ABSTRACT
With the advent of microsurgery and surgical techniques, along with the improvement in neuroimaging techniques and the microanatomy in cadaver study, improvement in terms of surgical morbidity and mortality has been remarkable; however, controversy still exists regarding the optimal surgical strategies for giant petroclival meningiomas (GPMs). We report a study of clinical and radiological features as well as the surgical findings and outcomes for patients with GPM treated at our institution over the past 6 years. During a 6-year period (April 2004 to March 2010), 16 patients with GPM underwent surgery by subtemporal transtentorial petrosal apex approach during which electrophysiological monitoring of cranial nerves and brainstem function were reviewed. There were nine females and seven males with a mean age of 56.9 years (range from 32 to 78 years). The most frequent clinical manifestations were headache (93.7%) and dizziness (93.7%). Regions and directions of tumor extension include clivus, parasellar, and cavernous sinus, as well as compression of brainstem, and so on. The trochlear nerve was totally wrapped in nine cases (56.2%). The postoperative Karnofsky Performance Scale (KPS) score was 76.3 ± 13.1. Mean maximum diameter of the tumors on magnetic resonance imaging was 5.23 cm (range, 4.5 to 6.2 cm). Subtemporal transtentorial petrosalapex approach was performed in all 16 cases. Gross total resection was achieved in 14 cases (87.5%) and subtotal resection in 2 cases (12.5%) with no resultant mortality. Follow-up data were available for all 16 patients, with a mean follow-up period of 28.8 months (range from 4 to 69 months), of which 11 (68.75%) lived a normal life (KPS, 80-100). Our suggestion is that GPM could be completely resected by subtemporal transtentorial petrosalapex approach. The surgical strategy of GPM should be focused on survival and postoperative quality of life. Microneurosurgical technique plays a key role in tumor resection and preservation of nerve function. Intraoperative electrophysiological monitoring also contributes dramatically to the preservation of the nerve function. Complete resection of the tumor should be attempted at the first operation. Any remnant is treated by radiosurgery.
ABSTRACT
BACKGROUND: The subtemporal transtentoral approach has been reported for nearly two decades; however it was not well used due to some limitations in dealing with large and giant petroclival meningiomas. The clinical outcome and merit of the modified subtemporal transpetrosal apex approach in large and giant petroclival meningiomas, as well as the choices, the improvements and the therapy strategies of the microsurgical approach in such patients were evaluated in this study. METHODS: Totally 25 cases of large and giant petroclival meningiomas undergone the modified subtemporal transpetrosal apex approach between April 2004 and January 2010 were enrolled in this study. The choice and improvement of the approach, the basis of anatomy and related research, the effect of accessory equipment, the exposure of tumor and the changes of neurofunction pre- and post-operation were all reviewed retrospectively. The operation outcomes and complications in this approach were also compared with those in the transpetrous presigmoid approach done in 14 cases in the same period. RESULTS: All 25 cases underwent the modified subtemporal transpetrosal apex approach under electrophysiologic monitoring of cranial nerves and brain stem function. Trochlear nerve was partly wrapped in 14 cases, totally wrapped but can be explored in the initial segment of the cerebellum tentorium in 8 cases, totally wrapped and could not be seen until tumor was partly removed in 3 cases. The cerebellum tentorium was cut along the temporal bone from the anterior part of the apex to the mastoid part of superior petrous sinus in 6 cases, from the posterior part of the apex to the mastoid part of superior petrous sinus in 19 cases. Gross tumor resection was accomplished in 17 (68%) patients, subtotal resection in 7 (28%) patients, and partial resection in 1 (4%) patient. The most common postoperative complication was new neurological deficits or aggravations of preexisting deficit (64%). Follow-up ranged from 3 to 69 months. Compared with the transpetrous presigmoid approach done in 14 cases in the same period, the modified subtemporal transpetrosal apex approach showed obvious advantages such as simplicity in manipulating, microinvasiveness, less time-consuming, less complication, higher rate of tumor resection though the rates of gross tumor resection might be of no significant difference. CONCLUSIONS: Modified subtemporal transpetrosal apex approach has obvious advantages compared with the transpetrous presigmoid approach. Some complications need to be solved by practice and modification of the approach as well as the accumulation of the experiences.
