This study assesses in vitro and in silico the performance of a multi side-hole catheter (SHC) by investigating embolic particle transport and distribution in arterial bifurcations. Two catheter designs (SHC and end-hole catheter, EHC) and two bifurcation types (Y-shaped and side-branch) were analyzed. In vitro analyses employed a hydraulic test bench with a scaled-up arterial system, using a water-glycerin mixture as bloodmimicking fluid. Results showed that SHC produced particle distributions closely aligned with flow splits, while EHC concentrated particles in the branch directly facing the catheter tip. In silico simulations demonstrated good agreement with experimental data, with an average outlet-to-outlet distribution difference of 3.1 percentage points. Clinically, these findings are particularly relevant for radioembolization, where the SHC, by promoting sufficient particle dispersion in the arterial lumen, may enhance tumor coverage in multi-segment disease with a single injection. The validated implementation of helical-flow conditions further enhances the physiological accuracy of both experimental and computational models. Overall, this work highlights the critical role of catheter design in optimizing microsphere delivery, treatment efficacy, and personalized planning in transcatheter endovascular therapies.

Abstract The emergence of the endoscope has ushered in a new era in ear surgery. Though the fundamental elements of surgery have not changed, endoscopic techniques have permitted new opportunities in visualization and education. This chapter discusses some of the advantages and disadvantages of endoscopic ear surgery, technical considerations for specific procedures, and relevant outcomes data.

INTRODUCTION:Adults with substantial residual low‑frequency (LF) hearing are increasingly considered for cochlear implantation. This study evaluated hearing preservation and speech performance outcomes using a slim perimodiolar electrode (CI632) in adults under expanded indications. METHODS:In a prospective, open label, single arm feasibility trial at three U.S. tertiary centers, ten adults with LF thresholds ≤50 dB HL at 500 Hz, sloping high frequency loss, and aided CNC scores ≤60% in the ear to be implanted received the CI632 device. Participants were followed for 12 months postactivation. Assessments included air and bone conduction audiometry, electrode impedances, unilateral and bilateral CNC in quiet and AzBio sentences in noise, patient reported outcomes, and postoperative CT imaging. RESULTS:The LF pure tone average (125-500 Hz) showed a mean shift of 19.3 dB at activation and remained stable at 22.4 dB at 12 months. Impedances were stable across visits. Due to preserved acoustic hearing, all participants utilized electric-acoustic stimulation in the implant ear. Speech recognition improved significantly across all measures, with an average improvement at 12 months ranging from 22 to 54 percentage points, depending on the test. Patient reported outcomes also improved. CT imaging confirmed scala tympani placement for all electrodes, with a mean angular insertion depth of 406.6°. CONCLUSION:The slim perimodiolar electrode can preserve LF acoustic hearing in adults implanted under expanded indications, supporting meaningful objective and subjective benefit. Hearing preservation outcomes in this cohort exceeded those typically reported for perimodiolar arrays, and preserved LF hearing contributed strongly to improved speech understanding in noise.

INTRODUCTION:The Osia 2 System is an active transcutaneous bone conduction hearing device. From 2022 to 2024, an FDA-approved, prospective, multi-center, open-label clinical trial was run through seven US-based centers. This trial sought to demonstrate the safety and efficacy of the Osia2 system in children aged 5-11 to expand indications. METHODS:Fifty children aged 5-11 years (mean 7.4 years), presenting with conductive/mixed hearing loss (N = 37) or single-sided deafness (N = 13) were enrolled prospectively and followed to 12 months post-surgery. Intraoperative findings were collected via surgeon questionnaire. Safety outcomes included adverse events/complications tracked out to 12 months post-surgery. Efficacy outcomes included hearing sensitivity, speech perception in quiet and noise, hours of use, retention, and a parental questionnaire. RESULTS:Fifty subjects were implanted. Forty-nine subjects completed the trial through the 12-month post-implantation endpoint. Surgical bone stock was good in all subjects. Bone bed polishing was required in 36%. 34% (N = 17/50) reported a procedure and/or device-related adverse event. The majority of these were minor and expected issues postoperatively. No patients required explant. Patients experienced statistically significant improvements in word scores (CNC), speech in noise testing (BKB-SIN), and pure tone averages at 6 months post-implantation compared to the pre-surgical unaided condition. Retention scores were good at the study endpoint. Mean daily use was 9.8 +/- 3.2 h/day. CONCLUSION:The data from this trial suggest the Osia 2 system is safe and effective to use in children aged 5-11. FDA clearance for this new age indication was approved in spring 2024. LEVEL OF EVIDENCE: 3: TRIAL REGISTRATION:This study was part of a Multi-center prospective trial, submitted to and approved by the FDA (Clinicaltrials.gov number: NCT05000931; FDA IDE number: G2000325).

