Learning curve of percutaneous endoscopic transforaminal lumbar discectomy by a single surgeon

Learning Curve of Endoscopic Lumbar Discectomy - A Systematic Review and Meta-Analysis of Individual Participant and Aggregated Data

STUDY DESIGN

A systematic review and meta-analysis of individual participant and aggregated data.

OBJECTIVES

To define the learning curves of endoscopic discectomies using unified statistical methodologies.

METHODS

Searches returned 913 records, with 118 full-text articles screened. Studies of endoscopic lumbar spine surgery reporting outcomes by case order were included. Mixed-effects nonlinear, logistic, and beta meta-regressions prdwere conducted to define the learning curves.

RESULTS

13 studies involving 864 patients among 15 surgeons were included in total. For transforaminal endoscopic discectomy, the estimated operating time for the first case was 95 min [CI: 87-104], and the estimated plateau was 66 minutes [CI: 51-81]. An estimated 21 cases [CI: 18-25] were required to overcome 80% of this deficit, but near-plateau performance was expected only after 59 cases [CI: 51-70]. The estimated risk of surgical complications on the first case was 25% [CI: 11%-46%], with an 80% reduction in relative risk requiring an estimated 41 cases. The expected postoperative VAS leg pain score after the first case was 2.7 [CI: 1.8-3.8], with an 80% improvement requiring an estimated 96 cases. Similar numbers were required to overcome the learning curves in interlaminar and biportal endoscopic discectomies.

CONCLUSIONS

Approximately 60 cases are required to achieve proficiency in endoscopic lumbar spine surgery, although the greatest part of the learning curve can be overcome with 20 cases. This should be considered when designing implementation programmes for surgeons and service providers that wish to incorporate endoscopic spinal surgery into their practice.

Learning curve analyses in spine surgery: a systematic simulation-based critique of methodologies

BACKGROUND CONTEXT

Various statistical approaches exist to delineate learning curves in spine surgery. Techniques range from dividing cases into intervals for metric comparison, to employing regression and cumulative summation (CUSUM) analyses. However, their inherent inconsistencies and methodological flaws limit their comparability and reliability.

PURPOSE

To critically evaluate the methodologies used in existing literature for studying learning curves in spine surgery and to provide recommendations for future research.

STUDY DESIGN

Systematic literature review.

METHODS

A comprehensive literature search was conducted using PubMed, Embase, and Scopus databases, covering articles from January 2010 to September 2023. For inclusion, articles had to evaluate the change in a metric of performance during human spine surgery across time/a case series. Results had to be reported in sufficient detail to allow for evaluation of individual performance rather than group/institutional performance. Articles were excluded if they included cadaveric/nonhuman subjects, aggregated performance data or no way to infer change across a number of cases. Risk of bias was assessed using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool. Surgical data were simulated using Python 3 and then examined via multiple commonly used analytic approaches including division into consecutive intervals, regression and CUSUM techniques. Results were qualitatively assessed to determine the effectiveness and limitations of each approach in depicting a learning curve.

RESULTS

About 113 studies met inclusion criteria. The majority of the studies were retrospective and evaluated a single-surgeon's experience. Methods varied considerably, with 66 studies using a single proficiency metric and 47 using more than 1. Operating time was the most commonly used metric. Interval division was the simplest and most commonly used method yet inherent limitations prevent collective synthesis. Regression may accurately describe the learning curve but in practice is hampered by sample size and model choice. CUSUM analyses are of widely varying quality with some being fundamentally flawed and widely misinterpreted however, others provide a reliable view of the learning process.

CONCLUSION

There is considerable variation in the quality of existing studies on learning curves in spine surgery. CUSUM analyses, when correctly applied, offer the most reliable estimates. To improve the validity and comparability of future studies, adherence to methodological guidelines is crucial. Multiple or composite performance metrics are necessary for a holistic understanding of the learning process.

Is Close Supervision by a Senior Surgeon Necessary During the Initial Days of Performing Endoscopic Lumbar Discectomy? A Retrospective Comparative Study between Two Fellowship Trained Surgeons to Assess the Learning Curve

Objectives

Endoscopic lumbar discectomy is a minimally invasive technique with a steep learning curve. The studies in the literature base the learning curve on the operative duration. We conducted this study to determine the learning curve based on the presence or absence of supervision by an experienced surgeon.

Materials and Methods

This study involved two spine surgeons (surgeon A and surgeon B), who after their fellowship training from the same institute started practising in two different hospitals with different settings. The data of the first 80 patients operated by these two surgeons were extracted, and the patients were followed up for a minimum of 1 year. The data were split into first 30 cases and late 50 cases, which were compared to see the difference between the two surgeons.

Results

The first 30 cases were evaluated between the two surgeons, and the most significant difference between the two was the operative duration. There was difference between the two surgeons in approach towards migrated and foraminal/extra foraminal discs (P = 0.02). The surgeon B started operating on upper lumbar levels in his later 50 cases, but the foraminal and extraforaminal disc herniations were rarely treated by surgeon B.

Conclusions

Endoscopic discectomy when supervised by senior faculty helps to reduce the operative duration especially in the initial phases of a surgeon's career. The surgeon under the supervision of a senior faculty performs more of migrated and foraminal herniated discs.

Percutaneous endoscopic transforaminal discectomy and unilateral biportal endoscopic discectomy for lumbar disc herniation: a comparative analysis of learning curves

OBJECTIVE

The purpose of this study was to investigate the learning curve of percutaneous endoscopic transforaminal discectomy (PETD) and interlaminar unilateral biportal endoscopic discectomy (UBED) in the treatment of lumbar disc herniation (LDH).

