- Department of Surgical Neurology, Research Institute for Brain and Blood Vessels-Akita, 6-10 Senshu-Kubota-machi, Akita 010-0874, Japan
- Ono and Co., Ltd., 2-12-5 Ginza, Chuo-ku, Tokyo 104-0061, Japan
Department of Surgical Neurology, Research Institute for Brain and Blood Vessels-Akita, 6-10 Senshu-Kubota-machi, Akita 010-0874, Japan
DOI:10.4103/2152-7806.72626© 2010 Mutoh T 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 author and source are credited.
How to cite this article: Mutoh T, Ishikawa T, Ono H, Yasui N. A new polyvinyl alcohol hydrogel vascular model (KEZLEX) for microvascular anastomosis training. Surg Neurol Int 23-Nov-2010;1:74
How to cite this URL: Mutoh T, Ishikawa T, Ono H, Yasui N. A new polyvinyl alcohol hydrogel vascular model (KEZLEX) for microvascular anastomosis training. Surg Neurol Int 23-Nov-2010;1:74. Available from: http://sni.wpengine.com/surgicalint_articles/a-new-polyvinyl-alcohol-hydrogel-vascular-model-kezlex-for-microvascular-anastomosis-training/
Background:Microvascular anastomosis is a challenging neurosurgical technique that requires extensive training for one to master it. We developed a new vascular model (KEZLEX, Ono and Co., Ltd., Tokyo, Japan) as a non-animal, realistic tool for practicing microvascular anastomosis under realistic circumstances.
Methods:The model was manufactured from polyvinyl alcohol hydrogel to provide 1.0–3.0 mm diameter (available for 0.5-mm pitch), 6–8 cm long tubes that have qualitatively similar surface characteristics, visibility, and stiffness to human donor and recipient arteries for various bypass surgeries based on three-dimensional computed tomography/magnetic resonance imaging scanning data reconstruction using visible human data set and vessel casts.
Results:Trainees can acquire basic microsuturing techniques for end-to-end, end-to-side, and side-to-side anastomoses with handling similar to that for real arteries. To practice standard deep bypass techniques under realistic circumstances, the substitute vessel can be fixed to specific locations of a commercially available brain model with pins.
Conclusion:Our vascular prosthesis model is simple and easy to set up for repeated practice, and will contribute to facilitate “off-the-job” training by trainees.
Keywords: Microvascular anastomosis, neurosurgical training, polyvinyl alcohol hydrogel, vascular model
Microvascular anastomosis remains a challenging neurosurgical technique which requires extensive training for one to master it. Since clinical opportunities to experience such procedures on actual patients are limited, neurosurgeons are expected to develop and maintain their microsurgical skills with regular “off-the-job” practice alone. Typical laboratory microvascular training has been performed using artificial materials (such as gauze and silicone tube)[
Polyvinyl alcohol (PVA) hydrogel has realized a biomodeling with mechanical properties similar to real cerebral vasculatures.[
Description of the model
The vascular substitute [
For selecting an appropriate size for anastomosis training, a thinner tube of 1.0 mm in diameter may be used as a substitute for recipient cortical arteries (M4), intermediate size tubes of 1.5 mm in diameter for recipient cerebral arteries such as the insular segment (M2–M3) of the middle cerebral artery (MCA) and callosal segment (A2–A3) of the anterior cerebral artery (ACA), and thicker tubes of 2.0–3.0 mm in diameter to simulate donor arteries such as the superficial temporal artery (STA) and radial artery (RA).
Trainees can acquire basic microsuturing techniques (i.e., gentle and precise preparation of the donor and recipient vessels and correct suture placement without penetrating the walls of other vessels) for end-to-end, end-to-side, and side-to-side anastomoses, with handling and visibility similar to that of real arteries. The segment for arteriotomy can be colored with methylrosaniline (pyoctaninum blue) dye for clear visualization [
Deep anastomosis has different levels of difficulty depending on depth. To practice standard deep bypass techniques to M2, the superior cerebellar artery, posterior cerebral artery, posterior inferior cerebellar artery, or callosal segment of the ACA as a recipient in realistic conditions, the substitute vessel can be fixed to specific locations of a commercially available brain model (KEZLEX #A36, Ono and Co., Ltd.)[
A set-up for practicing standard deep bypass (STA to M2). (a) To simulate a deep operative field, vascular models were placed onto the insular cortex of the artificial brain model with pins, a silicone sheet was inserted under the vessel, and the artificial brain was retracted with a brain spatula. (b) For preparation of end-to-side anastomosis, the prostheses were colored with pyoctaninum blue dye for clear visualization of the vessel walls as in actual surgery. Note that the views of the brain and vascular model (a, b) closely resemble real operative fields for microsurgical anastomosis (c, d)
Training in surgical skills is of great importance in mastering the techniques of microvascular anastomosis, which are indispensable in daily routine practice. Two major issues have been discussed in microsurgical training. The first involves the development of appropriate vascular substitutes. Gauze fibers,[
The cost of the vascular prosthesis is another important factor for ideal training models. Unfortunately, current model is 1.5 times more expensive than commercially available microvascular practice model with silicone tubes fixed in a pocket-sized card (Microvascular Practice Card, Muranaka Medical Instruments Co. Ltd., Osaka, Japan).[
The second issue is how situations of technical difficulty similar to actual vascular anastomosis can be reproduced. Deep microvascular anastomosis is a far more difficult technique than shallow STA–cortical MCA anastomosis, and few practical tools have been available for training in it. With installation of our vascular prostheses in brain models, we have demonstrated[
Taken together, these considerations indicate that our new vascular substitute model will facilitate the development and maintenance of microsurgical skills in both resident neurosurgeons and experts who wish to master the various levels of microanastomosis techniques.
