1.Nerve Root Herniation Due to Delayed Dural Tear Following Unilateral Laminotomy for Bilateral Decompression With Lumbar Discectomy Using Unilateral Biportal Endoscopy
Sang Hyub LEE ; Jae-Won JANG ; Yong Eun CHO ; Choon Keun PARK
Journal of Minimally Invasive Spine Surgery and Technique 2026;11(Suppl 1):S109-S115
This case report describes a delayed dural tear with subsequent nerve root herniation following unilateral laminotomy for bilateral decompression (ULBD) combined with lumbar discectomy using unilateral biportal endoscopy (UBE). A 31-year-old woman underwent UBE ULBD with lumbar discectomy via a left-sided approach for extremely severe L4–5 central canal stenosis with a central disc herniation. No dural tear occurred intraoperatively; however, the dorsal dura was extremely thinned and translucent, with the nerve roots faintly visible through the thecal sac. Following the initial operation, the patient’s symptoms improved, and she was discharged without complications. One week later, the patient developed recurrent severe radiating pain in the left leg. Follow-up magnetic resonance imaging (MRI) revealed cerebrospinal fluid (CSF) leakage and findings suspicious for nerve root herniation. Revision surgery was performed to reduce the herniated nerve root and repair the dural tear. After revision surgery, the patient’s symptoms improved, and postoperative MRI obtained 1 week later showed no evidence of CSF leakage. During 6 months of follow-up, no further complications were observed. Delayed dural tear with nerve root herniation is rare but clinically significant, and revision surgery is often unavoidable. Prophylactic reinforcement may be advisable when translucent, thinned dura is encountered.
2.Unilateral Biportal Endoscopic Transforaminal Lumbar Interbody Fusion (TLIF) Using 3-Dimensional-Printed Titanium Cages Compared With Open TLIF: A Comparison of Clinical Outcomes and Fusion Rates
Sang Hyub LEE ; Junghan SEO ; Dain JEONG ; Sang Youp HAN ; Dong Hyun LEE ; Jae-Won JANG ; Dong-Geun LEE ; Choon Keun PARK
Journal of Minimally Invasive Spine Surgery and Technique 2026;11(Suppl 1):S28-S40
Objective:
Unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) has emerged as an alternative to open TLIF. However, limited evidence is available regarding the application of 3-dimensional (3D)-printed titanium cages in UBE-TLIF. We aimed to compare the clinical outcomes and fusion rates of UBE-TLIF and open TLIF using 3D-printed titanium cages.
Methods:
We retrospectively reviewed patients who underwent single-level TLIF with 3D-printed titanium cages between 2021 and 2023. The inclusion criterion was degenerative lumbar stenosis, while the exclusion criteria were trauma, infection, and multilevel surgery. Clinical and radiologic outcomes were compared between the UBE-TLIF and open TLIF groups.
Results:
Twenty-one patients underwent UBE-TLIF, and 21 underwent open TLIF. The visual analogue scale (VAS) for back (p=0.987) and leg pain (p=0.731) did not significantly differ between the groups at 1-year follow-up. However, VAS back pain at postoperative day 2 was significantly lower in the UBE-TLIF group than in the open TLIF group (p<0.001). Solid fusion was achieved in 21 patients (100%) in the open TLIF group and in 20 (95.2%) in the UBE-TLIF group (p=1.000). In multivariable logistic regression analysis, body mass index was the only factor that exhibited a significant relationship (odds ratio [OR], 0.70; 95% confidence interval [CI], 0.53–0.92; p=0.011) with interbody fusion. In contrast, the surgical method (UBE vs. open TLIF) was not a significant factor (OR, 0.47; 95% CI, 0.10–2.21; p=0.337).
Conclusion
Using a 3D-printed titanium cage for UBE-TLIF may yield comparable fusion rates to those of open TLIF.
3.Far-Lateral Transforaminal Unilateral Biportal Endoscopic Lumbar Discectomy for Upper Lumbar Disc Herniations
Jin Seop HWANG ; Sang Hyub LEE ; Dain JEONG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK ; Chung Kee CHOUGH
Neurospine 2025;22(1):14-27
Objective:
The upper lumbar region has distinctive anatomical characteristics that contribute to the challenges of performing discectomy. We introduce far-lateral transforaminal unilateral biportal endoscopic (UBE) lumbar discectomy for central or paracentral disc herniations in the upper lumbar region.