METHODS

Between 2018 and 2023, 120 consecutive patients with lumbar disc herniation (LDH) treated by endoscopic lumbar discectomy were retrospectively included. The PETD group comprised 87 cases, and the UBED group comprised 33 cases. Cumulative sum analysis was used to evaluate the learning curve, with the occurrence of complications or unresolved symptoms defined as surgical failure, and variables of different phases of the learning curve being compared.

RESULTS

The learning curve analysis identified the cutoff point at 40 cases in the PETD group and 15 cases in the UBED group. In the mastery phase, both PETD and UBED demonstrated a significant reduction in operation times (approximately 38 min for PTED and 49 min for UBED). In both PETD and UBED groups, the surgical failure rates during the learning and mastery phases showed no statistically significant differences. The visual analogue scale at the last follow-up was significantly lower than before surgery in both the PETD and UBED groups.

CONCLUSION

PETD and UBED surgery are effective in the treatment of LDH with a low incidence of complications. However, achieving mastery in PETD necessitates a learning curve of 40 cases, while UBED requires a minimum of 15 cases to reach proficiency.

Evolution of the Transforaminal Lumbar Interbody Fusion (TLIF): From Open to Percutaneous to Patient-Specific

The transforaminal lumbar interbody fusion (TLIF) has seen significant evolution since its early inception, reflecting advancements in surgical techniques, patient safety, and outcomes. Originally described as an improvement over the posterior lumbar interbody fusion (PLIF), the TLIF began as an open surgical procedure, that notably reduced the need for the extensive neural retractation that hindered the PLIF. In line with the broader practice of surgery, trending toward minimally invasive access, the TLIF was followed by the development of the minimally invasive TLIF (MIS-TLIF), a technique that further decreased tissue trauma and postoperative complications. Subsequent advancements, including Trans-Kambin's Triangle TLIF (percLIF) and transfacet LIF, have continued to refine surgical access, minimize surgical footprint, and reduce the risk of injury to the patient. The latest evolution, as we will describe it, the patient-specific TLIF, is a culmination of the aforementioned adaptations and incorporates advanced imaging and segmentation technologies into perioperative planning, allowing surgeons to tailor approaches based on individual patient anatomy and pathology. These developments signify a shift towards more precise methods in spine surgery. The ongoing evolution of the TLIF technique illustrates the dynamic nature of surgery and emphasizes the need for continued adaptation and refinement.

Outcome of Percutaneous Endoscopic Lumbar Discectomy in Relation to the Surgeon's Experience: Propensity Score Matching

Percutaneous endoscopic lumbar discectomy (PELD) presents a challenging learning curve, and the correlation between surgeon experience and clinical outcomes remains contentious. This retrospective study aimed to compare the outcomes of PELD performed by a single surgeon at beginner and experienced stages. Propensity score matching selected 150 patients (75 per group) with a minimum 3-year follow-up. Clinical and radiological outcomes, perioperative complications, and adverse events were assessed. Baseline characteristics, pain improvement, patient satisfaction, and radiological outcomes did not differ between the groups. However, operation time was longer in the beginner group than in the experienced group (57.5 min [IQR, 50.0-70.0] versus 50.0 min [IQR, 45.0-55.0], p < 0.001). The beginner group had higher perioperative complication rates (eight patients [10.7%] versus one patient [1.3%], with a hazard ratio of 8.836 [95% CI, 1.077-72.514], p = 0.034) and lower 3-year survival without adverse events (19 patients [25.3%] in the beginner group and 10 patients [13.3%] in the experienced group, p = 0.045). Our findings indicate that the clinical outcomes were more favorable in patients operated on at the experienced stage compared to those treated at the beginner stage.

Comparison of Cervical Biportal Endoscopic Spine Surgery and Anterior Cervical Discectomy and Fusion in Patients with Symptomatic Cervical Disc Herniation

Background: We aimed to analyze the clinical outcomes and effectiveness of cervical biportal endoscopic spine surgery (C-BESS) and anterior cervical discectomy and fusion (ACDF) in patients with symptomatic cervical disc herniation. Methods: This study was a retrospective chart review of four-year clinical data involving 318 cases of symptomatic cervical disc herniation, with 156 patients undergoing the ACDF and 162 patients receiving the C-BESS. Preoperative and postoperative one-year data were collected. Results: The numeric rating scale and neck disability index showed statistically significant improvement for both ACDF and C-BESS groups. While showing a longer operation time and more blood loss during surgery compared to the ACDF group, the C-BESS group demonstrated a learning effect as the surgeon's proficiency increased with more cases. There was no significant difference in the postoperative length of hospitalization between the two methods. The subgroup with predominant arm pain revealed the statistical difference in arm pain intensity changes between the two groups (p < 0.001). The rates of complication were 2.6% for the ACDF group and 1.9% for the C-BESS group. Conclusions: C-BESS and ACDF are effective surgical treatments for patients with symptomatic single-level cervical disc herniation in relieving relevant pain intensities and pain-related disabilities.

