Technical Tips for Percutaneous Transforaminal Endoscopic Discectomy: a three-step maneuver for puncture and early clinical experience

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The transforaminal puncture method currently employed in PTED depends on a constant distance from the midline and estimated angles in anteroposterior and craniocaudal directions. TSMP is an alternative concept of puncture based on Kambin’s triangle. TSMP references the natural anatomy of patients to progressively advance the needle to target. We herein discribed a three-step maneuver for puncture (TSMP) in PTED, which is possible to introduce the needle more safely and gain easy access to the herniated disc. Methods: We performed a retrospective review of 30 patients who underwent PTED using TSMP for lumbar disc herniation (LDH) and met inclusion criteria from January 2018 to September 2018. The primary outcome, leg or back pain, was assessed using Visual Analogue Scale (VAS). Patient surgical satisfaction was measured at 12 months post surgery using a five-point Likert scale. Potential prognostic factors measured were demographic characteristics, duration of symptom (DOS), and involved levels. Statistical analysis was performed using Fisher exact test and t-test.. Results: Preoperative mean VAS was 7.6 ± 1.19, which decreased to 1.4 ± 0.97 at12 months following treatment (P < .0001). Rates of surgical satisfaction per Likert scale were as follows: very satisfied and satisfied in 26 patients (86.7%). VAS scores at 12 months varied significantly between L4-L5 level surgery and L5-S1 level surgery groups (P < .01). Conclusion: TSMP is a reliable technique for puncture into the intervertebral foramen. Orthopedics Percutaneous Transforaminal Endoscopic Discectomy Lumbar Disc Herniation Three-Step Maneuver for Puncture Kambin’s Triangle Approximating Rectangle Visual Analogue Scale Figures Figure 1 Figure 2 Figure 3 Figure 4 Background For sciatica with lumbar disc herniation (LDH), surgery is recommended when patients are refractory to conservative treatment [[ 1 – 4 ]] . At present, conventional microdiscectomy (CMD) is still the standard surgical procedure for LDH [[ 5 – 7 ]] . In the past few decades, minimally invasive spine surgery (MISS) has become increasingly popular all over the world [[ 8 ]] .Percutaneous transforaminal lumbar discectomy (PTED) is one of the popular minimally invasive procedures for the treatment of lumbar disc herniation [[ 9 ]] . In 1987, Kambin, et al. [[ 10 ]] introduced the safe triangle (i.e., Kambin’s triangle) of percutaneous posterolateral extracanal approach for the management of LDH, reporting arthroscopic microdiscectomy in 1992 [[ 11 ]] . Based on the concept of the “inside-out,” Yeung, et al. [[ 12 – 14 ]] developed the technique of Yeung Endoscopic Spine System (YESS). Surgeons maneuvered endoscopic instruments into the intervertebral disc via the Kambin’s triangle and progressively removed the herniated disc from within. In contrast, Hoogland, et al. [[ 15 ]] , based on the concept of “outside-in,” proposed the Thomas Hoogland Endoscopic Spine System (THESSYS): inserting the working channel into the spinal canal via intervertebral foramen with plasty, excising the herniated disc from the outside to the inside, releasing and decompressing the compressed nerve root. Since then, PTED has been widely used around the world, and the results of multiple randomized controlled trials and systematic reviews [[ 16 – 19 ]] comparing the functional and pain improvements of PTED and CMD have revealed no significant difference between the two. PTED has the advantages of less trauma, less bleeding, quick recovery, less impact on spinal stability, and operation under local anesthesia [[ 20 ]] . Gibson, et al. [[ 21 ]] and Gadjradj, et al. [[ 22 ]] have further elaborated on the PTED. With respect to PTED, safe and accurate puncture is one of the key steps for determining the difficulty of surgery and clinical outcomes [[ 23 ]] . At present, the transforaminal puncture method in PTED, nevertheless, still depends on a constant distance from the midline and estimated angles in anteroposterior and craniocaudal directions [[ 22 , 24 ]] . PTED is usually performed with the aid of intraoperative C-arm imaging. However, the C-arm does not provide sufficient information to determine the optimal depth, angle and other important parameters for safe puncture. Therefore, the surgeon needs to integrate limited information during the process of puncture, which requires high-level ability in spatial thinking, factoring in the individual experiences of the surgeon. For beginners, redo punctures are almost inevitable; unfortunately, multiple punctures necessitate increased fluoroscopy time, operation time, and radiation exposure to doctors and patients, along with the increased risk of nerve injury [ [25, 26] ] . One of the urgent difficulties in PTED is how to locate and puncture quickly, accurately and safely. With the three-step maneuver for puncture (TSMP) developed by the coauthors, it is possible to introduce the needle more safely and gain easy access to the herniated disc. Methods Rationale and Anatomy Kambin, et al. [[ 10 ]] reported a safe triangular working area (i.e., Kambin’s triangle) consisting of a two-dimensional anatomic right triangle over the lateral recess of the lumbar spine [[ 27 , 28 ]] . The triangle is bordered by the superior endplate of the lower vertebra (i.e., base of the triangle), the superior articular facet (i.e., the height of the triangle) and the exiting superior nerve root (i.e., the hypotenuse of the triangle) in a twodimensional plane (Fig. 1 ). Within this triangular area, there is no traversing nerve root or visceral structure of critical importance. Needles, guidewires and other instruments can be introduced through the described area with greater confidence in reduced incidence of complication, such as violation of the nerve root, etc. Surgical Procedures Anesthesia and Positioning In general, PTED is performed under local anesthesia, and, if necessary, light sedation may be administered. Under light sedation alone, a patient might be responsive. In order to facilitate the execution of TSMP, the patient will be placed in a prone position on the radiolucent table. With respect to the lateral position, there may be many advantages, such