Full-Endoscopic Decompression Combined with Oblique Lumbar Interbody Fusion for Treating Lumbar Spinal Stenosis with Prolapsed Nucleus Pulposus

Summary

We describe a minimally invasive surgery using a full-endoscopy system to complete the spinal canal decompression visually in oblique lumbar interbody fusion surgery for lumbar spinal stenosis with prolapsed nucleus pulposus.

Abstract

Oblique lumbar interbody fusion (OLIF) has been widely used to treat lumbar spinal stenosis. However, patients with prolapsed nucleus pulposus are not suitable for this surgery. We introduce a hybrid surgical procedure combining OLIF and full-endoscopic spinal canal decompression to address this issue. During the OLIF procedure, after completing the discectomy, the endoscopic system is inserted into the intervertebral space to perform the latter half of the discectomy, remove the loose nucleus pulposus, and achieve direct decompression of the nerve root under visualization. After decompression, the free nerve root can be seen under the endoscopic view. With the assistance of endoscopy, the indications for OLIF surgery can be expanded, allowing for the treatment of cases with sciatica caused by the nucleus pulposus. Intraoperative X-ray fluoroscopy can determine the direction and location of decompression under the endoscopy. All patients experienced satisfactory relief from their lumbar and leg pain after the surgery with no complications. Full-endoscopic decompression combined with oblique lumbar interbody fusion is an effective, safe surgical technique for lumbar spinal stenosis with prolapsed nucleus pulposus.

Introduction

Oblique lumbar interbody fusion (OLIF) has been widely used for the treatment of lumbar spinal stenosis^1,2,3,4. It has many advantages, such as the oblique approach reducing the need for extensive dissection of muscles, ligaments, and nerves, large interbody cages, and extensive bone grafting, leading to higher fusion rates and more durable outcomes^4,5,6. However, due to the technical principle of tightening the ligament to achieve indirect decompression, patients with prolapsed nucleus pulposus are not suitable for this surgery^3,5,7.

For patients without compromised spinal stability, full-endoscopic decompression surgery can effectively relieve the nerve to achieve satisfactory clinical outcomes^8,9,10. The magnified and illuminated view can help the surgeon achieve a direct decompression. However, endoscopic decompression surgery is not appropriate for cases with preoperative spinal instability^8,11.

Based on the strengths and weaknesses of the two surgeries, we introduce a hybrid minimally invasive surgery that combines OLIF with full-endoscopic spinal decompression for the treatment of lumbar spinal stenosis patients for whom direct decompression is necessary. The prolapsed nucleus pulposus can be completely removed without neurological complications. The clinical outcome is satisfactory.

Protocol

This study has been approved by the Ethics Committee of Hebei General Hospital. Informed consent has been obtained from all individual participants.

NOTE: A flow diagram of full-endoscopic decompression combined with OLIF surgery is shown in Figure 1.

1. Preoperative preparation (Radiographic study)

1. Determine the surgical segment for the patient according to the physical examination and radiological study.Use the imaging evaluation to locate the herniated disc, determine the height of the intervertebral space, and check whether there is calcification (Figure 2).
2. Measure the window between the psoas major muscle and the artery to ensure sufficient width for the operation space and to find whether there are anatomical variations (Figure 3).

2. Position and skin marking

1. Place the patient in a lateral (usually left side above) decubitus position to allow access to the lumbar spine after general anesthesia. Achieve the pelvis traction by bending the surgical bed to enlarge the operation space.
2. Secure the patient's thorax and pelvis to the operating table with wide tape, and position the hips in flexion to relax the psoas major muscle and lumbar plexus nerves (Figure 4).
3. Use a fluoroscope to determine the center point of the intervertebral disc in the lateral position. Make a marking on the skin. Mark the contour of the iliac wing on the skin surface (Figure 5).

3. Approach and exposure

1. Make the surgical incision approximately 4 cm long, 3 cm anterior to the center of the disc (Figure 6). Bluntly dissect the three layers of abdominal muscles successively along the direction of the muscle fibers, namely the external oblique muscle, the internal oblique muscle, and the transversalis muscle (Figure 7).
2. Expose the retraperitoneal fat to the surgical field. Bluntly dissect these fats to expose the anterior border of the psoas (Figure 8). Retract the anterior border of the psoas posteriorly using the Cobb dissector to expose the surface of the disc (Figure 9).
3. Nail two Kirschner wires into the proximal and distal vertebral bodies of the intervertebral disc. Block the psoas muscle on the dorsal side. Expose the lateral side of the intervertebral disc and vertebral body clearly (Figure 10).

