Reconstruction of Large Anterior Cranial Base Defects with Cutaneous and Orbital Involvement

Background: The defects from resection of anterior skull base masses will often require reconstruction with vascularized pedicle flaps and sometimes free flaps. Prior reports show the use of a combination of flaps, when a single flap cannot adequately access, cover and support the entire defect. Reconstruction of these defects becomes more complex when there is orbital and cutaneous involvement. The aim of this study is to present a series of four consecutive patients treated for large anterior skull base and facial defects with a combination of grafts, pedicled and/or free flaps.

Methods: Between June 2016 and March 2018, four patients with invasive malignant tumors involving skin, subcutaneous tissue, sinuses, anterior skull base with dural and/or orbital involvement underwent radical resection including orbital exenteration in some cases. Operative techniques for reconstruction included collagen dura matrix and fascia lata graft, nasoseptal flap, pericranial flap, paramedian forehead flap, temporalis muscle flap and/or vastus lateralis musculocutaneous free flap. Patients’ charts were reviewed to assess complications and outcomes.

Results: Patient ages ranged from 26 to 88: three males, one female. Invasive tumors included two cases of squamous cell carcinoma, one chondrosarcoma and one sinonasal undifferentiated carcinoma.

All cases had significant cutaneous involvement and consequent large defects after the resection. In two cases this was reconstructed with local advancement and paramedian forehead flap and two cases with vastus lateralis musculocutaneous free flaps. In one case, there was a defect in the ascending process of the maxilla reconstructed with a titanium plate.

Three cases required orbital exenteration. In two cases this defect was reconstructed with a temporalis muscle flap. In all cases resection at the anterior cranial base included dura. Three cases were reconstructed with collagen dura membrane grafts, one case with fascia lata graft. In three cases, further reconstruction included a pericranial flap. In one of these cases a nasoseptal flap was used to reconstruct the posterior aspect of the defect. In another, the pericranial flap was layered and sandwiched a layer of fascia lata to provide additional support.

One patient developed a CSF leak through the skin on postoperative day two which was repaired by reinforcement with fat grafting over the pericranial flap. Two patients developed nasal cutaneous fistulas following radiation therapy (one patient had local flaps only and the other patient had free flap reconstruction). In the local flaps only case, this was in the region of the titanium plate. One patient incurred a traumatic abrasion to the skin of the vastus lateralis free flap which was repaired with a split thickness skin graft during revision. One patient with squamous cell carcinoma experienced disease recurrence on follow-up PET-CT 8 months postoperatively. The patient with chondrosarcoma was found to have disease recurrence ten months postoperatively on CT head.

Conclusion: Large anterior cranial base defects with orbital and cutaneous involvement present a significant challenge in reconstruction requiring multiple pedicled and/or free flaps. The reconstruction is individual in such populations of patients with advanced disease and poor prognosis. Minimizing morbidity associated with reconstruction should be prioritized in the overall treatment plan.

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