[Auditory brainstem implantation: current status and prospects]

Auditory brainstem implantation is a hearing restoration technique on the central auditory pathway, which directly stimulates neural tissues of cochlear nucleus by electrode array to produce hearing, so it will not be restricted by abnormalities of the cochlea and cochlear nerve. In the past 30 years since the birth of multi-channel ABI, its indications have expanded from patients with neurofibromatosis type 2 (NF2) to congenital deafness patients with severe inner ear and/or cochlear nerve malformations, and the age of recipients decreases from adults to young children. This article summarizes the principle, indications, surgical techniques, complications and auditory outcomes of ABI.

Impact of macrophage infiltration in patients with st-segment elevation myocardial infarction caused by plaque erosion: an in vivo optical coherence tomography study

Background

Chronic inflammatory infiltration is a common process for atherosclerosis development. However, autopsy studies reveal that incidence rate of inflammatory infiltrates are less abundant in plaque erosion compared with plaque rupture.

Purpose

Studies performed by optical coherence tomography (OCT) have allowed to establish the severity of plaque inflammation by assessing macrophage infiltration (MØI). In this study, we aimed at assessing the impaction of MØI in plaque erosion among patients with STEMI by using OCT.

Methods

A total of 1561 patients with ST-segment elevation myocardial infarctions (STEMI) who underwent OCT imaging were enrolled in this study. According to the exclusion criteria, 312 patients with STEMI exhibiting plaque erosion were classified as MØI or no MØI.

Results

163 (52.2%) patients had MØI at the site of plaque erosion, whereas 149 (47.8%) patients had no evidence of MØI and patients of MØI group were significantly older (P=0.015). The result of angiography showed the prevalence of multi-vessel disease appeared more frequency (P=0.021) and diameter stenosis% were higher (P=0.031) in MØI group. OCT results showed the minimum fibrous-cap thickness was thinner (P<0.001) and the maximum lipid arc was larger (P=0.005) in MØI group. Some patients underwent imaging follow-up at 1 year. There was no significant difference in the culprit plaque morphology progress among two groups (Figure 1A-1D).

Conclusions

This study demonstrated that plaque inflammation can increase culprit lesion severity and plaque vulnerability in patients with STEMI caused by plaque erosion.

Figure 1

Funding Acknowledgement

Type of funding source: None

The probiotic Lactobacillus casei Shirota attenuates symptoms of vestibular migraine: a randomised placebo-controlled double-blind clinical trial

Vestibular migraine (VM) has emerged as one of the major vestibular syndromes. Although probiotics have exhibited beneficial effects on migraine headache, its effect on VM is not clear. This trial aimed to investigate the treatment efficacy of the probiotic Lactobacillus casei Shirota (LcS) on symptoms of VM. 247 VM patients were enrolled, of which 204 eligible patients receiving either LcS or placebo on a daily basis completed the 4 month study. They were re-visited at 2 and 4 months after study initiation to assess treatment outcomes. The primary endpoints were vestibular symptoms, evaluated by the number of vertiginous attacks during the past week, the Vertigo Severity Score (VSS), and Dizziness Handicap Inventory (DHI) scores. The secondary endpoints were anxiety and depressive symptoms, evaluated using Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) scores. Efficacy of LcS over placebo was not obvious at 2 month follow-up. At 4 month follow-up, while both LcS and placebo groups of VM patients displayed alleviated symptoms, the extents of the improvements were significantly better in LcS group than those of placebo group, with regard to vestibular symptoms using DHI and VSS, as well as anxiety and depressive symptoms using BAI and BDI. Although placebo effect cannot be ignored in intervention for VM patients, the probiotic LcS still exhibits considerable efficacy against VM symptoms over a 4 month study period, supporting further clinical study of a larger and more diverse cohort.

