Hybrid Unilateral Biportal Endoscopy-Unilateral Laminotomy for Bilateral Decompression/Percutaneous Endoscopic Lumbar Discectomy Surgery for the Treatment of Multilevel Lumbar Spine Pathology

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J Minim Invasive Spine Surg Tech. 2025;10(Suppl 2):S306-S314

Publication date (electronic) : 2025 July 31

doi : https://doi.org/10.21182/jmisst.2024.01893

Kang Suk Moon^,1, Pedro Leonardo Villanueva-Solorzano¹, Chung Nam Lee¹, Sung Sik Park²

¹Department of Neurosurgery, Ileona Hospital, Spine Center, Siheung, Korea

²Department of Orthopedic Surgery, Ileona Hospital, Joint Center, Siheung, Korea

Corresponding Author: Kang Suk Moon Department of Neurosurgery, Ileona Hospital, Spine Center, 472, Hwanggogae-ro, Siheung 14996, Korea Email: nsdrmoonks@gmail.com

Received 2024 November 2; Revised 2025 March 2; Accepted 2025 April 29.

Abstract

INTRODUCTION

Recurrent lumbar disc herniation (rLDH) occurs in approximately 5%–15% of patients following primary discectomy, with 20%–30% of these patients also presenting with concurrent lumbar spinal stenosis (LSS) [1]. Traditional treatment options for rLDH typically involve rediscectomy and spinal fusion—more extensive and invasive procedures. Many surgeons favor larger surgeries or fusion, both of which are associated with higher complication rates and significantly longer recovery periods [2].

The coexistence of multiple pathologies at different levels, adds complexity to the decision-making process when determining the most appropriate surgical approach. However, advances in endoscopic techniques and equipment in recent years have expanded the application of these procedures to effectively address various spinal pathologies. These techniques offer enhanced visualization, comparable clinical outcomes, and reduced postoperative pain compared to traditional methods [3].

This report presents 2 cases of patients with compound lumbar spine pathologies treated simultaneously through endoscopy in a single operative session. To our knowledge, this is the first technical report describing a hybrid endoscopic approach to treat complex, multilevel pathologies such as LSS and recurrent disc herniation.

CASE PRESENTATION

1. Case 1

A 64-year-old female who underwent a right-sided laminectomy at the L4–5 level for a disc rupture 3 years prior, complained of progressive lower back pain and neurogenic claudication. Magnetic resonance imaging (MRI) demonstrated severe LSS at the L3–4 level and ipsilateral disc herniation recurrence at the L4–5 level, with major calcification (Figure 1).

Figure 1.

Case 1 preoperative images. Sagittal (A) and axial T2-weighted (B, C) magnetic resonance imaging (MRI) scans demonstrate narrowing of the spinal canal at L3–4 and recurrent disc herniation with clear compression of the thecal sac at the L4–5 lateral recess. (D) Sagittal computed tomography (CT) image highlights a calcified disc component associated with recurrent lumbar disc herniation and endplate changes at L4–5 (arrow). (E) An axial CT scan at the L4–5 level; the red asterisk (*) indicates a portion of the calcified disc herniation, further illustrating the anatomical compression consistent with MRI findings.

2. Case 2

A 68-year-old female who had a prior interspinous device implantation and decompression at L4–5 level 12 years ago, presented with left-sided hip pain and progressive lower back discomfort. MRI revealed LSS at the L3–4 level with mild listhesis and recurrent disc herniation on the left lateral recess at L4–5. Her symptoms worsened 4 months ago, despite multiple pain management interventions, which provided no significant relief (Figure 2).

Figure 2.

