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Radiographic imaging is an important adjunct
in microsurgical reconstruction. The goals of preoperative imaging include
the identification of vascular anomalies or abnormalities which could
alter the surgical plan. Preoperative imaging is particularly helpful
following trauma to help define the zone of injury, the quality of
potential recipient arteries as well as the location and patency of
potential recipient veins. In addition, post-operative imaging may be
useful to evaluate the patency of a vascular anastomosis, the position or
viability of a bone flap.
Angiography has long been the gold standard
modality for vascular imaging in microsurgical reconstruction.1-4
There are several drawbacks to traditional angiography.5-7
Therefore, the use of less invasive imaging modalities including magnetic
resonance angiography (MRA), computer tomographic angiography (CT angio)
and duplex ultrasound has become increasingly popular. Each modality has
particular advantages as well as disadvantages and each has different
potential utility in microsurgical reconstruction.
To Image or Not to Image
The importance of preoperative imaging in
microsurgical reconstruction has been well established. While the
indications for preoperative angiography are surgeon and institution
dependent, there are a number of anatomic abnormalities which could
significantly affect the surgical plan and outcome of microsurgical
reconstruction. Angiography of the lower extremity following trauma and
prior to reconstruction, particularly if there is an abnormal peripheral
pulse examination is clearly warranted. In addition, the use of ultrasound
can also be helpful to determine the patency of the superficial and deep
venous systems particularly in cases where there is a significant zone of
injury.
There has been considerable controversy as to
the indications for preoperative imaging to evaluate the fibular donor
sites. 1-4,8,22-24 The reluctance to perform routine
angiography is attributable, in large part, to the potential complications
of traditional angiography. Congenital abnormalities such as peronea magna
sydnrome, in which the peroneal artery represents the major arterial
supply to the foot and the peripheral pulse exam may be normal, would
certainly be a contraindication to fibula transfer. 8 In
addition, acquired abnormalities secondary to peripheral vascular disease
or lower extremity trauma could be potential contraindications to the use
of the fibula.
There have been several studies which suggest
that routine angiography is not indicated prior to fibula harvest. Jones
et al. reported 650 successful free fibular transfers without preoperative
imaging., including his own experience as well as the experience of four
other surgeons. 8 Others have reported that angiography can be
useful in the cases where lower extremity pulse examination is abnormal.
Disa and Cordeiro reported no complications with selective use of
angiography only in patients with abnormal physical examination. 2
However, Young et al. found abnormalities in 25 percent of patients
studied prior to planned use of the free fibula flaps, and half of these
patients had normal preoperative vascular exams. 3
It is clear that imaging can be of critical
importance in operative planning and to identify abnormalities which can
influence the selection of suitable recipient vessels and also of suitable
donor sites, particularly in the case of the fibula. The development of
safer imaging modalities which are capable of providing accurate images
should certainly shift the risk benefit ratio further in the favor of
routine vascular imaging.
References
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