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 segmental instability, spondylolisthesis of more than grade 1, and a presence of significant spinal stenosis. A written informed consent was obtained from all patients.
The critical steps in the above-described technique are the precise placement of a working cannula in the foramen and obtaining a half-and-half view of the foramen and the disc space. The next critical step is directing the working cannula within the foramen toward the target fragment. The technique described here is different from the earlier described outside-in technique by Schubert and Hoogland4 that needed reaming. In the current protocol, the working cannula is placed in the Kambin&#39;s triangle (Figure 1) to allow mobility toward the target fragment as per location. In this technique, the epidural fat and soft tissue structures can be adequately visualized prior to entering the disc space. Entering the disc space under vision is another critical step and prevents any further discal injury and migration of the disc fragment. Following the intervertebral, foraminal or suprapedicular route, depending on the location of the target fragment, is next critical step6. Thus, foraminoplasty is required in only a small subset of the patients.
The described technique has several advantages over previously described techniques. Foremost is the wide variation in the location of the prolapsed disc that is effectively managed by the mobile outside-in technique. The varied locations of the disc include central, paracentral, foraminal, far lateral up- and down-migrated, as well as ones with canal compromise.6 The initial landing within the foramen is the most crucial part and gives the surgeon an overall view of the foramen. It gives the flexibility to move the cannula in different directions as per the need of the prolapsed disc. Another major advantage is that the annulus is entered under vision, and so further damage to the disc or migration of the fragment by blind puncture is avoided. The vision of the structures within the foramen is always better in an outside-in technique compared to inside-out technique, the extruded disc fragment is handled early, and the mobilization of the cannula is more comfortable and enables handling the up- and down-migrated discs20,21. The outside-in technique permits to target the fragment specifically and so foraminoplasty is needed in selected patients only. In a total of 190 levels operated on with this technique, drilling was required in only 46 patients (25%). Foraminoplasty was mostly required in those with a significant down migration and those with canal compromise. Part of the superior articular process and the upper part of the pedicle were drilled to create adequate space. Using curved forceps and a probe further aid in removing the migrating fragment. We have successfully utilized the mobile outside-in approach to manage all different types of lumbar disc herniations. The use of the mobile outside-in technique merits a special mention when used for a down-migrated disc, which is usually considered to be difficult for endoscopy. The authors managed 38 patients with down-migrated fragments. Of these, an excellent outcome according to the Macnab criteria was seen in 23 patients (60.5%) and good outcome in the remaining 15 patients (39.5%).
We did not find any major limitations to the technique presented in this article. Of course, the outside-in technique of PETLD has a learning curve which beginners need to take into account. As compared to earlier isolated reports mentioning the risk of injury to neurovascular and ligamentous structures in the outside-in technique7,8, our experience has shown that the outside-in technique with selective foraminotomy is equally safe and effective compared to earlier described outside-in techniques. This technique is different from earlier described outside-in techniques and does not depend solely on enlarging the foramen4,27,28. The earlier described outside-in technique by Schubert and Hoogland mentions enlargement of the foramen as a usual component in all the patients4. The technique presented here focuses on the accurate placement of the cannula toward the target fragment, thus needing an enlargement of the foramen in selected patients only. Therefore, the technique provides a better overall view of the foramen and its surrounding structures. The wide range of disc prolapses, including canal compromise, being effectively managed by this technique affirms that there is no contraindication to the outside-in technique.
The future applications of the described technique are for a wide array of lumbar disc prolapse. Even patients with high-canal compromise and a down-migrated disc can be adequately managed by PETLD. Thus, the horizon of the technique is on the rise. By precisely targeting the compressing element of the disc, this technique can provide an optimum vision within the foramen and help in achieving the desired results.
The mobile outside-in technique of PETLD can be used to deal with all types of lumbar disc herniation, including high-canal compromise, due to the mobility of the working cannula toward the target point. It does come with a learning curve and requires a thorough knowledge of the spine anatomy. This technique can be applied to all types of lumbar disc herniation and at all lumbar levels.

