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>Perform bilateral endoscopic spinal canal decompression via UBE-ULBD technique and endoscopic discectomy via T-UBE.</li>
</ol>
3. Preoperative procedure
<ol>
	<li>Anesthesia and surgical position:
	<ol>
		<li>Under general anesthesia, position the patient prone on a spinal frame, avoiding any discomfort. Flex the lumbar spine slightly to open up the interlaminar space. 
		NOTE: General anesthesia with endotracheal intubation or combined spinal-epidural anesthesia is used for surgical procedures to minimize intraoperative pain.</li>
	</ol>
	</li>
	<li>Desired portals position (L4-5, for example):
	<ol>
		<li>Obtain a standard anteroposterior (AP) X-ray view, and let the target intervertebral space be vertical to the ground in the X-ray lateral view by adjusting the surgical table.</li>
		<li>Mark the bilateral pedicles of L5 and the ipsilateral pedicle of L4. Draw a line along the midline of the L4/5 intervertebral disc and the posterior midline of the spine.</li>
		<li>On the ipsilateral side, mark two incisions 1.5 cm above and below the midline of the intervertebral disc for manipulation and endoscopic portal, respectively. Locate the third channel incision on the contra-lateral midline of the L4/5 intervertebral disc space.</li>
	</ol>
	</li>
</ol>
4. Surgery procedure (L4-5, for example)
<ol>
	<li>Sterilize the surgical site with iodine tincture and 75% alcohol, and prepare the site with waterproof drapes.</li>
	<li>Establish UBE endoscopic channel and ipsilateral working channel.
	<ol>
		<li>Insert two syringe needles from the medial edge of the line of the ipsilateral pedicle shadow, one at 15 mm cranial and the other at 15 mm caudal, to the midline of the L4/5 intervertebral disc. The inserted needles will form a triangle and meet at the L4/5 interlaminar.</li>
		<li>Then, make two 8-10 mm longitudinal skin incisions for endoscopic and manipulated portals based on the location of the aforementioned needles.</li>
		<li>After dissecting the extralaminal soft tissue with a curette, insert serial dilators to expand the surgical field. Then, establish the endoscopic channel and working channel, converging along the sublaminar edge.</li>
	</ol>
	</li>
	<li>Establish endoscopic operating space (Figure 1A-C)
	<ol>
		<li>Insert a 30-degree endoscope via the viewing channel, connected to a continuous gravity saline irrigation positioned 50-60 cm high above the patient.</li>
		<li>After that, insert the surgical instruments and a radiofrequency ablation blade via the working channel to remove the soft tissue on the laminar surface until exposure of the lower edge of the L4 lamina, the ligamentum flavum, and the medial edge of the ipsilateral L4/5 facet joint. Establish the endoscopic operating space.</li>
	</ol>
	</li>
	<li>Ipsilateral laminotomy and neural decompression (Figure 2A-D, Figure 3A-D)
	<ol>
		<li>Remove the ipsilateral lower part of the L4 lamina, the upper part of the L5 lamina, and the medial inferior facet by a 3.5-mm high-speed drill (8000 rotations/s) and Kerrison punches until the ligamentum flavum is fully mobilized.</li>
		<li>Then, separate the ligamentum flavum from the dural sac and gradually remove it from the cranial to the caudal end with Kerrison punches or forceps.</li>
		<li>After that, carefully remove the medial facet joint of L4/5 and the hyperplastic facet joint bone with a soft-tissue protection drill or punches until the traversing nerve root is completely decompressed.</li>
		<li>Ensure that more than 50% of the medial facet is preserved, avoiding the possibility of spinal instability.</li>
	</ol>
	</li>
	<li>Contra-lateral dorsal neural decompression (Figure 4A-E)
	<ol>
		<li>Remove the base of the L4 spinous process with a drill (8000 rotations/s) and adjust the working channel obliquely towards the contralateral spinal canal.</li>
		<li>Undercut the medial part of the contralateral L4 inferior facet, fully expose the contralateral ligamentum, separate from the dural sac, and remove it using Kerrison punches (4 mm) until adequate dorsal neural decompression.</li>
	</ol>
	</li>
	<li>Contralateral third channel-assisted discectomy (Figure 5A-C, Figure 6A-E)
	<ol>
		<li>Make an 8-mm longitudinal skin incision adjacent (5 mm) to the spinous process at the midline of the contralateral disc. Insert a K-wire, followed by serial dilators under endoscopic view, to establish the contra-lateral working channel.</li>
		<li>After the thecal sac and contra-lateral traversing nerve root (L5) are retracted and well protected, expose the contralateral herniated disc fragment. Then, insert forceps or other instruments vertically into the contra-lateral disc space and remove the herniated disc tissues through the third channel.</li>
		<li>At last, use a blunt nerve hook to explore the dural sac and bilateral nerve roots to ensure sufficient spinal decompression.</li>
	</ol>
	</li>
	<li>Place a drainage tube outside the lamina and suture each incision to complete the operation. 
	NOTE: The surgical instruments used in the T-UBE technique are essentially the same as those used in the conventional UBE technique and traditional open spinal surgery. There is no need to purchase specialized instruments. T-UBE instruments include a 30-degree, 4-mm-diameter arthroscope, an endoscopic sheath, standard laminectomy instruments such as Kerrison punches, forceps, and nerve hooks, as well as a bipolar flexible radiofrequency probe, and a 3.5-mm radiofrequency electrode.</li>
</ol>

