The evolution of facial reanimation techniques.

This review article provides an updated discussion on evidence-based practices related to the evaluation and management of facial paralysis. Ultimately, the goals of facial reanimation include obtaining facial symmetry at rest, providing corneal protection, restoring smile symmetry and facial movement for functional and aesthetic purposes. The treatment of facial nerve injury is highly individualized, especially given the wide heterogeneity regarding the degree of initial neuronal insult and eventual functional outcome. Recent advancements in facial reanimation techniques have better equipped clinicians to approach challenging patient scenarios with reliable, effective strategies. We discuss how technology such as machine learning software has revolutionized pre- and post-intervention assessments and provide an overview of current controversies including timing of intervention, choice of donor nerve, and management of nonflaccid facial palsy with synkinesis. We highlight novel considerations to mainstay conservative management strategies and examine innovations in modern surgical techniques with a focus on gracilis free muscle transfer. Innervation sources, procedural staging, coaptation patterns, and multi-vector and multi-muscle paddle design are modifications that have significantly evolved over the past decade.

Nasal airway obstruction in patients with cleft lip nasal deformity: A systematic review.

BACKGROUND: Cleft lip nasal deformity (CLND)-associated nasal airway obstruction (CL-NAO) may be inadequately characterized, with its functional implications subsequently underappreciated and neglected. The purpose of this systematic review is to (1) summarize the available assessment results in CL-NAO, (2) evaluate the reliability of current assessment tools, and (3) identify ongoing gaps and inconsistencies for future study. METHODS: A systematic search of the MEDLINE, EMBASE, and Scopus databases was performed for articles studying CL-NAO. Articles focusing on noncleft populations or surgical techniques were excluded. Extracted data included information about study design, patient demographics, medical history, and assessment scores. RESULTS: Twenty-six articles met criteria for inclusion. Assessments included patient-reported outcome measures (PROMs), anatomic characterizations of CLND, and nasal airflow and resistance studies. Objective assessments were generally more reliable than subjective assessments in CLND. Unilateral CLND was better represented in the literature than bilateral CLND. For unilateral CLND, the cleft side was more obstructed than the noncleft side, with stereotyped patterns of anterior nasal deformity but varied middle and posterior deformity patterns. Overall, there was considerable heterogeneity in study design regarding stratification of CLND cohorts by age, cleft phenotype and laterality, and surgical history. CONCLUSIONS: A wide range of subjective and objective assessment tools were used to characterize CL-NAO, including PROMs, anatomic measurements, and airflow and resistance metrics. Overall, objective assessments of CL-NAO were more reliable than subjective surveys, which may have resulted from variable expectations regarding nasal patency in the CLND population combined with large heterogeneity in study design.

Challenges in the Management of Symptomatic Fallopian Canal Meningoceles: A Multicenter Case Series and Literature Review.

OBJECTIVE: To describe the presentations, the diagnosis, our treatment approaches, and the outcomes for 11 patients with fallopian canal meningocele (FCM). STUDY DESIGN MULTICENTER: Retrospective case series. SETTING: Tertiary referral centers. PATIENTS: Patients (N = 11) with radiographically or intraoperatively identified, symptomatic FCM. INTERVENTIONS: Surgical repair of cerebrospinal fluid (CSF) leak and meningocele versus observation. MAIN OUTCOME MEASURES: Presentation (including symptoms, radiographic imaging, and comorbidities), management (including surgical approach, technique for packing, use of lumbar drain), clinical outcomes (control of CSF leak, meningitis, facial nerve function), and revision surgery. RESULTS: Patients presented with spontaneous CSF leak (n = 7), conductive (N = 11) and sensorineural hearing loss (n = 3), nonpositional intermittent vertigo (n = 3), headaches (n = 4), and recurrent meningitis (n = 1). Risk factors in our series included obesity (n = 4), Chiari 1 malformation (n = 1), and head trauma (n = 2). Noncontrast computed tomography of the temporal bone and magnetic resonance imaging were positive for FCM in 10 patients. Eight patients were managed surgically via a transmastoid approach (n = 4), combined transmastoid and middle fossa (N = 3), or middle fossa alone (n = 1); three were managed conservatively with observation. Postoperative complications included worsened facial nerve palsy (n = 1), recurrent meningitis (n = 1), and persistent CSF leak that necessitated revision (n = 1). CONCLUSIONS: Facial nerve meningoceles are rare with variable presentation, often including CSF otorrhea. Management can be challenging and guided by symptomatology and comorbidities. Risk factors for FCM include obesity and head trauma, and Chiari 1 malformation may present with nonspecific otologic symptoms, in some cases, meningitis and facial palsy. Layered surgical repair leads to high rates of success; however, this may be complicated by worsening facial palsy.

Olfactory drug delivery with intranasal sprays after nasal midvault reconstruction.

