We would like to acknowledge scientific team members Jae Eun Park and Kyeong-rae Kim for providing their assistance in acquiring full-text articles and managing the digital works.

The protocol follows the guidelines of Nanoori Hospital&#39;s human research ethics committee. A written informed consent was obtained from all the patients with unilateral lower limb radiculopathy due to lumbar disc prolapse. The exclusion criteria were the presence of segmental instability, spondylolisthesis (more than grade 1), and the presence of significant spinal stenosis.
1. Patient Position and Skin Marking
<ol>
	<li>Place the patient in the prone position on the radiolucent operating table with the spine in slight flexion. 
	NOTE: Indications for surgery in patients are as follows: intractable, frequently unilateral radiculopathy resistant to conservative measures (for at least 6&#8211;8 weeks), with or without associated axial back pain, a positive tension sign on physical examination, and radiculopathy correlating with radiographic evidence on confirmatory MRI studies.</li>
	<li>Mark the midline of the spine, as well as the extent of the iliac crest, with a marking pen under an image intensifier.</li>
	<li>Mark the paraspinal skin entry point along the center of the disc space using the manual back assessment method6: check the borderline between the back muscles and the abdominal muscles. Mark the skin entry points just medial to this borderline in mid-disc level both in Antero-Posterior (AP) and lateral X-rays.</li>
</ol>
2. Local Anesthesia and Incision
<ol>
	<li>Infiltrate subcutaneous local anesthetic (2 mL of 1% lidocaine) around the entry point and then perform the skin incision of about 1 cm and infiltrate the trajectory with the local anesthetic (3 mL of 1% lidocaine) through a 23 G needle.</li>
	<li>Insert an 18 G spinal needle through the skin incision at a 25&#8211;35&#176; angle to horizontal.</li>
	<li>Pass the needle under the image intensifier through the fascia and the back muscles. Then, dock the needle at Kambin&#39;s triangle near the intervertebral disc. 
	NOTE: Kambin&#39;s triangle is present at the posterolateral aspect of the disc. The hypotenuse is the exiting nerve root, the base is the superior border of the inferior vertebra, and the height is the thecal sac/traversing nerve root.</li>
	<li>Check the free epidural space in Kambin&#39;s triangle by injecting 1.5 mL of contrast dye under the image intensifier. Provide local anesthesia in Kambin&#39;s triangle by injecting 8&#8211;10 mL of 1% lidocaine in the foraminal space followed by a booster injection of 2&#8211;4 mL of 1.6% lidocaine (8 mL of 2% lidocaine with 2 mL of saline plus 0.05 mL of epinephrine) 4&#8211;5 min after the initial injection.</li>
</ol>
3. Discography
<ol>
	<li>Insert the needle in the discal space under fluoroscopy and perform discography by injecting 2 mL of 0.8% indigo carmine mixed with contrast.</li>
</ol>
4. Insertion of Endoscope
<ol>
	<li>Insert a guide wire in the discal space through the needle and then remove the needle.</li>
	<li>Through the inserted guide wire, slide the obturator in Kambin&#39;s triangle and anchor it over the surface of the disc space.</li>
	<li>Insert the working cannula through the obturator and, thereafter, introduce the endoscope into the Kambin&#39;s triangle. 
	NOTE: The working cannula is the beveled type with an 8 mm outer diameter. The endoscope has a 30&#176; viewing angle, a 7.3 mm outer diameter, a 4.7 mm-diameter working channel, and 251 mm of total length. The entire procedure is performed using constant saline irrigation.</li>
</ol>
5. Surgical Procedure
<ol>
	<li>Observe the epidural fat and soft tissues in the Kambin&#39;s triangle through the endoscope prior to the entry into the disc (Figure 1A).</li>
	<li>Clear the soft tissue and blood vessels over the annulus using the radiofrequency coagulator. Perform the annular fenestration with an annular cutter and enter the annulus under endoscopic vision. 
	NOTE: To avoid any injury to the exiting and traversing nerve root during the approach, the operation proceeds with continuous feedback from the patient.</li>
	<li>Obtain a half-and-half view of the epidural space and the disc space by inserting the bevel type of the cannula in the fenestrated annulus. 
	NOTE: In the dorsal half of the half-and-half, the posterior longitudinal ligament, the epidural space, and the traversing nerve root and dura can be seen. In the ventral half, the annulus and the disc ventral to the posterior longitudinal ligament can be seen.</li>
	<li>Lever the working cannula downwards to achieve an exact half-and-half view7 (Figure 2A and 2B). 
	NOTE: Using the bevel-type working cannula, it is not easy for beginners to manipulate the exiting nerve root safely, so a round working cannula can also be used (Figure 3).</li>
</ol>
6. Targeted Fragmentectomy
<ol>
	<li>After decompressing the protruded disc sufficiently, change the trajectory of working toward the symptomatic disc area. 
	NOTE: The working channel is directed toward the suprapedicular notch in the inferior-migrated disc, the epidural space in the high-canal compromised disc and foraminal space in the superior-migrated disc (Figure 3).</li>
	<li>Confirm that all free fragments of the disc are removed by checking the free-floating dural sac, the exiting root, and the traversing root, and free the epidural space by rotating the working channel and the endoscope. 
	NOTE: All patients undergo MRI on the day following the surgery (Figure 4 and Figure 5).</li>
</ol>