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

<ol>
	<li>Suvithayasiri, S., 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=The+role+and+clinical+outcomes+of+endoscopic+spine+surgery+of+treating+spinal+metastases;+Outcomes+of+29+cases+from+8+countries.">The role and clinical outcomes of endoscopic spine surgery of treating spinal metastases; Outcomes of 29 cases from 8 countries.</a> Neurospine. 20 (2), 608-619 (2023).</li><li>Choi, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+is+beautiful,+less+is+better.">Small is beautiful, less is better.</a> Neurospine. 16 (1), 3 (2019).</li><li>Yu, K. 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. 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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" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measures+of+function+in+low+back+pain/disorders:+Low+Back+Pain+Rating+Scale+(LBPRS),+Oswestry+Disability+Index+(ODI),+Progressive+Isoinertial+Lifting+Evaluation+(PILE),+Quebec+Back+Pain+Disability+Scale+(QBPDS),+and+Roland-Morris+Disability+Questionnaire+(RDQ).">Measures of function in low back pain/disorders: Low Back Pain Rating Scale (LBPRS), Oswestry Disability Index (ODI), Progressive Isoinertial Lifting Evaluation (PILE), Quebec Back Pain Disability Scale (QBPDS), and Roland-Morris Disability Questionnaire (RDQ).</a> Arthritis Care Res (Hoboken). 11, S158-S173 (2011).</li><li>Zhang, 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=Decompression+using+minimally+invasive+surgery+for+lumbar+spinal+stenosis+associated+with+degenerative+spondylolisthesis:+A+review.">Decompression using minimally invasive surgery for lumbar spinal stenosis associated with degenerative spondylolisthesis: A review.</a> Pain Ther. 10 (2), 941-959 (2021).</li><li>Chen, L., 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=The+learning+curve+of+unilateral+biportal+endoscopic+(UBE)+spinal+surgery+by+CUSUM+analysis.">The learning curve of unilateral biportal endoscopic (UBE) spinal surgery by CUSUM analysis.</a> Front Surg. 9, 873691 (2022).</li><li>Xu, H., Ni, J., Li, H., Fu, Y. <a target="_blank" 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The authors declare that they have no competing financial interests.

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.

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...

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

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.

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 ...

the-third-channel-assisted-unilateral-biportal-endoscopic-technique

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1.0K Views.  The Third Affiliated Hospital of Sun Yat-sen University. 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.

