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ORIGINAL ARTICLE: MINIMALLY INVASIVE SURGERY • Coluna/Columna 23 (3) • 2024 • https://doi.org/10.1590/S1808-185120242303281365 linkcopy

Open-access PERCEPTION OF THE LEARNING CURVE FOR ENDOSCOPIC SPINE PROCEDURES, A SURVEY OF SPINAL SURGEONS IN LATAM

PERCEPÇÃO DA CURVA DE APRENDIZADO PARA PROCEDIMENTOS ENDOSCÓPICOS DE COLUNA, UMA PESQUISA COM CIRURGIÕES DE COLUNA DA LATAM

PERCEPCIÓN DE LA CURVA DE APRENDIZAJE PARA PROCEDIMIENTOS ENDOSCÓPICOS DE COLUMNA, UNA ENCUESTA A CIRUJANOS DE COLUMNA DE LATAM

AuthorshipSCIMAGO INSTITUTIONS RANKINGS

    ABSTRACT

    Objective:  Full endoscopic uniportal spine procedures offer the advantages of minimally invasive surgery. One of the reasons its worldwide acceptance hasn’t been as expected is because of the perception of a long learning curve. This multicentric survey-based study is designed to identify the perception of the learning curve needed for full endoscopic spine procedures. It was applied to spine surgeons of Latin America and looked to assess the different variables that influence the perception of a learning curve.

    Methods:  A 23-item questionnaire focusing on demographics, experience, and education regarding full endoscopic spine surgery was sent to all registered surgeons in the AO Spine LATAM (a specialty group within the AO Foundation) database. Data analysis was done based on the answers provided.

    Results:  296 members (out of 1164 AOSpine active members) answered the survey. 54.73% of the responders think that the best way to learn the technique is a combination of an Observership with an expert surgeon, cadaveric or model workshop, and operating with an expert. Most of the responders agree that 26 is the average of surgeries needed to master either the interlaminar approach or the transforaminal approach.

    Conclusions:  The learning curve perceived by spine surgeons is below what is reported in the literature for both interlaminar and transforaminal approaches. Endolif was found to be the least performed procedure. Level of Evidence I; Local and current random sample surveys (or censuses).

    Keywords: Minimally Invasive Surgical Procedures; Learning curve; Perception; Endoscopy

    RESUMO

    Objetivo:  O procedimento endoscópico uniportal completo da coluna oferece toda a vantagem da cirurgia minimamente invasiva. Pensa-se que uma das razões pelas quais a sua aceitação mundial não tem sido a esperada é a percepção de uma longa curva de aprendizagem. Este é um desenho de estudo multicêntrico baseado em pesquisa para identificar a percepção da curva de aprendizado necessária para procedimentos endoscópicos completos de coluna, aplicado a cirurgiões de coluna da América Latina, buscando avaliar as diferentes variáveis que influenciam a percepção da curva de aprendizado.

    Métodos:  Um questionário de 23 itens com foco em dados demográficos, experiência e educação em relação à cirurgia endoscópica completa da coluna foi enviado a todos os cirurgiões registrados no banco de dados AO Spine LATAM (um grupo especializado dentro da Fundação AO). A análise dos dados foi feita com base nas respostas fornecidas.

    Resultados:  296 membros (de 1.164 membros ativos da AOSpine) responderam à pesquisa. 54,73% dos respondentes pensam que a melhor forma de aprender a técnica é combinar um Observership com um cirurgião especialista, oficina cadavérica ou de modelos, e operar com um especialista. A maioria dos respondentes concorda que 26 é a média de cirurgias necessárias para dominar a abordagem interlaminar ou transforaminal.

    Conclusões:  A curva de aprendizado percebida está abaixo daquela relatada na literatura tanto para a abordagem interlaminar quanto para a transforaminal. O Endolif foi o procedimento menos realizado. Nivel de evidencia I; Pesquisas de Amostras Aleatórias (ou censos) Locais e Atuais.