The learning curve of robot-assisted laparoscopic pyeloplasty in children

To explore the learning curve of robot-assisted laparoscopic pyeloplasty (RALP) in children. The clinical data, surgical information, and postoperative complications of consecutive cases of RALP performed by the same surgeon in Shanghai Children's Hospital from January 2014 to July 2020 were retrospectively analyzed; the surgeon is a senior pediatric urologists who is proficient in laparoscopic pyeloplasty; the data consist of console time (CT), suture method when anastomosing ureteropelvic junction (UPJ), number of stitches (N), anastomosis time per stitch (tn), the average suture time per stitch (T) = (suture time of first stitch (t1) + second stitch (t2) + … + tn)/N, postoperative complications, and surgical outcome. The learning curve was depicted by cumulative sum method (CUSUM) and validated by cumulative method (CUM). Of the 88 cases, 64 cases were included in present study. Median CT was 104 (83-117) min, mean T was 109 ± 17 s. There were ten cases of Clavien-Dindo Grade I complication and two cases of Clavien-Dindo Grade IIIb complication. The median follow-up time was 237 (87-627) days. The learning curve of CT has three stages, with inflection points at 11th and 57th case, and T has two stages, with inflection points at 19th case. There was a statistically significant difference between the console time and length of stay on both sides of the inflection point (P < 0.05), but there was no statistically significant difference in age, gender, etiology, clinical manifestation, surgical outcome, and complication (P > 0.05). For a senior pediatric urologists who is proficient in laparoscopic pyeloplasty, the learning curve of RALP can be divided into three stages, preliminary exploration stage, mastery stage, and proficiency stage. It takes about 11 cases to achieve the mastery stage, and it takes about 57 cases to achieve the proficiency stage. The learning curve focused on the suture technique of the surgeon is divided into two stages, and after a learning period of 19 cases, it will reach the proficiency stage of suturing UPJ.

Predictors of Clinical Failure after Endoscopic Lumbar Spine Surgery During the Initial Learning Curve

OBJECTIVE

This study aims to identify clinical factors that may predict failed endoscopic lumbar spine surgery to guide surgeons with patient selection during the initial learning curve.

METHODS

This is an Australasian prospective analysis of the first 105 patients to undergo lumbar endoscopic spine decompression by 3 surgeons. Modified MacNab outcomes, visual analog scale (VAS) and Oswestry Disability Index (ODI) scores were utilized to evaluate clinical outcomes at 6 months postoperatively. Descriptive statistics and ANOVA t tests were performed to measure statistically significant (P < 0.05) associations between variables using GraphPad Prism v10.

RESULTS

Patients undergoing endoscopic lumbar surgery via an interlaminar or transforaminal approach have overall good/excellent modified MacNab outcomes and a significant reduction in postoperative VAS and ODI scores. Regardless of the anatomic location of disc herniations, good/excellent modified MacNab outcomes and significant reductions in VAS and ODI were reported post-operatively, however, not in patients with calcified disc herniations. Patients with central and foraminal stenosis overall reported poor/fair modified MacNab outcomes, however, there were significant reductions in VAS and ODI scores postoperatively. Patients with subarticular stenosis or an associated spondylolisthesis reported good/excellent modified MacNab outcomes and significant reductions in VAS and ODI scores postoperatively. Patients with disc herniation and concurrent degenerative stenosis had generally poor/fair modified MacNab outcomes.

CONCLUSIONS

The outcomes of endoscopic spine surgery are encouraging with low complication and reoperation rates. However, patients with calcified disc herniations, central canal stenosis, or disc herniation with concurrent degenerative stenosis present challenges during the initial learning curve and may benefit from traditional open or other minimally invasive techniques.

Percutaneous Transforaminal Endoscopic Discectomy Learning Curve: A CuSum Analysis

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To describe the learning curve for percutaneous transforaminal endoscopic discectomy (PTED) and demonstrate its efficacy in treating lumbar disc herniation.

SUMMARY OF BACKGROUND DATA

The learning curve for PTED has not yet been standardized in the literature.

PATIENTS AND METHODS

Consecutive patients who underwent lumbar PTED by a single surgeon between December 2020 and 2022 were included. Cumulative sum analysis was applied to operative and fluoroscopy time to assess the learning curve. Inflection points were used to divide cases into early and late phases. The 2 phases were analyzed for differences in operative and fluoroscopy time, length of stay, complications, and patient-reported outcome measures (PROMs). Patient characteristics and operative levels were also compared. PROMs entailed the Oswestry Disability Index, Patient-Reported Outcomes Measurement Information System, Visual Analog Scale Back/Leg, and 12-item Short Form Survey at preoperative, early postoperative (<6 mo), and late postoperative (≥6 mo) time points. PROMs between PTED cases and a comparable cohort of tubular microdiscectomy cases, performed by the same surgeon, were compared.

RESULTS

Fifty-five patients were included. Cumulative sum analysis indicated that both operative and fluoroscopy time diminished rapidly after case 31, suggesting a learning curve of 31 cases (early phase: n = 31; late phase: n = 24). Late-phase cases exhibited significantly lower operative times (85.7 vs . 62.2 min, P = 0.001) and fluoroscopy times (131.0 vs . 97.2 s, P = 0.001) compared with the early-phase cases. Both early and late-phase cases showed significant improvement in all PROMs. There were no differences in PROMs between the patients who underwent PTED and tubular microdiscectomy.

CONCLUSION

The PTED learning curve was found to be 31 cases and did not impact PROMs or complication rates. Although this learning curve reflects the experiences of a single surgeon and may not be broadly applicable, PTED can serve as an effective modality for the treatment of lumbar disc herniation.

Reducing the learning curve of interlaminar full-endoscopic discectomy: mushroom model-simulation training

PURPOSE

To describe a cheap simulation model used to reduce the learning curve of the interlaminar full-endoscopic discectomy in a pilot study.

INTRODUCTION

The steep and difficult learning curve remain one of the main obstacles against the widespread diffusion of interlaminar full endoscopic lumbar discectomy (ILFED). One solution to overcome this learning curve is training with deliberate practice. As realistic models are relatively expensive and cadaver workshops not readily available, we developed a simple and cheap model to train the key steps of the procedure.

