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.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.
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.Unilateral Biportal Endoscopic Discectomy for Upper Thoracic Herniated Discs (T1–2): A Case Report and Technical Notes
Bang-Sang HAHN ; Choon Keun PARK ; Jin Sub HWANG ; Yong-Eun CHO ; Jae-Won JANG ; Dong-Geun LEE
Journal of Minimally Invasive Spine Surgery and Technique 2025;10(Suppl 1):S14-S19
This report presents 2 cases of T1–2 disc herniation managed with unilateral biportal endoscopic (UBE) discectomy. Both patients experienced severe arm pain and neurological impairments due to paracentral disc herniations at the T1–2 level, prompting UBE discectomy. The procedures were completed without complications, leading to substantial pain relief and neurological improvement. No symptom recurrence was observed for up to 27 months postoperatively. These cases highlight that, with appropriate indications and refined techniques, UBE discectomy is a feasible and effective surgical approach for T1–2 disc herniation, offering precise visualization and a secure operative field. Further experience and research may solidify the role of this procedure in treating upper thoracic spine lesions.
9.Safety Profile of Biportal Endoscopic Spine Surgery Compared to Conventional Microscopic Approach: A Pooled Analysis of 2 Randomized Controlled Trials
Sang-Min PARK ; Kwang-Sup SONG ; Dae-Woong HAM ; Ho-Joong KIM ; Min-Seok KANG ; Ki-Han YOU ; Choon Keun PARK ; Dong-Keun LEE ; Jin-Sung KIM ; Hong-Jae LEE ; Hyun-Jin PARK
Neurospine 2024;21(4):1190-1198
Objective:
To compare the safety profiles of biportal endoscopic spinal surgery (BESS) and microscopic spinal surgery (MSS) for lumbar disc herniation and spinal stenosis by analyzing the associated adverse events.
Methods:
We pooled data from 2 prospective randomized controlled trials involving 220 patients (110 in each group) who underwent single-level lumbar surgery. Participants aged 20–80 years with radiating pain due to lumbar disc herniation or spinal stenosis were included in this study. Adverse events were recorded and analyzed over a 12-month follow-up period.
Results:
The overall adverse event rates were 9.1% (10 of 110) in the BESS group and 17.3% (19 of 110) in the MSS group, which were not statistically significantly different (p=0.133). Notably, wound dehiscence occurred in 8.2% of MSS cases but in none of the BESS cases. Both groups showed similarly low rates of complications, such as dural tears, epidural hematoma, and nerve root injury. The most common adverse event in the BESS group was recurrent disc herniation (2.7%), whereas that in the MSS group was wound dehiscence (8.2%).
Conclusion
BESS demonstrated a safety profile comparable to that of MSS for the treatment of lumbar disc herniation and spinal stenosis, with a trend towards fewer overall complications. BESS offers particular advantages in terms of reducing wound-related complications. These findings suggest that BESS is a safe alternative to conventional MSS and potentially offers the benefits of a minimally invasive approach without compromising patient safety.
10.Clinical Outcomes and Complications of Unilateral Biportal Endoscopic Posterior Cervical Foraminotomy: A Systematic Review and Meta-Analysis With a Comparison to Full-Endoscopic Posterior Cervical Foraminotomy
Sang Hyub LEE ; Junghan SEO ; Dain JEONG ; Jin Seop HWANG ; Jae-Won JANG ; Yong Eun CHO ; Dong-Geun LEE ; Choon Keun PARK
Neurospine 2024;21(3):807-819
Objective:
The unilateral biportal endoscopic posterior cervical foraminotomy (UBE-PCF) has been recently adopted for unilateral radiating arm pain due to cervical herniated intervertebral disc or foraminal stenosis. We systematically meta-analyzed clinical outcomes and complications of the UBE-PCF and compared them with those of full-endoscopic PCF (FE-PCF).
Methods:
We systematically searched the PubMed, Embase, and Web of Science until February 29, 2024. Clinical outcomes and complications of the UBE-PCF and FE-PCF were collected and analyzed using the fixed-effect or random-effects model. Clinical outcomes of the UBE-PCF were compared with minimal clinically important difference (MCID) following PCF to evaluate the efficacy of UBE-PCF.
Results:
Ten studies were included in the meta-analysis. In the random-effects meta-analysis, the Neck Disability Index (NDI), visual analogue scale (VAS) neck, and VAS arm were significantly decreased after the UBE-PCF (p<0.001). The improvement of NDI, VAS neck, and VAS arm were significantly higher than MCID (p<0.05). The improvement of NDI, VAS neck, and VAS arm were not significantly different between the UBE-PCF and FE-PCF (p>0.05). Overall incidence of complications of the UBE-PCF was 6.2% (24 of 390). The most common complication was dura tear (2.1%, 8 of 390). The incidence in overall complications was not significantly different between the UBE-PCF and FE-PCF (p=0.813).
Conclusion
We found that the UBE-PCF significantly improved clinical outcomes. Regarding clinical outcomes and complications, the UBE-PCF and FE-PCF were not significantly different. Therefore, the UBE-PCF would be an advantageous surgical option comparable to FE-PCF for unilateral radiating arm pain.

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