Publications by authors named "Hyung-ki Park"

The term "Juxtafacet cyst" refers to both synovial cysts and ganglion pseudocysts associated with the lumbar facet joint. As conservative treatment for the juxtafacet cyst has a minimal effect, complete excision through surgery is considered the first choice of treatment. In this study, we retrospectively reviewed the clinical outcomes of percutaneous epidural neuroplasty for symptomatic lumbar juxtafacet cysts.

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Further improving the corrosion resistance of the ASTM Grade 13 (Gr13) titanium alloy was achieved by manipulating the cathodic modification effect. The cathodic modification of Gr13 was mainly related to the TiNi precipitate, where minor Ru was contained and controlled the precipitate in terms of size and distribution, which could manipulate the cathodic modification effect. Parameters such as temperature and cooling rate during the recrystallization process were designed to control precipitation behavior, where the temperature at 850 °C was selected to allow the full dissolution of the TiNi precipitate.

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Objective: In March 2020, World Health Organization declared a global pandemic caused by a novel coronavirus (SARS-CoV-2). The disease caused by this virus is called COVID-19. Due to its high contagiousness, many changes have occurred in overall areas of our daily life including hospital use by patients.

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BACKGROUND We investigated the effects of the upper-body flexibility exercises on the golf performance of a female amateur golfer. CASE REPORT The participant was a 43-year-old woman who performed a general golf swing exercise (30 min) and an upper-body flexibility exercise (20 min) 3 times a week, for a total of 6 times in 2 weeks. The maximum rotation angle of the upper body was measured using a goniometer.

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Article Synopsis
  • Biologics are essential medications that help reduce illness and death, but access remains a challenge even in wealthy nations like the USA.
  • Misunderstandings about biosimilars, fueled by confusing terminology, hinder patients' access to these important treatments.
  • The paper aims to clarify the differences between biologics and the FDA's designation of interchangeability for biosimilars, underscoring the need for more education for both the public and stakeholders involved.
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Microstructures and corrosion properties of pure titanium were characterized when iron was used as a grain refiner. The added Fe element acted as a strong grain refiner for pure titanium by forming β Ti phase at grain boundaries, and 0.15 wt% Fe was revealed to be a sufficient amount to make the grain size of pure titanium below 20 μm, which was the requirement for the desired titanium cathode.

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Objective: People are living longer and the elderly population continues to increase. The incidence of degenerative spinal diseases (DSDs) in the elderly population is quite high. Therefore, we are facing more cases of DSD and offering more surgical solutions in geriatric patients.

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Objective: Spinal degeneration is a progressive disease, worsening over time. Lumbar degenerative disease (LDD) is a major spinal disease in elderly patients. Surgical treatment is considered for medically intractable patients with LDD and reoperation after primary surgery is not uncommon.

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We report 3 cases of arachnoid cysts (ACs) that completely disappeared after burr hole drainage, without cyst fenestration into the subarachnoid space or cystoperitoneal shunt. The first patient was a 21-year-old female with an AC of the right cerebral convexity, found incidentally. After endoscopic AC fenestration was performed, the patient complained of persistent headache.

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In this study, the sintering behaviors of Nb-6Mo-20Si-3Cr (at percentage) in situ composite powders were studied. The Nb alloy powder was fabricated by a hydrogenation-dehydrogenation method, and both the alloy ingot and powders consisted of two phases: An Nb metal phase and the α-NbSi phase. Consolidation of the alloy powders was performed at 1500, 1600, and 1700 °C using spark plasma sintering, and the microstructures and phases formed at various sintering temperatures were analyzed.

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Background: In South Korea, special legislation was introduced in December 2016 to limit residents' training time to a maximum of 80 hours per week. The aim of this study was to survey the current training system and environment of neurosurgical residents and to find ways to improve the quality of neurosurgical training.

Methods: The questionnaire survey included 373 neurosurgical residents at 66 training hospitals nationwide, who were members of the Korean Neurosurgical Society.

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Background: Calcium pyrophosphate dihydrate deposition disease (CPDD) is a rare disease in the temporomandibular joint (TMJ) space. It forms a calcified crystal mass and induces a limitation of joint movement.

Case Presentation: The calcified mass in our case was occupied in the left TMJ area and extended to the infratemporal and middle cranial fossa.

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Objective: The risk factors of reoperation after microdecompression (MD) for lumbar spinal stenosis (LSS) are unclear. In this study, we presented the outcomes of MD for degenerative LSS and investigated the risk factors associated with reoperation.

Methods: A retrospective review was conducted using the clinical records and radiographs of patients with LSS who underwent MD.

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Objective: A modified surgical technique of posterior cervical foramintomy called posterior cervical inclinatory foraminotomy (PCIF) was introduced in previous preliminary article. PCIF allows better preservation of facet joint and capsule than conventional techniques. The authors conducted a study to investigate long-term outcomes of PCIF.

