Development and validation of an objective virtual reality tool for assessing technical aptitude among potential candidates for surgical training.

BACKGROUND: Good technical skills are crucial for surgeons. Yet although surgical training programs strive to assess technical aptitude when selecting surgical residents, valid assessments of such aptitude are still lacking. Surgical simulators have been proposed as a potentially effective tool for this purpose. The current study aims to develop a technical aptitude test using a virtual reality surgical simulator, and to validate its use for the selection of surgical residents. METHODS: The study had three phases. In Phase 1, we developed an initial version of the technical aptitude test using the Lap-X-VR laparoscopic simulator. In Phases 2 and 3 we refined the test and collected empirical data to evaluate four main sources of validity evidence (content, response process, internal structure, and relationships with other variables), and to evaluate the feasibility and acceptability of the test. Specifically, Phase 2 comprised a review of the test by 30 senior surgeons, and in Phase 3 a revised version of the test was administered to 152 interns to determine its psychometric properties. RESULTS: Both the surgeons and interns rated the test as highly relevant for selecting surgical residents. Analyses of the data obtained from the trial administration of the test supported the appropriateness of the score calculation process and showed good psychometric properties, including reliability (α = 0.83) and task discrimination (mean discrimination = 0.5, SD = 0.1). The correlations between test scores and background variables revealed significant correlations with gender, surgical simulator experience, and video game experience (ps < 0.001). These variables, however, explained together only 10% of the variance in test scores. CONCLUSIONS: We describe the systematic development of an innovative virtual reality test for assessing technical aptitude in candidates for surgical training, and present evidence for its validity, feasibility and acceptability. Further validation is required to support the application of the test for selection, as well as to discern the impact of gender, surgical simulator experience, and video game experience on the fairness of test results. However, the test appears to be a promising tool that may help training programs assess the suitability of candidates for surgical training.

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.

Biological Treatment for Uncontrolled Chronic Rhinosinusitis with Nasal Polyps: Preliminary Real-World Results from a Tertiary Medical Center.

The efficacy of biological treatment for severe uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP) has recently been demonstrated through double-blinded clinical trials. The aim of this study was to provide preliminary real-world experience regarding biological therapy for uncontrolled CRSwNP. The records of patients who received biological treatment in a tertiary medical center between the years 2019 to 2022 were retrospectively reviewed. Patients included in this study were eligible for biological treatment according to the EPOS 2020 criteria. Among patients who had their first follow-up visit <6 months from the treatment initiation, the Sino-Nasal Outcome Test 22 Questionnaire (SNOT-22) score had decreased by 22% (p = 0.01) and the nasal polyp score (NPS) had decreased by 48% (p = 0.05). Among patients who had their first follow-up visit ≥6 months from treatment initiation, the SNOT-22 score had decreased by 40% (p = 0.03) and the NPS had decreased by 39% (p = 0.1). The number of patients who needed systemic steroid treatment had decreased by 68% (p < 0.0001), and the number of patients who needed endoscopic sinus surgery had decreased by 74% (p < 0.0001). These findings correspond with the improvement of clinical symptoms observed in prior randomized clinical trials, thus showing the effectiveness of biologic medications in the treatment of severe CRSwNP in a real-life setting. Although further cohort studies are warranted, our study also suggests evaluating patients at follow-up visits mainly by quality-of-life aspects and investigating longer dosing intervals of dupilumab.

Intra-operative identification of a temporal bone fracture line during cochlear implant surgery: a case report.

BACKGROUND: Temporal bone fractures are divided into otic capsule sparing and otic capsule involving fractures. In the latter, hearing loss, facial nerve paralysis, cerebrospinal fluid leak and meningitis have been reported to occur. The impact of hearing loss can be devastating, especially when occurring in children, with significant risk to speech development and sound localization. In the event of hearing loss, early rehabilitation is therefore of paramount importance. Identification of an intra-operative fracture line with available images and the outcome of such cases has not been reported. CASE PRESENTATION: We present the case of a 31-month-old male with an otic capsule involving temporal bone fracture, who presented with ipsilateral profound hearing loss. After all required work-up had been performed, he was admitted for a cochlear implant insertion. Per- operatively, a clear fracture line was seen at the round window niche, but a normal insertion was performed despite the anticipated potential ossification at the fracture line. The dreaded complications of cerebrospinal fluid otorrhea or non-auditory stimulation post-implant did not occur. The peculiarity of this case was its rarity, which was demonstrated by clear images that showed the fracture line on preoperative imaging and intraoperatively. CONCLUSION: Cochlear implantation in the presence of a visible fracture line is feasible and the surgical procedure must not be aborted at its discovery. In these cases, post-operative bacterial meningitis can occur and should be treated aggressively with systemic antibiotics to avoid contralateral ossification of the labyrinth due to labyrinthitis.

