Imaging of Surgical Free Flaps in Head and Neck Reconstruction

Abstract

Head and neck surgical reconstruction is complex, and postoperative imaging interpretation is challenging. Surgeons now use microvascular free tissue transfer, also known as free flaps, more frequently in head and neck reconstruction than ever before. Thus, an understanding of free flaps, their expected appearance on cross-sectional imaging, and their associated complications (including tumor recurrence) is crucial for the interpreting radiologist. Despite the complexity and increasing frequency of free flap reconstruction, there is no comprehensive head and neck resource intended for the radiologist. We hope that this image-rich review will fill that void and serve as a go to reference for radiologists interpreting imaging of surgical free flaps in head and neck reconstruction.

Fig 1.

Flaps based on donor location with respect to the primary defect.

Fig 2.

Rectus abdominis FF. Postoperative coronal CECT in a patient with T4bN0M0 basaloid carcinoma and recurrence after initial partial maxillectomy demonstrates the bulky rectus abdominis FF (block arrow) filling the left midface defect following orbital exenteration and total maxillectomy. The rectus muscle (thin arrow) lines the skull base defect, while a portion of the skin paddle recreates the oral cavity mucosal surface (curved arrow).

Fig 3.

Latissimus dorsi FF. Following total glossectomy, right oropharyngectomy, and total laryngectomy for T4a squamous cell carcinoma (SCC) of the right oral tongue, the FF was harvested and set on the operating room back table (A) with the elongated vascular pedicle (arrowhead), skin (block arrow), and latissimus (arrow). The latissimus is fastened to secure the mandible and recreate the mylohyoid sling. Immediate postoperative picture (B) shows the skin paddle (block arrow) closing the glossectomy defect.

Fig 4.

Radial forearm FF. Intraoperative photo (A) shows the radial artery (arrows) up to the skin paddle (asterisk) after Doppler mapping. Postoperative clinical picture (B) demonstrates the well-incorporated mature flap (double asterisks) following marginal mandibulectomy.

Fig 5.

Tubed radial forearm FF. The diagram (A) shows that free flaps can be partially rolled (upper right) or completed tubed (lower right) to reconstruct the upper aerodigestive tract. Postoperative sagittal CECT (B) following base of tongue hemiglossectomy and laryngopharyngectomy shows the radial forearm FF reconstruction (long arrow).

Fig 6.

Anterolateral thigh FF. Axial fat-saturated T1 postcontrast MR imaging (A) demonstrates the T4a left lateral oral tongue SCC (asterisk), which also involved the extrinsic tongue muscles and floor of mouth. Line drawing (B) of the ALT donor site (outlined) axial anatomy includes the descending branch of the lateral circumflex femoral artery. The ALT has a large, thin, pliable skin paddle with relatively little morbidity at the donor site. ALT FF intraoperative image (C) shows the harvested FF on the operating room back table with an elongated vascular pedicle (arrowhead). Postoperative axial CECT (D), obtained 12 weeks after the operation, shows the inset homogeneous fatty tongue ALT FF (arrow) without induration or edema. The recipient site margins (short arrow) have no nodularity.

Fig 7.

Fibular FF. Preoperative 3D-volume rendered CT (A) demonstrates the T4aN0 right oral cavity SCC (asterisk). Intraoperative photograph (B) (different patient but with a similar reconstruction) shows the surgical plate and bicortical screws used to fixate the inset fibular flap (arrowheads) to the residual native mandible (block arrows). Postoperative 3D-volume rendered CT (C) demonstrates the fibular FF reconstruction (thin arrow) following the right segmental mandibulectomy.

Fig 8.

Scapular osteocutaneous FF. A, Diagram of the scapular donor site (left) and midface inset (right) demonstrates the versatile scapular osteocutaneous FF for complex midface defects. A variety of different bone shapes can be obtained depending on the contour of the defect. One or 2 skin paddles may be harvested; one usually recreates the oral mucosal surface as shown in the diagram. 3D-volume rendered CT (B) in a patient who is status post right maxillectomy shows the lateral scapular border reconstructing the right maxilla and orbital rim (thin arrow), while the scapular tip reconstructs the hard palate (block arrow).

Fig 9.

Jejunal FF. Following laryngopharyngectomy, the intraoperative photograph (A) shows a segment of the jejunum (arrow) interposed between the oropharynx and esophagus, anastomosed end to end to allow patients to eat and swallow. Sagittal postoperative CECT (B) shows the jejunal FF neopharynx (block arrow).

Fig 10.

Osseous FF margins. Axial noncontrast CT shows the expected postoperative appearance (A) following right segmental mandibulectomy and fibular FF reconstruction, with a healing symphyseal interface (thin arrow) and a nonunited-but-sharp osteotomy underlying the posterior mandibular body surgical plate (thick arrow). Axial noncontrast CT of a different patient with a fibular FF shows a complicated postoperative appearance (B), with a nonunited, diastatic, irregular symphyseal margin with a periosteal reaction in this patient with osteonecrosis of the fibular FF and native mandible.

Fig 11.

Expected FF fat and muscle appearance. The postoperative axial CECT (A) following orbital exenteration and latissimus FF reconstruction shows the normal thin musculature (arrow) and fat of the flap. Axial T1 precontrast MR image (B) shows the FF with muscular striations (arrow). The FF fat (curved arrow) deep to the muscular component is homogeneously hyperintense. Axial postcontrast fat-saturated T1 MR image (C) shows the FF muscular thin, non-nodular enhancement (block arrow), similar to that in other muscles in the H&N.

Fig 12.

Tumor recurrence. Preoperative axial CECT (A) shows a T4a maxillary sinus SCC. Following maxillectomy and orbital exenteration with ALT FF reconstruction, the patient had a biopsy-proved recurrence (white arrowheads) at the margins of the ALT FF on postoperative CECT (B) several months later.

Fig 13.

Inflammation. Postoperative T1 axial MR image (A) after reconstruction with a latissimus FF shows hypointense abnormal signal (arrows) and enlargement of the right masseter. Considerations included myositis, denervated muscle, or recurrent intramuscular tumor. Ultrasound-guided biopsy (B) shows good positioning of the needle tip in the muscle (arrowhead). Final pathology results were benign skeletal muscle and fibroadipose tissue, consistent with focal inflammation; no malignant cells were present.

Fig 14.

FF Infection. This patient had fever, elevated white blood cell count, and purulent left neck drainage following radial forearm FF and fibular FF reconstruction for T4aN2c SCC of the right oral tongue. Axial CECT shows an abscess with flap induration, irregular enhancement, and pockets of gas in the right floor of mouth (arrows). Note stranding in the fatty flap (block arrow), compared with the homogeneous fat density in the lateral flap that reconstructed the buccal mucosa (star).

Fig 15.

Hardware exposure. A patient with T4aN0M0 left floor of mouth SCC status post pectoralis rotational flap and surgical bar reconstruction. A fibular FF reconstruction was originally planned but abandoned due to severe peripheral vascular disease. The patient was lost to follow-up for 2 years and then presented with a 1-month history of hardware exposure with a large area of exposed mandibular hardware (arrow) on axial CECT (A) and clinical examination (B).

Fig 16.

Vascular pedicle ossification. A patient with fibular FF following right mandibulectomy for T2N1 SCC of the mandibular gingiva returned 8 weeks after the operation with a palpable right-neck mass. Oblique coronal MIP reconstruction from CECT, bone windows, shows linear ossification (arrows) along the course of vascular pedicle, corresponding to the palpable abnormality.