SN was identified in the early phase with additional, different, SN on the late phase, one of which was positive for the disease. Comparing the yield (positive SNs) of early versus late phases, demonstrated the same importance (p = 0.275). CONCLUSIONS: The late lymphoscintigraphy phase has a crucial role in high-risk HN cutaneous cancer. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:2164-2168, 2022.

Modified bi-weekly cetuximab-cisplatin and 5-FU/leucovorin based regimen for effective treatment of recurrent/metastatic head and neck squamous cell carcinoma to reduce chemotherapy exposure of patients.

BACKGROUND: The standard chemotherapy treatment protocol for patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) requires as long as 56 days of hospitalization over six months. Where the 5-Fluorouracil (5-FU) pump is available, most treatment will be on outpatient bases, however patients will still be under chemotherapy treatment for a comparable period of time (around 50 days). AIM: A modified protocol was assessed to decrease hospitalization and/or chemotherapy treatment time without sacrificing outcomes, to potentially increase patient quality of life. METHODS AND RESULTS: A retrospective analysis (2005-2018) of recurrent/metastatic HNSCC patients with a modified treatment protocol was performed. Treatment consisted of cisplatin, cetuximab, 5-fluorouracil bolus and leucovorin administered on day 1 of a 2-week cycle, and a continuous infusion of 5-fluorouracil on days 1-2 of the cycle. Outcomes were measured by progression-free survival, overall survival, and patient hospitalization time. Analysis was done using the Kaplan-Meier survival function curve. The study cohort consisted of 27 patients. The modified treatment protocol resulted in a median progression-free survival of nine months and median overall survival of 14 months, while hospitalization time was reduced by almost 80% in the first six months of treatment. CONCLUSIONS: Modification of the cisplatin, cetuximab, 5-FU and leucovorin protocol to a bi-weekly regimen utilizing alternative drug delivery methods, significantly reduced patient hospitalization from 56 days to 12 days in the first 6 months of treatment. This was achieved without compromising treatment outcome, while significantly reducing the days patients were exposed to chemotherapy, and thus potentially improving quality of life.

Salivary Gland Heterotopia, a Clinical and Pathological TNM Staging Challenge - Carcinoma ex Pleomorphic Adenoma Arising in a Parotid Lymph node.

INTRODUCTION: Heterotopia is the presence of a particular tissue / tumor at a non-physiological / ectopic site. The study primary goals: To review the current data investigating heterotopic, normal appearing, and diseased salivary gland tumors, in lymph nodes. To describe the meticulous pathological investigation and multidisciplinary decision-making process of a heterotopic carcinoma ex pleomorphic adenoma arising in an intra-parotid lymph node. MATERIALS AND METHODS: A literature search in the "PubMed" database using key words "carcinoma ex pleomorphic adenoma", "parotid lymph node", "salivary gland" and "heterotopia" was conducted. We describe the thorough pathological investigation and clinical decision-making process, focusing TNM staging system limitations. RESULTS: A few case reports presented either normal appearing salivary tissue, benign tumors or low and high-grade salivary malignancies arising in lymph nodes. We present the investigation, controversies and treatment decision process of a 46-year-old man with CXPA in intra-parotid lymph node. CONCLUSIONS: The staging scheme does not distinguish between nodal spread and primary tumor arising in a lymph node. Multidisciplinary input regarding prognosis and follow-up plans, may consider heterotopia differently from the usual pattern of nodal spread.

Spatial Intratumoral Heterogeneity Expression of PD-L1 Antigen in Head and Neck Squamous Cell Carcinoma.