4. Discectomy and decompression

1. Incise the annulus fibrosus of the disc with a 10-blade scalpel. Remove the degenerated disc material from the intervertebral space using the forceps and reamer (Figure 11).
2. Insert the endoscope system into the intervertebral space (Figure 12). Perform the surgical procedure under continuous saline irrigation. Saline can freely overflow from the skin incision. Control the flow rate of water by the height of the saline bag.
3. Remove the posterior portion of the intervertebral disc material under direct endoscopic visualization. The spinal canal is located at the 12 o'clock position in the visual, the right annulus fibrosus is at the 6 o'clock position, and the endplates are located at the 9 o'clock and 3 o'clock positions, respectively (Figure 13).
4. Perform spinal canal decompression carefully from the inside of the disc to the outside. Use graspers, forceps, and the probe for this. It is easier to decompress the right lateral recess than the left due to the limited tilting angle of the endoscope.
5. Use a diamond burr in decompression when there are osteophytes on the posterior edge of the vertebral body or when the intervertebral disc is calcified (Figure 14). Ensure the decompressed nerve root is clearly seen under the endoscope (Figure 15). Visualize the position of the forceps by X-ray fluoroscopy to confirm the adequacy of decompression (Figure 16).
   NOTE: The complete removal of the nucleus pulposus during surgery and the direct visualization, wider, and more direct decompression of the spinal canal are key factors for postoperative neurological function recovery.

5. Interbody fusion and instrumentation

1. After spinal canal decompression, remove the endoscope system.
2. Perform the next steps under direct visualization: First, penetrate the contralateral annulus fibrosus using a reamer. Insert a peek cage filled with artificial bone and recombinant human bone morphogenetic protein-2 (rhBMP-2) vertically into the intervertebral space. Confirm the location and size of the cage by X-ray fluoroscopy.
3. Insert two 7 mm diameter screws into the vertebral bodies on the cephalic and caudal sides. Use a rod to connect the two screws together (Figure 17).
4. After careful hemostasis and irrigation of the surgical field, suture the incision layer by layer and place a drainage tube in the surgical area (Figure 18).

6. Postoperative care

1. The patient can get out of bed with a brace 24 h after the operation. Remove the drainage tube when the drainage volume is less than 50 mL/24 h.

Results

From December 2023 to October 2024, this surgery was performed on 8 patients in our hospital, including 5 males and 3 females aged 44-78 years with an average of 67.9 years. The average operation time was 135.8 min.

Patients presented relief of their symptoms including Intermittent claudication and sciatica. The neurological function on each follow-up greatly improved compared with that before surgery.

Discussion

This surgery alleviates symptoms caused by both spinal stenosis and prolapsed nucleus pulposus, resulting in satisfactory clinical outcomes for the patients. The satisfactory clinical outcomes are attributed to the direct decompression of the spinal canal under the endoscopy, which differs from the traditional OLIF surgery where spinal canal decompression relies on the tension of the posterior longitudinal ligament after increasing the intervertebral height^4,6

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Artificial bone	Sichuan Guona Technology Co.,LTD	NNBP/40D	4 mm × 4 mm × 20 mm
Endoscope system	SPINENDOS GmbH	SP081430.030	Inner diameter: 4.3 mm; Outer diameter:7.0 mm; Field angle: 80°; Visual angle: 30°; Working length: 181 mm.
Endoscopic forceps	SPINENDOS GmbH	SP082781.835	Φ2.5 mm × 330 mm
Endoscopic hook	SPINENDOS GmbH	SP082628.351	Φ2.5 mm × 310 mm
High-speed burr	XISHAN	LB29035J.DS	Φ3.5 mm × 310 mm
Interventional radiology	ELLIQUENCE	DTF-40	40 cm
Peek cage	Bonovo	O-FUSE	50 mm × 18 mm ×13 mm
rhBMP-2	Jiuyuan Gene Engineering Co., Ltd	rhBMP-2	1.0 mg
Screws	Ruihe Medical	F0-05	Φ7.0 mm × 45 mm