Biportal Endoscopic Spine Surgery for Epidural Metastatic Tumors: A Surgical Technical Note With a Case Series

Chan Yang Noh; Il Choi; Junsoo Jang

doi:10.21182/jmisst.2025.02593

Abstract

Endoscopic spine surgery has rapidly evolved as a minimally invasive technique for treating various spinal pathologies. However, its use in removing epidural metastatic tumors remains insufficiently explored. This video article presents 2 cases utilizing unilateral biportal endoscopic spine surgery for resection of epidural metastatic tumors causing spinal cord compression. The first case involved a 63-year-old woman with metastatic non-small cell lung cancer at T4–5, and the second case an 86-year-old man with prostate cancer metastases at T6–9. Both patients presented with motor weakness (American Spinal Injury Association [ASIA] grade C) and potential spinal instability (SINS [Spinal Instability Neoplastic Scale] score 7). The surgical techniques emphasized precise identification and dissection of the tumor–dura interface to minimize dural injury and bleeding—an essential consideration when managing vascular lesions, particularly under antiplatelet therapy. Both cases achieved complete tumor resection with minimal blood loss (60–90 mL) and operative times of 71 and 109 minutes, respectively. Postoperatively, both patients improved to ASIA grade D and began early radiotherapy, underscoring the advantages of this minimally invasive approach in enabling prompt adjuvant treatment. Endoscopic epidural tumor removal represents a safe and less invasive alternative to open surgery for selected patients, though further long-term evaluation is warranted.

Key Words: Neoplasm metastasis, Spinal diseases, Vertebra

WRITTEN TRANSCRIPT

0:03 Introduction: Roles of Endoscopic Spine Surgery

In recent trend, endoscopic spine surgery has evolved exponentially and has been proven to be a safe and efficient surgical modality along with minimally invasive spine surgery [1]. Development of instruments and techniques of endoscopic spine surgery allows spinal surgeons to approach and address various types of spinal diseases including spinal stenosis, herniated disc, and ossification of ligamentum flavum. However, the feasibility of endoscopic spine surgery for other disease entities such as various types of tumors is still a topic of debate [2,3]. In an effort to expand the scope of endoscopic spine surgery, this video article aims to discuss the role of biportal endoscopic spine surgery for epidural metastatic tumors with 2 cases.

0:40 Case Presentation

A 63-year-old female with a history of stage IV non-small cell lung cancer with previous chemotherapy and spine radiotherapy history was referred for motor weakness of lower limbs. The results of neurologic and physical examination are shown on the slide.

0:55 Preoperative Computed Tomography

The preoperative computed tomography (CT) scan showed osteolytic lesion of T4 vertebral body and high density lesion in spinal canal at T4–5 level.

1:04 Preoperative Magnetic Resonance Imaging

The preoperative magnetic resonance imaging (MRI) showed a cord-compressing, enhancing epidural lesion in the dorsal aspect of the spinal cord at the T4–5 level.

1:12 Intraoperative Footage

Unilateral biportal endoscopic approach for epidural tumor removal was performed.

1:17 Docking Point

Docking point was made at T4 lamina and spinolaminar junction of T4 was exposed.

1:24 Hemilaminectomy

Right hemilaminectomy of T4 lamina was performed using high-speed drill.

1:32 Dissection of Ligamentum Flavum

After sufficient laminectomy, the midline cleft of ligamentum flavum was located as an anatomical landmark using a ball-tip hook, the ligamentum flavum was dissected from the midline to expose the epidural space.

1:47 Locating Epidural Tumor

The epidural tumor was observed to be avascular and fibrotic. This may be the post-irradiation change from radiotherapy.

1:53 Dissection Plane

The dissection plane between the tumor and dura was found and explored. Along the dissected plane between the tumor and dura, tumor in contralateral dorsal aspect was removed.

2:05 Removal of Epidural Tumor

After creating enough space, epidural tumor was resected further.

2:08 Additional Laminectomy

Upper lamina of T5 was additionally drilled to expose the full extent of epidural tumor.

