Recurrent lumbar disc herniation after conventional discectomy: a prospective, randomized study comparing full-endoscopic interlaminar and transforaminal versus microsurgical revision

Endoscopic Treatment of Lumbar Degenerative Disc Disease: A Narrative Review of Full-Endoscopic and Unilateral Biportal Endoscopic Spine Surgery

BACKGROUND

Degenerative lumbar spine disease is the leading cause of disability and work absenteeism worldwide. Lumbar microdiscectomy became the standard treatment for herniated discs and stenotic disease. With the evolution of different techniques, endoscopic spinal surgery emerged to minimize the surgical footprint while providing at least non-inferior results. Currently, two different types of endoscopic spine procedures are dominating the surgical scenario: "Full-Endoscopic" (FE) and Unilateral Biportal Endoscopic" (UBE) Spine Surgery. The aim of this study is to describe and analyze their indications, their technical characteristicswithitsadvantagesanddisadvantagesofbothtechniquesandtheirfuture trends.

METHODS

We performed a narrative review of the most relevant articles published up to August 2023 through a Pub Med search. The search terms " FE Spine Surgery" and " UBE Spine Surgery" were used. The articles selected, were independently reviewed by 3 authors and 55 full text articles were reviewed.

RESULTS

The FE and UBE Spine Surgery techniques were described. The FE technique is performed with a monoportal access under constant saline irrigation. The FE comprises the transforaminal and the interlaminar approaches, and the indication depends from the pathology to treat, and still remains controversial. UBE can approach also the spine from a posterior, postero lateral,and para spinal route. It uses two different ports addressed to a target with continuous irrigation. The process of establishing these two portals is called triangulation.

CONCLUSIONS

FE and UBE spine surgery have demonstrated outcomes comparable to open surgery, minimizing complications and surgical footprint.

Access to the Lumbosacral Spine: A Current View

The surgical approach to the lumbosacral spine has been the subject of experimental and scientific anatomical studies since the Hippocratic era. However, it was in the 20th century that, with the evolution of asepsis and antibiotic therapy, spine surgery began to evolve at breakneck speed, and the various possibilities of access roads became objects of development and discussion. As a result, pathologies of the lumbosacral spine can be accessed in different ways and positions, from the traditional posterior approach in the prone position to the anterior, oblique, lateral, and endoscopic approaches. The current article brings state-of-the-art access routes to the lumbosacral spine. This article objective is to elucidate the possibilities of accesses the lumbar spine for any purposes, as decompression, fusion, tumour resections, reconstruction or deformity correction, despites type of implants or implants positioning.

Advances and Challenges of Endoscopic Spine Surgery

The purpose of this paper is to review the data supporting current endoscopic surgical techniques for the spine and the potential challenges and future of the field. The origins of endoscopic spine surgery can be traced back many decades, with many important innovations throughout its development. It can be applied to all levels of the spine, with many robust trials supporting its clinical outcomes. Continued clinical research is needed to explore its expanding indications. Although the limitations of starting an endoscopic program can be justified by its cost effectiveness and positive societal impact, challenges facing its widespread adoption are still present. As more residency and fellowship programs include endoscopy as part of their spine training, it will become more prevalent in hospitals in the United States. Technological advancements in spine surgery will further propel and enhance endoscopic techniques as they become an integral part of a spine surgeon's repertoire.

Endoscopic Revision Strategies and Outcomes for Recurrent L4/5 Disc Herniation After Percutaneous Endoscopic Transforaminal Discectomy

Objective

We explore the endoscopic revision and surgical techniques for L4/5 recurrent disc herniation (rLDH) after percutaneous endoscopic transforaminal discectomy (PETD).

Methods

A retrospective study was conducted. From January 2016 to September 2022, 96 patients who underwent percutaneous endoscopic lumbar discectomy for L4/5 rLDH after PETD were enrolled in the study. Based on the revision approach, the patients were divided into PETD group (57 cases) and percutaneous endoscopic interlaminar discectomy (PEID) group (39 cases). Visual Analogue Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and modified MacNab standard were recorded to evaluate the clinical outcomes.

Results

No significant differences were found in the demographic data and intraoperative blood loss between the two groups (P>0.05), but the time of operation and intraoperative X-ray fluoroscopy exposures in the PEID group were significantly less than that in the PETD group (P<0.05). The patients' postoperative clinical indexes gradually improved, and the VAS score, ODI index, and JOA score of the patients in both groups showed significant improvement compared with the preoperative period at the 1-week, 1-month, and 6-month postoperative follow-ups (P < 0.05). There was no serious complication observed during the follow-up.

Conclusion

For recurrent LDH after PETD of L4/5 segments, percutaneous endoscopic revision can achieve satisfactory results. Among them, PEID has a shorter operative and fluoroscopy time and allows avoidance of the scar that forms after the initial surgery, so it can be considered preferred when both procedures can remove the disk well. However, for some specific types of herniation, a detailed surgical strategy is required.

Radiologic Analysis of Causes of Early Recurrence After Percutaneous Endoscopic Transforaminal Discectomy

STUDY DESIGN

Retrospective study.

OBJECTIVE

To analyze the causes of and factors influencing early recurrence after TELD performed in the treatment of lumbar disc herniation.

METHODS

We included 285 patients with single-segment lumbar disc herniation treated using transforaminal endoscopy lumbar discectomy TELD from January 2017 to December 2019 at the First Affiliated Hospital of the University of South China. Patients were classified into early recurrence and non-early recurrence groups based on clinical symptoms and MRI reexamination. Imaging data (eg, disc height index (DHI), Pfirrman grades, base width, postoperative annulus-fibrosus tear size, cross-sectional area of the foramen (CSAF), etc.)were analyzed, and multivariate, binomial logistic regression was utilized to determine which factors were associated with early recurrence after TELD.

RESULTS

A total of 285 patients completed surgery and clinical follow-up, during which 19 patients relapsed within 6 months postsurgery, for an early recurrence rate of 6.7%. There were statistically significant differences between DHI, Pfirrman grades, base width, postoperative annulus-fibrosus tear size, herniation sites, CSAF and Modic changes between the early recurrence and non-early recurrence groups (P < .05). On multivariate logistic regression,the degree of disc degeneration (OR = .747, P = .037), CSAF (OR = 5.255, P = .006), degree of Modic change (OR = 1.831, P = .018) and base width of the herniation (OR = 4.942, P = .003) were significantly correlated with early recurrence after TELD.

CONCLUSIONS

Postoperative annulus-fibrosus tear size, DHI, and location of the disc herniation were associated with early recurrence after TELD. Increased base width of the herniation, severe disc degeneration, decreased CSAF and Modic change were risk factors for early recurrence after TELD.

Translaminar Full Endoscopic Technique with Tom Shidi Needles for Highly- and Dorsally-Migrated Lumbar Disc Herniations

BACKGROUND

Thirty years have passed since Kambin's first clinical series of lumbar disc herniations (LDH) treated by arthroscopic microdiscectomy. Despite several advances in this interim, sequestrated LDHs over the dorsal aspect of the dura, and high-grade up- or downward disc migration have been a relative limitation of the transforaminal endoscopic technique. The interlaminar window was the next step to deal with such highly migrated LDHs. Favorable outcomes were obtained in 70-90% of the patients in the long-term, but recurrence rates remained high (approximately 12%), and the approach could be limited by the size of the interlaminar window. Few relevant studies have addressed the role of translaminar full endoscopic technique for migrated LDHs. To describe an innovative modification of the translaminar full endoscopic approach with Tom Shidi needles.

METHODS

This technical modification is presented in a detailed fashion for treating these challenging LDHs and illustrated through a clinical case.

RESULTS

The patient underwent successful translaminar full endoscopic technique with complete pain resolution postoperatively. The postprocedural course was uneventful. A follow-up imaging showed no evidence of residual LDHs fragments.

CONCLUSIONS

Translaminar full endoscopic technique with Tom Shidi needles is a promising modification of the previously presented interlaminar and translaminar endoscopic routes in the treatment of migrated LDHs to fasten surgical procedures and increase the safety of spinal canal manipulation.

Factors affecting return to work following endoscopic lumbar foraminal stenosis surgery: A single-center series

Background

This study evaluates the factors affecting the return to work of endoscopic surgery for lumbar foraminal stenosis (LFS), including symptoms, functional status, complications, and reoperation rates.

Methods

The authors' retrospective cohort study included 100 consecutive patients (50 males and 50 females) diagnosed with LFS who underwent endoscopic surgery at Trotsky National Research Center of Surgery between January 2018 and December 2021.

Results

There were no significant differences in age and preoperative visual analog scale and Oswestry disability index scores between the male and female groups, time to return to work for different patient groups after undergoing endoscopic lumbar foraminotomy (ELF). However, patients with more severe stenosis and comorbidities may take longer to recover. Confounding factors were patient age, preoperative physical function, and job requirements.

Conclusion

This study confirms that study ELF can effectively improve symptoms associated with lumbar radiculopathy, as well as back pain, and improve patients' quality of life. Comorbidity, smoking status, and complications prolong the time to return to work following ELF surgery compared to healthy subjects.

