1.A Facet-Preserving Modified Transpedicular Approach Using Unilateral Biportal Endoscopy for Thoracic Spinal Pathology
Yong Jin PARK ; Sang Kyu SON ; Young San KO
Journal of Minimally Invasive Spine Surgery and Technique 2026;11(Suppl 1):S214-S218
This study aimed to describe a facet-preserving modified transpedicular unilateral biportal endoscopic (UBE) approach for upwardly migrated thoracic disc herniation that allows safe decompression without spinal cord retraction or postoperative instability. Thoracic disc herniation is rare but often symptomatic, producing myelopathy that typically necessitates surgical intervention. Because of the spinal cord’s close proximity, traditional discectomy approaches carry a high risk of neural injury, and achieving complete disc removal without cord manipulation remains a significant surgical challenge. Although several techniques have been proposed, many are limited by the potential for incomplete decompression or iatrogenic instability. A facet-preserving modified transpedicular UBE approach may overcome these limitations by offering a minimally invasive surgical corridor while maintaining spinal stability. A 76-year-old woman presented with progressive bilateral lower extremity weakness and numbness over 6 months, with rapid deterioration during the past month. Magnetic resonance imaging (MRI) revealed an upwardly migrated thoracic disc herniation at T10–11 compressing the spinal cord. A UBE discectomy using a facet-preserving modified transpedicular approach was performed. The herniated fragment was completely removed without spinal cord retraction. Postoperatively, the patient demonstrated neurological improvement without complications. MRI confirmed complete decompression of the cord, and computed tomography verified preservation of the facet joint. This video article introduces the modified transpedicular UBE approach as a safe and precise minimally invasive technique for thoracic ventral pathologies. By enabling direct ventral decompression while preserving spinal stability, it broadens the scope of endoscopic spine surgery and warrants further clinical validation.
2.Learning Curve Analysis: Impact of Ligamentum Flavum Removal Methods on Unilateral Biportal Endoscopic Laminectomy for Lumbar Spinal Stenosis
Woo Hyeong JOE ; Sae min KWON ; Chang-Young LEE ; Chang-Hyun KIM ; Min-Yong KWON ; Jae Hyun KIM ; In soo KIM ; Young San KO
Journal of Minimally Invasive Spine Surgery and Technique 2025;10(1):131-140
Objective:
Despite the increasingly widespread adoption of unilateral biportal endoscopic (UBE) decompressive laminectomy for lumbar spinal stenosis, the learning curve for surgeons new to endoscopic techniques remains a significant barrier. This study aimed to quantify this learning curve and identify strategies to expedite proficiency, focusing on reducing operative times and complications.
Methods:
The cumulative summation test was used to evaluate the learning curves for both the operative time and the degree of intraoperative dural tear occurrence. Moreover, clinical outcomes and postoperative complications were compared between the cranial and caudal approaches, depending on the direction of ligamentum flavum removal.
Results:
In total, 54 patients were included, with 22 in the cranial group and 32 in the caudal group. The operative time was notably shorter in the caudal group (cranial group, 110.86±32.63 minutes; caudal group, 79.56±24.21 minutes; p<0.01), and the complication rate was considerably lower (cranial group, 40%; caudal group, 15%; p=0.04). Twenty-six patients and 29 patients were needed to overcome the learning curves for operative time and intraoperative dural tear occurrence, respectively.
Conclusion
Although UBE surgery has a short learning curve, a considerable number of cases (26 and 29, respectively) were needed to achieve competency in terms of operative time and intraoperative dural tear occurrence. We highlight the caudal-to-cranial direction of ligamentum flavum dissection and removal as a way to decrease the number of dural tears and shorten the operative time.
3.The efficacy of therapeutic hypothermia in patients with poor-grade aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis
Seungjoo LEE ; Moinay KIM ; Min-Yong KWON ; Sae Min KWON ; Young San KO ; Yeongu CHUNG ; Wonhyoung PARK ; Jung Cheol PARK ; Jae Sung AHN ; Hanwool JEON ; Jihyun IM ; Jae Hyun KIM
Acute and Critical Care 2024;39(2):282-293
This study evaluates the effectiveness of Therapeutic Hypothermia (TH) in treating poor-grade aneurysmal subarachnoid hemorrhage (SAH), focusing on functional outcomes, mortality, and complications such as vasospasm, delayed cerebral ischemia (DCI), and hydrocephalus. Methods: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, a comprehensive literature search was conducted across multiple databases, including Medline, Embase, and Cochrane Central, up to November 2023. Nine studies involving 368 patients were selected based on eligibility criteria focusing on TH in poor-grade SAH patients. Data extraction, bias assessment, and evidence certainty were systematically performed. Results: The primary analysis of unfavorable outcomes in 271 participants showed no significant difference between the TH and standard care groups (risk ratio [RR], 0.87). However, a significant reduction in vasospasm was observed in the TH group (RR, 0.63) among 174 participants. No significant differences were found in DCI, hydrocephalus, and mortality rates in the respective participant groups. Conclusions: TH did not significantly improve primary unfavorable outcomes in poor-grade SAH patients. However, the reduction in vasospasm rates indicates potential specific benefits. The absence of significant findings in other secondary outcomes and mortality highlights the need for further research to better understand TH's role in treating this patient population.
