The Use of Composite Cartilagomucosal Nasoseptal Flap for Skull Base Reconstruction after Resection of a Suprasellar Mass

Introduction: The nasoseptal flap (NSF) is the main reconstructive option in endonasal skull base surgery. This reliable reconstruction is effective to seal cranial base defects and avoid CSF leak. However, the bone removal resultant from the approach is not replaced with this technique. Here we present a novel technique based on semi-rigid reconstruction that can be used not only to prevent CSF leak but also to reinforce and protect the intracranial structures. The composite cartilagomucosal NSF is designed leaving part of the quadrangular cartilage of the septum attached to the mucosal flap. This extra strength obtained with the cartilage may be interesting to protect important neurovascular structures, particularly in young patients where medical nasal intrusion may be necessary.

Case Report: The patient is a 17-year-old female who presented with primary amenorrhea. Images showed a suprasellar mass. It showed a lobulated mass within the suprasellar cistern with extension into the floor of the third ventricle that measured 16 × 8 × 12 mm. No other acute intracranial findings were noted. Preoperative laboratories showed hyponatremia and decreased pituitary hormones consistent with hypopituitarism. The patient's suprasellar mass showed reactive lymphoid hyperplasia; the pituitary gland was infiltrated by lymphocytes, resulting in impaired hormone release.

Surgical Technique: After the regular incisions for the NSF are performed, the anterior edge of the flap, next to the caudal border of the septum is carefully elevated. This elevation is carried posteriorly up to ~5 mm of the incision. Superiorly, next to the nasal dorsum incision, the mucosa is elevated from the cartilage only ~5 mm from the nasal dorsum. The goal is to expose an “L” strut to support the septum and leave the mucosa of the center of the quadrangular cartilage still attached. At that point, the septal cartilage is transected parallel to the caudal border of the septum and parallel to the nasal dorsum. Then the cartilage is elevated from the contralateral mucosa in a subperichondrial plane until identification of the perpendicular plate of the ethmoid posteriorly and the maxillary crest inferiorly. At that point, the cartilage is detached from those two structures and the harvest continues on the initial side as usual for the NSF with the elevation of the mucosa from the vomer. At the end, the NSF will have a piece of septal cartilage attached to it. After the tumor was resected with a transplanum/transtuberculum approach, the high flow intraoperative CSF leak was reconstructed with inlay/onlay fascia lata button graft and onlay composite cartilagomucosal NSF.

Results: Patient is 4-months out from surgery. No postoperative CSF leak. No complications related to the composite flap. Nasal endoscopy in clinic shows the flap well healed to the cranial base but no pulsation due to transmission of brain pulsation as usually seen with the regular NSF.

Conclusions: The reconstruction of a suprasellar defect with a composite cartilagomucosal NSF was feasible. No complications related to the flap were noticed. Further surgical cases and longer follow-up are needed for a better assessment of the benefits of this technique.