Background Petroclival meningiomas remain one of the most challenging skull base tumors. The
standard retrosigmoid approach is one of the most effective approaches, but this route
may have some limitations for the tumors extending into the supratentorial region
and middle cranial fossa. We review our clinical experience of retrosigmoid craniotomy
with tentoriotomy and suprameatal petrosectomy for this type of tumor removal.
Methods Between 2000 and 2016, a total of 46 patients underwent surgical treatment for petroclival
meningiomas. The mean age of the study group was 40.7 ± 11 years. Based on MRI, CT,
and angiography data, we preoperatively performed anatomical measurement, determined
angle of operating action, and wound depth. Depending on size and shape of tumor,
we used different types of retrosigmoid approach extensions (tentoriotomy and suprameatal
extension) for achieving angle of operating action more than 17° (reliable manipulation
zone).
Results Headache, balance disturbances, diplopia, facial pain, and numbness were the most
common clinical manifestation. Mean tumor size was 4.56 cm. As a result of anatomical
measurement, we described three surgical zones: a zone of “reliable manipulation”
with the angle of approach >17°, a zone of “risky manipulation” 15 to 17°, a zone
of “dangerous manipulation” <15° degrees. The main goal of our extensions of retrosigmoid
approach was creation of a new space for safe surgical manipulations in the zone of
“reliable manipulation.” Tentoriotomy was performed in 41 cases, and suprameatal extension
was used in 32 patients. Gross-total resection was achieved in 21 patients (45.7%).
Seven patients with residual tumor were treated with radiosurgery. Recurrence or tumor
progression was noted in five cases (10.9%). New postoperative cranial nerve (CN)
morbidity was observed in 18 cases (39.1%) and was presented III, IV, VI CN in 9 cases;
V CN in 8; VII CN in 3; and VIII CN in 2. In 10 patients, CN dysfunction was transient
and 8 patients had permanent dysfunction. At the time of discharge, 82% of patients
had Glasgow Outcome Scale Scores 4 and 5, and in 1 year 89% of patients were functionally
independent.
Conclusion Retrosigmoid craniotomy with tentoriotomy and suprameatal petrosectomy may be effective
alternative to the combined approaches for large petroclival tumors and provide good
functional result. Tendency for surgical radicality increases CN morbidity. Cranial
nerve's morbidity remains the main cause of disability in this group of patients.