    Descritores: Procedimentos Cirúrgicos Minimamente Invasivos; Curva de aprendizado; Percepção; Endoscopia

    RESUMEN

    Objetivo:  El procedimiento uniportal endoscópico completo de columna ofrece todas las ventajas de la cirugía mínimamente invasiva. Se piensa que una de las razones por las que su aceptación mundial no ha sido la esperada sea por la percepción de una larga curva de aprendizaje. Se trata de un diseño de estudio multicéntrico basado en encuestas para identificar la percepción de la curva de aprendizaje necesaria para procedimientos endoscópicos de columna, aplicado a cirujanos de columna de América Latina, buscando evaluar las diferentes variables que influyen en la percepción de la curva de aprendizaje.

    Métodos:  Se envió un cuestionario de 23 ítems centrado en la demografía, la experiencia y la educación sobre la cirugía endoscópica a todos los cirujanos registrados en la base de datos de AO Spine LATAM (un grupo de especialidad dentro de la Fundación AO). El análisis de se realizó con base a las respuestas proporcionadas.

    Resultados:  296 miembros (de 1164 miembros activos de AOSpine) respondieron la encuesta. El 54,73% de los encuestados piensa que la mejor manera de aprender la técnica es una combinación de Observership con un cirujano experto, taller de cadáveres o modelos, y operar con un experto. La mayoría de los encuestados coinciden en que 26 es el promedio de cirugías necesarias para dominar el abordaje interlaminar o el abordaje transforaminal.

    Conclusiones:  La curva de aprendizaje percibida por los cirujanos de columna, está por debajo de lo reportado en la literatura, tanto para interlaminar como transforaminal. Endolif resultó el procedimiento menos realizado. Nivel de Evidencia I; Investigaciones de Muestras Aleatorias (o censos) Locales y Actuales.

    Descriptores: Procedimientos Quirúrgicos Mínimamente Invasivos; Curva de aprendizaje; Percepción; Endoscopía

    INTRODUCTION

    Full endoscopic spine surgery has become a very attractive surgical technique for spine surgeons worldwide, as it represents the minimally invasive surgery concept in its full meaning. When learning a new procedure, performance tends to improve with experience. Measures of learning related to a surgical technique fall into two categories: measures of surgical process and measures of patient outcome.1 Surgical process measures include operative factors such as operative time and blood loss. Patient outcomes include postoperative factors such as analgesia requirement, transfusion requirement, length of stay in intensive care, length of stay in hospital, morbidity, and mortality rates. Process outcomes are generally easier to analyze and, therefore, more commonly used. However, they are only indirectly related to patient outcomes.1A learning curve shows the rate of improvement in performing a task as a function of time (or number of repetitions of the task at hand).2-4 The learning curve in minimally invasive surgery (MIS) is multifactorial and controversial.5-9

    The major concerns regarding full endoscopic surgery include a steep learning curve, fear of failure, complications, and recurrence after surgery, particularly if the surgeon is in his junior stage. There are no guidelines or gold standards on how to learn full endoscopic surgery.2,3 Open midline lumbar discectomy is a procedure familiar to most spine surgeons and results in good outcomes. However, open surgery often requires muscle retraction, dural sac, and nerve retraction. This can cause instability and scarring of the epidural space, which can become clinically symptomatic in 10% of patients or more.4

    A steep learning curve is often considered a complicated and slow process since it is a “steep climb upward” that requires much effort. However, a steep learning curve is a good thing, considering that with a few procedures, the surgeon or learner can acquire enough experience and rapidly master the technique.1,10

    The objective of this study is to comprehend, based on the experience of Latin American spine surgeons, the best way to start the full endoscopic surgery learning curve.

    MATERIALS AND METHOD

    The authors created and consented to a 23-item questionnaire on demographics, experience, and education regarding full endoscopic spine surgery. The questionnaire was sent to all AO Spine LATAM database registered spine surgeons. It is divided into three sections, and the surgeon’s background formation, experience, and perspective toward full endoscopic spine surgery and its modalities are analyzed.

    The AOSpine database includes surgeons from their first years of practice to experts and seniors and covers all countries in Latin America.

    This study was carried out by AOspine Latam and supported by the MISS Study Group.

    The survey, in Spanish and Portuguese, was sent electronically to all active members, 1164 spine surgeons, in March 2022.