<ol>
	<li>Tzaan, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transforaminal+percutaneous+endoscopic+lumbar+discectomy.">Transforaminal percutaneous endoscopic lumbar discectomy.</a> Chang Gung medical journal. 30 (3), 226 (2007).</li><li>Morgenstern, R., Morgenstern, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Percutaneous+Transforaminal+Lumbar+Interbody+Fusion+(pTLIF)+with+a+Posterolateral+Approach+for+the+Treatment+of+Degenerative+Disk+Disease:+Feasibility+and+Preliminary+Results.">Percutaneous Transforaminal Lumbar Interbody Fusion (pTLIF) with a Posterolateral Approach for the Treatment of Degenerative Disk Disease: Feasibility and Preliminary Results.</a> International journal of spine surgery. 9, (2015).</li><li>Ying, 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=The+effect+and+feasibility+study+of+transforaminal+percutaneous+endoscopic+lumbar+discectomy+via+superior+border+of+inferior+pedicle+approach+for+down-migrated+intracanal+disc+herniations.">The effect and feasibility study of transforaminal percutaneous endoscopic lumbar discectomy via superior border of inferior pedicle approach for down-migrated intracanal disc herniations.</a> Medicine. 95 (8), (2016).</li><li>Schubert, M., Hoogland, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+transforaminal+nucleotomy+with+foraminoplasty+for+lumbar+disk+herniation.">Endoscopic transforaminal nucleotomy with foraminoplasty for lumbar disk herniation.</a> Operative Orthopadie und Traumat.ologie. 17 (6), 641-661 (2005).</li><li>Telfeian, A. E., Jasper, G. P., Francisco, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transforaminal+endoscopic+treatment+of+lumbar+radiculopathy+after+instrumented+lumbar+spine+fusion.">Transforaminal endoscopic treatment of lumbar radiculopathy after instrumented lumbar spine fusion.</a> PainPhysician. 18 (2), 179-184 (2015).</li><li>Kim, H. 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=Analysis+of+clinical+results+of+three+different+routes+of+percutaneous+endoscopic+transforaminal+lumbar+discectomy+for+lumbar+herniated+disk.">Analysis of clinical results of three different routes of percutaneous endoscopic transforaminal lumbar discectomy for lumbar herniated disk.</a> Worldneurosurgery. 103, 442-448 (2017).</li><li>Gore, S., Yeung, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+&amp;#34;inside+out&amp;#34;+transforaminal+technique+to+treat+lumbar+spinal+pain+in+an+awake+and+aware+patient+under+local+anesthesia:+results+and+a+review+of+the+literature.">The &amp;#34;inside out&amp;#34; transforaminal technique to treat lumbar spinal pain in an awake and aware patient under local anesthesia: results and a review of the literature.</a> International journal of spine surgery. 8, (2014).</li><li>Choi, G., Pophale, C. S., Patel, B., Uniyal, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+Spine+Surgery.">Endoscopic Spine Surgery.</a> Journal of Korean Neurosurgical Society. 60 (5), 485 (2017).</li><li>Hoogland, T., Schubert, M., Miklitz, B., Ramirez, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transforaminal+posterolateral+endoscopic+discectomy+with+or+without+the+combination+of+a+low-dose+chymopapain:+a+prospective+randomized+study+in+280+consecutive+cases.">Transforaminal posterolateral endoscopic discectomy with or without the combination of a low-dose chymopapain: a prospective randomized study in 280 consecutive cases.