4.The efficacy of therapeutic hypothermia in patients with poor-grade aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis
Seungjoo LEE ; Moinay KIM ; Min-Yong KWON ; Sae Min KWON ; Young San KO ; Yeongu CHUNG ; Wonhyoung PARK ; Jung Cheol PARK ; Jae Sung AHN ; Hanwool JEON ; Jihyun IM ; Jae Hyun KIM
Acute and Critical Care 2024;39(2):282-293
This study evaluates the effectiveness of Therapeutic Hypothermia (TH) in treating poor-grade aneurysmal subarachnoid hemorrhage (SAH), focusing on functional outcomes, mortality, and complications such as vasospasm, delayed cerebral ischemia (DCI), and hydrocephalus. Methods: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, a comprehensive literature search was conducted across multiple databases, including Medline, Embase, and Cochrane Central, up to November 2023. Nine studies involving 368 patients were selected based on eligibility criteria focusing on TH in poor-grade SAH patients. Data extraction, bias assessment, and evidence certainty were systematically performed. Results: The primary analysis of unfavorable outcomes in 271 participants showed no significant difference between the TH and standard care groups (risk ratio [RR], 0.87). However, a significant reduction in vasospasm was observed in the TH group (RR, 0.63) among 174 participants. No significant differences were found in DCI, hydrocephalus, and mortality rates in the respective participant groups. Conclusions: TH did not significantly improve primary unfavorable outcomes in poor-grade SAH patients. However, the reduction in vasospasm rates indicates potential specific benefits. The absence of significant findings in other secondary outcomes and mortality highlights the need for further research to better understand TH's role in treating this patient population.
5.The efficacy of therapeutic hypothermia in patients with poor-grade aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis
Seungjoo LEE ; Moinay KIM ; Min-Yong KWON ; Sae Min KWON ; Young San KO ; Yeongu CHUNG ; Wonhyoung PARK ; Jung Cheol PARK ; Jae Sung AHN ; Hanwool JEON ; Jihyun IM ; Jae Hyun KIM
Acute and Critical Care 2024;39(2):282-293
This study evaluates the effectiveness of Therapeutic Hypothermia (TH) in treating poor-grade aneurysmal subarachnoid hemorrhage (SAH), focusing on functional outcomes, mortality, and complications such as vasospasm, delayed cerebral ischemia (DCI), and hydrocephalus. Methods: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, a comprehensive literature search was conducted across multiple databases, including Medline, Embase, and Cochrane Central, up to November 2023. Nine studies involving 368 patients were selected based on eligibility criteria focusing on TH in poor-grade SAH patients. Data extraction, bias assessment, and evidence certainty were systematically performed. Results: The primary analysis of unfavorable outcomes in 271 participants showed no significant difference between the TH and standard care groups (risk ratio [RR], 0.87). However, a significant reduction in vasospasm was observed in the TH group (RR, 0.63) among 174 participants. No significant differences were found in DCI, hydrocephalus, and mortality rates in the respective participant groups. Conclusions: TH did not significantly improve primary unfavorable outcomes in poor-grade SAH patients. However, the reduction in vasospasm rates indicates potential specific benefits. The absence of significant findings in other secondary outcomes and mortality highlights the need for further research to better understand TH's role in treating this patient population.
