Transforaminal Percutaneous Endoscopic Lumbar Discectomy Research Articles

Retrospective Study of Minimal Three-Year Follow-Up of Transforaminal Endoscopic Discectomy for Lumbar Disc Herniation: 5000 Multicenter Cases.

Objective The objective of this study was to investigate the long-term effects of percutaneous transforaminal endoscopic lumbar discectomy (PTELD) and clarify the differences between outside-in and inside-out techniques. Methodology This was a multicenter retrospective study with a chart review of questionnaires about patients' quality of life. Patients were recruited from three hospitals in China. Based on certain inclusion and exclusion criteria, we enrolled in the study 5000 patients aged ≥18 years diagnosed with lumbar disc herniation who received PTELD from September 2015 to September 2019. The outside-in technique (n=2039) was compared with the inside-out technique for PTELD (n=1890) on the Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and the Short Form 36 (SF-36) of the Health Survey Questionnaire (physical component)both pre-operatively and post-operatively. Results VAS, ODI, andSF-36 significantly improved just after surgery for both techniques compared with pre-operative status. Nevertheless, significant differences existed between the two techniques concerning VAS for leg pain, VAS for back pain, ODI, and SF-36 at 0.5 monthspost-operatively. The above indices steadily improved within six months after both techniques, after which they did not significantly improve. In detail, outside-in patients suffered more back pain and worse ODI and SF-36 (physical) but had more relief from leg pain 0.5 months after surgery in terms of VAS. As for recovery rate from symptoms, there were only significant differences in recovery rate for leg pain and back pain at the first 1.5 months post-operatively. As for satisfaction rates, the outside-in technique had better results than the inside-out technique at both 0.5 months and 12 months. Conclusion Both techniques could relieve the symptoms of lumbar disc herniation. However, patients in the outside-in group suffered more back pain and a bigger risk of nerve injury than those in the inside-out group.

Spectrum of organism in Post-Operative Spondylodiscitis following Percutaneous Transforaminal Endoscopic Lumbar Discectomy: A series of 19 patients.

Spectrum of organism in Post-Operative Spondylodiscitis following Percutaneous Transforaminal Endoscopic Lumbar Discectomy: A series of 19 patients.

Coaxial radiography guided puncture technique for percutaneous transforaminal endoscopic lumbar discectomy: A randomized control trial.

The coaxial radiography-guided puncture technique (CR-PT) is a novel technique for endoscopic lumbar discectomy. As the X-ray beam and the puncturing needle are maintained in a parallel and coaxial direction, the X-ray beam can be used to guide the trajectory angle, facilitating the choice of the puncture site and providing real-time guidance. This puncture technique offers numerous advantages over the conventional anterior-posterior and lateral radiography-guided puncture technique (AP-PT), especially in cases of herniated lumbar discs with a hypertrophied transverse process or articular process, high iliac crest, and narrowed intervertebral foramen. To confirm whether CR-PT is a superior approach to percutaneous transforaminal endoscopic lumbar discectomy compared to AP-PT. In this parallel, controlled, randomized clinical trial, herniated lumbar disc patients appointed to receive percutaneous endoscopic lumbar discectomy treatment were recruited from the Pain Management Department of the Affiliated Hospital of Xuzhou Medical University and Nantong Hospital of Traditional Chinese Medicine. Sixty-five participants were enrolled and divided into either a CR-PT group or an AP-PT group. The CR-PT group underwent CR-PT, and the AP-PT group underwent AP-PT. The number of fluoroscopies during puncturing, puncture duration (min), surgery duration (min), VAS score during puncturing, and puncture success rate were recorded. Sixty-five participants were included, with 31 participants in the CR-PT group and 34 in the AP-PT group. One participant in the AP-PT group dropped out due to unsuccessful puncturing. The number of fluoroscopies [median (P25, P75)] was 12 (11, 14) in the CR-PT group vs 16 (12, 23) in the AP-PT group, while the puncture duration (mean ± SD) was 20.42 ± 5.78 vs 25.06 ± 5.46, respectively. The VAS score was 3 (2, 4) in the CR-PT group vs 3 (3, 4) in the AP-PT group. Further subgroup analysis was performed, considering only the participants with L5/S1 segment herniation: 9 patients underwent CR-PT, and 9 underwent AP-PT. The number of fluoroscopies was 11.56 ± 0.88 vs 25.22 ± 5.33; the puncture duration was 13.89 ± 1.45 vs 28.89 ± 3.76; the surgery duration was 105 (99.5, 120) vs 149 (125, 157.5); and the VAS score was 2.11 ± 0.93 vs 3.89 ± 0.6, respectively. All the above outcomes demonstrated statistical significance (P < 0.05), favoring the CR-PT treatment. CR-PT is a novel and effective technique. As opposed to conventional AP-PT, this technique significantly improves puncture accuracy, shortens puncture time and operation time, and reduces pain intensity during puncturing.

