Type:
Educational Exhibit
Keywords:
Head and neck, CT, MR, Treatment effects, Complications, Education and training
Authors:
M. Javier1, J. A. Guzman de Villoria2; 1 Madrid/ES, 2Madrid, Ma/ES
DOI:
10.1594/ecr2013/C-1042
Imaging findings OR Procedure details
Classification:
Flaps are classified based on the integrity of their vascular supply into either free or pedicled and are used for closing large surgical defects after resection of advanced malignant tumors
It is possible to differentiate both type by recognizing the arteriovenous vessels running along the long axis of the rotated bulk of muscle in pedicled flaps (fig.
3),
while free myocutaneous flaps appear as a soft-tissue mass composed mostly by fat that was transferred from one anatomic location to another (fig.
1).
Free osteomyocutaneous flaps (or microvascular tissue transfers) are taken from a distant anatomic site along with its vascular pedicle and then are anastomosed into the soft-tissue defect using microsurgical techniques.
Rectus abdominis and latissimus dorsis muscles are often used as microsurgical or free flaps to cover large defects in anterior neck or cheek area (fig.
2).
Free flaps can also contain vascularized bone such as fibula which is frequently used for mandibular reconstruction (fig.
4).
Other frequent donor sites in reconstruction of mandibulectomy defects include scapula and iliac crest.
The trapezius,
pectoralis major and temporalis are the three most commonly used pedicled rotational flaps in head and neck surgery.
This type of flap preserves their arterial and venous vascularization and is rotated into the defect.
The temporalis muscle is usually used in skull base reconstruction (fig.
5A).
Postoperative complications.
The first imaging findings that strongly suggest tumor recurrence or infection is the obliteration of fat tissue planes,
striation or nodular mass that was not present on baseline postoperative CT or MR studies (fig.
6 and fig.
7).
In case of absence of previous comparison studies the radiologist should keep in mind that the presence of some striation in the flap could correspond to degenerating residual muscle fiber.
On the other hand the detection of a nodular mass is almost always a pathological finding that suggests tumor recurrence,
presence of abscess or a large necrotic lymph node.
It is has been demonstrated by many authors that the majority of myocutaneous flaps show some degree of enhancement on fat suppressed contrast enhanced MR images that should not be mistaken for malignancy recurrence or tumor extension.
Other complications that usually do not require imaging and are clinically diagnosed,
but should be suspected in a proper clinical setting,
include vascular thrombosis,
hematoma,
seroma and fistula tracts.