21 research outputs found
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False-Positive Cholesteatomas on Non-Echoplanar Diffusion-Weighted Magnetic Resonance Imaging.
ObjectivesTo investigate false-positive findings on non-echoplanar (non-EPI) diffusion-weighted magnetic resonance imaging (DWI) in patients under surveillance post-cholesteatoma surgery.Study design, setting, subjects, and methodsA retrospective review was performed on patients diagnosed with cholesteatoma who underwent surgical resection and were then followed by serial non-EPI DWI using half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence. All patients had at least two annual follow-up imaging studies.ResultsFalse-positive findings were identified in four patients. The size of the suspected lesions was 4 to 12 mm. Otoendoscopy was used during all primary cases and Argon laser was used in one case. In all cases, the entire cholesteatoma was removed, and no residual disease was detected at the end of the procedures. One patient underwent revision surgery but only cartilage graft was found in the area of concern. All patients had stable or resolved hyperintense areas in the subsequent HASTE sequences.ConclusionFalse positive findings can occur with non-EPI DWI MRI and patients need to be counseled accordingly before revision surgery. Decreasing intensity and dimension of a suspected lesion and a positive finding in an area other than the location of the initial cholesteatoma may favor a false positive. If a false positive finding is suspected when the surgeon is confident of complete resection of the cholesteatoma, an MRI can be repeated in 6 to 12 months to assess changes in the dimension and intensity of the area of concern. Cartilage grafts may cause restricted diffusion on DWI sequences
Loudness and acoustic parameters of popular children's toys
ObjectiveThis project was conducted to evaluate the loudness and acoustic parameters of toys designed for children. In addition, we investigated whether occluding the toys' speaker with tape would result in a significant loudness reduction; thereby potentially reducing the risk of noise induced hearing loss.MethodsTwenty-six toys were selected after an initial screening at two national retailers. Noise amplitudes at 0.25, 0.5, 1, 2, 4, and 8kHz were measured using a digital sound level meter at a distance of 0 and 30cm. The toys' speakers were then occluded using adhesive tape and the same acoustic parameters were re-measured.ResultsMean maximum noise amplitude of the toys at 0cm and 30cm was 104dBA (range, 97-125dBA) and 76dBA (range, 67-86dBA), respectively. Mean maximum noise amplitude after occlusion at 0cm and 30cm distances was 88dBA (range, 73-110dBA) and 66dBA (range, 55-82dBA), respectively, with a p-value <0.001.ConclusionsProper use of the loudest toys at a distant of 30cm between the speaker and the child's ear will likely not pose a risk of noise-induced hearing loss. However, since most toys are used at closer distances, use of adhesive tape is recommended as an effective modification to decrease the risk of hearing loss
Synthesis of Ketodiesters to Explore the Photodecarbonylation Reaction
II. Solid-state photodecarbonylation is a promising method for the preparation of functionalized ring systems of varying sizes. The recombination of the sigma-bonds yields a new ring system. The photochemical reactivity of dimethyl 11-oxobenzo[c,h]bicycle[4.4.1]undeca-3,8-dienel,6-dicarboxylate in the solid-state resulted in a highly efficient synthesis of the corresponding bicyclic compound. Additional functionalized ring systems were synthesized to investigate the limitations of the photodecarbonylation reaction. The objective of this project is to investigate the scope and limitation of the photodecarbonylation reactio
Estimation of Nasal Tip Support Using Computer-Aided Design and 3-Dimensional Printed Models.
ImportancePalpation of the nasal tip is an essential component of the preoperative rhinoplasty examination. Measuring tip support is challenging, and the forces that correspond to ideal tip support are unknown.ObjectiveTo identify the integrated reaction force and the minimum and ideal mechanical properties associated with nasal tip support.Design, setting, and participantsThree-dimensional (3-D) printed anatomic silicone nasal models were created using a computed tomographic scan and computer-aided design software. From this model, 3-D printing and casting methods were used to create 5 anatomically correct nasal models of varying constitutive Young moduli (0.042, 0.086, 0.098, 0.252, and 0.302 MPa) from silicone. Thirty rhinoplasty surgeons who attended a regional rhinoplasty course evaluated the reaction force (nasal tip recoil) of each model by palpation and selected the model that satisfied their requirements for minimum and ideal tip support. Data were collected from May 3 to 4, 2014.ResultsOf the 30 respondents, 4 surgeons had been in practice for 1 to 5 years; 9 surgeons, 6 to 15 years; 7 surgeons, 16 to 25 years; and 10 surgeons, 26 or more years. Seventeen surgeons considered themselves in the advanced to expert skill competency levels. Logistic regression estimated the minimum threshold for the Young moduli for adequate and ideal tip support to be 0.096 and 0.154 MPa, respectively. Logistic regression estimated the thresholds for the reaction force associated with the absolute minimum and ideal requirements for good tip recoil to be 0.26 to 4.74 N and 0.37 to 7.19 N during 1- to 8-mm displacement, respectively.Conclusions and relevanceThis study presents a method to estimate clinically relevant nasal tip reaction forces, which serve as a proxy for nasal tip support. This information will become increasingly important in computational modeling of nasal tip mechanics and ultimately will enhance surgical planning for rhinoplasty.Level of evidenceNA
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Evaluation of Reported Malignant Transformation of Vestibular Schwannoma: De Novo and After Stereotactic Radiosurgery or Surgery.