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 border="0" cellpadding="0" cellspacing="0" width="651">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:176px;">Contrast dye injection</td>
			<td style="width:347px;">Iobrix injection, Taejoon pharm,Seoul, Korea</td>
			<td align="right" style="width:65px;">S.No. 1</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">0.8% indigo carmine</td>
			<td>Carmine, Korea United Pharmaceutical, Yoenki, Korea</td>
			<td align="right">S.No. 2</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:176px;">30 degree endoscope</td>
			<td>Joimax GmbH, Germany</td>
			<td align="right">S.No. 3</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Radiofrequency coagulator</td>
			<td>Elliquence, New York, USA</td>
			<td align="right">S.No. 4</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Drill</td>
			<td>Primado 2 NSK, Tochigi, Japan</td>
			<td align="right">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).
Baseline Characteristics:
The mean age of the study group was 50 &#177; 16 years and the male/female ratio was 2:1. The mean follow-up of the study 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;L5: 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 demographic data and the baseline characteristics, including the preoperative MRI characteristics and the intraoperative findings, are summarized in Table 1. The mean operative time was 35 &#177; 12 (25&#8211;56) min and the mean hospital stay was 1.2 &#177; 0.5 (1&#8211;3) days.
Clinical Outcome: 
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. The improvement in the VAS score and the ODI was noticed immediately after the surgery and remained statistically significant at the follow-up (Table 2, Figure 6). The motor improvement was complete in almost all patients. According to the Macnab criteria, 75 patients (40.8%) had excellent results, while good results were seen in 104 patients (56.5%), and the remaining 5 patients (2.7%) had fair results. Recurrence was seen in 15 out of the 190 levels that were operated on (7.89%); out of these, 11 patients underwent revision PETLD (5.98%), while 4 patients underwent an open foraminotomy (2.17%).
Back pain and leg pain have troubled human for ages. The surgical approach to lumbar disc disease has been evolving. The main advantage of percutaneous endoscopic spine surgery is to preserve the normal anatomical structures as much as possible, thereby maintaining the functional status as it was prior to the surgery. PETLD has gained significant importance in the last few years, owing to the extensive work done on it all around the globe6,7,14,15,16. The early results have been promising as compared to microdiscectomy, with early mobilization, less blood loss, a smaller incision, better pain relief, and a better long-term outcome with a good quality of life6,7,17,18. The surgical armamentarium of the transforaminal route is quite wide, with nearly all types of herniations as central, paracentral, foraminal, far lateral, and superior and inferior migrated discs being managed by it efficiently19,20,21,22,23.
In previous studies, Tzaan showed a good or excellent outcome in 89% of his patients1, while Yeung and Tsou achieved a 90% patient satisfaction rate after transforaminal surgery on 307 patients15. Similarly, Ruetten et al. were successful in 79% of their endoscopic discectomies in patients with recurrent lumbar disc herniation24. In 2013, a study by Jasper et al. focused on geriatric patients with lumbar disc disease that were managed by transforaminal endoscopy19. The results were good in 71.4% as per the Macnab criteria, and the VAS score decreased from 9.2 in the preoperative period to 2.63 at the 6 month follow-up. The recurrence rate in the described outside-in technique with a mean follow-up of 19 &#177; 6 months was 7.89%. This stands well in the range of the previously reported recurrence rate of 5 - 18%14,25,26. Schubert and Hoogland have shown a recurrence rate of 3.6% on a study population of 611 patients4, while Hoogland et al.14 have shown that the recurrence rate can vary depending on the extent of the follow-up. While 7 out of the total 262 operated patients in their study developed early recurrence within 3 months post-surgery, by the end of 2 years after surgery, the total recurrence cases had increased to 11 (4.62%).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57999/57999fig1.jpg" /> 
Figure 1: Intraoperative endoscopic view of the outside-in transforaminal approach. (A) This panel shows an initial endoscopic view of the transforaminal space under the outside-in approach, with (a) the facet and (b) soft tissues in the foramen over the disc. (B) This panel shows the endoscopic view after the clearing of the transforaminal space by using radiofrequency, with (a) the foraminal ligament, (b) the suprapedicular notch area, (c) the cranial foraminal area, (d) the epidural area, and (e) the disc. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57999/57999fig1large.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/57999/57999fig2.jpg" /> 