Isolation and sequence analysis of the complete VP2 gene of canine parvovirus from Chinese domestic pets and determination of the pathogenesis of these circulating strains in beagles

Canine parvovirus (CPV) causes acute gastroenteritis in domestic dogs, cats, and several wild carnivore species. In this study, the full-length VP2 gene of 36 CPV isolates from dogs and cats infected between 2016 and 2017 in Beijing was sequenced and analyzed. The results showed that, in dogs, the new CPV-2a strain was the predominant variant (n = 18; 50%), followed by the new CPV-2b (n = 6; 16.7%) and CPV-2c (n = 3; 8.3%) strains, whereas, among cats, the predominant strain was still CPV-2 (n = 9; 25%). One new CPV-2a strain, 20170320-BJ-11, and two CPV-2c strains, 20160810-BJ-81 and 20170322-BJ-26, were isolated and used to perform experimental infections. Multiple organs of beagles that died tested PCR positive for CPV, and characteristic histopathological lesions were observed in organs, including the liver, spleen, lungs, kidneys, small intestines, and lymph nodes. Experimental infections showed that the isolates from the epidemic caused high morbidity in beagles, indicating their virulence in animals and suggesting the need to further monitor evolution of CPV in China.

pUC18-CpG stimulates RAW 264.7 via TBK1-mediated pathway and presents adjuvanticity in mice

Phosphorothioate CpG oligodeoxynucleotides (ODN) are reported to be recognized by the membrane-bound TLR9 and trigger the MyD88-dependent up-regulation of Type I interferons and pro-inflammatory cytokines. Whether plasmids containing multiple CpG motifs stimulate the same signaling pathway is yet to be determined. The present results show that the CpG motifs enrich plasmid pUC18-CpG stimulates RAW 264.7 in vitro, mainly through the TBK1-mediated signaling pathway, causing the up-regulation of IFN-β, and pro-inflammatory cytokines TNF-α and IL-6. When pUC18-CpG is co-administered with the recombinant Echinococcus granulosus antigen, the antigen-specific antibody titers are markedly increased compared to the Quil-A adju- vanted group. Antigen specific cytokine quantification shows that cytokine profiles from the pUC18-CpG adjuvanted-group are switched to a Th1-biased immune response.

Surgery of the lateral skull base: a 50-year endeavour

Disregarding the widely used division of skull base into anterior and lateral, since the skull base should be conceived as a single anatomic structure, it was to our convenience to group all those approaches that run from the antero-lateral, pure lateral and postero-lateral side of the skull base as “Surgery of the lateral skull base”. “50 years of endeavour” points to the great effort which has been made over the last decades, when more and more difficult surgeries were performed by reducing morbidity. The principle of lateral skull base surgery, “remove skull base bone to approach the base itself and the adjacent sites of the endo-esocranium”, was then combined with function preservation and with tailoring surgery to the pathology. The concept that histology dictates the extent of resection, balancing the intrinsic morbidity of each approach was the object of the first section of the present report. The main surgical approaches were described in the second section and were conceived not as a step-by-step description of technique, but as the highlighthening of the surgical principles. The third section was centered on open issues related to the tumor and its treatment. The topic of vestibular schwannoma was investigated with the current debate on observation, hearing preservation surgery, hearing rehabilitation, radiotherapy and the recent efforts to detect biological markers able to predict tumor growth. Jugular foramen paragangliomas were treated in the frame of radical or partial surgery, radiotherapy, partial “tailored” surgery and observation. Surgery on meningioma was debated from the point of view of the neurosurgeon and of the otologist. Endolymphatic sac tumors and malignant tumors of the external auditory canal were also treated, as well as chordomas, chondrosarcomas and petrous bone cholesteatomas. Finally, the fourth section focused on free-choice topics which were assigned to aknowledged experts. The aim of this work was attempting to report the state of the art of the lateral skull base surgery after 50 years of hard work and, above all, to raise questions on those issues which still need an answer, as to allow progress in knowledge through sharing of various experiences. At the end of the reading, if more doubts remain rather than certainties, the aim of this work will probably be achieved.