ObjectiveTo critically analyze each reported case of malignant transformation of vestibular schwannoma (VS) after either stereotactic radiosurgery (SRS) or microsurgery (MS).Data sourcesWe searched the Pubmed/Medline database using the relevant key words vestibular schwannoma, acoustic neuroma, malignant, transformation, radiation, induced, stereotactic, radiosurgery, malignancy, GammaKnife, and CyberKnife and combinations thereof.Study selectionInclusion criteria for malignant transformation of VS after SRS included histopathology of initially benign VS, subsequent histopathology confirming malignant VS, reasonable latency period between malignancy and benign diagnoses.Data extractionA neurotologist and a skull base neurosurgeon independently assessed each case report for quality, entry, exclusion criteria, and comparability of extracted data.Data synthesisWe calculated median age, latency times, and survival times for each case report.ResultsMalignant transformation has been documented to occur after either SRS or MS. Eight cases were included that showed histopathologic evidence of malignant transformation after SRS and MS. Four cases of malignant transformation were included that demonstrated malignant transformation after MS only. Malignant transformation of VS can also occur de novo, and de novo malignant VSs are also encountered, which can confound a causal inference from either SRS or MS. Eighteen cases of primary malignant VS were included. Studies that were identified but not included in the review are summarized and tabulated. We found 12 studies of malignant transformation associated with NF2.ConclusionThe potential mechanism leading to malignant transformation of VS seems more obvious for SRS and is less understood for MS. Given a low incidence of de novo malignant schwannoma, the possibility that these are spontaneous events in either setting cannot be ruled out. Risk of malignant transformation of VS after either SRS or MS is not zero; however, the magnitude of this risk is probably minimal based on the evidence from eight histopathologically confirmed cases
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Evaluation of Reported Malignant Transformation of Vestibular Schwannoma: De Novo and After Stereotactic Radiosurgery or Surgery.
ObjectiveTo critically analyze each reported case of malignant transformation of vestibular schwannoma (VS) after either stereotactic radiosurgery (SRS) or microsurgery (MS).Data sourcesWe searched the Pubmed/Medline database using the relevant key words vestibular schwannoma, acoustic neuroma, malignant, transformation, radiation, induced, stereotactic, radiosurgery, malignancy, GammaKnife, and CyberKnife and combinations thereof.Study selectionInclusion criteria for malignant transformation of VS after SRS included histopathology of initially benign VS, subsequent histopathology confirming malignant VS, reasonable latency period between malignancy and benign diagnoses.Data extractionA neurotologist and a skull base neurosurgeon independently assessed each case report for quality, entry, exclusion criteria, and comparability of extracted data.Data synthesisWe calculated median age, latency times, and survival times for each case report.ResultsMalignant transformation has been documented to occur after either SRS or MS. Eight cases were included that showed histopathologic evidence of malignant transformation after SRS and MS. Four cases of malignant transformation were included that demonstrated malignant transformation after MS only. Malignant transformation of VS can also occur de novo, and de novo malignant VSs are also encountered, which can confound a causal inference from either SRS or MS. Eighteen cases of primary malignant VS were included. Studies that were identified but not included in the review are summarized and tabulated. We found 12 studies of malignant transformation associated with NF2.ConclusionThe potential mechanism leading to malignant transformation of VS seems more obvious for SRS and is less understood for MS. Given a low incidence of de novo malignant schwannoma, the possibility that these are spontaneous events in either setting cannot be ruled out. Risk of malignant transformation of VS after either SRS or MS is not zero; however, the magnitude of this risk is probably minimal based on the evidence from eight histopathologically confirmed cases
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Migraine features in patients with Meniere's disease.
