1.L-Point Entry, Juxtapedicular, and Endplate-Parallel Trajectory (L-JET) Screw Fixation: A Novel Technique in Thoracic Spinal Tumor Surgery
Seunghoon LEE ; Young Rak KIM ; Chang-Hyun LEE ; Jungbo SIM ; Woojin KIM ; Ho Sung MYEONG ; Hangeul PARK ; Jun-Hoe KIM ; Chi Heon KIM
Journal of Minimally Invasive Spine Surgery and Technique 2026;11(1):6-13
Objective:
Thoracic pedicle screw fixation is technically demanding because of the natural variability in pedicle anatomy, a challenge that is further exacerbated in patients with spinal tumors who often have compromised pedicles. The L-point entry, juxtapedicular, and endplate-parallel trajectory (L-JET) technique was developed to provide a uniform entry point, a predictable screw trajectory, and the capacity to accommodate larger-diameter screws at levels T3–10. This study aimed to evaluate the safety and feasibility of the L-JET technique in comparison with the conventional transpedicular method.
Methods:
A comparative analysis of consecutively collected data was performed to evaluate outcomes associated with the L-JET technique in patients undergoing surgery for thoracic extradural spinal tumors. The L-point was defined as the intersection of a vertical line along the lateral margin of the facet joint and a horizontal line along the upper edge of the transverse process. The screw trajectory was planned with 30° of medial convergence in the axial plane, creating a juxtapedicular path, and a straightforward trajectory in the sagittal plane. Primary outcome measures included screw diameter, screw length, cortical breach rate, and the need for revision surgery, as assessed using computed tomography scans and medical records.
Results:
A total of 108 screws were placed in 22 patients using the L-JET technique, while 98 screws were placed in 18 patients using the conventional technique. The L-JET group used significantly larger-diameter screws (6.06±0.65 mm) than the conventional group (5.74±0.80 mm, p=0.02), with no significant difference observed in screw length between groups. Medial cortical breach occurred in one screw in each group, and no supra- or infrapedicular breaches were identified. No screw-related neurovascular complications or revision surgeries occurred in either group.
Conclusion
The L-JET technique enables consistent screw placement with larger-diameter screws, even in compromised pedicles associated with thoracic spinal tumors, without increasing the risk of complications or the need for revision surgery.
2.Unilateral Biportal Endoscopic Removal of a Cervical Extradural Schwannoma at the C1–2 Level
Woon Tak YUH ; Il CHOI ; Don Y. PARK ; Chi Heon KIM ; Chun Kee CHUNG
Journal of Minimally Invasive Spine Surgery and Technique 2026;11(Suppl 1):S228-S234
The C1–2 level is a relatively common location for extradural neurogenic tumors. However, surgical access to this region is anatomically demanding because of its close relationship to the vertebral artery and the spinal cord. To our knowledge, there have been no previous reports of using the unilateral biportal endoscopic (UBE) technique for such cases. We present the first successful removal of a C1–2 extradural tumor using UBE, demonstrating the feasibility, safety, and effectiveness of this approach.
3.Impact of obesity on renal function in elderly Korean adults: a national population-based cohort study
Jihyun YANG ; Hui Seung LEE ; Chi-Yeon LIM ; Hyunsuk KIM ; Sungjin CHUNG ; Soon Hyo KWON ; Jang-Hee CHO ; Kyung Don YOO ; Woo Yeong PARK ; In O SUN ; Byung Chul YU ; Gang-Jee KO ; Jae Won YANG ; Won Min HWANG ; Sang Heon SONG ; Sung Joon SHIN ; Yu Ah HONG ; Eunjin BAE ; Young Youl HYUN
Kidney Research and Clinical Practice 2026;45(1):65-76
Background:
Obesity is a well-known risk factor for chronic kidney disease and its progression. However, the impact of obesity on the renal function of the elderly population is uncertain. We investigated the association between obesity and renal outcomes in the elderly.
Methods:
We analyzed 130,504 participants from the Korean National Health Insurance Service-Senior cohort. Obesity was classified according to body mass index (BMI), sex-specific waist circumference (WC), and the presence of metabolic syndrome. The primary outcome was renal function decline, defined as a decline in the estimated glomerular filtration rate (eGFR) of at least 50% from baseline or new-onset end-stage renal disease.