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

Acute and Chronic Tactile Sensory Testing after Spinal Cord Injury in Rats

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory testing in rat SCI models is needed. However, until recently, no single testing approach had been validated for SCI so that standardized methods have not been implemented across labs. Additionally, available testing methods could not be implemented acutely or when severe motor impairments existed, preventing studies of the development of SCI-induced allodynia3. Here we present two validated sensory testing methods using von Frey Hair (VFH) monofilaments which quantify changes in tactile sensory thresholds after SCI4-5. One test is the well-established Up-Down test which demonstrates high sensitivity and specificity across different SCI severities when tested chronically5. The other test is a newly-developed dorsal VFH test that can be applied acutely after SCI when allodynia develops, prior to motor recovery4-5. Each VFH monofilament applies a calibrated force when touched to the skin of the hind paw until it bends. In the up-down method, alternating VFHs of higher or lower forces are used on the plantar L5 dermatome to delineate flexor withdrawal thresholds. Successively higher forces are applied until withdrawal occurs then lower force VFHs are used until withdrawal ceases. The tactile threshold reflects the force required to elicit withdrawal in 50% of the stimuli. For the new test, each VFH is applied to the dorsal L5 dermatome of the paw while the rat is supported by the examiner. The VFH stimulation occurs in ascending order of force until at least 2 of 3 applications at a given force produces paw withdrawal. Tactile sensory threshold is the lowest force to elicit withdrawal 66% of the time. Acclimation, testing and scoring procedures are described. Aberrant trials that require a retest and typical trials are defined. Animal use was approved by Ohio State University Animal Care and Use Committee.

We describe two tactile sensory testing methods for acute or chronic periods of spinal cord injury in rats. These validated procedures can detect the development and maintenance of allodynia-like sensations.

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory ...

A Contusive Model of Unilateral Cervical Spinal Cord Injury Using the Infinite Horizon Impactor

While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of spinal cord injury (SCI) in which the thoracic spinal cord is injured. Additionally, because most human cord injuries occur as the result of blunt, non-penetrating trauma (e.g. motor vehicle accident, sporting injury) where the spinal cord is violently struck by displaced bone or soft tissues, the majority of SCI researchers are of the opinion that the most clinically relevant injury models are those in which the spinal cord is rapidly contused.1 Therefore, an important step in the preclinical evaluation of novel treatments on their way to human translation is an assessment of their efficacy in a model of contusion SCI within the cervical spinal cord. Here, we describe the technical aspects and resultant anatomical and behavioral outcomes of an unilateral contusive model of cervical SCI that employs the Infinite Horizon spinal cord injury impactor.
Sprague Dawley rats underwent a left-sided unilateral laminectomy at C5. To optimize the reproducibility of the biomechanical, functional, and histological outcomes of the injury model, we contused the spinal cords using an impact force of 150 kdyn, an impact trajectory of 22.5&deg; (animals rotated at 22.5&deg;), and an impact location off of midline of 1.4 mm. Functional recovery was assessed using the cylinder rearing test, horizontal ladder test, grooming test and modified Montoya's staircase test for up to 6 weeks, after which the spinal cords were evaluated histologically for white and grey matter sparing.
The injury model presented here imparts consistent and reproducible biomechanical forces to the spinal cord, an important feature of any experimental SCI model. This results in discrete histological damage to the lateral half of the spinal cord which is largely contained to the ipsilateral side of injury. The injury is well tolerated by the animals, but does result in functional deficits of the forelimb that are significant and sustained in the weeks following injury. The cervical unilateral injury model presented here may be a resource to researchers who wish to evaluate potentially promising therapies prior to human translation.

A reliable and repeatable way to produce a cervical unilateral spinal cord injury using the Infinite Horizon impactor is described. The method takes advantage of a custom designed frame and clamp to stabilize the spine. The standardized procedure and biomechanical injury parameters result in sufficient and sustained injuries.

While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of ...

Topical Airway Anesthesia for Awake-endoscopic Intubation Using the Spray-as-you-go Technique with High Oxygen Flow

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can jeopardize their spontaneous breathing, topical anesthesia of the airway is a popular technique. The spray-as-you-go technique represents one of the simplest opportunities to anesthetize the airway mucosa. The application of local anesthetic through the working channel of the flexible endoscope is a widespread practice for anesthetists as well as pulmonologists. There is neither need for additional devices nor special training as a pre-requisite to perform this technique. However, a known clinical problem is the coughing and gagging reflex that may occur when the liquid anesthetic strikes the airway mucosa and other sensitive structures like the vocal cords. This can be avoided by the use of oxygen applied through the working channel with the aim of fogging the local anesthetic into finer particles. Furthermore, the oxygen flow provides a higher oxygen supply and contributes to a better view, dispersing mucus secretions and blood away from the lens. Using an atomizer with a high oxygen flow of 10 L/min we maximized these benefits, caused less coughing and had more satisfied and therefore cooperative patients. Possible, but very rare complications of using oxygen flow including gastric insufflation, organ rupture or barotrauma did not arise. We attribute the complication-free use of high oxygen flow to the design of the set, which permits flow and pressure release.

