Salvage Vastus Lateralis Free Tissue Transfer for Postoperative CSF Leaks after Multiple Redo-Surgeries and Proton Beam Radiotherapy for Clival Chordoma

Case report of a 56-year-old patient who was suffering from chronic headaches and tongue deviation to the right. A Cervical MRI showed a well-defined lesion at the craniocervical junction compatible with chordoma. He underwent several surgeries and received two rounds of Proton Beam Radiotherapy. Because of that, the patient suffered from osteonecrosis of the skull base and CSF leak more than one year after the first surgery. Skull base reconstruction using vastus lateralis free tissue transfer was used after failed multiple trials to seal the defect using local vascular flap and fat graft. Vascular free flaps are preferred over local or regional flaps in the reconstruction of skull base defects (secondary to postradiotherapy osteonecrosis), since radiotherapy compromises the vascularity of local and regional flaps. More than 6 weeks after the surgery, at the rhinoscopy, we could notice the surrounding mucosa in-growing into the flap and no sign of CSF leak.

We described the technique (from free flap harvest till its insertion inside the nose, to stop the CSF leak) with the pictures of the main moments

Fig. 1 (A) Axial T2-weighted MRI showing an intracranial chordoma with heterogeneous but mainly high signal in the lower clivus. (B) Mild contrast-enhancing of the tumor in the lower clivus at T1-weighted sagittal view. (C) Sinuscopy, showing an expansive lesion at the topography of the clivus. (D) CT axial view showing pneumocephalus causing compression of the frontal lobes.

Fig. 2 Transcervical retropharyngeal tunneling and placement of the ALT free flap. (A) standard submandibular cervical incision with retractor medializing the pharynx. (B) Endoscopic view of transcervical approach. (C) Retropharyngeal approach into the necrotic nasopharynx. Note the extensive necrosis visible in through the access. (D) Zero-degree endoscopy showing the panoramic view of the retropharyngeal approach to the nasopharynx. (E) Endoscopic, endonasal view of the ALT flap being tunneled into the nasopharynx. (F) Fascia lata of the ALT in the nasopharynx. Due to its vascularity, the muscular surface was placed against the necrotic skull base.

Fig. 3 (A, B) A small piece of vascularized anterolateral thigh flap was harvested measuring 10 cm × 3 cm with a long pedicle length. (C). Facial artery was anastomosed to the descending branch of the circumflex femoral artery.

Fig. 4 Evolution of the free flap healing. (A) intraoperative placement of the ALT flap with Nasopore centrally opposing the flap into the clival recess. (B) One week postoperative view of the flap with excellent vascularity and granulation tissue after debridement in the office. (C) Six weeks postoperative examination of the flap. Notice the arrow pointing to the surrounding mucosa ingrowth into the flap. (D) Panoramic view of flap at 6 weeks postoperative.

In conclusion, Microvascular free flaps are better alternatives (than local and regional flaps) for the reconstruction of skull base defects in patients with skull base tumors who underwent surgery and received Radiotherapy. Skull base reconstruction using vastus lateralis free tissue transfer is a good option for the repair of middle skull base defects secondary to osteoradionecrosis