V-shape Bichannel Endoscopy System (VBE)

V-shaped dual-channel endoscopic lumbar fusion (Transforminal VBE-LIF)

Preoperative preparation and planning: Before surgery, we need to carefully ask the patient's medical history, physical examination and auxiliary examination to clarify the patient's diagnosis, and exclude the relevant contraindications before considering the appropriateness of choosing VBE surgery. Before surgery, X-rays should be carefully read to analyze the vertebral rotation, scoliosis, joint hyperplasia, and the presence or absence of migrated vertebrae and other spinal degeneration. The height of the intervertebral space, the size and height of the intervertebral foramen, and the small joints of the diseased intervertebral space should be observed through the lateral radiographs, and the 3D morphology of the foramen and lumbar spine can be observed through the 3D reconstruction of the CT, and the lumbar spine should be analyzed carefully by the lumbar spine magnetic resonance sagittal and transverse scans, to observe the presence or absence of the nerve root degeneration of the operated segment, and to understand the nerve root alignment. We carefully analyze the lumbar MRI sagittal and transverse scans to see if the nerve roots in the operated segment have any variations, to grasp the nerve root course, and to plan the surgical path and precautions to avoid nerve damage. According to the planned surgical path, the paracentesis distance and angle of the puncture are measured on the lumbar magnetic resonance film. Generally, the paracentesis distance of the lumbar VBE is 6 to 9 cm, and the more cephalad, the smaller the paracentesis distance is, and the abduction angle is generally 30° to 45°.

Body position and incision marking: the patient adopts the prone position, the abdomen is suspended, and the hospitals that have the conditions can use neurophysiological monitoring to mark the body positioning of the pedicle screws and the position of the dual-channel endoscopic incision with the body surface locator. Routinely disinfect and spread the towel, because the dual-channel endoscopy needs two ways of flushing water, flushing water is more, need to prepare about 3000 ml of flushing water, and at the same time to warm the flushing water, to avoid excessive flushing water to affect the patient's body temperature, the use of arthroscopic water bag to collect irrigation fluid, the position of the C-arm X-ray machine and the position of the imaging equipment planned in advance, to facilitate the surgical operation and fluoroscopy, to avoid the repeated adjustments delayed surgical time.

Placement of guidewire for percutaneous pedicle screws: Generally, the guidewire for the segment to be fixed with percutaneous pedicle screws is first implanted under fluoroscopy, but it can also be done endoscopically first.

However, it is also possible to perform endoscopic fusion followed by percutaneous pedicle screw guidewire implantation and fixation.

Needle puncture: Specialized blunt and pointed needles are available as part of the instrumentation and can be selected according to the surgeon's preferences. The optimal puncture path is along the superior endplate of the inferior vertebral body, close to the lateral border of the calcaneus at about 45°. The superior and lateral deviation tends to injure the outlet root, while the medial deviation tends to injure the dural sac and the walking root. Therefore, preoperative planning of the preoperative path should be performed by carefully reading the imaging data and

Determine the optimal puncture path.

Establishment of the working channel: Once the position of the puncture needle is satisfactory, the corresponding dilatation tube is used to carry out step-by-step dilatation. After completion of the dilatation, the working channel with the inserted core is inserted along with the puncture needle to reach the satisfactory position. The plain circular saw is then sawed into the articular synovial joint from within the channel under direct vision or fluoroscopy. Once the circular saw has reached the deepest safe position, the bone block is removed and retained for bone grafting.

Intervertebral space treatment: After the bone block is removed by the circular saw and gun pliers, the intervertebral space can be reached directly, the nucleus pulposus is removed with the nucleus pulposus forceps, the intervertebral space spreader is spread step by step, and the intervertebral space reamer and spatula are used to deal with the endplates until they bleed out and are well-protected. The current design of the VEB microscopic tool is depth-limited, with the deepest entry into the intervertebral space not exceeding 40 mm, which ensures that blood vessels and organs anterior to the vertebral body are not injured.

Bone graft fusion: After the intervertebral space has been satisfactorily treated, a bone graft funnel is inserted into the intervertebral space for bone grafting. Intervertebral bone grafting needs to ensure that the amount of bone grafted is sufficient, and often, the resected autogenous bone of the articular eminence does not have the amount of bone needed for fusion, so it is necessary to implant enough allogeneic or artificial bone as a replacement material, or to use materials that promote bone formation, such as BMPs, in order to ensure that the grafted bone achieves fusion.

Implantation of the fusion device: After bone grafting, the fusion device is implanted. With VBE dual access, the entire fusion implantation process can be performed under endoscopic surveillance. The fusion devices currently used are available in both fixed and braced sizes. Braced fusion devices are easier to implant endoscopically due to their smaller size and can be braced after the fusion device has been implanted in place.

Ipsilateral and contralateral decompression: It is generally recommended that decompression be performed after fusion implantation has been completed, which can be done directly with the fused dual-channel instrumentation without replacing the dual-channel working trocar. If the field of view is not very clear due to bleeding, etc., the conventional intervertebral foramen can be replaced to perform decompression and disc removal; if there is still a herniated or stenotic disc on the contralateral side, conventional intervertebral foramen can be used on the contralateral side for decompression, removal of the nucleus pulposus, and removal of the nucleus pulposus. Nucleus pulposus can be removed on the contralateral side if there is still disc herniation or stenosis, and both sides can be operated by two operators at the same time, which does not increase the operation time.

Percutaneous screw fixation: After completion of fusion and decompression, percutaneous pedicle screw fixation is performed. After fluoroscopy and confirmation, the percutaneous screws are screwed in along the placed guidewire and the incision is closed.