Surgical management of medium and large petroclival meningiomas: a single institution’s experience of 199 cases with long-term follow-up

Surgical management of medium and large petroclival meningiomas

Acta Neurochir (2016) 158:409–425

Petroclival meningiomas (PCMs) were once regarded as ‘inoperable’ due to their complex anatomy and limited surgical exposure. This study aimed to evaluate the long-term outcomes of surgically treated PCMs larger than 2 cm.

Methods A series of 199 consecutive patients (137 females, 68.8 %) with PCMs larger than 2 cm from between 1993 and 2003 were included. The clinical charts, radiographs, and follow-ups were evaluated.

Results Gross total resection (GTR) was achieved in 111 (55.8 %) patients, subtotal resection (STR) in 65, and partial resection (PR) in 23. Cranial nerve dysfunctions were the most common complications and occurred in 133 (66.8 %) cases. The surgical mortality was 2.0 %. The Karnofsky Performance Scale (KPS) scores significantly decreased 1 month after the operations (preoperative KPS=76.8 and postoperative KPS = 64.8; p = 0.011, Paired-samples t test). Long-term follow-ups were obtained in 142 patients, the follow-up duration was 171.6 months, and the most recent KPS was 83.2. Permanent morbidities remained in 24 patients (18.9 %). Multivariate analysis revealed that brainstem edema and tumors larger than 4 cm in diameter were independent risk factors in terms of outcomes (KPS < 80). The recurrence/ progression rates were 14.5, 31.8, and 53.3 % for the GTR, STR, and PR cases, respectively (p =0.002, Pearson χ2 test). Gamma Knife radiosurgery for the remnants exhibited good tumor control.

Conclusions Favorable outcomes and low mortality were achieved with the microsurgical management of medium and large PCMs; however, the rates of cranial nerves dysfunction remained high. Radically aggressive resection might not be judicious in terms of postoperative morbidity. The preoperative evaluations and intraoperative findings were informative regarding the outcomes. The low follow-up rate likely compromised our findings, and additional consecutive studies were required.

The Dorello canal: historical development, controversies in microsurgical anatomy, and clinical implications

Dorello's canal

Neurosurg Focus 34 (3):E4, 2013

Interest in studying the anatomy of the abducent nerve arose from early clinical experience with abducent palsy seen in middle ear infection. Primo Dorello, an Italian anatomist working in Rome in the early 1900s, studied the anatomy of the petroclival region to formulate his own explanation of this pathological entity. His work led to his being credited with the discovery of the canal that bears his name, although this structure had been described 50 years previously by Wenzel Leopold Gruber. Renewed interest in the anatomy of this region arose due to advances in surgical approaches to tumors of the petroclival region and the need to explain the abducent palsies seen in trauma, intracranial hypotension, and aneurysms. The advent of the surgical microscope has allowed more detailed anatomical studies, and numerous articles have been published in the last 2 decades. The current article highlights the historical development of the study of the Dorello canal. A review of the anatomical studies of this structure is provided, followed by a brief overview of clinical considerations.

Percutaneous biopsy of lesions in the cavernous sinus region through the foramen ovale: diagnostic accuracy and limits in 50 patients

J Neurosurg 116:390–398, 2012.DOI: 10.3171/2011.10.JNS11783

The cavernous sinus and surrounding regions—specifically the Meckel cave, posterior sector of the cavernous sinus itself, and the upper part of the petroclival region—are the location of a large variety of lesions that require individual consideration regarding treatment strategy. These regions may be reached for biopsy by a percutaneous needle inserted through the foramen ovale. The aim of this retrospective study was to evaluate the diagnostic accuracy of percutaneous biopsy in a consecutive series of 50 patients referred for surgery between 1991 and 2010.

Methods. Seven biopsies (14%) were unproductive and 43 (86%) were productive, among which 28 lesions subsequently underwent histopathological examination during a second (open) surgery. To evaluate the diagnostic accuracy of the procedure, results from surgery were compared with those from the biopsy.

Results. Sensitivity of the percutaneous biopsy was 0.83 (95% CI 0.52–0.98), specificity was 1 (95% CI 0.79–1), and k coefficient was 0.81.

Conclusions. Because of its valuable diagnostic accuracy, percutaneous biopsy of the cavernous sinus and surrounding regions should be performed in patients with parasellar masses when neuroimaging does not provide sufficient information of a histopathological nature. This procedure would enable patients to obtain the most appropriate therapy, such as resective surgery, corticosteroids, chemotherapy, radiotherapy, or radiosurgery.

Lateral supracerebellar transtentorial approach for petroclival meningiomas: operative technique and outcome

J Neurosurg 115:49–54, 2011. DOI: 10.3171/2011.2.JNS101759

The retrosigmoid intradural suprameatal approach with the patient in a semisitting position is an effective alternative to transpetrosal approaches for the treatment of petroclival meningiomas. The authors have made a simple modification to the retrosigmoid intradural suprameatal approach by using the lateral oblique position and preferentially dividing the tentorium with limited drilling of the suprameatal bone, which is termed the “lateral su- pracerebellar transtentorial approach.”

Methods. Twenty-six patients with petroclival meningiomas surgically treated via the lateral supracerebellar transtentorial approach were analyzed. All tumors had most of their bulk in the posterior fossa with some degree of extension into the middle fossa and/or Meckel cave. The patient is placed in the lateral oblique position, and a standard retrosigmoid craniotomy is performed. The tentorium medial to the trigeminal nerve is incised toward the free edge, which improves exposure to the petroclival region without extensive resection of the suprameatal petrous bone.

Results. Gross-total resection was achieved in 11 patients (42%). Ten patients (38%) underwent subtotal resection, and 5 patients (19%) underwent partial resection. There was no incidence of operative death, and the postoperative permanent morbidity rate was 15%. All patients except one did well postoperatively and were independent at the time of their last follow-up examinations.

Conclusions. The lateral supracerebellar transtentorial approach provides the simplest and safest access to the petroclival region. It offers an advantageous approach to petroclival meningiomas exclusively located in the posterior fossa with minimal extension into the Meckel cave and middle fossa.

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