This study was conducted in strict accordance with the protocols established by the Institutional Review Boards of Zhongshan Hospital and Minhang Hospital, both affiliated with Fudan University (approval numbers: 2021-042 and 2021-037-01X, respectively). All participating patients provided informed written consent. Exclusion criteria were rigorously applied: patients with foraminal stenosis, multi-level stenosis, significant instability, a medical history of previous lumbar spine surgical interventions, or those presenting with degenerative spondylolisthesis of grade 2 or higher were considered ineligible for the study.
1. Patient preparation
<ol>
	<li>Perform the surgery under general anesthesia following approved protocols.</li>
	<li>Place the patient in a prone position on a radiopermeable operating table, and flex appropriately (Figure 2).</li>
	<li>Select the responsible lumbar segment causing clinical symptoms as the operative segment. 
	NOTE: For the convenience of description, the most common L4-5 stenosis was selected as an example to describe the surgical technique in this report. Other segments are similar to L4-5.</li>
	<li>Generally, select the more symptomatic side as the side of the surgical approach. In this report, the left side was selected as the surgical side for introduction.</li>
	<li>Determine the skin incision and working channel docking point on the anteroposterior view of fluoroscopy. Select the lateral edge of the left lumbar 4-5 interlaminar window as the docking target, and select its vertical projection on the body surface as the entry point of the skin.</li>
	<li>After the patient is routinely sterilized and draped, make a 10 mm stab wound in the skin deep to the fascia layer. Introduce a pencil-like rod with a 2 mm diameter to touch the bone (left L4-5 articular) under fluoroscopic guidance.</li>
</ol>
2. Insertion of endoscope
<ol>
	<li>Gradually expand the vertebral muscle and fascia using the soft tissue extender (see Table of Materials). Then, insert the 10 mm work sleeve with an oblique mouth. Verify the position of the working sleeve with fluoroscopy (Figure 3).</li>
	<li>Introduce the endoscopic surgical system (15&#176; viewing angle, outer diameter 10 mm, working channel diameter of 6 mm, and working length 125 mm), and perform all the subsequent steps under constant irrigation with endoscopic visualization.</li>
</ol>
3. Surgical procedure
<ol>
	<li>Under high-definition endoscopic visualization, dissect the soft tissue off the bone, and perform hemostasis using the radiofrequency probe (see Table of Materials). Confirm the presence of important anatomical structures, including the lower half of the left L4 lamina, left L4-5 facet joint, the upper 1/3 of the left L5 lamina, the base of the spinous process of L4 and L5, and the proliferative ligamentum flavum within the lumbar 4-5 interlaminar window1.</li>
	<li>Initiate ipsilateral bony decompression, starting from the L4 lamina. Remove the lower part of the L4 lamina, the medial part of the L4-5 articular process, and the upper edge of the L5 lamina using a 3.5 mm endoscopic diamond bur, trephine, and Kerrison Rongeur (see Table of Materials).
	<ol>
		<li>Utilize the 5 mm diameter endoscopic trephine (see Table of Materials) to effectively remove the L4 inferior articular process, which is surrounded by joint capsule and ligament. Separate and remove the superficial layer of the ligamentum flavum from the inner layer with a rongeur. 
		NOTE: Retain the inner layer of the ligamentum flavum in place, as it is tightly attached to the inner surface of the lamina and the medial border of the L5 superior articular process.</li>
		<li>The goal of lamina decompression in this step is to expose the cephalad and caudal free margins of the deep layer of the ligamentum flavum. Cut the medial border of the L5 superior articular process to free the lateral margin of the ligamentum flavum.</li>
	</ol>
	</li>
	<li>Proceed with contralateral bony decompression, starting from the base of the spinous process of L4. Shave the base of the spinous process to create sufficient space, facilitating the insertion of the working cannula (working channel diameter of 6 mm, and working length 125 mm) towards the contralateral side.
	<ol>
		<li>Polish the contralateral lower part of the L4 lamina from the inner surface to expose the cephalad free margin of the ligamentum flavum.</li>
		<li>Similarly, shave the base of the L5 spinous process and remove the upper edge of the L5 lamina to expose the caudal free margin of the ligamentum flavum. Detach the contralateral lateral margin of the ligamentum flavum from the contralateral L5 superior articular process.</li>
		<li>Remove the medial part of the L5 superior articular process using a diamond bur and/or Kerrison Rongeur.</li>
	</ol>
	</li>
	<li>After completing bony decompression and releasing ligamentum flavum attachments, remove the ligamentum flavum either in an en bloc manner or in a piecemeal manner.</li>
	<li>Remove the inner layer of the ligamentum flavum at the end of the operation. This step helps protect nerve elements during osteotomy and reduces vision blurring caused by epidural hemorrhage.</li>
	<li>Explore both lateral recesses to ensure thorough decompression of bilateral traversing nerves. If necessary, perform further decompression of the ligamentum flavum and its attached bony structures using endoscopic Kerrison Rongeur.</li>
	<li>Conclude the procedure when the dura and bilateral traversing nerve roots are free. Perform careful hemostasis using endoscopic radiofrequency bipolar. Close the skin incision with one or two stitches (approximately 1 cm).</li>
</ol>
4. Post-operative care and follow-up
<ol>
	<li>After lying down for 8 h post-surgery, ask the patients to walk, but ensure that they wear support around their waist.</li>
	<li>Provide proper guidance to the patients on exercises to aid in their recovery. Carefully monitor and address any swelling or pain that may occur after the operation.</li>
	<li>After 7 days of the surgery, encourage them to gradually resume their usual routines. Conduct regular check-ins to assess their healing progress.</li>
</ol>

