Surgical nuances for nasoseptal flap reconstruction of cranial base defects with high-flow cerebrospinal fluid leaks after endoscopic skull base surgery

Abstract

<jats:p>Extended endoscopic endonasal approaches have allowed for a minimally invasive solution for removal of a variety of ventral skull base lesions, including intradural tumors. Depending on the location of the pathological entity, various types of surgical corridors are used, such as transcribriform, transplanum transtuberculum, transsellar, transclival, and transodontoid approaches. Often, a large skull base dural defect with a high-flow CSF leak is created after endoscopic skull base surgery. Successful reconstruction of the cranial base defect is paramount to separate the intracranial contents from the paranasal sinus contents and to prevent postoperative CSF leakage. The vascularized pedicled nasoseptal flap (PNSF) has become the workhorse for cranial base reconstruction after endoscopic skull base surgery, dramatically reducing the rate of postoperative CSF leakage since its implementation. In this report, the authors review the surgical technique and describe the operative nuances and lessons learned for successful multilayered PNSF reconstruction of cranial base defects with high-flow CSF leaks created after endoscopic skull base surgery. The authors specifically highlight important surgical pearls that are critical for successful PNSF reconstruction, including target-specific flap design and harvesting, pedicle preservation, preparation of bony defect and graft site to optimize flap adherence, multilayered closure technique, maximization of the reach of the flap, final flap positioning, and proper bolstering and buttressing of the PNSF to prevent flap dehiscence. Using this technique in 93 patients, the authors' overall postoperative CSF leak rate was 3.2%. An illustrative intraoperative video demonstrating the reconstruction technique is also presented.</jats:p>

MR Imaging Evolution of Endoscopic Cranial Defect Reconstructions Using Nasoseptal Flaps and Their Distinction from Neoplasm

“…A variety of biologic glues and temporary supportive nasal bolsters has been used to secure the ESBR layers to the cranial defect, while awaiting granulation and incorporation of the reconstructive tissues into the surgical bed. [8][9][10] The small dural defects have been successfully closed with nonvascularized free grafts such as seen in pituitary surgery. With the increasing size of cranial defects in EEA for resection of larger tumors and with deeper intra-arachnoid dissections and increased exposure to the cisterns, repair techniques using nonvascularized free grafts have shown unacceptable postoperative CSF leak rates.…”

“…11,12 A combination of intradural fat graft, inlay subdural collagen matrix, and/or the fascia lata with onlay NSF is effective in repairing cranial defects ( Fig 1C). [7][8][9][10] Most cranial defects are sufficiently closed by a single NSF elevated from one side of the nasal septum. Larger, extended cranial defects may require harvesting of bilateral nasoseptal flaps from both sides of the nasal septum and additional free mucosal grafts to cover the entire defect.…”

“…[1][2][3][4][5][6] Endoscopic skull base reconstruction (ESBR) with multilayer closure of the cranial base defect using vascularized tissues has become the repair method of choice in EEA, resulting in low CSF leak rates comparable with those in the open surgical approach. [7][8][9][10] The workhorse of ESBR in EEA is the vascularized pedicled nasoseptal flap (NSF), which is based on the nasoseptal branch of the sphenopalatine artery ( Fig 1A, -B). 11,12 A combination of intradural fat graft, inlay subdural collagen matrix, and/or the fascia lata with onlay NSF is effective in repairing cranial defects ( Fig 1C).…”

Endoscopic Endonasal Reconstructive Methods to the Anterior Skull Base

“…Several studies have described the reconstructive options following an expanded EEA to the skull base. 2,[5][6][7][8]20,21 In particular, in collaboration with our colleagues, Hadad et al, 22 we first introduced the vascularized pedicled NSF that has been the workhorse ever since and the primary reason for a substantial decrease in postoperative CSF leak and infection rates. 22 Based on our algorithm and experience, the NSF can be successfully placed over the majority of defects, regardless of the size and amount of CSF leak.…”

Surgical anatomy and utility of pedicled vascularized tissue flaps for multilayered repair of skull base defects

“…For this reason, pedicled flaps, such as the anteriorly based pericranial, temporoparietal fascial, temporalis muscle, and galeopericranial flaps, are frequently used to reconstruct the cranial base. 6,7,9,[15][16][17]19,23,24,26,31,32,37 More recently, endoscopic endonasal approaches have been popularized and a vascular pedicled flap of the nasal septum based on the nasoseptal artery (Hadad-Bassagasteguy flap or nasoseptal flap [NSF]) has also been introduced for skull base repair and is used extensively. 17,24 The aim of this report is to detail the surgical and anatomical properties of these versatile pedicled tissue flaps and to establish the technical nuances for multilayered skull base repair in clinical cases where these flaps may be used in combination.…”