Conductive olfaction and nose to brain drug delivery are important processes that remain limited by inadequate odorant or drug delivery to the olfactory airspace. Primary challenges include anatomic barriers and poor targeting to the olfactory region. This study uses computational fluid dynamics to investigate the effects of nasal midvault surgery on olfactory drug delivery with intranasal sprays. Soft tissue elevation, spreader flaps, and spreader grafts were performed on two fresh cadaveric specimens, using computed tomography for airway reconstruction. Nasal airflow and drug particle transport simulations were performed under these conditions: inhalation rate (15, 30 L/min), spray velocity (1, 5, 10 m/s), spray location (top, bottom, center, medial, lateral), head position (upright, supine, forward, backward), and particle size (1-100 µm). Simulation results were used to calculate drug particle deposition to the olfactory airspaces and bulbs. Total olfactory deposition was < 5% but attained a maximum of 36.33% when sorted by particle size. There was no association between nasal midvault surgery and olfactory deposition. No single parameter or technique demonstrated superior olfactory deposition, but smaller particle size, slower spray velocity, and higher inhalation rate tended to optimize olfactory deposition, providing important implications for future intranasal spray and drug design to target the olfactory airspace.

Characterizing Olfactory Dysfunction in Patients with Unilateral Cleft Lip Nasal Deformities.

Background: Unilateral cleft lip nasal deformity (uCLND) is associated with olfactory dysfunction, but the underlying etiology remains poorly understood. Objective: To investigate the etiology of uCLND-associated olfactory dysfunction using clinical, computational, and histologic assessments. Methods: Inclusion criteria: uCLND patients >16 years undergoing septorhinoplasty. Exclusion criteria: prior septoplasty or rhinoplasty, pregnancy, sinusitis. Measured outcomes: patient-reported scores, rhinomanometry, smell identification and threshold tests, computational fluid dynamics (CFD) airflow simulations, and histologic analysis of olfactory epithelium. Results: Five uCLND subjects were included: 18-23 years, three male and two female, four left-sided cleft and one right-sided cleft. All subjects reported moderate to severe nasal obstruction. Smell identification and threshold tests showed varying degrees of hyposmia. Nasal resistance was higher on the cleft side versus noncleft side measured by rhinomanometry (median 3.85 Pa-s/mL, interquartile range [IQR] = 21.96, versus 0.90 Pa-s/mL, IQR = 5.17) and CFD (median 1.04 Pa-s/mL, IQR = 0.94 vs. 0.11 Pa-s/mL, IQR = 0.12). Unilateral olfaction varied widely and was dependent on unilateral percentage olfactory airflow. Biopsies revealed intact olfactory neuroepithelium. Conclusions: uCLND-associated olfactory dysfunction appears to be primarily conductive in etiology and highly susceptible to variations in nasal anatomy. Clinical Trial Registration number: NCT04150783.

Systematic Review of Otologic and Neurotologic Surgery Using the 3-dimensional Exoscope.

Objective: The 3D exoscope is an emerging technology that has been met with success in neurosurgery and is now increasingly used in otologic and neurotologic surgery. There is currently no consensus on its safety, efficiency, and utility, compared to the traditional microscope for these procedures. This systematic review aims to evaluate the use of the 3-dimensional (3D) exoscope for otologic and neurotologic surgery. Databases Reviewed: MEDLINE/PubMed, Web of Science, Scopus, and EMBASE. Methods: A systematic search of the databases was conducted for otologic and neurotologic surgery using the 3D exoscope. English language papers with no limit on the date of publication were considered. Inclusion criteria: full articles studying otologic or neurotologic/skull base surgery using exoscopes. Exclusion criteria: non-otologic surgery and non-neurotologic/skull base surgery, exclusive use of the traditional microscope, editorials, video reports, and letters. Two authors independently reviewed papers for inclusion; discrepancies were settled by consensus. Extracted variables included: number of patients, types of surgical procedures, operative and postoperative complications, setup and operative time, and visualization and ergonomic rating. Results: Six articles containing 128 surgical cases (103 exoscopic and 25 microscopic) were analyzed. Of the exoscopic cases, 21% were surgeries for chronic ear disease, 5% were cochlear implants, and 74% were lateral skull base procedures encompassing a wide variety of approaches. Conclusion: Based on preliminary studies, the exoscope appears to be comparable in safety, visualization, and efficiency compared to the operating microscope, with the potential for increased comfort and ease of use.

Inner ear delivery: Challenges and opportunities.

