Invagination of the Sphenoid Sinus Mucosa after Endoscopic Endonasal Transsphenoidal Approach and Its Significance

Sphenoid Sinus Mucosal Flap after Transsphenoidal Surgery-A Systematic Review

Background and Objectives: Skull base reconstruction is a crucial step during transsphenoidal surgery. Sphenoid mucosa is a mucosal membrane located in the sphenoid sinus. Preservation and lateral shifting of sphenoid mucosa as sphenoid mucosal flap (SMF) during the transsphenoidal exposure of the sella may be important for later closure. This is the first systematic review to evaluate the utility of sphenoid mucosal flap for sellar reconstruction after transsphenoidal surgery. Materials and Methods: A systematic literature search was performed in January 2023: Cochrane, EMBASE, PubMed, Scopus, and Web of Science. The following keywords and their combinations were used: "sphenoid mucosa", "sphenoid sinus mucosa", "sphenoid mucosal flap", "sphenoid sinus mucosal flap". From a total number of 749 records, 10 articles involving 1671 patients were included in our systematic review. Results: Sphenoid sinus mucosa used to be applied for sellar reconstruction as either a vascularized pedicled flap or as a free flap. Three different types of mucosal flaps, an intersinus septal flap, a superiorly based flap and an inferiorly based flap, were described in the literature. Total SMF covering compared to partial or no SMF covering in sellar floor reconstruction resulted in fewer postoperative CSF leaks (p = 0.008) and a shorter duration of the postoperative lumbar drain (p = 0.003), if applied. Total or partial SMF resulted in fewer local complications (p = 0.012), such as fat graft necrosis, bone graft necrosis, sinusitis or fungal infection, in contrast to no SMF implementation. Conclusions: SMF seems to be an effective technique for skull base reconstruction after transsphenoidal surgery, as it can reduce the usage of avascular grafts such as fat along with the incidence of local complications, such as fat graft necrosis, bone graft necrosis, sinusitis and fungal infection, or it may improve the sinonasal quality of life by maintaining favorable wound healing through vascular flap and promote the normalization of the sphenoid sinus posterior wall. Further clinical studies evaluating sphenoid mucosal flap preservation and application in combination with other techniques, particularly for higher-grade CSF leaks, are required.

Endoscopic Skull Base Repair Strategy for CSF Leaks Associated with Pneumocephalus

Background: Cerebrospinal (CSF) fluid leaks with associated pneumocephalus (PNC) represent a condition bearing serious risks for the patient, with little data available in the literature. Reported success rates of endoscopic skull base repair are lower when PNC is associated than in the case of simple CSF leaks. The present study represents an analysis of our experience with endoscopic management of this condition. Methods: Records of patients with pneumocephalus and associated CSF leaks, who underwent endoscopic skull base repair, were reviewed. Demographics, history, etiology of PNC, size of defect, surgical approach, reconstruction technique and complications were evaluated. Results: Twenty patients with CSF leaks and PNC underwent endonasal repair by the senior author between 2005 and 2019. Defect size was larger than 15 mm in all cases. All patients presented either worsening of PNC under conservative treatment or tension PNC. First-attempt closure of the defect was successful in all patients (100%), with resolution of the pneumocephalus. One patient developed a synechia in the proximity of the frontal ostium, as a postoperative complication. The mean follow-up was 39 months (range: 15–94 months). Conclusion: The present study represents a proposed argument for earlier endoscopic endonasal treatment in patients presenting CSF leaks and pneumocephalus.

Unexpected prominent tension pneumosella five years after endoscopic endonasal transsphenoidal surgery

Tension pneumosella (TP) is a rare entity reported as the invagination of the sphenoid sinus mucosa into the skull base after endonasal transsphenoidal surgery. Few studies have reported on TP, and in these studies, invagination is confined to either the intrasellar or suprasellar area. We encountered a case of unexpected prominent TP toward the intracranial space 5 years after endoscopic endonasal transsphenoidal surgery (EETS) for a nonfunctioning pituitary adenoma. In addition, we present a hypothesis of the underlying mechanism by a pressure gradient change between the extracranial and intracranial space in TP formation. For repair, a pedicled nasal septal flap was fabricated from the remaining part of the septal mucosa, and a pedicled inferior turbinate flap was created. Moreover, the nasal septal cartilage was used as a rigid support for reconstruction, which was useful for preventing TP recurrence. This is the first report of an unexpected prominent TP after EETS. It is important for otorhinolaryngologists and neurosurgeons to be aware of the possibility of TP following EETS. Laryngoscope, 1798-1801, 2018.