</a> Spine. 31 (24), E890-E897 (2006).</li><li>Ruetten, S., Komp, M., Godolias, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+extreme+lateral+access+for+the+surgery+of+lumbar+disc+herniations+inside+the+spinal+canal+using+the+full-endoscopic+uniportal+transforaminal+approach-technique+and+prospective+results+of+463+patients.">An extreme lateral access for the surgery of lumbar disc herniations inside the spinal canal using the full-endoscopic uniportal transforaminal approach-technique and prospective results of 463 patients.</a> Spine. 30 (22), 2570-2578 (2005).</li><li>Johnson, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Visual analog scale (VAS). , (2001).</li><li>Fairbank, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oswestry+disability+index.">Oswestry disability index.</a> Journal of neurosurgery Spine. 20 (2), 239 (2014).</li><li>Macnab, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+Disc+Exploration:+an+analysis+of+the+causes+of+nerve-root+involvement+in+sixty-eight+patients.">Negative Disc Exploration: an analysis of the causes of nerve-root involvement in sixty-eight patients.</a> The Journal of bone and joint surgery. 53 (5), 891-903 (1971).</li><li>Hoogland, T., van den Brekel-Dijkstra, K., Schubert, M., Miklitz, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+transforaminal+discectomy+for+recurrent+lumbar+disc+herniation:+a+prospective,+cohort+evaluation+of+262+consecutive+cases.">Endoscopic transforaminal discectomy for recurrent lumbar disc herniation: a prospective, cohort evaluation of 262 consecutive cases.</a> Spine. 33 (9), 973-978 (2008).</li><li>Yeung, A. T., Tsou, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Posterolateral+endoscopic+excision+for+lumbar+disc+herniation:+surgical+technique,+outcome,+and+complications+in+307+consecutive+cases.">Posterolateral endoscopic excision for lumbar disc herniation: surgical technique, outcome, and complications in 307 consecutive cases.</a> Spine. 27 (7), 722-731 (2002).</li><li>Kambin, P., Gellman, 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+Lateral+Discectomy+of+the+Lumbar+Spine+A+Preliminary+Report.">Percutaneous Lateral Discectomy of the Lumbar Spine A Preliminary Report.</a> Clinical Orthopaedics and Related Research. 174, 127-132 (1983).</li><li>Hoogland, T. <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+discectomy.">Percutaneous endoscopic discectomy.</a> Journal of neurosurgery. 79 (6), 967-968 (1993).</li><li>Knight, M., Goswami, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Management+of+isthmic+spondylolisthesis+with+posterolateral+endoscopic+foraminal+decompression.">Management of isthmic spondylolisthesis with posterolateral endoscopic foraminal decompression.</a> Spine. 28 (6), 573-581 (2003).</li><li>Pain, B., Telfeian, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+retrospective+evaluation+of+the+clinical+success+of+transforaminal+endoscopic+discectomy+with+foraminotomy+in+geriatric+patients.">A retrospective evaluation of the clinical success of transforaminal endoscopic discectomy with foraminotomy in geriatric patients.</a> Painphysician. 16, 225-229 (2013).</li><li>Kim, H. S., Ju, C. I., Kim, S. W., Kim, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+transforaminal+suprapedicular+approach+in+high+grade+inferior+migrated+lumbar+disc+herniation.">Endoscopic transforaminal suprapedicular approach in high grade inferior migrated lumbar disc herniation.