as a larger safety zone with respect to the dura, less bleeding, and so on [[ 20 , 29 ]] . Another advantage of the prone position is that the position of patients is more stable, allowing less movement. Further, surgeons are quite familiar with the anatomy and its landmarks in this position. Target and entry point Using the mobile C-arm for anteroposterior and lateral radiographic control, the target and the entry point will be accurately positioned for operators. The target is located at the intersection of the superior endplate line of the lower vertebra and the inner line of lower vertebral pedicle in anteroposterior projection (Fig. 2 A), or at the intersection of the trailing line of the lower vertebral body and the superior endplate line of the lower vertebra in lateral projection (Fig. 2 B). The area of needle insertion is located on the patient’s posterolateral side, which is an approximating rectangle (AR) formed by the line of spinous process, the line of transverse process, the superior endplate line of the upper vertebra and the superior endplate line of the lower vertebra in lateral projection (Fig. 3 ). During the operation, the appropriate entry point should be determined in the AR according to the location of the herniated disc: (1) The closer the position of the disc is to the center, the closer the needle point is to the ventral side; (2) The closer the position of the disc is to the cephalad side, the closer the needle point is to the caudal side. The line connecting the entry point to the target is the surgical approach (SA). TSMP After layer-by-layer local infiltration of anesthetic to the skin of the entry point with 1% lidocaine, an 18-gauge spinal needle will be inserted. Components of the TSMP are as follows: Step 1: The needle is inserted through the appropriate entry point and advanced toward the spinous process by inches. The approach of puncture is parallel to the projected line of the SA on the back bed. When the needle tip reaches the bony structure (i.e., spinous process), the location of the tip will be determined by using biplanar C-arm images. The process is shown in Fig. 4 A. Step 2: The needle is pulled out an appropriate distance (about 3 to 5 cm). Then, after raising the needle tail properly, the needle will be advanced toward the superior articular facet. When the needle tip reaches the bony structure (i.e., superior articular facet), the location of the tip will be determined by using biplanar C-arm images. The process is shown in Fig. 4 B. Step 3: The needle is pulled out an appropriate distance again (about 2 to 3 cm). Then, after raising the needle tail properly, the needle will be advanced toward the target, and the surgeon will feel the needle tip slide into the intervertebral foramen along the superior articular facet. When the needle tip reaches the bony structure (i.e., target), the location of the tip will be determined by using biplanar C-arm images. The process is shown in Fig. 4 C. Foraminoplasty, placing of the working channel and introducing the endoscope The typical surgical procedures, including foraminoplasty, introduction of the working channel and endoscope, removal of the target disc and decompression of the nerve, continue, consistent with conventional techniques of PTED [[ 15 , 22 , 30 ]] . Clinical Materials and Statistical Analysis We performed a retrospective review of 30 patients who underwent PTED using TSMP for LDH from January 2018 to September 2018. The inclusion criteria were as follows: (1) age 18 to 70 years; (2) single-level surgery; (3) informed consent; and (4) at least one year after surgery. Exclusion criteria consisted of: (1) previous surgery on the same or adjacent disc level; (2) spondylytic or degenerative spondylolisthesis; (3) severe somatic or psychiatric illness; and (4) history of psychiatric or psychological disorder. The primary outcome, leg or back pain, was assessed using the Visual Analogue Scale (VAS) [[ 31 ]] . Surgical satisfaction was measured using a five-point Likert scale [[ 32 ]] , varying from “very satisfied” (5 points) to “very unsatisfied” (1 point). The following potential prognostic factors were measured: (1) demographic characteristics (e.g., age and gender); (2) duration of symptom (DOS); (3) involved levels. Statistical analysis was performed using Fisher exact test and t-test, and the P value < .05 was regarded as statistically significant. Ethical approval has been granted by the Ethics Committee of Fujian Medical University Union Hospital, Fuzhou, China (2018YF010-02). Results There were 30 patients with LDH who met the inclusion criteria and had undergone PTED using TSMP. The demographic findings are summarized in Table 1 . The followup time was 1 year. The preoperative mean VAS was 7.6 ± 1.19, which decreased to 1.4 ± 0.97 at 12 months following treatment (P < − .0001). Based on a five-point Likert scale, the rates of surgical satisfaction were as follows: very satisfied and satisfied in 26 patients (86.7%), general in three patients (13.3%). Three recurrent disc herniations of adjacent segmental levels were observed in the L5-S1 group at eight and 12 months after surgery. One of the patients with recurrence underwent tubular microdiscectomy at 12 months after undergoing PTED using TSMP. According to the subgroup analysis, there were significantly different VAS scores at 12 months postoperatively between the L4-L5 group and the L5-S1 group (P < .01). There were no significant influences at 12 months after PTED on the primary outcome from other factors, including gender, age, body mass index (BMI), and DOS (Table 2 ). Table 1 Demographic Characteristics Data No. Percent Gender Male 17 56.70% Female 13 43.30% Age ≤ 40 yrs 8 26.70% ༞40 yrs 22 73.30% BMI (kg/m 2 ) ≤ 23 12 40% ༞23 18 60% Side Right 9 30% Left 21 70% Duration of symptoms ≤ 6 months 18 60% ༞6 months 12 40% Level L4/5 14 46.70% L5/S1 16 53.30% Location Central 11 36.70% Lateral 7 23.30% Foraminal 12 40% 5-Point Likert scale (12 months following treatment) ༞3 26 86.7% ≤ 3 4 13.3% Table 2 Primary Outcome and Clinical Factors Variable Means ± Standard deviation(SD) Sample P value Confidence interval(CI) Visual Analogue Scale (VAS) Preoperative 7.6 ± 1.19 30 0.20 [-1.09, 0.24] Age ༞40 yrs 1.55 ± 1.06 22 Male 1.35 ± 0.79 17 > 0.60 [-0.99, 0.61] Female 1.54 ± 1.20 13 BMI* ≤23 1.75 ± 