INTRODUCTION: Immune-checkpoint inhibitors have demonstrated a significant survival benefit in metastatic and non-resectable head and neck squamous cell carcinoma (HNSCC). Patients with a combined positivity score (CPS) of 20 and higher benefit the most from therapy. Inaccurate definition of the CPS category might lead to the incorrect stratification of patients to immunotherapy. This study's main aim was to investigate programmed death-ligand 1 (PD-L1) antigen expression in HNSCC in diverse clinical situations and histological settings. MATERIALS AND METHODS: This is a prospective cohort study conducted in a tertiary referral medical center. Tissues were investigated for PD-L1 expression using the FDA-approved 22C3 immunohistochemistry assay (Dako). We analyzed potential associations between the CPS category and meaningful demographic, clinical, and outcome metrics. Furthermore, we investigated morphologically separate sites for CPS scores in whole surgical tissue specimens and matched preoperative biopsies. RESULTS: We analyzed 36 patients, of whom 26 had oral cavity SCC and 10 had laryngeal SCC. The overall, disease-specific, and progression-free survival of the HNSCC group of patients were not associated with the CPS category (p = 0.45, p = 0.31, and p = 0.88, respectively). There was a significant (18%, 95% CI 0.65-0.9) inconsistency between the CPS category determined in biopsies versus whole carcinoma analyses. We also found an uneven distribution of whole-tumor CPS attributed to spatial carcinoma invasiveness, tumor differentiation, and inflammatory cell infiltration heterogeneity. DISCUSSION AND CONCLUSIONS: Our data suggest that careful selection of tumor area for CPS analysis is important. PD-L1 antigen expression, clinically represented by CPS, may be up- or down-categorized in different clinical and pathological circumstances. The high whole-tissue CPS category scatter may clinically result in potential treatment modifications. We argue that CPS analysis requires not only adequacy (at least 100 viable tumor cells), but also correct representation of the tumor microenvironment.

Checkpoint inhibitors: Better outcomes among advanced cutaneous head and neck melanoma patients.

OBJECTIVE: The aim of this study was to investigate if the treatment outcomes of checkpoint inhibitors (CPI) in patients with advanced-stage skin head and neck melanoma (HNM) differs from outcomes in patients with non-HNM. DESIGN: A retrospective cohort study of patients with unresectable AJCC stage III and stage IV, who received CPI between 2010 and 2017. PARTICIPANTS: Overall, 122 unresectable AJCC stage III and metastatic stage IV melanoma adult patients were treated with CPI during the study period (consecutive patients). The HNM group of patients was comparable with limbs and trunk melanoma group except different distant metastatic (M1a/b/c/d) pattern (p = 0.025). MAIN OUTCOMES: Comparison of overall survival and clinical response to CPI in patients with advanced-stage skin melanoma of the head and neck with non-HNM. RESULTS: We analyzed 38 patients with melanoma arising in the head and neck skin regions, 33 with melanoma of limbs and 51 with trunk melanoma. Most of the head and neck patients were men (89.5%), the average age of melanoma diagnosis was 61.4±16.7 years (range 16.4-85.6). More than a third of HNM group of patients (36.8%) were 70 years and older. Overall response rate (ORR) to CPI was 50% (CR 31.6% and PR 18.4%) in the head and neck study group of patients, compared to an ORR of 36.3% and 23.5% in melanoma of the limbs and of the trunk, respectively (p = 0.03). The median overall survival of HNM group of patients was 60.2±6.3 months, CI 95% [47.7-72.7], 63% were alive at 30 months, reaching a plateau. Whereas, the median survival time of limbs and trunk melanoma were 51.2 and 53.4 months, which did not reach significance. CONCLUSIONS AND RELEVANCE: Response rate to CPI is significantly improved in patients with melanoma of the head and neck and they have a trend towards improved, long standing, overall survival.

[HEAD AND NECK MALIGNANCIES CLASSIFICATION, THE 8TH EDITION OF THE AMERICAN JOINT COMMITTEE ON CANCER - WHAT IS NEW?]

INTRODUCTION: The American Joint Committee on Cancer (AJCC) staging manual has become the point of reference for classifying patients with cancer, defining prognosis, and determining the best treatment approaches. The eighth edition of the Head and Neck AJCC Cancer Staging Manual incorporates significant changes based on advances in our understanding of the etiology and certain histologic attributes of tumors. Changes were made only when there was strong evidence for inclusion, while balancing between "population-based" and a more "personalized" approach. We describe the main changes implanted into the AJCC 8th edition while analyzing the effects on treatment plans and survival metrics. 1. The most significant update, to better reflect the variety of diseases arising in the pharynx, creates a separate staging algorithm for high-risk human papillomavirus-associated cancer of the oropharynx. Therefore, pharynx carcinoma has been divided into 3 separate chapters - nasopharynx, high-risk HPV-associated (p16-positive) oropharynx, and hypopharynx and non-high risk HPV-associated (p16-negative) oropharynx. 2. Another important update incorporates extra nodal extension as a prognostic variable for regional lymph node metastases in non-viral associated head and neck tumors. 3. Significant changes to the tumor (T) categories for oral cavity are discussed, where, for every 5-mm increase in depth of invasion (DOI), categories will increase one level, demonstrating better consistent and predictive survival curves. 4. A major tumor (T) category change for nasopharyngeal squamous cell carcinoma (SCC), regarding the prevertebral and pterygoid muscles, is discussed. We go through the rationale behind the major changes while practicing the new staging system among different cases.

