The role of MR and endoscopy in postoperative management of skull base reconstruction by vascular pedicle septal flap

Abstract

To explore the significance of MR and endoscopy in the postoperative management of skull base reconstruction with a vascular pedicle nasoseptal mucoperiosteal flap. The immediate, and delayed postoperative MR imaging scans and endoscopic data of 8 patients who underwent endonasal endoscopic reconstruction of skull base dural defects with a vascular pedicle nasoseptal mucoperiosteal flap were retrospectively studied. Among the 8 patients, 7 cases have integrated immediate, delayed postoperative MR and synchronous endoscopic data which were harvest at the first week and at a 3- to 7-month interval respectively. One case was followed up by CT and endoscopy. The intracranial parenchymal changes, local situation of skull base defect site, the septal flap, healing of flap donor site and the transition of naso sinus mucosa were fully evaluated to explore the healing process and to improve the success rate of the reconstruction. We can obtain the key postoperative information of intracranial and the skull base reconstruction site with MR and endoscopy. The MR can exclude the intracranial complications such as postoperative intracranial hematoma, cerebral edema, or pneumocephalus, and clearly show the location and extent of skull base defects, the position of the flap, the overlapping manner between the dural defect margin and the flap and the postoperative cerebrospinal fistula. In immediate and postoperative follow-up with MR, the septal flap had homogeneous enhanced image with a roughly "C" figure under the skull base, indicating stable blood supplement. The synchronous endoscopic examination also proved the survival of the septal flaps in 7 cases , the cerebrospinal fluid leakage in 1 case. One case flap necrosis. The septal flaps presented edema and congested in the immediate postoperative endoscopy, and returned to normal in the delayed examination. The non-vascular materials such as gelatin sponge and fat tissue had the different characteristics signal. Nasal mucosal edema and sinus ventilation continually recovered during the follow up and the exposed septal cartilage on the donor site resurfaced by mucosa in 2 months. MR and endoscopy could provide the critical postoperative information about the vascular pedicle septal flap reconstruction. MR combined with endoscopy not only could rule out the complications, but also could gain the information such as the position, blood supply and healing of the flap, at the same time detected the cerebrospinal fluid leakage to provide accurate information for the secondary stage reconstruction. The information got from MR and endoscopy were important for the surgeon and the radiologist to recognize the flap and to evaluate for variations that may suggest potential flap failure.