Faculty Bibliography

Background/UNASSIGNED:Tranexamic acid (TXA) is an antifibrinolytic that has become widely used in aesthetic facial plastic surgery, although its efficacy has not been well investigated. Objectives/UNASSIGNED:To evaluate the existing evidence for use of TXA in aesthetic facial plastic surgery, highlighting routes of administration, dosing, surgical applications, and clinical outcomes. Methods/UNASSIGNED:Systematic review of primary literature evaluating TXA in aesthetic facial plastic surgery. Results/UNASSIGNED:Eleven studies met inclusion criteria: 8 prospective randomized controlled trials, 2 retrospective case series/cohort studies, and 1 clinical opinion. Six studies evaluated TXA in rhinoplasty, 4 in rhytidectomy, and 1 in blepharoplasty. Significant reductions in intraoperative blood loss were found in 5 rhinoplasty studies. Three rhinoplasty and 2 rhytidectomy studies found significantly reduced postoperative edema and ecchymosis. One rhinoplasty and 1 rhytidectomy study reported reduced operative time and time to achieve hemostasis. One rhytidectomy study reported reduced postoperative drain output and faster time to drain removal. No studies reported an adverse outcome directly related to TXA. Conclusions/UNASSIGNED:Existing literature investigating TXA in aesthetic facial plastic surgery is sparse with varying levels of evidence and heterogeneous data. Literature suggests systemic TXA reduces intraoperative blood loss during rhinoplasty, although the clinical significance of this blood loss reduction is unclear. TXA may also reduce postoperative edema and/or ecchymosis in rhytidectomy and rhinoplasty, although the lack of validated grading scales yields insufficient evidence to support this claim. Topical and subcutaneously injected TXA are emerging administration routes in rhytidectomy, with evidence suggesting TXA mixed with tumescent may reduce postoperative drain output, thereby expediting drain removal. Level of Evidence 2/UNASSIGNED/:

OBJECTIVES:Pitch is poorly perceived by cochlear implant (CI) users. However, as it is not well understood how pitch is encoded with electric stimulation, improving pitch representation with a CI is challenging. Changes in place of stimulation along the cochlea have been described as changes in pitch and can be accurately ranked by CI users. However, it remains unknown if place-pitch can be used to encode musical intervals, which are a necessary attribute of pitch. The objective of these experiments is to determine if place-pitch coding can be used to represent musical intervals with a CI. DESIGN:In the first experiment, 10 CI users and 10 normal hearing (NH) controls were tested on their sensitivity to changes in the semitone spacing between each of the notes in the melody "Happy Birthday." The changes were implemented by uniformly expanding or compressing the frequency differences between each note in the melody. The participant's task was to scale how "out-of-tune" the melody was for various semitone spacing distortions. The notes were represented by pure-tones ≥440 Hz to minimize potential useful temporal information from the stimuli. A second experiment replicated the first experiment using single-sided deafened CI users allowing for a within-subject control. A third experiment verified that the CI users who participated in Experiment 1 were each able to determine pitch direction reliably. RESULTS:Unlike NH listeners, CI listeners often ranked all distortions of interval spacing similarly in both the first and second experiment, and no effect of interval spacing was detected across CI users. Some participants found distorted interval spacings to be less out-of-tune than the nominally correct interval spacings. However, these patterns were inconsistent across listeners. Although performance was better for the NH listeners, the third experiment demonstrated that the CI listeners were able to reliably identify changes in pitch direction from place-pitch coding. CONCLUSIONS:The data suggest that place-pitch intervals are not properly represented through a CI sound processor. Some limited support is found for place-pitch being useful for interval encoding as some participants demonstrated improved ratings for certain interval distortions. Presumably the interval representation for these participants could be improved by a change to the frequencies represented by each electrode. However, as these patterns vary across listeners, there is not a universal correction to frequency representation that will solve this issue. As results are similar for single-sided deafened CI users, the limitations in ratings are likely not limited by an eroded representation of the melody caused by an extended duration of deafness.

OBJECTIVES:There are many potential advantages to combined electric and acoustic stimulation (EAS) with a cochlear implant (CI), including benefits for hearing in noise, localization, frequency selectivity, and music enjoyment. However, performance on these outcome measures is variable, and the residual acoustic hearing may not be beneficial for all patients. As such, we propose a measure of spectral resolution that might be more predictive of the usefulness of the residual hearing than the audiogram alone. In the following experiments, we measured performance on spectral resolution and speech perception tasks in individuals with normal hearing (NH) using low-pass filters to simulate steeply sloping audiograms of typical EAS candidates and compared it with performance on these tasks for individuals with sensorineural hearing loss with similar audiometric configurations. Because listeners with NH had similar levels of audibility and bandwidth to listeners with hearing loss, differences between the groups could be attributed to distortions due to hearing loss. DESIGN:Listeners with NH (n = 12) and those with hearing loss (n = 23) with steeply sloping audiograms participated in this study. The group with hearing loss consisted of 7 EAS users, 14 hearing aid users, and 3 who did not use amplification in the test ear. Spectral resolution was measured with the spectral-temporal modulated ripple test (SMRT), and speech perception was measured with AzBio sentences in quiet and noise. Listeners with NH listened to stimuli through low-pass filters and at two levels (40 and 60 dBA) to simulate low and high audibility. Listeners with hearing loss listened to SMRT stimuli unaided at their most comfortable listening level and speech stimuli at 60 dBA. RESULTS:Results suggest that performance with SMRT is significantly worse for listeners with hearing loss than for listeners with NH and is not related to audibility. Performance on the speech perception task declined with decreasing frequency information for both listeners with NH and hearing loss. Significant correlations were observed between speech perception, SMRT scores, and mid-frequency audiometric thresholds for listeners with hearing loss. CONCLUSIONS:NH simulations describe a "best case scenario" for hearing loss where audibility is the only deficit. For listeners with hearing loss, the likely broadening of auditory filters, loss of cochlear nonlinearities, and possible cochlear dead regions may have contributed to distorted spectral resolution and thus deviations from the NH simulations. Measures of spectral resolution may capture an aspect of hearing loss not evident from the audiogram and be a useful tool for assessing the contributions of residual hearing post-cochlear implantation.

