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Venelin M. Gerganov, Nirjhar Hore, Christian Herold, Karsten Wrede, Alexandru C. Stan, Amir Samii and Madjid Samii

✓Although intracranial metastases of malignant melanomas are common, localization at the cerebellopontine angle (CPA) or in the internal auditory canal (IAC) is rare, and bilateral presentation especially so. We present the case of a 46-year-old Caucasian woman with bilateral IAC/CPA lesions and a prior history of malignant melanoma on the right leg. During preoperative investigations, the presence of the bilateral IAC/CPA lesions along with several radiologically identified lesions along the neural axis led to the suspicion that she had neurofibromatosis Type 2 despite her history of malignant melanoma and the lack of characteristic skin lesions and family history. Histopathological analysis of the resected lesion confirmed the intraoperative diagnosis of bilateral CPA malignant melanoma metastases. Surgical removal of the tumors via the retrosigmoid approach with preservation of normal bilateral facial nerve function and unilateral serviceable hearing, combined with control of the systemic disease, provided this patient with a near-normal quality of life for at least 42 months after the initial diagnosis of melanoma.

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Amir Samii, Venelin M. Gerganov, Christian Herold, Nakamasa Hayashi, Takahiko Naka, M. Javad Mirzayan, Helmut Ostertag and Madjid Samii

Object

The goal of this study was to report on the surgical management of skull base chordomas and to evaluate both the short- and long-term treatment outcomes.

Methods

The authors retrospectively studied data from 49 patients who had undergone consecutive surgeries at a single institution. They also analyzed patterns of chordoma extension. Complications and surgery-related morbidity were recorded. A Kaplan–Meier analysis was performed to determine survival rates in patients 5 and 10 years after their first surgery. Operative approaches were selected on the basis of the predominant tumor extension.

Results

The approach used most frequently was the transethmoidal in 36.3%, followed by the pterional in 23.4% and the retrosigmoid in 23.4%. The tumor was totally removed in 49.4% and subtotally in 50.6%. The rate of total removal was highest at initial surgery (78%) and progressively declined thereafter. In 11.8% of cases a new neurological deficit developed, while the preoperative deficit remained unchanged. In 20% of cases the preoperative deficits improved, but new deficits also appeared. The 5- and 10-year survival rates are 65 and 39%, respectively.

Conclusions

With an individually tailored surgical approach, total tumor removal in 78% of the cases was achieved at the initial surgery. Radical surgery appears to increase slightly the surgical morbidity, but at the same time prolongs the recurrence-free interval. Chordomas cannot be regarded as surgically curable tumors given the 5- and 10-year survival rates in patients harboring such lesions.

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Mario Giordano, Karsten H. Wrede, Lennart H. Stieglitz, Madjid Samii and Wolf O. Lüdemann

Object

The purpose of this study was to determine the ability of software-assisted 3D reconstruction performed using a neuronavigation system to delineate the anatomy and variation patterns of the pineal region venous complex, and then to compare these data with previous anatomical findings.

Methods

The authors retrospectively reviewed the neuroimages obtained in 100 patients with intracranial lesions (50 computed tomography [CT] scans obtained with contrast agents and 50 magnetic resonance [MR] images obtained with gadolinium) by using a neuronavigation workstation for 3D reconstruction. Particular attention was given to the internal cerebral vein, basal vein (BV), and the vein of Galen. The various connection patterns between the major vessels were classified and statistically analyzed.

Conclusions

The venous system of the pineal region shows a wide range of sex-related variations. In the female patient the absence of a BV (Type 0) is significantly more frequent than in the male. In this study the authors illustrate the ability to depict the venous drainage patterns in the pineal region for all cases studied by using 3D neuronavigation software without the need for additional examinations. This simple tool provides important information for surgical planning and may be of significant help intraoperatively.

