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Page 4 of 9 Swendseid et al. Plast Aesthet Res 2021;8:41 https://dx.doi.org/10.20517/2347-9264.2021.47

area. Orbital exenteration, resection of the orbital roof, floor, rims, and violation of the paranasal sinuses are
[13]
common. Exenteration results in dural exposure in 20%-30% of cases and CSF leak in up to 16% of cases .
Small ASB defects can often be closed with local flaps such as a pericranial or TPFF. Larger defects may
require either bony or soft tissue flaps based on the reconstructive goals. The traditional skull base
workhorse free flap, rectus abdominus, has largely fallen out of favor and is often replaced in the algorithm
with a radial forearm (RFFF) or anterolateral thigh (ALTFF) flap [14-18] .

Orbital exenteration cavities with intact periorbital bone can be reconstructed with soft tissue-free flaps. A
thinner flap such as an RFFF maintains the concavity of the orbital cavity, facilitating the postoperative use
of an orbital implant. However, these thinner flaps may be more susceptible to radiation contracture and
[19]
the development of orbitocutaneous fistula . Bulkier flaps such as an ALTFF or a parascapular system flap
with serratus or latissimus muscle (SFF) can be used to slightly overfill the exenteration cavity to account for
some expected contracture and can provide some additional support to the skull base closure [Figure 2]. A
skin paddle can be used externally for immediate closure of the wound; however, using a muscle flap
without a skin paddle produces a superior skin match after re-epithelialization.

For patients who are candidates for orbital preservation, it is common to retain orbital function (98% in one
series), although some degree of impairment such as ectropion is common (40% of patients), particularly
when adjuvant radiation is employed. Therefore, revision surgery is often required for the management of
orbital sequelae in this setting. However, it is rare for a delayed exenteration to be required unless tumor
recurrence occurs .
[20]

Careful attention to the paranasal sinuses can prevent future complications. Exenteration, maxillectomy,
and anterior skull base resection will expose the paranasal sinus contents to the surgical site, skull base, and
extradural spaces. Reconstruction should aim to re-establish the separation between the contaminated
paranasal sinuses and the rest of the wound. Figure 3 demonstrates the many potential pitfalls in free flap
reconstruction of these defects. High volume flaps can obstruct natural sinus drainage, such as the frontal
outflow tract. As such, when the frontal sinus is violated, care must be taken to remove all sinus mucosa to
prevent mucocele formation. Patients are undergoing radiation experience sinus inflammation and
[21]
deficiencies in mucociliary clearance . One should consider performing sinus surgery in the primary or
secondary setting for these patients, which helps assist in monitoring for local recurrence and also prevents
the sequela of post-radiation sinusitis. A Rains stent can be placed in the frontal outflow tract to prevent
scarring during radiation treatment .
[22]

Low volume flaps risk nasocutaneous fistulas, which can occur due to numerous factors, including contact
with contaminated paranasal sinuses, the effects of gravity, and adjuvant radiation therapy. There is an
increasing likelihood of fistula with a greater extent of violation of the nasal and paranasal sinus cavities.
Commonly, these occur in the superior and medial portions of the orbit. In a series of mostly ALTFFs, a 9%
fistula rate was seen, and in each fistula case, the medial orbital wall or ethmoid sinuses were involved in the
resection. Careful attention to these areas during reconstruction by obliterating dead space and properly
securing the flap to remnant bony anatomy may avoid this complication, which often requires a second free
[19]
flap for correction .
With the upsloping nature of the ASB, reconstruction must consider the effect gravity will have on the flap.
Simply suturing a large soft tissue flap superiorly could result in dehiscence and CSF leak as gravity exerts
downward pressure on the tissue bulk. Instead, small holes may be drilled into the calvarium, which can be
used to suspend the flap . Alternatively, a bone segment from an osteocutaneous radial forearm or
[2]