biportal endoscopic surgery for lumbar spinal stenosis with contralateral disc herniation

A 3-Channel Endoscopic Technique for Lumbar Stenosis and Contralateral Herniation

In the field of spine surgery, minimally invasive spine surgical (MISS) techniques have evolved significantly in recent years, transitioning from open surgery to microscopic, microendoscopic, and endoscopic surgery. Endoscopic spine surgery is an advanced form of MISS technique that has been widely used to treat spinal diseases and achieve satisfactory clinical outcomes1. Compared with traditional open surgery, it has the advantages of less tissue damage, less bleeding, quicker recovery, and fewer postoperative complications2. 
Endoscopic spine surgery can be performed using single or two portals. Unilateral biportal endoscopic (UBE) spine surgery is an innovative type of MISS technique that was first reported for performing lumbar discectomy in Argentina. It has since been refined to also perform decompression or fusion surgery in South Korea3. The surgical procedure of the UBE technique is similar to conventional open surgery. However, the UBE technique is less invasive and provides a clearer field of view compared to traditional open surgery4,5. 
The conventional UBE technique not only enables unilateral decompression but also achieves bilateral decompression for spinal stenosis6,7. In 2019, Heo et al.8 reported that the UBE technique could significantly expand the stenotic dural areas through unilateral laminotomy for bilateral decompression (ULBD). This technique also preserved more of the ipsilateral facet joint by undercutting the medial facet joint, compared to conventional microscopic decompression. In 2021, Kim et al.9 described a new decompression procedure for UBE in cases of asymmetric spinal stenosis using a contralateral approach. The contralateral approach UBE technique was able to achieve adequate decompression of the contralateral recess and spinal stenosis. It had advantages such as better manipulative freedom, a more accessible target approach, and more facet preservation.
The advantage of the UBE technique is dorsal and lateral spinal decompression through the endoscopic ULBD procedure. However, It is challenging to perform ventral neural decompression or discectomy when there is bilateral recess stenosis or disc herniation. Although bilateral UBE can be performed, it will significantly prolong the operation time, increase intraoperative bleeding, and elevate the risk of dural injury. Here, a third channel was developed in the UBE technique to perform the discectomy within the same endoscopic field of view. This allows the instruments to be inserted vertically into opposite discs, making the discectomy process easier. This technique can not only achieve adequate decompression of the bilateral spinal canal but also effectively remove contralateral herniated disc fragments.

Author Spotlight: Unveiling the Potential of TUBE Technique in Spinal Surgery

The Third Channel-Assisted Unilateral Biportal Endoscopic Technique for Lumbar Spinal Stenosis Combined with Contralateral Disc Herniation

Our research focuses on unilateral bipolar endoscopy UBE for spinal degenerated diseases. The traditional UBE technique with two porters on one side can achieve unilateral laminectomy for bilateral decompression, ULBD, and therefore show favorable clinical outcomes. Here we try to improve this technique to make it more efficient and safer.The UBE technique has been increasingly used in spinal decompression or discectomy as a new endoscopic technique. The UBE technique recently has been proved to offer similar clinical outcomes compared to microdiscectomy by two randomized controlled trials. High resolution spinal endoscopes, as well as some special surgical tools suitable for endoscopic surgery, including operating tools and radial frequency abrasion tools have accelerated the development of spinal endoscopic surgery.Besides navigation techniques are also helpful to arrange spinal endoscopic surgery. For the conventional UBE technique, it is challenging to perform ventral neuro decompression or discectomy at one side when there is bilateral recess stenosis or disc herniation. Although bilateral surgery can be performed, it'll significantly prolong the surgical time, increase breathing, and the risk of dural tears.For the case of lumbar spinal stenosis, combined with contralateral disc herniation, we established a third channel assist unilateral bipolar endoscopic technique to perform the controlled discectomy, which allows for the vertical entries into disc space and completely removes herniated disc fragments. The contralateral third channel is vertical to the lumbar spine in the TUBE technique. In this way, the surgical tools can access deep into the disc space and remove all fragments, thereby reducing recurrence rate, and avoiding dural injury.Compared to the traditional two channel UBE technique, the TUBE technique enables more efficient removal of the contralateral herniated disc and reduces risk of dural sac injury. Also, TUBE decreases soft tissue injury by avoiding two side UBE surgery.

Biportal Endoscopic Surgery for Lumbar Spinal Stenosis with Contralateral Disc Herniation

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.

Research

JoVE Journal

Medicine

Unilateral biportal endoscopic (UBE) spine surgery is an emerging minimally invasive surgical (MIS) technique that has gained popularity for treating ...