Treating Lumbar Spinal Stenosis with a Minimally Invasive Spine Surgery

<ol>
	<li>Benini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumbar+spinal+stenosis.+An+overview+50+years+following+initial+description.">Lumbar spinal stenosis. An overview 50 years following initial description.</a> Der Orthopade. 22 (4), 257-266 (1993).</li><li>Cinotti, G., Postacchini, F., Fassari, F., Urso, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predisposing+factors+in+degenerative+spondylolisthesis:+a+radiographic+and+CT+study.">Predisposing factors in degenerative spondylolisthesis: a radiographic and CT study.</a> International Orthopaedics. 21, 337-342 (1997).</li><li>Torudom, Y., Dilokhuttakarn, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+portal+percutaneous+endoscopic+decompression+for+lumbar+spinal+stenosis:+preliminary+study.">Two portal percutaneous endoscopic decompression for lumbar spinal stenosis: preliminary study.</a> Asian Spine Journal. 10 (2), 335 (2016).</li><li>Atlas, S. J., Keller, R. B., Robson, D., Deyo, R. A., Singer, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+and+nonsurgical+management+of+lumbar+spinal+stenosis:+four-year+outcomes+from+the+maine+lumbar+spine+study.">Surgical and nonsurgical management of lumbar spinal stenosis: four-year outcomes from the maine lumbar spine study.</a> Spine. 25 (5), 556-562 (2000).</li><li>Atlas, S. J., Keller, R. B., Wu, Y. A., Deyo, R. A., Singer, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+outcomes+of+surgical+and+nonsurgical+management+of+lumbar+spinal+stenosis:+8+to+10+year+results+from+the+maine+lumbar+spine+study.">Long-term outcomes of surgical and nonsurgical management of lumbar spinal stenosis: 8 to 10 year results from the maine lumbar spine study.</a> Spine. 30 (8), 936-943 (2005).</li><li>Malmivaara, A., 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=Lumbar+spinal+research+group.+surgical+or+nonoperative+treatment+for+lumbar+spinal+stenosis?:+a+randomized+controlled+trial.">Lumbar spinal research group. surgical or nonoperative treatment for lumbar spinal stenosis?: a randomized controlled trial.</a> Spine. 32 (1), 1-8 (2007).</li><li>Parker, S. 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=Cost-effectiveness+of+multilevel+hemilaminectomy+for+lumbar+stenosis-associated+radiculopathy.">Cost-effectiveness of multilevel hemilaminectomy for lumbar stenosis-associated radiculopathy.</a> The Spine Journal. 11 (8), 705-711 (2011).</li><li>Parker, S. 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=Two-year+comprehensive+medical+management+of+degenerative+lumbar+spine+disease+(lumbar+spondylolisthesis,+stenosis,+or+disc+herniation):+a+value+analysis+of+cost,+pain,+disability,+and+quality+of+life.">Two-year comprehensive medical management of degenerative lumbar spine disease (lumbar spondylolisthesis, stenosis, or disc herniation): a value analysis of cost, pain, disability, and quality of life.</a> Journal of Neurosurgery: Spine. 21 (2), 143-149 (2014).</li><li>Fox, M. W., Onofrio, B. M., Hanssen, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+outcomes+and+radiological+instability+following+decompressive+lumbar+laminectomy+for+degenerative+spinal+stenosis:+a+comparison+of+patients+undergoing+concomitant+arthrodesis+versus+decompression+alone.">Clinical outcomes and radiological instability following decompressive lumbar laminectomy for degenerative spinal stenosis: a comparison of patients undergoing concomitant arthrodesis versus decompression alone.