Smartphone-Based DIY Home Microsurgical Training with 3D Printed Microvascular Clamps and Japanese Noodles

Abstract

We have recently incorporated simple modifications of the konjac flour noodle model to enable DIY home microsurgical training by (i) placing a smartphone on a mug to act as a microscope with at least ×3.5–5 magnification, and (ii) rather than cannulating with a 22G needle as described by others, we have found that cannulation with a 23G needle followed by a second pass with an 18G needle will create a lumen (approximately 0.83 mm) without an overly thick and unrealistic “vessel” wall. The current setup, however, did not allow realistic evaluation of anastomotic patency as the noodles became macerated after application of standard microvascular clamps, which also did not facilitate practice of back-wall anastomoses. In order to simulate the actual operative environment as much as possible, we introduced the use of 3D-printed microvascular clamps. These were modified from its previous iteration (suitable for use in silastic and chicken thigh vessels), and video recordings were submitted for internal validation by senior surgeons. A “wet” operative field where the konjac noodle lumen can be distended or collapsed, unlike other nonliving models, was noted by senior surgeons. With the 3D clamps, the noodle could now be flipped over for back-wall anastomosis and allowed patency testing upon completion as it did not become macerated, unlike that from clinical microvascular clamps. The perceived advantages of this model are numerous. Not only does it comply with the 3Rs of simulation-based training, but it can also reduce the associated costs of training by up to a hundred-fold or more when compared to a traditional rat course and potentially be extended to low-middle income countries without routine access to microsurgical training for capacity development. That it can be utilized remotely also bodes well with the current limitations on face-to-face training due to COVID restrictions and lockdowns.

Introduction

The clinical importance of microsurgery is undoubted and continues to find novel applications from lymphedema surgery to vascularized composite allotransplantation and gender-affirmation procedures (e.g., phalloplasty). Attendance at a live, rat course remains the gold standard and is endorsed by the International Microsurgery Simulation Society [1]. Ethical concerns with regard to animal usage have led to the introduction of the 3R principles − replacement, reduction, and refinement − and an ever-increasing number of reports on nonliving alternatives. To illustrate, a recent systematic review on simulation training in microsurgery identified 64 models, ranging from live animal models to cadaveric tissues and even virtual reality simulators [2]. Curiously however, despite the plethora of models that have been reported and described, few have been validated and overall have low levels of recommendation. Spurred on by these 3R concerns as well as the ongoing COVID pandemic which has severely limited attendance at face-to-face training sessions, we sought to develop a nonliving, on-demand, and highly affordable microsurgical training model.

Methods/Design

We analyzed in detail the systematic review by Javid et al. [2] which identified 28 bench models, of which only 5 described some semblance of actual microvascular anastomosis. Interestingly, 4 of the 5 involved synthetic materials (silastic, polyvinyl, and silicone), which in our own training experiences, are not a good replica of the clinical environment as actual vessels can be distended and collapsed; such soft tissue handling skills are also just as important, if not more, than performing an anastomosis.

The remaining article by Prunières et al. [3] compared the use of a Japanese noodle against the gold standard rat femoral artery in 13 surgical residents and concluded that overall both were very similar with regard to the time and number of stitches required for performing the anastomosis, as well as the final patency and tightness of the repair. This Japanese noodle model required the use of the operating microscope in the operating room although we note that this was reported in 2014. A quick search of the literature suggested that the use of mobile computing devices was not only a possibility [4] but in fact had been reported in other specialties with just a smartphone that just about everyone has these days [5].

Indeed, we were able to utilize the Japanese noodle model (cut to approximately 3–4 cm per noodle and divided in half) to perform microsurgical anastomosis with a basic smartphone (with a magnification of ×3–5) acting as the microscope when placed on a simple stand like a mug or cup as described previously [5]. However, rather than cannulating with a 22G needle as described by Prunières et al. [3], we have found that cannulation with a 23G needle followed by a second pass with an 18G needle will create a lumen (approximately 0.83 mm) without an overly thick and unrealistic “vessel” wall. Additionally, in contrast to the original model described by Prunières et al. [3] which described keeping the noodle cannulated through the catheter, we felt that this did not fully replicate the operative environment under the microscope and was a missed opportunity to familiarize trainees with the use of microvascular clamps. Therefore, we applied stainless-steel clamps to the noodle model, and not unexpectedly, this resulted in maceration of the noodles which did not allow patency testing. As such, a further modification required incorporation of 3D-printed microvascular clamps that were previously reported (suitable for use in silastic and chicken thigh vessels) [6] to our modified Japanese noodle model and successfully addressed this limitation (shown in Fig. 1).