Objective To assess practice patterns regarding antibiotics prophylaxis in otologic surgery in the United States. Study Design Cross-sectional study. Setting Tertiary care center. Subjects Members of American Neurotology Society (ANS). Intervention Nationwide survey. Main Outcome Measures Prevalence of antibiotic prescribing among surgeons performing the following six ear surgical procedures: cochlear implantation, tympanoplasty with a clean ear, tympanoplasty with active drainage, cholesteatoma surgery without evidence of infection, cholesteatoma surgery with evidence of infection, and stapedectomy. Results Seventy-three surgeons completed the survey (15.21% response rate). Twenty-seven percent had more than 25 years in experience, and 18% had 0 to 5 years of experience. Antibiotic prescribing practices varied by procedure: cochlear implantation (64.4%, median 5 d), tympanoplasty (clean ear: 23.3%, median 5 d; active drainage: 53.4%, median 7 d), cholesteatoma surgery (no infection: 30.1%, median 7 d; with infection: 58.9%, median 7 d), and stapedectomy (34.2%, mean 5 d). Cephalosporins were preferred for noninfected procedures, whereas amoxicillin dominated for active infections. Conclusions Prophylactic oral antibiotics varies for ear surgery, with higher usage for procedures with active infection and a preference for cephalosporins in noninfected cases. These findings underscore the need for the development and dissemination of standardized, evidence-based recommendations.

BACKGROUND AND OBJECTIVES:The retrosigmoid (RS) and translabyrinthine (TL) approaches are commonly used for vestibular schwannoma resection, each with distinct risks and benefits. This study compared short-term outcomes and recovery between the two approaches. METHODS:We retrospectively reviewed 301 patients who underwent vestibular schwannoma resection using the RS (n = 125) or TL (n = 176) at a single institution from 2008 to 2024. Data included demographics, tumor characteristics, surgical details, preoperative symptoms, postoperative complications, length of stay, and discharge disposition. The primary endpoint was home disposition. Secondary endpoints were length of stay and complication rates. Univariable and multivariable logistic regression identified predictors of home disposition. RESULTS:RS patients had larger tumors (27.0 ± 11.3 mm vs 20.3 ± 8.1 mm, P < .001), higher rates of serviceable hearing (48.4% vs 25.2%, P < .001), and more frequent lumbar drain use (73.6% vs 11.4%, P < .001). TL patients were more often discharged home (82.4% vs 68.8%, P = .006) and had lower rates of postoperative gait imbalance (6.3% vs 19.2%, P < .001), diplopia (0.6% vs 4.8%, P = .016), and cerebrospinal fluid leak requiring repair (9.7% vs 1.6%, P = .005). On multivariable analysis, younger age and smaller tumor size were the only independent predictors of home disposition; surgical approach was not. CONCLUSION:TL resection was associated with fewer complications and more frequent discharge to home, but surgical approach did not independently predict recovery. These findings support the use of either approach in selected patients, emphasizing tumor size, comorbidities, and preoperative symptoms in surgical planning.

OBJECTIVE:Characterize the sensitivity and specificity of TransImpedance Matrix (TIM) recordings compared with x-rays in detecting cochlear implant tip foldovers. STUDY DESIGN:Retrospective. SETTING:Multi-institutional, academic and private surgery centers. PATIENTS:Patients 6 months and older undergoing cochlear implantation. INTERVENTIONS:After cochlear implant array insertion, intraoperative TIM recordings and x-rays were conducted to confirm appropriate placement. If a foldover was identified, repeat insertion, followed by TIM and x-ray, was performed. MAIN OUTCOME MEASURES:Presence of tip foldovers as determined by TIM recordings and x-rays. RESULTS:There were 13 tip foldovers out of 484 insertions, yielding a 2.7% tip foldover rate. Using x-rays as the "gold standard," TIM recordings showed 100% sensitivity, 99.6% specificity, 84.6% positive predictive value (PPV), and 100% negative predicative value in detecting tip foldovers. The x-ray images for two TIM-identified tip foldovers were interpreted as normal intraoperatively (apparent false positives), but then were interpreted as foldovers when presented to the operating surgeon postoperatively in a blinded fashion. If these false positives had been reclassified as true positives, TIM specificity and PPV would both improve to 100%. CONCLUSIONS:These results provide further support regarding the utility of TIM recordings to evaluate appropriate cochlear implant electrode array position. Despite the low tip foldover rate reported across the literature and within this study, this multicenter patient group provided a large sample size to calculate the sensitivity and specificity of TIM recordings in identifying tip foldovers. Compared with the reference-standard, x-ray imaging, TIM recordings show equivalent, and in some cases superior, performance in identification of tip foldovers. Thus, use of TIM can potentially preclude the need for routine intraoperative x-rays without compromising patient care.

