Goals of cranioplasty include protection of intra-cranial content and dural repair as well as re-establishment of pre-operative cosmesis. Alloplastic materials are often used to correct calvarial defect but have a lower success rate when used in a radiated field. Failures may present as a chronic fistula draining cerebrospinal fluid, osteomyelitis of the calvarium, brain abscess, meningitis or seizures. The hypocellular, hypovascular and hypoxic environment produced by radiation therapy offers a challenge to the reconstructive surgeon. Microvascular tissue transfer is the ideal therapeutic measure in this patient population. Furthermore, in large areas where the dura is exposed, a free flap is a durable reconstruction and can also aid in enhancing dural repairs. We are presenting five cases where six free flaps were used to reconstruct failed alloplastic cranioplasties following radiation therapy. In two of those cases, the flaps were used in conjunction with a titanium mesh cranioplasty. Three radial forearm free flaps were used, two of which were in the same patient who had a recurrence of his malignancy. We used the latissimus dorsi flap on two occasions, while the last patient was treated with a serratus anterior flap. Complete coverage of the wound was obtained in all patients without long term complication.

The latissimus dorsi is an expendable muscle which provides a free flap with a very long dominant vascular pedicle. This allows for the microvascular anastomosis to be performed outside the radiated field. If needed, the anastomosis can be carried at a lower level without the need for an interpositional vein graft. Furthermore the latissimus dorsi free flap provides a good volume of muscle, able to cover large defect and protect a dural repair. The radial forearm flap provides an excellent choice for small defects where there is no need for osseous reconstruction. The thickness of the forearm flap is comparable to normal scalp. Therefore there is no excessive bulkiness. The serratus anterior flap can provide vascularized muscle and bone, if needed, on a single long vascular pedicle. Our results indicate that microsurgical free flap transfer allows for immediate, single stage coverage of wound previously radiated with well-vascularized tissue. We will discuss in further details our strategy in flap selection as well as our treatment planning algorithm used in this specific patient population.