    Ethical registration was not required due to the anonymous nature of the survey conducted with AO Spine LATAM members. (Appendix 1)

    Statistical Analysis

    According to the different factors under study, statistical analysis of the survey responses was done using the non-parametric Mann-Whitney or Kruskal-Wallis tests, as appropriate. The use of non-parametric tests is due to the breach of the necessary assumptions to carry out parametric tests. P values < 0.05 were considered statistically significant. The analyses were carried out with the Minitab 19 software. On the other hand, the graphs were made with RStudio, version 1.4.1106.

    Continuous variables were summarized by their mean and Standard Deviation (SD). Categorical variables were summarized as absolute numbers and as a percentage of the N = 296 total subjects.

    Ethical registration was not required due to the nature of the survey, which collected information anonymously from members of AO Spine LATAM.

    RESULTS

    Out of the 296 participants, the mean age was 45, with an average of 14 years of experience, as shown in Table 1. We found a 60-vs 40 percent of endoscopic practitioner vs nonpractitioner relation among surveyed surgeons.

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    Table 1
    Continuous variables description. Its median describes each of the continuous variables of the sample, the Standard Error of the Median (SEM), the minimum value (Min), the first quartile (Q1), the median, the third quartile (Q3), and the maximum value (Max). Those values under Q1 represent 25% of the data, while those less than Q3 represent 75% of the values. N = Number of individuals answered.

    The countries with the highest response were Brazil and Mexico, with 103 and 68, respectively; Central America was the region with fewer responders. Spine surgeons answered mainly; 75% and 65% of the surveyed were Orthopedic surgeons vs. 35% Neurosurgeons, as shown in Table 2.

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    Table 2
    Categorical variables description. Each of the categorical variables of the sample is described by the number of individuals who choose the different options.

    The highest percentage of responders were junior surgeons (less than five years of professional practice as spine surgeon) with 27.7% of responders, followed by 25.68% of sub-senior surgeons (10-15 years of professional practice as spine surgeon), 23.65% of senior surgeons (more than 15 years of professional practice as spine surgeon) and for last 22.97 middle experienced surgeons (5-10 years of professional practice as spine surgeon) as shown on Table 3.

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    Table 3
    Categorical variables description. Each of the categorical variables of the sample is described by the number of individuals who choose the different options.

    75% of the responders (222) were spine surgeons, followed by 16.55% of Orthopaedics surgeons or Neurosurgeons with no further spine training, with a professional practice composed of public and private medicine in its majority (61.5%).

    The majority of the responders (70%) have had contact with full endoscopic spine surgery either as an observer or with workshops and feel more comfortable with both transforaminal (62%) and interlaminar (62%) discectomy and less comfortable with endoscopic fusion procedures (5%). Even though most of them (69%) answered that they do not have an expert to help them with their learning curve, they believe that the best way to learn is through a sum of observership with an expert, cadaveric or model workshop, and having the support of an expert during the beginning of the learning curve. The least useful was the expert Observership alone.

    When asked what the main limitation to starting endoscopic procedures or techniques (more than one option possible) was, 63% answered a lack of training, followed by a lack of financial resources. The long learning curve was a concern for 20%, and only 6% considered that the technique was not superior, hence worth the migration to endoscopic techniques, as shown in Table 4.

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    Table 4
    Statistical tests to compare the different variables. The table shows the comparisons between the different variables. Non-parametric tests (Kruskal-Wallis, Mann-Whitney) were performed. P-values less than 0.05 were considered statistically significant and highlighted in red. Refs: DF: Degrees of freedom; W-value: Mann-Whitney statistic; H-statistic: Kruskal Wallis statistic.

    Responders perceived that 26-27 full endoscopic spine surgeries are needed to master either the transforaminal or interlaminar endoscopic approaches. (Table 1)

    DISCUSSION

    This survey addressed spine surgeons from Mexico, Central America, and South America with diverse cultural and professional backgrounds, training levels, and attitudes toward full endoscopic spine surgery.

    Our survey had a fairly good number of respondents (n=296) from most of our region’s countries, giving our study an acceptable regional representative value.

    Full endoscopic spine surgery has been around for a while. Still, it hasn’t even been accepted by the spine surgery community, and one of the reasons is the long, challenging, and even dangerous learning curve surgeons imagine it has. The literature varies widely, from Morgenstern’s paper, which says that an average of 70 cases are needed to master the transforaminal technique, to Hsien-Ta Hsu et al.4, who says that around the 10th case, the surgeon learns how to do full transforaminal endoscopic spine surgery, guiding us to believe that a bigger, multicentric and focused study based on education, experience, and evidence was needed.