6.The efficacy of therapeutic hypothermia in patients with poor-grade aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis
Seungjoo LEE ; Moinay KIM ; Min-Yong KWON ; Sae Min KWON ; Young San KO ; Yeongu CHUNG ; Wonhyoung PARK ; Jung Cheol PARK ; Jae Sung AHN ; Hanwool JEON ; Jihyun IM ; Jae Hyun KIM
Acute and Critical Care 2024;39(2):282-293
This study evaluates the effectiveness of Therapeutic Hypothermia (TH) in treating poor-grade aneurysmal subarachnoid hemorrhage (SAH), focusing on functional outcomes, mortality, and complications such as vasospasm, delayed cerebral ischemia (DCI), and hydrocephalus. Methods: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, a comprehensive literature search was conducted across multiple databases, including Medline, Embase, and Cochrane Central, up to November 2023. Nine studies involving 368 patients were selected based on eligibility criteria focusing on TH in poor-grade SAH patients. Data extraction, bias assessment, and evidence certainty were systematically performed. Results: The primary analysis of unfavorable outcomes in 271 participants showed no significant difference between the TH and standard care groups (risk ratio [RR], 0.87). However, a significant reduction in vasospasm was observed in the TH group (RR, 0.63) among 174 participants. No significant differences were found in DCI, hydrocephalus, and mortality rates in the respective participant groups. Conclusions: TH did not significantly improve primary unfavorable outcomes in poor-grade SAH patients. However, the reduction in vasospasm rates indicates potential specific benefits. The absence of significant findings in other secondary outcomes and mortality highlights the need for further research to better understand TH's role in treating this patient population.
7.Natural course of chronic subdural hematoma following surgical clipping of unruptured intracranial aneurysm by pterional approach
Su-Bin KWEON ; Suchel KIM ; Min-Yong KWON ; Chang-Hyun KIM ; Sae Min KWON ; Yong San KO ; Chang-Young LEE
Journal of Cerebrovascular and Endovascular Neurosurgery 2023;25(4):390-402
Objective:
Chronic subdural hematoma (CSDH) is a neurological complication following clipping surgery. However, the natural course and ideal approach for the treatment of clipping-related-CSDH (CR-CSDH) have not been clearly established. We aimed to investigate the course of CR-CSDH using chronological radiological findings.
Methods:
We performed a retrospective analysis of 28 (3.8%) patients who developed CSDH among 736 patients who underwent surgical clipping using pterional approach for unruptured aneurysms at our institution between December 2010 and December 2018. Patients underwent follow-up CT scan 6–8 weeks after clipping surgery and decision to pursue surgical intervention rests upon the patient’s symptom based on the Markwalder’s grading scale (MGS) and numeric rating scale (NRS).
Results:
Of the 28 patients, 3 patients (10.7%) underwent surgery, while 25 (89.2%) showed spontaneous resolution of CR-CSDH. Eighteen patients (64.2%) had mild headache with MGS of 0–1. The mean maximum hematoma volume was 41.9±30.9 ml (5.8–135 ml), and 26 patients (92.8%) had homogeneous hematoma. The mean time to hematoma resolution was 126.7±52.9 days (46–228 days). Comparing group of CR-CSDH volume ≥43 ml or a midline shift ≥5 mm, the difference in presence of linear low-density area (p=0.002) and age (p=0.026) between the conservative and operative groups were found to be statistically significant.
Conclusions
Most CR-CSDH cases spontaneously resolved within 4 months. Therefore, we suggest that close observation should be performed if patient’s symptoms are mild and special radiologic findings are present, despite its relatively large volume and midline shifting.
8.Efficacy of 3D-printed simulation models of unruptured intracranial aneurysms in patient education and surgical simulation
Seung-Bin WOO ; Chang-Young LEE ; Chang-Hyun KIM ; Min-Yong KWON ; Young San KO ; Jong-Ha LEE ; Jin-Chul HEO ; Sae Min KWON
Journal of Cerebrovascular and Endovascular Neurosurgery 2023;25(1):19-27
Objective:
The purpose of this study was to determine the efficacy of a 3D-printed aneurysm simulation model (3DPM) in educating patients and improving physicians’ comprehension and performance.
Methods:
This prospective study involved 40 patients who were diagnosed with unruptured intracranial aneurysms (UIAs) and scheduled for surgical clipping or endovascular coiling and randomly divided into two groups (the 3DPM group and the non-3DPM group). The 3DPM was used in preoperative consultation with patients and intraoperatively referenced by surgeons. The patients, 7 neurosurgical residents, and 10 surgeons completed questionnaires (5-point Likert scale) to determine the usefulness of the 3DPM.
Results:
Patients in the 3DPM group had significantly higher scores in terms of their understanding of the disease (mean 4.85 vs. 3.95, p<0.001) and the treatment plan (mean 4.85 vs. 4.20, p=0.005) and reported higher satisfaction during consultation (5.0 vs. 4.60, p=0.036) than patients in the non-3DPM group. During patient consultation, 3DPMs were most useful in improving doctor–patient communication (mean 4.57, range 4-5). During clipping surgery, the models were most useful in assessing adjacent arteries (mean 4.9, range 4-5); during endovascular coiling, they were especially helpful in microcatheter shaping (mean 4.7, range 4-5).