</a> Journal of Neurosurgery. 85 (5), 793-802 (1996).</li><li>J&#246;nsson, B., Annertz, M., Sj&#246;berg, C., Str&#246;mqvist, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+prospective+and+consecutive+study+of+surgically+treated+lumbar+spinal+stenosis:+part+II:+five-year+follow-up+by+an+independent+observer.">A prospective and consecutive study of surgically treated lumbar spinal stenosis: part II: five-year follow-up by an independent observer.</a> Spine. 22 (24), 2938-2944 (1997).</li><li>Ghogawala, Z., 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=Laminectomy+plus+fusion+versus+laminectomy+alone+for+lumbar+spondylolisthesis.">Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis.</a> New England Journal of Medicine. 374 (15), 1424-1434 (2016).</li><li>Komp, M., 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=Bilateral+spinal+decompression+of+lumbar+central+stenosis+with+the+full-endoscopic+interlaminar+versus+microsurgical+laminotomy+technique:+a+prospective,+randomized,+controlled+study.">Bilateral spinal decompression of lumbar central stenosis with the full-endoscopic interlaminar versus microsurgical laminotomy technique: a prospective, randomized, controlled study.</a> Pain Physician. 18 (1), 61 (2015).</li><li>Ito, F., 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=Step-by-step+sublaminar+approach+with+a+newly-designed+spinal+endoscope+for+unilateral-approach+bilateral+decompression+in+spinal+stenosis.">Step-by-step sublaminar approach with a newly-designed spinal endoscope for unilateral-approach bilateral decompression in spinal stenosis.</a> Neurospine. 16 (1), 41 (2019).</li><li>Lee, C. W., Yoon, K. J., Jun, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Percutaneous+endoscopic+laminotomy+with+flavectomy+by+uniportal,+unilateral+approach+for+the+lumbar+canal+or+lateral+recess+stenosis.">Percutaneous endoscopic laminotomy with flavectomy by uniportal, unilateral approach for the lumbar canal or lateral recess stenosis.</a> World Neurosurgery. 113, e129-e137 (2018).</li><li>McGrath, L. B., White-Dzuro, G. A., Hofstetter, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+clinical+outcomes+following+minimally+invasive+or+lumbar+endoscopic+unilateral+laminotomy+for+bilateral+decompression.">Comparison of clinical outcomes following minimally invasive or lumbar endoscopic unilateral laminotomy for bilateral decompression.</a> Journal of Neurosurgery: Spine. 30 (4), 491-499 (2019).</li><li>Pairuchvej, S., Muljadi, J. A., Ho, J. C., Arirachakaran, A., Kongtharvonskul, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full-endoscopic+(bi-portal+or+uni-portal)+versus+microscopic+lumbar+decompression+laminectomy+in+patients+with+spinal+stenosis:+systematic+review+and+meta-analysis.">Full-endoscopic (bi-portal or uni-portal) versus microscopic lumbar decompression laminectomy in patients with spinal stenosis: systematic review and meta-analysis.</a> European Journal of Orthopaedic Surgery &amp; Traumatology. 30, 595-611 (2020).</li><li>Kim, H. S., Wu, P. H., Jang, I. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumbar+endoscopic+unilateral+laminotomy+for+bilateral+decompression+outside-in+approach:+a+proctorship+guideline+with+12+steps+of+effectiveness+and+safety.">Lumbar endoscopic unilateral laminotomy for bilateral decompression outside-in approach: a proctorship guideline with 12 steps of effectiveness and safety.</a> Neurospine. 17 (Suppl 1), S99 (2020).</li></ol>

The authors have nothing to disclose.