Fig. 1.

a Performing microvascular anastomosis using the Japanese noodle and the 3D-printed double microvascular clamps, visualizing the high-fidelity thickness of the lumen. b Anastomosis on the back wall by flipping back the double clamps. Completed anastomosis (c) and patency test after completion of the anastomosis (d); no maceration of the noodle tissue after removing the clamps.

Discussion/Conclusion

The main drawback to this smartphone-based Japanese noodle model is a very slight “lag” of roughly half-a-second or so in image transmission but can be easily overcome after a few tries when one becomes used to spatial perception through the smartphone's camera. The perceived advantages of this model are otherwise numerous. Not only does it comply with the 3Rs of simulation-based training and reduces the associated costs by up to a hundred-fold or more (2 USD for a 228 g pack of noodles [no cooking required] which will allow practice of at least 100 anastomoses [3] and production cost of 379 USD for 3D printing machine and 0.013 USD per 3D-printed double clamp [6]), but it also allows the re-creation of a “wet” operative field where the “vessel” lumen (of the cannulated noodle) can be distended or collapsed (see online suppl. Video; see www.karger.com/doi/10.1159/000521439 for all online suppl. material). To the best of our knowledge, this has not been reported in other similar, nonliving microsurgical training models previously. Furthermore, the use of a smartphone allows both “live” tutoring and “offline” video recordings for both self- and blinded-assessment of microsurgical competence based on established tools (e.g., University of Western Ontario) by trainers and can even be extended to low-middle income countries nations without routine access to microsurgical training for capacity development. As proof-of-concept of this possibility, a virtual microsurgical course based on this model was proposed to and badged by the British Association of Plastic Reconstructive and Aesthetic Surgery (BAPRAS) and the British Society for Surgery of the Hand (BSSH) and conducted for the first time on 14 October 2021 with 15 participants from across the UK (London, Glasgow, Salisbury, Portsmouth, Belfast, and Norwich), Europe (France and Sweden), and South America (Mexico); trainers were based in the UK and France. Analysis of pre- and post-course assessment scores is currently in progress to determine validity of this training modality. Finally, while this DIY home microsurgery training concept arose initially from the current COVID pandemic which has limited both face-to-face and clinical training opportunities, we believe that it can be used both before and after a standard rat course so that trainees will derive maximal benefit and maintain their newly acquired microsurgical skills, respectively.

As the late Robert Acland espoused, “preparation is the only shortcut that you need.” We believe that with this DIY set, one can now have on-demand access to high-quality microsurgery preparation and training easily.

Statement of Ethics

No ethical approval was required as this was a nonclinical study and did not involve any live animals either.

Conflict of Interest Statement

Dr. Papavasiliou owns Stelth Ltd., a company that specializes in 3D printing. The remaining authors have no financial information to declare.

Funding Sources

No funding was received for study design, collection, analysis, interpretation of data, and writing of the report. The submitted work was entirely the authors' work.

Author Contributions

Z.Y.N. participated in study planning, data collection, and analysis and interpretation of the results and wrote the manuscript. C.H. and A.G.L. participated in study planning, data collection, and analysis and interpretation of the results. A.P. participated in the supervision of the research. T.P. participated in study planning, data collection, and supervision of the research. All authors have read and approved the final manuscript.

Data Availability Statement

All data generated or analyzed during this study are included in this article. Further enquiries can be directed to the corresponding author.

Supplementary Material

Video 1

Supplemental Video

Funding Statement

No funding was received for study design, collection, analysis, interpretation of data, and writing of the report. The submitted work was entirely the authors' work.