The combined subcranial-pterional approach to the anterolateral skull base

Endoscopic approaches to skull base malignancies affecting the anterior fossa

Anterior skull base malignancies are rare and comprise distinct histological entities. Surgery encompasses the traditional craniofacial resections (CFR), and more recently, endoscopic endonasal approaches (EEA) or a hybrid cranioendoscopic (CEA) technique. Although the CFR is still considered the "gold-standard;" there is growing evidence supporting that EEA yield equivalent oncologic outcomes with less morbidity in well-selected cases. Therefore, this article aims to review the current state-of-art in addressing anterior cranial base malignancies using expanded endoscopic endonasal approaches (EEA) with particular references to surgical anatomy and nuances of hybrid cranioendoscopic techniques. Cadaveric dissections and illustrative cases are presented to detail our current surgical technique allied with tailored adjuvant therapies, and treatment strategies are further discussed based on tumor histology.

Integrated PET/CT system for staging and surveillance of skull base tumors

BACKGROUND

The utility of preoperative and postoperative whole body integrated positron emission tomography-computed tomography (PET-CT) scanning for staging and follow-up in patients with skull base tumors is undetermined.

METHODS

We prospectively evaluated PET-CT findings in 47 patients using 57 scans. Most (35/47, 75%) had anterior skull base tumors and the majority (74%) had advanced-stage (III-IV) disease.

RESULTS

The scans showed high sensitivity for detection of various types of malignant tumors and provided 39 items of additional information, changing the clinical staging and management of 11 patients (23%). Recurrence of primary tumors was detected in 8 patients, positive regional (neck) metastases in 3, and distant metastases in 3. The positive uptake was due to osteoradionecrosis in 2 other patients. The sensitivity of PET-CT was 0.77 and the specificity was 0.81 (0.83 positive predictive value and 0.76 negative predictive value).

CONCLUSIONS

PET-CT provides accurate data on anatomy, tumor staging, and early disease recurrence in the skull base.

Skull base approaches in the pediatric population

BACKGROUND

This study aimed to examine the surgical, oncologic, and developmental results of infants and children undergoing extirpation of skull base tumors.

METHODS

Sixty-seven children aged 0.5 to 18 years (mean, 11 years) who were operated on during a 6-year period made up the study cohort. Eighteen cases (27%) involved malignant tumors, and 49 (73%) involved benign tumors. The most common benign tumors were craniopharyngioma (n = 10) and juvenile nasopharyngeal angiofibroma (n = 8). The most common malignant tumor was sarcoma (n = 5). Thirty-six tumors (55%) involved the anterior skull base, and the rest involved the lateral (n = 24) and posterior (n = 7) skull base. Subcranial, transfacial, and subfrontal approaches were used for extirpation of anterior skull base tumors. Voluminous or malignant tumors were excised by use of combined approaches (subcranial-transfacial, subcranial-degloving, or pterional-degloving). Twenty-two children underwent adjuvant therapy (chemotherapy, radiation, or both). Postoperative follow-up was 3 to 60 months.

RESULTS

No severe postoperative complications (ie, meningitis, cerebrospinal fluid leak, tension pneumocephalus) and no perioperative mortality occurred. Two and a half years later, 54 of the children (80%) are alive and well. Five children, two with optic glioma and one each with squamous cell carcinoma, ependymoma, and germinoma, have died of their disease. The subcranial approach had no cosmetic impact on the craniofacial development of the patients.

CONCLUSION

The extirpation of skull base tumors by use of conventional surgical techniques is feasible and safe among infants and children. The complication and mortality rates are lower than those in adults. The long-term cosmetic effect of the subcranial approach is negligible.

Skull base reconstruction after anterior subcranial tumor resection

Object

The goal of this study was to demonstrate the efficacy of a simple and reliable technique for anterior skull base and craniofacial reconstruction in patients who have undergone excision of tumors via the subcranial approach.

Methods

There were 63 patients who had undergone 71 anterior skull base resections of tumors via the aforementioned approach. Twenty-nine cases (41%) involved malignant tumors and 42 (59%) involved benign tumors. Reconstruction of the anterior skull base was performed by a single team who used double-layer fascial graft. Limited dural defects were reconstructed using the temporalis fascia, whereas large anterior skull base defects were reconstructed using a fascia lata sheath. Reconstruction was achieved without the support of bone graft or titanium mesh and without pericranial, galeal, or free flaps. Pericranial flap wrapping of the frontonasoorbital segment was performed to prevent osteoradionecrosis if postoperative radiotherapy was planned. The incidence of cerebrospinal fluid (CSF) leakage, intracranial infection, and tension pneumocephalus was 5.6%. Histopathological examination of fascia lata grafts obtained in patients who had undergone a second procedure demonstrated integration of vascularized fibrous tissue to the graft, as well as local proliferation of a newly formed vascular layer embedding the fascial sheath.

Conclusions

The use of a double-layer fascial graft alone was adequate for prevention of CSF leakage, meningitis, tension pneumocephalus, and brain herniation. The double-layer fascial flap provided a simple and reliable means for anterior skull base reconstruction after en bloc resection of both malignant and benign tumors.