Methods:
We conducted retrospective review of the patients who underwent a far-lateral transforaminal UBE lumbar discectomy at our institution from January 2018 to September 2024. The electronic medical records, operative records, and radiologic images of the patients were reviewed.
Results:
A total of 27 patients underwent far-lateral transforaminal UBE lumbar discectomy for central or paracentral disc herniations in the upper lumbar region. The patient had a mean age of 54.0 ± 13.7 years. Operation was performed at the L1–2 level in 3 patients (11.1%), L2–3 in 9 patients (33.3%), and L3–4 in 15 patients (55.6%). The patients were followed-up for a mean of 27.7 ± 19.3 months. The Oswestry Disability Index was significantly decreased from 36.3 ± 6.8 preoperatively to 3.7 ± 3.3 at last follow-up (p < 0.001). The visual analogue scale (VAS) back was significantly decreased from 7.8 ± 0.9 preoperatively to 3.1 ± 0.6 postoperative day 2 (p < 0.001). The VAS leg was significantly decreased from 8.1 ± 0.8 preoperatively to 2.3 ± 0.7 postoperative day 2 (p < 0.001).
Conclusion
The far-lateral transforaminal UBE lumbar discectomy would be a viable surgical option for upper lumbar disc herniations.
4.O-arm navigation-based transforaminal unilateral biportal endoscopic discectomy for upper lumbar disc herniation: an innovative preliminary study
Dong Hyun LEE ; Choon Keun PARK ; Jin-Sung KIM ; Jin Sub HWANG ; Jin Young LEE ; Dong-Geun LEE ; Jae-Won JANG ; Jun Yong KIM ; Yong-Eun CHO ; Dong Chan LEE
Asian Spine Journal 2025;19(2):194-204
Methods:
The UBE approach targeted the ventral part of the superior articular process in the transforaminal UBE setup, specifically for upper lumbar disc herniation, with an approach angle of approximately 30º on the axial plane. Intraoperative navigation was employed to improve puncture accuracy for this relatively unfamiliar surgical technique. Navigation-assisted transforaminal UBE lumbar discectomy was performed on four patients presenting with back or leg discomfort due to disc herniation at the L1–L2 or L2–L3 levels.
Results:
All patients experienced symptom relief and were discharged on postoperative day 2.
Conclusions
Transforaminal UBE lumbar discectomy is a viable therapeutic option for upper lumbar paracentral disc herniation, which is typically associated with poor prognosis. Integrating navigation integration into this novel approach enhances precision and safety.
5.Far-Lateral Transforaminal Unilateral Biportal Endoscopic Lumbar Discectomy for Upper Lumbar Disc Herniations
Jin Seop HWANG ; Sang Hyub LEE ; Dain JEONG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK ; Chung Kee CHOUGH
Neurospine 2025;22(1):14-27
Objective:
The upper lumbar region has distinctive anatomical characteristics that contribute to the challenges of performing discectomy. We introduce far-lateral transforaminal unilateral biportal endoscopic (UBE) lumbar discectomy for central or paracentral disc herniations in the upper lumbar region.
Methods:
We conducted retrospective review of the patients who underwent a far-lateral transforaminal UBE lumbar discectomy at our institution from January 2018 to September 2024. The electronic medical records, operative records, and radiologic images of the patients were reviewed.
Results:
A total of 27 patients underwent far-lateral transforaminal UBE lumbar discectomy for central or paracentral disc herniations in the upper lumbar region. The patient had a mean age of 54.0 ± 13.7 years. Operation was performed at the L1–2 level in 3 patients (11.1%), L2–3 in 9 patients (33.3%), and L3–4 in 15 patients (55.6%). The patients were followed-up for a mean of 27.7 ± 19.3 months. The Oswestry Disability Index was significantly decreased from 36.3 ± 6.8 preoperatively to 3.7 ± 3.3 at last follow-up (p < 0.001). The visual analogue scale (VAS) back was significantly decreased from 7.8 ± 0.9 preoperatively to 3.1 ± 0.6 postoperative day 2 (p < 0.001). The VAS leg was significantly decreased from 8.1 ± 0.8 preoperatively to 2.3 ± 0.7 postoperative day 2 (p < 0.001).