Functional Outcomes After Discectomy for Recurrent Lumbar Herniation Using the Destandau Endospine System: A Retrospective Study of 44 Patients

Background Recurrent disc herniation is a major cause of morbidity and surgical failure after disc surgery. This study aimed to investigate the feasibility, safety, and effectiveness of the Destandau endospine system (DES) for treating recurrent lumbar disc herniation (LDH). Methodology A total of 44 patients who underwent minimally invasive Destandau endoscopic lumbar discectomy (DELD) for recurrent LDH were included in this study. All data were collected retrospectively. The preoperative and postoperative visual analog scale (VAS) score was used for the evaluation and gradation of pain. The clinical outcome was analyzed according to modified MacNab criteria. The minimum follow-up was two years. Preoperative and postoperative VAS scores were compared using the paired Student's t-test. Statistical significance was set at a p-value <0.05. Results The mean surgical time was 30 ± 20 minutes. The VAS score for leg pain was improved in all cases from 5.9 ± 2.1 to 1.7 ± 1.3 (p< 0.001). In 98% of cases, a successful outcome was noted (excellent or good outcome according to MacNab criteria). In three (7%) patients, incidental durotomy occurred, but there was no neurological worsening, cerebrospinal fluid fistula, or negative influence on the clinical outcome. No recurrence or instability occurred in our series. Conclusions The clinical outcomes of minimally invasive DES for LDH were found to be comparable with the reported success rates of other minimally invasive techniques reported in the existing literature. The dural tear rate was independent of postoperative morbidity and functional outcome. The technique is a safe and effective treatment option for recurrent LDH.

Advantages of Revision Transforaminal Full-Endoscopic Spine Surgery in Patients who have Previously Undergone Posterior Spine Surgery

BACKGROUND

 Revision lumbar spine surgery via a posterior approach is more challenging than primary surgery because of epidural or perineural scar tissue. It demands more extensive removal of the posterior structures to confirm intact bony landmarks and could cause iatrogenic instability; therefore, fusion surgery is often added. However, adjacent segment disease after fusion surgery could be a problem, and further exposure of the posterior muscles could result in multiple operated back syndrome. To address these problems, we now perform transforaminal full-endoscopic spine surgery (TF-FES) as revision surgery in patients who have previously undergone posterior lumbar surgery. There have been several reports on the advantages of TF-FES, which include feasibility of local anesthesia, minimal invasiveness to posterior structures, and less scar tissue with fewer adhesions. In this study, we aim to assess the clinical outcomes of revision TF-FES and its advantages.

METHODS

 We evaluated 48 consecutive patients with a history of posterior lumbar spine surgery who underwent revision TF-FES (at 60 levels) under local anesthesia. Intraoperative blood loss, operating time, and complication rate were evaluated. Postoperative outcomes were assessed using the modified Macnab criteria and visual analog scale (VAS) scores for leg pain, back pain, and leg numbness. We also compared the outcome of revision FES with that of primary FES.

RESULTS

 Mean operating time was 70.5 ± 14.4 (52-106) minutes. Blood loss was unmeasurable. The clinical outcomes were rated as excellent at 16 levels (26.7%), good at 28 (46.7%), fair at 10 (16.7%), and poor at 6 (10.0%). The mean preoperative VAS score was 6.0 ± 2.6 for back pain, 6.8 ± 2.4 for leg pain, and 6.3 ± 2.8 for leg numbness. At the final follow-up, the mean postoperative VAS scores for leg pain, back pain, and leg numbness were 4.3 ± 2.5, 3.8 ± 2.6, and 4.6 ± 3.2, respectively. VAS scores for all three parameters were significantly improved (p < 0.05). There was no significant difference in operating time, intraoperative blood loss, or the complication rate between revision FES and primary FES.

CONCLUSIONS

 Clinical outcomes of revision TF-FES in patients with a history of posterior lumbar spine surgery were acceptable (excellent and good in 73.4% of cases). TF-FES can preserve the posterior structures and avoid scar tissue and adhesions. Therefore, TF-FES could be an effective procedure for patients who have previously undergone posterior lumbar spine surgery.

EFFICACY OF FULL-ENDOSCOPIC INTERLAMINAR AND TRANSFORAMINAL DISCECTOMY FOR LUMBER DISC HERNIATION

A previous study has reported the therapeutic effects of interlaminar/transforaminal approaches under full-endoscopic visualization to treat L5-S1 lumber disc herniation (LDH). However, the comparison of interlaminar/transforaminal approaches to treat other segments of LDH remains unclear.

OBJECTIVE

To evaluate the clinical efficacy of full-endoscopic interlaminar and transforaminal lumbar discectomy to treat LDH.

METHODS

A total of 93 patients with LDH who underwent fully-endoscopic lumbar interlaminar/transforaminal discectomy were retrospectively collected. Patients were divided into a Transforaminal group (n=41) and an Interlaminar group (n=52). Clinical efficacy was evaluated by visual analogue scale (VAS), the Oswestry disability index (ODI), and the modified MacNab scoring system.

RESULTS

Of the 93 patients, involving segments in LDH referred to L3-4, L4-5, and L5-S1. The fluoroscopy times in the Interlaminar group were smaller than that of the Transforaminal group. We found no obvious significances between the Transforaminal and Interlaminar groups regarding operation time, incision length, postoperative landing time, hospitalization, and incision healing time. Postoperative VAS and ODI scores notably improved at follow-up. Besides, almost 90% LDH patients achieved excellent/good outcomes.

CONCLUSION

The full-endoscopic visualization technique via interlaminar and transforaminal approaches safely and effectively treat LDH. Level of Evidence III, Retrospective Study.

Management of incidental durotomies in an integrated Orthopaedic and Neurosurgical Spinal Unit

Introduction

Incidental durotomy (ID) is an intraoperative event associated to prolonged bed rest and hospital stay, antibiotic use, higher patient dissatisfaction, and leg pain among other complications of its postoperative course. Several repair techniques and postsurgical care have been proposed for its management. This study was designed to develop an agreed protocol in cases of ID among Orthopaedic Surgeons (OS) and Neurosurgeons (NS) integrated into a Spinal Surgery Unit.

Research question

Incidental durotomies management protocol.

Materials and methods

From 997 eligible cases operated in Hospital del Mar (Barcelona, Spain) from April 2018 to March 2022, demographic, clinical, surgical and postoperative data was collected for statistical analysis from the morbidity and mortality database, with 79 identified IDs. Redo procedures were significantly associated to OS, and cervical and anterior/lateral approaches to NS, both groups were not comparable.

Results

ID occurred in 7.9% of cases, more frequently after the lockdown (p=0.03), in females (p=0.04), during posterior approaches (p=0.003), and less frequently in the cervical spine (p=0.009). IDs were linked to postoperative infections (p< 0.001) and nerve root damage (p< 0.001). Patients without ID evolved more satisfactorily during the postoperative period (p=0.002), and those with CSF leak (20/79) spent on bed rest more than twice the time as those without (p<0.001). Multivariable logistic regression showed strong association between posterior approaches and ID, between complicated postoperative courses and ID.

Discussion and conclusions

ID is linked to an adverse postoperative recovery, and it should be primarily repaired under microscope, with early mobilization of patients after surgery.

Research Trends of Percutaneous Endoscopic Lumbar Discectomy in the Treatment of Lumbar Disc Herniation Over the Past Decade: A Bibliometric Analysis

Objective

This study aimed to explore the research trends of percutaneous endoscopic lumbar discectomy in treating lumbar disc herniation using bibliometrics over the past ten years.

Methods

Relevant publications on the clinical application of percutaneous endoscopic lumbar discectomy in lumbar disc herniation were searched in the Web of Science Core Collection. Subsequently, the characteristics of all these articles were collected. Visualizing data of annual publications, journals, cited journals, authors, cited authors, countries, institutions, keywords, and cited references was performed by using CiteSpace (6.1.R6).

Results

A total of 642 publications were extracted between 2013 and 2022. The number of publications peaked in the year 2020. The most prolific journal was World Neurosurgery (81), and Spine (597) as the cited journal was the most popular one. China (393) was the most prolific country, followed by South Korea (100). The institution with the most productivity was Tongji University (35). Yue Zhou (20) was the most prolific author, and Sebastian Ruetten (310) was the most cited author. The keyword "interlaminar" was top of research developments with the highest citation burst (8.69). "Lumbar disc herniation", "surgical technique", and "complication" were popular keywords. The surgical procedures and complications of percutaneous endoscopic lumbar discectomy have been the hot topics of recent research.

Conclusion

This study summarized the current situation and development trends of percutaneous endoscopic lumbar discectomy clinical research in the form of visualization, and these findings may help researchers explore new directions in the future.

Percutaneous full endoscopic tumourectomy of a lumbar epidural schwannoma via transforaminal approach: a case report and systematic review of the literature

STUDY DESIGN

Report of three patients undergoing lumbar epidural schwannoma tumourectomy. Percutaneous endoscopy has been routinely used in the treatment of disk herniation but has not been reported in the management of intraspinal tumours.

METHODS

Three patients diagnosed with schwannoma by imaging and pathological examination underwent percutaneous full endoscopic tumourectomy. A 5-mm incision was made, the puncture needle passed through the skin, subcutaneous tissue and the deep fascia and vertebral muscles to the intervertebral foramen area. Next, a working cannula was inserted into the lesion area. Foraminotomy was completed by trephine and microscopic power drill if the foramen was stenosed. Tumour tissue was totally removed piecemeal. After probing the nerve foramen and the nerve root satisfactorily, the working cannula was removed and the incision sutured.

RESULTS

Three patients were operated successfully. Symptoms recovered in all cases and no complication or recurrence was found on follow-up.