METHODS

A simple and cheap model were designed. It consists of a king oyster mushroom stalk, a glove finger, a sponge and cotton wool. In order to fix the model to the table and to simulate the level of the patient's skin whereupon the hand of the surgeon relies, a wooden holding device was also used. As the purpose of this pilot study was to evaluate the model as a stimulator, it was tested during an advanced endoscopic training course.

RESULTS

A step-by-step learning method with key steps was used by participants attending an advanced ILFED training on expensive realistic models. The model was considered as comparable and enough realistic to train key steps in order to reduce the learning curve and training costs.

CONCLUSION

We present an affordable, simple and reproducible training model, which allows for deliberate practice of the key steps of the ILFED procedure. The model may be used by surgeons starting with spinal endoscopy.

Minimally invasive endoscopy in spine surgery: where are we now?

INTRODUCTION

Endoscopic spine surgery (ESS) is a minimally invasive surgical technique that offers comparable efficacy and safety with less collateral damage compared to conventional surgery. To achieve clinical success, it is imperative to stay abreast of technological advancements, modern surgical instruments and technique, and updated evidence.

PURPOSES

To provide a comprehensive review and updates of ESS including the nomenclature, technical evolution, bibliometric analysis of evidence, recent changes in the spine communities, the prevailing of biportal endoscopy, and the future of endoscopic spine surgery.

METHODS

We conducted a comprehensive review of the literature on ESS for the mentioned topics from January 1989 to November 2022. Three major electronic databases were searched, including MEDLINE, Scopus, and Embase. Covidence Systematic Review was used to organize the eligible records. Two independent reviewers screened the articles for relevance.

RESULTS

In total, 312 articles were finally included for review. We found various use of nomenclatures in the field of ESS publication. To address this issue, we proposed the use of distinct terms to describe the biportal and uniportal techniques, as well as their specific approaches. In the realm of technical advancement, ESS has rapidly evolved from addressing disc herniation and spinal stenosis to encompassing endoscopic fusion, along with technological innovations such as navigation, robotics, and augmented reality. According to bibliometric analysis, China, South Korea, and the USA have accounted for almost three-quarters of total publications. The studies of the biportal endoscopy are becoming increasingly popular in South Korea where the top ten most-cited articles have been published. The biportal endoscopy technique is relatively simple to adopt, as it relies on a more familiar approach, requires less expensive instruments, has a shorter learning curve, and is also well-suited for interbody fusion. The uniportal approach provided the smallest area of soft tissue dissection. While robotics and augmented reality in ESS are not widely embraced, the use of navigation in ESS is expected to become more streamlined, particularly with the emergence of recent electromagnetic-based navigation technologies.

CONCLUSIONS

In this paper, we provide a comprehensive overview of the evolution of ESS, as well as an updated summary of current trends in the field, including the biportal and uniportal approaches. Additionally, we summarize the nomenclature used in ESS, present a bibliometric analysis of the field, and discuss future directions for the advancement of the field.

2nd and 3rd generation full endoscopic lumbar spine surgery: clinical safety and learning curve

AIM

2nd and 3rd generation endoscopic spine surgery techniques offer visualisation of familiar inter-laminar anatomy to spinal surgeons. We have prospectively evaluated the clinical outcome, complications and learning curve associated with these techniques in patients with lumbar spine radiculopathy.

METHODS

This is a prospective study of 50 consecutive patients with radicular pain from disc herniation and/or lateral recess stenosis. In 6 patients, endoscopy couldn't be done. Operating times, PROM's (VAS, ODI and EQ-5D scores) and complication rates of 44 patients were evaluated after mean FU of 52 months (range 39-65). MRI was used to divide these into protrusions (n = 19), extrusions (n = 17) and lateral recess stenosis (n = 8). Evidence about the learning curve was gathered by curvilinear regression analyses.

RESULTS

Using a composite clinical success criterion, 95% patients had a successful outcome, with no major complications. ODI, VAS and EQ-5D scores had a statistically significant improvement and achieved MCID. Revision discectomy rate was only 4.5% (n = 2). MRI based grouping, case sequence and degree of difficulty influenced the duration of surgery and a learning curve was found for protrusions and lateral recess decompressions, but not for extrusions. A learning curve effect was also observed with respect to the ODI.

CONCLUSIONS

Although anatomy visualised in 2nd and 3rd generation endoscopy is familiar to spinal surgeons, our learning curve experience suggests a careful and MRI pathology based take up of this technique in clinical practice, despite its clinical safety in our series.

LEVEL OF EVIDENCE

Level 3, prospective cohort study.

Is navigation beneficial for transforaminal endoscopic lumbar foraminotomy? A preliminary comparison study with fluoroscopic guidance

PURPOSE

The primary purpose of this study was to determine radiation exposure of the surgeon during transforaminal endoscopic lumbar foraminotomy (TELF). Secondary purpose of this study was to compare clinical and radiologic outcomes between TELF under C-arm fluoroscopic guidance (C-TELF) and O-arm navigation-guided TELF (O-TELF).

METHODS

The author reviewed patients' medical records who underwent TELF at our institute from June 2015 to November 2022. A total of 40 patients were included (18 patients with C-TELF and 22 with O-TELF). Basic demographic data were collected. Preoperative/postoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) were recorded at the outpatient clinic. Radiologic features were compared on X-rays at each follow-up. The degree of foraminal expansion was measured/compared through MRI. In the C-TELF group, the amount of exposure was calculated with a dosimeter.