Angulation error assessment for the trajectory in the anteroposterior and lateral fluoroscopic views during percutaneous endoscopic transforaminal lumbar discectomy

BackgroundAnteroposterior (AP) and lateral fluoroscopies are often used to evaluate the intraoperative location and angulation of the trajectory in percutaneous endoscopic transforaminal lumbar discectomy (PETLD). Although the location of the trajectory shown in fluoroscopy is absolutely accurate, the angulation is not always reliable. This study aimed to evaluate the accuracy of the angle shown in the AP and lateral fluoroscopic views.MethodsA technical study was performed to assess the angulation errors of PETLD trajectories shown in AP and lateral fluoroscopic views. After reconstructing a lumbar CT image, a virtual trajectory was placed into the intervertebral foramen with gradient-changing coronal angulations of the cephalad angle plane (CACAP). For each angulation, virtual AP and lateral fluoroscopies were taken, and the cephalad angles (CA) of the trajectory shown in the AP and lateral fluoroscopic views, which indicated the coronal CA and the sagittal CA, respectively, were measured. The angular relationships among the real CA, CACAP, coronal CA, and sagittal CA were further demonstrated with formulae.ResultsIn PETLD, the coronal CA is approximately equal to the real CA, with a small angle difference and percentage error, whereas the sagittal CA shows a rather large angle difference and percentage error.ConclusionThe AP view is more reliable than the lateral view in determining the CA of the PETLD trajectory.

Prodrome to Seizure in Transforaminal Endoscopic Surgery: A Series of 9 Cases

Objective: Percutaneous transforaminal endoscopic lumbar discectomy (PTELD) is safe and ef- fective. Perioperative or postoperative seizures are a rare complication that can be prevented by promptly identifying prodromal symptoms and signs. This study aimed to identify prodromal symptoms and risk factors of avoidable seizures in patients undergoing PTELD and to quantify irrigation fluid ingression into the epidural space on immediate postoperative magnetic reso- nance imaging (MRI).Methods: This retrospective analysis included patients who underwent PTELD under local anes- thesia from February 2018 to June 2022. Surgical records were reviewed to identify patients who developed prodromal symptoms, and immediate postoperative MRI was evaluated for ra- diological correlations.Results: Nine patients developed prodromal symptoms of neck pain (n = 6), upper dorsal pain (n = 7), headache (n = 2), confusion (n = 2), visual disturbance (n = 1) and hemodynamic alter- ations (n = 4). No patients had seizures. Calcified lumbar disc herniation-associated posterior apophyseal ring fracture, central lumbar disc herniation, obesity, double-level surgery, use of an automated pump, and a large working channel endoscope were associated with an increased fluid flow rate for epidural work and duration of surgery. MRI showed significant epidural fluid collection cranial to the operative level, reaching the thoracolumbar junction, in patients with prodrome, suggesting increased intracranial pressure due to thecal sac compression. Conclusion: Prodromal symptoms should be considered a red flag for avoidable seizures. The duration of surgery and infusion fluid flow rate are controllable risk factors during surgery. Risk factors should be kept in mind. The judicious use of automated pumps and larger channel work- ing endoscopes is recommended.

