Eleven patients who underwent surgery via the transzygomatic approach for the treatment of MCF tumors were enrolled in the present study. There were four males and seven females, and their ages ranged from 24 to 64 years (mean age, 50.5 years). The patients mainly presented with headaches (36.4%), dizziness (18.2%), hemiparesis (18.2%), and seizures (18.2%). The underlying pathologies included three cavernomas, three trigeminal schwannomas, three sphenoid wing meningiomas, one petroclival meningioma, and one hemangiopericytoma. Primary bone tumors and metastases were excluded. IOM, including MEP and EMG of the cranial nerves, was performed in all patients. The characteristics of the patients are summarized in .
Clinical Summary of 11 Patients Operated Via Transzygomatic Approach
Our surgical techniques included interfacial dissection of the temporalis muscle, osteotomy of the zygoma, low-positioned frontotemporal craniotomy, removal of the remaining squamous temporal bone, and extradural drilling of the sphenoid wing (), thus making a flat trajectory to the skull base. Two cuts were needed for the osteotomy of the zygoma. Titanium miniplates were applied to both lateral sides and removed before the osteotomies to facilitate the exact repositioning of the zygoma segments. The first cut was made through the root of the zygoma, just anterior to the temporomandibular joint. The second cut began at the frontozygomatic suture, which was parallel to the lateral orbital rim. The zygomatic arch was removed by freeing attachments from the masseter muscle. Opening of the cavernous sinus and V2,3 mobilization were performed for treatment of the cavernomas (case nos. 1, 2, and 3). Anterior petrosectomies were performed for the treatment of dumbbell-shaped trigeminal schwannomas (case nos. 4 and 5). Total, subtotal, and partial resections were achieved in nine, one, and one patient, respectively. The following surgical complications occurred: remote hemorrhage (case no. 3); wound infection (case no. 4); and prolonged operative time due to massive tumor bleeding (case no. 11).
Exposing the zygomatic arch after elevating the periosteum and superficial layer of the deep temporalis facia (A). Inferior reflection of the temporalis muscle after detaching the zygomatic arch (B).
MEPs and cranial nerve monitoring (third, fifth, sixth, and seventh nerves) were performed in 11 and 3 patients, respectively. Significant deterioration occurred during MEP recording in one patient (case no. 10). New weakness developed postoperatively which was permanent. In the patient with a hemangiopericytoma (case no. 11), MEP loss occurred with lowered blood pressure because of tumor bleeding, which recovered after an increase in blood pressure with successful hemostasis.
Long-lasting bursts and trains of neurotonic discharges did not develop during free-running EMGs of cranial nerves. New neurologic deficits developed postoperatively in four patients. Postoperative third nerve palsies developed in three patients (case nos. 2, 7, and 9). Ocular/trochlear motor nerve function remained unchanged in one patient (case no. 2) and improved in two patients (case nos. 7 and 9). Postoperative facial palsies and dysesthesias developed in one patient (case no. 5), which slowly recovered.