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In this study, the piezoresistive properties of CNT (Carbon Nanotube)/EPDM composite are characterized for the applications of a flexible sensor. The CNT/EPDM composites were prepared by using a Brabender mixer with MWCNT (Multi-walled Carbon Nanotube) and organoclay. The static and quasi-dynamic voltage output responses of the composite sensor were also experimentally studied and were compared with those of a conventional foil strain gage.

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Article Synopsis
  • This study compares the effectiveness and safety of multisession versus single dose radiosurgery for treating metastatic brain tumors in 90 patients.
  • Patients receiving multisession radiosurgery had a slightly longer overall survival (16.0 months) and better tumor response rates (95.4%) compared to single dose radiosurgery (11.5 months and 90%).
  • Notably, the multisession approach resulted in significantly lower toxicity rates (4% vs. 18.1% in single dose), suggesting it may be more suitable for larger tumors or those in sensitive brain areas.
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The crowned dens syndrome (CDS), also known as periodontoid calcium pyrophosphate dehydrate crystal deposition disease, is typified clinically by severe cervical pain, neck stiffness and atlantoaxial synovial calcification which could be misdiagnosed as meningitis, epidural abscess, polymyalgia rheumatica, giant cell arthritis, rheumatoid arthritis, cervical spondylitis or metastatic spinal tumor. Crystalline deposition on cervical vertebrae is less well known disease entity and only a limited number of cases have been reported to date. Authors report a case of CDS and describe the clinical feature.

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Redundant Nerve Roots (RNRs) is an uncommon clinical condition characterized by a tortuous, serpentine, large and elongated nerve root of the cauda equina. To our knowledge, most cases of RNRs are associated with lumbar stenosis, and RNRs associated with lumbar disc herniation has not been reported until now. Here we present a rare case of unusual RNRs associated with lumbar disc herniation mimicking intradural disc herniation.

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Stereotactic radiosurgery (SR) represents an increasingly utilized modality in the treatment of intracranial and extracranial pathologies. Stereotactic spine radiosurgery (SSR) uses an alternative strategy to increase the probability of local control by delivering large cumulative doses of radiation therapy (RT) in only a few fractions. SSR in the treatment of intramedullary lesions remains in its infancy-this review summarizes the current literature regarding the use of SSR for treating intramedullary spinal lesions.

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Object: Some patients with severe brain swelling treated with decompressive craniectomy may develop hydrocephalus. Consequently, these patients require cranioplasty and a ventriculoperitoneal (VP) shunt to relieve the hydrocephalus. However, there is no consensus as to the timing of the cranioplasty and VP shunt placement in patients requiring both.

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Objective: Lumbar spine stenosis (LSS) can result in symptomatic compression of the neural elements, requiring surgical treatment if conservative management fails. Minimally invasive surgery has come to be more commonly used for the treatment of LSS. The current study describes outcomes of bilateral microdecompression by unilateral or bilateral laminotomy (BML) for degenerative LSS after a minimum follow-up period of 3 years and investigates factors that result in a poor outcome.

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Objective: The aim of this study was to compare the efficacy of indirect and combined bypass surgery for treatment of adult moyamoya disease (MMD). The definition of combined bypass surgery is a combination of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and indirect anastomosis. Development of collateral circulation after surgery was investigated.

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Crystalline silicon films on an inexpensive glass substrate are currently prepared by depositing an amorphous silicon film and then crystallizing it by excimer laser annealing, rapid thermal annealing, or metal-induced crystallization because crystalline silicon films cannot be directly deposited on glass at a low temperature. It was recently shown that by adding HCI gas in the hot-wire chemical vapor deposition (HWCVD) process, the crystalline silicon film can be directly deposited on a glass substrate without additional annealing. The electrical properties of silicon films prepared using a gas mixture of SiH4 and HCl in the HWCVD process could be further improved by controlling the initial structure, which was achieved by adjusting the delay time in deposition.

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Purpose: Anterior cervical spine operations (ACSO) are generally considered to be safe and effective, but the vertebral artery (VA) is at risk during the procedure. Because the consequences of VA injury can be catastrophic, properly managing a VA injury is very important. However, due to the rarity of these injuries, there is no agreed upon treatment strategy.

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Objectives: This study aimed to provide further insights into the indications for adjuvant therapeutic strategies via analysis of the sites of initial recurrence after resection of gallbladder cancer (GBC) and intrahepatic (IHC) and extrahepatic cholangiocarcinoma (EHC).

Methods: Patients with biliary tract cancer who underwent potentially curative resection were identified from the database. Sites of initial disease recurrence were categorized as locoregional or distant.

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