The topical anesthetic lidocaine was atomized using a high oxygen flow through the working channel of a flexible intubating endoscope to achieve topical airway anesthesia for awake endotracheal intubation. We prefer this modified spray-as-you-go technique for endoscopic intubation to classical bolus application because of higher patient satisfaction and better compliance.

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can ...

Ovine Lumbar Intervertebral Disc Degeneration Model Utilizing a Lateral Retroperitoneal Drill Bit Injury

Intervertebral disc degeneration is a significant contributor to the development of back pain and the leading cause of disability worldwide. Numerous animal models of intervertebral disc degeneration have been developed. The ideal animal model should closely mimic the human intervertebral disc with regard to morphology, biomechanical properties and the absence of notochordal cells. The sheep lumbar intervertebral disc model fulfils these criteria. We present an ovine model of intervertebral disc degeneration utilizing a drill bit injury through a lateral retroperitoneal approach. The lateral approach significantly reduces the incision and potential morbidity associated with the traditional anterior approach to the ovine spine. Utilization of a drill-bit method of injury affords the ability to produce a consistent and reproducible injury, of precise dimensions, that initiates a consistent degree of intervertebral disc degeneration. The focal nature of the annular and nucleus pulposus defect more closely mimics the clinical condition of focal intervertebral disc herniation. Sheep recover rapidly following this procedure and are typically mobile and eating within the hour. Intervertebral disc degeneration ensues and sheep undergo necropsy and subsequent analysis at periods from eight weeks. We believe that the drill bit injury model of intervertebral disc degeneration offers advantages over more conventional annular injury models.

Intervertebral disc degeneration is a significant contributor to back pain and a leading cause of disability worldwide. Numerous animal models of intervertebral disc degeneration exist. We demonstrate an ovine model of intervertebral disc degeneration, utilizing a drill bit, which achieves a consistent disc injury and reproducible level of disc degeneration.

Intervertebral disc degeneration is a significant contributor to the development of back pain and the leading cause of disability worldwide. Numerous ...

A Mobile Outside-in Technique of Transforaminal Lumbar Endoscopy for Lumbar Disc Herniations

Percutaneous endoscopic transforaminal lumbar discectomy (PETLD) has now become a standard of care for the management of lumbar disc disease. There are two techniques for the introduction of a working cannula with respect to disc&#8212;outside-in and inside-out. The aim of this prospective study is to describe the technical aspects of a novel mobile outside-in method in dealing with different types of disc prolapse. A total of 184 consecutive patients with unilateral lower limb radiculopathy due to lumbar disc prolapse were operated on with the mobile outside-in technique of PETLD. Their clinical outcomes were evaluated based on the type of disc prolapse they had, a visual analog scale (VAS) leg pain score, the Oswestry Disability Index (ODI), and the Macnab criteria. The completeness of the decompression was documented with a postoperative magnetic resonance imaging. The mean age of the patients was 50 &#177; 16 years and the male/female ratio was 2:1. The mean follow-up was 19 &#177; 6 months. A total of 190 lumbar levels were operated on (L1&#8211;L2: n = 4, L2&#8211;L3: n = 17, L3&#8211;L4: n = 27, L4&#8211;5: n = 123, and L5&#8211;S1: n = 19). Divided into types, the patient distribution was central: n = 14, paracentral: n = 74, foraminal: n = 28, far lateral: n = 13, superior-migrated: n = 8, inferior migrated: n = 38, and high canal compromise: n = 9. The mean operative time was 35 &#177; 12 (25 - 56) min and the mean hospital stay was 1.2 &#177; 0.5 (1&#8211;3) days. The VAS score for leg pain improved from 7.5 &#177; 1 to 1.7 &#177; 0.9. The ODI improved from 70 &#177; 8.3 to 23 &#177; 5. According to the Macnab criteria, 75 patients (40.8%) had excellent results, 104 patients (56.5%) had good results, and 5 patients (2.7%) had fair results. Recurrence (including early and late) was seen in 15 out of the 190 levels that were operated on (7.89%). This article presents a novel outside-in approach that relies on a precise landing within the foramen in a mobile manner and does not solely depend upon the enlargement of the foramen. It is more versatile in application and useful in the management of all types of disc prolapse, even in severe canal compromise and high migration.