With the progressive evolution of percutaneous endoscopic spine surgery and clinicians&#39; profound comprehension of endoscopic procedures, the therapeutic indications for endoscopic lumbar interventions have expanded to encompass all manifestations of LSS, branching out from merely addressing lumbar disc herniation. The spectrum of endoscopic management for LSS includes stenosis decompression, contralateral decompression, and fusion facilitated by endoscopic visualization. An increasing volume of research underscores that LE-ULBD yields outcomes analogous to those obtained via micro-lumbar decompression laminectomy. The LE-ULBD technique is endowed with several merits, including high-definition intraoperative visualization, minimized soft tissue trauma, and an expedited post-operative recovery trajectory12,13,14,15,16,17.
LE-ULBD is optimally tailored for addressing central canal stenosis, lateral recess stenosis, or an amalgamation of both presentations. For those presenting with grade 1 spondylolisthesis1, LE-ULBD can be judiciously considered as a surgical intervention. For cases indicative of intervertebral foramen stenosis, transforaminal endoscopic decompression is typically the method of choice.
The procedure consists of the following key steps. First, bone decompression must be performed before the complete removal of the ligamentum flavum. Drilling above the ligamentum flavum can protect it from inadvertent durotomy. Second, the endpoint of lamina decompression is the cephalad and caudal aspects of the ligamentum flavum being exposed. Third, the endpoint for cutting the superior articular process is the lateral margin of the ligamentum flavum being exposed. In this step, the resection of the articular process should not exceed 1/2 because this may cause lumbar instability. Fourth, exploring the medial edge of the pedicle with a Kerrison rongeur is an important indicator of the decompression of the traversing nerve root. Of course, the best endpoint for nerve decompression is the lateral margin of the nerve root from the emitting site to the intervertebral foramen presented on the screen. Fifth, to obtain enough space to insert the working sleeve into the opposite side, we ground the base of the spinous process. Lastly, the endpoint is reached when the dura and bilateral traversing nerve roots are free.
Within our cohort, dural tears were observed in four patients, although none exhibited related symptoms. Upon detecting a dural tear, we promptly used a gelatin sponge to seal the compromised region of the dural sac and aimed to conclude the surgical intervention within the next 30 min. No post-operative infections occurred. Over time, Visual Analog Scale (VAS) scores for the 132 patients consistently declined, while Japanese Orthopedic Association (JOA) scores showed an ascending trend, and the Oswestry Disability Index (ODI) likewise decreased. At the 24-month post-operative point, the therapeutic efficacy, assessed using the modified MacNab criterion, was rated as &#34;excellent&#34; for 119 patients and &#34;good&#34; for the remaining13.
However, we must acknowledge the inherent limitations of our study: (1) This investigation was retrospective and limited by a small sample size. (2) Since the focus was exclusively on patients with single-level stenosis, the outcomes may not apply to cases involving multi-level stenosis. (3) Implementing this specific surgical technique requires meticulous preoperative planning and a deep familiarity with LE-ULBD operations.
The field of endoscopic spinal surgery is expanding, moving beyond its initial focus on lumbar disc degeneration to encompass a wider range of spinal pathologies, from the craniovertebral junction to the sacral vertebrae. Looking ahead, we anticipate the integration of cutting-edge technologies, such as robotics and artificial intelligence-enhanced navigation, which are poised to bring transformative innovations to the realm of endoscopic spine surgery.

Degenerative lumbar spinal stenosis (DLSS) can result from alterations in bony, discal, capsular, or ligamentary anatomical structures. Clinically, LSS presents with a range of symptoms, including radiating sciatic pain in the legs, neurogenic claudication during ambulation, and sensory disturbances, all of which significantly affect patients&#39; quality of life1,2,3. An initial conservative management period of two months is the recommended therapeutic approach for LSS. If conservative measures prove ineffective, transitioning to surgical decompression therapy becomes the subsequent recommendation.
Historically, open laminectomy has been the traditional surgical approach for addressing spinal stenosis. Peer-reviewed studies have confirmed its safety and cost-effectiveness, with outcomes showing notable superiority compared to non-surgical interventions4,5,6,7,8. However, the complexities involved in achieving comprehensive bony decompression of neural components can introduce the risk of segmental spinal instability. This may lead to symptom recurrence or a subsequent need for arthrodesis9,10. Distinctively, Ghogawala et al.11 documented that approximately 34% of patients, after undergoing traditional laminectomy for lumbar spinal stenosis with concomitant stable spinal spondylolisthesis, required revision surgery within four years post-operatively.
Over the past five decades, a discernible shift toward minimally invasive spinal surgical procedures has become evident. The overarching objective has been to reduce approach-related tissue disruption and subsequently mitigate post-operative discomfort and disability. This transition aligns seamlessly with the advent and progression of percutaneous endoscopic spine surgery.
Synchronized with advancements in endoscopic technology and a deepened understanding of endoscopic anatomical intricacies, contemporary endoscopic spine surgeons are now equipped to address a spectrum of LSS presentations safely and effectively. Specifically, lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) has gained traction as a favored modality for LSS management12,13,14,15,16,17(Figure 1). Paramount benefits of LE-ULBD include minimal incision requirements, avoidance of soft tissue disruption and muscular denervation, along with improved visualization.
Between May 2017 and May 2021, our institution employed the LE-ULBD technique to manage 132 patients with LSS. Relevant technical details and outcomes over a two-year follow-up period are elucidated herein. Based on these findings, LE-ULBD emerges as a minimally invasive, effective, and secure modality, positioning it as a viable alternative therapeutic strategy for patients diagnosed with lumbar central canal stenosis and/or lateral recess stenosis.

