Publications by authors named "Chun Kee Chung"

Oblique lumbar interbody fusion (OLIF) is a minimally invasive lateral lumbar fusion technique and patients are discharged 1-2 days after surgery. Because OLIF utilizes a retroperitoneal approach close to the superior hypogastric plexus, postoperative urinary retention (POUR) may not be an uncommon problem. The purpose of this study was to present the incidence and outcomes of POUR with a systematic care protocol.

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  • The study focuses on chordoma, a rare and aggressive tumor of the cervical spine, highlighting its resistance to standard treatments and the necessity of surgical intervention.
  • Conducted across 7 medical centers, the research analyzes data from 45 patients over a median of 52 months, tracking local recurrence and survival outcomes.
  • Results show that while age significantly influences mortality rates, the method of tumor removal and additional treatments do not have a considerable impact on controlling the disease or improving survival rates.
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Background: Patients undergo regular clinical follow-up after laminoplasty for cervical myelopathy. However, those whose symptoms significantly improve and remain stable do not need to conform to a regular follow-up schedule. Based on the 1-year postoperative outcomes, we aimed to use a machine-learning (ML) algorithm to predict 2-year postoperative outcomes.

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  • The study evaluated the effectiveness of the Erector Spinae Plane Block (ESPB) for improving postoperative quality of recovery (QoR) in patients undergoing transforaminal lumbar interbody fusion (TLIF) or oblique lumbar interbody fusion (OLIF).
  • Patients were divided into two groups: one receiving ESPB and the other as a control, with QoR measured before surgery and on days 1 and 3 after surgery.
  • Results showed no significant difference in QoR-15 scores between the groups, but the ESPB group reported lower pain scores during ambulation and ambulated sooner after surgery, indicating some benefits in pain management rather than overall recovery quality.
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Focal cortical dysplasia type I (FCD I) is the most common cause of pharmaco-resistant epilepsy with the poorest prognosis. To understand the epileptogenic mechanisms of FCD I, we obtained tissue resected from patients with FCD I epilepsy, and from tumor patients as control. Using whole-cell patch clamp in acute human brain slices, we investigated the cellular properties of fast-spiking interneurons (FSINs) and pyramidal neurons (PNs) within the ictal onset zone.

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This study investigates the complex relationship between upper limb movement direction and macroscopic neural signals in the brain, which is critical for understanding brain-computer interfaces (BCI). Conventional BCI research has primarily focused on a local area, such as the contralateral primary motor cortex (M1), relying on the population-based decoding method with microelectrode arrays. In contrast, macroscopic approaches such as electroencephalography (EEG) and magnetoencephalography (MEG) utilize numerous electrodes to cover broader brain regions.

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Dual-position oblique lumbar interbody fusion with fluoroscopy (D-OLIF) requires repositioning the patient to a prone position for pedicle screw insertion. Recently, single-position surgery with navigation has been introduced. However, there are concerns regarding pedicle screw accuracy and achieving appropriate sagittal balance in single-position OLIF with navigation (S-OLIF).

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  • Encoding artificial perceptions via brain stimulation, especially for complex functions like speech perception, is a major challenge for brain-computer interfaces (BCI).* -
  • While electrical stimulation has successfully mapped and treated various neurological disorders, the application of this technology for inducing artificial speech perception is still largely underexplored.* -
  • The paper reviews different stimulation techniques, target brain areas for speech-like information, and potential strategies to overcome challenges in speech encoding.*
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Background And Objectives: In cases where dumbbell-shaped cervical schwannoma encases the vertebral artery (VA), there is a risk of VA injury during surgery. The objective of this study is to propose a strategy for preserving the VA during the surgical excision of tumors adjacent to the VA through the utilization of anatomic layers.

Methods: A retrospective analysis was conducted on 37 patients who underwent surgery for dumbbell-shaped cervical schwannoma with contacting VA from January 2004 to July 2023.

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Recent advancements in brain-computer interface (BCI) technology have seen a significant shift towards incorporating complex decoding models such as deep neural networks (DNNs) to enhance performance. These models are particularly crucial for sophisticated tasks such as regression for decoding arbitrary movements. However, these BCI models trained and tested on individual data often face challenges with limited performance and generalizability across different subjects.

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  • The study examined trends in degenerative lumbar spinal surgeries in South Korea during the first year of the COVID-19 pandemic, focusing on three epidemic waves in 2020.
  • Surgeries decreased after the first two waves, but patient numbers rebounded in later months, with the third wave not impacting surgical volumes.
  • Despite a reduction in average length of hospital stay and a rise in costs, the study found decreased transfer and readmission rates, suggesting that surgical care adapted well during the pandemic.
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Although one can recognize the environment by soundscape substituting vision to auditory signal, whether subjects could perceive the soundscape as visual or visual-like sensation has been questioned. In this study, we investigated hierarchical process to elucidate the recruitment mechanism of visual areas by soundscape stimuli in blindfolded subjects. Twenty-two healthy subjects were repeatedly trained to recognize soundscape stimuli converted by visual shape information of letters.