CONCLUSIONS

This case report presents a new technique for non-infiltrating extradural lumbar tumour treatment, demonstrating feasibility and safety of percutaneous full endoscopic lumbar tumourectomy.

Percutaneous endoscopic translaminar approach in a patient with pedicle screw malposition and cement leakage

We present a 79-year-old female patient who had L2-5 dynamic stabilization with cement (Polymethylmethacrylate) injection 6 weeks prior. Due to post-operative right radicular pain, a lumbar CT was scheduled in which a malposition of the right L4 screw and cement leakage was observed. Via a percutaneous translaminar endoscopic approach the leaked cement was removed and the portion of the screw in contact with the nerve root was drilled. With this minimal-invasive procedure, the patient was relieved of her radicular pain.

Surgical Strategy and Outcomes of Full Endoscopic Lumbar Discectomy for Recurrent Lumbar Disk Herniation Following a Previous Full Endoscopic Lumbar Discectomy

OBJECTIVE

Recurrent lumbar disc herniation (RLDH) cannot be prevented after full endoscopic lumbar discectomy (FELD), and the optimal surgical treatment for RLDH after FELD remains controversial. The aim of the study was to suggest a surgical strategy for FELD to treat RLDH following a previous FELD and to present surgical outcomes.

METHODS

Between February 2015 and March 2022, 68 patients with RLDH were surgically treated with FELD retrospectively. An original approach was suggested for the treatment of early recurrence (24 h-2 weeks). The full endoscopic transforaminal technique (FETD) was considered for patients requiring local anesthesia, and in RLDH with FETD indications or FEID technological difficulties. The full endoscopic interlaminar technique (FEID) was chosen in RLDH with FEID indications. Both FEID and FETD were suitable if no FEID or FETD technological difficulties existed. Clinical efficacy was evaluated using the visual analog scale (VAS) score, Oswestry disability index (ODI), and modified MacNab criteria. Postoperative follow-up data at 24 h, 3 months, and final-follow-up were recorded. Operation time and clinical outcomes were assessed with t test. p-value < 0.05 was considered statistically significant.

RESULTS

All 68 patients had an average follow-up time of 23.8 months (range, 6-76 months). In the 13 cases of early recurrence, the operation time (32.30 ± 9.67 vs. 58.00 ± 6.16 min) in the original surgical approach group was shorter than that in the changing surgical approach group (p < 0.05). In the 28 cases of L4/5 FETD recurrence (>2 weeks), the operation time (66.17 ± 12.18 vs. 53.60 ± 5.45 min) in the FETD group was more than that in the FEID group (p < 0.05). In the 22 cases of L5S1 recurrence (>2 weeks), the operation time (55.75 ± 8.79 vs. 79.33 ± 6.65 min) in the FEID group was shorter than in the FETD group (p < 0.05). The postoperative VAS and ODI scores at 24 h, 3 months, and final-follow up were all significantly improved, compared with their preoperative counterparts (p < 0.05). Based on the modified MacNab criteria, 88.23% of patients showed excellent or good results. Re-recurrence occurred in three patients at 3 months. No surgical complications were observed in any of the 68 cases.

CONCLUSION

FELD is a safe and effective treatment option for RLDH with previous FELD. For early recurrence, the original approach was suggested. Both FEID and FETD were effective and safe for recurrence (>2 weeks), but FEID seemed more efficient for L4/5 RLDH after previous FETD and for L5S1 RLDH.

Endoscopic versus microscopic discectomy for pathologies of lumbar spine: A nationwide cross-sectional study from a lower-middle-income country

Objective

We conducted a cross-sectional study to assess the preference of spine surgeons between MD for microdiscectomy and endoscopic discectomy (ED) surgery for the management of lumbar pathologies in a lower-middle-income country (LMIC).

Methodology

An online survey assessing the preference of spine surgeons for various lumbar pathologies was developed and disseminated in "Neurosurgery Cocktail" a social media platform. Statistical analyses were performed using SPSS software with a level of significance <0.05.

Results

We received responses from 160 spine surgeons having a median experience of 6.75 years (range 0-42 years) after residency. Most of the spine surgeons preferred MD over ED, preference being homogeneous across all lumbar pathologies. In ED, the interlaminar approach was preferred more frequently than the transforaminal approach. The most commonly chosen contraindication for the interlaminar approach and transforaminal approach was ≥ 3 levels lumbar disc herniation (LDH) (n = 117, 73.1%) and calcified LDH (n = 102, 63.8%), respectively. There was no significant association between the type of approach preferred (MD vs. ED; and interlaminar vs. translaminar endoscopic approach) with the type of workplace and the level of experience.

Conclusion

Spine surgeons were inclined toward MD over ED, due to various reasons, such as a steep learning curve, lack of training opportunities, and upfront expenses. There is a pressing need for the upliftment of ED in LMICs which requires global action.

Complications of Cervical Endoscopic Spinal Surgery: A Systematic Review and Narrative Analysis

BACKGROUND

There are no systematic evidence-based medical data on the complications of endoscopic cervical spinal surgery. This narrative analysis compiled data from various studies that examined endoscopic complications, such as cervical disc herniation and foraminal stenosis. This study aimed to investigate the efficacy and safety of endoscopic surgery in cervical radiculopathy.

METHODS

We searched the PubMed/MEDLINE databases to identify articles on endoscopic spinal surgery, and keywords were set as "endoscopic cervical spinal surgery", "endoscopic cervical discectomy", "endoscopic cervical foraminotomy", and "percutaneous endoscopic cervical discectomy". We analyzed the evidence level and classified the prescribed complications according to the literature. Endoscopic cervical surgery was divided into three categories: full endoscopic anterior, endoscopic posterior, and unilateral biportal approaches. We excluded duplicate publications, studies without full text, studies without complications or incomplete information, and studies that did not provide the necessary data for extraction, animal experiments, or reviews.

RESULTS

Difficulties in swallowing, hematoma, and hoarseness are common complications associated with the anterior cervical approach. In contrast, complications of the posterior approach include nerve root injury, hematoma, and dysesthesia. However, endoscopic cervical spinal surgery, including the full endoscopic anterior, posterior, and unilateral biportal approaches, is a safe and effective treatment for cervical radiculopathy.

CONCLUSIONS

Complications of full endoscopic cervical spinal surgery differ significantly depending on the anterior and posterior approaches. In the anterior approach, swallowing difficulty, recurrent disc, hematoma, and dysphonia are the common complications. In contrast, transient dysesthesia, dural tears, upper limb motor deficits, and persistent arm pain are commonly reported with the posterior approach.

Nomogram for predicting the unfavourable outcomes of percutaneous endoscopic transforaminal discectomy for lumbar disc herniation: a retrospective study

Objective

To investigate and integrate multiple independent risk factors to establish a nomogram for predicting the unfavourable outcomes of percutaneous endoscopic transforaminal discectomy (PETD) for lumbar disc herniation (LDH).

Methods

From January 2018 to December 2019, a total of 425 patients with LDH undergoing PETD were included in this retrospective study. All patients were divided into the development and validation cohort at a ratio of 4:1. Univariate and multivariate logistic regression analyses were used to investigate the independent risk factors associated with the clinical outcomes of PETD for LDH in the development cohort, and a prediction model (nomogram) was established to predict the unfavourable outcomes of PETD for LDH. In the validation cohort, the nomogram was validated by the concordance index (C-index), calibration curve, and decision curve analysis (DCA).

Results

29 of 340 patients showed unfavourable outcomes in the development cohort, and 7 of 85 patients showed unfavourable outcomes in the validation cohort. Body mass index (BMI), course of disease (COD), protrusion calcification (PC), and preoperative lumbar epidural steroid injection (LI) were independent risk factors associated with the unfavourable outcomes of PETD for LDH and were identified as predictors for the nomogram. The nomogram was validated by the validation cohort and showed high consistency (C-index = 0.674), good calibration and high clinical value.

Conclusions

The nomogram based on patients' preoperative clinical characteristics, including BMI, COD, LI and PC, can be used to accurately predict the unfavourable outcomes of PETD for LDH.

Uniportal versus biportal endoscopic spine surgery: a comprehensive review

INTRODUCTION

Endoscopic spine surgery techniques are minimally invasive alternatives to conventional open surgery for degenerative spinal diseases. Clinical studies and meta-analyses have proven the usefulness of uniportal full-endoscopic spine procedures. However, a steep learning curve is a critical barrier for endoscopic procedures. Recently, biportal endoscopic spine surgeries have been developed to make it easier for spine surgeons to learn and perform. Consequently, the biportal approach has gained popularity among aspiring endoscopic spine surgeons. This review compared the characteristics of uniportal and biportal surgeries to help spine surgeons perform endoscopic procedures more effectively.

AREA COVERED

The review analyzed English-language clinical literature in Core databases and compared uniportal and biportal endoscopic spine surgery techniques. Clinical studies have compared the technical principles of both techniques, and the authors suggested appropriate strategies for learning and practicing endoscopic procedures.

EXPERT OPINION

Uniportal, full-endoscopic spine surgery is a minimally invasive procedure that preserves muscles and uses a keyhole approach under local anesthesia. In contrast, biportal surgery is more familiar to a surgeon and can be performed more widely, although the keyhole approach is limited. Aspiring endoscopic spine surgeons can learn either method according to the surgeon's preference and the clinical situation.