0.97 12 > 0.10 [-0.21, 1.27] BMI ༞23 1.22 ± 0.94 18 DOS* ≤6 months 1.61 ± 0.98 18 > 0.20 [-0.29, 1.18] DOS ༞6 months 1.17 ± 0.94 12 L4/5 0.93 ± 0.62 14 < 0.01 [-1.59, -0.30] L5/S1 1.88 ± 1.02 16 *BMI, Body Mass Index; DOS, duration of symptoms Discussion Accurate location for puncture is an essential step in most spinal surgery and is especially important to PTED. As for the conventional procedures of PTED, transforaminal puncture still depends on a constant distance from the midline and the estimated angles in anteroposterior and craniocaudal orientations [[ 15 , 22 , 30 ]] . It is complicated and difficult for beginners to insert a needle into the intervertebral foramen relying on the traditional method. Therefore, the learning curve for PTED is often described as steep [[ 33 ]] . Accurate needle puncture and trajectory is essential to safe, successful surgery. If the puncture were inaccurate, increased puncture frequency and increased fluoroscopy time would be inevitable, thus increasing radiation exposure to doctors and patients. Notably, radiation exposure has been found to increase the risk of some types of cancer for exposed surgeons [[ 34 ]] . Han, et al. [[ 35 ]] developed the obturator guiding technique in order to enhance safety and reduce drawbacks associated with the needle insertion process. The traditional technique, nevertheless, still depends on the previously described distance and angles. In 2015, Fan, et al. [[ 36 ]] designed and produced the He’s lumbar location system (HELLO), which could improve puncture accuracy and reduce fluoroscopy time in the performance of PTED. However, the surgeon is required to repeatedly adjust the positioner and the C-arm for fluoroscopy, which amounts to extra time-consuming steps. Their system has not really been popular all over the world. Therefore, based on the anatomy of spine, this article introduced a simple and more accessible three-step maneuver for puncture (TSMP) in PTED. TSMP is a three-step maneuver that builds on the concept of needle puncture site and trajectory determination based on the principles of Kambin’s triangle. First, accurate direction of the puncture is confirmed by inserting the needle horizontally. Then by gradually raising the needle tail in the manner described, the superior articular facet and the intervertebral foramen are sequentially located. Finally, the needle tip slides into the intervertebral foramen to reach the target superior articular facet. In this study, we performed a retrospective review on patients who underwent PTED using TSMP for LDH. Patients’ sciatica was significantly relieved at 12 months after PTED using TSMP. By subgroup analysis, there were better VAS scores about 12 months postoperatively in the L4-L5 group compared to the L5-S1 group (P < .01). The reason for this result may be that PTED performed in L5-S1 group was more easily influenced by iliac crest. For patients with the L5/S1 disc herniation, especially in case of high iliac crest, there are differences in the operation due to the anatomical obstruction: 1) require a more medial placement of the entry point; 2) a resection of the lateral one fourth of the facet joint [ 14 ] . TSMP relies on the natural anatomy of the individual patient to progressively deliver the needle to the target. For this reason, TSMP could prove to be a more stable surgical technique compared than the traditional puncture method. However, there are several limitations in our study: (1) The appropriate entry point should be determined in the AR according to the location of the herniated disc, but operators cannot locate the most accurate entry point through TSMP at present. (2) Pragmatic, precise and prospective RCT, with sufficient samples and long-term followup, comparing PTED using TSMP to conventional microdiscectomy, was not performed. Hence, comparing with other procedures, the efficacy and safety of PTED using TSMP need to be further evaluated. Conclusions TSMP is a stable surgical technique for inserting the needle into the intervertebral foramen. Patients who underwent PTED using TSMP fared significantly better with regard to leg and back pain at 12 months after surgery. Given these potential advantages, more research is needed to confirm the efficacy and safety of PTED using TSMP. Declarations ABBREVIATIONS: LDH , lumbar disc herniation; CMD , conventional microdiscectomy; MISS , minimally invasive spine surgery; PTED , percutaneous transforaminal endoscopic discectomy; YESS , Yeung Endoscopic Spine System; THESSYS , Thomas Hoogland Endoscopic Spine System; TSMP , three-step maneuver for puncture; AR , approximating rectangle; SA , surgical approach; VAS , Visual Analogue Scale; DOS , duration of symptom Ethics approval and consent to participate: This study has been granted by the Ethics Committee of Fujian Medical University Union Hospital, Fuzhou, China (2018YF010-02). Consent for publication: Yes Availability of data and materials: Through the email( [email protected] ) to contact us for accessing data. Competing interests: none Funding: This work was funded by Technology and Innovation Foundation of Fujian, China (grant no 2018Y9060 to CM) Authors' contributions: Conception or design of the work: Chun Mei Chen Acquisition of data: Shao Xiong Chen Analysis of data: Shao Xiong Chen Interpretation of data: Ze Yan Liang Drafting the work: Ze Yan Liang Revising the work for valuable intellectual content: Rui Wang Final approval of the version: Chun Mei Chen Acknowledgements: none References Konstantinou K, Dunn K: Sciatica: review of epidemiological studies and prevalence estimates . Spine 2008, 33 (22):2464-2472. Jacobs WC, Arts MP, van Tulder MW, Rubinstein SM, van Middelkoop M, Ostelo RW, Verhagen AP, Koes BW, Peul WC: Surgical techniques for sciatica due to herniated disc, a systematic review . 