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Jeremy C. Ganz

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Domenico Solari, Francesco Magro, Paolo Cappabianca, Luigi M. Cavallo, Amir Samii, Felice Esposito, Vincenzo Paternò, Enrico de Divitiis and Madjid Samii

Object

The pterygopalatine fossa is an area that lies deep within the skull base. The recent extensive use of the endoscopic endonasal approach has provided neurosurgeons with a method to reach various areas of the skull base through a less invasive approach than traditional transcranial or transfacial approaches. This study aims to provide neurosurgeons with new data concerning direct endoscopic measurements and precise anatomical topography features of the pterygopalatine fossa.

Methods

An anatomical dissection of six fixed cadaver heads (12 pterygopalatine fossae) was performed to analyze spatial relationships and distances between the most important neurovascular structures in this region, and to estimate the size of the endoscopic surgical field for operations in this area. The endoscopic endonasal approach offers direct access to the pterygopalatine fossa through its anteromedial walls.

Conclusions

Using an endoscopic endonasal approach makes it possible to identify all of the anatomical landmarks of the pterygopalatine fossa and almost all of the contiguous skull base areas.

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Madjid Samii, Andrei Koerbel, Sam Safavi-Abbasi, Federico Di Rocco, Amir Samii and Alireza Gharabaghi

✓ Increasing rates of facial and cochlear nerve preservation after vestibular schwannoma surgery have been achieved in the last 30 years. However, the management of a partially or completely damaged facial nerve remains an important issue. In such a case, several immediate or delayed repair techniques have been used.

On the basis of recent studies of successful end-to-side neurorrhaphy, the authors applied this technique in a patient with an anatomically preserved but partially injured facial nerve during vestibular schwannoma surgery. The authors interposed a sural nerve graft to reinforce the facial nerve whose partial anatomical continuity had been preserved. On follow-up examinations 18 months after surgery, satisfactory cosmetic results for facial nerve function were observed.

The end-to-side interposed nerve graft appears to be a reasonable alternative in cases of partial facial nerve injury, and might be a future therapeutic option for other cranial nerve injuries.

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Madjid Samii, Makoto Nakamura, Shahram Mirzai, Peter Vorkapic and Andres Cervio

Object

The aim of this study was to describe the symptomatology, radiological features, and surgical treatment of patients with cavernous angiomas within the internal auditory canal (IAC).

Methods

The authors reviewed the cases of seven patients with cavernous angiomas in the IAC that had been surgically treated in the 22-year period between 1983 and 2005. All the patients had presented with sensorineural hearing loss, and four suffered from tinnitus. Four patients also reported facial symptoms such as hemispasm or progressive palsy; one of these patients had presented with sudden facial paresis due to intrameatal tumor hemorrhage. According to computed tomography (CT) results, the lesions caused enlargement of the IAC. Interestingly, these same angiomas showed variable features on magnetic resonance (MR) imaging, making their differentiation from intrameatal vestibular schwannomas (VSs) sometimes impossible. In all patients the lesions were totally removed via the suboccipital retrosigmoid approach. They could be dissected away from the facial nerve in five cases, whereas in two cases, because of the location of the lesion, the seventh cranial nerve had to be sectioned and repaired with a sural nerve graft. Transient worsening of seventh cranial nerve symptoms occurred in two patients, with postoperative improvement in each of them. The cochlear nerve could not be functionally preserved because of its extreme adherence to the tumor, although its continuity was preserved in four patients. Complete deafness was the only postoperative complication.

Conclusions

Cavernous angiomas of the IAC are very uncommon lesions that can imitate the symptoms of VSs. Although it is the most sensitive study available, MR imaging does not show sufficiently specific findings to differentiate the two lesion types. Thus, the preoperative diagnosis must be based on patient symptoms plus the CT and MR imaging features.

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Madjid Samii, Venelin Gerganov and Amir Samii

Object

The aim of this study was to evaluate and present the results of current surgical treatment of vestibular schwannomas (VSs) and to report the refinements in the operative technique.