OBJECTIVES: The treatment of inner ear disorders remains challenging due to anatomic barriers intrinsic to the bony labyrinth. The purpose of this review is to highlight recent advances and strategies for overcoming these barriers and to discuss promising future avenues for investigation. DATA SOURCES: The databases used were PubMed, EMBASE, and Web of Science. RESULTS: Although some studies aimed to improve systemic delivery using nanoparticle systems, the majority enhanced local delivery using hydrogels, nanoparticles, and microneedles. Developments in direct intracochlear delivery include intracochlear injection and intracochlear implants. CONCLUSIONS: In the absence of a systemic drug that targets only the inner ear, the best alternative is local delivery that harnesses a combination of new strategies to overcome anatomic barriers. The combination of microneedle technology with hydrogel and nanoparticle delivery is a promising area for future investigation. LEVEL OF EVIDENCE: NA.

Anatomical and Functional Consequences of Microneedle Perforation of Round Window Membrane.

HYPOTHESIS: Microneedles can create microperforations in the round window membrane (RWM) without causing anatomic or physiologic damage. BACKGROUND: Reliable delivery of agents into the inner ear for therapeutic and diagnostic purposes remains a challenge. Our novel approach employs microneedles to facilitate intracochlear access via the RWM. This study investigates the anatomical and functional consequences of microneedle perforations in guinea pig RWMs in vivo. METHODS: Single three-dimensional-printed, 100 µm diameter microneedles were used to perforate the guinea pig RWM via the postauricular sulcus. Hearing was assessed both before and after microneedle perforation using compound action potential and distortion product otoacoustic emissions. Confocal microscopy was used ex vivo to examine harvested RWMs, measuring the size, shape, and location of perforations and documenting healing at 0 hours (n = 7), 24 hours (n = 6), 48 hours (n = 6), and 1 week (n = 6). RESULTS: Microneedles create precise and accurate perforations measuring 93.1 ±â€Š29.0 µm by 34.5 ±â€Š16.8 µm and produce a high-frequency threshold shift that disappears after 24 hours. Examination of perforations over time demonstrates healing progression over 24 to 48 hours and complete perforation closure by 1 week. CONCLUSION: Microneedles can create a temporary microperforation in the RWM without causing significant anatomic or physiologic dysfunction. Microneedles have the potential to mediate safe and effective intracochlear access for diagnosis and treatment of inner ear disease.

3D-Printed Microneedles Create Precise Perforations in Human Round Window Membrane in Situ.

HYPOTHESIS: Three-dimensional (3D)-printed microneedles can create precise holes on the scale of micrometers in the human round window membrane (HRWM). BACKGROUND: An intact round window membrane is a barrier to delivery of therapeutic and diagnostic agents into the inner ear. Microperforation of the guinea pig round window membrane has been shown to overcome this barrier by enhancing diffusion 35-fold. In humans, the challenge is to design a microneedle that can precisely perforate the thicker HRWM without damage. METHODS: Based on the thickness and mechanical properties of the HRWM, two microneedle designs were 3D-printed to perforate the HRWM from fresh frozen temporal bones in situ (n = 18 total perforations), simultaneously measuring force and displacement. Perforations were analyzed using confocal microscopy; microneedles were examined for deformity using scanning electron microscopy. RESULTS: HRWM thickness was determined to be 60.1 ±â€Š14.6 (SD) µm. Microneedles separated the collagen fibers and created slit-shaped perforations with the major axis equal to the microneedle shaft diameter. Microneedles needed to be displaced only minimally after making initial contact with the RWM to create a complete perforation, thus avoiding damage to intracochlear structures. The microneedles were durable and intact after use. CONCLUSION: 3D-printed microneedles can create precise perforations in the HRWM without damaging intracochlear structures. As such, they have many potential applications ranging from aspiration of cochlear fluids using a lumenized needle for diagnosis and creating portals for therapeutic delivery into the inner ear.

Molecular mechanics and dynamics characterization of an in silico mutated protein: a stand-alone lab module or support activity for in vivo and in vitro analyses of targeted proteins.

Over the past 20 years, the biological sciences have increasingly incorporated chemistry, physics, computer science, and mathematics to aid in the development and use of mathematical models. Such combined approaches have been used to address problems from protein structure-function relationships to the workings of complex biological systems. Computer simulations of molecular events can now be accomplished quickly and with standard computer technology. Also, simulation software is freely available for most computing platforms, and online support for the novice user is ample. We have therefore created a molecular dynamics laboratory module to enhance undergraduate student understanding of molecular events underlying organismal phenotype. This module builds on a previously described project in which students use site-directed mutagenesis to investigate functions of conserved sequence features in members of a eukaryotic protein kinase family. In this report, we detail the laboratory activities of a MD module that provide a complement to phenotypic outcomes by providing a hypothesis-driven and quantifiable measure of predicted structural changes caused by targeted mutations. We also present examples of analyses students may perform. These laboratory activities can be integrated with genetics or biochemistry experiments as described, but could also be used independently in any course that would benefit from a quantitative approach to protein structure-function relationships.