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Step 2: Needle is pulled out to appropriate length. Then, after raising needle tail properly, needle will be advanced toward superior articular facet (4B). Step 3: Needle is pulled out to appropriate length again. Then, after raising needle tail properly, needle is advanced toward the target, and needle tip will slide into the intervertebral foramen along superior articular facet (4C).","description":"","filename":"Figure4.tif","url":"https://assets-eu.researchsquare.com/files/rs-18310/v1/Figure 4.tif"},{"id":13495402,"identity":"c1d2b5a8-e303-4c67-b280-8b7abf9acf75","added_by":"auto","created_at":"2021-09-16 22:45:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3386238,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-18310/v1/cf85859f-6f29-49e3-90ab-874e14d73026.pdf"}],"financialInterests":"","formattedTitle":"Technical Tips for Percutaneous Transforaminal Endoscopic Discectomy: a three-step maneuver for puncture and early clinical experience","fulltext":[{"header":"Background","content":" \u003cp\u003eFor sciatica with lumbar disc herniation (LDH), surgery is recommended when patients are refractory to conservative treatment\u003csup\u003e[[\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]]\u003c/sup\u003e. At present, conventional microdiscectomy (CMD) is still the standard surgical procedure for LDH\u003csup\u003e[[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]]\u003c/sup\u003e. In the past few decades, minimally invasive spine surgery (MISS) has become increasingly popular all over the world\u003csup\u003e[[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]]\u003c/sup\u003e.Percutaneous transforaminal lumbar discectomy (PTED) is one of the popular minimally invasive procedures for the treatment of lumbar disc herniation\u003csup\u003e[[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn 1987, Kambin, et al.\u003csup\u003e[[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]]\u003c/sup\u003e introduced the safe triangle (i.e., Kambin\u0026rsquo;s triangle) of percutaneous posterolateral extracanal approach for the management of LDH, reporting arthroscopic microdiscectomy in 1992\u003csup\u003e[[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]]\u003c/sup\u003e. Based on the concept of the \u0026ldquo;inside-out,\u0026rdquo; Yeung, et al.\u003csup\u003e[[\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]]\u003c/sup\u003e developed the technique of Yeung Endoscopic Spine System (YESS). Surgeons maneuvered endoscopic instruments into the intervertebral disc via the Kambin\u0026rsquo;s triangle and progressively removed the herniated disc from within. In contrast, Hoogland, et al.\u003csup\u003e[[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]]\u003c/sup\u003e, based on the concept of \u0026ldquo;outside-in,\u0026rdquo; proposed the Thomas Hoogland Endoscopic Spine System (THESSYS): inserting the working channel into the spinal canal via intervertebral foramen with plasty, excising the herniated disc from the outside to the inside, releasing and decompressing the compressed nerve root. Since then, PTED has been widely used around the world, and the results of multiple randomized controlled trials and systematic reviews\u003csup\u003e[[\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]]\u003c/sup\u003e comparing the functional and pain improvements of PTED and CMD have revealed no significant difference between the two. PTED has the advantages of less trauma, less bleeding, quick recovery, less impact on spinal stability, and operation under local anesthesia\u003csup\u003e[[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]]\u003c/sup\u003e. Gibson, et al.\u003csup\u003e[[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]]\u003c/sup\u003e and Gadjradj, et al.\u003csup\u003e[[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]]\u003c/sup\u003e have further elaborated on the PTED.\u003c/p\u003e \u003cp\u003eWith respect to PTED, safe and accurate puncture is one of the key steps for determining the difficulty of surgery and clinical outcomes\u003csup\u003e[[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]]\u003c/sup\u003e. At present, the transforaminal puncture method in PTED, nevertheless, still depends on a constant distance from the midline and estimated angles in anteroposterior and craniocaudal directions\u003csup\u003e[[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]]\u003c/sup\u003e. PTED is usually performed with the aid of intraoperative C-arm imaging. However, the C-arm does not provide sufficient information to determine the optimal depth, angle and other important parameters for safe puncture. Therefore, the surgeon needs to integrate limited information during the process of puncture, which requires high-level ability in spatial thinking, factoring in the individual experiences of the surgeon. For beginners, redo punctures are almost inevitable; unfortunately, multiple punctures necessitate increased fluoroscopy time, operation time, and radiation exposure to doctors and patients, along with the increased risk of nerve injury\u003csup\u003e[\u003c/sup\u003e[25, 26]\u003csup\u003e]\u003c/sup\u003e. One of the urgent difficulties in PTED is how to locate and puncture quickly, accurately and safely.\u003c/p\u003e \u003cp\u003eWith the three-step maneuver for puncture (TSMP) developed by the coauthors, it is possible to introduce the needle more safely and gain easy access to the herniated disc.\u003c/p\u003e "},{"header":"Methods","content":" \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eRationale and Anatomy\u003c/h2\u003e \u003cp\u003eKambin, et al.\u003csup\u003e[[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]]\u003c/sup\u003e reported a safe triangular working area (i.e., Kambin\u0026rsquo;s triangle) consisting of a two-dimensional anatomic right triangle over the lateral recess of the lumbar spine\u003csup\u003e[[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]]\u003c/sup\u003e. The triangle is bordered by the superior endplate of the lower vertebra (i.e., base of the triangle), the superior articular facet (i.e., the height of the triangle) and the exiting superior nerve root (i.e., the hypotenuse of the triangle) in a twodimensional plane (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Within this triangular area, there is no traversing nerve root or visceral structure of critical importance. Needles, guidewires and other instruments can be introduced through the described area with greater confidence in reduced incidence of complication, such as violation of the nerve root, etc.