Application of a new body surface-assisting puncture device in percutaneous transforaminal endoscopic lumbar discectomy

BackgroundAccurate puncture and localization are critical for percutaneous transforaminal endoscopic lumbar discectomy surgery. However, several punctures are often required, followed by X-ray fluoroscopy, which can increase surgical risk and complications. The aim of this study was to demonstrate a new body surface-assisting puncture device that can be used in percutaneous transforaminal endoscopic lumbar discectomy and to assess its clinical effectiveness.MethodsThree hundred and forty-four patients were treated with percutaneous transforaminal endoscopic lumbar discectomy surgery in the Spinal Surgery Department of Taian City Central Hospital, China, between January 2020 and February 2022. Of these, 162 patients (the locator group) were punctured using a body surface-assisting puncture device while and 182 patients (the control group) were punctured using the traditional blind puncture method. The number of punctures, radiation dose during X-ray fluoroscopy, operation time, and surgical complications were compared between the two groups.ResultsThe average number of punctures was 2.15 ± 1.10 in the locator group which was significantly lower than that in the control group (5.30 ± 1.74; P < 0.001). The average X-ray fluoroscopy radiation dose in the locator group was significantly lower at 2.34 ± 0.99 mGy, compared with 5.13 ± 1.29 mGy in the control group (P < 0.001). The mean operation time was also significantly less in locator group (47.06 ± 5.12 vs. 62.47 ± 5.44 min; P = 0.008). No significant differences in surgical complications were found between the two groups (P > 0.05).ConclusionThe use of a new body surface-assisting puncture device in percutaneous transforaminal endoscopic lumbar discectomy surgery can significantly reduce the number of punctures and X-ray fluoroscopy radiation dose, as well as shortening the operation time, without increasing surgical complications. This device is cheap, easy to operate, and suitable for all hospitals and spine surgeons, especially for small hospitals, with also no extra costs for patients.

A one-step foraminoplasty via a large trephine in percutaneous endoscopic transforaminal discectomy for the treatment of lumbar disc herniation.

Transforaminal percutaneous endoscopic lumbar discectomy (PELD) is a widely used basic technique for lumbar disc herniation (LDH) with advantages including causing less trauma and fast recovery. The secure, efficient, and rapid enlargement of the intervertebral foramen is a key step in PELD procedures. However, the conventional multi-step trephine system for foraminoplasty involves complicated surgical procedures. In this study, we reported an improved one-step foraminoplasty via a large trephine with simplified surgical procedures, reduced radiation exposure, and shortened operative time. 70 LDH patients who underwent PELD were retrospectively reviewed in this study. The conventional multi-step trephine system was used for foraminoplasty in 35 patients in the multi-step (MS) group, and the single large trephine was used in the other 35 patients in the one-step (OS) group. Indicators including the operative time, the time to establish the working cannula, intraoperative fluoroscopy times, the radiation dose, and postoperative complications were compared between the MS and OS group. The operative time and the time to establish the working cannula in the OS group was significantly shorter than that in the MS group (P < 0.01); intraoperative fluoroscopy times and the radiation dose in the OS group were significantly smaller than those in the MS group (P < 0.01). There was no statistical difference in the incidence of postoperative complications between the two groups (P > 0.05). The postoperative VAS scores and ODI scores (2 days and 3 months after the surgery) were significantly lower than the preoperative scores in both groups (P < 0.01), and there was no statistical difference in VAS scores or ODI scores between the two groups at the same time points (P > 0.05). The one-step foraminoplasty via a single large trephine is an optimized technique evolving from the conventional multi-step foraminoplasty, showing significant superiority in simplified operation, shorted operative time, and reduced radiation exposure.

