Introduction: The use of free fat graft is a widely applied technique in skull base surgery for reconstruction of basal dural defects. However, graft integration into CSF spaces, dural repair strength and evolution of graft size in postoperative period has not been sufficiently studied. The goal of this study is the analysis of the results of free fat graft usage.

Methods: At the beginning of our research there was an experiment with the purpose to investigate the principles of early graft integration and to evaluate watertight durability closure. Fat and fascial grafts at dural reconstruction were compared. Then histomorphological study was conducted. The clinical part included 450 patients with different skull base tumors. The mean age was 43.4 (29-80 years). Fat grafts were used to occlude the defects: sphenoid sinus, ethmoid sinus, mastoid air cells. MRI was performed in 7 days after operation and in the long-term after it. Graft size and MRI signal intensity were measured. The mean follow-up was 74 months (12-120 months).

Results: Experimentally fat graft provides the most watertight durability closure compared with fascial graft. Histological study showed complete physical graft integration in 1 day after surgery; beginning of vascularization – in 7 days; complete biological graft integration – in 14 days. Serial MRI study showed the mean graft size reduction to 71.6% after 1 month; to 38.3% after 3 years and 35.9% after 10 years. 7.8% of patients had fibrous graft transformation, 1.1 % - graft lysis, 0.4% – graft infection. There were no cases of lipoid meningitis detected. The rate of CSF leak was 2%. All cases of CSF leak were noticed in the first 5 days after surgery.

Conclusions: Fat graft serves as an effective dural watertight closure and helps to decrease CSF leak rate. Analyzing the fate type of fat graft we can speak of natural and complicated evolutions. Natural evolution can be typical and atypical. Typical evolution provides complete biological graft integration. Atypical evolution is fibrous graft transformation or graft lysis.

Patient Care: Fat graft serves as an effective dural watertight closure and helps to decrease CSF leak rate

Learning Objectives: the analysis of the results of free fat graft usage.

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