Spinal Fusion Versus Repeat Discectomy for Recurrent Lumbar Disc Herniation: A Systematic Review and Meta-Analysis

OBJECTIVE

Recurrent lumbar disc herniation (RLDH) is one of the major causes of failure for primary surgery. Repeat discectomy (RD) and spinal fusion (SF) are 2 surgical options for RLDH. The objective of our study is to compare the effectiveness of SF compared with RD in the treatment of RLDH.

METHODS

We systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Ovid Medline for studies (published between Jan 1, 1959 and July 8, 2022; no language restriction) comparing SF and RD for the RLDH. Odds ratio and weighted mean difference were calculated for binary outcomes and continuous outcomes. The quality of each outcome was graded using the Grading of Recommendations, Assessment, Development and Evaluations criteria.

RESULTS

We identified 5029 studies, of which 11 studies were included. There were 2 randomized controlled trials and the remaining were observational studies. Comparing SF and RD groups, no differences were found in visual analog scales for leg and back and Oswestry Disability Index. Furthermore, the Japanese Orthopaedic Association scores of SF were significantly higher than the RD group. In terms of complications, the incidence of neurological deficit, segmental instability, and re-recurrence is significantly lower with SF than with the RD group. Lastly, the SF group was associated with longer hospital stays and operation time, and more blood loss.

CONCLUSIONS

The pooled evidence suggests that fusion achieves better results than RD for RLDH. The results of this review should be further confirmed by future high-quality randomized controlled trials.

Tubular Microdiscectomy for Recurrent Lumbar Disc Herniation: A Valuable Alternative to Endoscopic Techniques

OBJECTIVE

The efficacy of tubular microdiscectomy (TMD) in the treatment of recurrent lumbar disc herniation (rLDH) is still unclear, especially compared with the endoscopic technique. We performed a retrospective study to analyze this question.

METHODS

We retrospectively included all patients with an rLDH confirmed by magnetic resonance imaging who underwent TMD between January 2012 and February 2019. The general data included sex, age, body mass index, level of rLDH, first surgical approach, reoperation interval, occurrence of dural leak, re-recurrence, and re-reoperation. The clinical outcome was evaluated using a visual analog scale for leg pain, and the modified MacNab criteria were used to evaluate patient satisfaction.

RESULTS

The visual analog scale score for leg pain was statistically significantly reduced from 7.46 preoperatively to 0.80 postoperatively (P < 0.00001), and the patient satisfaction was good or excellent in 85.7% of cases, according to the modified MacNab criteria. Complications occurred in 3 of the 15 included patients: 2 dural tears (13.3%) and 2 re-recurrence (13.3%), but none of the patients underwent a third surgical procedure.

CONCLUSIONS

TMD seems to be an efficient technique for the surgical treatment of leg pain caused by rLDH. In the literature, this technique seems to be at least as good as the endoscopic technique and is easier to master.

Bibliometric analysis and description of research trends on transforaminal full-endoscopic approach on the spine for the last two-decades

OBJECTIVE

The study aims to assess the current development status of transforaminal full-endoscopic spine surgery (TFES) by exploring and analyzing the published literature to obtain an overview of this field and discover the evolution and emerging topics that are underrepresented.

METHODS

Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science Core Collection between January 2002 and November 2022. The descriptive and evaluative analyses of authors, institutes, countries, journals, keywords, and references are compiled. The quantity of research productivity was measured by the number of publications that were published. A quality indicator was thought to be the number of citations. In the bibliometric analysis of authors, areas, institutes, and references, we calculated and ranked the research impact by various metrics, such as the h-index and m-index.

RESULTS

A total of 628 articles were identified in the field of TFES by the 18.73% annual growth rate of research on the subject from 2002 to 2022, constituting the documents are by 1961 authors affiliated with 661 institutions in 42 countries or regions and published in 117 journals. The USA (n = 0.20) has the highest international collaboration rate, South Korea has the highest H-index value (h = 33), and China is ranked as the most productive country (n = 348). Brown univ., Tongji univ., and Wooridul Spine represented the most productive institutes ranked by the number of publications. Wooridul Spine Hospital demonstrated the highest quality of paper publication. The Pain Physician had the highest h-index (n = 18), and the most cited journal with the earliest publication year in the area of FEDS is Spine (t = 1855).

CONCLUSION

The bibliometric study showed a growing trend of research on transforaminal full-endoscopic spine surgery over the past 20 years. It has shown a significant increase in the number of authors, institutions, and international collaborating countries. South Korea, the United States, and China dominate the related areas. A growing body of evidence has revealed that TFES has leapfrogged from its infancy stage and gradually entered a mature development stage.

Factors associated with incomplete clinical improvement in patients undergoing transforaminal endoscopic lumbar discectomy for lumbar disc herniation

PURPOSES

To analyze the clinical and radiographic risk factors that might predict incomplete clinical improvement after transforaminal endoscopic lumbar discectomy (TELD).

METHODS

A retrospective analysis was conducted from 194 consecutive patients who underwent TELD due to lumbar disc herniation (LDH). Patients with incomplete clinical improvement were defined from patient-reported outcomes of poor improvement in pain or disability after surgery and patient dissatisfaction. Clinical and radiographic characteristics were evaluated to identify predicting factors of poor outcomes.

RESULTS

Of 194 patients who underwent TELD procedures, 32 patients (16.5%) had incomplete clinical improvement and 12 patients (6.1%) required revision surgery. The mean ages were 46.4 years and most of the patients suffered from predominant leg pain (48.9%). The most common surgical level was L4-5 (63.9%). Overall, the Oswestry Disability Index (44.3-15), visual analog scores of back pain (4.9-1.8) and leg pain (7.3-1.6) were significantly improved after surgery. Multivariate logistic regression analysis demonstrated that high body mass index, history of previous surgery, preoperative disability, weakness, and disc degeneration were related to incomplete clinical improvement. There were 15 recurrent LDH (7.7%) with a total of 12 revision surgeries (6.2%).

CONCLUSIONS

We identified independent risk factors associated with incomplete clinical improvement following TELD, including overweight, significant preoperative disability or weakness and history of previous surgery. Advanced age, disc degeneration, vacuum phenomenon, and spondylolisthesis were also possible risk factors. Recognizing these risk factors would help decide whether patients are good candidates for TELD, and optimize the surgical planning preoperatively to achieve good surgical results.

Percutaneous endoscopic interlaminar discectomy for L5-S1 calcified lumbar disc herniation: A retrospective study

Background

Calcified lumbar disc herniation (CLDH) is considered to be a special type of lumbar disc herniation (LDH). Percutaneous endoscopic interlaminar discectomy (PEID), with safety and efficacy, has been proved to be a minimally invasive surgery for LDH. However, there are few studies on PEID in the treatment of CLDH at the L5-S1 level. This study aimed to analyze the clinical efficacy of PEID for L5-S1 CLDH.

Methods

From August 2016 to April 2020, we retrospectively analyzed 28 consecutive patients (17 males and 11 females) with L5-S1 CLDH treated with PEID at our institution. All the patients were monitored for more than 1 year postoperatively. The demographic characteristics, surgical results, and clinical outcomes estimated by the visual analog scale (VAS) for leg pain, the Oswestry disability index (ODI), and the modified MacNab criteria were collected.

Results

All patients successfully underwent PEID. The mean operative time and intraoperative blood loss were 65.36 ± 5.26 min and 13.21 ± 4.35 ml, respectively. The VAS for leg pain and ODI scores improved remarkably from 7.54 ± 0.96 to 1.50 ± 0.51 (P &lt; 0.05) and from 69.29 ± 9.91 to 17.43 ± 3.69 (P &lt; 0.05) a year after operation, respectively. According to the modified MacNab criteria of the last follow-up, the excellent and good rates are 92.86%. Two of the patients had complications, one had nerve root injury and the other had postoperative dysesthesia.

Conclusions

PEID achieved good clinical outcomes in the treatment of L5-S1 CLDH, and it was a safe and effective minimally invasive surgery for L5-S1 CLDH.

Percutaneous Endoscopic Lumbar Discectomy for the Treatment of Recurrent Lumbar Disc Herniation: A Meta-analysis

Objective. To evaluate the incidence and safety of clinical complications associated with percutaneous endoscopic lumbar discectomy (PELD) for the treatment of recurrent lumbar disc herniation (RLDH) by meta-analysis. Methods. PubMed, Embase, The Cochrane Library, and Web of Science electronic databases were searched for clinical studies on complications related to the treatment of RLDH with PELD. The search time extended from the databases’ inception until May 2021. RevMan5.4 software was used for meta-analysis after two researchers independently scanned the literature, gathered data, and assessed the bias risk of the included studies. Results. A total of 8 clinical studies, including 1 randomized controlled trial and 7 cohort studies including 906 individuals, were included. According to the results of the meta-analysis, the overall complications ( $\text{OR}=0.18$ , 95% CI: 0.04-0.83, $p=0.03$ ) and dural tear rates ( $\text{OR}=0.11$ , 95% CI: 0.01-0.92, $p=0.04$ ) of PELD were lower than those of traditional fenestration nucleus pulposus removal. Moreover, the PELD group had a greater recurrence rate compared to the MIS-TLIF group ( $\text{OR}=19.71$ , 95% CI: 3.68-105.62, $p=0.0005$ ), and the difference was statistically significant. However, compared with MED and MIS-TLIF, there were no significant differences in the incidence of overall complications, dural tear, nerve root injury, and incomplete nucleus pulposus removal ( $P>0.05$ ). Conclusion. PELD is an effective and safe method for the treatment of recurrent lumbar disc herniation, with a lower incidence of complications and higher safety profile than traditional fenestration nucleus pulposus removal.