Genotyping and pathogenic characterization of canine distemper virus based on mutations in the hemagglutinin gene in Chinese domestic dogs

Canine distemper virus (CDV) infects wild and domestic Canidae worldwide. The hemag- glutinin (H) gene has the highest genetic variation in the genome of this virus. Thus, the H gene is commonly used for lineage identification and genetic analyses. In order to study the genetic characteristics and pathogenicity of CDV strains prevalent in China, 132 samples were collected from domestic dogs with suspected CDV infection, 58 samples were confirmed to be positive, and the H gene was successfully amplified from 15 samples. The epidemic strain was identified as type Asia-1 and the novel mutations, A51T, V58I, R179K and D262N, were detected in this strain. Isolated strains, BJ16B53, BJ16B14, and BJ17B8, were used for an animal infection experiment in raccoon dogs. BJ16B53 and BJ16B14 were found to cause clinical symptoms, death, and exten- sive lesions in various organs. These results are expected to facilitate the development of effective strategies to monitor and control CDV infection in China.

P3390Relationship of thrombus healing to underlying plaque characteristics in ST-segment elevation myocardial infarction: an optical coherence tomography study

Background

Acute ST-segment elevation myocardial infarction (STEMI) is typically characterized by an occlusive coronary thrombus propagation on a disrupted or eroded atherosclerotic plaque. A variable period of plaque instability and thrombus formation occur days or weeks old in approximately 50% of patients with STEMI. Presence of late stage (older) thrombi in aspirated coronary material is an independent predictor of 1-year and long-term mortality in STEMI patients. However, the relationship between coronary thrombus healing to underlying plaque morphology and characteristics in vivo still remains largely unknown.

Purpose

Our objective was to assess differences in thrombus healing between ruptured and eroded plaques in vivo and evaluate the impact of underlying plaque characteristics on thrombus healing using optical coherence tomography (OCT).

Methods

Analyzable coronary material was obtained during primary percutaneous coronary intervention (PCI) from 135 patients with STEMI within 12h of symptom onset. Thrombi were morphologically classified as either early or late stage (lytic changes or organization). Of the 135 patients, 110 were eligible for culprit lesion evaluation using OCT. Quantitative and qualitative underlying plaque characteristics were assessed by OCT.

Results

Late-stage thrombi were found in 49 of 110 (44.5%) culprit plaques. Patients with eroded plaques more frequently had late-stage thrombi compared with ruptured plaques (59.0% vs. 36.6%, p<0.001). Subgroup analysis was performed between plaque rupture, identified in 71 patients (64.5%) and plaque erosion in 39 patients (35.5%). In plaque ruptures, patients with late-stage thrombi had larger lipid core length (12.4±3.3 vs. 14.5±3.8, p=0.020), larger rupture cavity length [1.5 (1.0, 2.0) vs. 1.9 (1.5, 2.8), p=0.034] and increased residual thrombus length [7.8 (6.3, 11.2) vs. 10.3 (7.8, 13.8), p=0.021] assessed by OCT compared with early thrombus group. However, in plaque erosions, late stage thrombi were associated with decreased residual thrombus burden compared with patients with early thrombus group [16.8 (12.8, 20.4) vs. 13.4 (10.7, 14.8), p=0.012]. No significant difference was found between thrombus healing with peak creatine kinase concentration or maximum NT-pro BNP in subgroup analysis.

Conclusions

Coronary thrombi in STEMI patients exhibited diverse phases of healing, depending on the etiology of the underlying culprit plaque in vivo. These observations indicate entirely distinct mechanisms of thrombus propagation, maturation and healing between plaque rupture and erosion, illustrating an opportunity for more tailored treatment in patients with different plaque type.

Phospholipase C signaling is involved in porcine reproductive and respiratory syndrome virus infection in cell cultures

The phospholipase C (PLC) is a family of kinases that hydrolyze phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] to generate two second messengers, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG), which stimulate distinct downstream signaling. Recently, it has been reported that PLC signaling is activated by multiple viruses for efficient replication and the virus-induced inflammatory response. In this study, we demonstrated that PLC-specific inhibitor U73122 strongly suppressed porcine reproductive and respiratory syndrome virus (PRRSV) productive infection in cell cultures. The inhibitor affected both viral post-binding cell entry and post-entry processes. The virus infection led to an early transient activation of PLCγ-1 at 0.5 h post-infection (hpi), and sustained event at a stage from 4 to 16 hpi in MARC-145 cells. In addition, U73122 inhibited the activation of p38 MAPK signaling stimulated by PRRSV infection, suggesting that PLC signaling may be associated with the virus infection-induced inflammatory response. Taken together, these studies suggested that PLC signaling played an important role in PRRSV infection or pathogenesis. Keywords: PRRSV; U73122; phospholipase C; PLCγ-1.