Sinonasal Stent Coated with Sustained-Release Varnish of Mometasone Furoate Inhibits Pro-Inflammatory Cytokine Release from Macrophages: An In Vitro Study.

The aim of the study was to develop a sustained-release varnish (SRV) containing mometasone furoate (MMF) for sinonasal stents (SNS) to reduce mucosa inflammation in the sinonasal cavity. The SNS' segments coated with SRV-MMF or an SRV-placebo were incubated daily in a fresh DMEM at 37 °C for 20 days. The immunosuppressive activity of the collected DMEM supernatants was tested on the ability of mouse RAW 264.7 macrophages to secrete the cytokines' tumor necrosis factor α (TNFα) and interleukin (IL)-10 and IL-6 in response to lipopolysaccharide (LPS). The cytokine levels were determined by respective Enzyme-Linked Immunosorbent Assays (ELISAs). We found that the daily amount of MMF released from the coated SNS was sufficient to significantly inhibit LPS-induced IL-6 and IL-10 secretion from the macrophages up to days 14 and 17, respectively. SRV-MMF had, however, only a mild inhibitory effect on LPS-induced TNFα secretion as compared to the SRV-placebo-coated SNS. In conclusion, the coating of SNS with SRV-MMF provides a sustained delivery of MMF for at least 2 weeks, maintaining a level sufficient for inhibiting pro-inflammatory cytokine release. This technological platform is, therefore, expected to provide anti-inflammatory benefits during the postoperative healing period and may play a significant role in the future treatment of chronic rhinosinusitis.

Mast cells contribute to the resolution of allergic inflammation by releasing resolvin D1.

BACKGROUND: Mast cells are initiators and main effectors of allergic inflammation, together with eosinophils, with whom they can interact in a physical and soluble cross-talk with marked pro-inflammatory features, the Allergic Effector Unit. The pro-resolution role of mast cells, alone or in co-culture with eosinophils, has not been characterized yet. OBJECTIVES: We aimed to investigate select pro-resolution pathways in mast cells in vitro and in vivo in allergic inflammation. METHODS: In vitro, we employed human and murine mast cells and analyzed release of resolvin D1 and expression of 15-lipoxygenase after IgE-mediated activation. We performed co-culture of IgE-activated mast cells with peripheral blood eosinophils and investigated 15-lipoxygenase expression and Resolvin D1 release. In vivo, we performed Ovalbumin/Alum and Ovalbumin/S. aureus enterotoxin B allergic peritonitis model in Wild Type mice following a MC "overshoot" protocol. RESULTS: We found that IgE-activated mast cells release significant amounts of resolvin D1 30 min after activation, while 15-lipoxygenase expression remained unchanged. Resolvin D1 release was found to be decreased in IgE-activated mast cells co-cultured with peripheral blood eosinophils for 30 min In vivo, mast cell-overshoot mice exhibited a trend of reduced inflammation, together with increased peritoneal resolvin D1 release. CONCLUSIONS: Mast cells can actively contribute to resolution of allergic inflammation by releasing resolvin D1.

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.

The impact of vestibular symptoms and electronystagmography results on recovery from sudden sensorineural hearing loss.