Results:
During a follow-up period of 559,531.1 person-years (median, 4.3 years), 2,486 participants (19.0%; incidence rate of 4.44 per 1,000 person-years) showed renal function decline. A multivariate Cox proportional hazards model revealed that BMI/WC was not associated with renal function decline. However, the group with metabolic syndrome had a significantly increased risk of renal function decline compared to the group without metabolic syndrome (adjusted hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.13–1.36). Compared with the non-metabolic syndrome group, the adjusted HRs (95% CI) for participants with one through five components were 0.96 (0.84–1.11), 1.10 (0.96–1.27), 1.24 (1.06–1.45), 1.37 (1.12–1.66), and 1.99 (1.42–2.79), respectively (p for trend < 0.001).
Conclusion
In elderly Korean adults, metabolic syndrome and the number of its components were associated with a higher risk of renal function decline, but BMI or WC was not significant.
4.Prediction model for 6-month mortality in incident older hemodialysis patients in South Korea
Woo Yeong PARK ; Eunjin BAE ; Hui-Seung LEE ; Chi-Yeon LIM ; Jang-Hee CHO ; Byung Chul YU ; Miyeun HAN ; Sang Heon SONG ; Gang-Jee KO ; Jae Won YANG ; Sungjin CHUNG ; Yu Ah HONG ; Young Youl HYUN ; In O SUN ; Hyunsuk KIM ; Won Min HWANG ; Sung Joon SHIN ; Soon Hyo KWON ; Kyung Don YOO ;
Kidney Research and Clinical Practice 2025;44(4):664-678
Early mortality following hemodialysis initiation hinders survival improvement in older patients. This study aimed to develop a clinical risk model for predicting 6-month mortality after dialysis initiation in older Korean hemodialysis patients. Methods: We analyzed data from incident hemodialysis patients aged >70 years from the Korean Society of Geriatric Nephrology (KSGN) database. A prediction model was developed using multivariate logistic regression analysis and externally validated with independent datasets. Results: Among 1,751 incident hemodialysis patients, the 6-month mortality rate was 15.5%. Using multivariate logistic analysis, we constructed the KSGN score as an independent risk factor for 6-month mortality, and its components and score are as follows: old age at dialysis initiation (≥85 years, score 2); hypertension and renovascular disease as a primary etiology of end-stage kidney disease (ESKD) (score 1); malignancy history (yes, score 1); low serum albumin (<3.5 g/dL, score 1); hypertension treatment (yes, score –1); prepared vascular access on maintenance dialysis (arteriovenous fistula/arteriovenous graft, score –3). In the development cohort, the area under the curve (AUC) for the KSGN score was significantly higher than the Alberta Wick’s score (0.707 vs. 0.683, p = 0.001). In the validation cohort, the KSGN score’s performance was comparable to existing models. Conclusion: The KSGN score may be a valuable tool for predicting early mortality after dialysis initiation in older patients with ESKD, aiding in decision-making and management regarding dialysis initiation.
5.Spinal Schwannoma Classification Based on the Presumed Origin With Preoperative Magnetic Resonance Images
Tae-Shin KIM ; Jae Hee KUH ; Junhoe KIM ; Woon Tak YUH ; Junghoon HAN ; Chang-Hyun LEE ; Chi Heon KIM ; Chun Kee CHUNG
Neurospine 2024;21(3):890-902
Objective:
Classification guides the surgical approach and predicts prognosis. However, existing classifications of spinal schwannomas often result in a high ‘unclassified’ rate. Here, we aim to develop a new comprehensive classification for spinal schwannomas based on their presumed origin. We compared the new classification with the existing classifications regarding the rate of ‘unclassified’. Finally, we assessed the surgical strategies, outcomes, and complications according to each type of the new classification.
Methods:
A new classification with 9 types was created by analyzing the anatomy of spinal nerves and the origin of significant tumor portions and cystic components in preoperative magnetic resonance images. A total of 482 patients with spinal schwannomas were analyzed to compare our new classification with the existing classifications. We defined ‘unclassified’ as the inability to classify a patient with spinal schwannoma using the classification criteria. Surgical approaches and outcomes were also aligned with our new classification.
Results:
Our classification uniquely reported no ‘unclassified’ cases, indicating full applicability. Also, the classification has demonstrated usefulness in predicting the surgical outcome with the approach planned. Gross total removal rates reached 88.0% overall, with type 1 and type 2 tumors at 95.3% and 96.0% respectively. The approach varied with tumor type, with laminectomy predominantly used for types 1, 2, and 9, and facetectomy with posterior fixation used for type 3 tumors.