Clinical Outcomes of Transforaminal Percutaneous Endoscopic Lumbar Discectomy in Malaysia

Clinical Outcomes of Transforaminal Percutaneous Endoscopic Lumbar Discectomy in Malaysia

Transforaminal Percutaneous Endoscopic Lumbar Discectomy (TPELD) in Caudal Migrated Lumbar Disc Herniations: A Case Series and Literature Review

Background Data: Since the initial idea by Kambin and Gellman in 1973 of percutaneous posterolateral lumbar disc decompression, the evolution of minimally invasive interventions in disc herniation has been widely growing. The advancements in optics and surgical instruments allowed surgeons to perform true minimally invasive procedures in a wide range of spine pathologies. In addition, transforaminal percutaneous endoscopic lumbar discectomy (TPELD) has been widely utilized in various degenerative spine pathologies, due to the presence of high-speed drills, flexible forceps, scissors, curettes, and probes to manage pathologies such as disc herniation or canal stenosis.

Functional outcome of back pain after percutaneous endoscopic lumbar discectomy and annuloplasty for lumbar disc herniation: A prospective study

Objective: Percutaneous Transforaminal endoscopic lumbar discectomy and annuloplasty (PELDA) is a minimally invasive spinal technique for lumbar disc herniation. Following discectomy, the relief of leg pain is common; however, the relief of back pain is less predictable. The purpose of this study was to evaluate changes in back pain and to examine the predisposing factors for postoperative back pain following PELDA. Material and Method: In this prospective study, 104 patients with leg and back pain associated with disc herniation underwent PELDA. The patients were divided into two groups: unfavorable and favorable. Patients were defined as having unfavorable outcomes if the percentage improvement of back pain 20% at postoperative 12 months. The preoperative demo-graphic, clinical, and radiologic factors for each group were statistically analyzed. Results: 104 patients were enrolled in this study. The mean visual analog scale scores for back pain and the ODI scores significantly improved from 6.6 and 55.9% preoperatively to 2.5 and 12.7% at the 12 month follow-up. The surgical satisfaction rate was 78.4% at the final follow-up. Eighteen (34.6%) patients had unfavorable outcomes. Patients with advanced disc degeneration of operative levels had significantly worse outcomes than those with mild disc degeneration (odds ratio: 6.316, 95% confidence interval 1.25–31.86, P

A comparative study of conventional microlumbar discectomy and endoscopic lumbar discectomies

Background: Low back pain is fairly common in India and lumbar disc herniation is its most common specific cause. In the present study we compared three minimally invasive surgical modalities for treating lumbar disc herniation.Methods: This prospective observational study was conducted on patients who presented to our department with low back pain with radicular symptoms. Twenty-five patients who underwent either microlumbar disectomy (MLD), percutaneous endoscopic transforaminal lumbar discectomy (PELD) or microendoscopic lumbar discectomies (MED) were compared.Results: Of the total sample of 75 cases, it was found that male population was affected more and the degenerative disc process was more prevalent among those over 40 years of age. The MED had the shortest operative time while MLD had the longest mean duration. A comparison of the intraoperative blood loss was negligible in PELD group and 42.80 ml in MED and 63.20 ml in MLD which was strongly significant with a p&lt;0.001. Pain scores were comparable between the patients in the three surgery groups. We observed significantly higher ODI score for patients in MLD group at in the immediate post-operative, 3 months and 6 months post-operative period.Conclusions: MLD is the gold standard for treatment for lumbar disc disease even today due to its familiarity among neurosurgeons; however, reduced tissue destruction and cosmetic demand with equally good results if not better, endoscopy could replace MLD as the first-line treatment for LDH until lesser invasive modality comes to light.