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSurgical Procedures\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003eAnesthesia and Positioning\u003c/h2\u003e \u003cp\u003eIn general, PTED is performed under local anesthesia, and, if necessary, light sedation may be administered. Under light sedation alone, a patient might be responsive. In order to facilitate the execution of TSMP, the patient will be placed in a prone position on the radiolucent table. With respect to the lateral position, there may be many advantages, such as a larger safety zone with respect to the dura, less bleeding, and so on\u003csup\u003e[[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]]\u003c/sup\u003e. Another advantage of the prone position is that the position of patients is more stable, allowing less movement. Further, surgeons are quite familiar with the anatomy and its landmarks in this position.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003eTarget and entry point\u003c/h2\u003e \u003cp\u003eUsing the mobile C-arm for anteroposterior and lateral radiographic control, the target and the entry point will be accurately positioned for operators. The target is located at the intersection of the superior endplate line of the lower vertebra and the inner line of lower vertebral pedicle in anteroposterior projection (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA), or at the intersection of the trailing line of the lower vertebral body and the superior endplate line of the lower vertebra in lateral projection (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB). The area of needle insertion is located on the patient\u0026rsquo;s posterolateral side, which is an approximating rectangle (AR) formed by the line of spinous process, the line of transverse process, the superior endplate line of the upper vertebra and the superior endplate line of the lower vertebra in lateral projection (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). During the operation, the appropriate entry point should be determined in the AR according to the location of the herniated disc: (1) The closer the position of the disc is to the center, the closer the needle point is to the ventral side; (2) The closer the position of the disc is to the cephalad side, the closer the needle point is to the caudal side. The line connecting the entry point to the target is the surgical approach (SA).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section4\"\u003e \u003ch2\u003eTSMP\u003c/h2\u003e \u003cp\u003eAfter layer-by-layer local infiltration of anesthetic to the skin of the entry point with 1% lidocaine, an 18-gauge spinal needle will be inserted. Components of the TSMP are as follows:\u003c/p\u003e \u003cp\u003eStep 1: The needle is inserted through the appropriate entry point and advanced toward the spinous process by inches. The approach of puncture is parallel to the projected line of the SA on the back bed. When the needle tip reaches the bony structure (i.e., spinous process), the location of the tip will be determined by using biplanar C-arm images. The process is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eStep 2: The needle is pulled out an appropriate distance (about 3 to 5\u0026nbsp;cm). Then, after raising the needle tail properly, the needle will be advanced toward the superior articular facet. When the needle tip reaches the bony structure (i.e., superior articular facet), the location of the tip will be determined by using biplanar C-arm images. The process is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB.\u003c/p\u003e \u003cp\u003eStep 3: The needle is pulled out an appropriate distance again (about 2 to 3\u0026nbsp;cm). Then, after raising the needle tail properly, the needle will be advanced toward the target, and the surgeon will feel the needle tip slide into the intervertebral foramen along the superior articular facet. When the needle tip reaches the bony structure (i.e., target), the location of the tip will be determined by using biplanar C-arm images. The process is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003eForaminoplasty, placing of the working channel and introducing the endoscope\u003c/h2\u003e \u003cp\u003eThe typical surgical procedures, including foraminoplasty, introduction of the working channel and endoscope, removal of the target disc and decompression of the nerve, continue, consistent with conventional techniques of PTED\u003csup\u003e[[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]]\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eClinical Materials and Statistical Analysis\u003c/h2\u003e \u003cp\u003eWe performed a retrospective review of 30 patients who underwent PTED using TSMP for LDH from January 2018 to September 2018. The inclusion criteria were as follows: (1) age 18 to 70 years; (2) single-level surgery; (3) informed consent; and (4) at least one year after surgery. Exclusion criteria consisted of: (1) previous surgery on the same or adjacent disc level; (2) spondylytic or degenerative spondylolisthesis; (3) severe somatic or psychiatric illness; and (4) history of psychiatric or psychological disorder. The primary outcome, leg or back pain, was assessed using the Visual Analogue Scale (VAS)\u003csup\u003e[[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]]\u003c/sup\u003e. Surgical satisfaction was measured using a five-point Likert scale\u003csup\u003e[[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]]\u003c/sup\u003e, varying from \u0026ldquo;very satisfied\u0026rdquo; (5 points) to \u0026ldquo;very unsatisfied\u0026rdquo; (1 point). The following potential prognostic factors were measured: (1) demographic characteristics (e.g., age and gender); (2) duration of symptom (DOS); (3) involved levels. Statistical analysis was performed using Fisher exact test and t-test, and the P value\u0026thinsp;\u0026lt;\u0026thinsp;.05 was regarded as statistically significant. Ethical approval has been granted by the Ethics Committee of Fujian Medical University Union Hospital, Fuzhou, China (2018YF010-02).\u003c/p\u003e \u003c/div\u003e "},{"header":"Results","content":" \u003cp\u003eThere were 30 patients with LDH who met the inclusion criteria and had undergone PTED using TSMP. The demographic findings are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The followup time was 1\u0026nbsp;year. The preoperative mean VAS was 7.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.19, which decreased to 1.