</a> Journal of Korean Neurosurgical Society. 45 (2), 67 (2009).</li><li>Chae, K. H., 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=Strategies+for+noncontained+lumbar+disc+herniation+by+an+endoscopic+approach:+transforaminal+suprapedicular+approach,+semi-rigid+flexible+curved+probe,+and+3-dimensional+reconstruction+CT+with+discogram.">Strategies for noncontained lumbar disc herniation by an endoscopic approach: transforaminal suprapedicular approach, semi-rigid flexible curved probe, and 3-dimensional reconstruction CT with discogram.</a> Journal of Korean Neurosurgical Society. 46 (4), 312 (2009).</li><li>Anichini, 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=Lumbar+endoscopic+microdiscectomy:+Where+are+we+now?+An+updated+literature+review+focused+on+clinical+outcome,+complications,+and+rate+of+recurrence.">Lumbar endoscopic microdiscectomy: Where are we now? An updated literature review focused on clinical outcome, complications, and rate of recurrence.</a> BioMed research international. , (2015).</li><li>Gotecha, 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+of+transforaminal+percutaneous+endoscopic+discectomy+in+lumbar+disc+herniations.">The role of transforaminal percutaneous endoscopic discectomy in lumbar disc herniations.</a> Journal of craniovertebral junction &amp; spine. 7 (4), 217 (2016).</li><li>Ruetten, S., Komp, M., Merk, H., Godolias, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recurrent+lumbar+disc+herniation+after+conventional+discectomy:+a+prospective,+randomized+study+comparing+full-endoscopic+interlaminar+and+transforaminal+versus+microsurgical+revision.">Recurrent lumbar disc herniation after conventional discectomy: a prospective, randomized study comparing full-endoscopic interlaminar and transforaminal versus microsurgical revision.</a> Clinical Spine Surgery. 22 (2), 122-129 (2009).</li><li>Weir, B., Jacobs, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reoperation+rate+following+lumbar+discectomy.+An+analysis+of+662+lumbar+discectomies.">Reoperation rate following lumbar discectomy. An analysis of 662 lumbar discectomies.</a> Spine. 5 (4), 366-370 (1980).</li><li>&#xD6;sterman, H., Sund, R., Seitsalo, S., Keskim&#228;ki, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Risk+of+multiple+reoperations+after+lumbar+discectomy:+a+population-based+study.">Risk of multiple reoperations after lumbar discectomy: a population-based study.</a> Spine. 28 (6), 621-627 (2003).</li><li>Xin, G., Shi-Sheng, H., Hai-Long, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphometric+analysis+of+the+YESS+and+TESSYS+techniques+of+percutaneous+transforaminal+endoscopic+lumbar+discectomy.">Morphometric analysis of the YESS and TESSYS techniques of percutaneous transforaminal endoscopic lumbar discectomy.</a> Clinical Anatomy. 26 (6), 728-734 (2013).</li><li>Pan, Z., Ha, Y., Yi, S., Cao, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+of+transforaminal+endoscopic+spine+system+(TESSYS)+technique+in+treating+lumbar+disc+herniation.">Efficacy of transforaminal endoscopic spine system (TESSYS) technique in treating lumbar disc herniation.</a> Medical science monitor: international medical journal of experimental and clinical research. 22, 530 (2016).</li></ol>

