Surgical Navigation and Mirror Image Overlay: A Novel Approach for Orbital Reconstruction after Skull Base Tumor Resection

Background Reconstruction of the orbit after skull base tumor resection represents a unique clinical challenge, as these patients are at greater risk for postoperative ocular and vision complications given the extensive resections undergone. Intraoperative CT navigation using mirror image overlay guidance is a novel approach to aid reconstruction for this patient population.

Objectives To describe the use of intraoperative CT navigation using mirror image overlay guidance in the reconstruction of orbital defects after resection of complex skull base tumors.

Methods Case series of five patients who presented with skull base tumors invading into or originating from the orbit, all requiring extensive resection and orbital reconstruction. In each case, iNtellect Cranial Navigation (Stryker Corp) was used to preoperatively virtually reconstruct a mirror image overlay of the patient's craniofacial structures from the surgically unaffected side using CT imaging (0.6−1.25 mm cuts). This overlay was loaded into the navigation computer, and endoscopy was utilized with the navigation to compare position and conformation of the reconstructive orbital implant relative to the mirror image overlay (Image 1).

Results Patient ages ranged from 20 to 75 years. The tumor pathologies represented included a ghost cell tumor, two esthesioblastomas, an osteosarcoma, and a vascular malformation. Four of five patients had already undergone previous surgical management for skull base tumor resection. Of the four patients with postoperative CT scans available for review, all were confirmed to have highly symmetric orbital reconstructions. Six months postoperatively, four of five patients had either significant improvement in diplopia or never developed postoperative diplopia from preoperatively normal baseline vision. The remaining patient had stable diplopia after reconstruction. Three patients had hardware extrusion within 2 years postoperatively, requiring hardware removal; all three had received postoperative radiation. Of these, one patient suffered tumor recurrence and required additional surgical management for tumor removal, for which mirror image overlay technique was again used.

Conclusion CT navigation with mirror image overlay represents an innovative approach to address orbital reconstruction in patients with skull base tumors that invade the orbit. In this case series, four of five patients had significant improvement in diplopia or no change in baseline normal vision, and one patient maintained stable diplopia. All postoperative CT scans available for review confirmed highly symmetric orbital reconstructions. Prospective studies are needed to determine how this technique compares directly to current methods of reconstruction without advanced navigation.

Fig. 1

Publication History

Publication Date:
02 February 2018 (online)