OBJECTIVE:To address variance in clinical care surrounding sporadic vestibular schwannoma, a modified Delphi study was performed to establish a general framework to approach vestibular schwannoma care. A multidisciplinary panel of experts was established with deliberate representation from key stakeholder societies. External validity of the final statements was assessed through an online survey of registered attendees of the 8th Quadrennial International Conference on Vestibular Schwannoma. STUDY DESIGN/METHODS:Modified Delphi method. METHODS:The panel consisted of 16 vestibular schwannoma experts (8 neurotology and 8 neurosurgery) and included delegates representing the AAOHNSF, AANS/CNS tumor section, ISRS, and NASBS. The modified Delphi method encompassed a four-step process, comprised of one prevoting round to establish a list of focus areas and three subsequent voting rounds to successively refine individual statements and establish levels of consensus. Thresholds for achieving moderate consensus, at ≥67% agreement, and strong consensus, at ≥80% agreement, were determined a priori. All voting was performed anonymously via the Qualtrics online survey tool and full participation from all panel members was required before procession to the next voting round. RESULTS:Through the Delphi process, 103 items were developed encompassing hearing preservation (N = 49), tumor control and imaging surveillance (N = 20), preferred treatment (N = 24), operative considerations (N = 4), and complications (N = 6). As a result of item refinement, moderate (4%) or strong (96%) consensus was achieved in all 103 final statements. Seventy-nine conference registrants participated in the online survey to assess external validity. Among these survey respondents, moderate (N = 21, 20%) or strong (N = 73, 71%) consensus was achieved in 94 of 103 (91%) statements, and no consensus was reached in 9 (9%). Of the four items with moderate consensus by the expert panel, one had moderate consensus by the conference participants and three had no consensus. CONCLUSION/CONCLUSIONS:This modified Delphi study on sporadic vestibular schwannoma codifies 100% consensus within a multidisciplinary expert panel and is further supported by 91% consensus among an external group of clinicians who regularly provide care for patients with vestibular schwannoma. These final 103 statements address clinically pragmatic items that have direct application to everyday patient care. This document is not intended to define standard of care or drive insurance reimbursement, but rather to provide a general framework to approach vestibular schwannoma care for providers and patients.

Advances in free flap reconstruction of complex head and neck defects have allowed for improved outcomes in the management of head and neck cancer. Technical refinements have decreased flap loss rate to less than 4%. However, the potential for flap failure exists at multiple levels, ranging from flap harvest and inset to pedicle lay and postoperative patient and positioning factors. While conventional methods of free flap monitoring (reliant on physical examination) remain the most frequently used, additional adjunctive methods have been developed. Herein we describe the various modalities of both invasive and noninvasive free flap monitoring available to date. Still, further prospective studies are needed to compare the various invasive and noninvasive technologies and to propel innovations to support the early recognition of vascular compromise with the goal of even greater rates of flap salvage.

Decellularized extracellular matrix (ECM) scaffolds derived from tissues and organs are complex biomaterials used in clinical and research applications. A number of decellularization protocols have been described for ECM biomaterials derivation, each adapted to a particular tissue and use, restricting comparisons among materials. One of the major sources of variability in ECM products comes from the tissue source and animal age. Although this variability could be minimized using established tissue sources, other sources arise from the decellularization process itself. Overall, current protocols require manual work and are poorly standardized with regard to the choice of reagents, the order by which they are added, and exposure times. The combination of these factors adds variability affecting the uniformity of the final product between batches. Furthermore, each protocol needs to be optimized for each tissue and tissue source making tissue-to-tissue comparisons difficult. Automation and standardization of ECM scaffold development constitute a significant improvement to current biomanufacturing techniques but remains poorly explored. This study aimed to develop a biofabrication method for fast and automated derivation of raw material for ECM hydrogel production while preserving ECM composition and controlling lot-to-lot variability. The main result was a closed semibatch bioreactor system with automated dosing of decellularization reagents capable of deriving ECM material from pretreated soft tissues. The ECM was further processed into hydrogels to demonstrate gelation and cytocompatibility. This work presents a versatile, scalable, and automated platform for the rapid production of ECM scaffolds.