RESULTS

Average surgeon's effective dose in the C-TELF group was 0.036 mSv. In the case of the O-TELF group, there was no radiation exposure during operation. However, the operation time in the O-TELF group was about 37 min longer than that in the C-TELF group. There were significant improvements in VAS/ODI after operation in both groups. Complications were identified in three patients.

CONCLUSION

O-TELF showed similarly favorable clinical and radiologic outcomes to C-TELF in lumbar foraminal stenosis, including complication rate. Compared to C-TELF, O-TELF has an advantage of not wearing a lead apron since the operator is not exposed to radiation. However, the operation time was longer with O-TELF due to O-arm setting time. Because there are pros and cons, the choice of surgical method depends on the surgeon's preference.

Efficacy of Transforaminal Endoscopic Lumbar Discectomy in Elderly Patients Over 65 Years of Age Compared to Young Adults

OBJECTIVE

Spine surgery rates are increasing in the elderly population due to social aging, and it is known that prognoses related to surgery are worse for the elderly compared to younger individuals. However, minimally invasive surgery, such as full endoscopic surgery, is considered safe with low complication rates due to minimal damage to surrounding tissues. In this study, we compared outcomes of transforaminal endoscopic lumbar discectomy (TELD) in elderly and younger patients with disc herniation in the lumbosacral region.

METHODS

We retrospectively analyzed the data of 249 patients who underwent TELD at a single center between January 2016 to December 2019, with a minimum follow-up of 3 years. Patients were allocated to 2 groups: a young group aged ≤ 65 years (n = 202) or an elderly group aged > 65 years (n = 47). We evaluated baseline characteristics, clinical outcomes, surgery-related outcomes, radiological outcomes, perioperative complications, and adverse events during the 3-year follow-up period.

RESULTS

Baseline characteristics, including age, general condition based on American Society of Anesthesiologist physical status classification grade, age-Charlson Comorbidity Index, and disc degeneration, were worse in elderly group (p < 0.001). However, except for leg pain at 4 weeks after surgery, overall outcomes, including pain improvement, radiological change, operation time, blood loss, and hospital stay, were not different between the 2 groups. Furthermore, the rates of perioperative complications (9 patients [4.46%] in the young group and 3 patients [6.38%] in the elderly group, p = 0.578) and adverse events over the 3-year follow-up period (32 patients [15.84%] in the young group and 9 patients [19.15%] in the elderly group, p = 0.582) were comparable in the 2 groups.

CONCLUSION

Our findings suggest that TELD produces similar outcomes in both elderly and younger patients with a herniated disc in the lumbosacral region. TELD can be considered a safe option for appropriately selected elderly patients.

Training to be a spinal endoscopic surgeon: What matters?

Objective

Spinal endoscopic surgery has been promoted rapidly in the past decade, attracting an increasing number of young, dedicated surgeons. However, it has long been denounced for its long learning curve as a factor impeding the development of this state-of-the-art technique. The aim of the present study was to discover what really matters in the educational process of becoming a spinal endoscopic surgeon.

Methods

An online survey consisting of 14 compulsory questions was distributed in April and May 2022 through the First Chinese Spinal Endoscopic Surgeons Skills Competition. Reminders were sent to increase response rates.

Results

Of the 893 emails that were sent, we received 637 responses. A total of 375 (76.7%) surgeons most frequently used endoscopic techniques in their practices. Regardless of their different backgrounds, 284 (75.7%) surgeons thought it would be necessary for a young spinal endoscopic surgeon to perform 300 cases independently in order to become proficient, followed by 500 (n=43, 11.5%), 100 (n=40, 10.7%), and 1,000 (n=8, 2.1%) cases. According to the surgeons, the most difficult aspect of mastering the endoscopic technique is a disparate surgical view (n=255, 68%), followed by adaption to new instruments (n=86, 22.9%) and hand-eye coordination (n=34, 9.1%). The most helpful training method for helping the spinal endoscopic surgeons of younger generations improve is operating on simulation models or cadaver courses (n=216, 57.6%), followed by online or offline theoretical courses (n=67, 17.9%), acquiring opportunities during surgeries (n=51, 13.6%), and frequently participating in surgeries as an assistant (n=41, 10.9%).

Conclusion

From the perspective of surgeons, to be skilled in spinal endoscopic surgery means overcoming a steep learning curve. However, training systems should be given more attention to make them more accessible to younger surgeons so they can work on simulation models or take cadaver courses.

How dimensions can guide surgical planning and training: a systematic review of Kambin's triangle

OBJECTIVE

The authors sought to analyze the current literature to determine dimensional trends across the lumbar levels of Kambin's triangle, clarify the role of imaging techniques for preoperative planning, and understand the effect of inclusion of the superior articular process (SAP). This compiled knowledge of the triangle is needed to perform successful procedures, reduce nerve root injuries, and help guide surgeons in training.

METHODS

The authors performed a search of multiple databases using combinations of keywords: Kambin's triangle, size, measurement, safe triangle, and bony triangle. Articles were included if their main findings included measurement of Kambin's triangle. The PubMed, Scopus, Ovid, Cochrane, Embase, and Medline databases were systematically searched for English-language articles with no time frame restrictions through July 2022.

RESULTS

Eight studies comprising 132 patients or cadavers were included in the study. The mean ± SD age was 66.69 ± 9.6 years, and 53% of patients were male. Overall, the size of Kambin's triangle increased in area moving down vertebral levels, with L5-S1 being the largest (133.59 ± 4.36 mm2). This trend followed a linear regression model when SAP was kept (p = 0.008) and removed (p = 0.003). There was also a considerable increase in the size of Kambin's triangle if the SAP was removed.