Case 2 preoperative images. (A) Sagittal T2-weighted magnetic resonance imaging (MRI) scan; a red asterisk (*) indicates the recurrent lumbar disc herniation compressing adjacent structures in the lateral recess area. (B) Axial T2-weighted MRI at L3–4 shows severe stenosis. (C) Axial T2-weighted MRI at L4–5; the red asterisk (*) indicates the area of disc herniation at L4–5. (D) Three-dimensional computed tomography (CT) reconstruction and sagittal CT scan of the lumbar spine provide detailed visualization of bony anatomy, the location of an interspinous device, and evidence of mild listhesis at L3–4. (E) Axial MRI magnified images from 2 adjacent slices at L4–5 offer detailed insights into pathological changes in this region (red circle).

Given the presence of an interspinous process device—which is an obstacle for a posterior approach and the lateral recess location—a percutaneous endoscopic lumbar discectomy (PELD) approach at L4–5 offered more direct ventral access to the herniated fragment, reduced the need to dissect scarred posterior tissues, and decreased the morbidity ofadhesiolysis and the risk of dural tear. Although unilateral laminotomy for bilateral decompression (ULBD) alone might suffice in certain cases, we elected PELD to provide more targeted decompression for the recurrent adhered fragment.

A staged unilateral biportal endoscopy (UBE)-ULBD was performed to treat the LSS followed by PELD to treat the rLDH. A critical step in the procedure for case 1 involved removal of the calcified component of the disc, which required extensive drilling (Figure 3). In case 2, resecting the extensive dural adhesions was essential to achieve complete decompression. Postoperative MRIs taken one day after surgery confirmed successful results in both cases (Figures 4 and 5). The patients were discharged and remained pain-free, with independent ambulation restored at 6-month and 1-year follow-up (Figure 6).

Figure 3.

Case 1 intraoperative images at the L4–5 level. (A) Endoscopic view during percutaneous endoscopic lumbar discectomy illustrates the surgical field orientation with different compartments and critical anatomical elements visible during the procedure. The primary area of soft disc material removal is indicated with a red asterisk (*). (B) Close-up view of the calcified disc component of the recurrent lumbar disc herniation. (C) Demonstration of using a high-speed drill to remove the calcified component of the herniated disc, a crucial step to relieve neural compression.

Figure 4.

Case 1 postoperative imaging, setup, and incisions. Sagittal (A) and axial T2-weighted (B, C) magnetic resonance imaging images show adequate bilateral decompression at the L3–4 level and clear decompression of the thecal sac at the L4–5 left lateral recess. (D, E) Sagittal and axial computed tomography scans demonstrate successful removal of the major calcified disc component (arrow and asterisk, respectively) at L4–5. (F) A photograph shows surgical incision sites and placement of drainage tubes immediately after surgery, used to manage postoperative bleeding and prevent fluid accumulation. (G) Healed surgical incision sites at 10-day follow-up.

Figure 5.

Case 2 postoperative imaging, incisions, and control anteroposterior (AP) fluoroscopy for reference. (A) Sagittal T2-weighted magnetic resonance imaging (MRI) image (red asterisk [*] indicates site of decompression for recurrent lumbar disc herniation) and (B, C) axial T2-weighted MRI scans confirm successful decompression at both levels, with postoperative changes and no evident compression of the thecal sac at the L4–5 lateral recess (yellow dotted circle). (D) A photograph shows healed surgical incision sites after hybrid unilateral biportal endoscopic laminotomy with bilateral decompression and percutaneous endoscopic lumbar discectomy surgery. Postoperative AP x-ray (E) and lateral radiographs (F) at 6-month and 1-year follow-ups demonstrate preserved segmental motion, minimal translation, and preservation of facet joint elements with minimal bone disruption. Informed consent was obtained frome the patients for publication of this case and the accompanying images.

Figure 6.

Postoperative lateral radiographs for cases 1 and 2. (A–C) Case 1 postoperative (post-op) radiographs at immediate, 6-month (6 Mo), and 1-year (1 Y) follow-ups, respectively, demonstrate stability at L3–4 and L4–5. (D–F) Corresponding radiographs for case 2 at the same postoperative intervals, illustrating stable spinal instrumentation. Notably, neither case shows evidence of recurrent disc herniation or hardware complications.

