Quantitative determination of the optimal temporoparietal fascia flap necessary to repair skull‐base defects

Side-door temporoparietal fascia flap: First experience with a novel technique for anterior skull base reconstruction

BACKGROUND

Modern achievements in transnasal endoscopic skull base (SB) surgery have led to complex resections that render reconstruction a challenge. Temporoparietal fascia flap (TPFF) is a suitable option for SB reconstruction. The side-door TPFF technique for anterior SB reconstruction is described here for the first time in a real-life surgical setting.

METHODS

Patients affected by a SB malignancy who underwent cranioendoscopic resection were included. For reconstruction, a multilayer reconstruction technique including side-door TPFF transposition was employed.

RESULTS

TPFF transposition was performed in five patients. The TPFF could be easily transposed via a side-door approach. It adequately covered the edges of the defect and supported optimal healing of the surgical site. During follow-up, vitality and integration of the TPFF were assessed endoscopically and radiologically.

CONCLUSIONS

The TPFF side-door transposition technique is a valuable option in anterior SB reconstruction that can provide fast and effective healing, especially in patients needing adjuvant radiotherapy.

The Temporoparietal Fascia Flap Transposition Technique for Ventral Skull Base Reconstruction: Anatomic Analysis and Surgical Application

BACKGROUND AND OBJECTIVES

The temporoparietal fascia (TPF) flap is an alternative for revision endoscopic skull base reconstruction in the absence of the nasoseptal flap, and we aimed to investigate the anatomy and surgical application of TPF flap transposition in endoscopic endonasal surgery.

METHODS

Six lightly embalmed postmortem human heads and 30 computed tomography angiography imaging scans were used to analyze the anatomic features of the TPF flap transposition technique. Three cases selected from a 512 endoscopic endonasal cases database were presented for the clinical application of the TPF flap.

RESULTS

The TPF flap, composed by the deepest 3 scalp layers (galea aponeurotica, loose areolar connective tissue, and pericranium), can be harvested and then transposed through the infratemporal-maxillary-pterygoid tunnel to the ventral skull base. The superficial temporal artery as its feeding artery, gives frontal and parietal branches with similar diameter (1.5 ± 0.3 mm) at its bifurcation. The typical bifurcation was present in 50 sides (83.3%), with single (frontal) branch in 5 sides (8.3%), single (parietal) branch in 2 sides (3.3%), and multiple branches (>2) in 3 sides (5%). The transposed TPF flap was divided into 3 parts according to its anatomic location: (1) infratemporal part with an area of 19.5 ± 2.5 cm2, (2) maxillary part with an area of 23.7 ± 2.8 cm2, and (3) skull base part with an area of 44.2 ± 4 cm2. Compared with the nasoseptal flap, nasal floor flap, inferior turbinate flap, and extended septal flap, the coverage area of the skull base part of the TPF flap was significantly larger than any of them (P < .0001).

CONCLUSION

The TPF flap technique is an effective alternative for endoscopic endonasal skull base reconstruction. The TPF flap could successfully cover large skull base defects through the infratemporal-maxillary-pterygoid tunnel.

Transorbital transposition of the temporoparietal fascia flap to reconstruct the skull base defects: A preclinical study with comparison to the transpterygoid transposition

BACKGROUND

Transpterygoid transposition of the temporoparietal fascia flap (TPFF) is a feasible selection for ventral skull base defect (VSBD) reconstruction, but not anterior skull base defect (ASBD) reconstruction, after expanded endoscopic endonasal approach (EEEA). The goal of this study is to introduce the transorbital transposition of the TPFF for skull base defects reconstruction after EEEA, and make quantitative comparison between the transpterygoid transposition and transorbital transposition.

METHODS

Cadaveric dissections were performed in five adult cadaveric heads with creating three transporting corridors bilaterally, encompassing superior transorbital corridor, inferior transorbital corridor, and transpterygoid corridor. For each transporting corridor, the minimum necessary length of the TPFF for skull base defects reconstruction was measured.

RESULTS

The areas of ASBD and VSBD were 1019.63 ± 176.32 mm2 and 572.99 ± 126.21 mm2 . The length of the harvested TPFF was 149.38 ± 6.21 mm. In contrast to the transpterygoid transposition with incomplete coverage, transorbital transposition of the TPFF allowed full coverage of ASBD with a minimum necessary length of 109.75 ± 8.31 mm. For VSBD reconstruction, transorbital transposition of the TPFF needs shorter minimum necessary length (123.88 ± 4.49 mm) than transpterygoid transposition (138.00 ± 6.28 mm).

CONCLUSIONS

Transorbital corridor is a novel pathway for transporting the TPFF into the sinonasal cavity for skull base defects reconstruction after EEEA. In comparison with transpterygoid transposition, transorbital transposition provides wider coverage of skull base defects with a fixed length of the TPFF.

How I do it: epidural transposition of the temporoparietal fascia flap for anterior skull base reconstruction

BACKGROUND

Multilayer closures and the use of vascularized flaps have been showed to be very effective in the reconstruction of the anterior skull base (ASB) after extended endonasal approaches resulting in large bone and dural defects. In the case of unavailability of a local flap, regional ones like the temporoparietal fascia flap (TPFF), used until now via a transpterygoïd route (Bolzoni Villaret et al. in Eur Arch Otorhinolaryngol 270(4):1473-1479, 2023; Fortes et al. in Laryngoscope 117(6):970-976, 2017; Veyrat et al. in Acta Neurochir (Wien) 158(12):2291-2294, 2016), can be an effective alternative.

METHOD

We describe a step-by-step technique of TPFF transposition via an epidural supraorbital corridor for the reconstruction of a large midline ASB defect.

CONCLUSION

TPFF is a promising alternative for the reconstruction of the ASB defects.

Temporoparietal Fascia Flap Endonasal Transposition in Skull Base Reconstruction: Surgical Technique

Reconstruction of wide skull base defects resulting from multimodal treatment of cranial base malignancies are challenging.¹ Endonasal pedicled flaps (e.g., Hadad-Bassagusteguy flap)^1,2 are generally the first choice; however, inadequacy for the size and location of the defect or their unavailability are common occurrences in salvage reconstructions, and prior irradiation is an additional unfavorable condition for local flap viability. The temporoparietal fascia flap (TPFF)³ is a regional flap vascularized by the superficial temporal artery, which is able to survive and integrate even in postirradiated areas. Its properties, such as thinness, pliability, foldability, and the long pedicle, make it a versatile flap for reconstruction of various defects of the skull base, both in adults^3-7 and children.⁸ In lateral skull surgery, TPFF proved to be effective in patients at higher risk of cerebrospinal fluid leak,⁷ whereas its transposition into the nasal cavity through a temporal-infratemporal tunnel has been widely reported to repair defects of the ventral skull base.^3-6 It represents a safe and effective technique with minimal additional morbidity (potential alopecia or scalp necrosis).^4,5 A recently described modification of this technique supports TPFF transposition via a supraorbital epidural corridor to reach the anterior skull base, especially for large defects with supraorbital extension.⁶ The present video (Video 1) shows the step-by-step TPFF harvesting and endonasal transposition via a temporal-infratemporal tunnel to repair a wide middle cranial fossa defect resulting from osteoradionecrosis after endoscopic resection and heavy-particle radiation therapy for sinonasal adenoid-cystic carcinoma. At 6-months follow-up, optimal healing without complications was observed.