Uğur Türe

Multimodality management of 26 skull-base chordomas with 4-year mean follow-up: experience at a single institution

SummaryObjective. To analyze a series of patients with pathologically confirmed skull-base chordoma, and to develop an algorithm for the management of this challenging disease based on the data, our experience, and the current literature.n Material and methods. Between the years 1986 and 2001, 26 chordoma patients received multimodality treatment with various combinations of conventional surgery, skull-base surgical techniques, and gamma-knife surgery at the Marmara University Faculty of Medicine. A total of 57 procedures (43 tumor excision surgeries, 7 gamma-knife procedures, and 7 other operations to treat complications) were performed. The mean follow-up period was 4 years (48.5 months). Karnofsky scoring was used to follow the patients’ clinical conditions, and magnetic resonance image analysis was used to measure tumor volume over time.n Results. Seven patients died during follow-up. Two of the deaths were due to surgical complications, four resulted from clinical deterioration related to tumor recurrence, and one was unrelated to neoplasia. The rate of tumor recurrence after the first surgical treatment was 58%. Residual tumor volume was lower in the cases in whom skull-base approaches were used as first-line management. The 19 survivors showed little change in clinical status from initial diagnosis to the most recent follow-up check. The mean follow-up time after gamma-knife treatment was 23.3 months. During this period, mean tumor volume increased 28% above the mean volume at the time of gamma-knife surgery. The mean Karnofsky score decreased by 6% during the same time frame.n Conclusions. The most effective first-line treatment for chordoma patients is surgery. The findings for residual tumor volume indicated that skull-base approaches are the best surgical option, and the complication rates for these techniques are acceptable. However, it is rare that surgery ever biologically eradicates this disease, and the data showed that these chordomas almost always progress if the tumor volume at the time of diagnosis exceeds 20u2009cm3. Based on our experience and the biological character of the disease, we now advocate radiosurgical treatment (gamma-knife in our case) immediately after the first-line skull-base surgery when the tumor residual volume is <30u2009cm3.

Anatomic Landmarks of the Glossopharyngeal Nerve: A Microsurgical Anatomic Study

OBJECTIVECompared with other lower cranial nerves, the glossopharyngeal nerve (GPhN) is well hidden within the jugular foramen, at the infratemporal fossa, and in the deep layers of the neck. This study aims to disclose the course of the GPhN and point out landmarks to aid in its exposure. METHODSThe GPhN was studied in 10 cadaveric heads (20 sides) injected with colored latex for microsurgical dissection. The specimens were dissected under the surgical microscope. RESULTSThe GPhN can be divided into three portions: cisternal, jugular foramen, and extracranial. The rootlets of the GPhN emerge from the postolivary sulcus and course ventral to the flocculus and choroid plexus of the lateral recess of the fourth ventricle. The nerve then enters the jugular foramen through the uppermost porus (pars nervosa) and is separated from the vagus and accessory nerves by a fibrous crest. The cochlear aqueduct opens to the roof of this porus. On four sides in the cadaver specimens (20%), the GPhN traversed a separate bony canal within the jugular foramen; no separate canal was found in the other cadavers. In all specimens, the Jacobson’s (tympanic) nerve emerged from the inferior ganglion of the GPhN, and the Arnold’s (auricular branch of the vagus) nerve also consisted of branches from the GPhN. The GPhN exits from the jugular foramen posteromedial to the styloid process and the styloid muscles. The last four cranial nerves and the internal jugular vein pass through a narrow space between the transverse process of the atlas (C1) and the styloid process. The styloid muscles are a pyramid shape, the tip of which is formed by the attachment of the styloid muscles to the styloid process. The GPhN crosses to the anterior side of the stylopharyngeus muscle at the junction of the stylopharyngeus, middle constrictor, and hyoglossal muscles, which are at the base of the pyramid. The middle constrictor muscle forms a wall between the GPhN and the hypoglossal nerve in this region. Then, the GPhN gives off a lingual branch and deepens to innervate the pharyngeal mucosa. CONCLUSIONTwo landmarks help to identify the GPhN in the subarachnoid space: the choroid plexus of the lateral recess of the fourth ventricle and the dural entrance porus of the jugular foramen. The opening of the cochlear aqueduct, the mastoid canaliculus, and the inferior tympanic canaliculus are three landmarks of the GPhN within the jugular foramen. Finally, the base of the styloid process, the base of the styloid pyramid, and the transverse process of the atlas serve as three landmarks of the GPhN at the extracranial region in the infratemporal fossa.

Experience of a single institution treating foramen magnum meningiomas

Despite the introduction of skull base approaches, there is still controversy in the optimum surgical management of foramen magnum meningiomas. Between January 1990 and January 2003, 22 patients underwent 23 surgical procedures with a diagnosis of foramen magnum meningioma at Marmara University, Department of Neurosurgery. The suboccipital approach was used for 2 posteriorly located tumors with radiological total removal. The paramedian suboccipital approach was replaced by the far-lateral modification in the treatment of ventral meningiomas. 1 of the 20 ventral tumors was operated twice. The classical suboccipital approach was followed by the far-lateral modification. A gross-total removal was achieved in 21 patients. The overall morbidity was 32%. No specific and clinically significant complications attributable to the far-lateral modification were observed. The far-lateral approach has improved the success of surgery in ventrally located lesions. The posterior suboccipital approach is still indicated in the removal of lesions placed posterior to the dentate ligament.