Diagnostic accuracy of droplet digital PCR analysis of cerebrospinal fluid for tuberculous meningitis in adult patients

OBJECTIVES

Tuberculous meningitis (TBM) is difficult to diagnose. Digital PCR (dPCR) is a novel method which can quantify trace nucleic acids. This study sought to evaluate the diagnostic accuracy of dPCR analysis of cerebrospinal fluid (CSF) for TBM.

METHODS

We collected CSF specimens from hospitalized TBM and non-TBM patients. Total CSF DNA was purified and the concentrations of Mycobacterium tuberculosis insert sequence 6110 (IS6110) and gyrase subunit B (gyrB) were quantified using droplet dPCR. The receiver operating characteristic curves of dPCR were established and the diagnostic performances were obtained. We also compared the sensitivity of dPCR with routine diagnostic tests.

RESULTS

A total of 101 patients were recruited, 68 of whom suffered from TBM (26 definite, 34 probable and eight possible TBM) and 33 from non-TBM. The sensitivity of IS6110-dPCR assay for total TBM was higher than that of gyrB-dPCR assay (57.4% (44.8-69.3%) vs. 22.1% (12.9-33.8%)), and there was no significant difference for specificity between them (97.0% (84.2-99.9%) vs. 100% (89.4-100.0%)). The sensitivity of IS6110-dPCR in definite TBM was higher than that in probable and possible TBM (73.1% vs. 52.9% and 25.0%, respectively). IS6110-dPCR assay showed a higher sensitivity than smear microscopy (53.3% vs. 6.7%), mycobacterial culture (50.0% vs. 12.5%), IS6110-quantitative PCR (53.1% vs. 21.9%) and Xpert MTB/RIF (70.4% vs. 29.6%). Long anti-tuberculosis treatment time was found to be significantly associated with negative dPCR results.

CONCLUSION

CSF IS6110-dPCR assay is a rapid and sensitive molecular test, which has the potential to be used to enhance the diagnosis of TBM.

Efficacy of intratympanic corticosteroid, intravenous batroxobin and combined treatment for sudden sensorineural hearing loss with type-2 diabetes

BACKGROUND

Intratympanic corticosteroid (IC), intravenous batroxobin (IB) as the treatment for sudden sensorineural hearing loss (SSNHL) has been reported. However, the data on combination therapy (CT) was scarce.

OBJECTIVE

The aim of this retrospective study was to compare the efficacy of IC, IB, and CT in the treatment of SSNHL with diabetes.

MATERIAL AND METHODS

A total of 212 SSNHL patients with diabetes, who were initially treated within 14 days of onset of disease, were divided into three groups by treatment modality. The hearing recovery was evaluated by the results of pure-tone test after completion of treatment. The prognostic factors, including age, severity of initial hearing loss, duration to onset of treatment, and audiometric curve type, were further compared.

RESULTS

There was a significant difference in hearing recovery by the treatment (p < .05). Recovery rates in the CT group were significantly higher in patients with early treatment than with delayed treatment (p = .021). However, duration and recovery rate was not significantly correlated in IC and IB group (p > .05). In patients recieving early treatment, the recovery rate in CT group was significantly higher than that in IC (p = .013) and IB group (p = .029). Regardless of treatment, the recovery rates were higher in patients with flat and ascending audiograms (p < .05).

CONCLUSIONS AND SIGNIFICANCE

Patients receiving combined therapy, especially in the early stage of SSNHL, could achieve significantly superior recovery in the treatment of SSNHL with diabetes, compared with those using IC or IB alone.

