The learning curve of bilateral laparoscopic varicocelectomy: a prospective study

ABSTRACT Varicocele occurs in 15% of general male population and in 35% of infertile men. Since 1992, surgical correction with laparoscopic varicocelectomy is the gold standard for treatment of symptomatic patients or patients with abnormal seminal analysis. The learning curve for this frequently performed procedure has not yet been described. In the present study, we investigated the learning curve of a single urologist in training performing his first 21 laparoscopic varicocelectomies using qualitative and quantitative tools to evaluate his performance during the process. Our results show that 14 bilateral laparoscopic varicocelectomies are enough to achieve the plateau of the learning curve.


INTRODUCTION
V aricocele is an abnormal dilatation of the pampiniform plexus, the plexus responsible for venous drainage and thermal regulation of the testes 1 .This condition is present in 15% of healthy men and in up to 35% of men with primary infertility.Despite being usually asymptomatic, varicocele can also present with scrotal discomfort, local edema, and other symptoms 2,3 .
Varicocele treatment is indicated in case of palpable varicocele, abnormality in seminal analysis, abnormal sperm function tests, or a 20% differential in testicular volume that is persistent for more than one year in adolescents.Varicocele correction can also be considered in patients with testicular pain or abnormal testosterone production 4,5 .
The first technique for varicocele treatment was open varicocelectomy.Currently, it has been used less frequently due to a higher rate of complications, with an incidence of 5 to 30%, including hydrocele, testicular atrophy, inadvertent ligation of the vas deferens, epididymitis, hematoma, and surgical site infections 6 .
Laparoscopic varicocelectomy was first introduced to treat male infertility in 1992 and almost all of its risks and benefits have been extensively studied 7,8 .
More recently, new varicocelectomy techniques have been developed, such as subinguinal, microsurgical varicocelectomy, preferred in several guidelines for presenting slightly better results in relation to the reduction of complications and recovery of fertility 9 , robotic-assisted varicocelectomy 10 , laparoscopic varicocelectomy with lymphatic preservation 11 , and single-port varicocelectomy 12 .Even so, traditional laparoscopic varicocelectomy remains a viable alternative for varicocele correction 9,13,14 .
The learning curve in surgery has become an increasingly frequent theme in the literature with the advent of robotic surgery, since unfamiliarity with the former would be an obstacle to the popularization of the latter.Thus, multiple studies have been published on robotic prostatectomy, nephrectomy, and pyeloplasty [15][16][17][18][19] .Following this trend, the learning curve of less complex procedures also began to be investigated, although to a lesser extent.The COVID-19 pandemic significantly increased the relevance of this topic, as the restrictions imposed by the pandemic drastically reduced the number of elective procedures available for training during residency programs 20 .
Consequently, the learning curve of the most diverse urological procedures began to be studied, such as correction of hypospadias 21 , implantation of penile prostheses 22 , urethroplasty 23 , percutaneous nephrolithotomy 24 , prostatic biopsy 25 , and others.
Interestingly, we noticed a scarcity of studies on the learning curve of laparoscopic varicocelectomy.
The only study on the subject was published by Wang et al. 26 and explored the differences in the varicocelectomy learning curve by comparing group A (who performed laparoscopic varicocelectomy with a laparoscopic training box) with group B (who trained with a virtual reality simulator).No statistical difference was observed between groups and the learning curve plateau was reached after 29 cases.
The primary objective of the present study is to describe, in an unprecedented way, the learning curve of bilateral laparoscopic varicocelectomy in supervised training, in adult patients [27][28][29] .

METHODS
In this study, we analyzed the first 21 immediately consecutive bilateral laparoscopic varicocelectomies performed by the same surgeon.All patients had venous reflux present on preoperative Doppler and no longer had reflux on postoperative ultrasound performed after 6 months.The surgeries were divided into three groups according to the order performed: from the first to the seventh -Group I; from the eighth to the 14 th -Group II; and from the 15 th to the 21 st -Group III.

Surgical procedure
The patient, under general anesthesia, was

Data collection
We collected data regarding patients' age, total operative time (in minutes), complications, and postoperative pain on the 1 st postoperative day, 7 th postoperative day, 1 month, and 6 months after the

Belkovsky
The learning curve of bilateral laparoscopic varicocelectomy: a prospective study Depth perception a,b 1 -Constantly overshoots target, wide swings, slow to correct 2.
3 -Some overshooting or missing target, but quick to correct 4.

-Accurately directs instruments in the correct plane to target
Bimanual dexterity a,b 1 -Uses only one hand, ignores non dominant hand, poor coordination between hands 2.
3 -Users both hands, but does not optimize interaction between hands 4.
5 -Expertly uses both hands in a complementary manner to provide optimal exposure Efficiency a,b 1 -Uncertain, inefficient efforts; many tentative movements; constantly changing focus or persisting without progress 2.
procedure, through a numerical scale from 1 to 10, 1 being described as no pain and 10 being the worst possible pain.
In addition, we performed a qualitative analysis, based on a previously validated instrument 29 .