Percutaneous Transforaminal Endoscopic Lumbar Discectomy in Adolescents

Abstract Background: Lumbar disc herniation in adolescents is relatively rare but poses a serious problem to the patient and the parents. Percutaneous Transforaminal Endoscopic Lumbar Discectomy (PTELD) has several advantages over conventional surgeries because it decreases perioperative complications and increases favorable clinical outcomes. Aim of Study: The aim of this study is to evaluate the clinical outcomes of PTELD in adolescent patients. Patients and Methods: Adolecence is defined as any person whose age is between 10 and 19 years. This was a retrospective study which included 14 patients aged between 15 and 19 years treated by PTELD for low back pain and sciatica. Clinical and functional outcomes were evaluated using visual analogue scale (VAS), Oswestry Disability Index (ODI) and follow-up at 2 weeks, 1, 2, 6 and 12 months postoperatively. Final results were assessed using the modified MacNab score. All surgeries were done by the same surgeon. Results: Overall there was improvement of clinical and functional outcomes during the postoperative follow-up eval-uation. There were no immediate perioperative complications, such as infection, nerve injury or dural tears but only two patients developed dysathesia and were treated medically. There was no recurrence of herniations as the patients followed a strict postoperative rehabilitation program. Conclusion: PTELD is a minimally invasive technique which is effective and safe for adolescent patients. PTELD decreases the post-operative morbidity and permits faster mobility and rehabilitation.

Transforaminal Percutaneous Endoscopic Lumbar Discectomy Through a Transfacet Approach: Detailed Surgical Technique

Journal of Minimally Invasive Spine Surgery & Technique (JMISST) is the official journal of the Korean Minimally Invasive Spine Surgery Society (KOMISS) for the publication of research results about minimally invasive spinal surgery (MISS), including studies in spinal endoscopic surgery, minimally invasive procedure for degenerative spine disease, pain intervention, and minimally invasive surgery for spinal fusion or spine trauma, neuroscience, neurology, molecular biology and biomechanics etc. Articles with helpful information for MISS such as reports of rare cases or technical review of special devices or equipment are also available

Clinical Outcomes of "U" Route Transforaminal Percutaneous Endoscopic Lumbar Discectomy in Chronic Pain Patients with Lumbar Spinal Stenosis Combined with Disc Herniation.

Introduction “U” route transforaminal percutaneous endoscopic lumbar discectomy (PELD) was introduced for lumbar spinal stenosis (LSS) combined with disc herniation (DH) treatment. This study aims to explore the efficacy and safety of “U” route PELD on chronic pain patients with LSS combined with DH. Methods Degenerative LSS combined with DH patients who underwent “U” route PELD were reexamined, and 80 patients were recruited and followed up for 2 years. The other 80 healthy individuals who were age- and sex-matched to the patients without chronic pain were enrolled as healthy controls. Minimum dura sac cross-sectional area (mDCSA) by MRI, Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and modified MacNab outcomes were assessed. Emotional evaluation of pain catastrophizing and depression was documented with Pain Catastrophizing Scale (PCS) and Beck Depression Inventory (BDI), respectively, for patients before and after surgery and healthy individuals. Results All patients were of the age range from 47 to 85 years, with an average of 59.5 ± 9.76 years. Symptoms duration was 114.6 ± 22.77 months, operation time was 87.7 ± 25.20 minutes, and the average hospital stay was 5.8 ± 2.81 days. Four patients quit, and hence, a total of 76 patients completed the follow-up. The results indicated that mDCSA was improved significantly after operation (p < 0.001), either low back and leg VAS or ODI decreased over time (p < 0.001), and the excellent-to-good rate was improved from 88.75% to 93.42% during postoperative 2 years (p < 0.05). Complications of dural tear, nerve root, or dysesthesia were reported in 5 patients, and all recovered after conservative therapy. The scores of pain catastrophizing were reduced after operation (p < 0.001), but no significance of BDI was found between patients and healthy controls (p > 0.05). Conclusions The “U” route PELD seems an alternative to LSS combined with DH treatment, which might reach a better decompression and effectively improve chronic pain conditions. Still, the complications were potential and required further consideration.

The Trans-Superior Articular Process Approach Utilizing Visual Trephine: A More Time-Saving and Effective Percutaneous Endoscopic Transforaminal Lumbar Discectomy for Migrated Lumbar Disc Herniation.

