Kidney tumor represents 3% of all tumors. Despite this, its incidence has been increasing over the last two decades. In Europe, mortality has begun to stabilize and even decrease since 1990 (1). While in its initial stages it can be cured by local treatment, it is lethal when it becomes metastatic.
Fortunately, Robson's classic diagnostic triad (gross hematuria, flank pain and palpable mass) is less and less frequently observed and has been replaced by the incidental diagnosis of small and medium-sized renal occupying masses that are usually not associated with distant disease.
At the same time, in the last decade the oncological equivalence of partial surgery with radical surgery has been established, also demonstrating the functional benefit of renal preservation and the need to perform it whenever it is technically feasible in patients with T1 tumors (Guidelines of the European Association of Urology 2021).
The recognized morbidity of lumbar and abdominal access for the treatment of these tumors prompted the development of laparoscopic techniques and later gave way to robotic techniques.
In summary, the increased incidental detection of renal tumors, the oncologic equivalence of nephron-sparing surgery and the superlative results of the minimally invasive approach have made laparoscopic partial nephrectomy (LPN) the ideal technique for the treatment of renal tumors. Therefore, it is logical that at present it is essential to learn and disseminate LPN.
How is laparoscopic partial nephrectomy taught today?
The classic Halstedian axiom of witnessing a procedure, then collaborating in a similar procedure and finally trying to reproduce it, has become obsolete in the face of the sophistication of modern surgery.
Currently, very few procedures can be taught by simple emulation and especially minimally invasive techniques require strict supervision and a lot of practice before they can be safely reproduced. To this end, curricula and courses have been developed to pave the way and minimize the consequences of learning for the patient.
Complications and learning curves are not negligible in LPN. Wheat et al. evaluated complications in 336 consecutive laparoscopic partial nephrectomies. They reported a total of 35.7% complications with 6.6% classified as major. They concluded that tumor diameter, depth of penetration and advanced age were associated with increased risk of complications (2).
Place for simulation
Simulation is defined as "the technique of replacing or amplifying real experiences with guided experiences that evoke or replicate fundamental aspects of the real world in an interactive manner". In a recent systematic review of simulation in laparoscopic surgery, the authors concluded that simulation-based training has great benefits when compared to standard training (3).
Several LPN training platforms have been developed for this technique. Some of them are virtual, such as the "Procedicus MIST nephrectomy training platform" developed by Brewin et al. in 2011 (4). However, these virtual simulators are very expensive and fail to duplicate the actual feel of the procedure. Hung et al. reported a novel ex-vivo model for robotic partial nephrectomy. Using an expanded polyurethane sphere glued to a porcine kidney, the authors created a model that is easy to reproduce, but with significant limitations (5). Recently Melnyk et al. reported the results of an extensive study of materials and formulations aimed at replicating the properties of kidney tissue. The authors were able to mimic almost perfectly the mechanical response of the porcine kidney (6). Although this experience is very promising, these materials are still too expensive for the mass production necessary to be used in training.
In addition to the aforementioned difficulties in being able to develop the skills necessary for safe LPN, in 2020 a variable, hitherto unknown to modern medicine, was added. From the onset of the pandemic and in successive waves of SARS COVID-19, surgical volume decreased considerably. Consequently, residents and fellows were affected in their learning and training.
An interesting paper by Schlottmann et al. describes the major impact of the pandemic on the training of residents and fellows (Fig. 1) (7).
This unusual situation has led to compensate for this deficit with new training tools. On the one hand, these new tools should make it possible to generate the basic skills required to deal with LPN and, on the other hand, they should do so safely with the limitation of a low surgical volume.
A new tool is born
With all of the above in mind, a collaborative working group called UROTRAINER emerged in late 2019. To facilitate LPN training, the VK-1, an operable silicone and rubber-based model, was developed. The VK-1 has an 80% similarity with the renal parenchyma, making the difference imperceptible when operated laparoscopically.
This model comprises multiple tumors with simulation of individual vasculature forming different surgical scenarios of varying complexity. In this way, it allows training not only novice surgeons but also more experienced ones (Fig. 2).
The VK-1 Urotrainer has been validated for construction, appearance, content and reliability in a multicenter work performed between the German and Italian Hospitals of the City of Buenos Aires (The results will be presented in Abstract 21-5693 during the American Urology Congress 2021).
The combination of the simplicity of the model together with the massive adoption of video-call platforms has allowed the creation of a new training modality, the "Virtual Hands-on". In this way, surgeons in training can train from the comfort of their center or even from home.
We believe that simulation with this type of new tools will become a vital part of the training of any surgeon interested in performing minimally invasive partial nephrectomies, allowing to be tutored both in person and remotely.
Source: https://caunet.org/news/evolucau2021/ - American Urological Association
B. Ljungberg (Chair), L. Albiges, J. Bedke, A. Bex (Vice-chair), U. Capitanio, R.H. Giles (Patient Advocate), M. Hora, T. Klatte, T. Lam, L. Marconi, T. Powles, A. Volpe
Guidelines Associates: Y. Abu-Ghanem, S. Dabestani, S. Fernández-Pello Montes, F. Hofmann, T. Kuusk, R. Tahbaz. EAU Guidelines on Renal Cell Carcinoma 2021
Wheat JC, Roberts W, Hollenbeck B, Wolf S, Weizer AZ. Complications of laparoscopic partial nephrectomy. Urologic Oncology: Seminars and Original Investigations. Vol31, 2013;57-62.
Zendejas B, Brydges R, Hamstra SJ, Cook DA. State of the evidence on simulation-based training for laparoscopic surgery: a systematic review. Ann Surg 2013;257(4):586–593
Brewin J, Nedas T, Challacombe B, Elhage O, Keisu J, Dasgupta P. Face, content and construct validation of the first virtual reality laparoscopic nephrectomy simulator. BJU Int. 2010;106(6):850-854. doi:10.1111/j.1464410X.2009.09193.x
Hung AJ, Ng CK, Patil MB, et al. Validation of a novel robotic-assisted partial nephrectomy surgical training model. BJU Int. 2012;110(6):870-874. doi:10.1111/j.1464-410X.2012.10953.x
Melnyk R, Ezzat B, Belfast E, et al. Mechanical and functional validation of a perfused, robot-assisted partial nephrectomy simulation platform using a combination of 3D printing and hydrogel casting World J Urol. 2020;38(7):1631-1641. doi:10.1007/s00345-019-02989-z
Angeramo CA, Schlottmann F. Impact of COVID-19 on surgical residency programs: A glass half-full reflection. Int J Surg. 2021 Apr 27;89:105958. doi: 10.1016/j.ijsu.2021.105958. Epub ahead of print. PMID: 33930571; PMCID: PMC8078056.