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97\u0026nbsp;at 12\u0026nbsp;months following treatment (P\u0026thinsp;\u0026lt;\u0026thinsp;\u0026minus;\u0026thinsp;.0001). Based on a five-point Likert scale, the rates of surgical satisfaction were as follows: very satisfied and satisfied in 26 patients (86.7%), general in three patients (13.3%). Three recurrent disc herniations of adjacent segmental levels were observed in the L5-S1 group at eight and 12\u0026nbsp;months after surgery. One of the patients with recurrence underwent tubular microdiscectomy at 12\u0026nbsp;months after undergoing PTED using TSMP. According to the subgroup analysis, there were significantly different VAS scores at 12\u0026nbsp;months postoperatively between the L4-L5 group and the L5-S1 group (P\u0026thinsp;\u0026lt;\u0026thinsp;.01). There were no significant influences at 12\u0026nbsp;months after PTED on the primary outcome from other factors, including gender, age, body mass index (BMI), and DOS (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cdiv class=\"SimplePara\"\u003eDemographic Characteristics\u003c/div\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003eData\u003c/div\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003eNo.\u003c/div\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003ePercent\u003c/div\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eGender\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eMale\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e17\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e56.70%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eFemale\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e13\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e43.30%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eAge\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e\u0026le;\u0026thinsp;40 yrs\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e8\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e26.70%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e༞40 yrs\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e22\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e73.30%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eBMI (kg/m\u003c/span\u003e\u003csup\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e2\u003c/span\u003e\u003c/sup\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e)\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e\u0026le;\u0026thinsp;23\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e12\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e40%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e༞23\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e18\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e60%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eSide\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eRight\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e9\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e30%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eLeft\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e21\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e70%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eDuration of symptoms\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e\u0026le;\u0026thinsp;6 months\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e18\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e60%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e༞6 months\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e12\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e40%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eLevel\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eL4/5\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e14\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e46.70%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eL5/S1\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e16\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e53.30%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eLocation\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eCentral\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e11\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e36.70%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eLateral\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e7\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e23.30%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eForaminal\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e12\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e40%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e5-Point Likert scale (12 months following treatment)\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e༞3\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e26\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e86.7%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e\u0026le;\u0026thinsp;3\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003e4\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003e13.3%\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cdiv class=\"SimplePara\"\u003ePrimary Outcome and Clinical Factors\u003c/div\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003eVariable\u003c/div\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003eMeans\u0026thinsp;\u0026plusmn;\u0026thinsp;Standard deviation(SD)\u003c/div\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003eSample\u003c/div\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cdiv class=\"SimplePara\"\u003eP value\u003c/div\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cdiv class=\"SimplePara\"\u003eConfidence interval(CI)\u003c/div\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eVisual Analogue Scale (VAS)\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003ePreoperative\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e7.