Here we present a protocol of a novel outside-in technique of transforaminal endoscopic discectomy for lumbar disc herniations. The technical aspects of the technique, the wide indications of use, and the results of the treatment in 184 patients are described in detail.

Percutaneous endoscopic transforaminal lumbar discectomy (PETLD) has now become a standard of care for the management of lumbar disc disease. There are ...

Targeting Gray Rami Communicantes in Selective Chemical Lumbar Sympathectomy

Chemical lumbar sympathectomy (CLS) is a commonly used, minimally invasive procedure for the treatment of conditions including ischemic diseases of the lower extremities, hyperhidrosis, etc. It is commonly practiced to position the puncture needle tip in front of the anterior fascia of the psoas major muscle and inject the inactivating agent around the sympathetic trunk, which is defined as conventional CLS. Although relatively rare, ureteropelvic damage is the most frequently reported complication of conventional CLS and can cause serious harm to patients. We found that injecting the inactivating agent behind the anterior fascia, which only targets gray rami communicantes, helped achieve therapeutic efficacy in&#160;vasodilation, sweat reduction, and pain relief comparable to conventional CLS, and serious complications were largely reduced. We define this procedure as selective CLS. Here, we present a protocol of selective CLS. The precise needle tract and accurate evaluation of the spreading of the contrast agent are critical to ensure that the drug is injected behind the anterior fascia of the psoas major muscle. The needle tip is at approximately one-third the dividing line of the vertebral body in the lateral view of a lumbar X-ray. The contrast is mainly confined around the needle tip and spreads outward and downward along the psoas muscle fibers. In this way, the anterior fascia provides a natural barrier for the ureteropelvic area, and the psoas major muscle provides a natural barrier for the lumbar nerve root. There are several highlights of this article, including 1) a detailed description of the selective CLS procedures, 2) an explanation of the anatomical basis for the implementation of selective CLS, and 3) an explanation of the differences between selective and conventional CLS.

We present a protocol for selective chemical lumbar sympathectomy (CLS), which inactivates only gray rami communicantes and not the sympathetic trunk. Selective CLS can help achieve therapeutic efficacy in vasodilation, sweat reduction, and pain relief that are comparable to conventional CLS, and serious complications, particularly ureteropelvic damages, can be reduced.

Chemical lumbar sympathectomy (CLS) is a commonly used, minimally invasive procedure for the treatment of conditions including ischemic diseases of the ...

Modified Posterior Vertebral Column Resection for Patients with Thoracolumbar Kyphotic Deformity

Old compression vertebrae fracture or congenital kyphoscoliosis with abnormal vertebral body development and other diseases that invade the spine may cause severe thoracolumbar kyphotic deformity, often accompanied by intractable low back pain or compression of the spinal cord, leading to severe neurological symptoms or even paralysis. If conservative treatment cannot relieve the symptoms or correct the deformities, surgical treatment is usually needed. For severe kyphotic deformity, reconstruction of the physiological curvature and rigid fixation determine the prognosis of the patients. Osteotomy and orthopedics are the standard procedure for deformities with severe compression of the front and middle column, but the trauma to the patients is high, with a long operation time and massive blood loss. To avoid these disadvantages, we have developed a modified technique to remove the diseased vertebra unilaterally. In this technique, we use a modified trephine to resect the vertebral columns like in the pedicle screw technique by adding a locking instrument that can restrict the trephine to lower the risk of osteotomy and shorten the surgery time and blood loss.

We describe a modified technique for resecting the posterior vertebral column unilaterally based on a modified trephine for patients with thoracolumbar kyphotic deformity.

Old compression vertebrae fracture or congenital kyphoscoliosis with abnormal vertebral body development and other diseases that invade the spine may ...