    Our study considers the opinions and experiences of a diverse group of spine surgeons from different regions in Latin America to provide an objective pathway to achieving an efficient learning curve in full endoscopic spine surgery.

    So far, the learning curve for Endoscopic Interlaminar Lumbar Discectomy (EILD) is longer than for Open Lumbar Microdiscectomy (OLM).2 However, the learning curve of PEILD was not as difficult as those of other minimally invasive spine surgeries, and the operation time of EILD was significantly shorter than that of OLM. Moreover, the safety and efficacy of EILD were similar to OLM, with comparable failure, complication, and recurrence rates.2

    The majority of our responders (75%) are spine surgeons (orthopedic surgeons or neurosurgeons with further training in spine pathologies) with some training or exposure to video-assisted surgery and fluoroscopic procedures, which are thought to give the surgeon an edge in anatomic orientation and surgical equipment handling, making the learning curve somewhat more friendly.

    59% of the Respondents haven’t done a full endoscopic spine procedure. Based on our results, we think this is because, even though most have been exposed to observerships with experts and cadaveric or model workshops, 69% don’t have an expert available to help them at the beginning of their learning curve.

    A higher percentage of responders answered having prior experience with endoscopic or arthroscopic surgery and currently performing facet or selective nerve block (which can relate to a surgeon feeling comfortable with video-assisted surgery and fluoroscopic anatomy of the spine), as shown in Table 3.

    The wide variety of information regarding the learning curve needed to master these techniques can be misleading and, to one point, limit the technique’s adoption into general spine surgery practice. More than 70% of responders recognized that indications for surgery would increase with more expertise in endoscopic techniques. Surgeons recognize the advantages endoscopic surgery provides; the only thing limiting them is the intricate learning curve thought to be needed to manage these procedures.

    62% of Surgeons felt comfortable with transforaminal and interlaminar endoscopic disc decompression for the same. According to the literature available, the learning curve for the transforaminal approach was steep and easy, while the learning curve for the interlaminar approach was flat and hard to master.4 Choi et al.11 recommended supervision by an experienced surgeon in the initial ten cases to overcome the learning curve for the interlaminar procedure at L5-S1. But our results state a different reality. This can be related to the fact that most of the responders to our survey had some previous exposure or training in video-assisted surgery fluoroscopic facet block and selective nerve block or had some exposure to endoscopic surgery during their basic training as spine surgeons.

    Managing disc disease by endoscopic surgery seems to be more accepted by spine surgeons than bony decompression in all of its modalities, but no specification was made as to what restrains them from venturing into treating bony decompression (if it was the fear of using a power drill, or Kerrison Rongeurs near nervous structure from an endoscopic approach or other motive).12

    Imprecise anatomic orientation and manipulation inside the spinal canal are key factors in the steep learning curve that the full endoscopic interlaminar approach is thought to have. Obtaining microsurgical experience, attending workshops, and suitable patient selection can help shorten the learning curve and decrease complications.13

    Another result that matches the current literature is that surgeons don’t feel comfortable incorporating endoscopic spine fusion into their practice or find it proficient (only 5% of responders). As shown in Table 1, surgeons’ perception of the number of surgeries needed to master each one of the endoscopic techniques is not far from what is stated in the literature, with the perception that endoscopic spine fusion is the technique that requires more surgeries to master it.

    The main limitation we found in our study is related to the fact that it is a survey-based analytical study. Heterogeneity in clinical practices among centers may be a major confounding factor in interpreting the results.14

    Overall, we recognized that this survey is no substitute for large prospective trials, but it gives us a clear view of the perception of the learning curve needed to learn and master full endoscopic spine surgery; it gives us a view of where these techniques stand and what is limiting spine surgeons from incorporating endoscopic techniques into their practice, which seems to be mainly the lack of training in these modalities.