Conclusion
The new classification for spinal schwannomas based on presumed origin is applicable to all spinal schwannomas. It could help plan a surgical approach and predict its outcome, compared with existing classifications.
6.Spinal Schwannoma Classification Based on the Presumed Origin With Preoperative Magnetic Resonance Images
Tae-Shin KIM ; Jae Hee KUH ; Junhoe KIM ; Woon Tak YUH ; Junghoon HAN ; Chang-Hyun LEE ; Chi Heon KIM ; Chun Kee CHUNG
Neurospine 2024;21(3):890-902
Objective:
Classification guides the surgical approach and predicts prognosis. However, existing classifications of spinal schwannomas often result in a high ‘unclassified’ rate. Here, we aim to develop a new comprehensive classification for spinal schwannomas based on their presumed origin. We compared the new classification with the existing classifications regarding the rate of ‘unclassified’. Finally, we assessed the surgical strategies, outcomes, and complications according to each type of the new classification.
Methods:
A new classification with 9 types was created by analyzing the anatomy of spinal nerves and the origin of significant tumor portions and cystic components in preoperative magnetic resonance images. A total of 482 patients with spinal schwannomas were analyzed to compare our new classification with the existing classifications. We defined ‘unclassified’ as the inability to classify a patient with spinal schwannoma using the classification criteria. Surgical approaches and outcomes were also aligned with our new classification.
Results:
Our classification uniquely reported no ‘unclassified’ cases, indicating full applicability. Also, the classification has demonstrated usefulness in predicting the surgical outcome with the approach planned. Gross total removal rates reached 88.0% overall, with type 1 and type 2 tumors at 95.3% and 96.0% respectively. The approach varied with tumor type, with laminectomy predominantly used for types 1, 2, and 9, and facetectomy with posterior fixation used for type 3 tumors.
Conclusion
The new classification for spinal schwannomas based on presumed origin is applicable to all spinal schwannomas. It could help plan a surgical approach and predict its outcome, compared with existing classifications.
7.Spinal Schwannoma Classification Based on the Presumed Origin With Preoperative Magnetic Resonance Images
Tae-Shin KIM ; Jae Hee KUH ; Junhoe KIM ; Woon Tak YUH ; Junghoon HAN ; Chang-Hyun LEE ; Chi Heon KIM ; Chun Kee CHUNG
Neurospine 2024;21(3):890-902
Objective:
Classification guides the surgical approach and predicts prognosis. However, existing classifications of spinal schwannomas often result in a high ‘unclassified’ rate. Here, we aim to develop a new comprehensive classification for spinal schwannomas based on their presumed origin. We compared the new classification with the existing classifications regarding the rate of ‘unclassified’. Finally, we assessed the surgical strategies, outcomes, and complications according to each type of the new classification.
Methods:
A new classification with 9 types was created by analyzing the anatomy of spinal nerves and the origin of significant tumor portions and cystic components in preoperative magnetic resonance images. A total of 482 patients with spinal schwannomas were analyzed to compare our new classification with the existing classifications. We defined ‘unclassified’ as the inability to classify a patient with spinal schwannoma using the classification criteria. Surgical approaches and outcomes were also aligned with our new classification.
Results:
Our classification uniquely reported no ‘unclassified’ cases, indicating full applicability. Also, the classification has demonstrated usefulness in predicting the surgical outcome with the approach planned. Gross total removal rates reached 88.0% overall, with type 1 and type 2 tumors at 95.3% and 96.0% respectively. The approach varied with tumor type, with laminectomy predominantly used for types 1, 2, and 9, and facetectomy with posterior fixation used for type 3 tumors.
Conclusion
The new classification for spinal schwannomas based on presumed origin is applicable to all spinal schwannomas. It could help plan a surgical approach and predict its outcome, compared with existing classifications.