Numerical fluid-particle dynamics simulations, such as Computational Fluid Dynamics (CFD), are widely used to study blood flow and microsphere transport in medical treatments like radioembolization (RE), a therapy for unresectable liver tumors. RE involves injecting 90Y-labeled microspheres via a microcatheter into a hepatic artery to irradiate cancer cells. This study uses simulations on three patient-specific hepatic arteries to evaluate microsphere distribution in RE, focusing on two catheter designs: a standard end-hole catheter (EHC) and a novel multi side-hole catheter (SHC).Key parameters include cancer scenario and catheter tip position. Three performance indexes are introduced: the matching deviation index (MDI), targeting deviation index (TDI), and tumor-flow deviation index (TFDI). Results show the SHC outperforms the EHC with better MDI (3.67 vs. 8.36 percent points) and TDI (6.04 vs. 10.24 percent points) values, suggesting the SHC's cross-flow effect improves microsphere dispersion and alignment with flow split. The TDI values for SHC often match the TFDI, making the latter a potential performance predictor.The SHC demonstrates superior performance when tumors are located downstream from the catheter tip, while for localized tumors, superselective treatment is recommended, minimizing the catheter's impact on therapy.

The slot-die coating process plays an important role in the industry, as it is employed in many different fields. The characteristics of the final application are determined by the flow between the die and the roller. This research paper aims to develop a mathematical model of such flow that takes into account the roller deformations caused by high pressure values reached by the coating fluid. This elastohydrodynamic model is made up of a coupling between the mathematical model of the flow and the mathematical model of the roller deformations. Model resolution is undertaken numerically by deforming the flow domain according to the roller deformations using computational fluid dynamics and computational solid mechanics techniques. For its part, the finite volume method is used to perform the flow model analysis and the finite element method is employed to deal with roller deformations. The results obtained from this model give information on the flow pressure distribution, coating gaps, meniscus position, extent of roller deformations in the coating flow, and the influence of different operating conditions. The information obtained from this study is valuable for industrial applications, as it gives insights into the coating process that can help manufacturers to define a suitable combination of operating parameters in order to obtain coating applications that meet quality and performance requirements.

The temperature of melt blowing (MB) and melt spun fibers is frequently measured using infrared thermography (IRT). However, measurements are affected by the size and curvature of the fiber and by reflected radiation from the nozzle. A procedure was developed to obtain accurate measurements of fiber temperature, which corrects fiber size, fiber curvature, and reflected radiation. This procedure is more general than the ones used so far to correct fiber temperature because it corrects the three abovementioned factors using a single correction formula, this being the first time that fiber temperature correction for reflected radiation has been accounted for. It is also more accurate because it uses the local fiber diameter to correct fiber curvature, instead of mean fiber diameter. The procedure was used to measure the temperature of MB adhesive fibers produced by two multi-hole nozzle designs, the results indicating that, in melt blowing applications, the distortion caused by fiber curvature and reflected radiation on the measurement proves to be far more significant than that caused by fiber size, while correction generally leads to an increase in fiber temperature. Considerations as to the effect of different parameters on temperature correction, as well as the quality of thermographic images, are also provided throughout the text. The conclusions emerging from this study allow more accurate temperature measurements of melt blown and melt spun fibers to be obtained.

