Free tissue transfer is widely employed in reconstructive surgery to restore form and function following oncological resection and trauma. Preconditioning this tissue prior to surgery may improve outcome. This article describes an in situ transverse rectus abdominis myocutaneous flap (TRAM) in rats as a means for testing preconditioning strategies.
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Method Article
In situ Transverse Rectus Abdominis Myocutaneous Flap: A Rat Model of Myocutaneous Ischemia Reperfusion Injury
In This Article
Summary
Abstract
Free tissue transfer is the gold standard of reconstructive surgery to repair complex defects not amenable to local options or those requiring composite tissue. Ischemia reperfusion injury (IRI) is a known cause of partial free flap failure and has no effective treatment. Establishing a laboratory model of this injury can prove costly both financially as larger mammals are conventionally used and in the expertise required by the technical difficulty of these procedures typically requires employing an experienced microsurgeon. This publication and video demonstrate the effective use of a model of IRI in rats which does not require microsurgical expertise. This procedure is an in situ model of a transverse abdominis myocutaneous (TRAM) flap where atraumatic clamps are utilized to reproduce the ischemia-reperfusion injury associated with this surgery. A laser Doppler Imaging (LDI) scanner is employed to assess flap perfusion and the image processing software, Image J to assess percentage area skin survival as a primary outcome measure of injury.
Introduction
The goal of this protocol is to demonstrate a reliable and reproducible model of the ischemia-reperfusion injury observed in free tissue transfer to enable interventional strategies to be investigated.
Free tissue transfer is defined as the vascular detachment of an isolated block of tissue followed by autologous transplant of that tissue with anastomosis of the flap's transected vessels to native vessels at the recipient site. The procedure is known as FTT and the tissue being transferred referred to as the free flap.
Free tissue transfer is the gold standard approach for the correction of complex, composite de....
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Protocol
All surgery is performed in accordance with guidelines set out by the United Kingdom's Home Office and the University of Edinburgh's Veterinary Services Department.
1. Surgical Procedure Set-up Notes
- Change into clean surgical scrubs, gown, scrub cap and mask. Clean all surfaces of the operating room including equipment with 2% chlorhexidine in 70% isopropyl alcohol.
- Prior to surgery, autoclave all surgical supplies and instruments that will be used in the procedure. Sterile packs per operation should include: 3 drapes, gauze, cotton tip applicators, silicone sheeting and the surgical instruments, see the Table of ....
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Results
Rat models are more economical than larger animals models,36 are disease-resistant in nature and may be genetically manipulated. Loose skinned animals, such as rodents, were thought to have a different arrangement of cutaneous blood supply compared to fixed skinned animals such as humans and pigs. In loose skinned animals, skin is supplied primarily by direct cutaneous blood vessels passing through the subcutaneous fat to the overlying skin (Figure 4) By contrast, fixed skinned animals derive.......
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Discussion
Modifications and trouble shooting
The protocol presented here reproduces the IRI seen in free tissue transfer in an experimental system enabling further understanding of that process and provides a means to investigate means of ameliorating IRI and improving outcome. This could easily be modified to produce a more severe injury if it were based on the non-dominant, deep, inferior epigastric pedicle or if the ischemic time were increased.
Limitations of technique
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Disclosures
We have no disclosures.
Acknowledgements
This work was funded by the Medical Research Council grant G1000299.
The corresponding author would like to thank Gary Borthwick, University of Edinburgh, for assisting during the surgery.
The authors would like to acknowledge advice from Helen Douglas and Iain Mackay and allowing us to observe their Deep Inferior Epigastric (DIEP) flap procedure (Canniesburn Plastic Surgery Unit, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, UK).
The authors would also like to thank Gary Blackie at the University of Edinburgh for his help in producing the video for this article.
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| Moor LD12 laser doppler imaging scanner | http://gb.moor.co.uk/product/moorldi2-laser-doppler-imager/8 | ||
| Complete homeothermic blanket system with flexible probe. Small. 230 VAC, 50 Hz | 507221F | www.harvardapparatus.com | |
| Graeffe forceps 0.8 mm tips curved | 11052-10 | 2, http://www.finescience.de | |
| Acland clamps | 00398 V | B-1 ’V’ pattern clamps used on both artery and vein. http://www.merciansurgical.com/acland-clamps.pdf | |
| Clamp applicator | CAF-4 | http://www.merciansurgical.com/acland-clamps.pdf | |
| Gemini cautery unit | 726067 | www.harvardapparatus.com | |
| Micro-vessel dilators 11 cm 0.3 mm tips 00124 | D-5a.2 | http://www.merciansurgical.com | |
| Micro Jewellers Forceps 11cm angulated 00109 | JFA-5b | http://www.merciansurgical.com | |
| Micro Jewellers Forceps 11 cm straight 00108 | JF-5 | http://www.merciansurgical.com | |
| Acland Single Clamps B-1V (Pair) | 396 | http://www.merciansurgical.com | |
| Micro Scissors Round Handles 15 cm Straight | 67 | http://www.merciansurgical.com | |
| Iris Scissors 11.5 cm Curves EASY-CUT | EA7613-11 | http://www.merciansurgical.com | |
| Mayo Scissors 14 cm Straight Chamfered Blades EASY-CUT | EA7652-14 | http://www.merciansurgical.com | |
| Derf Needle Holders 12 cm TC | 703DE12 | http://www.merciansurgical.com | |
| Ethilon 5-0 | W1618 | http://www.farlamedical.co.uk/ | |
| Vicryl rapide 6-0 | W9913 | http://www.millermedicalsupplies.com/ | |
| Instrapac - Adson Toothed Forceps (Extra Fine) | 7973 | http://www.millermedicalsupplies.com/ | |
| Castroviejo needle holders | 12565-14 | http://s-and-t.ne | |
| Heat Lamp | http://www.chicken-house.co.uk | ||
| Silicone sheeting 0.3 mm translucent | http://www.silex.co.uk/ | ||
| Image J software | http://rsbweb.nih.gov/ij/ | ||
| Zeiss OPMI pico | http://www.zeiss.co.uk/ | ||
| Operating microscope | |||
| Vet tech solution isofluorane rig | http://www.vet-tech.co.uk/ | ||
| Vet tech solution isofluorane rig | http://www.vet-tech.co.uk/ |
References
- Wang, X., et al. Free anterolateral thigh adipofascial flap for hemifacial atrophy. Ann. Plast. Surg. 55 (6), 617-622 (2005).
- Eckardt, A., Fokas, K. Microsurgical reconstruction in the head and neck region: An 18-year ex....
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