This work was supported by the Third Affiliated Hospital of Sun Yat-Sen University, Clinical Research Program (Grant Number: YHJH202203).

The Institutional Review Board of the Third Affiliated Hospital at Sun Yat-sen University approved the protocols (ID:[2022]02-356-01). All included patients were required to sign an informed consent form.
1. Surgical indications
<ol>
	<li>Include patients with lumbar spinal stenosis who have contra-lateral recess stenosis or disc herniation or who have contra-lateral neural compression.</li>
</ol>
2. Surgical method
<ol>
	<li>Perfor...

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

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brief+history,+global+trends,+and+Chinese+mission+of+unilateral+biportal+endoscopy+technique.">Brief history, global trends, and Chinese mission of unilateral biportal endoscopy technique.</a> Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 36 (10), 1181-1815 (2022).</li><li>Xie, X., Zhang, G., Liu, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+effect+of+unilateral+biportal+endoscopy+in+the+treatment+of+lumbar+diseases:+a+systematic+review+and+meta-analysis.">Clinical effect of unilateral biportal endoscopy in the treatment of lumbar diseases: a systematic review and meta-analysis.</a> Wideochir Inne Tech Maloinwazyjne. 17 (1), 61-68 (2022).</li><li>Wang, B., He, P., Liu, X., Wu, Z., Xu, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complications+of+unilateral+biportal+endoscopic+spinal+surgery+for+lumbar+spinal+stenosis:+A+systematic+review+of+the+literature+and+meta-analysis+of+single-arm+studies.">Complications of unilateral biportal endoscopic spinal surgery for lumbar spinal stenosis: A systematic review of the literature and meta-analysis of single-arm studies.</a> Orthop Surg. 15 (1), 3-15 (2023).</li><li>Kim, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biportal+endoscopic+spinal+surgery+for+lumbar+spinal+stenosis.">Biportal endoscopic spinal surgery for lumbar spinal stenosis.</a> Asian Spine J. 13 (2), 334-342 (2019).</li><li>Lin, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+systematic+review+of+unilateral+biportal+endoscopic+spinal+surgery:+Preliminary+clinical+results+and+complications.">A systematic review of unilateral biportal endoscopic spinal surgery: Preliminary clinical results and complications.</a> World Neurosurg. 125, 425-432 (2019).</li><li>Heo, D. D., Lee, D. C., Park, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+analysis+of+three+types+of+minimally+invasive+decompressive+surgery+for+lumbar+central+stenosis:+biportal+endoscopy,+uniportal+endoscopy,+and+microsurgery.">Comparative analysis of three types of minimally invasive decompressive surgery for lumbar central stenosis: biportal endoscopy, uniportal endoscopy, and microsurgery.</a> Neurosurg Focus. 46 (5), E9 (2019).</li><li>Kim, J., Park, C., Yeung, Y., Suen, T., Jun, S. G., Park, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unilateral+bi-portal+endoscopic+decompression+via+the+contralateral+approach+in+asymmetric+spinal+stenosis:+A+technical+note.">Unilateral bi-portal endoscopic decompression via the contralateral approach in asymmetric spinal stenosis: A technical note.</a> Asian Spine J. 15 (5), 688-700 (2021).</li><li>Hawker, G. A., Mian, S., Kendzerska, T., French, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measures+of+adult+pain:+Visual+Analog+Scale+for+Pain+(VAS+Pain),+Numeric+Rating+Scale+for+Pain+(NRS+Pain),+McGill+Pain+Questionnaire+(MPQ),+Short-Form+McGill+Pain+Questionnaire+(SF-MPQ),+Chronic+Pain+Grade+Scale+(CPGS),+Short+Form-36+Bodily+Pain+Scale+(SF-36+BPS),+and+Measure+of+Intermittent+and+Constant+Osteoarthritis+Pain+(ICOAP).">Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP).</a> Arthritis Care Res (Hoboken). 11, S240-S252 (2011).</li><li>Smeets, R., K&#246;ke, A., Lin, C., Ferreira, M., Demoulin, C. <a target="_blank" 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The UBE technique is an innovative endoscopic surgery that has rapidly advanced in recent years for the treatment of spinal disorders12. In contrast to PELD, UBE does not require specialized instruments and is similar to conventional surgical procedures. This may reduce costs and eliminate the need for extensive training, particularly for surgeons experienced in arthroscopic surgery13. Therefore, the UBE technique has been widely used for discectomy, spinal canal decompress...