Objective Evaluate the sensitivity and financial costs of Trans-Impedance Matrix recordings, Spread of Excitation functions, and x-rays in detecting cochlear implant tip foldovers Setting Tertiary academic medical center Patients 113 ears of 108 patients Interventions Following cochlear implantation and before concluding surgery, intraoperative Trans-Impedance Matrix recordings, Spread of Excitation functions, and x-rays were conducted to evaluate presence of tip foldover. Main Outcome Measures Presence of tip foldover; recording time necessary for and costs of Trans-Impedance Matrix, spread of excitation, and x-rays. Results There were six tip foldovers. Trans-Impedance Matrix showed 100% sensitivity, 100% specificity, 100% positive predictive value, and 100% negative predicative value in detecting tip foldovers. Spread of excitation showed 29% sensitivity, 99% specificity, 67% positive predictive value, and 95% negative predicative value. Trans-Impedance Matrix recordings were completed significantly faster than spread of excitation and x-rays. Elimination of x-rays from our intraoperative workflow results in a twofold cost reduction. Conclusion Trans-Impedance Matrix recordings have potential great clinical utility in evaluating proper CI placement intraoperatively and reducing costs of surgery while not compromising patient care. Given the low tip foldover rate, a multicenter study is in progress to evaluate the sensitivity, specificity, positive predictive value, and negative predicative value of Trans-Impedance Matrix in a larger dataset. This can provide better guidance to cochlear implant clinics interested in evaluating the impact of using Trans-Impedance Matrix on patient care as well as the economics of reducing use of intraoperative imaging.

This research is based on computational fluid dynamics simulations of water and microbubble flow within the tank of a lamellar DAF (L-DAF) clarification system operating under high-rate DAF conditions (12–30 m/h). Firstly, performance of the DAF tank with lamellae was evaluated under two operating conditions in which the flow was either short-circuited or stratified in the absence of lamellae. In addition, the improvement in bubble removal efficiency achieved by the incorporation of lamellae in each scenario was assessed. Secondly, an in-depth analysis was conducted of the flow that develops in the separation zone as a result of placing the lamella pack in that part of the tank. The significant density difference that the lamellae cause to exist between the bubble blanket and clarified water below is responsible for the complex three-dimensional flow observed between the two regions. Analysis of this flow showed a previously undescribed mechanism in which the density gradient plays a crucial role in preventing bubbles from passing through the lamellae and ultimately escaping with the effluent. Finally, the effect of hydraulic loading on the bubble removal efficiency of the L-DAF tank under consideration was researched, and it was found that an L-DAF with a height/length ratio of 0.72 is able to operate at hydraulic loading close to 30 m/h, evidencing good debubbling performance.

Air consumption in the melt-blowing process represents one of the major costs involved in the production of thin fibers. In the present work an experimental study is conducted on two multihole melt-blowing nozzles for manufacturing styrene-butadiene-styrene based hot-melt adhesive fibers in order to assess their fiber attenuation capability. With this purpose in mind, fiber diameter, fiber temperature, fiber bending, and air velocity were measured experimentally, and the steady-state quasi-one-dimensional longitudinal momentum equation of the slender fiber was integrated numerically in the nozzle postextrusion region and solved for aerodynamic force prefactor K, as it appears in Matsui's drag coefficient correlation. A measure of fiber attenuation efficiency is proposed in terms of prefactor K and other nozzle geometrical and process operating parameters, which indicates the capacity of the nozzle to produce thin fibers with low air consumption. The results indicate that increasing nozzle air tilt angle, prefactor K, and air-polymer kinematic viscosity ratio in turn increases fiber attenuation efficiency. Working conditions are provided for each nozzle design that allow thin hot-melt-adhesive melt-blown fibers to be produced in a cost-effective manner. Furthermore, a formula is provided for estimating the melt-blown fiber attenuation rate in terms of multihole nozzle geometrical and process operating parameters. The results obtained in this work will help to reduce unnecessary energy consumption of melt-blowing equipment.

The effectiveness of a close-coupled gas atomisation process largely depends on the operational and the geometric variables. In this study, Computational Fluid Dynamics (CFD) techniques are used to model and simulate the gas flow in the melt nozzle area for a convergent-divergent, close-coupled gas atomiser in the absence of the melt stream. Firstly, a reference case, in which the atomisation gas is nitrogen at 50 bar and a supersonic gas nozzle with a throat width of L0 has been modelled, is presented. Then, the influence of both the inlet gas pressure and this design parameter are investigated, comparing the numerical results provided by simulations varying the inlet pressure from 5 to 80 bar and modelling different convergent-divergent gas nozzles with throat widths of 0.29 center dot Lo, 0.5 center dot Lo, 0.77 center dot Lo and 2 center dot Lo respectively. The simulation results show how similarly these two parameters modify gas mass flow rates, gas velocity fields, aspiration pressures in the melt delivery tube or the size of the recirculation zones below the melt nozzle. Therefore, it can be stated that this geometric variable of the gas nozzle may be as relevant as the inlet pressure in the atomisation process. The most important novelty of this study is related to experimental validation of the numerical results using the Particle Image Velocimetry (PIV) technique and through direct measurements of gas mass flow rates, with a clear correlation between simulated and measured data. Moreover, some results obtained with experimental atomisations using copper and nitrogen are also presented. The experimental results show that finer powders are produced by increasing the

