Lateral skull base surgery encompasses a number of lesions and also a variety of approaches to deal with them. Correct understanding of the nature of the lesion as also various patient factors are used to decide on surgical option wherever indicated. The extent of the lesion and also the involvement of structures adjacent to the lesion is discussed with the neuroradiology team, and is very important in deciding the most favorable surgical approach. The subject is explained preoperatively about staging of the procedure, if needed. The principle is to gain maximal exposure of the lesion with good control of the neurovascular structures along the surgical route, so as to minimize morbidity. Correct decision making and good skill help in achieving the best possible results.
Wolf J Mann
How to cite this article:
Zisiopoulou M, Gouveris H, Mann WJ. Management of Vestibular Schwannoma: Dependence on Stakeholder's View for Small and Medium-Sized Tumors. Int J Otorhinolaryngol Clin 2011; 3 (1):7-13.
Management options for patients with vestibular schwannoma include observation and active treatment, namely surgical resection, gamma knife stereotactic radiosurgery or fractionated radiation therapy. Although for large tumors microsurgery remains the mainstay of treatment, management of the small- and medium-sized vestibular schwannomas has been the matter of considerable controversy. Computerized clinical decision support systems have been developed to assist clinicians in this demanding task. Nonetheless, the complexity of the problem requires adaptation of the decision strategy to specific circumstances arising within a particular clinical scenario which can not always be modeled with adequate precision or addressed adequately within a mathematical framework. We present a set of clinical, neurophysiologic and radiologic parameters and the respective evidence which may guide carers’ decisions. These parameters include the size, growth rate and localization of the tumor, the age, general medical condition, facial nerve function, hearing and hearing deterioration rate, balance, vestibular and trigeminal nerve function of the affected individual, the estimated risk of malignant transformation and radiation-induced tumors, the health-related quality of life measures, the patient's and surgeon's preference and the issue of cost-effectiveness. A complex decision analysis, guided by evidence and tailored to each individual patient is required.
Jugular foramen tumors are rare cranial base lesions that present diagnostic and management difficulties. Paragangliomas were the most frequent lesions, followed by schwannomas and meningiomas. These tumors have characteristic radiological features. Radical resection of these tumors with preservation of the lower cranial nerves is the treatment of choice. Despite the advances in skull base surgery, new postoperative lower cranial nerve deficits still represent a challenge.
Paragangliomas or glomus tumors are usually low-grade hypervascular tumors occurring in various sites of the autonomic nervous system including the carotid body, glomus vagale and glomus tympanicum. Although the grading of the tumor suggests a benign clinical course, the tumor can be locally malignant and surgical management is sometimes difficult because of postoperative functional loss and local recurrence. In addition, the operative field is generally very bloody and tissue planes are not always well-defined.
Though the optimal management of paraganglioma occurs in a multidisciplinary setting, considering the excellent local control rates with primary irradiation alone, a nonsurgical definitive approach should initially be considered.
This paper reviews the diagnosis and treatment of temporal bone meningoencephaloceles, defined as the herniation of meninges or brain tissue into empty spaces within the temporal bone, i.e. tympanic or mastoid cavity, through the tegmen tympani or antri respectively. It also describes the current methods of control of cerebrospinal fluid (CSF) leaks, which commonly present as serous otorrhea or rhinorrhea in addition to a variety of symptoms, such as conductive hearing loss. Imaging is the mainstay of the diagnostic process. Management of the condition is surgical, and this review outlines the surgical options with special emphasis on the transmastoid approach and the materials applicable for repair of the bony dehiscences.
Deepak P Patkar,
Sona A Pungavkar,
Sudarshan Vijay Pawar
This article reviews the role of magnetic resonance imaging (MRI) in the evaluation of lateral skull base lesions. Due to superior soft tissue resolution and multiplanar capability, MRI provides accurate information and exquisite anatomical detail. Thus, it guides the surgeon in proper preoperative planning regarding the approach of a lesion. MRI is also useful in post-treatment follow-up to assess the therapeutic response and to identify potential complications. We discuss the relevant anatomy, indications of MRI and MR pulse sequences used in the diagnosis of lesions of lateral skull base. Characteristic MRI findings of various lesions which help to arrive at a specific diagnosis as well as pitfalls of MRI which may confound the diagnosis are described. Newer MR pulse sequences enable image-guided surgery, which assist the surgeon intraoperatively, are briefly discussed. In summary, this article emphasizes the role of MRI in providing a specific answer to a clinical problem and its ability to guide the clinician for better management of patients.
The current gamma knife radiosurgery technique involves the use of magnetic resonance imaging for targeting, the application of a low marginal dose (usually between 12 and 13 Gy) and highly conformal treatment planning using multiple small isocenters. This technique achieves an average tumor control rate of 95% and open surgery is needed in fewer than 2 to 3% of patients treated by gamma knife. Facial nerve function preservation is achieved in up to 99% of cases and chance of preserving serviceable hearing is usually between a 70 to 80%. The introduction of ventriculoperitoneal drainage after radiosurgery is required for 1 to 8% of patients. Gamma knife radiosurgery can be treatment of choice for the patients, where the diameter of the tumor is less than 3 cm.
In the radiosurgery era, the treatment strategies for vestibular schwannoma have changed at most centers. This new paradigm holds that rational CPA tumor therapy requires balancing often competing goals of therapy, and the associated risks and benefits of different therapies or combination of therapies. The present review discusses this new paradigm and its specific implications for CPA tumor surgery. Inevitably, such a review will focus largely on minimizing facial nerve morbidity, as this is both the most modifiable risk, and the risk that is most reduced with the use of adjuvant therapies, such as stereotactic radiosurgery (like Gamma knife). The facts about facial nerve preservation in CPA tumor surgery will be reviewed, and methods for avoiding facial nerve morbidity will be discussed.
How to cite this article:
Sankhla S, Morwani K, Jayashankar N. Should Gamma Knife be Offered as a Primary Treatment for a Resectable Glomus Jugulare Tumor?. Int J Otorhinolaryngol Clin 2011; 3 (1):71-74.
Attempted total resections is the preferred treatment option in the management of glomus jugulare tumors in most subjects. In the elderly patients, it may be advisable to leave a tiny residue over the involved cranial nerve to preserve function. In a medically unfit and anesthetically high-risk subject observation with serial MRI scans is the preferred line of management. If in such a patient there occurs brainstem compression, it is prudent to only operate the intracranial part to relieve the compression explaining the very high-risk in this group. Radiotherapy is not to be offered as a primary treatment for glomus jugulare tumors.