Conclusion
The far-lateral transforaminal UBE lumbar discectomy would be a viable surgical option for upper lumbar disc herniations.
6.Far-Lateral Transforaminal Unilateral Biportal Endoscopic Lumbar Discectomy for Upper Lumbar Disc Herniations
Jin Seop HWANG ; Sang Hyub LEE ; Dain JEONG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK ; Chung Kee CHOUGH
Neurospine 2025;22(1):14-27
Objective:
The upper lumbar region has distinctive anatomical characteristics that contribute to the challenges of performing discectomy. We introduce far-lateral transforaminal unilateral biportal endoscopic (UBE) lumbar discectomy for central or paracentral disc herniations in the upper lumbar region.
Methods:
We conducted retrospective review of the patients who underwent a far-lateral transforaminal UBE lumbar discectomy at our institution from January 2018 to September 2024. The electronic medical records, operative records, and radiologic images of the patients were reviewed.
Results:
A total of 27 patients underwent far-lateral transforaminal UBE lumbar discectomy for central or paracentral disc herniations in the upper lumbar region. The patient had a mean age of 54.0 ± 13.7 years. Operation was performed at the L1–2 level in 3 patients (11.1%), L2–3 in 9 patients (33.3%), and L3–4 in 15 patients (55.6%). The patients were followed-up for a mean of 27.7 ± 19.3 months. The Oswestry Disability Index was significantly decreased from 36.3 ± 6.8 preoperatively to 3.7 ± 3.3 at last follow-up (p < 0.001). The visual analogue scale (VAS) back was significantly decreased from 7.8 ± 0.9 preoperatively to 3.1 ± 0.6 postoperative day 2 (p < 0.001). The VAS leg was significantly decreased from 8.1 ± 0.8 preoperatively to 2.3 ± 0.7 postoperative day 2 (p < 0.001).
Conclusion
The far-lateral transforaminal UBE lumbar discectomy would be a viable surgical option for upper lumbar disc herniations.
7.Far-Lateral Transforaminal Unilateral Biportal Endoscopic Lumbar Discectomy for Upper Lumbar Disc Herniations
Jin Seop HWANG ; Sang Hyub LEE ; Dain JEONG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK ; Chung Kee CHOUGH
Neurospine 2025;22(1):14-27
Objective:
The upper lumbar region has distinctive anatomical characteristics that contribute to the challenges of performing discectomy. We introduce far-lateral transforaminal unilateral biportal endoscopic (UBE) lumbar discectomy for central or paracentral disc herniations in the upper lumbar region.
Methods:
We conducted retrospective review of the patients who underwent a far-lateral transforaminal UBE lumbar discectomy at our institution from January 2018 to September 2024. The electronic medical records, operative records, and radiologic images of the patients were reviewed.
Results:
A total of 27 patients underwent far-lateral transforaminal UBE lumbar discectomy for central or paracentral disc herniations in the upper lumbar region. The patient had a mean age of 54.0 ± 13.7 years. Operation was performed at the L1–2 level in 3 patients (11.1%), L2–3 in 9 patients (33.3%), and L3–4 in 15 patients (55.6%). The patients were followed-up for a mean of 27.7 ± 19.3 months. The Oswestry Disability Index was significantly decreased from 36.3 ± 6.8 preoperatively to 3.7 ± 3.3 at last follow-up (p < 0.001). The visual analogue scale (VAS) back was significantly decreased from 7.8 ± 0.9 preoperatively to 3.1 ± 0.6 postoperative day 2 (p < 0.001). The VAS leg was significantly decreased from 8.1 ± 0.8 preoperatively to 2.3 ± 0.7 postoperative day 2 (p < 0.001).
Conclusion
The far-lateral transforaminal UBE lumbar discectomy would be a viable surgical option for upper lumbar disc herniations.