The Microbiology Characteristics of Infected Branchial Cleft Anomalies.

OBJECTIVES: To investigate the microbiology profile of infected branchial cleft anomalies compared to deep neck infection and explore the influence of age on culture findings. STUDY DESIGN: A retrospective case control study. SETTING: A single tertiary medical center. SUBJECTS AND METHODS: Patients treated for branchial cleft anomalies between 2006 and 2016 were included. Demographic data, disease and treatment parameters, and microbiology profile, including bacteria classification, antibiotics resistance patterns, and number of pathogens, were analyzed. RESULTS: Of 278 cases treated for branchial cleft anomalies, we have analyzed 69 cases with infection and pathogen identification. The proportion of monobacterial infections was higher (70.6% vs 44.3%; P = .003; odds ratio [OR], 3.02) and the proportion of Streptococcus species infection was lower (48.9% vs 77.2%; P = .001; OR, 0.282) among the infected branchial cleft cases compared to deep neck infections. Anaerobic bacteria infection did not differ between groups (17.8% and 16.5%, respectively). There was a nonsignificant tendency toward more resistant bacterial strains among the infected branchial clefts (15.6% vs 6.3%; P = .118; OR, 2.726). There was no difference between the bacterial profile of patients younger or older than 16 years. CONCLUSIONS: The microbiology profile of infected branchial cleft anomalies is not age related and is different from that of deep neck infections. We demonstrate a relatively high frequency of monobacterial infections, relatively lower streptococcal infection rates, and a substantial contribution by resistant species and anaerobes. Empiric antibiotic treatment should cover Streptococcus species, including penicillin-resistant species, as well as clindamycin-resistant anaerobes.

Thyroidectomy Practice After Implementation of the 2015 American Thyroid Association Guidelines on Surgical Options for Patients With Well-Differentiated Thyroid Carcinoma.

IMPORTANCE: The recommended extent of surgery for well-differentiated thyroid carcinoma has been modified considerably in the updated 2015 American Thyroid Association guidelines published in January 2016. To date, the changes in clinical practice after publication of these new guidelines have not been demonstrated. OBJECTIVE: The aim of this study was to evaluate clinical practice changes associated with implementation of the updated guidelines on the surgical procedure rates of total thyroidectomy, thyroid lobectomy, and completion thyroidectomy at a single tertiary medical center. DESIGN, SETTING, AND PARTICIPANTS: This is a retrospective cohort study of 169 patients at the Hadassah-Hebrew University Medical Center, Jerusalem, Israel. Patients with pathologically proved, well-differentiated thyroid carcinoma who underwent surgery between January 1, 2013, and December 31, 2014, were compared with patients who underwent surgery from January 1 to December 31, 2016. A total of 434 thyroidectomy procedures were performed during the study period, and 251 had pathologically proved, well-differentiated thyroid carcinoma. Patients with tumors larger than 4 cm, involved lymph nodes, or bilateral nodules were excluded. MAIN OUTCOMES AND MEASURES: Primary outcomes were the rate of up-front total thyroidectomy vs lobectomy and the rates of completion thyroidectomy before and after the implementation of the new guidelines. RESULTS: Of the 169 patients in the final analysis, 118 (69.8%) were included from 2013 to 2014 and 51 (30.2%) in 2016. The mean (SD) age for the entire cohort was 44 (13.8) years, and 129 (76.3%) were women. Up-front total thyroidectomy was performed in 72 of 118 patients (61.0%) prior to the 2015 American Thyroid Association guidelines and 16 of 51 (31.4%) following their implementation (odds ratio, 0.29; 95% CI, 0.14-0.59). The rate of completion thyroidectomy also significantly decreased between these periods (73.9% vs 20.0%; odds ratio, 0.09; 95% CI, 0.04-0.19). CONCLUSIONS AND RELEVANCE: The updated 2015 American Thyroid Association guidelines implementation was associated with a significant decrease in the rates of both up-front total thyroidectomy and completion thyroidectomy. According to these findings, only 1 of 5 patients who undergoes thyroid lobectomy will require a completion procedure.

