# Predictors, Complications, and Clinical Outcomes of Cerebrospinal Fluid Leak Post Endoscopic Endonasal Skull Base Surgery

## TL;DR

This study finds that higher BMI increases the risk of cerebrospinal fluid leaks after skull base surgery, while using a vascularized flap reduces it, leading to better outcomes.

## Contribution

Identifies BMI and reconstruction type as key predictors of CSF leaks after EES, with clinical implications for surgical planning.

## Key findings

- Higher preoperative BMI significantly increases the risk of postoperative CSF leaks.
- Using a nasoseptal flap for reconstruction significantly reduces the incidence of CSF leaks.
- CSF leaks are associated with longer hospital stays, higher readmission rates, and increased postoperative complications.

## Abstract

Background: Postoperative cerebrospinal fluid (CSF) leakage remains a significant complication following endoscopic endonasal skull base surgery (EES), leading to increased morbidity. This study aimed to identify factors and interventions predicting postoperative CSF leaks after EES for intradural skull base tumors and their clinical outcomes. Methods: We retrospectively reviewed data from 542 patients who underwent EES for intradural skull base pathology at the Ottawa Hospital between October 2001 and October 2023. Patient demographics, pre-operative, intraoperative (including reconstruction type), postoperative data, and patient outcomes were collected. Results: A total of 40 patients (7.4%) developed a postoperative CSF leak. The highest rate was in patients with suprasellar lesions (5.9%), followed by anterior cranial fossa lesions (1.1%). Significant predictors included a higher mean Body Mass Index (BMI) (30.4 vs. 26.1, p = 0.001). The use of a nasoseptal flap for reconstruction was associated with a significantly lower incidence of CSF leaks (p = 0.001). Tumor location, approach type, and dural sealants were not independent factors for the development of CSF leaks. Patients with CSF leaks had significantly longer lengths of stay (16.7 vs. 9.21 days, p < 0.001), higher 30-day readmission rates (p < 0.001), and increased postoperative sepsis (p = 0.021) and diabetes insipidus (p < 0.001). Conclusion: This retrospective study shows that higher preoperative BMI is associated with a significant risk of postoperative CSF leaks after EES. Conversely, using a pedicled vascularized flap reduces the risk. Postoperative CSF leaks are linked to increased morbidity, including diabetes insipidus and sepsis, prolonged hospitalization, and higher readmission rates.