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.19\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e30\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e[5.60, 6.73]\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003e12 Months\u003c/span\u003e\u003c/div\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003efollowing treatment\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e30\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eClinical factors affecting VAS (at 12 months following treatment)\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eAge\u0026thinsp;\u0026le;\u0026thinsp;40 yrs\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.64\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e8\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u0026gt;\u0026thinsp;0.20\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e[-1.09, 0.24]\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eAge ༞40 yrs\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.55\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e22\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eMale\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.79\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e17\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u0026gt;\u0026thinsp;0.60\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e[-0.99, 0.61]\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eFemale\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.54\u0026thinsp;\u0026plusmn;\u0026thinsp;1.20\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e13\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eBMI* \u0026le;23\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e12\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u0026gt;\u0026thinsp;0.10\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e[-0.21, 1.27]\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eBMI ༞23\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e18\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eDOS* \u0026le;6 months\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.98\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e18\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u0026gt;\u0026thinsp;0.20\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e[-0.29, 1.18]\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eDOS ༞6 months\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e12\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eL4/5\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e0.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.62\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e14\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.01\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cdiv class=\"SimplePara\"\u003e[-1.59, -0.30]\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Italic\" class=\"Italic\" name=\"Emphasis\"\u003eL5/S1\u003c/span\u003e\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cdiv class=\"SimplePara\"\u003e1.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.02\u003c/div\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cdiv class=\"SimplePara\"\u003e16\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cdiv class=\"SimplePara\"\u003e*BMI, Body Mass Index; DOS, duration of symptoms\u003c/div\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e "},{"header":"Discussion","content":" \u003cp\u003eAccurate location for puncture is an essential step in most spinal surgery and is especially important to PTED. As for the conventional procedures of PTED, transforaminal puncture still depends on a constant distance from the midline and the estimated angles in anteroposterior and craniocaudal orientations\u003csup\u003e[[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]]\u003c/sup\u003e. It is complicated and difficult for beginners to insert a needle into the intervertebral foramen relying on the traditional method. Therefore, the learning curve for PTED is often described as steep\u003csup\u003e[[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]]\u003c/sup\u003e. Accurate needle puncture and trajectory is essential to safe, successful surgery. If the puncture were inaccurate, increased puncture frequency and increased fluoroscopy time would be inevitable, thus increasing radiation exposure to doctors and patients. Notably, radiation exposure has been found to increase the risk of some types of cancer for exposed surgeons\u003csup\u003e[[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]]\u003c/sup\u003e. Han, et al.\u003csup\u003e[[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]]\u003c/sup\u003e developed the obturator guiding technique in order to enhance safety and reduce drawbacks associated with the needle insertion process. The traditional technique, nevertheless, still depends on the previously described distance and angles. In 2015, Fan, et al.\u003csup\u003e[[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]]\u003c/sup\u003e designed and produced the He\u0026rsquo;s lumbar location system (HELLO), which could improve puncture accuracy and reduce fluoroscopy time in the performance of PTED. However, the surgeon is required to repeatedly adjust the positioner and the C-arm for fluoroscopy, which amounts to extra time-consuming steps. Their system has not really been popular all over the world. Therefore, based on the anatomy of spine, this article introduced a simple and more accessible three-step maneuver for puncture (TSMP) in PTED.\u003c/p\u003e \u003cp\u003eTSMP is a three-step maneuver that builds on the concept of needle puncture site and trajectory determination based on the principles of Kambin\u0026rsquo;s triangle. First, accurate direction of the puncture is confirmed by inserting the needle horizontally. Then by gradually raising the needle tail in the manner described, the superior articular facet and the intervertebral foramen are sequentially located. Finally, the needle tip slides into the intervertebral foramen to reach the target superior articular facet. In this study, we performed a retrospective review on patients who underwent PTED using TSMP for LDH. Patients\u0026rsquo; sciatica was significantly relieved at 12 months after PTED using TSMP. By subgroup analysis, there were better VAS scores about 12 months postoperatively in the L4-L5 group compared to the L5-S1 group (P\u0026thinsp;\u0026lt;\u0026thinsp;.01). The reason for this result may be that PTED performed in L5-S1 group was more easily influenced by iliac crest. For patients with the L5/S1 disc herniation, especially in case of high iliac crest, there are differences in the operation due to the anatomical obstruction: 1) require a more medial placement of the entry point; 2) a resection of the lateral one fourth of the facet joint\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eTSMP relies on the natural anatomy of the individual patient to progressively deliver the needle to the target. For this reason, TSMP could prove to be a more stable surgical technique compared than the traditional puncture method. However, there are several limitations in our study: (1) The appropriate entry point should be determined in the AR according to the location of the herniated disc, but operators cannot locate the most accurate entry point through TSMP at present. (2) Pragmatic, precise and prospective RCT, with sufficient samples and long-term followup, comparing PTED using TSMP to conventional microdiscectomy, was not performed. Hence, comparing with other procedures, the efficacy and safety of PTED using TSMP need to be further evaluated.