The authors have nothing to disclose.

The study is based on the prospective analysis of 184 patients with lumbar disc disease that were managed at our institute. X-ray imaging, computed tomography (CT), and magnetic resonance imaging (MRI) were done in all cases to confirm the diagnosis and to rule out other pathologies. The findings demonstrated on the CT and MRI scans were correlated with a neurologic examination. After the proper diagnosis, patients were operated on with the mobile outside-in technique of PETLD. The exclusion criteria were the presence of...

Chronic low back pain and leg pain are common ailments in any society. The treatment modalities to combat degenerative lumbar disc diseases have been continuously evolving. The armamentarium has been wide, from open surgery and fixation to microlumbar discectomy, and now the endoscopic route1,2,3,4. The transforaminal pathway, initially suggested by Parvez Kambin, is now gradually becoming a standard of care5,6,7. The advantages of full-endoscopic spine surgeries are less soft-tissue dissection, less blood loss, reduced hospital admission days, an early functional recovery, and an enhancement in the quality of life8.
The traditional outside-in approach of PETLD, given by Schubert and Hoogland4, deals with the introduction of a working cannula in the foramen and then an enlargement of the foramen by using reamers. The rationale behind the novel technique of the outside-in approach mentioned here is that it does not solely depend on enlarging the foramen in all cases. The technique focuses on the precise placement of the working cannula within the foramen and then guiding the movement of the cannula toward the target fragment, under endoscopic vision9,10. Anatomically, there are three different routes into the transforaminal space, and if used effectively, percutaneous endoscopic spine surgery with the outside-in technique can be applied to a wider range of lumbar disc herniation. Central, paracentral, and high canal compromised Lumbar Disc Herniation (LDH) is approached by the intervertebral route; foraminal, superiorly migrated, and far lateral LDH is approached by the foraminal route, and inferiorly migrated LDH is approached by the suprapedicular route6. The advantage of this technique is that it preserves the normal anatomical structures with less discal injury, the epidural exposure is easy, and the manipulation of a working cannula in the foramen is not difficult. The technique described differs from the earlier one because it provides a precise vision of the structures within the foramen and focuses on the accurate placement of the cannula within the foramen, rather than on enlarging the foramen. The technique is equally safe as inside-out technique and provides an easy handling of structures, especially the extruded fragments. The goal of this study is to prove the versatility of this novel approach in managing different types of disc prolapse as central, paracentral, foraminal, far lateral, and up and down migration, and in high-canal compromise cases. The technique, however, demands a longer learning curve and so beginners need to be patient while learning.

<table><tbody><tr><td>Contrast dye injection</td><td>Iobrix injection, Taejoon pharm,Seoul, Korea</td><td>S.No. 1</td><td></td></tr><tr><td>0.8% indigo carmine</td><td>Carmine, Korea United Pharmaceutical, Yoenki, Korea</td><td>S.No. 2</td><td></td></tr><tr><td>30&amp;deg; endoscope</td><td>Joimax GmbH, Germany</td><td>S.No. 3</td><td></td></tr><tr><td>Radiofrequency coagulator</td><td>Elliquence, New York, USA</td><td>S.No. 4</td><td></td></tr><tr><td>Drill</td><td>Primado 2 NSK, Tochigi, Japan</td><td>S.No. 5</td><td></td></tr></tbody></table>

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.

Outcome Evaluation:
The outcome of the surgery was measured by the VAS leg pain score11, the ODI12, and the Macnab criteria13. These were measured in the preoperative period and during follow-up visits (1 week after the surgery, 3 months after the surgery, and at the last follow-up).
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A Mobile Outside-in Technique of Transforaminal Lumbar Endoscopy for Lumbar Disc Herniations

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 ...

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11.8K Views.  Nanoori Hospital. 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.

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

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Fecal Microbiota Transplantation (FMT) is a safe and highly effective treatment for recurrent and refractory C. difficile infection (CDI). Various methods of FMT administration have been reported in the literature including nasogastric tube, upper endoscopy, enema and colonoscopy. FMT via colonoscopy yields excellent cure rates and is also well tolerated. We have found that patients find this an acceptable and tolerable mode of delivery. At our Center, we have initiated a fecal transplant program for patients with recurrent or refractory CDI. We have developed a protocol using an iterative process of revision and have performed 24 fecal transplants on 22 patients with success rates comparable to the current published literature. A systematic approach to patient and donor screening, preparation of stool, and delivery of the stool maximizes therapeutic success. Here we detail each step of the FMT protocol that can be carried out at any endoscopy center with a high degree of safety and success.

Fecal Microbiota Transplantation via Colonoscopy for Recurrent C. difficile Infection

Fecal Microbiota Transplantation via colonoscopy is a safe and effective treatment for recurrent and refractory C.difficile infection. A systematic approach to patient and donor screening, preparation of stool, and delivery of the stool during the colonoscopy will maximize therapeutic success.

Fecal Microbiota Transplantation (FMT) is a safe and highly effective treatment for recurrent and refractory C. difficile infection (CDI). Various methods ...

