The 4 F (Fat, Fascia, Fibrin, and Fat) Technique for Skull Base Reconstruction in Endoscopic Transorbital Surgery

Superior eyelid endoscopic transorbital approach (SETOA) has demonstrated broad versatility in addressing heterogeneous lesions involving the paramedian anterior and middle skull base in carefully selected patients. Although various skull base reconstruction techniques have shown promising results in reducing cerebrospinal fluid (CSF) leaks, no standardized method has yet been established that consistently ensures optimal outcomes in the presence of an intraoperative CSF leak to achieve a watertight seal and minimize the risk of potentially life-threatening complications.

Preliminary data from a monoinstitutional surgical series of patients harboring different intracranial lesions, in whom intraoperative CSF leak was detected and who underwent reconstruction during SETOA using a novel method defined "4F", were retrospectively analyzed. The technique consists of intradural autologous fat graft, extradural fascia lata, fibrin glue and extradural autologous fat graft. Postoperative functional and esthetic outcome, particularly reconstruction-related complications, were assessed over a follow-up period of 14-38 months.

The surgical series included 16 patients (2 metastases, 1 orbital lymphoma, 10 meningiomas, 2 trigeminal schwannomas, 1 case of postoperative CSF leak). SETOA was performed in 13 cases, while in the remaining three patients an extended lateral rim orbitotomy variant was added. No cases of CSF leak were observed during the follow-up period. The method provided effective reconstruction, with no instances of major or even minor reconstruction-related complications -such as proptosis, enophthalmos, meningoencephalocele, diplopia, new onset ocular paresis or wound infection-and no revision surgeries were required.

This preliminary experience suggests that the 4F reconstruction technique may be a feasible option for managing osteodural defects during SETOA. It accomplishes the goals of skull base reconstruction, to achieve a watertight closure and avoid dead space. However, given the limited sample size and lack of a control group, definitive conclusions cannot be drawn. Further studies with larger cohorts, standardized outcome measures, and comparative methods are required to assess its final clinical utility.