2:24 Removal of Epidural Tumor

After exposure, tumor resection at ipsilateral epidural space was performed.

2:32 Dissection Plane

To ensure the dissection plane double-end freer is used. This repeated effort to find the dissection plane is crucial technique to minimize dural injury and tumor bleeding.

2:44 Insertion of Drain Catheter

After confirming the total resection of targeted epidural tumor, a drain catheter is inserted to conclude the operation.

2:50 Postoperative Imaging

The postoperative CT scan and MRI showed sufficient decompression and complete resection of epidural tumor without radiographic evidence of spinal cord compression.

3:01 Operation Summary and Postoperative State

The intraoperative blood loss was 60ml and the operation time lasted 71 minutes. After 9 postoperative days, the patient recovered from American Spinal Injury Association (ASIA) grade C to grade D and the patient was started on radiotherapy for local control.

3:17 Case Presentation

The next case is an 86-year-old male patient with incidental finding of prostate cancer with multiple metastases. The patient was on dual antiplatelet agents after percutaneous coronary intervention. The motor grades in physical examination are shown in the table and the patient was evaluated as ASIA grade C. Preoperative imaging showed potential instability with SINS (Spinal Instability Neoplastic Scale) score of 7, with the approximate life expectancy of 12 months.

3:46 Preoperative Imaging

The preoperative CT scan and MRI showed enhancing lesion compressing spinal cord in the dorsal aspect of T 6-7-8.

3:55 Intraoperative Footage

Unilateral biportal endoscopic approach for epidural tumor removal was performed.

4:05 Docking Point and Laminectomy

After docking and exposing spinolaminar junction at left T8 lamina, hemilaminectomy was performed with high-speed drill.

4:18 Manipulation of Ligamentum Flavum

The midline cleft of ligamentum flavum was located as an anatomical landmark. After dissection, ligamentum flavum was removed to expose the epidural space.

4:37 Locating Epidural Tumor

Epidural tumor was located and the dissection plane between the tumor and dura was identified and dissected.

4:57 Additional Laminectomy

At left T9 lamina, hemilaminectomy was performed with high-speed drill.

5:02 Epidural Tumor Dissection

After removing the ligamentum flavum, dissection plane was once again identified and dissected to separate the tumor. The tumor contained hemorrhagic portion and shows high vascularity. This might be due to the antiplatelet agents. The effort to find the dissection plane is the cornerstone of endoscopic epidural tumor removal, especially in such case with high bleeding risk.

5:59 Removal of Epidural Tumor

After careful dissection, tumor removal is achieved. After confirming the total resection of targeted epidural tumor, a drain catheter is inserted to conclude the operation. Despite careful hemostatic procedures, the patient underwent endoscopic hematoma irrigation in postoperative day 1.

6:19 Postoperative Imaging

After endoscopic hematoma irrigation, the postoperative CT scan and MRI showed sufficient decompression and complete resection of epidural tumor without radiographic evidence of spinal cord compression.

6:32 Summary of Operation and Postoperative State

The intraoperative blood loss was 90 mL with the operation time lasting 109 minutes. After 7 postoperative days, the patient recovered from ASIA grade C to grade D and the patient was started on radiotherapy for local control.

6:48 Discussion

Endoscopic epidural tumor removal enables early radiotherapy by facilitating separation surgery and requires shorter time for wound healing due to its minimally invasive characteristic. In contrast to conventional open surgery requiring 2 weeks delay of radiotherapy for wound healing [4,5], more immediate postoperative radiotherapy in endoscopic epidural tumor removal may be clinically beneficial for local control of metastatic patients [6]. Although useful, endoscopic epidural tumor removal has narrow indication such as low instability and needs longer follow-up data to support its safety.

7:22 Conclusion

In conclusion, endoscopic spine surgery may be suggested as a viable option for epidural metastatic spinal tumor. In addition, identifying and manipulating the dissection plane between the metastatic lesion and dura is a technique of utmost importance in endoscopic epidural tumor removal along with meticulous hemostatic procedures.