SURGICAL TECHNIQUE

In our practice, the majority of UBE-ULBD and PELD procedures are performed under intravenous sedation, which is associated with fewer complications than general anesthesia since it obviates the need for endotracheal intubation or oral sedatives. Nevertheless, the final choice of anesthetic approach is determined by patient comorbidities and the clinical judgment of the surgical team.

A UBE procedure with ULBD was initially performed to address the stenosis, followed by a PELD for the recurrent disc herniation level, for both cases.

Two small incisions were made: one for the insertion of the endoscope and irrigation pump, and the other for instrument insertion and saline outflow. The spinolaminar junction is exposed, subsequently a high-speed diamond burr is used to resect part of the facet and lamina, followed by the detachment of the ligamentum flavum (LF) from its insertions. For bilateral decompression, the "over-the-top" (sublaminar) technique is applied, resecting part of the facet and LF on the contralateral side until the contralateral nerve root is exposed (Figure 7). The nerve roots and thecal sac are clearly visualized, with the pulsatility of the thecal sac appreciated, which confirms adequate decompression. This stage concluded by closing the portals with a 3–0 nylon suture.

Figure 7.

Case 2 intraoperative images at the L3–4 level: endoscopic technique sequence for sublaminar dissection and contralateral exposure. (A) Initial dissection of the sublaminar space for bilateral decompression. (B) Application of the "over-the-top" (sublaminar) technique. (C, D) Partial resection of the facet joint and LF on the contralateral side using a high-speed drill, Kerrison rongeurs, and dissectors until the contralateral nerve root is visualized. (E) Exposure of the contralateral traversing nerve root (marked by a white asterisk) and clearly visualized thecal sac and surrounding structures, with drain placement after decompression.

Following this, a PELD was performed through a transforaminal approach. A fluoroscopy-guided skin incision was made, after which a guide wire, dilator, and working port were inserted into the disc space. This was followed by the introduction of the endoscopic scope to allow for visualization and treatment of the affected area. This approach is preferred for its direct access to the ventral aspect of the dura, enabling thorough removal of herniated disc, adhesions, and calcified components, whereas the posterior approach is less effective and often results in incomplete decompression. This underscores the superiority of the transforaminal approach in achieving optimal outcomes in such cases (Figure 8).

Figure 8.

Surgical incision planning for hybrid UBE-ULBD/PELD surgery. (A) A schematic diagram illustrates the key anatomical landmarks, incision placement, and measurement guidelines for the left-sided surgical approach. (B) Three-dimensional computed tomography reconstruction from case 1 depicts a detailed incision planning for a right-sided surgical approach. The blue asterisk (*) indicates the previous laminotomy site, and the red circle highlights the spinolaminar junction. UBE-ULBD/PELD, unilateral biportal endoscopic laminotomy with bilateral decompression and percutaneous endoscopic lumbar discectomy. UBE-ULBD/PELD, unilateral biportal endoscopy-unilateral laminotomy for bilateral decompression/percutaneous endoscopic lumbar discectomy.

This sequential combination of UBE-ULBD and PELD not only treats both pathologies efficiently but also minimizes patient recovery time by allowing 2 adjacent-level conditions to be addressed in a single surgical session. In the operating suite, the transition time between UBE-ULBD and PELD is minimal because the patient’s position remains unchanged, as does the fluoroscopic guidance, endoscopic tower, monitor, and equipment. Overall, the procedure had an average duration of 80 minutes.

DISCUSSION

Management strategies for rLDH typically involve rediscectomy and/or spinal fusion, depending on the patient's symptoms, the presence of spinal deformity, and the risk of instability [4]. With precise MRI-based planning, these procedures can be targeted accurately, ensuring minimal disruption to the surrounding tissues [5].

