• Journal of Sensor Science and Technology
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• 제19권6호
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• pp.449-455
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• 2010

Implantable middle ear hearing devices(IMEHDs) have being actively studied to overcome the problems of conventional hearing aids. Vibration transducer, an output devices of IMEHDs, is attached on the ossicular chain and transmits mechanical vibration to cochlea. This approach allows us to hear more clear sound because mechanical vibration is effective to transfer high frequency acoustics, but occurs some problems such as fatigue accumulation to ossicular chian and reduction of vibration displacement caused by mass loading effect. Recently, many studies for the round window stimulation are announced, because it does not cause such problems. It have been studied by older transducers designed for attaching on ossicular chain. In this paper, we proposed a new electromagnetic transducer which consists of two magnets, three coils and a vibration membrane. The magnet assembly, magnet coupled in opposite direction, were placed in the center of three coils, and the optimum length of each coil generating maximum vibrational force was calculated by finite element analysis(FEA). The transducer was implemented as the calculated length of each coil, and measured vibration displacement. From the results, it is verified the vibration displacement can be improved by optimizing the length of coils.

• The Korean Journal of Pain
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• 제27권2호
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• pp.139-144
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• 2014

Background: To manage intractable cancer pain, an alternative to systemic analgesics is neuraxial analgesia. In long-term treatment, intrathecal administration could provide a more satisfactory pain relief with lower doses of analgesics and fewer side-effects than that of epidural administration. However, implantable drug delivery systems using intrathecal pumps in Korea are very expensive. Considering cost-effectiveness, we performed epidural analgesia as an alternative to intrathecal analgesia. Methods: We retrospectively investigated the efficacy, side effects, and complications of epidural morphine and local anesthetic administration through epidural catheters connected to a subcutaneous injection port in 29 Korean terminal cancer patients. Patient demographic data, the duration of epidural administration, preoperative numerical pain rating scales (NRS), side effects and complications related to the epidural catheterization and the drugs, and the numerical pain rating scales on the 1st, 3rd, 7th and 30th postoperative days were determined from the medical records. Results: The average score for the numerical pain rating scales for the 29 patients decreased from $7{\pm}1.0$ at baseline to $3.6{\pm}1.4$ on postoperative day 1 (P < 0.001). A similar decrease in pain intensity was maintained for 30 days (P < 0.001). Nausea and vomiting were the most frequently reported side effects of the epidural analgesia and two patients (6.9%) experienced paresthesia. Conclusions: Epidural morphine and local anesthetic infusion with a subcutaneous pump seems to have an acceptable risk-benefit ratio and allows a high degree of autonomy to patients with cancer pain.

• Proceedings of the KOSOMBE Conference
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.273-276
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• 1996

In the Total Artificial Heart (TAH) and Ventricular Assist Device (VAD), the size implanting the internal controller into human body is very serious problem. Hence, we need the size reduction of that controller for safe implantation. Using PSD302 chip for microcontroller-based applications, we could decrease the number of components in the digital control board and miniaturize the digital control board. We could replace a ROM, RAM, and a latch with that single chip, so the size of the newly developed board could be half the previous board.

• Journal of Chest Surgery
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• 제34권4호
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• pp.296-304
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• 2001

배경: 이번 연구의 목적은 체내이식형 양심실 보조장치의 개발을 위한 안전하고 간편한 동물실험 모델을 확립하는 것이며 이동작동형 완전 인공심장의 양심실 보조장치로의 사용 가능성을 알아보는 것이다. 대상 및 방법: 7마리의 Corridale 양을 대상으로 실험하였다. 5번째 늑간극을 통하여 좌측 개흉술을 시행하고 좌측 유출로 캐뉼라는 하행 대동맥에 Dacron graft을 사용하여 연결하였고 유입로 캐뉼라는 좌심방에 삽입하였다. 우측 유출로 캐뉼라는 하행 대동맥과 같은 방법으로 주폐동맥에 연결하였으며 유입로 캐뉼라는 혜동맥을 하방으로 젖혀 우심방이를 노출시킨 다음 우심방이에 삽입하였다. 4마리에 있어서는 양심실 보조장치를 전복막강(preperitoneal space)에 위치시켰으며 2마리에 촤측흉강 내에, 1마리에서는 외부에 위치시켰다. aPTT는 수술전 aPTT의 2∼2.5배로 맞추어 주었다 결과: 수술중 또는 수술직후 사망한 경우는 없었으며 7마리 모두 인공호흡기 이탈이 가능하였고 스스로 기립하고 음식물 섭취도 가능하였다. 1마리는 술후 2일째 혈전 색전증 및 인공호흡기 작동 잘못으로 사망하였으며 2마리의 겨우는 술후 2일째 각각 양심실 보조장치의 작동 잘못 및 호흡부전으로 사망하였고, 3마리의 경우는 술후 4일째 혈전색전증으로 인한 급성신부전 및 호흡부전 등으로 사망하였다. 1마리에 있어서는 28일간 생존하였으며 양심실 보조장치의 구동 장치에 연결된 라인의 마로로 인해 양심실 보조장치의 작동이 정지되었으나 바로 양심실 보조장치를 제거하고 살릴 수 있었다. 모든 경우에 있는 캐뉼라를 삽입하고 양심실 보조장치를 작동시키는데 큰 어려움이 없었다. 7마리 중 4마리에서 혈전이 발견되었으며 특히 판막을 연결한 부위에 혈전생성이 많았다. 그러나 캐뉼라에는 혈전생성이 없었다. 결론: 양에 있어서 좌측 개흉술 및 전복막강 공간에 양심실 보조장치를 위치시키는 이번 동물실험 모델은 체내 이식형 양심실 보조장치 개발을 위한 좋은 동물실험 모델이라고 생각된다. 또한 디동 작동기형 완전 인공심장의 혈전생성을 억제할수 있는 방법들의 연구개발이 지속된다면 장기간의 체내 이식형 양심실 보조장치로 사용할 수 있을 것으로 생각된다.