Microendoscopic Decompression for Lumbar Disc Herniations: An Analysis of Short and Long Term Patient Reported Outcome Measures

INTRODUCTION

Endoscopic spine surgery is increasingly being used, and techniques, platforms, and applications are rapidly evolving. Despite substantial enthusiasm surrounding these techniques, there is a dearth of longer term patient-reported clinical outcomes. Within the United States in particular, there are yet to be reported large cohort studies with a notable follow-up. We sought to characterize the clinical outcomes of patients undergoing microendoscopic decompression (MED) for lumbar disk herniations.

METHODS

The records of patients with symptomatic lumbar disk herniations who underwent MED from May 2018 to February 2021 within a single practice were reviewed. Paired outcomes scores were evaluated using Patient-Reported Outcomes Measurement Information System parameters. Basic perioperative data including length of stay, estimated blood loss, mean opioid use, complication rate, and rate of revision were tabulated. Paired sample Student t-tests and paired Wilcoxon sign tests were used to compare normally distributed and nonparametric data, respectively.

RESULTS

Thirty-five patients with complete paired patient-reported outcome measures data and a minimum 6-month follow-up were included; 65.7% of the patients were male with a mean age of 47.1 years (SE 1.8). The mean follow-up was 590.6 days (SE 47.7). In total, 34 of the 35 patients (97.1%) were discharged on the day of their procedure. The estimated blood loss was <25 mL for each procedure. The mean opioid use after extubation and before discharge was 10.4 morphine milligram equivalents. At the 2-week follow-up, there were notable improvements in pain metrics and global health components. At the final follow-up, nearly all parameters showed notable improvement that exceeded minimally clinical important difference values. For most parameters, preoperative values outside of the "normal" range were within normal limits on postoperative testing.

DISCUSSION

MED resulted in sustained notable improvement in patient-reported outcome measures that exceeded minimally clinical important difference values at the average follow-up approximating 2 years. These findings substantiate the utility of this technique and additional investment in endoscopic spine technology.

DATA AVAILABILITY

Not publicly available; available upon request.

Comparison of Endoscopic Discectomy Versus Non-Endoscopic Discectomy for Symptomatic Lumbar Disc Herniation: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review.

OBJECTIVE

The authors aimed to systematically compare the effectiveness and safety of endoscopic discectomy (ED) with non-endoscopic discectomy (NED) for treatment of symptomatic lumbar disc herniation (LDH).

METHODS

A systematic search was performed on PubMed, EMBASE, the Cochrane Library and China National Knowledge Infrastructure for randomized controlled trial from inception until August 13, 2020. Trials which investigated multiple operative approaches on lumbar disc herniation were identified without language restrictions.

RESULTS

In total, 25 trials involving 2258 patients with symptomatic LDH were included. Twenty trials performed the comparison between ED and NED. Five trials performed the comparison between percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID). The operative time of micro-endoscopic discectomy (MED) was longer than open discectomy (OD). The length of hospital stay of percutaneous endoscopic lumbar discectomy (PELD) was shorter than fenestration discectomy (FD). Significant differences in intraoperative blood loss volumes were found between PELD with FD and MED with OD. The complication rate of PELD was lower than FD (PELD: 4.3%; FD: 14.6%) and the complication rate of full-endoscopic discectomy (FE) was lower than microscopic discectomy (MD) (FE: 13.4%; MD: 32.1%).

CONCLUSIONS

PELD and FE have the advantage of limiting intraoperative damages. ED and NED can be both considered sufficient to achieve good clinical outcomes. PETD and PEID are able to achieve similar results but the learning curve of PETD was steeper. More independent high-quality RCTs with sufficiently large sample sizes performing cost-effectiveness analyzes are needed.

Percutaneous Endoscopic Lumbar Discectomy for Recurrent Lumbar Disc Herniation: An Updated Systematic Review and Meta-Analysis

OBJECTIVE

This meta-analysis evaluated surgical outcomes following endoscopic or conventional discectomy for recurrent lumbar disc herniation.

METHODS

Medline, Cochrane, EMBASE, and Google Scholar were search until October 16, 2016 using these terms: recurrent lumbar disc herniation, endoscopic surgery, and discectomy. Randomized controlled trials (RCTs), prospective, retrospective, and cohort studies were eligible for inclusion. Pooled difference in mean (PDM) with 95% confidence interval (CIs) or relative risks (RRs) were calculated using fixed-effects methods.

RESULTS

One RCT and 15 studies were included with a total of 820 patients. Patients received endoscopic surgery experienced shorter operation time than those received conventional surgery (PDM: -52.01, 95% CI: -76.84 to -27.18, P < 0.001). A significantly lower risk in complication was displayed in patients received endoscopic surgery compared to those received conventional surgery (RR: 0.209, 95% CI: 0.076-0.581, P = 0.003). No significant difference in the improvement in VAS (PDM: -2.19, 95% CI: -5.78 to 1.39, P = 0.231), length of stay (PDM: -6.44, 95% CI: -13.76 to 0.89, P = 0.085) and re-recurrence rate (PDM: 0.88, 95% CI: 0.22-3.50, P = 0.861) between groups.

CONCLUSIONS

Endoscopic and conventional discectomy reduced patient pain comparably, but endoscopic discectomy had significantly lower operation time and lower risk in complications, which may impact other outcomes such as recovery and healthcare costs. More studies are needed to confirm our findings.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-022-00636-1.

Microdiscectomy for sciatica: reality check study of long-term surgical treatment effects of a Lumbosacral radicular syndrome (LSRS)

PURPOSE

It remains unclear whether the long-term results of RCTs regarding the outcome of microdiscectomy for lumbosacral radicular syndrome (LSRS) are generalizable. The purpose of this study was to determine the external validity of the outcome preseneted in RCTs after microdicectomy for LSRS in a patient cohort from a high-volume spine center.

METHODS

Between 2007 and 2010, 539 patients had a single level microdiscectomy for MRI disk-related LSRS of whom 246 agreed to participate. Questionnaires included visual analogue scores (VAS) for leg pain, RDQ, OLBD, RAND-36 and Likert scores for recovery, leg and back pain. Lumbar re-operation(s) were registered.

RESULTS

Mean age was 51.3, and median time of follow-up was 8.0 years. Re-operation occurred in 64 (26%) patients. Unfavorable perceived recovery was noted in 85 (35%) patients, and they had worse leg and back pain than the 161 (65%) patients with a favorable recovery: median VAS for leg pain 28/100 mm versus 2/100 mm and median VAS for back pain 9/100 mm versus 3/100 mm, respectively. In addition, the median RDQ and OLBD scores differed significantly: 9 vs 3 for RDQ and 26 vs 4 for OLBD, respectively (p < 0.001).

CONCLUSION

In this cohort study, the long-term results after microdiscectomy for LSRS were less favorable than those obtained in RCTs, possibly caused by less strict patient selection than in RCTs. Our findings emphasize that patients, who do not meet the same inclusion criteria for surgery as in RCTs, should be informed about the chances of a less favorable result.

PAIN INTENSITY AND FUNCTIONAL STATUS 30 DAYS AFTER SURGERY: DIFFERENCE BETWEEN TRANSFORAMINAL AND INTERLAMINAR PERCUTANEOUS ENDOSCOPICLUMBAR DISCECTOMIES

ABSTRACT Objective: To compare the differences between transforaminal and interlaminar endoscopic approaches in terms of pain intensity and functionality 30 days after the surgical procedure. Methods: A retrospective cohort study, with patients treated by percutaneous interlaminar or transforaminal endoscopic discectomy at the Spine Service of the ISCMPA, in southern Brazil. Data were collected from the patients’ electronic medical records by two independent physicians. The clinical outcomes of pain intensity and lumbar functionality were evaluated, respectively, using the visual analogue scale and the Oswestry Disability Index. Results: Thirty-six patients were included in the study, with a mean age of 50.8 ± 15.3 years, 19 (52.8%) of whom were males. As for the clinical outcomes for both transforaminal and interlaminar percutaneous endoscopic approaches, we observed a statistically significant reduction in pain intensity (mean difference of 3.5 points, p < 0.001) and a statistically significant improvement in functionality (mean difference of 33.2 points, p < 0.001) when we compared the pre- and 30-day postoperative periods, with no significant differences in terms of approaches. The type of technical approach also differed in relation to the patients’ age, the location, type, and migration of the herniated disc, and the patient’s time in the operating room. Conclusion: There was a similar effect on pain reduction and restoration of lumbar functions, 30 days after percutaneous endoscopic discectomy, in both technical approaches, with no significant differences between them. Level of Evidence III; Retrospective comparative study.

Full-Endoscopic Lumbar Discectomy for Recurrent Lumbar Disc Herniation: A Retrospective Study with Patient-Reported Outcome Measures

Introduction

Revision surgery for recurrent lumbar disc herniation after surgical treatment is at times challenging due to epidural adhesions and scar. This study aimed to review the clinical results and safety of full-endoscopic lumbar discectomy via interlaminar (FELD-IL) and transforaminal (FELD-TF) approaches for revision surgery.