8.Peripheral ossifying fibroma arising from the maxillary bucco-palatal gingiva in an elderly male patient: a rare case report
Seo-Yeong AN ; Chan Min KIM ; Chi Heon SUNG ; Chul-Hwan KIM
Journal of the Korean Association of Oral and Maxillofacial Surgeons 2024;50(5):292-296
Peripheral ossifying fibroma (POF) is a benign tumor characterized by dystrophic calcification or ossification within the gingiva, primarily affecting the anterior maxilla of females and young adults. Its pathogenesis is unclear but linked to local irritants such as trauma, biofilm, dental calculus, and poorly fitting prostheses. In this study, a 63-year-old male presented at Dankook University Dental Hospital with a large nodular lesion on the left maxillary bucco-palatal gingiva. Preoperative imaging, including panoramic radiography and cone-beam computed tomography, was performed. Surgical excision and histological examination confirmed POF with specific morphological characteristics, including mineralized tissue with varied deposition patterns, mature and immature bone, cementum-like tissue, and dystrophic calcification. In conclusion, POF is a rare oral tumor, more common in younger females, typically presenting asymptomatically on the anterior maxilla. Histopathological analysis is crucial for diagnosis. Standard treatment involves conservative local resection, but recurrence rates range from 8% to 20%, necessitating continuous follow-up. This report aims to enhance understanding of POF by presenting a rare case of a large POF in the maxillary posterior bucco-palatal gingiva of an elderly male.
9.Peripheral ossifying fibroma arising from the maxillary bucco-palatal gingiva in an elderly male patient: a rare case report
Seo-Yeong AN ; Chan Min KIM ; Chi Heon SUNG ; Chul-Hwan KIM
Journal of the Korean Association of Oral and Maxillofacial Surgeons 2024;50(5):292-296
Peripheral ossifying fibroma (POF) is a benign tumor characterized by dystrophic calcification or ossification within the gingiva, primarily affecting the anterior maxilla of females and young adults. Its pathogenesis is unclear but linked to local irritants such as trauma, biofilm, dental calculus, and poorly fitting prostheses. In this study, a 63-year-old male presented at Dankook University Dental Hospital with a large nodular lesion on the left maxillary bucco-palatal gingiva. Preoperative imaging, including panoramic radiography and cone-beam computed tomography, was performed. Surgical excision and histological examination confirmed POF with specific morphological characteristics, including mineralized tissue with varied deposition patterns, mature and immature bone, cementum-like tissue, and dystrophic calcification. In conclusion, POF is a rare oral tumor, more common in younger females, typically presenting asymptomatically on the anterior maxilla. Histopathological analysis is crucial for diagnosis. Standard treatment involves conservative local resection, but recurrence rates range from 8% to 20%, necessitating continuous follow-up. This report aims to enhance understanding of POF by presenting a rare case of a large POF in the maxillary posterior bucco-palatal gingiva of an elderly male.
10.Spinal Schwannoma Classification Based on the Presumed Origin With Preoperative Magnetic Resonance Images
Tae-Shin KIM ; Jae Hee KUH ; Junhoe KIM ; Woon Tak YUH ; Junghoon HAN ; Chang-Hyun LEE ; Chi Heon KIM ; Chun Kee CHUNG
Neurospine 2024;21(3):890-902
Objective:
Classification guides the surgical approach and predicts prognosis. However, existing classifications of spinal schwannomas often result in a high ‘unclassified’ rate. Here, we aim to develop a new comprehensive classification for spinal schwannomas based on their presumed origin. We compared the new classification with the existing classifications regarding the rate of ‘unclassified’. Finally, we assessed the surgical strategies, outcomes, and complications according to each type of the new classification.
Methods:
A new classification with 9 types was created by analyzing the anatomy of spinal nerves and the origin of significant tumor portions and cystic components in preoperative magnetic resonance images. A total of 482 patients with spinal schwannomas were analyzed to compare our new classification with the existing classifications. We defined ‘unclassified’ as the inability to classify a patient with spinal schwannoma using the classification criteria. Surgical approaches and outcomes were also aligned with our new classification.
Results:
Our classification uniquely reported no ‘unclassified’ cases, indicating full applicability. Also, the classification has demonstrated usefulness in predicting the surgical outcome with the approach planned. Gross total removal rates reached 88.0% overall, with type 1 and type 2 tumors at 95.3% and 96.0% respectively. The approach varied with tumor type, with laminectomy predominantly used for types 1, 2, and 9, and facetectomy with posterior fixation used for type 3 tumors.
Conclusion
The new classification for spinal schwannomas based on presumed origin is applicable to all spinal schwannomas. It could help plan a surgical approach and predict its outcome, compared with existing classifications.

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