To introduce, and to evaluate the efficacy of the trans-superior articular process (trans-SAP) approach utilizing visual trephine in percutaneous endoscopic transforaminal lumbar discectomy (PETLD) for migrated lumbar disc herniation. This study included 98 patients, 50 patients were in trans-SAP PETLD group and 48 patients were in conventional PETLD group. Visual analogue scale (VAS), Oswestry disability index (ODI), gender, age, blood loss, operation time, the frequency of X-ray fluoroscopy and the percentage of highly migrated herniation were evaluated and compared between the trans-SAP PETLD and conventional PETLD group. In both trans-SAP PETLD and conventional PETLD group, VAS and ODI were decreased at postoperative 1 day and 3 months compared with preoperative (p < 0.001). What's more, the VAS and ODI of postoperative 3 months were lower than postoperative 1 day (p < 0.001). There was no difference in gender, age, blood loss after the operation, and VAS during operation between trans-SAP group and conventional group (p > 0.05). The blood loss during the operation of trans-SAP group was higher (p < 0.05), but the operation time and frequency of X-ray fluoroscopy were lower than conventional group (p < 0.001). Last, trans-SAP group had a higher percentage of highly migrated herniation (p < 0.001). Both the conventional way and trans-SAP approach can achieve excellent surgical results. But, in trans-SAP group, the operation time is shorter, and X-ray fluoroscopy is less. PETLD with visual trephine has more advantages in highly migrated herniation and maybe easier to be mastered by young surgeons.

Analysis of Influencing Factors on Short-Term Efficacy of Percutaneous Transforaminal Endoscopic Lumbar Discectomy in the Treatment of Lumbar Disc Herniation

To explore the factors influencing the short-term efficacy of percutaneous transforaminal endoscopic lumbar discectomy in the treatment of lumbar disc herniation is the main objective. 100 patients with lumbar disc herniation who were treated in our hospital from February 2017 to February 2019 were selected as the control group (n=85, effective) and observation group (n=15, ineffective), the effective rate of treatment was statistically analyzed. Visual analogue scale and Japanese orthopaedic association scores were compared before surgery, 3 mo after surgery and 6 mo after surgery. The influencing factors of lumbar disc herniation treatment effect were analyzed. The effective rate of lumbar disc herniation patients treated by percutaneous transforaminal endoscopic lumbar discectomy surgery was 85.00 %. Compared with that before surgery, the visual analogue scale score of lumbar disc herniation patients was significantly decreased 3 mo after surgery and 6 mo after surgery, but the Japanese orthopaedic association score was significantly increased (p<0.05). In logistics regression analysis, it was found that the course of disease, history of trauma and degree of lumbago were the main factors affecting the therapeutic efficacy of percutaneous transforaminal endoscopic surgery in patients with lumbar disc herniation. There are many factors influencing the efficacy of percutaneous transforaminal endoscopic surgery for lumbar disc herniation patients and the relationship between them and the therapeutic effect should be comprehensively analyzed.

Percutaneous Transforaminal Endoscopic Decompression in Lumbar Discal Cyst

Background: Discal cyst is a rare pathology causing lumbar radiculopathy. Conventional open and microsurgical resection is the most commonly reported surgical treatment for discal cyst. Full-endoscopic surgeries are an efficient but sparsely reported modality. Case Presentation: This is a retrospective study that presents the outcomes of 2 patients with lumbar discal cyst (with radiculopathy in the legs and Visual Analog Scale (VAS) scores of 10 out of 10, classic clinical-radiological presentation features) who were treated with Percutaneous transforaminal endoscopic lumbar discectomy (PTELD) under local anesthesia (LA). Validated Oswestry Disability Index (ODI) and MacNab scores were used for clinical outcome assessment. Additionally, we conducted a review of the literature on full-endoscopic approaches for discal cyst, namely PTELD, percutaneous interlaminar endoscopic lumbar discectomy (PIELD), and transsacral epiduroscopic decompression (SELD). Conclusion: PTELD for lumbar discal cyst is an excellent method to yield a positive long-term out-come, and one of the most minimally invasive full-endoscopic approaches. Key words: Decompression, disc, discal cyst, full endoscopy, lumbar, stenosis, surgery, transforaminal

