Osteoma involving the olfactory groove: evaluation of the risk of a CSF leak during endoscopic surgery

PURPOSE: The olfactory groove (OG) is a common site of iatrogenic cerebrospinal fluid (CSF) leak during endoscopic sinus surgery. We aimed to evaluate the prevalence of CSF leak during endoscopic removal of osteomas involving the OG and identify CT findings indicating increased risk of this complication. METHODS: A retrospective review was conducted of patients operated on for frontoethmoidal osteoma from 11 years in a single institution. A retrospective review of the literature, 1999 to 2019, of perioperative complications in patients operated on for frontoethmoidal osteoma using endoscopic or combined approaches. RESULTS: Case series: 73 patients were identified including 17 with the OG involvement. The only case of CSF leak occurred in a patient with spongious part of osteoma at the OG. Among six osteomas with spongious component at the OG, one was detached and five had to be drilled down, leaving a small remnant in four. In contrast, all the 11 osteomas with ivory part at the OG were safely detached and completely removed from the OG after debulking. The prevalence of CSF leak was not statistically different between the patients without and with involvement of the OG. Systematic review of the literature: Among the 273 identified patients there were 8 cases of intraoperative CSF leaks (3%) including 2 from the OG (0.7%). CONCLUSION: Involvement of the OG does not significantly increase the risk of intraoperative CSF leak. However, this risk may be increased in patients with the spongious part of the tumor attached to the OG.