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  • Lumbar spinal stenosis (LSS) and spondylolisthesis (SPL) are similar degenerative spinal conditions that have different recommendations regarding exercise, making it challenging to study the impact of physical activity on them.
  • This study examined the effects of restricted physical activity due to social distancing during the pandemic on healthcare visits and costs for patients with LSS and SPL, comparing data from the pandemic period to pre-pandemic.
  • Results showed a significant decrease in hospital visits for both LSS and SPL patients after the implementation of social distancing, with LSS patients also experiencing a notable reduction in medical costs, while SPL patients did not see a significant change in costs.
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Intracranial implants for diagnosis and treatment of brain diseases have been developed over the past few decades. However, the platform of conventional implantable devices still relies on invasive probes and bulky sensors in conjunction with large-area craniotomy and provides only limited biometric information. Here, an implantable multi-modal sensor array that can be injected through a small hole in the skull and inherently spread out for conformal contact with the cortical surface is reported.

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This study aimed to compare the long-term effects of flexion- and extension-based lumbar exercises on chronic axial low back pain (LBP). This was a 1-year follow-up of a prospective, assessor-blind, randomized controlled trial. Patients with axial LBP (intensity ≥ 5/10) for > 6 months allocated to the flexion or extension exercise group.

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Objective: Although adult spinal deformity (ASD) surgery aims to restore and maintain alignment, proximal junctional kyphosis (PJK) may occur. While existing scoring systems predict PJK, they predominantly offer a generalized 3-tier risk classification, limiting their utility for nuanced treatment decisions. This study seeks to establish a personalized risk calculator for PJK, aiming to enhance treatment planning precision.

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Although the role of plain radiographs in diagnosing lumbar spinal stenosis (LSS) has declined in importance since the advent of magnetic resonance imaging (MRI), diagnostic ability of plain radiographs has improved dramatically when combined with deep learning. Previously, we developed a convolutional neural network (CNN) model using a radiograph for diagnosing LSS. In this study, we aimed to improve and generalize the performance of CNN models and overcome the limitation of the single-pose-based CNN (SP-CNN) model using multi-pose radiographs.

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Objective: This study aims to investigate the potential of direct cortical stimulation (DCS) to modulate tactile categorization and decision-making, as well as to identify the specific locations where these cognitive functions occur.

Methods: We analyzed behavioral changes in three epilepsy patients with implanted electrodes using electrocorticography (ECoG) and a vibrotactile discrimination task. DCS was applied to investigate its impact on tactile categorization and decision-making processes.

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From sensory input to motor action, encoded sensory features flow sequentially along cortical networks for decision-making. Despite numerous studies probing the decision-making process, the subprocess that compares encoded sensory features before making a decision has not been fully elucidated in humans. In this study, we investigated sensory feature comparison by presenting two different tasks (a discrimination task, in which participants made decisions by comparing two sequential tactile stimuli; and a detection task, in which participants responded to the second tactile stimulus in two sequential stimuli) to epilepsy patients while recording electrocorticography (ECoG).

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  • The study investigates the effectiveness of the comprehensive Enhanced Recovery After Surgery (ERAS) protocol on spine surgery patients, focusing on both primary spine tumors (PSTs) and degenerative spinal diseases (DSDs).
  • Through a retrospective analysis of 7143 surgical procedures performed at a hospital from 2003 to 2021, the study compares outcomes before and after the full implementation of the ERAS protocol.
  • Results indicate that the ERAS protocol significantly reduced the length of hospital stay and medical costs by 22% overall, with a more notable 28% reduction in the PST group compared to a 16% reduction in the DSD group.
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Although resection is the gold standard treatment for spinal ependymoma, permanent neurological deterioration has been reported postoperatively in 20%-27% of patients. Despite thorough dissection of the tumor from its surroundings, conventional longitudinally directed midline myelotomy can lead to injury to the dorsal column, possibly due to deformation of the posterior median septum as the tumor grows. To address this issue, the authors have been performing precise midline myelotomy through the anatomical posterior median septum by directly dissecting the dorsal column.

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Background And Objectives: Oblique lumbar interbody fusion (OLIF) procedures involve anterior insertion of interbody cage in lateral position. Following OLIF, insertion of pedicle screws and rod system is performed in a prone position (OLIF-con). The location of the cage is important for restoration of lumbar lordosis and indirect decompression.

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