OBJECTIVES: Idiopathic sudden sensorineural hearing loss (SSNHL) represents a frequently encountered otological entity, of various types and severity, with an array of associated symptoms including vertigo. This is a devastating life-changing condition with a blurry prognosis. The objective of this study was to determine the clinical association of vestibular impairment by electronystagmography (ENG) and caloric tests, and their ability to predict prognosis. METHODS: An observational, crossectional study was carried out amongst patients admitted with SSNHL. Each consenting patient had an audiometry test performed on admission as well as ENG and caloric tests. Treatment included oral steroids and carbogen with intratympanic steroids used only as salvage treatment. Follow-up was completed after 6 months when hearing gains were evaluated. Finally, an association was sought between the rate of recovery and ENG and caloric test results. RESULTS: Of 35 patients included, marked recovery was seen in patients without vertigo when compared to those with vertigo (p=0.003). A statistically significant association was found between the presence of vertigo and hearing deterioration (p=0.008). More so, normal electronystagmography results were associated with marked recovery (p=0.04). CONCLUSIONS: The vestibular end organs are both subjectively and objectively affected in SSNHL as demonstrated by the abnormal ENG and caloric tests in our study despite the small sample size. Concomitant vestibular involvement carries poorer prognosis and routine identification may help foresee the recovery of patients with SSNHL and as such, aid in patient counseling. ENG and caloric tests are easily available and may be recommended for all patients with SSNHL.

Using Job Analysis for Identifying the Desired Competencies of 21st-Century Surgeons for Improving Trainees Selection.

OBJECTIVE: The current selection for surgical training is based on ineffective methods. In order to identify or to develop more valid selection tools to improve the selection, it is necessary to first define what are the competencies that are most important for success in contemporary surgery. Therefore, the current study aims to identify what competencies are required for success as a surgeon in the 21st-century and to evaluate their relative importance for selection for surgical training. METHODS: Job analysis was conducted using a mixed-methods design. First, 104 senior surgeons from all surgical fields from various hospitals in Israel were interviewed in order to query their perceptions of competencies associated with success as a surgeon. Their answers were coded and analyzed to create a list of important competencies. Next, a larger sample of 1,102 surgeons and residents from all surgical fields completed a questionnaire in which they rated the importance of each competency in the list for success as a surgeon and for selection for surgical training in the 21st-century. RESULTS: Twenty-four competencies (five technical skills, six cognitive abilities, 13 personality characteristics) were identified in the interview analysis. Analysis of the questionnaire's data revealed that all 24 competencies were perceived as important for success as a surgeon in the 21st-century as well as for selection for surgical training. The perceived importance of personality characteristics was higher than both cognitive abilities (p < 0.001) and technical skills (p < 0.001). The results did not differ between different surgical fields. CONCLUSIONS: Twenty-four competencies were identified as important for 21st-century surgeons and for selection for surgical training. Although all competencies were perceived as important, personality characteristics were perceived as more important than technical skills and cognitive abilities. This updated definition of required competencies may aid in developing more valid selection methods of candidates for surgical training.

Allergic Rhinitis: Pathophysiology and Treatment Focusing on Mast Cells.

Allergic rhinitis (AR) is a common rhinopathy that affects up to 30% of the adult population. It is defined as an inflammation of the nasal mucosa, develops in allergic individuals, and is detected mostly by a positive skin-prick test. AR is characterized by a triad of nasal congestion, rhinorrhea, and sneezing. Mast cells (MCs) are innate immune system effector cells that play a pivotal role in innate immunity and modulating adaptive immunity, rendering them as key cells of allergic inflammation and thus of allergic diseases. MCs are typically located in body surfaces exposed to the external environment such as the nasal mucosa. Due to their location in the nasal mucosa, they are in the first line of defense against inhaled substances such as allergens. IgE-dependent activation of MCs in the nasal mucosa following exposure to allergens in a sensitized individual is a cardinal mechanism in the pathophysiology of AR. This review is a comprehensive summary of MCs' involvement in the development of AR symptoms and how classical AR medications, as well as emerging AR therapies, modulate MCs and MC-derived mediators involved in the development of AR.

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.

Tranexamic acid administration practice in otolaryngology head & neck surgery; international survey.

PURPOSE: Tranexamic acid (TXA) is a potent pro-coagulation drug. Pre-operative, preventive TXA administration and TXA use for active bleeding are established treatments in many medical situations; yet, less is known about its use in otolaryngology head and neck surgery practice. The primary study goals were: MATERIALS AND METHODS: This is an international survey exploring TXA administration strategy. The electronic, anonymous, questionnaire was emailed to all registered Israeli and American Otolaryngology Head and Neck Surgery (OHNS) physicians, investigating TXA administration: RESULTS: Overall, 317 otolaryngologists participated in the study. TXA was administered to 40.5 % of the pediatric population and 50 % of the adult patients when needed. Epistaxis was the most common indication for TXA administration (48-55 %). A small number of otolaryngologists, 4-13 %, recommended preventive TXA for various operations. More surgeons include TXA in their practice and adjusted the dose according to renal function in academic compared to non-academic medical centers and among otolaryngologists practicing in Israel compared to the United States. CONCLUSIONS: TXA is provided by many otolaryngologists to treat active epistaxis but to a substantially lesser extent as a preventive measure. TXA is given to children and adults, some with substantial comorbidities. Treatment is more common among surgeons working in academic institutes and medical centers in Israel.