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle screws after spinal surgery, which is a serious concern. To address this problem, diverse types of pedicle screws have been examined to identify those with good fixation strength and osseointegration in spine bone. The porcine spine is a good alternative for the human spine in the evaluation of pedicle screws due to the anatomical size, mechanical characteristics, and cost. Although several studies have reported that pedicle screws are efficient in the porcine model, no study has described detailed protocols for the evaluation of a pedicle screw using the porcine model. Here, we describe a detailed method for evaluating transpedicular screws using an in vivo porcine lumbar spine model. The technical details for anesthesia, spine surgery, and harvest provided here will facilitate with the evaluation of the transpedicular screw fixation model.

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Here, we introduce a method to evaluate transpedicular screws by using an in vivo porcine lumbar spine model.

Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle ...

Transtubular Endoscopic Posterolateral Decompression for L5-S1 Lumbar Lateral Disc Herniation

We report a novel technique for C-arm free transtubular L5 nerve decompression under CT-based navigation to reduce the radiation hazard. This procedure is performed under general anesthesia and neuromonitoring. The patient is placed in a prone position on an operating carbon table. A navigation reference frame is placed percutaneously into the contralateral sacroiliac joint or spinous process. Then, CT scan images are obtained. After instrument registration, the L5-S1 foraminal level is confirmed with a navigated probe, and the entry point is marked. Using an approximately 2 cm skin incision, the subcutaneous tissue and muscles are dissected. The navigated first dilator is aimed at the L5-S1 Kambin&#39;s triangle, and sequential dilation is performed. The 18 mm tube is used and fixed to the frame. The bone around the Kambin&#39;s triangle is removed with a navigated burr. For lateral disc herniation, the L5 nerve root is identified and retracted, and the disc fragment is removed. The navigation-guided tubular endoscopic decompression is an effective procedure. There is no radiation hazard to the surgeon or the operating room staff.

Presented here is a novel technique of C-arm free transtubular posterolateral decompression for lumbar foraminal stenosis and lateral disc herniation under O-arm navigation.

We report a novel technique for C-arm free transtubular L5 nerve decompression under CT-based navigation to reduce the radiation hazard. This procedure is ...

Neuroscience

Full-Endoscopic Transforaminal Approach for Lumbar Discectomy

With technical advancements, the full-endoscopic transforaminal approach for lumbar discectomy (ETALD) is gaining popularity. This technique utilizes various tools and instruments, including a dilator, a beveled working sleeve, and an endoscope with a 20-degree angle and 177 mm length, equipped with a 9.3-diameter oval shaft and a 5.6 mm diameter working channel. Additionally, the procedure involves using a Kerrison punch (5.5 mm), rongeur (3-4 mm), punch (5.4 mm), tip control radioablator applying a radiofrequency current of 4 MHz, fluid control irrigation and suction pump device, 5.5 mm oval burr with lateral protection, burr round, and the diamond round. During the surgery, it is essential to identify significant landmarks, including the caudal pedicle, ascending facet, annulus fibrosis, posterior longitudinal ligament, and the exiting nerve root. The steps of the technique are relatively easy to follow, especially when utilizing the appropriate instruments and having a good understanding of the anatomy. Research studies have demonstrated comparable outcomes to open microdiscectomy techniques. ETALD presents itself as a safe option for lumbar discectomy, as it minimizes tissue disruption, results in low postoperative surgical site pain, and allows for early mobilization.

The present protocol describes the full-endoscopic transforaminal approach for lumbar discectomy, which is a safe technique that does not require muscle retraction or bone removal.

With technical advancements, the full-endoscopic transforaminal approach for lumbar discectomy (ETALD) is gaining popularity. This technique utilizes ...

Full Endoscopic Transforaminal Thoracic Discectomy Operative Technique

Thoracic disc herniations are a degenerative pathology of the thoracic spine wherein a portion of nucleus pulposis herniates into the epidural space, potentially causing spinal cord or nerve root compression. Traditional surgical treatment for patients with thoracic disc herniations requires relatively invasive anterior or posterolateral approaches that involve extensive muscular dissection and removal of bone in order to access and remove the disc herniation without causing undue compression of the spinal cord. Full endoscopic thoracic discectomy is a minimally invasive technique which allows for the resection of thoracic disc herniations through a small (1 cm) incision, minimizing collateral tissue trauma and obviating the need for the extensive muscle dissection and bony removal required for traditional surgical approaches. In this article, we describe in detail the operative technique for full endoscopic thoracic discectomy and discuss the pearls and pitfalls of the technique. We also provide a review of the outcomes and complications as seen in the literature.

