Browsing by Subject "Needles"

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    3D-Printed Microneedles Create Precise Perforations in Human Round Window Membrane in Situ.
    (Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 2020-02) Chiang, Harry; Yu, Michelle; Aksit, Aykut; Wang, Wenbin; Stern-Shavit, Sagit; Kysar, Jeffrey W; Lalwani, Anil K

    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 ± 14.6 (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.
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    ItemOpen Access
    Anatomical and Functional Consequences of Microneedle Perforation of Round Window Membrane.
    (Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 2020-02) Yu, Michelle; Arteaga, Daniel N; Aksit, Aykut; Chiang, Harry; Olson, Elizabeth S; Kysar, Jeffrey W; Lalwani, Anil K

    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 ± 29.0 μm by 34.5 ± 16.8 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.
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    ItemOpen Access
    Cardiac cell-integrated microneedle patch for treating myocardial infarction.
    (Science advances, 2018-11) Tang, Junnan; Wang, Jinqiang; Huang, Ke; Ye, Yanqi; Su, Teng; Qiao, Li; Hensley, Michael Taylor; Caranasos, Thomas George; Zhang, Jinying; Gu, Zhen; Cheng, Ke
    We engineered a microneedle patch integrated with cardiac stromal cells (MN-CSCs) for therapeutic heart regeneration after acute myocardial infarction (MI). To perform cell-based heart regeneration, cells are currently delivered to the heart via direct muscle injection, intravascular infusion, or transplantation of epicardial patches. The first two approaches suffer from poor cell retention, while epicardial patches integrate slowly with host myocardium. Here, we used polymeric MNs to create "channels" between host myocardium and therapeutic CSCs. These channels allow regenerative factors secreted by CSCs to be released into the injured myocardium to promote heart repair. In the rat MI model study, the application of the MN-CSC patch effectively augmented cardiac functions and enhanced angiomyogenesis. In the porcine MI model study, MN-CSC patch application was nontoxic and resulted in cardiac function protection. The MN system represents an innovative approach delivering therapeutic cells for heart regeneration.
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    ItemOpen Access
    Strategies to Aid Identification of Apheresis PowerFlow Ports: A Case Report.
    (Journal of emergency nursing, 2021-01) Gill, Janique C; Oakley, Darlene J; Onwuemene, Oluwatoyosi A

    Introduction

    The PowerFlow implantable apheresis intravenous port is a venous access device for therapeutic apheresis procedures. In this case review article, we identify key similarities and differences between apheresis PowerFlow ports and traditional ports. We also list strategies that emergency departments can implement to aid in correct port identification.

    Methods

    Using a case review format, we describe the clinical presentation of a 33-year-old female with neuromyelitis optica who was evaluated in the emergency department for an acute exacerbation. She had a history of outpatient apheresis procedures that made use of bilateral PowerFlow ports. Mistaken for a conventional port, the right PowerFlow port was accessed with a Huber needle rather than the appropriate catheter-over-needle device. On infusion of intravenous fluids, the patient experienced pain and swelling. Ultimately, the port malfunctioned and was eventually replaced.

    Results

    A subsequent root cause analysis identified opportunities for education and aids to improve port identification. To this end, strategies were implemented to appropriately identify the PowerFlow port using at least 2 of the following methods: (1) look in the patient's chart for record of an implantable apheresis intravenous port; (2) check the port identification card, bracelet, or keychain issued at insertion; (3) palpate the port to look for the rounded top and hollow concave entry point; and (4) use x-ray or fluoroscopy to identify radiopaque port markers.

    Conclusion

    When a patient with a history of apheresis procedures presents with an implanted port, steps should be taken to ensure correct identification and access.