Adipofascial Radial Forearm Free Flap for Anterior Skull Base Reconstruction in Complicated Forebrain Oncological Surgery

Multilayer Anterior Skull Base Reconstruction with Cortical Rib Bone Graft: Preliminary Experience

OBJECTIVE

During the past decades, different methods have been described for anterior skull base reconstruction. Regarding larger skull base defects, few investigators have described the use of bone grafts to foster support and prevent frontal lobe sagging, herniation, or falling. The aim of this study is to describe the use of a rib bone graft, which could be an option in these cases due to its rigidity and dimensions.

METHODS

We retrospectively collected preoperative, intraoperative, and postoperative data at the last follow-up of 10 patients who underwent multilayer anterior skull base reconstruction, including rib bone graft, for large anterior cranial base defects at 2 tertiary care academic hospitals.

RESULTS

Eight patients underwent endoscopic craniectomy for sinonasal malignancies, and the other two underwent transnasal endoscopic surgery for congenital meningoencephalocele. Anterior skull base defects measured on average 3.8 cm ± 0.9 SD antero-posteriorly (range 2.5-5 cm) and 2.3 ± 0.9 SD latero-laterally (range 0.9-4 cm). Multilayer reconstruction was performed in all cases, including a rib bone graft positioned as intracranial extradural layer. No patient experienced thoracic complications during the postoperative period. No side effects related to the bone graft or meningoencephalocele occurrence were reported after a mean follow-up of 8.0 ± 6.3 months.

CONCLUSIONS

The use of a cortical rib bone graft could be a safe and effective option in skull base reconstruction when managing large defects after cancer removal.

Reconstruction in open anterior skull base surgery: A review and algorithmic approach

PURPOSE

Defects resulting from open resection of anterior skull base neoplasms are difficult to reconstruct. Our objective was to review the literature and describe an evidence-based algorithm that can guide surgeons reconstructing anterior skull base defects.

METHODS

A research librarian designed database search strategies. Two investigators independently reviewed the resulting abstracts and full text articles. Studies on reconstruction after open anterior skull base resection were included. Studies of lateral and posterior skull base reconstruction, endoscopic endonasal surgery, traumatic and congenital reconstruction were excluded. Based on the review, a reconstructive algorithm was proposed.

RESULTS

The search strategy identified 603 unique abstracts. 53 articles were included. Adjacent subsites resected, defect size, radiotherapy history, and contraindications to free tissue transfer were identified as key factors influencing decision making and were used to develop the algorithm. Discussion of the reconstructive ladder as it applies to skull base reconstruction and consideration of patient specific factors are reviewed. Patients with a prior history of radiotherapy or with simultaneous resection of multiple anatomic subsites adjacent to the anterior skull base will likely benefit from free tissue transfer.

CONCLUSIONS

Reconstruction of anterior skull base defects requires knowledge of the available reconstructive techniques and consideration of defect-specific and patient-specific factors.

Anatomic Considerations of Microvascular Free Tissue Transfer in Endoscopic Endonasal Skull Base Surgery

Objective Though microvascular free tissue transfer is well established for open skull base reconstruction, normative data regarding flap design and inset after endoscopic endonasal skull base surgery (ESBS) is lacking. We aim to describe anatomical considerations of endoscopic endonasal inset of free tissue transfer of transclival (TC) and anterior cranial base resection (ACBR) defects.

Design and Setting Radial forearm free tissue transfer (RFFTT) model.

Participants Six cadaveric specimens.

Main Outcome Measures Pedicle orientation, pedicle length, and recipient vessel intraluminal diameter.

Results TC and ACBR defects averaged 17.2 and 11.7 cm2, respectively. Anterior and lateral maxillotomies and endoscopic medial maxillectomies were prepared as corridors for flap and pedicle passage. Premasseteric space tunnels were created for pedicle tunneling to recipient facial vessels. For TC defects, the RFFTT pedicle was oriented cranially with the flap placed against the clival defect (mean pedicle length 13.1 ± 0.6 cm). For ACBR defects, the RFFTT pedicle was examined in three orientations with respect to anterior–posterior axis of the RFFTT: anteriorly, posteriorly, and laterally. Lateral orientation offered the shortest average pedicle length required for anastomosis in the neck (11.6 ± 1.29 cm), followed by posterior (13.4 ± 0.7cm) and anterior orientations (14.4 ± 1.1cm) (p < 0.00001, analysis of variance).

Conclusions In ACBR reconstruction using RFFTT, our data suggests lateral pedicle orientation shortens the length required to safely anastomose facial vessels and protects the frontal sinus outflow anteriorly while limiting pedicle exposure through a maxillary corridor within the nasal cavity. With greater understanding of anatomical factors related to successful preoperative flap planning, free tissue transfer may be added to the ESBS reconstruction ladder.

Osteocutaneous radial forearm free flap for anterior cranial base reconstruction: Technical note

The reconstruction of anterior skull base defects after carcinologic surgery is challenging. Large defects can require the use of autologous free tissue transfer. Currently, most reconstructions use soft-tissue flaps. We describe the use of an osteocutaneous radial forearm free flap to reconstruct a large defect secondary to a malignant paraganglioma extending into the anterior cranial fossa and both orbits. The surgical resection required endonasal and transcranial approaches. We reconstructed the defect with a free osteocutaneous radial forearm flap. We laid the bone flap across the defect, resting on the orbital roof on each side, and sutured the soft component to the edge of the dura. The pedicle was funnelled from the craniotomy to a prepared cervicotomy and the micro-anastomoses were performed onto the facial artery and two satellite veins. Potential indications and major drawbacks of this technique are briefly discussed. Osteocutaneous radial forearm free flaps can be a valuable reconstructive option for patients with a large defect of the anterior skull base, needing both rigid support and a watertight closure.