Methods

We conducted a retrospective study including 52 lumbar disc herniation revision patients (mean age, 51.8 years; male/female, 13/39), with 17 FELD-IL and 35 FELD-TF cases. Complication incidences were assessed by reviewing surgical videos and postoperative magnetic resonance images of nerve decompression outcomes. Patients' responses to Japan Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and numerical rating scales (NRS) for lumbar pain, leg pain, and leg numbness were recorded before and during follow-up. The Wilcoxon-signed rank tests were utilized to compare pre- and postoperative group variables.

Results

The average operation time was 33.0 min in FELD-IL and 31.7 min in FELD-TF. Seven FELD-IL cases required lamina excavation with high-speed drill bars for scar tissue dissection from the lamina. Dura injury occurred during the excavation in one case. No complication was noted in the FELD-TF group. Successful decompression of the nerve was achieved in all cases. Complete sets of JOABPEQ and NRS were obtained in 64.5% of FELD-IL and in 82.9% of FELD-TF. The mean follow-up period was 18.6 months. All the subdomain of JOABPEQ and NRS improved significantly postoperative in both groups. There was no difference regarding the improvement of scores between the procedures except NRS for lumbar pain, which was more favorable in FELD-IL. Recurrence of herniation occurred in one patient (6%) after FELD-IL and two patients (6%) after FELD-TF.

Conclusions

Both FELD-IL and FELD-TF are safe and effective revision procedures for recurrent lumbar disc herniation. FELD-TF could be performed employing the same procedure as primary surgery in revisions, regardless of the previous surgical approach.

Comparison of two endoscopic spine surgical techniques

OBJECTIVE

The objective of this study is to compare the clinical outcome among patients who are surgically treated for lumbar disc herniation by transforaminal and interlaminar endoscopy techniques.

METHODS

For the treatment of lumbar disc herniation, 31 patients were assigned to undergo the interlaminar technique and 24 patients the transforaminal technique. They were evaluated using visual analog scale and Oswestry disability index in the preoperative period, in the first postoperative period, and in the 12th month after the procedure. The clinical results between the two techniques were then compared.

RESULTS

Overall, 89.1% of the patients obtained good results, with 12.5% complications in the transforaminal technique and 9.6% in the interlaminar technique.

CONCLUSION

Although both the endoscopic techniques, compared in this study, are safe and effective for the surgical treatment of lumbar herniated disc, the interlaminar technique presented significantly better results and lower rates of complications than the transforaminal technique.

Eight Surgical Interventions for Lumbar Disc Herniation: A Network Meta-Analysis on Complications

Objective: Therapeutic options for lumbar disc surgery (LDH) have been rapidly evolved worldwide. Conventional pair meta-analysis has shown inconsistent results of the safety of different surgical interventions for LDH. A network pooling evaluation of randomized controlled trials (RCT) was conducted to compare eight surgical interventions on complications for patients with LDH. Methods: PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for RCT from inception to June 2020, with registration in PROSPERO (CRD42020176821). This study is conducted in accordance with Cochrane guidelines. Primary outcomes include intraoperative, post-operative, and overall complications, reoperation, operation time, and blood loss. Results: A total of 27 RCT with 2,948 participants and eight interventions, including automated percutaneous lumbar discectomy (APLD), chemonucleolysis (CN), microdiscectomy (MD), micro-endoscopic discectomy (MED), open discectomy (OD), percutaneous endoscopic lumbar discectomy (PELD), percutaneous laser disc decompression (PLDD), and tubular discectomy (TD) were enrolled. The pooling results suggested that PELD and PLDD are with lower intraoperative and post-operative complication rates, respectively. TD, PELD, PLDD, and MED were the safest procedures for LDH according to complications, reoperation, operation time, and blood loss. Conclusion: The results of this study provided evidence that PELD and PLDD were with lower intraoperative and post-operative complication rates, respectively. TD, PELD, PLDD, and MED were the safest procedures for LDH according to complications, reoperation, operation time, and blood loss. Systematic Review Registration: PROSPERO, identifier CRD42020176821.

Percutaneous Endoscopic Interlaminar Discectomy with Modified Sensation-Motion Separation Anesthesia for Beginning Surgeons in the Treatment of L5-S1 Disc Herniation

Purpose

To compare the clinical effects of local anesthesia (LA), general anesthesia (GA) and modified sensation-motion separation anesthesia (MA) in percutaneous endoscopic interlaminar discectomy (PEID) in the treatment of L5/S1 lumbar disc herniation (LDH) for the purpose of guiding junior surgeons.

Methods

Eighty-four patients with L5/S1 LDH underwent PEID using three anesthesia methods. Patients in the LA (26), GA (29) and MA (29) groups received a follow-up examination retrospectively. The general parameters, preparation and anesthesia duration, operative duration, recovery time, incidence of complications, ambulation time, length of hospital stay, incidence of severe complications, and reoperation rate were compared, and clinical outcomes were analyzed using a visual analog scale (VAS), the Oswestry Disability Index (ODI), and the Short-Form Health Survey 36 (SF-36).

Results

MA demonstrated obvious advantages over the other two methods with respect to operative duration and resulted in a better intraoperative experience than LA. The patients in the MA group required less time in bed postoperatively and shorter hospital stays than those in the GA group. The mean postoperative VAS, ODI and SF-36 scores were significantly better than the preoperative scores in all groups (P<0.05), but no significant differences in these scores were found among the three groups (P>0.05). Three cases (3/29) of nervous disorder occurred in the GA group. Two patients (one in the GA group (1/29) and one in the LA (1/26) group) underwent revision surgery, with a total recurrence rate of 2.4% (2/84).

Conclusion

Due to its high safety and good tolerance by patients, MA is a suitable method for spinal surgeons who are inexperienced with PEID in the treatment of L5/S1 disc herniation.

Evaluation of the effectiveness of surgical methods for the treatment of recurrent lumbar disc herniation: a cohort retrospective study

Objective. To compare the effectiveness of surgical methods for treating patients with recurrent lumbar disc herniation.

Material and Methods. The sample consisted of 160 patients operated on in 2014–2019 for recurrent lumbar disc herniation by percutaneous endoscopic discectomy (Group 1), microsurgical discectomy (Group 2), single-level transforaminal interbody fusion (Group 3) and single-level total intervertebral disc replacement (Group 4). The effectiveness of surgical treatment was evaluated using the NRS-11, ODI, and MacNab questionnaires.

Results. Assessment of the pain syndrome severity and the vital activity level of patients revealed significant (p < 0.05) differences in favor of total intervertebral disc replacement. Excellent and good outcomes after arthroplasty according to MacNab criteria were noted in all patients in this group. Similar outcomes were reported in 77.5 % (31/40) of patients in the TLIF group, in 75.1 % (24/32) of patients in the percutaneous endoscopic discectomy group and in 72.6 % (45/62) of patients in the microdiscectomy group. The operation time and length of hospital stay were shorter in the endoscopic and microsurgical discectomy groups (p < 0.001). However, the lower incidence of complications and reoperations was observed in groups of posterior interbody fusion and arthroplasty (p > 0.05).

Conclusion. Arthroplasty with the M6-L implant expands the possibilities of surgery for recurrent lumbar disc herniation. Total intervertebral disc replacement and posterior interbody fusion for recurrent lumbar disc herniation are more effective in comparison with decompressive operations, which is reflected in the improvement of clinical treatment outcomes, reduction of perioperative complications and frequency of repeated interventions.

[Posterior percutaneous endoscopy via vertical anchor technique combined with trench technique for single-segmental central cervical disc herniation]

Objective

To investigate the clinical feasibility, safety, and effectiveness of posterior percutaneous endoscopy via vertical anchor technique combined with trench technique for single-segmental central cervical disc herniation.

Methods

Between July 2017 and August 2019, 13 patients with the single-segmental central cervical disc herniation suffering from various neurologic deficits were treated with posterior percutaneous endoscopy via vertical anchor technique combined with trench technique. There were 6 males and 7 females with an average age of 50.5 years (range, 43-64 years). Disease duration ranged from 3 to 17 months (mean, 9.2 months). The clinical symptoms of 5 cases were mainly neck pain, radiculopathy, and numbness in upper limbs, and the visual analogue scale (VAS) score was 6.60±0.55. The clinical symptoms of 8 cases were myelopathy including upper extremities numbness, weakness, and trouble walking, and the modified Japanese Orthopedic Association (mJOA) score was 12.75±0.71. The surgery-related complications, operation time, and intraoperative blood loss were recorded, and the results of clinical symptoms were measured by VAS scores and mJOA scores.

Results

All procedures were completed successfully, no severe complications such as dural tears or cerebrospinal fluid leakage occurred. The operation time ranged from 83 to 164 minutes (mean, 101.2 minutes). The intraoperative blood loss was 25-50 mL (mean, 33.1 mL). After operation, 12 of 13 cases were followed up 10-24 months (mean, 17.6 months). The VAS scores of patients with preoperative pain symptoms were 2.40±0.55 on the first day after operation and 1.80±0.45 at last follow-up, which were significantly lower than those before operation ( P<0.05). The mJOA scores of patients with the symptoms of spinal cord injury were 12.63±0.52 on the first day after operation and 14.29±0.95 at last follow-up, and the score at last follow-up was significantly higher than that before operation ( P<0.05). Acute extremities weakness occurred for the postoperative hematoma formation in 1 case (disc herniation at C _{4, 5}) presented with myelopathy preoperatively, and muscle strength was recovered after the clearance of hematoma and spinal cord decompression under percutaneous endoscopy.