<table><tbody><tr><td>Kerrison Rongeur&amp;nbsp;</td><td>Joimax GmbH, Karlsruhe, Germany</td><td></td><td></td></tr><tr><td>The endoscopic high-speed&amp;nbsp;diamond burr</td><td>NSK-Nakanishi International, Co., Ltd., Osaka, Japan</td><td>Primado P200-RA330</td><td></td></tr><tr><td>The endoscopic surgical system Delta</td><td>Joimax GmbH, Karlsruhe, Germany</td><td></td><td></td></tr><tr><td>The radiofrequency probe</td><td>Elliquence LLC, Baldwin, New York</td><td>Trigger-FlexR Bipolar System</td><td></td></tr><tr><td>Trephine</td><td>Joimax GmbH, Karlsruhe, Germany</td><td></td><td></td></tr></tbody></table>

percutaneous endoscopic unilateral-approach bilateral decompression for lumbar spinal stenosis

Lumbar spinal stenosis (LSS) involves the narrowing of the spinal canal due to degenerative changes in the vertebral joints, intervertebral discs, and ligaments. LSS encompasses central canal stenosis (CCS), lateral recess stenosis (LRS), and intervertebral foramen stenosis (IFS). The utilization of lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) has gained popularity in the treatment of CCS and LRS. This popularity is attributed to the rapid development of endoscopic instruments and the progress of endoscopic philosophy.
In this technical report, a detailed introduction to the steps and key points of LE-ULBD is provided. Simultaneously, a retrospective review of 132 consecutive patients who underwent LE-ULBD for central canal and/or lateral recess stenosis was conducted. The outcomes after more than two years of follow-up were assessed using the visual analogue score (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) scores, and the modified MacNab criteria to evaluate surgical efficacy. All 132 patients underwent LE-ULBD successfully. Among them, 119 patients were rated as "excellent," while 13 patients were rated as "good" based on the modified MacNab criteria during the last follow-up. Incidental dural tears occurred in four cases, but there were no post-operative epidural hematomas or infections. The experience demonstrates that LE-ULBD is a less invasive, effective, and safe approach. It can be considered as an alternative option for treating patients with lumbar central canal stenosis and/or lateral recess stenosis.

