Reconstruction after extended endonasal approaches to the anterior cranial base: surgical techniques and current results

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Approach to the Anterior Cranial Fossa

Introduction  The development of endoscopic techniques has made endoscopic endonasal approaches (EEAs) to the anterior cranial fossa (ACF) increasingly popular. Still, the steps and nuances involved in the approach may be difficult to understand for trainees. Thus, we aim to didactically describe the EEAs to the ACF in an anatomically based, step-by-step manner with supplementary clinical cases. Methods  Six cadaveric head specimens were dissected. Endoscopic endonasal Draf I, IIA, IIB, and III frontal sinusotomies, endoscopic endonasal superior ethmoidectomy, and endoscopic endonasal transcribriform and transplanum approaches were modularly performed. The specimens were photodocumented with endoscopic techniques. Results  Draf I frontal sinusotomy started with the complete removal of the anteromedial portion of the agger nasi cell, exposing the medial orbital wall, cranial base, and anterior cribriform plate. Draf II frontal sinusotomy proceeded with the removal of the floor of the frontal sinus between the lamina papyracea and the middle turbinate (IIa), and the nasal septum (IIb) until the first olfactory filaments were exposed. Draf III proceeded by creating a superior septal window just below the floor of the frontal sinus. The bone of the ACF bounded by the limbus sphenoidale posteriorly, frontal sinus anteriorly, and the medial orbital walls bilaterally was removed; the cribriform plate was removed; and the crista galli was dissected free from the dural leaflets of the falx cerebri and removed. Conclusion  We provide a step-by-step dissection describing basic surgical steps and anatomy of the EEAs to the ACF to facilitate the learning process for skull base surgery trainees.

Endoscopic Reconstruction of the Sellar Floor by Extended Inferior Turbinate Flap in Recurrent Pituitary Tumors

Objective  This aim of this study was to address the outcome of endoscopic reconstruction of the sellar floor by extended inferior turbinate flap. Patients and Methods  This is a retrospective study of 34 patients with a recurrent pituitary tumor. They were treated between March 2018 and December 2021 by endoscopic extended endonasal approach with the reconstruction of the sellar floor by an extended posterior pedicle inferior turbinate flap. The clinical and radiological follow-up was performed immediately postoperation and regularly every 3 months up to 1 year, and the available data from the last follow-up visit were included in the analysis. Results  The patients' age ranged between 40 and 65 years, with a slight female predominance (55.9%). Headache was the main presentation (47.1%), and functional tumors were found in 50.0% patients. Visual disturbances were field defects among 61.8% and papilledema among 52.9% patients. Preoperative endoscopy revealed postseptectomy as the significant finding (73.5%), followed by postseptectomy and adhesion (14.7%) and finally postseptectomy and hypertrophied inferior turbinate (11.8%). Total tumor resection was achieved in 76.5%, visual improvement was recorded in 52.9%, and no complications were reported in 82.4% patients. Cerebrospinal fluid (CSF) leak was not reported in any of the studied patients. Finally, total resection was significantly associated with younger age, non-functioning tumor and improvement of headache. Conclusion  The extended inferior turbinate flap is an effective and safe approach for sellar floor reconstruction in endoscopic endonasal surgery for recurrent pituitary tumors. The extension overcomes the relatively small inferior flap and its limited arc of rotation.

Fascia Lata: Another Workhorse for Complex Skull Base Reconstruction

BACKGROUND

Multiple methods exist for skull base reconstruction of defects created by expanded endonasal approaches. While the nasoseptal flap (NSF) has been well established as the workhorse of mucosal reconstruction in complex skull base defects in multi-layered closures, a variety of options exist for the inner layer of multilayer reconstruction, including fascia lata (FL).

OBJECTIVE

To present our experience and outcomes in utilizing FL in multiple ways to reconstruct a wide variety of complex skull base defects.

METHODS

Retrospective review was performed from May 2017 to February 2022 to identify 50 consecutive patients who underwent endoscopic skull base reconstruction using FL.

RESULTS

FL was employed for reconstruction in 50 patients included in the study: 37 undergoing primary expanded endonasal skull base surgery and 13 revision cases. A wide range of complex pathology was treated, with meningioma and craniopharyngioma being the two most common. FL was utilized as a "button" graft (34/50, 68.0%), free graft inlay/onlay (13/50, 26.0%), and as a button graft combined with onlay (3/50, 6.0%). Expanded surgery defects addressed included tuberculum sella/sphenoid planum (36/50, 72.0%), clivus (6/50, 12.0%), and cribriform/planum (8/50, 16.0%). Successful reconstruction with fascia lata was accomplished in 46/50 cases (92%), with only 4 cases (8%) requiring revision for post-op CSF leak. Donor-site complications were rare with only 1 case (2.0%) of post-op seroma.

CONCLUSION

FL, usually with NSF, offers a versatile option for the reconstruction of challenging defects with excellent outcomes and minimal morbidity. FL is emerging as a workhorse for reconstruction of the inner layer of complex skull base defects.

Application of dural suturing in the endoscopic endonasal approach to the sellar region

Objectives

The endoscopic endonasal approach (EEA) is widely used in the treatment of cranial base tumors. Skull base reconstruction is a crucial part of EEA, which has a great impact on patients’ prognosis. In this study, we report our experience with sellar dural suturing in cranial base reconstruction and retrospectively analyze its effect.

Methods

The clinical data of 134 patients who suffered intraoperative CSF leakage and underwent EEA surgery in the Department of Neurosurgery of the First Affiliated Hospital of Nanjing Medical University from October 2018 to November 2020 were retrospectively collected and analyzed. According to whether sellar dural suturing was performed during the operation, they were divided into a suture group (55 cases) and a control group (79 cases).

Results

The results showed that dural suturing of the sellar floor effectively reduced the postoperative hospitalization duration (p = 0.026) and the use rates of lumbar drainage (p = 0.047), autologous fat transplantation (p = 0.038), and pedicled nasoseptal flaps (p = 0.026).

Conclusion

Sellar dural suturing under endoscopy is a promising and effective method for cranial base reconstruction in EEA surgery and is worthy of clinical application.

Endoscopic Endonasal Repair of Recurrent Cerebrospinal Fluid Leak With Adipofascial Anterolateral Thigh Free Flap: Case Report and Review of Literature

Background. Cerebrospinal fluid leaks are the most common complication of endoscopic endonasal skull base tumor resection. The workhorse nasoseptal flap or other vascularized intranasal flaps may not be a viable option in patients who have previously undergone surgery or local radiation; in these cases, pericranial flaps may also be unavailable. Free flap reconstruction in patients undergoing endoscopic resection is challenging because of limited exposure. The transmaxillary approach has recently been reported for free flap reconstruction of these defects. This report describes a patient with a pituitary tumor who underwent craniotomy and resection of a pituitary mass via an endoscopic endonasal approach. Postoperatively, the patient developed a high flow cerebrospinal fluid leak that did not resolve with lumbar drain and attempts at endoscopic revision of nasoseptal flap. An adipofascial anterolateral thigh free flap was harvested, based on the descending branch of the lateral circumflex femoral vessels. An upper gingivobuccal sulcus incision was used to access the maxilla. Openings were created in the anterior and medial maxillary sinus to create a passage to the sphenoid sinus. The flap was inset into the defect via this transmaxillary channel. The pedicle was tunneled subcutaneously through the cheek to recipient facial vessels. The procedure resulted in complete resolution of cerebrospinal fluid rhinorrhea and pneumocephalus. Imaging at 18 months showed the flap in good position. This report describes the technique in detail along with a review of the current literature.