Study on Influencing Factors of Postoperative Recurrence of Lumbar Disc Herniation Treated by Percutaneous Transforaminal Endoscopic Discectomy

To investigate the influencing factors of percutaneous perforation for lumbar disc herniation. A total of 65 patients with recurrent lumbar disc herniation treated in our hospital from January 2015 to December 2020 (observation group) were selected and 130 patients without recurrence were selected as the control group. 65 patients with recurrent lumbar disc herniation were divided into Group A (n=32) and Group B (n=33). The patients in Group A were treated with percutaneous transforaminal endoscopic lumbar discectomy and the patients in Group B were treated with traditional spinal canal decompression, and nucleus pulposus removal cage fusion and internal fixation. The operation, Japanese orthopaedic association score and Oswestry disability index of the two groups were observed. Logistic regression analysis showed that age, body mass index, Pfirrman classification, incomplete removal of nucleus pulposus during operation and postoperative sedentary work or heavy physical work were the influencing factors of postoperative recurrence (Odds ratio=1.667, 1.545, 1.831, 2.038 and 1.925, p<0.05 ). The operation time, intraoperative blood loss and hospitalization time in Group A were (50.51±3.39) min, (45.51±3.15) ml and (12.03±3.22) d, respectively, which were significantly less than those in Group B (p<0.05). Japanese orthopaedic association score at 3 mo after operation in Group A was (25.51±2.03) points, which was significantly higher than that in Group B (p<0.05), while Oswestry disability index was (20.03±2.62) %, which was significantly lower than that in Group B (p<0.05). The visual analogue scale score of Group A at 3 mo after operation was (2.50±0.44) points, which was significantly lower than that of Group B (p<0.05). Patients with recurrence after percutaneous transforaminal endoscopic treatment effect are still good.

Letter to the Editor Regarding: “Coronavirus Neurosurgical/Head and Neck Drape to Prevent Aerosolization of Coronavirus Disease 2019 (COVID-19): The Lenox Hill Hospital/Northwell Health Solution”

Transforaminal percutaneous endoscopic lumbar discectomy (TPELD) has become an alternative and minimally invasive surgical technique for soft lumbar disc herniation. However, the learning curve has been relatively long and difficult. In the present study, we have summarized the characteristics of the learning curve of TPELD, including the number of cases required to achieve technical proficiency, and discussed the strategies to improve the learning curve.The PubMed, Embase, Cochrane Library, and KoreaMed databases were searched for reports describing the learning curve for TPELD. Clinical studies involving human patients and evaluating the learning curve of TPELD with quantitative data were included. A strict quality assessment was completed, and descriptive statistics were calculated.Of the 6884 screened titles and abstracts, 10 full-text reports, including 958 cases, were included in the analysis. All were cohort studies, which were grouped into early and late groups according to surgeon experience with TPELD. The most commonly used cutoff to differentiate between these groups was 20 (mean, 24.70 ± 18.99 cases; range, 10–72 cases). The most widely used measure was the operative time. Although most studies had reported better results in the operative time or pain scores in the late group, only 1 study had proposed a bona fide learning curve.We found insufficient evidence to support a cutoff point of 20 or other numbers of cases for determining when the learning curve has reached a plateau. Therefore, these numbers should be interpreted with great care, and high-quality prospective studies evaluating the actual learning curve are required.

Unrecognized Dural Tear During Transforaminal Percutaneous Endoscopic Lumbar Discectomy

Journal of Minimally Invasive Spine Surgery & Technique (JMISST) is the official journal of the Korean Minimally Invasive Spine Surgery Society (KOMISS) for the publication of research results about minimally invasive spinal surgery (MISS), including studies in spinal endoscopic surgery, minimally invasive procedure for degenerative spine disease, pain intervention, and minimally invasive surgery for spinal fusion or spine trauma, neuroscience, neurology, molecular biology and biomechanics etc. Articles with helpful information for MISS such as reports of rare cases or technical review of special devices or equipment are also available