Principles and techniques of microvascular surgery

26 Principles and techniques of microvascular surgery





Synopsis




image Microvascular surgery refers to the surgical coaptation of small vessels usually less than 3 mm in diameter.


image This technique has evolved significantly over the last four decades, starting from replantations and revascularizations to free-flap surgery.


image The operating microscope and the development of loupes, microinstruments, and microsutures have greatly aided its widespread use.


image Various techniques have been developed for the handling of small vessels. There are several ways in which the anastomosis can be performed after careful vessel preparation. The most commonly used techniques are the end-to-end, end-to-side and the use of the anastomotic coupling devices.


image Difficult situations such as vessel diameter discrepancy and poor vessel quality with atherosclerotic plaques and loose intima can usually be overcome with special techniques. Inadequate vessel length can be managed with microvascular grafts.


image While previously considered only when simpler methods of reconstruction were unfeasible, free tissue transfers have become commonplace and are now first-line options for single-stage reconstruction, with superior functional and aesthetic outcomes.


image The disadvantages of microsurgery include the steep learning curve, lengthy operative times, and the need for technical expertise and specially trained personnel.


image In free-flap surgery, indications, contraindications, and timing are critical. Good preoperative planning is required, including the selection of the appropriate flap and recipient vessels.


image Experience is vital in postoperative monitoring of free flaps; early detection of a failing free flap with prompt intervention greatly improves the salvage rates.


image The majority of complications are related to vascular compromise and many relate to pedicle thrombosis due to kinking, compression, or technical error.


image Early detection and prompt surgical exploration are mandatory if vascular compromise is suspected. Pharmacological agents such as aspirin, heparin, and dextran are also useful adjuncts.


image Despite the improvements in techniques and postoperative care, flap failure rates remain around 3%. Managing these cases can be one of the most challenging aspects of reconstructive microsurgery.


image Microsurgery has indeed revolutionized our approach to reconstructive challenges. With further refinements, we will see an even wider application, particularly in the fields of supramicrosurgery, freestyle free flaps, composite tissue allotransplantation, and tissue engineering.



Introduction


Microsurgery refers to surgery that takes place under microscope magnification. Within the field of plastic surgery, it encompasses microvascular, microneural, microlymphatic, and microtubular surgery. Specifically, microvascular surgery refers to the surgical coaptation of small vessels performed under magnification and illumination. In a clinical setting, it is often used synonymously with the term “reconstructive microsurgery,” and is implied in replantations and free tissue transplantations.


The introduction of the operating microscope in 1960 heralded the beginnings of the era of microsurgical reconstruction and it is generally used with vessels which are 3 mm or less in diameter in conjunction with specially designed fine instrumentation and microsutures. As an alternative, surgical loupes with magnifications of 2.5×–8× can be used.


Over the last four decades, microvascular surgery has become an indispensable tool for the reconstruction of complex defects. While previously considered only when simpler methods of reconstruction were unfeasible, free tissue transfers have become commonplace and are now being considered as a first-line option to provide superior outcomes, both functionally and aesthetically. Other benefits include time effectiveness and better economy in breast, head and neck, and extremities reconstruction, with even psychological advantages.


There are, of course, also disadvantages of microsurgery, including the steep learning curve, lengthy operative times, need for special resources, technical expertise, and considerable investment in instruments and specially trained personnel. Despite improvements in techniques and postoperative care, there is a small but not insignificant risk of flap failures of 2–3% even in the best surgical units.


This chapter details the tools and techniques used to maximize microvascular surgical outcome. Also discussed are the principles of microvascular surgery particularly with respect to free-flap surgery, options available when failure occurs, and the future of microvascular surgery. Replantations are highlighted in a separate chapter.

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