The recruitment of extra-intestinal cells to the injured mucosa promotes healing in radiation enteritis and chemical colitis in a mouse parabiosis model

Mucosal healing occurs through migration and proliferation of cells within injured epithelium, yet these processes may be inadequate for mucosal healing after significant injury where the mucosa is denuded. We hypothesize that extra-intestinal cells can contribute to mucosal healing after injury to the small and large intestine. We generated parabiotic pairs between wild-type and tdTomato mice, which were then subjected to radiation-induced enteritis and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. We now show that as compared with singleton mice, mice with a parabiotic partner were protected against intestinal damage as revealed by significantly reduced weight loss, reduced expression of pro-inflammatory cytokines, reduced enterocyte apoptosis, and improved crypt proliferation. Donor cells expressed CD45-, Sca-1+, c-kit+, and CXCR4+ and accumulated around the injured crypts but did not transdifferentiate into epithelia, suggesting that extra-intestinal cells play a paracrine role in the healing response, while parabiotic pairings with Rag1-/- mice showed improved healing, indicating that adaptive immune cells were dispensable for mucosal healing. Strikingly, ablation of the bone marrow of the donor parabionts removed the protective effects. These findings reveal that the recruitment of extra-intestinal, bone marrow-derived cells into the injured intestinal mucosa can promote mucosal healing, suggesting novel therapeutic approaches for severe intestinal disease.

A prospective RCT comparing combined chromoendoscopy with water exchange (CWE) vs water exchange (WE) vs air insufflation (AI) in adenoma detection in screening colonoscopy

Background

A low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC.

Aims

We compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy.

Methods

After split-dose preparation, 480 veterans were randomized to AI, WE and CWE.

Results

Primary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC.

Conclusions

When an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).

High-transmission polarization-dependent active plasmonic color filters

Plasmonic color filters, exhibiting great promise as an alternative for existing colorant-based filters, often only output one fixed color. Developing active color filters with controllable color output will lead to more compact color filter-based devices. In this paper, we present an approach to achieve active color filtering with a polarization-dependent plasmonic structural color filter, which comprises arrays of asymmetric cross-shaped nanoapertures in an ultrathin film of silver. A systematical study for aperture size, array period, and the thickness of silver film dependences of color filter properties is carried out, and strategies for polarization-dependent color filter designing are generated. A polarization-dependent and high tunability of color can be achieved by selecting the appropriate nanostructure parameters, which imply many potential applications.

Correlations of ultrasonic features with severity of liver cancer and p16 expression in patients with liver cancer

This paper analyzes the correlations of ultrasonic features with clinical-pathological manifestations and p16 expression in patients with liver cancer. A total of 84 patients with primary liver cancer were randomly enrolled. The characteristics of liver cancer were examined via conventional ultrasound and contrast-enhanced ultrasound (CEUS) before operation. The p16 protein expressions in liver cancer and para-carcinoma tissues were detected via immunohistochemistry (IHC), and the correlations of p16 positive expression with ultrasound parameters were also analyzed. It was manifested via ultrasound that 6.4% (3/47) of stage I-II liver cancer showed the equal-echo change in portal phase, while others faded and showed the equal-echo change with 32.4% (12/37) of stage III-IV liver cancer. There were no statistically significant differences in ultrasonic features of patients in stage I-II and stage III-IV in the arterial and delayed phases (p>0.05). The positive expression rate of p16 protein in para-carcinoma tissues was 85.71% (72/84) which was significantly higher than that in liver cancer tissues (30.95%, 26/84) (p<0.05). Maximum intensity (IMAX), time to peak (TTP) and mean transit time (mTT) had no statistically significant differences between the p16 positive and negative groups, but there were statistically significant differences in rising slope (RS) and washout time (WT) (p<0.05). Correlation analyses revealed that the positive expression of p16 had no significant correlations with IMAX, mTT and TTP (p>0.05), but it positively correlated with RS (correlation coefficient r=0.377, p<0.05) and negatively correlated with WT (r=-0.410, p<0.05). Conventional ultrasound and CEUS can evaluate the expression of p16 protein in liver cancer repeatedly and non-invasively. The evaluations therefore have great significance in clinical treatment of liver cancer.