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.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bone dissector</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-BLQ001</td>
			<td>Used for soft tissue expansion and laminar bone surface soft tissue stripping. Curved streamline design, better hand holding, one device and two uses, one end as soft tissue expansion, the other end as bone tissue dissection, fully expand and dissect the lamina and facet soft tissue.</td>
		</tr>
		<tr>
			<td>Electric surgical equipment for osseous tissue</td>
			<td>Viewall</td>
			<td>VP7110</td>
			<td>Used to grind off vertebral plate and partial facet bone; in the device channel, it is used for processing bone tissue; grind bone tissue at high speed, without damage to soft tissues such as nerve vessel; even grind close to nerve root, without damage to nerve; it is safer and faster.</td>
		</tr>
		<tr>
			<td>Expandable Channel</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-KZG001</td>
			<td>Perform channel dilation</td>
		</tr>
		<tr>
			<td>Handle of scalpel</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-DB001</td>
			<td>Used to Install scalpel</td>
		</tr>
		<tr>
			<td>Mouth gag</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-KKQ001</td>
			<td>Used to handle annulus breaks prior to disc</td>
		</tr>
		<tr>
			<td>Nerve hook</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-LG001</td>
			<td>Used for traction of nerve root in surgery; under endoscopic surgical field, pull apart and protect nerve root in instrument channel and can simultaneously enter other instruments for processing intervertebral disc.</td>
		</tr>
		<tr>
			<td>Nucleus pulposus forceps</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-SHQ003</td>
			<td>Used for clamping soft tissue and nucleus pulposus tissue of intervertebral disc during operation. Different angles and sizes allow easier grasping of soft tissue in various locations during surgery, and the finger loop design is ergonomic and easy to perform, along with gunshot forceps.</td>
		</tr>
		<tr>
			<td>Osteotome</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-GZ001</td>
			<td>During the operation, handle the lamina and facet, osteotomes with different angles and sizes can efficiently and flexibly chisel the facet and laminar bone</td>
		</tr>
		<tr>
			<td>Radiofrequency electrode</td>
			<td>GAOTONG</td>
			<td>DZX-T2430-A160</td>
			<td>Used for hemostasis ablation, cutting and cleaning soft tissue under endoscope during operation</td>
		</tr>
		<tr>
			<td>Rongeur</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-YGQ002</td>
			<td>During the operation, the laminar and facet bones were bitten and cut, the bone window was enlarged, and different sizes and angles were different. The bitewing mouth of the large incision easily bitewed off different bony tissues and calcified tissues, greatly saving the operation time, gun design, better hand holding sensation, and more forceful biting of bony tissues during the operation</td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-SSD001</td>
			<td>Used to cut the annulus fibrosus</td>
		</tr>
		<tr>
			<td>Tissue Liberator</td>
			<td>Hengsheng Medical Instrument Co., Ltd.</td>
			<td>PMT-BLQ002</td>
			<td>Used for stripping soft tissue in surgery, bidirectionally at different angles; used for stripping and separating mucosal tissue under instrument channel.</td>
		</tr>
	</tbody>
</table>

the third channel-assisted unilateral biportal endoscopic technique for lumbar spinal stenosis combined with contralateral disc herniation

Unilateral biportal endoscopic (UBE) spine surgery is an emerging minimally invasive surgical (MIS) technique that has gained popularity for treating lumbar spinal stenosis, particularly in Eastern Asia. The traditional UBE technique, with two portals on one side, can achieve successful unilateral laminotomy for bilateral decompression (ULBD) and, therefore, demonstrates favorable clinical outcomes. However, in the case of lumbar spinal stenosis combined with contralateral disc herniation, it is very difficult to remove the contralateral disc herniation, especially the loose disc fragment within the deep disc. Here, a third channel of the traditional UBE technique was developed to do the discectomy within the ipsilateral endoscopic vision, with which the instruments can go vertically into the contralateral disc, allowing easy discectomy. This technique can not only achieve adequate decompression of the bilateral spinal canal but also effectively remove contralateral herniated disc fragments. This technique avoids performing another UBE procedure on the opposite side, which can potentially shorten the duration of the operation, minimize blood loss and tissue damage, and ensure sufficient neural decompression. This paper will introduce the indications and surgical operation procedures, as well as present a classical case report and follow-up data, to facilitate the application of the third channel-assisted UBE (T-UBE) technique for spine surgeons.

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.

The T-UBE technique will be demonstrated in a typical case. A 65-year-old male complained of low back pain with bilateral numbness in his lower limbs for 10 months. The numbness is more pronounced on the right side and is accompanied by intermittent claudication, which occurs after walking 50 m. The symptoms on the left side were relieved by analgesic and neurotrophic drug treatment, but the symptoms on the right side persisted. Physical examination revealed mild tenderness of the spinous process and pain upon percussion...

Watch this Scientific Journal Video about The Third Channel-Assisted Unilateral Biportal Endoscopic Technique for Lumbar Spinal Stenosis Combined with Contralateral Disc Herniation at JoVE.com

Here, we present the third channel-assisted UBE technique, which allows for the vertical removal of herniated disc fragments. This technique can effectively address the limitations of traditional UBE techniques. This article will systematically elaborate on this procedure.

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