Figure 2: Illustrative surgical view of the cannula placement during a transforaminal surgery. (A) This panel shows the initial placement of the cannula in the transforaminal approach. (B) This panel shows the downward levering of the working cannula to achieve a half-and-half view. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57999/57999fig2large.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/57999/57999fig3.jpg" /> 
Figure 3: Illustrative surgical view of a percutaneous endoscopic transforaminal lumbar discectomy. (A) This panel shows the suprapedicular route. (B) This panel shows the intervertebral route. (C) This panel shows the foraminal route. (D) This panel shows the round cannula placement for the far lateral disc. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57999/57999fig3large.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/57999/57999fig4.jpg" /> 
Figure 4: MR images of a patient with an inferior-migrated disc. (A) These are preoperative T2-weighted sagittal and axial images showing a high inferior-migrated disc prolapse at L4&#8211;L5 level with a significant compression on the right side. (B) These are postoperative T2-weighted sagittal and axial images showing the complete fragment removal using the outside-in technique. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57999/57999fig4large.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/57999/57999fig5.jpg" /> 
Figure 5: MR images of a patient with a high-canal compromise. (A) These are preoperative T2-weighted sagittal and axial images showing a high-canal compromise with a disc prolapse at L3&#8211;L4 level. (B) These are postoperative T2-weighted sagittal and axial images showing the decompressed thecal sac with the complete fragment removal. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57999/57999fig5large.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/57999/57999fig6.jpg" /> 
Figure 6: Clinical outcome of the outside-in technique of transforaminal endoscopy. The y-axis represents the score of the visual analog scale (VAS) and the Oswestry Disability Index (ODI), while the x-axis represents the time period. (A) This graph shows the VAS for leg pain. (B) This graph shows the ODI. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57999/57999fig6large.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>Factors</td>
			<td>Patients (n = 184)</td>
		</tr>
		<tr>
			<td>Age (years)</td>
			<td>50&#177;16 (15-86)*</td>
		</tr>
		<tr>
			<td>Male/female ratio</td>
			<td>2:01</td>
		</tr>
		<tr>
			<td>Levels involved (n=190)</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;L1-L2</td>
			<td>4 (2.1)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;L2-L3</td>
			<td>17 (9)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;L3-L4</td>
			<td>27 (14.2)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;L4-L5</td>
			<td>123 (64.7)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;L5-S1</td>
			<td>19 (10)&#450;</td>
		</tr>
		<tr>
			<td>Type of Disc Prolapse</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Central</td>
			<td>15 (7.9)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Paracentral</td>
			<td>75 (39.5)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Foraminal</td>
			<td>29 (15.3)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Far Lateral</td>
			<td>16 (8.4)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Superior migrated</td>
			<td>8 (4.2)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Inferior migrated</td>
			<td>38 (20)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;High canal compromise</td>
			<td>9 (4.7)&#450;</td>
		</tr>
		<tr>
			<td>Follow-up (months)</td>
			<td>19&#177;6 (9-29)*</td>
		</tr>
		<tr>
			<td>MacNab criteria</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Excellent</td>
			<td>75 (40.8)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Good</td>
			<td>104 (56.5)&#450;</td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;Fair</td>
			<td>5 (2.7)&#450;</td>
		</tr>
		<tr>
			<td>Recurrence</td>
			<td>15 (7.89)&#450;</td>
		</tr>
		<tr>
			<td>Drilling required</td>
			<td>46 (24.2%)</td>
		</tr>
		<tr>
			<td colspan="2">*All values expressed as mean &#177; standard deviation (range). &#450; All values expressed as number (%).</td>
		</tr>
	</tbody>
</table>
Table 1: Patient characteristics of the mobile outside-in technique.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Parameter</td>
			<td>Preop</td>
			<td>Post op</td>
			<td>P value</td>
			<td>3 months</td>
			<td>P value</td>
			<td>Final follow up</td>
			<td>Pvalue</td>
		</tr>
		<tr>
			<td>Visual analogue scale(VAS)</td>
			<td>7.51&#177;0.99</td>
			<td>2.76&#177;0.71</td>
			<td>&#60;0.0001</td>
			<td>1.96&#177;0.83</td>
			<td>&#60;0.0001</td>
			<td>1.73&#177;0.85</td>
			<td>&#60;0.0001</td>
		</tr>
		<tr>
			<td>Oswestry disability index(ODI)</td>
			<td>69.66&#177;8.25</td>
			<td>34.41&#177;5.32</td>
			<td>&#60;0.0001</td>
			<td>26.47&#177;5.56</td>
			<td>&#60;0.0001</td>
			<td>23.15&#177;5.83</td>
			<td>&#60;0.0001</td>
		</tr>
	</tbody>
</table>
Table 2: Comparative analysis of the preoperative and postoperative values of the visual analog scale and the Oswestry Disability Index.

