Chapter 10 colour duplex sonography (CDS), digital subtraction angiography (DSA), computed tomography angiography (CTA), and magnetic resonance angio- graphy (MRA) can all be useful. Among the tools that can be used to identify the best perforator the gold standard is the CTA: the problem is that CTA gives radiation (5,6 mSv). For this reason in our institution the gold standard is the MRA, not harmful for the patient, with good results as shown in chapter 5,6,7 and 8. Sometimes a combination of instruments may be used to identify not only the presence of a perforator vessel but also the best one. In many cases, if the best perforator can be selected, a single perforator vascularises the entire flap. In our later studies we analysed the variability of the perforators with imaging in DIEP flaps, sc-GAP and sc-TFL flaps and we identified the best perforator were more perforators for a flap were present. The best perforator is chosen based upon maximising the ease and speed of operation and the clinical experience of complication. In the Navarra experience4 for example, the authors described the characteris- tics of the best perforator for the DIEP flap on preoperative imaging. Most of the principles defining the best perforator for a DIEP flap could be translated to perforator flaps in general. In DIEP-flap surgery the authors analysed the most favourable anatomy for a perforator of a DIEP flap dividing the vascularisation of the flap in different segments: the deep inferior epigastric artery (DIEA) course deep to the rectus abdominis muscle, the intramuscular course of the DIEP, the intramuscular course of the DIEP perforator, the course of the perforator at the fascia level and the subcuta- neous course of the perforator. The ‘ideal’ vascular pedicle could thus be described in terms of these segments: 1. Large calibre of all segments: the greater the size of the DIEA pedicle and perforator the better was the inflow in the flap. 2. Central location within the flap: centrality of the perforator similarly maximised the supply to the peripheral parts of the flap because of more connections with the network in all directions. 3. Short longitudinal intramuscular course: this could be associated with ease and speed of dissection and the likelihood of less muscular branches requiring ligation. Some groups routinely used one single perforator as the sole supply to the DIEP flap while other groups described the routine application of two or more perforators. If more than one perforator was used the distance between the vessels and their intramuscular course were essential to reduce the need for muscle sacrifice and dissection. 167
5. lay-out phd DEFINITIEF_digitaal2
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