\u003c/p\u003e "},{"header":"Conclusions","content":" \u003cp\u003eTSMP is a stable surgical technique for inserting the needle into the intervertebral foramen. Patients who underwent PTED using TSMP fared significantly better with regard to leg and back pain at 12 months after surgery. Given these potential advantages, more research is needed to confirm the efficacy and safety of PTED using TSMP.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eABBREVIATIONS: \u003c/strong\u003e\u003cstrong\u003eLDH\u003c/strong\u003e, lumbar disc herniation; \u003cstrong\u003eCMD\u003c/strong\u003e, conventional microdiscectomy; \u003cstrong\u003eMISS\u003c/strong\u003e, minimally invasive spine surgery; \u003cstrong\u003ePTED\u003c/strong\u003e, percutaneous transforaminal endoscopic discectomy; \u003cstrong\u003eYESS\u003c/strong\u003e, Yeung Endoscopic Spine System; \u003cstrong\u003eTHESSYS\u003c/strong\u003e, Thomas Hoogland Endoscopic Spine System; \u003cstrong\u003eTSMP\u003c/strong\u003e, three-step maneuver for puncture; \u003cstrong\u003eAR\u003c/strong\u003e, approximating rectangle; \u003cstrong\u003eSA\u003c/strong\u003e, surgical approach; \u003cstrong\u003eVAS\u003c/strong\u003e, Visual Analogue Scale; \u003cstrong\u003eDOS\u003c/strong\u003e, duration of symptom\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e This study has been granted by the Ethics Committee of Fujian Medical University Union Hospital, Fuzhou, China (2018YF010-02).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication: \u003c/strong\u003eYes\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials: \u003c/strong\u003eThrough the email(\u003ca href=\"mailto:[email protected]\"\[email protected]\u003c/a\u003e) to contact us for accessing data.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e none\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding: \u003c/strong\u003eThis work was funded by Technology and Innovation Foundation of Fujian, China (grant no 2018Y9060 to CM)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions: \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConception or design of the work: Chun Mei Chen\u003c/p\u003e\n\u003cp\u003eAcquisition of data: Shao Xiong Chen\u003cbr /\u003e Analysis of data: Shao Xiong Chen\u003cbr /\u003e Interpretation of data: Ze Yan Liang\u003cbr /\u003e Drafting the work: Ze Yan Liang\u003c/p\u003e\n\u003cp\u003eRevising the work for valuable intellectual content: Rui Wang\u003cbr /\u003e Final approval of the version: Chun Mei Chen\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u003c/strong\u003e none\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKonstantinou K, Dunn K: \u003cstrong\u003eSciatica: review of epidemiological studies and prevalence estimates\u003c/strong\u003e. \u003cem\u003eSpine \u003c/em\u003e2008, \u003cstrong\u003e33\u003c/strong\u003e(22):2464-2472.\u003c/li\u003e\n\u003cli\u003eJacobs WC, Arts MP, van Tulder MW, Rubinstein SM, van Middelkoop M, Ostelo RW, Verhagen AP, Koes BW, Peul WC: 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The transforaminal puncture method currently employed in PTED depends on a constant distance from the midline and estimated angles in anteroposterior and craniocaudal directions. TSMP is an alternative concept of puncture based on Kambin’s triangle. TSMP references the natural anatomy of patients to progressively advance the needle to target. We herein discribed a three-step maneuver for puncture (TSMP) in PTED, which is possible to introduce the needle more safely and gain easy access to the herniated disc.\u003c/p\u003e\u003cp\u003eMethods: We performed a retrospective review of 30 patients who underwent PTED using TSMP for lumbar disc herniation (LDH) and met inclusion criteria from January 2018 to September 2018. The primary outcome, leg or back pain, was assessed using Visual Analogue Scale (VAS). Patient surgical satisfaction was measured at 12 months post surgery using a five-point Likert scale. Potential prognostic factors measured were demographic characteristics, duration of symptom (DOS), and involved levels. Statistical analysis was performed using Fisher exact test and t-test..\u003c/p\u003e\u003cp\u003eResults: Preoperative mean VAS was 7.6 ± 1.19, which decreased to 1.4 ± 0.97 at12 months following treatment (P \u0026lt; .0001). Rates of surgical satisfaction per Likert scale were as follows: very satisfied and satisfied in 26 patients (86.7%). VAS scores at 12 months varied significantly between L4-L5 level surgery and L5-S1 level surgery groups (P \u0026lt; .01).\u003c/p\u003e\u003cp\u003eConclusion: TSMP is a reliable technique for puncture into the intervertebral foramen.\u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Technical Tips for Percutaneous Transforaminal Endoscopic Discectomy: a three-step maneuver for puncture and early clinical experience","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2020-03-26 15:36:59","doi":"10.21203/rs.3.rs-18310/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"157c6221-0f8a-4db2-8f39-1eb413e4d18c","owner":[],"postedDate":"March 26th, 2020","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":75017,"name":"Orthopedics"}],"tags":[],"updatedAt":"2020-07-31T14:13:41+00:00","versionOfRecord":[],"versionCreatedAt":"2020-03-26 15:36:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-18310","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-18310","identity":"rs-18310","version":["v1"]},"buildId":"-HB7Z8yhvgn0wM9Nzuekk","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}