Conclusion

Posterior percutaneous endoscopy via vertical anchor technique and trench technique for single-segmental central cervical disc herniation was clinical feasible, safe, and effective, and could be an alternative approach to the treatment of central cervical disc herniation.

Comparison of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Discectomy in the Treatment of Adolescent Lumbar Disc Herniation: A Retrospective Analysis

OBJECTIVE

To compare and analyze efficacy and safety of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar discectomy (OLD) for adolescent lumbar disc herniation.

METHODS

Clinical data of 257 patients with single-segment adolescent lumbar disc herniation who underwent surgical treatment from January 2015 to December 2019 were retrospectively collected. The patients were divided into PELD and OLD groups based on the surgical method used. Propensity score matching was performed using preoperative baseline data of patients in both groups, and some patients in both groups were selected for comparative study. Clinical and follow-up data were assessed and compared.

RESULTS

There was no statistically significant difference in preoperative baseline data between the 2 groups of patients after propensity score matching. Visual analog scale and Oswestry Disability Index scores improved in both groups postoperatively and at each follow-up time point (P < 0.05). However, visual analog scale scores on the first postoperative day and Oswestry Disability Index scores at 3 months postoperatively were lower in the PELD group than in the OLD group (P < 0.05). Duration of surgery, intraoperative blood loss, and duration of postoperative hospitalization were lower in the PELD group than in the OLD group (P < 0.05). There was no statistically significant difference between the 2 groups when comparing complication and recurrence rates (P >0.05).

CONCLUSIONS

Both PELD and OLD are effective and safe surgical techniques for treatment of adolescent lumbar disc herniation. However, compared with OLD, PELD is more advantageous for rapid symptom relief and improving postoperative quality of life with a low rate of complications and recurrence.

Percutaneous Endoscopic Lumbar Discectomy via Transforaminal Approach Combined with Interlaminar Approach for L4/5 and L5/S1 Two-Level Disc Herniation

Objective

The purpose of the present study was to discuss a new surgical strategy that combines percutaneous endoscopic transforaminal discectomy (PETD) with percutaneous endoscopic interlaminar discectomy (PEID) for L4/5 and L5/S1 two‐level disc herniation.

Methods

This was a retrospective study. A total of 19 patients with L4/5 and L5/S1 two‐level lumbar disc herniation (LDH) who underwent percutaneous endoscopic lumbar discectomy (PELD) in our hospital from January 2015 to June 2016 were retrospectively examined. The average age of these 19 patients was 42.21 ± 14.88 years old, including 12 men and 7 women. One experienced surgeon who had carried out more than 3000 lumbar surgeries performed PELD for these patients. During the PELD surgery, the transforaminal approach was adopted for L4/5 level disc herniation and the interlaminar approach was adopted for L5/S1 level disc herniation. The demographic data, operation time (min), fluoroscopy times, hospital stay (days), and complications were recorded and analyzed. The visual analogue scale (VAS), Oswestry disability index (ODI) scores, and the modified MacNab criteria were used to evaluate the surgical outcomes. MRI was conducted to evaluate the radiographic improvement.

Results

All patients underwent PELD via the transforaminal approach combined with the interlaminar approach successfully and achieved satisfactory efficacy. The follow‐up points were 3, 12, and 18 months. The average hospital stay (days) and the average follow up (months) were 3.32 ± 0.98 and 18.63 ± 3.84, respectively. The operation time and fluoroscopy times were 85.79 ± 12.90 min and 39.05 ± 4.59 times, respectively. The fluoroscopy times (frequency) for L4/5 and L5/S1 were 26.95 ± 6.41 and 12.11 ± 3.49 (t = 7.00, P < 0.05). Furthermore, there was no significant difference for fluoroscopy times between male and female patients (t = 0.89, P = 0.99). The preoperative back pain (VAS‐Back) and the last follow‐up VAS‐Back were 5.58 ± 2.01 and 2.37 ± 1.01, respectively (t = 7.14, P < 0.05). The preoperative leg pain (VAS‐Leg) and the last follow‐up VAS‐Leg were 7.00 ± 1.56 and 1.63 ± 1.01, respectively (t = 20.97, P < 0.05). There were significant differences between preoperative VAS‐Back and the last follow‐up VAS‐Back in men (t = 4.61, P < 0.05) and women (t = 6.57, P < 0.05). In addition, there was significant differences between preoperative VAS‐Leg and the last follow‐up VAS‐Leg in men (t = 13.48, P < 0.05) and women (t = 26.87, P < 0.05). There were significant differences between preoperative ODI scores (44.84 ± 10.82%) and the last follow‐up ODI scores (11.12 ± 5.80%) (t = 10.92, P < 0.05). Preoperative ODI scores and the last follow‐up ODI scores were significantly different for men (t = 8.80, P < 0.05) and women (t = 6.63, P < 0.05). All patients received significant pain relief and functional improvement after the surgery. Except for two cases of postoperative dysesthesia and one dural tear, no severe complications occurred. The dysesthesia symptoms of these two patients disappeared within 1 week with the application of dexamethasone and neurotrophic drugs and the dural tear case also recovered well as the dural laceration was small. No poor results were reported and 89.47% of patients achieved excellent or good recovery.

Conclusion

Percutaneous endoscopic lumbar discectomy via the transforaminal approach combined with the interlaminar approach under epidural anesthesia can treat L4/5 and L5/S1 two‐level disc herniation safely and effectively.

Invasive Treatments for Low Back Disorders

OBJECTIVE

This abbreviated version of the American College of Occupational and Environmental Medicine's Low Back Disorders guideline reviews the evidence and recommendations developed for invasive treatments used to manage low back disorders.

METHODS

Comprehensive systematic literature reviews were accomplished with article abstraction, critiquing, grading, evidence table compilation, and guideline finalization by a multidisciplinary expert panel and extensive peer-review to develop evidence-based guidance. Consensus recommendations were formulated when evidence was lacking and often relied on analogy to other disorders for which evidence exists. A total of 47 high-quality and 321 moderate-quality trials were identified for invasive management of low back disorders.

RESULTS

Guidance has been developed for the invasive management of acute, subacute, and chronic low back disorders and rehabilitation. This includes 49 specific recommendations.

CONCLUSION

Quality evidence should guide invasive treatment for all phases of managing low back disorders.

Learning Curve for Interlaminar Endoscopic Lumbar Discectomy: A Systematic Review

BACKGROUND

Interlaminar endoscopic lumbar discectomy (IELD) is an efficient surgical treatment for lumbar disc herniation. However, this minimally invasive procedure requires a considerable learning curve that has not yet been standardized. This review aimed to evaluate the learning curve's characteristics, including the cutoff point required to achieve technical proficiency and to discuss appropriate training methods.

METHODS

We systematically searched the core databases (PubMed, Embase, and Cochrane Library) for clinical studies that evaluated the learning curve using quantitative data. We performed a quality assessment using the Newcastle-Ottawa scale. We also compared descriptive statistics, including operative time and other variables before and after the cutoff point.

RESULTS

Six studies reporting 302 cases of IELD were selected from 7188 screened articles. The cutoff point was randomly set in 3 studies and determined as the curve's asymptote in 3 studies. The mean value for the cutoff point was 22.17 ± 12.40 cases (range: 10-43 cases) and mainly determined based on the operative time, which was shorter in the late group than that in the early group (P < 0.05). The cutoff points were not significant for patient outcome parameters such as pain score, functional result, surgical failure, or complications.

CONCLUSIONS

The evidence of published studies regarding the learning curve for the IELD technique is insufficient. The reported cutoff points may be significant only for task efficiency. Moreover, they may not represent the asymptote of the curve. Future studies should evaluate the actual plateau points using patient outcome data.

Percutaneous endoscopic lumbar discectomy compared with other surgeries for lumbar disc herniation: A meta-analysis

OBJECTIVE

This meta-analysis was performed to investigate whether percutaneous endoscopic lumbar discectomy (PELD) had a superior effect than other surgeries in the treatment of patients with lumbar disc herniation (LDH).

METHOD

We searched PubMed, Embase, and Web of Science through February 2018 to identify eligible studies that compared the effects and complications between PELD and other surgical interventions in LDH. The outcomes included success rate, recurrence rate, complication rate, operation time, hospital stay, blood loss, visual analog scale (VAS) score for back pain and leg pain, 12-item Short Form Health Survey (SF12) physical component score, mental component score, Japanese Orthopaedic Association Score, Oswestry Disability Index. A random-effects or fixed-effects model was used to pool the estimate, according to the heterogeneity among the included studies.

RESULTS

Fourteen studies (involving 2,528 patients) were included in this meta-analysis. Compared with other surgeries, PELD had favorable clinical outcomes for LDH, including shorter operation time (weight mean difference, WMD=-18.14 minutes, 95%CI: -25.24, -11.05; P < .001) and hospital stay (WMD = -2.59 days, 95%CI: -3.87, -1.31; P < .001), less blood loss (WMD = -30.14 ml, 95%CI: -43.16, -17.13; P < .001), and improved SF12- mental component score (WMD = 2.28, 95%CI: 0.50, 4.06; P = .012)) and SF12- physical component score (WMD = 1.04, 95%CI: 0.37, 1.71; P = .02). However, it also was associated with a significantly higher rate of recurrent disc herniation (relative risk [RR] = 1.65, 95%CI: 1.08, 2.52; P = .021). There were no significant differences between the PELD group and other surgical group in terms of success rate (RR = 1.01, 95%CI: 0.97, 1.04; P = .733), complication rate (RR = 0.86, 95%CI: 0.63, 1.18; P = .361), Japanese Orthopaedic Association Score score (WMD = 0.19, 95%CI: -1.90, 2.27; P = .861), visual analog scale score for back pain (WMD = -0.17, 95%CI: -0.55, 0.21; P = .384) and leg pain (WMD = 0.00, 95%CI: -0.10, 0.10; P = .991), and Oswestry Disability Index score (WMD = -0.29, 95%CI: -1.00, 0.43; P = .434).