• Journal of Veterinary Clinics
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• 제24권3호
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• pp.414-418
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• 2007

A 2.8-year-old intact female Beagle dog (weighing 11kg) was referred with the primary complaint of exercise intolerance with occasional syncope. Physical examination revealed irregularly irregular heart rhythm with persistent pulse deficits. The 12-lead surface ECG showed a third degree heart block. Permanent transvenous cardiac pacing with a bipolar implantable pacemaker was performed in the right ventricle. After pacemaker implantation, the dog did not show syncopal episode and is currently able to take a walk with an owner. No side effects associated with permanent pacemaker implantation has been observed to date.

• BioChip Journal
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• 제12권4호
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• pp.332-339
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• 2018

The future neuro-prosthetic devices would be required spikes data monitoring through sub-nanoscale transistors that enables to neuroscientists and clinicals for scalable, wireless and implantable applications. This research investigates the spikes monitoring through integrated CNT front-end amplifier for neuro-prosthetic diagnosis. The proposed carbon nanotube-based architecture consists of front-end amplifier (FEA), integrate fire neuron and pseudo resistor technique that observed high electrical performance through neural activity. A pseudo resistor technique ensures large input impedance for integrated FEA by compensating the input leakage current. While carbon nanotube based FEA provides low-voltage operation with directly impacts on the power consumption and also give detector size that demonstrates fidelity of the neural signals. The observed neural activity shows amplitude of spiking in terms of action potential up to $80{\mu}V$ while local field potentials up to 40 mV by using proposed architecture. This fully integrated architecture is implemented in Analog cadence virtuoso using design kit of CNT process. The fabricated chip consumes less power consumption of $2{\mu}W$ under the supply voltage of 0.7 V. The experimental and simulated results of the integrated FEA achieves $60G{\Omega}$ of input impedance and input referred noise of $8.5nv/{\sqrt{Hz}}$ over the wide bandwidth. Moreover, measured gain of the amplifier achieves 75 dB midband from range of 1 KHz to 35 KHz. The proposed research provides refreshing neural recording data through nanotube integrated circuit and which could be beneficial for the next generation neuroscientists.

• The Journal of the Korea institute of electronic communication sciences
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• 제14권3호
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• pp.619-626
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• 2019

The advances of semiconductor and circuitry technology dovetailed with nano processing techniques have further enhanced micro-miniaturization, sensitivity, longevity and reliability in MID(Medical Implant Device). Nevertheless, one of the remaining challenges is whether power can sufficiently and continuously be supplied for the operation of the MID. Self-powered MID that harvest biomechanical energy from human motion, respiratory and muscle movement are part of a paradigm shift. In this paper, we developed a rechargeable pacemaker through self-power generation with the triboelectric nanogenerator. We demonstrate a fully implanted pacemaker based on an implantable triboelectric nanogenerator, which act as a storage as well as active movement on a large-animal(dog) scale. The self-power pacemaker harvested from animal motion is 2.47V, which is higher than the required pacemaker device sensing voltage(1.35V).

• Journal of the Microelectronics and Packaging Society
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• 제28권2호
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• pp.13-28
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• 2021

Since transient electronic devices can operate under harsh conditions such as electrolytic solutions or inside the body, and be removed by hydrolysis after operation, they can replace conventional electronic devices in various research areas like biomedical implantable devices. Moreover, transient electronic devices that can dissolve in water and enzymes are the focus of the new concept of green technology, which can solve electrical waste issues. However, the surroundings of transient electronic devices can deteriorate internal device components. Thus, an encapsulation strategy is introduced for stable operation in solution by shielding the outside of a device with a passive barrier. This article summarizes recent research trends in transient electronic devices, including their background, dissolution behavior, and encapsulation strategies to enhance reliability by blocking water permeation.

• Journal of Biomedical Engineering Research
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• 제44권1호
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• pp.1-10
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• 2023

With the announcement of MEDICAL DEVICE REGULATION 2017/745 (MDR) on April 5 2017, medical device manufacturers shall apply ISO 14971:2019 (3^rd) revised in December 2019. However, there is not much related information and guidance available to medical device manufacturers, especially single use medical device. Risk management process basically follow 5 steps which are Risk Analysis, Risk Evaluation, Risk Control, Evaluation of overall residual risk and post-production activities. The purpose of this study is to provide a guidance of from risk analysis with Failure Mode and Effects Analysis (FMEA) table to overall residual risk evaluation for the single use medical device and to reflect it in a Periodic Safety Update Reports (PSUR) to satisfy with MDR requirements with single use medical device which are widely used and manufactured FDA class 2 or CE class IIb as examples. For this study, single use medical device manufacturer can adopt ISO 14971:2019 in accordance with MDR requirements and it can be extended to the PSUR. But there are still limitations to adopt to the all-single use medical device especially high class, private device and implantable device. So, Competent Authority (CA) shall publish more guidance for the single use medical device.

• Composites Research
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• 제21권3호
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• pp.18-23
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• 2008

The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, implantable Drug Delivery System (DDS) was fabricated by an RP system, Nano Composite Deposition System (NCDS). The DDS composite consists of 5-fluorouracil (5-FU), as drug particles, and PLGA85/15 as biodegradable polymer matrix. To have larger surface area, the DDS was fabricated in a scaffold shape, and its degradation was tested in vitro environment. Biocompatible Hydroxyapatite (HA) powders were added to the drug-polymer composite in order to control drug release. Test results showed a possibility of controlled release of scaffold DDS over 50 days.