PARAPETROSAL PRESIGMOID APPROACH FOR PETROCLIVAL TUMORS

Objective To discuss the operative technique of parapetrosal presigmoid approach for patients with petroclival tumors and its outcome. Methods 16 petroclival tumors have been microsurgical treated with parapetrosal presigmoid approach and the clinical data were analysed retrospectively. Results In all patients, 9 had meningiomas, 3 epidermoid cysts, 2 pontine gliomas, and 2 schwannomas. Total resection was performed in 12 patients, subtotal resection in 3, and near subtotal resection in 1. Temporary post-operative cranial nerve paresis occurred in 3 patients but no CSF leakage and mortality ever occurred. Conclusion This approach is simpler and safer than other more extensive transpetrosal approaches. It can expose sufficiently the petroclival regions and facilitate tumor removal and provides good clinical outcome.

Subtemporal transpetrosal apex approach： study on its use in large and giant petroclival meningiomas

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.

Keyhole approach surgery for petroclival meningioma

Background In China, the feasibility of keyhole approach in surgical treatment of petroclival meningioma has not been well evaluated. This report summarized our experience in 25 patients with petroclival meningioma who had been treated with keyhole approach surgery. Methods From July 2000 to July 2005, 25 patients with petroclival meningioma were subjected to resection via subtemporal, retrosigmoid or combined keyhole approaches. The extent of tumor resection was evaluated by MRI 3 months after surgery, and postoperative complications were investigated. Results The maximum diameter of tumors ranged from 2 to 7 cm （mean, 4.5 cm）. Gross total resection （GTR） was achieved in 14 patients, giving a GTR rate of 56%. Subtotal resection （STR） was carried out in 8 patients and partial resection in 3. Thirteen patients kept normal neurological status, whereas others suffered from cranial nerve deficits （Ⅶ, Ⅶ, Ⅲ and lower CN）. One patient died in the postoperative period. Conclusions Keyhole approach surgery, especially the combined keyhole approach is suitable for the treatment of petroclival meningioma. It provides easy and quick access to the supra- and infratentorial juxta-clival region without drilling of the petrous bone. Complications related to the approach can be minimized.

Retrosigmoid-transtentorial approach for petroclival meningiomas: operative technique and clinical outcome

Background:Petroclival meningiomas (PCMs) are technically challenging lesions.Although the standard retrosigmoid approach is one of the most effective approaches,this route may have some limitations for the tumors extending into the supratentorial region and middle cranial fossa.We provide a modified surgical technique called retrosigmoid-transtentorial approach (RTTA) to solve these problems.The feasibility and efficacy of the RTTA were studied,by analyzing neurological outcomes and considerations of surgical strategies.Methods:We analyzed 64 of 71 PCM patients (90.1％).All 64 patients had epicenter of tumor in the posterior fossa with varying degrees of extension into the supratentorial area and/or the middle fossa.A conventional retrosigmoid craniotomy was performed following which the tentorium was incised from the attachment of tumor toward the free edge,which improved exposure to the petroclival region by offering additional operative room without resection of the adjacent part of the petrous bone.Results:The rate of gross total resection was 71.9 ％.There was no incidence of intraoperative death.One patient died in the postoperative phase.The postoperative permanent morbidity rate was 25.4 ％.Follow-up was done with the mean time of 60.7 ± 47.5 months.There were 6 recurrence,8 progression and 7 death cases and the mean KPS score was 83.2 ± 13.4 in the last follow up.Conclusions:The RTTA achieves the goal of applying a safe,quick,uncomplicated,and lesser invasive access to the petroclival region which is indicated for tumors located in the posterior fossa with some extension into the supratentorial area and/or the middle fossa.