CONCLUSION

PELD was associated with better effects and similar complications with other surgeries in LDH. However, it also resulted in a higher recurrence rate. Considering the potential limitations in the present study, further large-scale, well-performed randomized trials are needed to verify our findings.

Feasibility of Unilateral Approach for Bilateral Decompressive Endoscopic Spinal Surgery for Lumbar Stenosis to Improve Back and Leg Pain: A Consecutive Single-Center Series of 60 Patients

Introduction: Endoscopic surgery is one of the methods that achieve the goal of decompression while minimizing collateral tissue damage. Its efficacy and safety have been supported by numerous studies. There is a plethora of studies on lumbar stenosis regarding the outcomes and related issues in endoscopic spine surgery. However, few studies evaluated the outcome of the decompressive lumbar spine surgery. The present study aims to analyze the outcome of a unilateral approach to endoscopic surgery for lumbar stenosis using the visual analog scale (VAS), the Oswestry Disability Index (ODI), and MacNab's criteria.

Methods: This is a retrospective study (level IV) conducted between January 2009 and December 2013 on 60 patients who underwent endoscopic interlaminar decompressive spine surgery (Destandau method) for lumbar degenerative spinal stenosis in the Hospital Universiti Sains Malaysia. The clinical outcome was measured pre-operatively and post-operatively for VAS: for back and leg pain, motor and sensory grading, the ODI, and MacNab's criteria. A paired t-test was used for statistical analysis.

Results: The mean age of patients was 60.82 years comprising 23 males (38.3%) and 37 females (61.7%). The mean follow-up period was 30.1 months (range = 17.2–43 months). The mean operation time was 183.6 min (ranging from 124.8 to 242.4 min), and the mean blood loss was 150.18 mL (ranging from 30.82 to 269.54 mL). Post-operatively, mean hospital stay was 2.45 days (ranging from 1.34 to 3.56 days). The most frequently involved level was L4/L5 in 51 patients (52.6%), followed by L3/L4 in 19 patients (19.6%), L5/S1 in 24 patients (24.7%), and L2/L3 in three patients (3.1%). Improvement in the post-operative VAS for back and leg pain and the ODI for pre-operation and post-operation was statistically significant (p < 0.001). Conversely, the reduction in neurological status was statistically insignificant. Based on MacNab's criteria, 88.4% showed excellent to good outcomes.

Conclusion: To summarize, unilateral percutaneous endoscopic spine surgery to achieve the bilateral decompression in lumbar stenosis provides excellent yet safe and effective outcomes. It improves back and leg pain and patients' function significantly.

Endoscopic interlaminar lumbar discectomy: How to decrease the learning curve

Background:

Herniated lumbar disc is a common cause of lumbosacral pain. Endoscopic interlaminar lumbar discectomy (ILD) is a well-established technique that provided comparable results to micro-discectomy. The aim of the study is to describe the learning curve of endoscopic ILD and explore measures that could improve effectiveness and decrease blood loss and operative time with accumulation of reasonable experience.

Methods:

This retrospective cohort study included 65 patients presenting with symptomatic herniated lumbar disc who underwent endoscopic ILD. Patients were divided into two groups: Group I (standard technique) and Group II (modified technique). Collected data included patients’ age, gender, preoperative manifestations, visual analog score (VAS) for pain, Oswestry Disability Index (ODI), disc level, operative time, intraoperative blood loss, complications, and follow-up data at 1, 6, and 12 months postoperatively. Primary outcomes included total operative time, amount of intraoperative blood loss, and post-operative improvement in pain. Secondary outcomes included intraoperative complications, rate of conversion to open surgery, and recurrence.

Results:

Post-operative VAS and ODI improved significantly in both groups. Mean total surgical time and intraoperative blood loss were significantly lower in Group II compared to Group I (P < 0.001). The learning curves for operative time and intraoperative blood loss were shallow in Group I, and almost flattened in Group II. Complications were recorded in only three cases, and no symptomatic recurrences were reported.

Conclusion:

The learning curve of endoscopic ILD was shallow with standard technique, indicating difficulties in mastering the procedure. The proposed modified technique helped reaching the required level of proficiency in the early phase of the curve, providing a significant reduction in operative time and blood loss, with comparable effectiveness and safety as the standard technique.

Bilateral translaminar osseous-channel assisted percutaneous full-endoscopic ligamentectomy decompression for thoracic myelopathy due to ossification of the ligamentum flavum: a technical note

Introduction

A variety of surgical procedures have been introduced to treat patients with thoracic myelopathy (TM) caused by ossification of the ligamentum flavum (OLF). However, they are accompanied by significant trauma and risk, and their surgical outcomes are not always satisfactory.

Aim

To describe a bilateral translaminar osseous-channel assisted posterior percutaneous full-endoscopic ligamentectomy decompression (p-PELD) technique as a novel minimally invasive procedure for treating patients with TM due to OLF.

Material and methods

A 51-year-old female patient with persistent thoracolumbar back pain and progressive numbness in the bilateral lower extremities for 2 years underwent percutaneous vertebroplasty (PVP) for T11 osteoporotic compression fractures (OCF) in a regional hospital one week prior to hospitalization. TM caused by canal stenosis and dorsal spinal cord compression at T10/11 secondary to OLF and an OCF at T11 were diagnosed based on clinical presentations and radiologic examinations. After bilateral p-PELD for TM was performed at T10/11, the result was confirmed based on postoperative radiographic and clinical results.

Results

The bilateral OLF was completely removed by the p-PELD technique. No complications were encountered, and her symptoms were sufficiently improved after surgery. The VAS score was 6 points preoperatively and decreased to 0 points at the last follow-up (24 months). The modified Japanese Orthopaedic Association (mJOA) score improved from 2 points preoperatively to 10 points at the final follow-up.

Conclusions

As a minimally invasive technique, the bilateral translaminar osseous-channel assisted p-PELD procedure provided precise and sufficient decompression for the treatment of OLF-related TM.

Successful Introduction of Full-Endoscopic Lumbar Interlaminar Discectomy in Sweden

BACKGROUND

The introduction of full-endoscopic lumbar discectomy (FELD) procedures has made it possible to challenge microscopic discectomy as the gold standard method to treat lumbar disc herniations.

PURPOSE

The aim of the present study is to investigate the introductory-phase postoperative clinical improvement for FELD patients regarding leg pain, patient-reported outcome measurements (PROMs), complications, reoperations, and learning curve analysis.

METHODS

All patients who underwent FELD at Sahlgrenska University Hospital, Sweden, were prospectively included during 2013- 2017. A total of 92 patients were enrolled and followed up for 1 year. The characteristics of the study population, degree of leg pain, complications, learning curve, and PROMs were retrieved from patient records and the National Quality Register for Spine Surgery (Swespine).

RESULTS

The postoperative results demonstrated major improvements; leg pain measured by a numerical rating scale (0-10) decreased from 7.4 ± 2.25 to 2.76 ± 2.70, with a mean improvement of -4.54, (-3.62-5.46) 95% confidence interval (CI). The Oswestry Disability Index decreased by 30.48 (-36.27-23.73) with a 95% CI, and the EuroQol-5D increased by 0.39 (0.21-0.57) 95% CI. An assessment of the final surgical result showed that 91.6% ranked their general situation as better or much better. Specifically, regarding postoperative leg pain, 87% regarded their leg pain as completely gone, much better, or somewhat better, while 13% regarded their leg pain as unchanged or worse. A learning curve analysis showed that for every 10th FELD procedure performed; the duration of surgery decreased by 2 minutes.

CONCLUSIONS

In our study, the introduction of FELD as a safe, quick procedure for the treatment of lumbar disc herniations can yield significant gains in patient-reported outcome measurements and pain reduction. The rate of recurrence and complications is comparable to that of standard surgery.

Learning Curve for Transforaminal Percutaneous Endoscopic Lumbar Discectomy: A Systematic Review

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

A Historical Review of Endoscopic Spinal Discectomy

As an essential component of minimally invasive spine surgery, endoscopic spine surgery (ESS) has continuously evolved and has been accepted as a practical procedure by the worldwide spine community. Especially for lumbar disc herniation (LDH), the percutaneous endoscopic or full-endoscopic discectomy technique has been scientifically proven through randomized controlled trials and meta-analyses to be a good alternative to open discectomy. The initial concept of endoscopic spine discectomy was concerned with indirect disc decompression using various instruments such as blind forceps, a nucleotome, laser, radiofrequency coblation, and some chemical agents. The main surgical field has been shifted from the intradiscal space to the epidural space. Precise and selective discectomy for extruded LDH in the epidural space under high-quality endoscopic visualization is now feasible. Furthermore, the medical applications of ESS is broadening to include spinal stenosis, segmental instability, infection, and even intradural lesions. In this review article, I describe the history of endoscopic spine discectomy and decompression techniques, as well as evolution of the paradigm. This history may help indicate the future of practical ESS.