INTRODUCTION: Tumors arising from Meckel's cave, the cavernous sinus and the petroclival region can extend into both the posterior and middle fossa compartments. It may be challenging to achieve resection using single-session combined approaches, especially on the dominant side. We present a series of four cases of staged tumor resection using a retrosigmoid approach for the posterior fossa extension and an extradural temporo-polar approach for the middle fossa, cavernous sinus and Meckel's cave tumor components.
METHODS: We performed a retrospective review of patients who underwent staged resections for giant (>4cm) dumbbell-shaped tumors occupying both posterior and middle fossae between 2017-2022 operated on by a single surgeon. Information regarding demographics, symptomatology, imaging characteristics, surgical planning and resection and postoperative outcomes were collected.
RESULTS: Our search resulted in four cases are presented in Table 1. This series included three type C trigeminal schwannomas and one cavernous sinus meningioma (WHO Grade 2) with similar middle and posterior fossa extension. (Fig. 1) Symptoms are summarized in Table 1. Gross total resection was achieved in all three trigeminal schwannoma patients. Postoperatively, two patients had worsening of their facial numbness. (Table 2) There were no major complications and all patients are doing well at follow-up with no tumor recurrence or progression.
DISCUSSION: Some surgeons have advocated for a single session surgery for giant, multicompartmental dumbbell-shaped tumors. However, access into the posterior fossa and dissection of tumor off the brainstem is often limited. Selection of initial middle fossa versus posterior fossa tumor resection was dependent on patient symptomatology. (Table 2) Two patients presented seizures and significant facial numbness, therefore first underwent temporopolar resection of the symptomatic middle fossa component. The other two patients had symptoms from brainstem compression. For these patients, the posterior fossa component was resected first. Final resection of the cavernous and Meckel's cave components in one patient was achieved with a 30-degree endoscope.
CONCLUSIONS: The management of these complex and multi-compartmental skull base tumors continues to evolve and here we present our experience with staged resections for these lesions. The timing for middle vs posterior fossa approach is dependent on patient symptomatology. The addition of endoscopic assistance in one case allowed for resection of the tumor through an expanded Meckel's cave. The staged surgeries were safe, well-tolerated and effective techniques for the management of these tumors.
TABLES AND FIGURES
Table 1: Patient demographics, symptomatology and tumor characteristics
Table 2: Timing and approaches, post-operative complications and extent of resection (GTR: gross total resection, STR: subtotal resection
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Figure 1: (A) Type C trigeminal schwannoma, (B) Cavernous sinus meningioma (C) Type C trigeminal schwannoma