8.O-arm navigation-based transforaminal unilateral biportal endoscopic discectomy for upper lumbar disc herniation: an innovative preliminary study
Dong Hyun LEE ; Choon Keun PARK ; Jin-Sung KIM ; Jin Sub HWANG ; Jin Young LEE ; Dong-Geun LEE ; Jae-Won JANG ; Jun Yong KIM ; Yong-Eun CHO ; Dong Chan LEE
Asian Spine Journal 2025;19(2):194-204
Methods:
The UBE approach targeted the ventral part of the superior articular process in the transforaminal UBE setup, specifically for upper lumbar disc herniation, with an approach angle of approximately 30º on the axial plane. Intraoperative navigation was employed to improve puncture accuracy for this relatively unfamiliar surgical technique. Navigation-assisted transforaminal UBE lumbar discectomy was performed on four patients presenting with back or leg discomfort due to disc herniation at the L1–L2 or L2–L3 levels.
Results:
All patients experienced symptom relief and were discharged on postoperative day 2.
Conclusions
Transforaminal UBE lumbar discectomy is a viable therapeutic option for upper lumbar paracentral disc herniation, which is typically associated with poor prognosis. Integrating navigation integration into this novel approach enhances precision and safety.
9.Far-Lateral Transforaminal Unilateral Biportal Endoscopic Lumbar Discectomy for Upper Lumbar Disc Herniations
Jin Seop HWANG ; Sang Hyub LEE ; Dain JEONG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK ; Chung Kee CHOUGH
Neurospine 2025;22(1):14-27
Objective:
The upper lumbar region has distinctive anatomical characteristics that contribute to the challenges of performing discectomy. We introduce far-lateral transforaminal unilateral biportal endoscopic (UBE) lumbar discectomy for central or paracentral disc herniations in the upper lumbar region.
Methods:
We conducted retrospective review of the patients who underwent a far-lateral transforaminal UBE lumbar discectomy at our institution from January 2018 to September 2024. The electronic medical records, operative records, and radiologic images of the patients were reviewed.
Results:
A total of 27 patients underwent far-lateral transforaminal UBE lumbar discectomy for central or paracentral disc herniations in the upper lumbar region. The patient had a mean age of 54.0 ± 13.7 years. Operation was performed at the L1–2 level in 3 patients (11.1%), L2–3 in 9 patients (33.3%), and L3–4 in 15 patients (55.6%). The patients were followed-up for a mean of 27.7 ± 19.3 months. The Oswestry Disability Index was significantly decreased from 36.3 ± 6.8 preoperatively to 3.7 ± 3.3 at last follow-up (p < 0.001). The visual analogue scale (VAS) back was significantly decreased from 7.8 ± 0.9 preoperatively to 3.1 ± 0.6 postoperative day 2 (p < 0.001). The VAS leg was significantly decreased from 8.1 ± 0.8 preoperatively to 2.3 ± 0.7 postoperative day 2 (p < 0.001).
Conclusion
The far-lateral transforaminal UBE lumbar discectomy would be a viable surgical option for upper lumbar disc herniations.
10.O-arm navigation-based transforaminal unilateral biportal endoscopic discectomy for upper lumbar disc herniation: an innovative preliminary study
Dong Hyun LEE ; Choon Keun PARK ; Jin-Sung KIM ; Jin Sub HWANG ; Jin Young LEE ; Dong-Geun LEE ; Jae-Won JANG ; Jun Yong KIM ; Yong-Eun CHO ; Dong Chan LEE
Asian Spine Journal 2025;19(2):194-204
Methods:
The UBE approach targeted the ventral part of the superior articular process in the transforaminal UBE setup, specifically for upper lumbar disc herniation, with an approach angle of approximately 30º on the axial plane. Intraoperative navigation was employed to improve puncture accuracy for this relatively unfamiliar surgical technique. Navigation-assisted transforaminal UBE lumbar discectomy was performed on four patients presenting with back or leg discomfort due to disc herniation at the L1–L2 or L2–L3 levels.
Results:
All patients experienced symptom relief and were discharged on postoperative day 2.
Conclusions
Transforaminal UBE lumbar discectomy is a viable therapeutic option for upper lumbar paracentral disc herniation, which is typically associated with poor prognosis. Integrating navigation integration into this novel approach enhances precision and safety.

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