CONCLUSIONS

Here, the authors have provided the first reported systematic review of the literature of Kambin's triangle, its measurements at each lumbar level, and key areas of debate related to the definition of the working safe zone. These findings indicate that CT is heavily utilized for imaging of the safe zone, the area of Kambin's triangle tends to increase caudally, and variation exists between patients. Future studies should focus on using advanced imaging techniques for preoperative planning and establishing guidelines for surgeons.

Decompression versus decompression plus fusion for treating degenerative lumbar spinal stenosis: A systematic review and meta-analysis

BACKGROUND

Degenerative lumbar spinal stenosis (DLSS) is a complex clinical syndrome that leads to spinal compression. Decompression with fusion has been the most commonly used surgical procedure for treating DLSS symptoms for many years. However, the exact role of fusion and its effectiveness in DLSS therapy has recently been debated.

OBJECTIVE

The main purpose of this study was to compare the efficacy and safety of decompression alone and decompression plus fusion in the treatment of DLSS with or without spondylolisthesis.

STUDY DESIGN

A systematic review and meta-analysis of the therapeutic effects of decompression for DLSS with or without the combination of fusion.

METHODS

A literature search in five relevant databases, including Web of Science, PubMed, Embase, Medline, and Cochrane Library was performed from the inception of the database to March 2022. Only randomized controlled trials (RCTs) assessing the comparison between decompression and decompression plus fusion for DLSS were included.

RESULTS

A total of seven studies, 894 patients were analyzed in this meta-analysis. Among these, 443 patients were included in the decompression plus fusion group while 451 patients were included in the decompression alone group. Pooled analysis showed that the combination of decompression with fusion had no superior benefits to decompression alone in terms of Oswestry Disability Index (ODI) score in the first 2 years and long-term follow-up after surgery, also no significant difference in the improvement of back and leg pain was found between two groups. Adding fusion to decompression was associated with a longer operation time, higher complication rate, more blood loss, and extended hospital stay. Furthermore, there was no difference in reoperation rates and patients' satisfaction between the two groups at the last follow-up.

CONCLUSION

Decompression plus fusion may not be associated with a better clinical outcome in ODI scores and back or leg pain improvement but with a longer duration of operation time, extended hospital stay, and more blood loss.

Percutaneous endoscopic lumbar discectomy via the medial foraminal and interlaminar approaches: A comparative study with 2-year follow-up

OBJECTIVE

The purpose of this study was to analyze the clinical effect of percutaneous endoscopic medial foraminal discectomy (PEMFD) in the treatment of lumbar disc herniation (LDH).

METHODS

We retrospectively examined and compared clinical data from 39 single-level LDH patients who underwent PEID and 47 who underwent PEMFD. All the patients were diagnosed with single-level LDH and were treated in Xuzhou Central Hospital for single-segmental lumbar disc herniation between June 2017 and December 2019. Collect and count surgical-related indicators, intraoperative bleeding volume and 24-hour postoperative drainage volume, lower extremity numbness Visual Analogue Scale (VAS), the pain VAS and lumbar Oswestry Disability Index (ODI) scores.

RESULTS

Intraoperative bleeding volume and 24-hour postoperative drainage volume were significantly lower in the PEMFD group (p < 0.05). Operation time and length of hospital stay did not significantly differ between the groups. Transient spinal cord injury and surgical site infection did not occur. Recurrence occurred in two patients in each group. Repeat surgery in these patients demonstrated remarkable epidural scarring in the PEID group patients; no scarring was evident in the PEMFD group patients. The numbness VAS score 72 h after surgery and the pain VAS and ODI scores 1 month after surgery significantly differed between groups; however, pain VAS and ODI scores 6, 12, and 24 months after surgery did not. At last follow-up, the modified MacNab criteria outcome did not significantly differ between the groups.

CONCLUSION

PEMFD and PEID have similar short- and medium-term outcomes. However, PEMFD has several advantages: simplicity, lower bleeding volume, and preservation of the LF.

The clinical efficacy of biportal endoscopy is comparable to that of uniportal endoscopy via the interlaminar approach for the treatment of L5/S1 lumbar disc herniation

Objective

To compare the clinical outcomes of unilateral biportal endoscopy/biportal endoscopic spinal surgery (UBE/BESS) via the posterior approach with those of interlaminar endoscopic lumbar discectomy (IELD) for the treatment of L5/S1 lumbar disc herniation.

Methods

We collected the clinical data of patients with L5/S1 lumbar disc herniation who had undergone endoscopic surgery at our center from January 2020 to July 2021, and 92 patients were included. They were divided into UBE/BESS (n = 42) and IELD (n = 50) groups. The incision length, operative time (overall operative, extracanal operative, and intracanal decompression times), intraoperative radiation exposure dose, changes in hemoglobin before and after surgery, postoperative hospital stay, visual analog scale (VAS) score for low back pain and leg, and Oswestry disability index (ODI) were statistically analyzed.

Results

One case incurred dural tear in the UBE/BESS group, and one case developed recurrence in the IELD group. Postoperatively, the VAS score and ODI index decreased significantly in both groups (P < 0.01). VAS and ODI scores (preoperative as well as 3 days, 3 months, 6 months, and 12 months after surgery), the overall operative time, and postoperative hospital stay were not significantly different between the two groups (P > 0.05). No statistical difference in intraoperative radiation exposure dose was noted between the two groups (P > 0.05). The surgical incision length was greater in the UBE/BESS group (P < 0.01), and pre- and postoperative hemoglobin changes were more pronounced in the UBE/BESS group (P < 0.01). The UBE/BESS group had a longer extracanal operative time and shorter intracanal decompression time (P < 0.01).