Otolaryngology/head and neck region manifestations of Brucella.

OBJECTIVES/HYPOTHESIS: Patients with Brucella infection present with nonspecific symptoms originating from different organs. In this study, we investigated the manifestations involving principally the otolaryngology/head and neck region. STUDY DESIGN: Retrospective cohort chart review. METHODS: A retrospective analysis of patients diagnosed with brucellosis in a tertiary medical center. Medical records of 55 patients treated for positive Brucella blood cultures between 2007 and 2016 were analyzed. Clinical manifestations localized to the otolaryngology/head and neck region were evaluated. RESULTS: Most patients (78%) in our study group lived in rural areas. There was an almost equal gender distribution and a wide age range (2-77 years). Nonspecific symptoms, including fever (71%), fatigue (31%), weight loss (20%), and night sweats (32.7%) were the most common. Of the specific organ systems affected by Brucella, the osteoarthritic system was most commonly infected (45.5%). Three patients (5.5%) presented with predominantly localized otolaryngology/head and neck region symptoms, consisting of necrotic lymphadenopathy or a thyroid abscess. All patients underwent drainage procedures, and the diagnosis was confirmed by positive blood and pus cultures. Complete resolution was achieved with prolonged antibiotic treatment. CONCLUSIONS: Brucella infection should be suspected in patients with nonspecific constitutional symptoms associated with neck lymphadenopathy or thyroid abscess, especially in those living in rural areas. A high index of suspicion is mandatory for proper diagnosis and treatment. Formal drainage and prolonged antibiotic treatments are required. We strongly recommend simple drainage and not excision as the mainstay of surgical treatment. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:2056-2059, 2018.

Extraction of a headscarf pin from the vertebral artery without embolization.

BACKGROUND: Foreign bodies traversing the aerodigestive tract lining into the surrounding soft tissues is a well-known entity. A 14-year-old girl was referred to our hospital after swallowing a pin that was not visualized by laryngoscopy, despite a neck film that localized it to the level of the larynx. METHODS: A CT scan demonstrated a bent pin piercing the left vertebral artery "through and through," and this was confirmed by angiography. The pin was extracted via an external approach to the neck without preoperative intravascular manipulation. RESULTS: Angiography immediately after the surgery demonstrated a stable thrombotic sleeve in the vertebral artery without further clot propagation or bleeding from the vessel wall. This is the first report of a "through and through" thrombotic sleeve in an artery. CONCLUSIONS: Simple surgical removal of a sharp foreign body from the vertebral artery without intravascular management may be a reasonable option.

Effects of furosemide on the hearing loss induced by impulse noise.

BACKGROUND: The permanent hearing loss following exposure to intense noise can be due either to mechanical structural damage (tearing) caused directly by the noise or to metabolic (biochemical) damage resulting from the elevated levels of free radicals released during transduction of the sound overstimulation. Drugs which depress active cochlear mechanics (e.g. furosemide and salicylic acid) or anti-oxidants (which counteract the free radicals) are effective in reducing the threshold shift (TS) following broadband continuous noise. This study was designed to determine whether furosemide can reduce the TS following exposure to impulse noise, similar to its action with continuous broadband noise. METHODS: Shortly after furosemide injection, mice were exposed to simulated M16 rifle impulse noise produced by different loudspeakers and amplifiers in different exposure settings and, in other experiments, also to actual M16 rifle shots. RESULTS: Depending on the paradigm, the simulated noises either did not produce a TS, or the TS was reduced by furosemide. The drug was not effective in reducing TS resulting from actual impulse noise. CONCLUSION: Simulated M16 rifle impulse noise may not truly replicate the rapid rise time and very high intensity of actual rifle shots so that the TS following exposure to such noise can be reduced by these drugs. On the other hand, actual M16 impulse noise probably causes direct (frank) mechanical damage, which is not reduced by these drugs.