Watch this Scientific Journal Video about A Mobile Outside-in Technique of Transforaminal Lumbar Endoscopy for Lumbar Disc Herniations at JoVE.com

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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Nanyang Technological University

Research

JoVE Journal

Medicine

11.7K 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

Fecal Microbiota Transplantation via Colonoscopy for Recurrent C. difficile Infection

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.

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

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

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

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Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

The purpose of this article is to provide image-guidance for minimally invasive transforaminal interbody fusion.

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Targeting Gray Rami Communicantes in Selective Chemical Lumbar Sympathectomy

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

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

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This protocol provides guidance on how to perform high resolution video rasterstereography and treadmill gait analysis on patients after lumbar fusion surgery to obtain results about altered variables of gait and posture. These observed changes can then be correlated with the patient-reported outcome measure of pain relief. The rasterstereographic device projects lines of parallel light onto the surface of the tested subject&#39;s back. The deformation of these lines is recognized by the device. From these data, a special software then generates a 3-D profile based on the principle of triangulation. With an inaccuracy of only 0.2 mm it can measure changes in posture at very high precision. Gait and stance parameters are recorded using a treadmill equipped with an electric sensor mat that contains 10,200 miniature force sensors in the registering zone under the belt. Initial walking speed on the treadmill is 0.5 km/h. Speed is then gradually increased by increments of 0.1 km/h until each subject reaches his or her individual maximum well tolerable walking speed. At this speed, parameters are recorded during a 20 s measurement interval. Subjects are tested barefoot and without holding a handrail. Among various other parameters, stride width, step length, stance phase and foot rotation are measured. Both methods used reportedly have a high intra- and inter-observer reliability. The advantage of these highly accurate techniques is that they offer an objective and very detailed perspective on changes in the patient&#39;s posture and gait. Due to the amount of data generated, these techniques are, however, not so much suitable for everyday routine use, but rather interesting to scientifically evaluate long term alterations in posture and gait in patients like for example after lumbar fusion surgery.

Here, we present a protocol to analyze the posture and the gait of patients after lumbar fusion surgery by means of high-resolution video rasterstereography and a treadmill equipped with an integrated sensor mat. Allowing critical functional postoperative evaluation on a less subjective level may enhance accuracy and reliability of indication for surgery.

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LECS has natural advantages in the treatment of G-GISTs that are less than 5 cm in size. The accurate estimation of tumor location and boundary greatly improves the complete resection rate of tumors. The risk of tumor rupture is substantially reduced, and the long-term prognosis of patients is significantly improved. The process allows for accurate resection of the tumor, maximum preservation of normal gastric tissue and organ function, and avoids postoperative gastric deformation. The patient's postoperative rehabilitation is greatly accelerated, and oral feeding can resume on the day of the operation. The specimen is taken out through the mouth to avoid the need for an extended abdominal incision. This greatly reduces the patient's postoperative pain and scarring. The method greatly shortens the postoperative hospital stay (i.e., discharge is possible on the day after the operation), increasing the turnover of hospital beds.

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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 ...

3D Printing Model of a Patient's Specific Lumbar Vertebra

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical field of view but also protect the patient&#39;s spinal nerves from injury. Digital models play an important role in the pre-and intra-operation of SDR, because they can not only make doctors more familiar with the anatomical structure of the surgical site, but also provide precise surgical navigation coordinates for the manipulator. This study aims to create a 3D digital model of a patient-specific lumbar vertebra that can be used for planning, surgical navigation, and training of the SDR operation. The 3D printing model is also manufactured for more effective work during these processes.
Traditional orthopedic digital models rely almost entirely on computed tomography (CT) data, which is less sensitive to soft tissues. Fusion of the bone structure from CT and the neural structure from magnetic resonance imaging (MRI) is the key element for the model reconstruction in this study. The patient&#39;s specific 3D digital model is reconstructed for the real appearance of the surgical area and shows the accurate measurement of inter-structural distances and regional segmentation, which can effectively help in the preoperative planning and training of SDR. The transparent bone structure material of the 3D-printed model allows surgeons to clearly distinguish the relative relationship between the spinal nerve and the vertebral plate of the operated segment, enhancing their anatomical understanding and spatial sense of the structure. The advantages of the individualized 3D digital model and its accurate relationship between spinal nerve and bone structures make this method a good choice for preoperative planning of SDR surgery.

This study aims to create a 3D-printed model of a patient-specific lumbar vertebra, which contains both the vertebra and spinal nerve models fused from high-resolution computed tomography (HRCT) and MRI-Dixon data.

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical ...

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 ...