OBJECTIVE:To evaluate the predictors of remnant tumor regrowth and need for salvage therapy after less than gross total resection (GTR) of vestibular schwannoma (VS).STUDY DESIGN:Retrospective chart review.SETTING:Tertiary neurotologic referral center.PATIENTS:Patients who underwent VS resection between 2008 and 2019 either with GTR, near total resection (NTR), and subtotal resection (STR).INTERVENTIONS:Microsurgical resection, salvage radiosurgery.MAIN OUTCOME MEASURES:Regrowth free interval, salvage free interval, tumor doubling rate.RESULTS:Three hundred eighty five cases (GTR = 236, NTR = 77, and STR = 71) from 2008 to 2019 were included. STR cohort had much larger and complex tumors with significant differences in tumor volume, ventral extension and brainstem compression (p  < 0.001). On single predictor analysis, tumor volume, ventral extension, brainstem compression as well as STR strategy was associated with significant increased risk of regrowth and need for salvage therapy. Multivariate analysis revealed STR strategy as significant predictor of regrowth (hazard ratio 3.79, p  < 0.0005). Absolute remnant volume and extent of resection (EOR) did not predict regrowth. A small proportion of cases (NTR = 4%, STR = 15%) eventually needed salvage radiosurgery with excellent ultimate local tumor control with no known recurrence to date.CONCLUSIONS:Conservative surgical strategy employing NTR or STR can be employed safely in large and complex VS. While there is increased risk of regrowth in the STR cohort, excellent local control can be achieved with appropriate use of salvage radiosurgery. No disceret radiologic or operative predictors of regrowth were identified.

This paper presents a Computational Fluid Dynamics (CFD) model of a pilot scale dissolved air flotation (DAF) tank. A Multiphase Mixture model was used to analyse the influence of bubble sizes on the formation of a stratified flow structure. Critical bubble diameter is defined as the size of the bubble that implies the equality of the bubble rising velocity and flow downward velocity in the separation zone (SZ). The fact as to whether using air bubble sizes which are greater or less than the critical diameter value significantly affects the air content, flow structure and the limit of the whitewater blanket inside the SZ is assessed. The study was carried out using two approaches, namely, mono- and multi-diameter. The results obtained via the mono-diameter approach proved to be closely in line with experimental data when air concentration in the SZ had almost, but not quite, a constant value. However, it failed to predict the case of the progressive decrease in air below half of SZ height. A combined effect of bubbles with different rising speed was required to reproduce a smooth air profile curve, as measured experimentally. In this context, a multi-diameter approach is deemed to be a suitable method for reproducing the stratified structure. In addition, this approach offers the chance to study bubble size distribution inside the SZ domain.

The high demand for quality in the manufacture of absorbent hygiene products requires the adhesive bonds between layers to be as uniform as possible. An experimental study was conducted on two industrial multihole melt blowing nozzle designs used for hot-melt adhesive applications for hygiene products, in order to study two defects that influence the quality of the adhesive bond: fibre breakup, resulting in contamination, and the presence of shots, undesirable lumps that end up in the finished product. To this end, the fibre dynamics were captured at the nozzle exit region by using high-speed imaging. From the results it was observed that die drool is the main source of shot formation, while fibre breakup occurs as a result of applying a sufficiently large force in the direction perpendicular to the fibre. In addition, three dimensionless parameters were defined, the first two being the air-polymer flux ratio and the dimensionless temperature ratio, both of which represent the operating conditions, and the remaining one being the force ratio, which represents the nozzle geometry. The effect of these parameters on fibre breakup and shot formation was studied and the results indicate that both the operating conditions and the nozzle geometry were responsible for the onset of the fibre breakup and for the formation of shots. More precisely, both defects turned out to be dominated by the air-polymer flux ratio and the air tilt angle. The results that emerge from this study are useful for the enhancement of industrial melt blowing nozzles.

