Sphenoid Sinus Fat Packing in Transsphenoidal Surgery: Long-Term Fate Assessment Using Magnetic Resonance Imaging

ABSTRACT

Background and Objectives@#Following the transsphenoidal approach (TSA), appropriate sphenoid sinus fat packing has been preferred to prevent postoperative cerebrospinal fluid leakage; however, studies on the behavior of fat tissue transplanted in the sphenoid sinus are lacking. This study aimed to determine the long-term fate of these fat grafts using magnetic resonance imaging (MRI).Subjects and Method: A total of 139 postoperative MRI scans of 41 patients who underwent sphenoid sinus fat packing using the standard TSA were evaluated. Additionally, MRI time series indicating the vital fat volumes were assessed postoperatively. @*Results@#In 82.9% of cases, the fat volumes measured in the final MRI scans declined to 60% of the initial volume. The fat tissue volume decreased significantly with time, with a median half-life of 18 months. Typically, the sphenoid sinus was eventually almost filled with air rather than transplanted fat. In the subgroup analysis, the fat clearance rate was significantly lower in patients with residual tumors than in those without such remnants (p=0.013). @*Conclusion@#Long-term MRI surveillance of fat grafts in the sphenoid sinus revealed that the transplanted fat graft had degraded and was gradually eliminated.