Outcome evaluation
Surgical results were assessed using the Visual Analog Scale (VAS) scores for leg and back pain, Japanese Orthopaedic Association (JOA) Scores, Oswestry Disability Index (ODI) scores, and the modified MacNab standard12,15,17. These indicators were measured pre-operatively and at two days, six months, 12 months, and 24 months post-surgery.
Clinical outcome
All 132 patients who underwent surgery successfully completed the 24-month follow-up. There is a statistically significant difference in scores before and after the operation (P &#60; 0.001). According to the modified MacNab criteria17, all 132 patients exhibited satisfactory results at the final follow-up. Figure 4 and Figure 5 illustrate a clinical example of LE-ULBD performed. Changes in VAS scores, JOA scores, and ODI scores over time are presented in Table 1 and Figure 6. Figure 7 shows the clinical results based on the modified MacNab criteria.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65456/65456fig1.jpg" /> 
Figure 1: Overview of the protocol. Illustration depicting percutaneous endoscopic unilateral-approach bilateral decompression for lumbar spinal stenosis. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/65456/65456fig2.jpg" /> 
Figure 2: Patient positioning. The patient is positioned in a prone posture on a radiolucent operating table and appropriately flexed. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/65456/65456fig3.jpg" /> 
Figure 3: Confirming the correct placement of the working cannula through fluoroscopy. (A) Lateral view and (B) anteroposterior view. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/65456/65456fig4.jpg" /> 
Figure 4: LE-ULBD procedure. (A) Identification of the anatomical structures of the left L4 lamina, L5 lamina, and ligamentum flavum using (B) a diamond bur and (C) an endoscopic Kerrison Rongeur to enlarge the interlaminar window. (D,E) Identification of the cranial and caudal ends of the ligamentum flavum. (F) Decompression of the dural sac and bilateral traversing nerve roots. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/65456/65456fig5.jpg" /> 
Figure 5: Pre- and post-operative MRI and CT scans of a representative patient. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/65456/65456fig6.jpg" /> 
Figure 6: Changes in VAS, JOA, and ODI scores over time. Significant improvements in leg and back VAS scores (A,C), JOA scores (B), and ODI (D) during the follow-up period. The x-axes depict time, and the y-axes depict the scores. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/65456/65456fig7.jpg" /> 
Figure 7: Clinical results assessed according to the modified MacNab criteria. The x-axes depict time, and the y-axes depict the scores. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65456/65456fig7large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td rowspan="2">Time</td>
			<td rowspan="2">VAS leg pain scores</td>
			<td rowspan="2">VAS back pain scores</td>
			<td>JOA&#160;</td>
			<td>ODI</td>
		</tr>
		<tr>
			<td>scores</td>
			<td>(%)</td>
		</tr>
		<tr>
			<td>Pre-operative</td>
			<td>6.41 &#177; 1.33</td>
			<td>6.68 &#177; 1.43</td>
			<td>12.44 &#177; 1.87</td>
			<td>62.94 &#177; 9.52</td>
		</tr>
		<tr>
			<td>post-operative</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2 d</td>
			<td>2.06 &#177; 1.12</td>
			<td>1.89 &#177; 0.83</td>
			<td>16.69 &#177; 1.60</td>
			<td>26.56 &#177; 6.93</td>
		</tr>
		<tr>
			<td>6 m</td>
			<td>1.88 &#177; 1.16</td>
			<td>1.58 &#177; 0.88</td>
			<td>16.81 &#177; 1.85</td>
			<td>25.89 &#177; 6.74</td>
		</tr>
		<tr>
			<td>12 m</td>
			<td>1.78 &#177; 0.90</td>
			<td>1.26 &#177; 0.90</td>
			<td>17.62 &#177; 2.91</td>
			<td>25.44 &#177; 7.29</td>
		</tr>
		<tr>
			<td>24 m</td>
			<td>1.70 &#177; 1.10</td>
			<td>1.17 &#177; 1.02</td>
			<td>18.53 &#177; 2.80</td>
			<td>23.55 &#177; 7.46</td>
		</tr>
		<tr>
			<td>F value</td>
			<td>789.446</td>
			<td>1130.254</td>
			<td>287.64</td>
			<td>2243.436</td>
		</tr>
		<tr>
			<td>P value</td>
			<td>P &#60; 0.001</td>
			<td>P &#60; 0.001</td>
			<td>P &#60; 0.001</td>
			<td>P &#60; 0.001</td>
		</tr>
		<tr>
			<td>data as (x&#772;&#772;&#160;&#177; s)</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 1: Pre- and post-operative scores for 132 patients.

Read this Scientific Article Protocol about Percutaneous Endoscopic Unilateral-Approach Bilateral Decompression for Lumbar Spinal Stenosis at JoVE.com

Author Spotlight: Scope of LE-ULBD as a Safe, Effective, and Minimally Invasive Approach to Treat Lumbar Spinal Stenosis

The present protocol describes the steps and key points of lumbar endoscopic unilateral laminotomy for bilateral decompression for the treatment of degenerative lumbar spinal stenosis.

Percutaneous Endoscopic Unilateral-Approach Bilateral Decompression for Lumbar Spinal Stenosis

Lumbar spinal stenosis (LSS) involves the narrowing of the spinal canal due to degenerative changes in the vertebral joints, intervertebral discs, and ...

percutaneous-endoscopic-unilateral-approach-bilateral-decompression

Universidad San Sebastian

Research

JoVE Journal

Medicine

495 Views.  Minhang Hospital, Fudan University. The present protocol describes the steps and key points of lumbar endoscopic unilateral laminotomy for bilateral decompression for the treatment of degenerative lumbar spinal stenosis.

Video: Author Spotlight: Scope of LE-ULBD as a Safe, Effective, and Minimally Invasive Approach to Treat Lumbar Spinal Stenosis

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 ...