Conclusions
In general, 3DPMs are beneficial in educating patients and improving the physician’s performance in terms of surgical clipping and endovascular coiling of UIAs.
9.Does the Surgical Approach Matter in Treating Odontoid Fractures?A Comparison of Mechanical Complication Rates Between Anterior Versus Posterior Surgical Approaches: A Meta-Analysis and Systematic Review
Woong Rae JO ; Chang-Young LEE ; Sae Min KWON ; Chang-Hyun K KIM ; Min-Yong KWON ; Jae Hyun KIM ; Young San KO
Korean Journal of Neurotrauma 2023;19(4):409-421
Objective:
Odontoid fractures are treated surgically through the anterior or posterior approach. Each surgical approach has its advantages and disadvantages, so the preferred approach remains debatable. There are few meta-analyses or systemic reviews on the mechanical complications of surgical treatment for odontoid fractures. This meta-analysis aimed to compare the operation-related morbidity, including mechanical complications, and mortality of patients with odontoid fractures, treated via the anterior or posterior approach.
Methods:
A systematic search was performed on PubMed/Medline, Embase, and the Cochrane Library for the studies up to October 2023 on the complication rate of the surgical treatment of odontoid fractures, related to the surgical approach. The risk ratios (RR) with the 95% confidence intervals (CIs) were pooled to assess the mechanical complication rates, other complications, revision surgery, and mortality, depending on the surgical approach.
Results:
A total of 1,519 studies were retrieved using the search strategy, and 782 patients from 15 articles were included in this meta-analysis. Mechanical complications were significantly more frequent in the anterior surgical group with low heterogeneity. The incidences of fracture nonunion and revision surgery were also higher in the anterior surgery group. However, there was no significant difference in systemic complications and mortality rates between the two groups.
Conclusion
The posterior approach was more advantageous than the anterior approach in terms of mechanical complications, fusion rates, and incidence of revision surgery. However, further studies, should be performed to strengthen these results.
10.Evaluation of Stent Apposition in the LVIS Blue Stent-Assisted Coiling of Distal Internal Carotid Artery Aneurysms : Correlation with Clinical and Angiographic Outcomes
Min-Yong KWON ; Young San KO ; Sae Min KWON ; Chang-Hyun KIM ; Chang-Young LEE
Journal of Korean Neurosurgical Society 2022;65(6):801-815
Objective:
: To evaluate the stent apposition of a low-profile visualized intraluminal support (LVIS) device in distal internal carotid artery (ICA) aneurysms, examine its correlation with clinical and angiographic outcomes, and determine the predictive factors of ischemic adverse events (IAEs) related to stent-assisted coiling.
Methods:
: We retrospectively analyzed a prospectively maintained database of 183 patients between January 2017 and February 2020. The carotid siphon from the cavernous ICA to the ICA terminus was divided into posterior, anterior, and superior bends. The anterior bends were categorized into angled (V) and non-angled (C, U, and S) types depending on the morphology and measured angles. Complete stent apposition (CSA) and incomplete stent apposition (ISA) were evaluated using unsubtracted angiography and flat-panel detector computed tomography. Dual antiplatelet therapy with aspirin 200 mg and clopidogrel 75 mg was administered. Clopidogrel resistance was defined as fewer responders (≥10%, <40%) and non-responders (<10%) based on the percent inhibition (%INH) of the VerifyNow system. These were counteracted by a dose escalation to 150 mg for fewer responders or substitution with cilostazol 200 mg for non-responders. IAEs included intraoperative in-stent thrombosis, transient ischemic attack, cerebral infarction, and delayed in-stent stenosis. A multivariate logistic regression analysis was used to determine the predictive factors for ISA and IAEs.
Results:
: There were 33 ISAs (18.0%) and 27 IAEs (14.8%). The anterior bend angle was narrower in ISA (-4.16°±25.18°) than in CSA (23.52°±23.13°) (p<0.001). The V- and S-types were independently correlated with the ISA (p<0.001). However, treatment outcomes, including IAEs (15.3% vs. 12.1%), aneurysmal complete occlusion (91.3% vs. 88.6%), and recanalization (none of them), did not differ between CSA and ISA (p>0.05). The %INH of 27 IAEs (13.78%±14.78%) was significantly lower than that of 156 non-IAEs (26.82%±20.23%) (p<0.001). Non-responders to clopidogrel were the only significant predictive factor for IAEs (p=0.001).
Conclusion
: The angled and tortuous anatomical peculiarity of the carotid siphon caused ISA of the LVIS device; however, it did not affect clinical and angiographic outcomes, while the non-responders to clopidogrel affected the IAEs related to stent-assisted coiling.

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