1. Aboud E, Al-Mefty O, Yasargil MG. New laboratory model for neurosurgical training that simulates live surgery. J Neurosurg. 2002. 97: 1367-72
2. Bishop AJ, Glasby MA, Houlton JE. A morphological assessment of vein allografts preserved in glycerol and used for arterial replacement. J Cardiovasc Surg (Torino). 1987. 28: 491-7
3. Colpan ME, Slavin KV, Amin-Hanjani S, Calderon-Arnuphi M, Charbel FT. Microvascular anastomosis training model based on a Turkey neck with perfused arteries. Neurosurgery. 2008. 62: ONS407-10
4. .editors. Deep anastomosis using KEZLEX #A36 and #B61. Tokyo: Ono and Co Ltd. p.
5. Fahner PJ, Idu MM, van Gulik TM, Legemate DA. Systematic review of preservation methods and clinical outcome of infrainguinal vascular allografts. J Vasc Surg. 2006. 44: 518-24
6. Hino A. Training in microvascular surgery using a chicken wing artery. Neurosurgery. 2003. 52: 1495-1497
7. Hwang G, Oh CW, Park SQ, Sheen SH, Bang JS, Kang HS. Comparison of different microanastomosis training models: Model accuracy and practicality. J Korean Neurosurg Soc. 2010. 47: 287-90
8. Inoue T, Tsutsumi K, Adachi S, Tanaka S, Saito K, Kunii N. Effectiveness of suturing training with 10-0 nylon under fixed and maximum magnification (× 20) using desk type microscope. Surg Neurol. 2006. 66: 183-7
9. Ishikawa T, Yasui N, Ono H. Novel brain model for training of deep microvascular anastomosis. Neurol Med Chir (Tokyo). 2010. 50: 627-9
10. Kanazawa R, Teramoto A. The realization of preferable operative working space through the microsurgical training with rats-the importance of the process. Surg Neurol. 2009. 71: 380-7
11. .editors. KEZLEX. Tokyo: Ono and Co Ltd. p.
12. Kosukegawa H, Mamada K, Kuroki K, Liu L, Inoue K, Hayase T. Evaluation of compliance of poly (vinyl alcohol) hydrogel for development of arterial biomodeling. IFMBE Proc. 2009. 23: 1993-5
13. Krishnan KG, Dramm P, Schackert G. Simple and viable in vitro perfusion model for training microvascular anastomoses. Microsurgery. 2004. 24: 335-8
14. Matsumura N, Hayashi N, Hamada H, Shibata T, Horie Y, Endo S. A newly designed training tool for microvascular anastomosis techniques: Microvascular Practice Card. Surg Neurol. 2009. 71: 616-20
15. Meier SA, Lang A, Beer GM. Polyurethane vessels for microvascular surgical training to reduce animal use. ALTEX. 2004. 21: 135-8
16. Meyer EP, Beer GM, Lang A, Manestar M, Krucker T, Meier S. Polyurethane elastomer: A new material for the visualization of cadaveric blood vessels. Clin Anat. 2007. 20: 448-54
17. Ohta M, Handa A, Iwata H, Rufenacht DA, Tsutsumi S. Poly-vinyl alcohol hydrogel vascular models for in vitro aneurysm simulations: The key to low friction surfaces. Technol Health Care. 2004. 12: 225-33
18. Olabe J. Microsurgical training on an in vitro chicken wing infusion model. Surg Neurol. 2009. 72: 695-9
19. Olabe J, Sancho V. Human cadaver brain infusion model for neurosurgical training. Surg Neurol. 2009. 72: 700-2
20. Remie R. The PVC-rat and other alternatives in microsurgical training. Lab Anim (NY). 2001. 30: 48-52
21. Tellioglu AT, Eker E, Cimen K, Comert A, Karaeminogullari G, Tekdemir I. Training model for microvascular anastomosis. J Craniofac Surg. 2009. 20: 238-9