Controlled Cortical Impact Model for Traumatic Brain Injury

Every year over a million Americans suffer a traumatic brain injury (TBI). Combined with the incidence of TBIs worldwide, the physical, emotional, social, and economical effects are staggering. Therefore, further research into the effects of TBI and effective treatments is necessary. The controlled cortical impact (CCI) model induces traumatic brain injuries ranging from mild to severe. This method uses a rigid impactor to deliver mechanical energy to an intact dura exposed following a craniectomy. Impact is made under precise parameters at a set velocity to achieve a pre-determined deformation depth. Although other TBI models, such as weight drop and fluid percussion, exist, CCI is more accurate, easier to control, and most importantly, produces traumatic brain injuries similar to those seen in humans. However, no TBI model is currently able to reproduce pathological changes identical to those seen in human patients. The CCI model allows investigation into the short-term and long-term effects of TBI, such as neuronal death, memory deficits, and cerebral edema, as well as potential therapeutic treatments for TBI.

Traumatic brain injuries (TBIs) remain a serious health problem. Using the controlled cortical impact surgery model, research on the effects of TBI and possible treatment methods may be performed.

Every year over a million Americans suffer a traumatic brain injury (TBI).  Combined with the incidence of TBIs worldwide, the physical, emotional, ...

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 ...

Novel Percutaneous Approach for Deployment of 3D Printed Coronary Stenosis Implants in Swine Models of Ischemic Heart Disease

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally (3D) printed coronary implants can be employed to percutaneously create a focal coronary stenosis. However, reliable delivery of the implants can be difficult without the use of ancillary equipment. We describe the use of a mother-and-child coronary guide catheter for stabilization of the implant and for effective delivery of the 3D printed implant to any desired location along the length of the coronary vessel. The focal coronary narrowing was confirmed under coronary cineangiography and the functional significance of the coronary stenosis was assessed using gadolinium-enhanced first-pass cardiac perfusion MRI. We showed that reliable delivery of 3D printed coronary implants in swine models (n = 11) of ischemic heart disease can be achieved through repurposing mother-and-child coronary guide catheters. Our technique simplifies the percutaneous delivery of coronary implants to create closed-chest swine models of focal coronary artery stenosis and can be performed expeditiously, with a low procedural failure rate.

We describe a novel, cost-effective, and efficient technique for percutaneous delivery of three-dimensionally printed coronary implants to create closed-chest swine models of ischemic heart disease. The implants were fixed in place using a mother-and-child extension catheter with high success rate.

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally ...

A Two-Step Method for Percutaneous Transhepatic Choledochoscopic Lithotomy

Intrahepatic and extrahepatic choledocholithiasis is a challenge in the field of biliary surgery. We present our experience using a two-step percutaneous transhepatic choledochoscopic lithotomy (PTCSL) procedure to treat challenging biliary stones. We retrospectively reviewed 81 patients with intrahepatic and extrahepatic choledocholithiasis treated using this two-step PTCSL from January 2013 to January 2020, including 40 males and 41 females, with an average age of 66 years. In contrast to traditional percutaneous transhepatic cholangioscopy (PTCS), a channel was established directly through a 16F Amplatz sheath, and the stone in the channel was removed with the aid of a nephroscope. The clinical efficacy and complications of all patients were analyzed. Eighty-one patients (81/81, 100%) had their biliary stones successfully removed; 62/81 patients (76.5%) had biliary stones completely removed after the first operation; 17/81 patients (21%) underwent a second operation; 2/81 patients (2.5%) needed a third operation to completely remove the stones. The incidence of severe bleeding during the operation was 0%, and there were no deaths. The use of the two-step PTCSL method is safe and efficacious, and contributes to a better prognosis of intrahepatic and extrahepatic choledocholithiasis.

This "two-step method" significantly improved the success rate of percutaneous transhepatic choledochoscopy and achieved a better prognosis of intrahepatic and extrahepatic choledocholithiasis.

Intrahepatic and extrahepatic choledocholithiasis is a challenge in the field of biliary surgery. We present our experience using a two-step percutaneous ...