There are 2 main endoscopic approaches used to treat lumbar spine pathologies: Transforaminal and Interlaminar [3]. The transforaminal approach is generally chosen for paracentral and central soft disc herniations (LDH), lumbar radiculopathy, and foraminal or extraforaminal herniations. With advancements in technology, this approach has been implemented in more complex cases, including highly migrated, far-lateral rLDH and disc calcifications [6]. In contrast, the interlaminar approach is preferred for treating paracentral or central disc herniations, with or without disc migration, and for decompressing central or lateral recess spinal canal stenosis [7]. The anatomical distinctions between these approaches are key to understanding the variability in postoperative outcomes.

The PELD procedure is a minimally invasive alternative to fusion surgery that offers significant advantages by accessing the spine without disturbing previously manipulated tissues, reducing the risk of complications like dural fistula formation [8]. Despite its less invasive nature, PELD provides adequate exposure to treat complex disc pathologies, such as extensive disc migrations and calcified fragments, while ensuring effective decompression with minimal tissue damage and fewer postoperative complications [9].

Additionally, the continuous irrigation system in endoscopic procedures is crucial for keeping the surgical field clear, controlling bleeding, minimizing epidural pressure, and lowering the risk of infection, ultimately resulting in better surgical outcomes [10].

Performing staged, minimally invasive endoscopic procedures for rLDH and LSS at adjacent levels has shown both feasibility and effectiveness [11]. Although these methods are not yet universally adopted as alternatives to open surgery, they offer substantial benefits, including reduced blood loss, diminished postoperative pain, shorter hospital stays, minimal tissue dissection, decreased muscle trauma, faster recovery, and a lower infection risk. In cases with significant scarring or adhesions, careful, stepwise adhesiolysis under constant irrigation and endoscopic magnification helps mitigate dural injury [12].

In cases of severe scarring or adhesions, careful and gradual adhesiolysis under continuous irrigation and endoscopic magnification is employed to minimize the risk of dural injury, and preoperative imaging—particularly CT scans—is critical for accurate planning. Strategies for immediate repair or conversion to open surgery must also be in place to manage potential complications such as dural tears. Additional measures to reduce dural tear risk include using fine burrs, blunt dissection, and fibrin sealants for any micro-leaks. From a training perspective, a structured curriculum featuring cadaveric workshops, simulation, and mentorship by experienced endoscopic surgeons is essential for mastering both UBE and PELD. Finally, institutions and professional societies should collaborate to develop credentialing guidelines that ensure surgeon proficiency and uphold patient safety, particularly for complex hybrid procedures.

While these initial cases underscore the potential of the hybrid UBE-ULBD/PELD approach for managing complex, multilevel lumbar pathologies, larger prospective trials with control groups remain essential to confirm these findings. Long-term data are limited, emphasizing the need for dynamic radiographic assessments and extended follow-up to evaluate recurrence rates, complications, and durability. Our institution has adopted a standardized extended follow-up schedule with periodic clinical and imaging evaluations to rigorously track patient outcomes. Ultimately, future multicenter, prospective studies with larger cohorts are vital for refining patient selection, establishing standardized protocols, and validating the long-term benefits of combining UBE-ULBD and PELD in challenging lumbar spine conditions.

CONCLUSION

The use of simultaneous endoscopic techniques, as demonstrated in these cases, offers a viable and efficient alternative to traditional open surgeries for complex lumbar spine pathologies, enabling surgeons to address multilevel conditions simultaneously by combining procedures like UBE-ULBD and PELD, with the advantages previously outlined. Clinical outcomes in spinal surgery are significantly influenced by the complexity of the pathology and the surgeon’s expertise, highlighting the importance of refined technical skills and precise preoperative planning for the successful application of minimally invasive techniques. Additionally, from a practical standpoint, employing 2 endoscopic modalities in a single operation requires familiarity with both systems but remains feasible in a well-equipped setting. This underscores the need for specialized training in endoscopic spine surgery to ensure surgeons acquire the necessary skills to adopt and refine these hybrid methods. As these techniques evolve, their potential to serve as alternatives to more invasive procedures will continue to expand, further improving patient outcomes and minimizing recovery time.

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