Methods

The authors performed a retrospective study of 200 consecutive patients who had undergone VS surgery over a 3-year period. Patient records, operative reports, follow-up data, and neuroradiological findings were analyzed. The main outcome measures were magnetic resonance imaging, neurological status, patient complaints, and surgical complications.

Complete tumor removal was achieved in 98% of patients. Anatomical preservation of the facial nerve was possible in 98.5% of patients. In patients treated for tumors with extension Classes T1, T2, and T3, the rate of facial nerve preservation was 100%. By the last follow-up examination, excellent or good facial nerve function had been achieved in 81% of the cases. By at least 1 year postsurgery, no patients had total facial palsy. In the patients with preserved hearing, the rate of anatomical preservation of the cochlear nerve was 84%. The overall rate of functional hearing preservation was 51%. There was no surgery-related permanent morbidity in this series of patients. Cerebrospinal fluid leakage was diagnosed in 2% of the patients. The mortality rate was 0%.

Conclusions

The goal of VS treatment should be total removal in one stage and preservation of neurological function, as they determine a patient’s quality of life. This goal can be safely and successfully achieved using the retrosigmoid approach.

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Alireza Gharabaghi, Andrei Koerbel, Amir Samii, Jan Kaminsky, Henning Von Goesseln, Marcos Tatagiba and Madjid Samii

Object

Surgical manipulation of the fifth cranial nerve during its intra- or extracranial course may lead to bradycardia or even asystole as well as arterial hypotension, a phenomenon described as the trigeminocardiac reflex (TCR). The authors studied the impact of this reflex on postoperative auditory function in patients undergoing vestibular schwannoma (VS) surgery.

Methods

One hundred patients scheduled for VS surgery were studied prospectively for parameters influencing the postoperative auditory function. The evaluation included sex, age, pre- and postoperative auditory function, preoperative mean arterial blood pressure, preoperative medical diseases or medication (for example, antiarrhythmia drugs), tumor size and localization, and the intraoperative occurrence of the TCR.

The TCR, which occurred in 11% of the patients, influenced the postoperative hearing function in the patients with Hannover Class T3 and T4 VSs.

With an overall hearing preservation of 47%, 11.1% of the patients in the TCR group and 51.4% of those in the non-TCR group experienced preserved hearing function postoperatively. In cases involving larger tumors (Hannover Class T3 and T4), an intraoperative TCR was associated with a significantly worse postoperative hearing function during VS surgery (p = 0.005).

Conclusions

The hypotension following TCR is a negative prognostic factor for hearing preservation in patients undergoing VS surgery. Patients’ knowledge of this can be increased pre- and postoperatively. Further study of this phenomenon will advance the understanding of the underlying mechanisms and may help to improve hearing preservation by controlling the occurrence of the TCR.

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Andrei Koerbel, Alireza Gharabaghi, Sam Safavi-Abbasi, Marcos Tatagiba and Madjid Samii

The extraordinary improvement of patient outcome after surgical treatment for vestibular schwannomas is relatively recent and has occurred mainly over the last 30 years. The introduction of microsurgical techniques has resulted in increasing degrees of precise anatomical and functional preservation of the facial and cochlear nerves. An expanded microsurgical technique accompanied by continuous electrophysiological monitoring has resulted in marked changes in the primary goals for this surgery. Whereas in the past the primary goal of vestibular schwannoma management was to preserve the patient's life, the objective in vestibular schwannoma treatment today is to preserve neurological function.

Long-term follow-up examinations show negligible recurrence rates, indicating that the aim of preservation of nerve function does not limit the completeness of tumor removal with modern neurosurgical techniques. Despite these advances in preserving the anatomical integrity of, for example, the cochlear nerve, losses of function and even deafness may occur postoperatively in some cases. Current biological and technical research in experimental and clinical settings addresses these problems. In this article, the authors report in detail the developments achieved in vestibular schwannoma surgery and the great clinicians to whom these results can be credited.