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.

Sustained release varnish containing chlorhexidine for prevention of Streptococcus mutans biofilm formation on voice prosthesis surface: an in vitro study / Barniz de liberación sostenida que contiene clorhexidina para la prevención de la formación de biopelículas de Streptococcus mutans en la superficie de la prótesis de voz: un estudio in vitro

Objectives: In this study, we aimed to develop a novel, sustained release varnish (SRV) for voice prostheses (VP) releasing chlorhexidine (CHX), for the prevention of biofilm formation caused by the common oral bacteria Streptococcus mutans on VP surfaces. Methods: This study was performed in an in vitro model as a step towards future in vivo trials. VPs were coated with a SRV containing CHX (SRV-CHX) or SRV alone (placebo-SRV) that were daily exposed to S. mutans. The polymeric materials of SRV were composed of ethylcellulose and PEG-400. Biofilm formation was assessed by DNA quantification (qPCR), crystal violet staining, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and kinetics experiments. Results: The amount of DNA in the biofilms formed by S. mutans on VP surfaces coated once with SRV-CHX (1.024 ± 0.218 ng DNA/piece) was 58.5 ± 8.8% lower than that of placebo-SRV-coated VPs (2.465 ± 0.198 ng DNA/piece) after a 48-h exposure to S. mutans (p = 0.038). Reduced biofilm mass on SRV-CHX-coated VPs was visually confirmed by CLSM and SEM. CV staining of SRV-CHX single-coated VPs that have been exposed to S. mutans nine times showed a 98.1 ± 0.2% reduction in biofilm mass compared to placebo-SRV-coated VPs (p = 0.003). Kinetic experiments revealed that SRV-CHX triple-coated VPs could delay bacterial growth for 23 days. Conclusions: Coating VPs with SRV-CHX has an inhibitory effect on biofilm formation and prevents bacterial growth in their vicinities. This study is a proof-of-principle that paves the way for developing new clinical means for reducing both VPs’ bacterial biofilm formation and device failure.(AU)

Sustained release varnish containing chlorhexidine for prevention of Streptococcus mutans biofilm formation on voice prosthesis surface: an in vitro study.

OBJECTIVES: In this study, we aimed to develop a novel, sustained release varnish (SRV) for voice prostheses (VP) releasing chlorhexidine (CHX), for the prevention of biofilm formation caused by the common oral bacteria Streptococcus mutans on VP surfaces. METHODS: This study was performed in an in vitro model as a step towards future in vivo trials. VPs were coated with a SRV containing CHX (SRV-CHX) or SRV alone (placebo-SRV) that were daily exposed to S. mutans. The polymeric materials of SRV were composed of ethylcellulose and PEG-400. Biofilm formation was assessed by DNA quantification (qPCR), crystal violet staining, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and kinetics experiments. RESULTS: The amount of DNA in the biofilms formed by S. mutans on VP surfaces coated once with SRV-CHX (1.024 ± 0.218 ng DNA/piece) was 58.5 ± 8.8% lower than that of placebo-SRV-coated VPs (2.465 ± 0.198 ng DNA/piece) after a 48-h exposure to S. mutans (p = 0.038). Reduced biofilm mass on SRV-CHX-coated VPs was visually confirmed by CLSM and SEM. CV staining of SRV-CHX single-coated VPs that have been exposed to S. mutans nine times showed a 98.1 ± 0.2% reduction in biofilm mass compared to placebo-SRV-coated VPs (p = 0.003). Kinetic experiments revealed that SRV-CHX triple-coated VPs could delay bacterial growth for 23 days. CONCLUSIONS: Coating VPs with SRV-CHX has an inhibitory effect on biofilm formation and prevents bacterial growth in their vicinities. This study is a proof-of-principle that paves the way for developing new clinical means for reducing both VPs' bacterial biofilm formation and device failure.

Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study.

The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureussubsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureussubsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureussubsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureussubsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.