Full-Endoscopic Interlaminar Approach for Decompression of Lateral Recess Stenosis

For lateral recess stenosis, extensive decompression with laminectomy is still performed in most centers. However, tissue-sparing surgeries are becoming more common. Full-endoscopic spinal surgeries have the advantages of being less invasive and offering a shorter recovery time. Here, we describe the technique of the full-endoscopic interlaminar approach for the decompression of lateral recess stenosis. The full-endoscopic interlaminar approach for the lateral recess stenosis procedure took approximately 51 min (range of 39-66 min). Blood loss could not be measured due to continuous irrigation. However, no drainage was required. There were no dura mater injuries reported in our institution. Furthermore, there were no injuries to the nerves, no cauda equine syndrome, and no hematoma formation. The patients were mobilized on the same day as surgery and discharged the next day. Therefore, the full-endoscopic technique for lateral recess stenosis decompression is a feasible procedure that lowers the operational time, complications, traumatization, and rehabilitation duration.

Technical advances and increased experience in full-endoscopic spinal surgeries enable these procedures to be performed with minimal incision, muscle retraction, and bone removal.

For lateral recess stenosis, extensive decompression with laminectomy is still performed in most centers. However, tissue-sparing surgeries are becoming ...

Fully Endoscopic Mitral Valve Repair with Percutaneous Cannulation of Groin Vessels

Endoscopic mitral valve surgery (EMS) has become a standard of care at specialized heart centers, further reducing surgical trauma compared to a traditional minimally invasive, thoracotomy-based approach. Exposure of the groin vessels for the establishment of cardiopulmonary bypass (CPB) via surgical cutdown in minimally invasive surgery (MIS) may result in wound healing disorders or seroma formation. The avoidance of surgical exposure of the groin vessels by using fully percutaneous techniques for the insertion of a CPB cannula with the implementation of vascular pre-closure devices has the potential to reduce these complications and improve clinical results. Herein, we present the utilization of a novel plug based vacsular closure device with a resobable collagen plug and the absence of suture material for closure of the arterial access for CPB in MIS. While this device was initially predominantly used in transcatheter aortic valve implantation (TAVI) procedures, with its safety and feasibility shown, we herein show that it can be used in CPB cannulation, since it is capable of closing arterial access sites up to 25 French (Fr.) in size. This device may be suitable to significantly reduce groin complications in MIS and simplify the establishment of CPB. Here, we describe the fundamental steps of EMS, including percutaneous groin cannulation and decannulation using a vascular closure device.

This protocol demonstrates in detail how to perform fully endoscopic mitral valve surgery (EMS) with percutaneous cannulation of the groin vessels, using a percutaneous plug-based vascular closure device. Fundamental steps and useful instructions are described in detail for each step.

Endoscopic mitral valve surgery (EMS) has become a standard of care at specialized heart centers, further reducing surgical trauma compared to a ...

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 ...

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

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

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 ...

Unilateral Biportal Endoscopy for the Treatment of Lumbar Disc Herniation

Unilateral biportal endoscopy (UBE) is a minimally invasive spinal surgery technique increasingly employed in treating degenerative lumbar diseases, such as lumbar disc herniation, lumbar spinal stenosis, and spondylolisthesis. In UBE, two independent yet interconnected surgical channels are established-one for the endoscope and the other for surgical instruments-providing a broad and clear surgical field of view. UBE offers several advantages over traditional open surgery, including reduced tissue damage, shorter hospital stays, and faster recovery times. Additionally, it combines the benefits of microscopic surgery and interlaminar endoscopy, enhancing flexibility, accuracy, and reliability during the procedure. The learning curve for UBE is shorter than that for transforaminal endoscopy, as the surgical processes closely resemble those of conventional open surgery. Despite its favorable clinical outcomes, such as reduced blood loss and shorter hospitalization, UBE carries potential complications, including epidural hematoma, dural injury, and compression of the outlet nerve root. To mitigate these risks, it is crucial to ensure appropriate patient selection, apply the correct surgical technique, and engage in careful postoperative monitoring. This article provides a detailed summary of the step-by-step surgical techniques used in UBE for treating lumbar disc herniation. It serves as a comprehensive guide to enhance practitioners' understanding of UBE. The presentation also underscores the importance of rigorous training and expertise to ensure optimal patient outcomes.

Presented here is a step-by-step surgical protocol of unilateral biportal endoscopy (UBE), a minimally invasive approach for treating lumbar disc herniation. By using two ports, surgical accuracy and flexibility are enhanced. This article provides a comprehensive description of UBE and highlights the practical application of this approach in clinical practice.

Unilateral biportal endoscopy (UBE) is a minimally invasive spinal surgery technique increasingly employed in treating degenerative lumbar diseases, such ...