Objectives/hypothesisTo better understand the features of migraine in Meniere's disease (MD).Study designRetrospective review of prospectively obtained surveys in an outpatient clinic of a tertiary medical center.MethodsDetailed questionnaires on headaches and dizziness were given to consecutive patients presenting with dizziness. The responses were verified by the clinician with the patient. The data, in addition to the clinical history and audiogram, were used to diagnose patients with migraine headaches and MD using criteria set by the International Headache Society (IHS) and the American Academy of Otolaryngology-Head and Neck Surgery, respectively. The prevalence of migraine-like symptoms in those patients with MD, who did not fit the diagnostic criteria for migraine, was evaluated.ResultsThirty-seven patients with definite MD were included. There was a predominance of females (female/male:26/11). Mean age of patients was 52 ± 14 years. Nineteen patients (51%) had migraine headaches. Fifteen patients fulfilled the criteria for definite vestibular migraine. Of those who did not fulfill the IHS migraine criteria, a majority had characteristics such as a family history of migraine, visual motion sensitivity, or lifelong motion sickness that were highly suggestive of a migraine disorder.ConclusionsA majority of patients with MD have migraine headaches as defined by the IHS. Sensitivity to visual motion, light and sound, head motion, smells, weather changes, or medication was present in 95% of all patients with definite MD and 82% of non-IHS migraine MD patients. This may suggest that MD may be an atypical variant of migraine
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Curved adjustable fiberoptic laser for endoscopic cholesteatoma surgery.
ObjectiveTo determine whether endoscopic cholesteatoma removal can be performed efficiently and safely using a curved fiberoptic-based laser.BackgroundAngled instruments are required in endoscopic ear surgery to access recesses of the middle ear without extra drilling. Lasers are effective at ablating visible and microscopic cholesteatoma matrix and removing granulation tissue.Study designRetrospective case review from 2006 to 2013.SettingSingle tertiary care center.PatientsPatients who underwent cholesteatoma surgery with otoendoscopy.InterventionResidual cholesteatoma that could not be reached by conventional microinstruments was identified using an endoscope. This residual cholesteatoma was ablated in a contactless manner using a fiberoptic-based curved laser carrier with an argon laser. The laser tip through the carrier probe has a 45-degree curve, and the length of the tip is adjustable, allowing it to be used in recesses or around corners, such as in the sinus tympani, around the stapes suprastructure, in the oval window, or in the Eustachian tube orifice.Main outcome measuresPresence or absence of residual cholesteatoma after laser ablation and complications.ResultsIn 7 cases, the fiberoptic curved laser was used to ablate cholesteatoma completely with no injury to surrounding structures and with no evidence of recidivism with a mean follow-up period of 19 months. There were no cases of sensorineural hearing loss or perilymphatic fistula.ConclusionThe curved laser probe allows for precise removal of cholesteatoma endoscopically
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Laser-Assisted Control of Epistaxis in Hereditary Hemorrhagic Telangiectasia: A Systematic Review.
Background and objectivesHereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease, causes recurrent mucous membrane hemorrhage, especially epistaxis. In this systematic review, we discuss the efficacies of the three most common laser photocoagulation treatments for HHT-related epistaxis.Study design/materials and methodsA systematic literature search was conducted in PubMed and MEDLINE from database inception to March 2019. Studies reporting epistaxis outcomes following argon, neodymium-doped yttrium aluminum garnet (Nd:YAG), and diode laser photocoagulation for HHT were included. χ2 and Barnard's exact tests were utilized to detect differences in reduced epistaxis frequency and intensity rates.ResultsFifteen out of 157 published studies met our eligibility criteria, spanning a collective 362 patients. Argon, Nd:YAG, and diode laser therapy reduced epistaxis frequency in 90.4%, 88.9%, and 71.1% of patients, respectively, and reduced epistaxis intensity in 87.8%, 87.2%, and 71.1% of patients, respectively. Diode laser photocoagulation significantly underperformed in both outcome measurements when compared with argon (frequency: P = 0.005; intensity: P = 0.034) and Nd:YAG (frequency: P = 0.012; intensity: P = 0.041). There was no significant difference between argon and Nd:YAG in reducing HHT epistaxis frequency (P = 0.434) or intensity (P = 0.969). Categorizing HHT patients by clinical severity demonstrated a higher rate of improvement in the mild-moderate group compared with the severe group in both argon (P < 0.001) and Nd:YAG (P < 0.001) therapeutic methods. While no significant differences were found in rates of improved epistaxis outcomes between argon and Nd:YAG in mild-moderate HHT patients (frequency: P = 0.061; intensity: P = 0.061), Nd:YAG demonstrated greater rates of reduction in epistaxis frequency (P = 0.040) and intensity (P = 0.028) than argon among severe HHT patients.ConclusionsHHT is a lifelong disease, plaguing patients with debilitating epistaxis. Intranasal laser photocoagulation of telangiectasias using argon or Nd:YAG laser therapy can yield improved epistaxis outcomes compared with diode laser photocoagulation. In severe cases of HHT, Nd:YAG laser therapy provides greater improvements in epistaxis outcomes than argon photocoagulation. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc