Clival dural reconstruction via transnasal approaches: fat graft fixation technique

CSF fistulas are the weak spots of transnasal endoscopic and microsurgical skull base approaches. An autologous fat graft is considered the best substrate for clival dural reconstruction via transnasal approaches. However, potential gravitational displacement of the graft may result in CSF leakage. The authors have developed and described herein the fat graft fixation (FGF) technique to secure the fat graft against dislocation after transclival resection of chordomas invading the dura.

Seventy-five patients with cranial chordomas underwent surgical treatment at the authors' institution from September 2006 through June 2023. Of these, the authors collected demographic, clinical, radiological, surgical, and outcome data from 34 patients who underwent an endoscope-assisted microsurgical transclival approach via a transnasal, sublabial, or sublabial transmaxillary extended corridor. The FGF reconstruction technique was progressively implemented to improve clival reconstruction, with a focus on the results. With a custom-made 8-mm 3/8 round atraumatic surgical suture needle, a 4/0 Vicryl stitch was placed through the adjacent dural borders. An abdominal autologous fat graft was then placed over the dural defect. One triple knot was tied to secure the graft and prevent its delayed gravitational displacement. The primary outcome was to determine if the FGF group had a higher rate of early or late oronasal CSF fistula compared to the unlocked free graft group. Secondary outcomes included tension pneumocephalus, surgical site infection, and meningitis.

The fat graft was not used in 8 (23.5%) of the 34 patients because the dura was intraoperatively intact. The unlocked free graft and FGF techniques were used in 20 (58.8%) and 6 (17.6%) patients, respectively. Of the 34 patients, no fistulas were observed in the group treated with the FGF technique, while 4 fistulas were found in the unlocked free graft group (p < 0.05), with 2 of these cases involving meningitis. Patients with a CSF fistula underwent a total of 7 surgical procedures: 3 revision surgical procedures, 2 lumboperitoneal shunts, and 2 ventriculoperitoneal shunts.

In the authors' preliminary experience, the FGF technique has shown promise in eliminating the risk of CSF fistula and other related complications after the transclival approach for clival chordomas involving the dura.