Conclusions

The clinical efficacy of UBE/BESS for L5/S1 lumbar disc herniation is comparable to that of IELD. Intraoperative radiation exposure doses were similar in both techniques. UBE/BESS required more time to identify tissue structures and a larger working space when operating outside the spinal canal; however, the efficiency of nucleus pulposus removal and nerve root release inside the spinal canal superseded that in IELD. Furthermore, the surgical incision in the UBE/BESS technique was longer, with greater actual blood loss during surgery, thus rendering UBE/BESS inferior to the IELD technique in terms of surgical trauma. Nonetheless, no significant difference was noted between the two techniques in the postoperative recovery time of patients.

Surgeons Learning Curve of Transforaminal Endoscopic Discectomy for Sciatica

OBJECTIVE

Full-endoscopic spine surgery is gaining interest as a less-invasive alternative to treat sciatica caused by a lumbar disc herniation. Concerns, however, exist with the learning curve as percutaneous transforaminal endoscopic discectomy (PTED) appears to be more difficult to be performed compared to other techniques. In this study, the clinical outcomes during and after the learning curve are presented of 3 surgeons naïve to PTED.

METHODS

In the first phase of a randomized controlled, noninferiority trial comparing PTED with microdiscectomy, 3 surgeons were trained in the PTED-procedure by a senior surgeon. After performing up to 20 cases under supervision, they started performing PTED on their own. Results of the early cases were compared to the later cases (>20). Furthermore, complications and reoperations were compared. Finally, differences in clinical outcomes between surgeons were compared.

RESULTS

At 12 months of follow-up, 87% of the patients had follow-up data available. In general, there were no significant differences in patient-reported outcomes between the early and later PTED cases. Furthermore, outcomes of the early PTED cases were comparable to the outcomes of microdiscectomy, while the later PTED cases had small, but more favorable outcomes compared to microdiscectomy. Two learning curve surgeons had substantially higher rates of reoperations within 1 year, compared to the senior surgeon or the microdiscectomy group. Duration of surgery was also longer for all learning curve surgeons. Finally, when comparing clinical outcomes of patients undergoing PTED versus microdiscectomy, there appears to be some statistically significant differences in outcomes compared between the senior and 3 learning curve surgeons.

CONCLUSION

PTED appears to be safe to be adopted by surgeons naïve to the procedure when they are initially supervised by an experienced senior surgeon. Duration of surgery and risk of repeated surgery are increased during the learning curve, but patient-reported outcomes of the early PTED cases are similar to the outcomes of later PTED cases, and similar to the outcomes of microdiscectomy cases. This study underlines the need for an experienced mentor for surgeons to safely adopt PTED.

Learning Curve and Complications of Unilateral Biportal Endoscopy: Cumulative Sum and Risk-Adjusted Cumulative Sum Analysis

OBJECTIVE

The purpose of this study was to investigate the learning curve and complications of unilateral biportal endoscopy (UBE) in the treatment of lumbar disc herniation (LDH) and lumbar spinal stenosis (LSS).

METHODS

This was a retrospective cohort analysis of 197 consecutive patients who received UBE unilateral laminotomy bilateral decompression (UBE-ULBD) or lumbar discectomy (UBE-LD) surgery, including 107 males and 90 females with an average age of 64.83 ± 14.29 years. Cumulative sum (CUSUM) and risk-adjusted cumulative sum analysis (RA-CUSUM) were used to evaluate the learning curve, with the occurrence of complications defined as surgical failure, and variables of different phase of the learning curve were compared.

RESULTS

The cutoff point of learning curve of UBE surgery was 54 cases according to CUSUM analysis. The learning curve of UBE-ULBD and UBE-LD were divided into 3 phases. The first cutoff points were 31 and 12 cases, and the second cutoff point were 67 and 32 cases respectively. With the progress of the learning curve, the operation time and postoperative hospital stays decreased. The visual analogue scale and Oswestry Disability Index at the last follow-up were significantly lower than that before surgery. The incidence of surgical failure was 6.11% and began to decrease after the 89th case based on RA-CUSUM analysis. The surgical failure rate decreased from 10.11% to 2.78 after the 89th case with significant different.

CONCLUSION

UBE surgery is effective in the treatment of LDH and LSS with low incidence of complications. But a learning curve of at least 54 cases still required for mastering UBE surgery.

Assessing the Learning Process of Transforaminal Endoscopic Discectomy for Sciatica

OBJECTIVE

Percutaneous transforaminal endoscopic discectomy (PTED) is gaining popularity by both surgeons and patients as a less invasive treatment option for sciatica. Concerns, however, exist for its learning curve. No previous study has assessed the learning process of PTED. Hereby we present the learning process of 3 surgeons learning PTED.

METHODS

This analysis was conducted alongside a multicenter randomized controlled trial. After attending a cadaveric workshop, 3 spine-dedicated surgeons started performing PTED, initially under the supervision of a senior surgeon. After each 5 cases, and up to case 20, the learning process was evaluated using the validated questionnaires (objective structured assessment of technical skills [OSATS], global operative assessment of laparoscopic skills [GOALS]) and a 10-step checklist specifically developed for PTED.

RESULTS

In total, 3 learning curve surgeons performed a total of 161 cases. Based on self-assessment, surgeons improved mostly in the domains "time and motion," "respect for tissue," and "knowledge and handling of instruments." Learning curve surgeons were more able to detect differences in performances on the OSATS than the senior surgeon. Based on the GOALS, the biggest improvements could be seen in "depth-perception" and "autonomy." Based on the 10-item specific checklist, all surgeons performed all 10 steps by case 10, while only 1 surgeon performed all steps adequately by case 15.

