Keywords
Free tissue flaps - Perforator flaps - Mastectomy - Breast neoplasms - Tomography,
X-ray computed
INTRODUCTION
The deep inferior epigastric artery perforator (DIEP) flap is the gold standard for
breast reconstruction [1]. The selection of a suitable muscle perforator from the deep inferior epigastric
artery is essential to flap viability. Historically, perforators were located preoperatively
by Doppler, and directly at the time of dissection based on their calibre [1]. Advances in imaging, particularly computed tomography angiography (CTA), has facilitated
preoperative perforator identification, allowing for improved flap design and shorter
operating times [2]. At present, this is achieved by measuring the reported distances, using 2 vectors,
inferior and lateral to the umbilicus, and marking these on the patient's abdomen.
Our unit has routinely used preoperative CTA for over 10 years. During this time,
we have noted that this process may be unnecessarily time-consuming and that 'mapping
errors' may occur to further decrease the efficiency of the preoperative perforator
marking process. Observation errors have been encountered where inaccurate perforator
vector measurements have been reported in relation to the umbilicus. Transcription
errors have been noted where confusing and wordy reports have been typed or where
incorrect units have been given (millimetres vs. centimetres). Interpretation errors
have also occurred when using the report for preoperative marking. The use of templates
has been shown to be a simple, efficient and cost-effective way of increasing preoperative
marking accuracy, reducing theatre time and improving outcomes, having previously
been used for reconstruction of the infra-mammary fold and breast mound planning with
DIEP flap reconstructions [3],[4].
We describe the use of a novel bespoke template, generated on a grid and taken in
a standardised manner directly from CTA images, which increases the speed and accuracy
of preoperative patient marking by overcoming DIEP perforator 'mapping errors.'
IDEA
Preoperative CTA is undertaken, with the umbilicus identifiable due to the use of
contrast. After exclusion of the smallest perforators, the remaining suitable perforators
are mounted onto a coronal-axis grid at umbilical level and reported by the radiology
department ([Fig. 1]). After careful surgical review and perforator selection at a subcutaneous plane
just anterior to the rectus sheath, the image is inserted, to scale, into a word processor
template page with standardised margins and a built-in ruler to ensure a 1:1 printing
size without requiring size adjustment. The image is printed onto a transparent acetate
sheet and holes 'punched' through the carefully selected perforators using a 3.0-mm
biopsy punch (Stiefel Laboratories Inc., North Carolina, USA) ([Fig. 2]). The acetate is laid onto the abdomen, also marked preoperatively from the sternal
notch to pubic symphysis, carefully centred at the umbilicus and lined up with the
patient's midline. The perforator sites are marked directly onto the abdomen through
the punched acetate holes ([Figs. 3]
[]). In all cases, perforator locations were confirmed with Doppler USS and found intraoperatively
under the abdominal skin markings.
Fig. 1 Coronal computed tomography angiography, generated by radiology, with marked
midline and umbilical axes (green lines) and perforators (blue arrows) (scale=5 cm,
1 cm2 grid)
There were 2 perforators on the left and 2 on the right hemi-abdomen, all perforating
the rectus sheath: a 1.0-mm calibre subcutaneous segment perforator 31 mm lateral
and 18 mm inferior to the umbilicus on the right side (blue arrow), a 0.7-mm subcutaneous
segment perforator 53 mm lateral and 19 mm inferior to the centre of the umbilicus
on the right side (not marked), a 1.0-mm subcutaneous segment perforator 38 mm lateral
and 45 mm inferior to the centre of the umbilicus on the left (blue arrow) and a 1.1-mm
subcutaneous segment perforator 53 mm lateral and 26 mm inferior to the centre of
the umbilicus (blue arrow).
Fig. 2 Acetate print reproduction of generated computed tomography angiography image
(to scale)
The 3 largest perforators, which were marked radiologically (arrows), have been cut
out of the acetate by using a 3.0-mm biopsy punch (Stiefel Laboratories Inc., North
Carolina, USA).
Fig. 3 Preoperative marking process
The 'punched' acetate is laid onto the abdomen, also marked pre-operatively from sternal
notch to pubic symphysis, carefully centred at the umbilicus and lined up with the
patient's midline. The perforator sites are marked directly onto the abdomen through
the punched holes.
Fig. 4 Completed preoperative marking
After acetate removal, the most suitable perforator is quickly selected using a hand-held
Doppler in preparation for surgery.
DISCUSSION
Preoperative DIEP perforator marking is currently undertaken using CTA reports of
2 vector distances from the umbilicus. These distances are measured directly onto
the patient. This marking process may be time-consuming, particularly when multiple
perforators exist. Furthermore, 'mapping errors' may occur due to errors in observation,
transcription and interpretation. The use of templates in breast reconstruction has
been shown to be a simple, efficient and cost-effective way to increase preoperative
marking accuracy, reduce theatre time and improve outcomes, having previously been
used for the reconstruction of the infra-mammary fold and breast mound planning with
DIEP flap reconstructions [3],[4].
We have found this template technique to be easy to use and reproducible; further,
it improves the accuracy and efficiency of preoperative marking for patients undergoing
DIEP flap breast reconstruction.
