Faculty Bibliography

OBJECTIVES/HYPOTHESIS:To evaluate the increase in access to the maxillary sinus (MS) with transnasal endoscopic medial maxillary sinus wall transposition (TEMMT), while preserving major structures of the nasal cavity. STUDY DESIGN:The study was divided into three parts: anatomical, radiographic, and case series. METHODS:Three cadaveric dissections (total of six sides) confirmed the feasibility of the TEMMT approach. Radiographic measurements using maxillofacial computed tomography scans were taken to assess the maximal antrostomy. The TEMMT approach was performed on six consecutive patients with benign MS disease. RESULTS:The cadaveric measurements were consistent with the radiographic measurements, which confirmed the maximum access to the MS. The radiographic measurements ranged from 14.4 to 39.1 mm in the anteroposterior dimension, 8.2 to 23.7 mm in the superior-inferior dimension, and 36° to 98° in the angle between the medial and anterior wall of the MS. In the patient series, five patients presented with an odontogenic cyst, and one patient had an antrochoanal polyp in the MS. The TEMMT approach provided excellent access and adequate resection, as well as preservation of the nasolacrimal duct and inferior turbinate. Finally, the mucosal flap was sufficient to cover the inferior meatal antrostomy. CONCLUSIONS:TEMMT provides excellent access into the MS, especially the floor and anterior wall, without the morbidities of the Caldwell-Luc or medial maxillectomy approach. In addition, the transposition of the inferior turbinate and the mucosal flap provides coverage of the medial wall with preservation of the inferior meatus, inferior turbinate, and nasolacrimal duct for patients with benign MS disease. LEVEL OF EVIDENCE:NA Laryngoscope, 126:1504-1509, 2016.

OBJECTIVES/OBJECTIVE:To investigate the effect of high flow nasal cannula oxygen therapy (HFOT) on middle ear pressure. MATERIALS/METHODS/METHODS:Ten patients (eight males and two females) with oxygen desaturations requiring HFOT were recruited with 19 ears available for our study. The study group was aged 29-90years (mean 65.3±16.5). All patients underwent a review of medical history, questioned about subjective hearing loss and underwent a standard otologic exam, with middle ear pressures measured with a GSI TympStar tympanometer. RESULTS:The middle ear peak pressures in our study group ranged from 25 to -200daPa (mean -13.7±56.3daPa). Volume of HFOT was delivered at 20-40L (mean 30.5±9L) and fraction of inspired oxygen required was 30-70% (mean 58±13%). There was a positive correlation between liters of oxygen delivery and middle ear pressure with a Pearson coefficient (R) of 0.436, although lacking statistical significance (p=0.06). CONCLUSION/CONCLUSIONS:Previous studies have shown that HFOT delivered in the range of 35-40L/min produces pharyngeal pressures at or above 5cm H2O. Since pharyngeal pressures of 5cm H2O produced via CPAP have shown to produce middle ear pressures above 40daPa, we expected HFOT to result in similar middle ear pressures of 35-40L/min. However, although our results show an increase in middle ear pressures with flow volume, HFOT did not produce significant increases in middle ear pressures. This may make HFOT an appropriate option of oxygen delivery to patients who require otologic procedures.

BACKGROUND:Lepidopterism refers to the manifestations of contact from any number of moths, butterflies, and caterpillars. Various symptoms have been described, ranging from localized skin irritation to systemic anaphylactic reactions. CASE REPORT/METHODS:We present a case of airway edema in an 8-month-old child from oral exposure to Woolly Bear Caterpillar (Pyrrharctia Isabella). After prompt emergency department recognition, her symptoms necessitated urgent operating room management by a team of otolaryngologists and close monitoring in a pediatric intensive care unit. A similar presentation in this species has not been described previously in the English literature. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Leptidopterism is rare, but recognition by the emergency practitioner is necessary for prompt and appropriate treatment. Rapid identification by the emergency physician of oral exposure and careful spine removal can be lifesaving in cases of significant oropharyngeal edema.

Conjugal transfer of chromosomal DNA between strains of Mycobacterium smegmatis occurs by a novel mechanism. In a transposon mutagenesis screen, three transfer-defective insertions were mapped to the lsr2 gene of the donor strain mc(2)155. Because lsr2 encodes a nonspecific DNA-binding protein, mutations of lsr2 give rise to a variety of phenotypes, including an inability to form biofilms. In this study, we show that efficient DNA transfer between strains of M. smegmatis occurs in a mixed biofilm and that the process requires expression of lsr2 in the donor but not in the recipient strain. Testing cells from different strata of standing cultures showed that transfer occurred predominantly at the biofilm air-liquid interface, as other strata containing higher cell densities produced very few transconjugants. These data suggest that the biofilm plays a role beyond mere facilitation of cell-cell contact. Surprisingly, we found that under standard assay conditions the recipient strain does not form a biofilm. Taking these results together, we conclude that for transfer to occur, the recipient strain is actively recruited into the biofilm. In support of this idea, we show that donor and recipient cells are present in almost equal numbers in biofilms that produce transconjugants. Our demonstration of genetic exchange between mycobacteria in a mixed biofilm suggests that conjugation occurs in the environment. Since biofilms are considered to be the predominant natural microhabitat for bacteria, our finding emphasizes the importance of studying biological and physical processes that occur between cells in mixed biofilms.

We have previously described a novel conjugal DNA transfer process that occurs in Mycobacterium smegmatis. To identify donor genes required for transfer, we have performed a transposon mutagenesis screen; we report here that LpqM, a putative lipoprotein-metalloproteinase, is essential for efficient DNA transfer. Bioinformatic analyses predict that LpqM contains a signal peptide necessary for the protein's targeting to the cell envelope and a metal ion binding motif, the likely catalytic site for protease activity. Using targeted mutagenesis, we demonstrate that each of these motifs is necessary for DNA transfer and that LpqM is located in the cell envelope. The requirement for transfer is specific to the donor strain; an lpqM knockout mutant in the recipient is still proficient in transfer assays. The activity of LpqM is conserved among mycobacteria; homologues from both Mycobacterium tuberculosis and Mycobacterium avium can complement lpqM donor mutants, suggesting that the homologues recognize and process similar proteins. Lipoproteins constitute a significant proportion of the mycobacterial cell wall, but despite their abundance, very few have been assigned an activity. We discuss the potential role of LpqM in DNA transfer and the implications of the conservation of LpqM activity in M. tuberculosis.