CONCLUSION

Based on these study results, PTED appears to be successfully adopted stepwise by 3 spine-dedicated surgeons. From 15 cases on, most steps are performed adequately. However, more cases might be necessary to achieve good clinical results. Validated tools are needed to determine the cutoff when a surgeon should be able to perform PTED independently.

Lateral Lumbar Interbody Fusion: Single Surgeon Learning Curve

OBJECTIVE

To characterize lateral lumbar interbody fusion surgical learning curve and investigate changes in perioperative and postoperative clinical parameters associated with increased operative experience.

METHODS

In a case series, surgical learning curve was defined using 3-parameter asymptotic regression and piecewise linear regression, yielding learning phase (patients 1-53) and proficient phase (patients 54-179) cohorts. Using a 5-point grading scale, ipsilateral iliopsoas (hip-flexion) and quadriceps (knee-extension) muscle strength and thigh and groin sensory disturbances were compared for differences preoperatively versus postoperatively using χ² test. Patient-reported outcome measures were collected preoperatively and postoperatively and compared between cohorts with unpaired t test.

RESULTS

The proficient phase cohort demonstrated significantly reduced operative time, estimated blood loss, postoperative length of stay, and narcotic consumption on postoperative days 0 and 1. The proficient phase cohort displayed decreased disability at 6 weeks and 6 months and demonstrated significant improvement at all time points for disability, pain, and physical function except for 6 weeks and 2 years for physical function, whereas the learning phase cohort demonstrated improvement in disability beginning at 6 months, leg pain at all time points, and back pain through 6 months. Ipsilateral groin and thigh sensory disturbances and iliopsoas and quadriceps weakness improved with increasing operative experience.

CONCLUSIONS

The proficient phase cohort demonstrated significantly improved perioperative profile, reduced complication rate, and reduced rates of iliopsoas and quadriceps weakness. While the proficient phase cohort demonstrated earlier improvement in disability and physical function scores compared with the learning phase cohort, 2-year outcome measures did not differ. Long-term clinical outcomes suggest that patient safety and quality of life are not compromised during the learning phase, but patients may be particularly susceptible to femoral nerve injury early in a surgeon's practice.

The Learning Curve of Unilateral Biportal Endoscopic (UBE) Spinal Surgery by CUSUM Analysis

Objective

To assess the learning curve of the unilateral biportal endoscopic (UBE) technique for the treatment of single-level lumbar disc herniation by cumulative summation (CUSUM) method analysis.

Methods

A retrospective analysis was conducted to assess 97 patients' general condition, operation time, complications, and curative effect of single segmental UBE surgery performed by a spinal surgeon in his early stage of this technique. The learning curve of operation time was studied using a CUSUM method, and the cut-off point of the learning curve was obtained.

Results

The operation time was 30 – 241(97.9 ± 34.7) min. The visual analog scale score of lower limb pain decreased from 5.75 ± 0.81 before the operation to 0.39 ± 0.28 at the last follow-up (P &lt; 0.05). The Oswestry disability index score decreased from 66.48 ± 4.43 before the operation to 14.57 ± 3.99 at the last follow-up (P &lt; 0.05). The CUSUM assessment of operation time revealed the learning curve was the highest in 24 cases. In the learning stage (1–24 cases), the operation time was 120.3 ± 43.8 min. In the skilled stage (25–97 cases), the operation time was 90.5 ± 27.8 min.

Conclusions

About 24 cases of single segmental UBE operation are needed to master the UBE technique.

Transforaminal Endoscopic Lumbar Discectomy with versus without Platelet-Rich Plasma Injection for Lumbar Disc Herniation: A Prospective Cohort Study

Objective

Transforaminal endoscopic lumbar discectomy (TELD) is an effective treatment for patients with lumbar disc herniation (LDH) with failure of conservative treatment. However, defects in the annulus fibrosus after TELD usually lead to a recurrence of LDH. Platelet-rich plasma (PRP) injection has shown promising potential for the repair of injured tissues. The combination of TELD and PRP injection has rarely been reported. Hence, this study aimed to evaluate the effectiveness, disc remodeling, and recurrence rate of LDH in TELD with or without PRP in LDH treatment.

Methods

A total of 108 consecutive patients who underwent TELD were prospectively registered between July 2018 and December 2019 (https://clinicaltrials.gov/ct2/show/ChiCTR1800017228). Fifty-one and fifty-seven patients underwent TELD with PRP injections and TELD only, respectively. The visual analog scale (VAS) score for back and leg pain, Oswestry Disability Index (ODI), and MacNab criteria were evaluated, and perioperative complications were documented. The disc protrusion, spinal cross-sectional area (SCSA), and disc height were measured on MRI and evaluated preoperatively, postoperatively, and at regular follow-up.

Results

All patients were followed up. Clinical improvement was noted in both groups. There were statistical differences in the VAS scores of back and leg pain and ODI between the two groups at 3 months, 6 months, and 1 year follow-up (P < 0.05); the improvement in the PRP group was significant. The disc protrusion and SCSA on MRI in the PRP group showed better improvement, with lower recurrence rate, than that in the control group at the final follow-up (P < 0.05). No adverse events were reported in our study following PRP injection.

Conclusion

Our study showed that TELD with PRP injection was a safe and effective treatment for patients with LDH in the medium and long-term follow-up. PRP injection was beneficial for disc remodeling after endoscopic discectomy and decreased the recurrence of LDH.