Qualitative Score
To assess surgical skill, we used the GOALS (Global Assessment of Laparoscopic Skills) score, described by Vassiliou et al. in 2003 29 .GOALS was initially developed for the qualitative evaluation of laparoscopic surgeries by a human observer and has since been applied in several areas, from measuring the impact of using simulators for surgical learning to the development of machine learning models 30,31 .It considers 5 skill domains in laparoscopic surgery and assigns a score from 1 to 5 to each of them, according to Table 1.
5 -Confident, efficient and safe conduct, maintains focus on task until it is better performed by way of an alternative approach Tissue handling a,b 1 -Rough movements, tears tissue, injures adjacent structures, poor grasper control, grasper frequently slips 2.
3 -Handles tissue reasonably well, minor trauma to adjacent tissue (i.e., occasional unnecessary bleeding or slipping of the grasper) 4.
5 -Handles tissues well, applies appropriate traction, negligible injury to adjacent structures Autonomy a,b 1.Unable to complete entire task, even with verbal guidance 2.
3. Able to complete task safely with moderate guidance 4.
5. Able to complete tasks independently without guidance.

Statistical analysis
We evaluated the groups using the Kolmogorov-Smirnov test to confirm normal distribution.All variables showed normal distribution and were subsequently compared by ANOVA.Afterwards, we used the Tukey's post-test for intergroup comparisons.

Ethics and Financing
The study was approved by the Ethics Committee of the University Hospital of the Faculty of Medicine of USP and was conducted without funding sources.

RESULTS
The age of the patients was similar between the studied groups: in group I, 30.01 years, with a Standard Deviation (SD) of ± 6.7; in group II, 33.5 years ± 3; in group III, 35.5 years ± 6.2.

The learning curve of bilateral laparoscopic varicocelectomy: a prospective study
The qualitative analysis of the GOALS variables showed improvement when comparing groups I and II in bimanual dexterity (p=0.007),depth perception (p=0.015), and autonomy (p=0.015).However, there was no difference when comparing groups II and III in any of the qualitative variables, as can be seen in Table 2.We did not observe pain 1 month after the procedure, nor any postoperative complications (such as recurrence of varicocele, hydrocele, or testicular atrophy).
In the control USG 6 months later, there was no clinically significant varicocele.

DISCUSSION
The literature shows that laparoscopic repair presents better results than the open approach (shorter surgical time, less postoperative pain, shorter hospital stay, and earlier return to daily activities) 32 .
Scientific interest in understanding learning curves has grown dramatically over the past 20 years.
Incidentally, the number of publications on the subject indexed in PubMed increased from 146 in 1996 to 1,070 in 2016.Research in the area takes place in different surgical procedures, such as hepatectomy, colorectal surgeries, and radical prostatectomy, with surgeons with different experiences, from beginners to seasoned ones 33,34 .
The description of the learning curve of bilateral laparoscopic varicocelectomy can be used as an essential tool for the development of more effective programs for surgical training, reducing the risk of complications and improving patients' quality of life 35 .
In this study, we observed that laparoscopic varicocelectomy progresses with satisfactory clinical results from the first surgery.This is evidenced by nonrecurrence of varicocele and absence of complications 1 and 6 months after the procedure.
Moreover, with professional training, there is also a statistically significant improvement in surgical time, surgical skill measured by the qualitative score, In the quantitative analysis, the total operative time (38.5±4.7 min vs 31.7±7.2min, p=0.058) and pain on the 7 th postoperative day (3.5±1.5min vs. 1.8±1.4min,p=0.052) were significantly lower when comparing groups I and II.However, there was no difference between groups II and III regarding the observed quantitative variables (operative time, postoperative pain, and number of complications), as shown in Table 3.

Belkovsky
The learning curve of bilateral laparoscopic varicocelectomy: a prospective study and postoperative pain in the first week.The absence of statistical difference in these variables between groups II and III allows us to infer that the plateau of the laparoscopic varicocelectomy learning curve occurs after 14 surgeries.
The reduction in surgical time observed in the present study, concomitant with the increase in surgical skill as the surgeon accumulates experience, are in line with previous results demonstrated in the literature 36,37 .
Reduction in operative time reduces anesthetic time and the probability of postoperative complications 32 .
Wang et al. 26 observed the learning curve plateau with 29 procedures, but did not observe whether there is a correlation between the learning curve in the simulator and in practice.Our study, however, featured a faster plateau curve directly in the patient, which raises the question of the place of simulators in learning laparoscopic varicocelectomy.Perhaps because it is a technically simple procedure, a surgeon familiar with laparoscopy can easily master the technique.
The external validity of the results is limited because we used a retrospective analysis of a database prospectively fed with data from a single surgeon.
Even so, considering the difficulty of accessing data on the surgical learning curve and ethical issues related to patient safety and confidentiality, it is still customary for such studies to describe the learning curve of a single surgeon, especially for urologists [16][17][18] .In addition, we did not assess anatomical variations or differences in BMI between patients, factors that could interfere with learning difficulties, and the comparative seminal analysis was not available for statistical analysis.
On the other hand, surgical learning in patients with varicocele is a point that increases the reliability of the learning curve when compared to artificial or in vitro models.Furthermore, this study dispensed with special, high-cost disposable materials (such as robotic and microscopic materials, ultrasonic scalpels, and disposable clips), using only permanent instruments, which makes it more faithful to the Brazilian reality 4,7,38 .

CONCLUSION
We did not observe statistical difference in the studied parameters (surgical skill and total operative time) between groups II and III.Thus, we can estimate that 14 bilateral laparoscopic varicocelectomies are enough for a surgeon to reach proficiency in the learning curve.

R E S U M O R E S U M O
placed in horizontal dorsal decubitus, slightly inclined in the Tredenlenburg position.A periumbilical incision was made with a Veress needle and pneumoperitoneum was inflated with a pressure of 10mmHg.A 10mm trocar was positioned in the umbilicus, and two other 5mm trocars were positioned approximately 8cm laterally to the camera trocar (Figure1).