Panorama of Reconstruction of Skull Base Defects: From Traditional Open to Endonasal Endoscopic Approaches, from Free Grafts to Microvascular Flaps

Abstract

Introduction A substantial body of literature has been devoted to the distinct characteristics and surgical options to repair the skull base. However, the skull base is an anatomically challenging location that requires a three-dimensional reconstruction approach. Furthermore, advances in endoscopic skull base surgery encompass a wide range of surgical pathology, from benign tumors to sinonasal cancer. This has resulted in the creation of wide defects that yield a new challenge in skull base reconstruction. Progress in technology and imaging has made this approach an internationally accepted method to repair these defects. Objectives Discuss historical developments and flaps available for skull base reconstruction. Data Synthesis Free grafts in skull base reconstruction are a viable option in small defects and low-flow leaks. Vascularized flaps pose a distinct advantage in large defects and high-flow leaks. When open techniques are used, free flap reconstruction techniques are often necessary to repair large entry wound defects. Conclusions Reconstruction of skull base defects requires a thorough knowledge of surgical anatomy, disease, and patient risk factors associated with high-flow cerebrospinal fluid leaks. Various reconstruction techniques are available, from free tissue grafting to vascularized flaps. Possible complications that can befall after these procedures need to be considered. Although endonasal techniques are being used with increasing frequency, open techniques are still necessary in selected cases.

Vascularized middle turbinate mucoperiosteal flap in skull base defects: follow-up analysis of 20 cases

“…In general, 2 and very good arc of rotation is the most effective of the vascularized flaps. It allows near perfect reconstruction of even extensive defects with a success rate as high as 95%.…”

“…2 However, NSF has its own share of limitations. It needs preemptive harvesting even before the skull base defect is assessed and prepared.…”

“…MTF has been advocated in many studies as a viable alternative for the reconstruction of defects involving crbriform plate, fovea ethmoidalis, planum sphenoidale, and sella in patients for whom NSF is not available. [2][3][4][5][6][7] In comparison to the NSF, size of MTF is small providing an effective surface area of only about 6 cm 2 which may not suffice in larger defects. 4,6 In many studies surface area as an independent factor did not correlate well with ability of the flap to cover sellar defects, while dimensions like length and width of the flap assumed more significance.…”

“…The recipient area should be adequately prepared beforehand and multilayer reconstruction after primary plugging with fat is always preferred. 2,11,13 The packing around the flap should not be too tight; Foley"s catheter should be inflated under endoscopic control within the nose, since hyperinflation can result in compromise of the vascular pedicle, displacement of the tissues or even intracranial compression.…”

“…Patients with sellar defects where NSF was unavailable or not practical were also chosen for closure with MTF. Exclusion criteria included patients who had larger skull base defects (> 3 cm 2 ) and sellar defects where NSF was available. Very small defects (< 0.5 cm 2 ) needing only free grafts for closure and patients with previous history of surgery on middle turbinate or sphenopalatine artery ligation were also excluded.…”