A Rabbit Aortic Valve Stenosis Model Induced by Direct Balloon Injury

Animal models are emerging as an important tool to understand the pathologic mechanisms underlying aortic valve stenosis (AVS) because of the lack of access to reliable sources of diseased human aortic valves. Among the various animal models, AVS rabbit models are one of the most commonly used in large animal studies. However, traditional AVS rabbit models require a long-term period of dietary supplementation and genetic manipulation to induce significant stenosis in the aortic valve, limiting their use in experimental studies. To address these limitations, a new AVS rabbit model is proposed, in which stenosis is induced by a direct balloon injury to the aortic valve. The present protocol describes a successful technique for inducing AVS in New Zealand white (NZW) rabbits, with step-by-step procedures for the preparation, the surgical procedure, and the post-operative care. This simple and reproducible model offers a promising approach for studying the initiation and progression of AVS and provides a valuable tool for investigating the underlying pathological mechanisms of the disease.

An appropriate animal model is needed to understand the pathologic mechanisms underlying aortic valve stenosis (AVS) and to evaluate the efficacy of therapeutic interventions. The present protocol describes a new procedure for developing the AVS rabbit model via a direct balloon injury in vivo.

Animal models are emerging as an important tool to understand the pathologic mechanisms underlying aortic valve stenosis (AVS) because of the lack of ...

Full-Endoscopic Isolation Zone Technique for the Treatment of Lumbar Disc Herniation

Lumbar disc herniation (LDH) is a type of serious sinus or sciatic nerve dysfunction caused by nucleus pulposus protrusion and annulus fibrosus tears. Its clinical symptoms often include severe low back pain, limited lumbar movement, sciatic nerve pain in the lower limbs, and even cauda equina syndrome. The common treatment for LDH is a conservative treatment scheme involving medicine, rest, and physical therapy. However, if the conservative treatment scheme is ineffective, a surgical treatment approach is adopted. Traditional open lumbar surgery has some disadvantages, including the potential for severe surgical trauma, severe blood loss during the operation, instability of the lumbar spine, and loss of the lumbar motor unit. Among the minimally invasive surgical schemes, full-endoscopic spine surgery (FESS) is undoubtedly the most appropriate and has the advantages of minimal trauma, high safety, quick postoperative recovery, and the retention of the stable structure and the motor unit of the lumbar spine. However, simultaneously, incomplete removal of the nucleus pulposus and residual nerve dysfunction after surgery can occur. To avoid these shortcomings, we studied a specific spinal endoscopy technique, the "isolation zone" surgical strategy, which can effectively block the pain from the nerve conduction pathway by completely relieving the nerve compression and nerve dysfunction through the orderly treatment of the protruding nucleus pulposus, the fissure of the annulus fibrosus, the sinus nerve, and the surrounding inflammatory soft tissues.

Here, we present a protocol for the &#34;isolation zone&#34; technique in the treatment of lumbar disc herniation (LDH) under full-endoscopic spine surgery (FESS), including intervertebral foramen formation, targeted catheterization, nucleus pulposus resection, and annulus fibrosus formation, which together completely block the pain from the nerve conduction pathway.

Lumbar disc herniation (LDH) is a type of serious sinus or sciatic nerve dysfunction caused by nucleus pulposus protrusion and annulus fibrosus tears. Its ...

Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for minimally invasive anterior lumbar interbody fusion (Mini-ALIF). This article is a technical description of anterior lumbar spine surgery under a microscope. We retrospectively collected information on patients who underwent microscope-assisted Mini-ALIF surgery at our hospital between July 2020 and August 2022. A repeated-measures ANOVA was used to compare imaging indicators between periods. Forty-two patients were included in the study. The mean volume of intraoperative bleeding was 180 mL, and the mean operative time was 143 min. The mean follow-up time was 18 months. Apart from one case of peritoneal rupture, no other serious complications occurred. The postoperative foramen and disc height were both higher on average than before surgery. The spreader-assisted micro-Mini-ALIF is simple and easy to use. It can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

The technique described in this article is well-suited to the Mini-ALIF procedure, allows for excellent exposure and decompression, and facilitates microscope-assisted manipulation.

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for ...