Radioembolization (RE) is a medical treatment for primary and secondary liver cancer that involves the transcatheter intraarterial delivery of micron-sized and radiation-emitting microspheres, with the goal of improving microsphere deposition in the tumoral bed while sparing healthy tissue. An increasing number of in vitro and in silico studies on RE in the literature suggest that the particle injection velocity, spatial location of the catheter tip and catheter type are important parameters in particle distribution. The present in silico study assesses the performance of a novel catheter design that promotes particle dispersion near the injection point, with the goal of generating a particle distribution that mimics the flow split to facilitate tumour targeting. The design is based on two factors: the direction and the velocity at which particles are released from the catheter. A series of simulations was performed with the catheter inserted at an idealised hepatic artery tree with physiologically realistic boundary conditions. Two longitudinal microcatheter positions in the first generation of the tree were studied by analysing the performance of the catheter in terms of the outlet-to-outlet particle distribution and split flow matching. The results show that the catheter with the best performance is one with side holes on the catheter wall and a closed frontal tip. This catheter promotes a flow-split-matching particle distribution, which improves as the injection crossflow increases.

OBJECTIVE:To investigate the prevalence of vestibular migraine (VM) in a cohort of patients with radiologic confirmation of superior canal dehiscence (SCD) and to compare management of superior canal dehiscence syndrome (SCDS) in patients with and without comorbid VM.STUDY DESIGN:Retrospective review of a SCD database.SETTING:University-based tertiary medical center.PATIENTS:Ninety-one patients identified with SCD from 2009 to 2017.INTERVENTIONS:None.MAIN OUTCOME MEASURES:Coincidence of VM and SCD, and resolution of symptoms.RESULTS:Ninety-one patients with SCD met the inclusion and exclusion criteria. VM was diagnosed in 36 (39.6%) patients. Of those receiving medical therapy for VM alone, five (45.5%) reported symptom resolution, five (45.5%) reported partial improvement, one (9.1%) had no change, and none worsened. Fifteen patients (41.7%) were treated with both surgery (for SCD) and medical therapy (for VM). Seven (46.7%) reported symptom resolution, seven (46.7%) reported partial improvement, and one (6.7%) worsened. There was no statistically significant difference in symptom resolution between SCD + VM patients who were treated medically compared with those treated with medical therapy and surgery (p = 0.951). There was no significant difference in symptom resolution after surgery between SCD + VM and SCD-only cohorts (p = 0.286).CONCLUSIONS:This is the first study describing the incidence of VM in a cohort of patients with SCDS. The symptoms of VM confound those of SCDS and unrecognized or undertreated VM may contribute to surgical failure in SCDS. Therefore, we recommend a high index of suspicion for VM in patients with SCDS and a trial of medical therapy in the setting of suspected VM.

OBJECTIVES:1) To analyze outcomes of cholesteatoma resection utilizing postauricular microscopic and endoscopic ear surgery (EES) approaches.2) To analyze predictors of residual and recurrent cholesteatoma. STUDY DESIGN:Retrospective cohort study. SETTING:Tertiary referral center. PATIENTS:Three hundred seventy-five adult and pediatric patients with cholesteatoma (2012-2017). INTERVENTIONS:Patients underwent surgical resection of cholesteatoma with EES (n = 122) and microscopic (n = 253) approach. MAIN OUTCOME MEASURES:Residual cholesteatoma, recurrent cholesteatoma, second-look procedures. RESULTS:The endoscopic cohort included significantly more pediatric cases (p = 0.0008). There was no difference in laterality, gender distribution, congenital or acquired cholesteatoma, and revision cases between the cohorts. Out of 122 EES cases, 16 (13%) developed residual disease and 9 (7%) developed recurrent disease. Of 253 microscopic cases 16 (6%) developed residual disease while 11 (4%) developed recurrent disease. Second look procedures were more commonly used in EES cohort (50 vs 18%). Single predictor analysis revealed 12 predictors for residual disease and 5 for recurrent disease. Multivariable model identified pediatric case distribution and higher disease stage to be significant predictors for both residual (p = 0.04, 0.007) and recurrent disease (p = 0.02, 0.01). EES approach was associated with a weak significance for residual disease (p = 0.049) but not recurrent disease (p = 0.34). CONCLUSIONS:EES approach for cholesteatoma resection seems to perform similarly to microscopic approach with no difference in rates of recurrent disease. However, it is associated with a higher rate of residual disease; this may be a reflection of a greater rate of second look procedures done in this group.