[The progress of topical drug delivery to the inner ear for the inhibition of inflammation and fibrosis following cochlear implantation]

Nowadays, more than 300 000 deaf people around the world benefit from cochlea implantation. With the extension of cochlear implantation indications, it has become a research focus for how to apply the anti-inflammatory and anti-fibrotic drugs safely and effectively to better retain residual hearing, as well as to protect hair cells and the spiral ganglion cells from apoptosis. Due to the blood-labyrinth barrier, perioperative systemic steroids are often unable to achieve satisfactory drug concentration in the inner ear. Also, given that higher doses of steroids will cause more serious side effects and sometimes steroids are strictly limited to apply on some patients with certain diseases, the attention has been attracted on topical drug delivery to the inner ear. In this review, the methods of topical drug delivery to the inner ear are divided into four categories: transtympanic injection of liquid solutions, tympanic implantation of drug delivery systems, intracochlear injection and modified implant electrode. The results in each category and up to date progress are reviewed.

Strategy for facial nerve management during surgical removal of benign jugular foramen tumors: Outcomes and indications

OBJECTIVE

Classical surgical management of jugular foramen (JF) tumors usually requires facial nerve rerouting which results in permanent facial palsy in most patients. The purpose of the article is to study the outcomes of different rerouting techniques, and to discuss their indications.

MATERIAL AND METHODS

We retrospectively reviewed 98 patients with JF tumors operated at our center between January 2008 and December 2016 using different surgical approaches with the following procedures for facial nerve management: total anterior rerouting (TR), partial anterior rerouting (PR), and fallopian bridge (FB) technique. The data for facial nerve management, surgical outcome and postoperative facial nerve function were collected from the medical records.

RESULTS

In the study, there were 48 males and 50 females. Of them, 61 (62.2%) were jugular paragangliomas, 22 (22.4%) schwannomas, and 15 (15.3%) meningiomas. Total tumor removal was achieved in 95 (96.9%) patients, while near-total removal was achieved in 3 (3.1%) paragangliomas. TR was applied in 31 (31.6%) patients with PR in 26 (26.5%) patients, and FB in 41 (41.8%) patients. The mean follow-up duration was 39.4±22.6 months, and 2 recurrences of paragangliomas were observed. Seventy-five patients (76.5%) had good facial function (HB I-II) at 1 year after surgery, the patients who received a TR approach presented significantly less HB I-II FN function (48.4%) than those with PR (82.6%, P<0.05) or those with FB technique (95.1%, P<0.001). 21 patients (21.4%) presented new-onset lower cranial nerve dysfunction of which 13 recovered at 1 year after surgery.

CONCLUSION

Facial nerve management in JF tumors should be tailored individually. No-rerouting methods, such as the fallopian bridge technique, bring significantly better results in terms of facial nerve function, which might be performed first during surgery; its indication is based mainly on the tumor type and extent.

Barriers to research among residents in Otolaryngology - Head & Neck Surgery around the world

OBJECTIVES

To document the challenges faced by residents in Otolaryngology - Head & Neck Surgery (OTL-HNS) around the world to successfully complete research projects. The second objective is to assess if the challenges are uniform worldwide.

METHODS

A survey was sent to all OTL-HNS under 45 years old from the 2017 IFOS meeting. This survey was conducted by the YO-IFOS group (Young Otolaryngologists of the International Federation of Otolaryngological Societies). Data was collected for a period of 1 month. Demographic characteristics, information regarding research projects conducted and data concerning perceived barriers to completion of research projects were collected.

RESULTS

Among the 2787 attendees, 928 responded to the survey (response rate=33.3%). Of these 928 answers, 267 responses were from residents/interns in OTL-HNS, while 635 responses were from certified otolaryngologists. The three most frequent obstacles to conducting research projects for trainees were limited dedicated time (64%), insufficient financial resources (55%) and lack of education in research (45%). There was no statistical difference in these barriers among the different countries (P>0.05).

CONCLUSION

This is the first international study that provides insight on trainee's challenges to conduct research projects during residency. Despite the notion that research is essential for generating new knowledge to guide patient care, many residents fail to successfully incorporate research in their surgical curriculum. These obstacles must be addressed by Otolaryngology - Head & Neck Surgery programs in order to facilitate and support resident's research.