To begin, prepare for the endoscopic surgery procedure. After inserting a 30 degree endoscope via the viewing channel, insert the surgical instruments and a radiofrequency ablation blade via the working channel to remove the soft tissue on the laminar surface. Remove the soft tissue until the exposure of the lower edge of the L4 lamina, the ligamentum flavum, and the medial edge of the ipsilateral L4-5 facet joint.
This establishes the endoscopic operating space. Then using a 3.5 millimeter high-speed drill operating at 8, 000 rotations per second, remove the ipsilateral lower part of the L4 lamina and the upper part of the L5 lamina. Additionally, use Kerrison Punches to remove the medial inferior facet until the ligamentum flavum is fully mobilized.
Next, separate the ligamentum flavum from the dural sac and gradually remove it from the cranial to the caudal end with Kerrison Punches or forceps. Then carefully remove the medial facet joint of the L4-5 and the hyperplastic facet joint bone with punches, or by using a soft tissue protection drill until the traversing nerve root is completely decompressed. Remove the base of the L4 spinous process with a drill operating at 8, 000 rotations per second and adjust the working channel obliquely toward the contralateral spinal canal.
Undercut the medial part of the contralateral L4 inferior facet. Then fully expose the contralateral ligamentum and remove it using four millimeter Kerrison Punches until adequate dorsal neural decompression. Use a blunt nerve hook to retract and protect the thecal sac and contralateral traversing nerve root or L5.Then expose the contralateral herniated disc fragment.
Then insert forceps or other instruments vertically into the contralateral disc space and remove the herniated disc tissues through the third channel. Finally, use a blunt nerve hook to explore the dural sac and bilateral nerve roots to ensure a sufficient spinal decompression. The T-UBE technique was used for the surgical treatment of lumbar spinal stenosis and left-sided lumbar disc herniation at L4-5.
A comparison of pre and postoperative CT showed adequate bilateral decompression at the L4-5 level. Also, postoperative MRI showed adequate bilateral decompression at the L4-5 level indicating successful removal of the contralateral disc herniation, no compression at the dural nerve, and increased dural sac area. Moreover, the visual analog scale scores pertaining to low-back pain and leg pain were reduced after surgery and throughout the postoperative follow-up.
Similarly, the shifts in Oswestry Disability Index scores reduced post-surgery indicating a successful procedure.