Surgical approach to thalamic tumors

AbstractIntroduction.Thalamic tumors comprise 1–5% of all brain tumors. Recent improvements in therapeutic approaches and surgical techniques have allowed a more accurate approach to these lesions and a reduction in morbidity and mortality.n Discussion.In this article, the various surgical approaches for the resection of thalamic tumors are described. Each of these approaches has its own indications and risk of complications.

Infratentorial lateral supracerebellar approach for trochlear nerve schwannoma

Schwannomas of the trochlear nerve are very rare. Only 25 cases without associated neurofibromatosis were reported in the literature, only 15 of which were surgically verified. We report an unusual case of a 31-year-old man who presented with isolated unilateral trochlear nerve palsy due to a left sided trochlear nerve schwannoma. The tumor was totally resected without additional morbidity using an infratentorial lateral supracerebellar approach.

Non-meningeal tumours of the cavernous sinus: A surgical analysis

The popularisation of cavernous sinus approaches and subsequent experience has shaped our treatment paradigms for cavernous sinus meningiomas. However, pathologies in this region are diverse and each one requires individual consideration. The purpose of this study was first to analyse, define and summarise the individual characteristics of different non-meningeal tumours of the cavernous sinus and, secondly, to stress that their surgery can be accomplished with acceptable morbidity and rewarding results when those characteristics are considered. A retrospective analysis of 42 cases of benign non-meningeal tumours of the cavernous sinus operated on at Marmara University between April 1992 and April 2003 is presented. The patients were 15 males and 27 females aged 24-72 years. The study cohort consisted of 13 pituitary adenomas, 11 trigeminal schwannomas, seven chordomas, three chondrosarcomas, two juvenile angiofibromas, two epidermoid tumours, one plasmacytoma, one cavernous haemangioma and one internal carotid plexus schwannoma. The 42 patients underwent 46 operations aimed at radical surgical excision. Total resection was achieved in 50% and subtotal resection in 50% of cases. The majority of incompletely resected tumours were pituitary adenomas and chordomas, and 95% required further treatment. Twenty-nine percent of patients developed complications, namely cerebrospinal fluid fistula, haematoma, hydrocephalus, diabetes insipidus, cerebral infarction and cranial nerve palsies. Recurrence was seen in 7.1% of patients. At final follow up at an average of 48.2 months after surgery, the mean Karnofsky performance scale had risen from 83.4 to 87.4. Non-meningeal tumours of the cavernous sinus can be surgically resected with acceptable morbidity and mortality. In selected tumours the results are better than those for cavernous sinus meningiomas. The best surgical results are achieved with interdural tumours of the lateral sinus wall and the worst surgical results are seen in invasive tumours such as chordomas and pituitary adenomas. Individual tumour characteristics are presented in the text.

Solid-calcified colloid cyst of the third ventricle

We report a 65-year-old female with a solid-calcified colloid cyst in the third ventricle that was demonstrated on computed tomography scan and magnetic resonance images. The lesion was surgically excised using the anterior transcallosal-transforaminal approach. Complete preservation of the surrounding neural and vascular structures was achieved.

Venous variations in the region of the third ventricle: the role of MR venography

In this study, we examined the anatomical variations of the subependymal veins in the region of the foramen of Monro and the third ventricle by MR time of flight (TOF) venography. Fifty healthy subjects, ten patients with third-ventricle tumors, and four patients with lateral-ventricle tumors were included in the study. The courses of the anterior septal vein (ASV), thalamostriate vein (TSV), and internal cerebral vein (ICV) were studied. The proximity of the venous angle, the false venous angle, and the ASV–ICV junction to the posterior margin of the foramen of Monro was measured. In 69 (53.9%) sides, the ASV–ICV junction was located at the venous angle and at the posterior margin of the foramen of Monro. In 59 (46.1%) sides, the ASV–ICV junction was located beyond the foramen of Monro. Our study shows the high incidence of posteriorly located ASV–ICV junctions, which can be crucial in the planning of a better surgical approach. We strongly recommend that MR venography, which is a short radiological examination, be used before one operates on third-ventricle and lateral-ventricle tumors.

MR imaging, CT, and angiography features of endolymphatic sac tumors: report of two cases

Abstract. Low-grade adenocarcinoma of endolymphatic sac origin is a rare tumor of the temporal bone. There are some difficulties in its differential diagnosis from other vascular and non-vascular tumors of the temporal bone. However its radiological differentiation from other tumors of the temporal bone is important for surgical planning. We present a report on two endolymphatic sac tumors with some specific radiological findings which can support a correct diagnosis.

Intradiploeic and cerebral hydatidosis : a case report and review of literature

A case of disseminated hydatidosis is reported in a 3-year-old male child who presented with intradiploeic, cerebral, pulmonary and hepatic hydatid cysts. The literature is reviewed for similar cases with skull involvement and the differential diagnosis of cystic skull lesions is discussed.