    Another highlight of our survey that has not been explored deeply in previous literature is the learning curve for surgeons already familiar with basic endoscopic spine surgeries, such as soft tissue transforaminal surgeries and interlaminar decompression, that wanted to incursion into endoscopic spine surgery of higher complexity such as foraminoplasties, canal stenosis decompression, thoracic transforaminal surgery, and endoscopic fusion. As stated in Table 1, our survey revealed that 22-23 endoscopic transforaminal disectomies were a reasonable number of surgeries before starting with foraminoplasties. 27-28 soft tissue interlaminar decompression was a reasonable number of surgeries before starting stenosis decompression surgery. The two procedures that our survey responders considered needed more experience were thoracic transforaminal decompression (35-36 lumbar transforaminal surgeries must be done before trying it) and endoscopic fusion for our responders 37 endoscopic spine surgeries must be done before doing this technique (Table 1). The number of procedures mentioned for each technique was the same, independent of the years of experience of the responders.

    CONCLUSION

    Several factors influence the perception of the learning curve regarding endoscopic spine surgery. We learned that spine surgeons, both the most experienced and the less experienced, perceive that the best way to learn full endoscopic spine surgery with an efficient learning curve is the summation of an observership, cadaveric or model workshop, and having an expert present while performing the first cases; we recommend spine surgeons to follow this path. The mean number of surgeries needed to feel competent in endoscopic spine surgery is 26 for disc or decompressive surgeries. It stands out that Endolif was the procedure with the least surgeons feeling competent or comfortable performing rather than cervical endoscopic spine surgery.

    Appendix 1

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    Survey Country of Origin: _______ Age: _____ Basic StudiesΥ NeurosurgeonΥ Orthopedist Current PositionΥ ResidentΥ Specialist (Without a formal training in Spine Surgery)Υ Spine Surgery FellowΥ Spine Surgeon Years of Experience: _____ Type of PracticeΥ PublicΥ Private Υ Mixed (Both Private and Public). Did you have contact with camera-assisted surgery during your training as a resident or specialist? (arthroscopic or endoscopic)Υ YesΥ No Do you perform facet or selective nerve root blocks in your practice?Υ YesΥ No Have you performed or are you performing lumbar spine endoscopic surgery?Υ Yes Υ No Have you had contact with lumbar spine endoscopic surgery? (Observership or workshop)Υ YesΥ No How many surgeries should you perform to master the transforaminal endoscopic technique?______ How many surgeries should you perform to master the interlaminar endoscopic technique?_______ What is the best way to learn a new surgical technique?Υ Cadaveric or model workshopΥ Observership with an expert surgeonΥ Observership + cadaveric workshopΥ Perform the surgery with the support of an expert.Υ All of the above. How many surgeries do you need to perform to master the technique compared to microdiscectomy? How many surgeries do you think you should do to go from soft tissue transforaminal (disc) to foraminoplasty? How many surgeries do you think you should do to go from soft tissue interlaminar (disc) to decompression due to stenosis? How many surgeries do you think you should do to go from lumbar transforaminal to thoracic transforaminal? How many surgeries should you do to start performing endoscopic fusion (ENDOLIF)? Which of the following surgical techniques do you perform that you feel comfortable with or that you consider you have mastered? Several possible options.Υ Lumbar transforaminal (disc)Υ Lumbar transforaminal (foraminoplasty)Υ Lumbar interlaminar (disc)Υ Lumbar interlaminar (lumbar stenosis)Υ Thoracic transforaminalΥ Endoscopic Fusion (ENDOLIF)Υ Posterior cervicalΥ Anterior cervical Do you have someone in your center or practice to help you with endoscopic surgery?Υ YesΥ No *Do you have someone technically proficient to help you? A Proctor, for example.Υ YesΥ No *Do you think mastering endoscopic surgery increases the indication for surgery?Υ YesΥ No *What is your main limitation to perform endoscopic surgery?Υ Lack of financial resourcesΥ Lack of training in endoscopic surgeryΥ I don’t think it is superior to other techniquesΥ The learning curve is very long for the benefits it brings. * In your experience, do you perceive a difficulty in accessing this technology?Υ yesΥ No
    • Study conducted by the Hospital Israelita Albert Einstein, Department of Orthopedics and Traumatology, Spine Group, São Paulo, SP, Brazil.

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    Publication Dates

    • Publication in this collection
      04 Oct 2024
    • Date of issue
      2024

    History

    • Received
      12 Dec 2023
    • Accepted
      19 July 2024
    Creative Common - by 4.0
    This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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