This protocol demonstrates the surgical technique for full endoscopic transforaminal resection of thoracic disc herniations.

Thoracic disc herniations are a degenerative pathology of the thoracic spine wherein a portion of nucleus pulposis herniates into the epidural space, ...

Full Endoscopic Interlaminar Approach for Paracentral L5-S1 Disc Herniation

The full endoscopic interlaminar approach (FEILA) is a minimally invasive technique for lumbar discectomy. It has multiple advantages over other conventional discectomy methods, including less traumatization of the soft tissues, fewer complication rates (dural injury, bleeding), rapid rehabilitation, quick return to daily life activities, and preferable cosmetic results. FEILA is a surgery with a relatively steep learning adaptation. Endoscopic surgery is a closed tubular approach, and all surgical maneuvers are performed within a uniportal single working channel. Also, the technique has not yet been standardized and well-documented. Therefore, the early learning stages of this technique may not be easy for most surgeons. Despite these, FEILA is easy, and the operation length is comparable to and even shorter than other techniques of lumbar discectomy. FEILA for lumbar discectomy could be considered a safe and effective alternative procedure for paracentral L5-S1 disc herniation. Here, we describe the technique of FEILA, including every cutoff step required to reach technical proficiency for surgeons who want to start applying this approach.

Here, we present a protocol to describe the full endoscopic interlaminar approach (FEILA) technique, including every cutoff step required to reach technical proficiency. FEILA is a surgery with a relatively steep learning adaptation. Despite this, any surgeon capable of microdiscectomy can perform FEILA with enough practice and suitable patient selection.

The full endoscopic interlaminar approach (FEILA) is a minimally invasive technique for lumbar discectomy. It has multiple advantages over other ...

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 ...

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 ...

Full-Endoscopic Foraminoplasty and Lumbar Discectomy for Single-Level Lumbar Disc Herniation

The Transforaminal Endoscopic Surgical System (TESSYS) technique has gained popularity for the treatment of lumbar disc herniations. Foraminoplasty is the key procedure in TESSYS. However, it requires advanced skills and long-term learning, which hinder its widespread adoption among surgeons. Recently, the introduction of full-endoscopic solutions has made the process more manageable. The main difference from traditional single-portal endoscopic surgery is that full-endoscopic surgery is equipped with a larger working channel, allowing full visualization of foraminoplasty and decreasing reliance on intraoperative fluoroscopy. Recently, published studies have shown that full-endoscopic foraminoplasty and lumbar discectomy (FEFLD) could achieve comparable results to conventional microdiscectomy in terms of pain relief and functional outcomes, while enhancing postoperative recovery. This study describes the technique of FEFLD in detail, including every crucial step, such as patient positioning, puncture trajectory, endoscopic dissection of the superior articular process (SAP), endoscopic foraminoplasty, and more. We hope this will be helpful to beginners who wish to apply this approach.

Compared to conventional transforaminal endoscopic surgery, full-endoscopic foraminoplasty and lumbar discectomy (FEFLD) is a unique technique that allows full visualization of foraminoplasty and reduces the need for intraoperative fluoroscopies. This article describes the surgical steps involved in the FEFLD technique, shedding light on surgical tips and potential pitfalls to ensure outstanding performance.

The Transforaminal Endoscopic Surgical System (TESSYS) technique has gained popularity for the treatment of lumbar disc herniations. Foraminoplasty is the ...

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

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Fecal Microbiota Transplantation via Colonoscopy for Recurrent C. difficile Infection

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Transtubular Endoscopic Posterolateral Decompression for L5-S1 Lumbar Lateral Disc Herniation

Full-Endoscopic Transforaminal Approach for Lumbar Discectomy

Full Endoscopic Transforaminal Thoracic Discectomy Operative Technique

Full Endoscopic Interlaminar Approach for Paracentral L5-S1 Disc Herniation

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

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

Unilateral Biportal Endoscopy for the Treatment of Lumbar Disc Herniation

Full-Endoscopic Foraminoplasty and Lumbar Discectomy for Single-Level Lumbar Disc Herniation