Linear accelerator radiosurgery for treatment of vestibular schwannomas in neurofibromatosis 2.

Management of vestibular schwannomas in patients with neurofibromatosis 2 (NF2) balances growth control against preservation of hearing with the primary aim of maintaining patient quality of life. Surgical resection of these lesions carries greater risk of functional deterioration than in sporadic cases. Stereotactic radiosurgery is a less invasive option that provides comparable, if not superior outcomes to resection. Previous studies on the efficacy of stereotactic radiosurgery for vestibular schwannomas in NF2 have reported results from delivery by Gamma Knife systems. The efficacy of linear accelerator (LINAC) delivered treatment has not been specifically addressed. Modelling studies suggest that lesional conformality is superior with Gamma Knife, but clinical studies on sporadic vestibular schwannomas show equivalent results between the two systems. Our experience with LINAC radiosurgery in NF2 reported here shows good long-term growth control in four patients with vestibular schwannomas.

Update of radiosurgery at the Royal Adelaide Hospital.

This is an update of the Royal Adelaide Hospital radiosurgery experience between November 1993 and December 2004 comprising 165 patients with 168 intracranial lesions. Including re-treatment, there were 175 treatment episodes (163 radiosurgery and 12 stereotactic radiotherapy) at an average of 1.3 per month. The commonest lesions were acoustic neuroma (65), arteriovenous malformation (58), solitary brain metastasis (23) and meningioma (14). The clinical features, treatment details and outcome are described. Our results continue to be well within the range reported in the published work. Radiosurgery provides an elegant, non-invasive alternative to neurosurgery and conventional external beam radiotherapy for many benign and malignant brain tumours.

Radiosurgery for vestibular schwannomas: preliminary results of the Adelaide experience.

We present the preliminary results of our experience with Linear Accelerator (LINAC) radiosurgery for unilateral vestibular schwannomas. The treatment outcomes of 42 patients with a minimum follow-up of 12 months are reported. An excellent rate of tumour control was achieved with a relatively low complication rate. The current results compare favourably with other reported studies in the literature.

Radiosurgery at the Royal Adelaide Hospital: the first 4 1/2 years' clinical experience.

Radiosurgery refers to the treatment of small lesions localized by stereotactic technology using highly focused radiation. This review utilizes prospectively gathered data from the Royal Adelaide Hospital Radiosurgery unit to summarize experience with the first 62 patients (65 lesions) treated between November 1993 and May 1998. This experience included acoustic neuromas (23 patients), arteriovenous malformations (18), brain metastases (12), meningiomas (6), and glomus tumour, subependymoma, dural arteriovenous fistula (1 each). Although follow up is relatively short, the outcome in terms of morbidity and tumour control is thus far comparable with results reported in the literature. Radiosurgery provides a viable alternative to neurosurgery and conventional external beam radiotherapy for several benign and malignant intracranial lesions.

Acoustic neuroma--surgery or radiosurgery?

This paper discusses surgery and radiosurgery from the author's personal experience with both techniques. Multi-discipline assessment will allow the patient to make an informed decision regarding preferred management.

Arctic and Antarctic exploration including the contributions of physicians and effects of disease in the polar regions.

A history of Arctic and Antarctic exploration, whether to find a Northwest Passage, North Pole, or South Pole, is a story of triumph and tribulation. The hardship experienced by polar explorers in the last 1000 years permeates the tales of achievement. Physicians and surgeons have played prominent roles in all major polar explorations. No significant Arctic voyage, particularly in the last 300 years, was made without a member of the party trained in the management of medical emergencies and in basic surgery. During times of health, surgeons functioned as the voyage naturalists with expertise in biology, botany, zoology, and the writing of scientific catalogs. Spurred by our interest and fascination with the history of polar exploration, we reviewed the roles of physicians and natural scientists in Arctic and Antarctic adventures.

Spontaneous pneumocephalus.

Pneumocephalus (PC) is defined as an intracranial gas collection. The majority of cases of PC are secondary to trauma or are iatrogenic. Spontaneous, non-traumatic PC is an uncommon condition. Most cases of spontaneous PC occur in association with infection, neoplasia or disease of otogenic origin. The case of spontaneous PC being presented was felt to have resulted from air being forced into a small deficit in the posterior wall of the sphenoid sinus following an episode of nose blowing.

Extradural cavernous haemangioma simulating a disc protrusion.

Cavernous haemangiomas confined to the epidural space are rare and are therefore infrequently considered in the differential diagnosis of spinal epidural masses. In order to draw attention to this diagnosis, a case in which an epidural cavernous haemangioma simulates a lateral/foraminal disc protrusion is presented.

Surgical palliation of dyskinesiae in Parkinson's disease.

The history of surgical management of Parkinson's disease is outlined. Current practice of thalamotomy and pallidotomy is discussed. Surgical management has re-established its role in the management of Parkinson's disease.

Distal anterior cerebral artery aneurysms: a clinical series.

Thirty patients with distal anterior cerebral artery (DACA) aneurysms were seen at the Royal Adelaide Hospital in the period 1970-1996. There were seven males (23%) and twenty three females (77%) with a mean age of 50 years. The average follow up was 5 years. Multiple aneurysms were present in seven cases (23%). The mean size of aneurysms was 5 mm. There were two post-traumatic aneurysms and one mycotic aneurysm. Out of the 30 cases, 19 presented with subarachnoid haemorrhage from ruptured DACA aneurysms. Eight (42%) of them were in good clinical grade (I or II). Operations were carried out in 25 (83%) patients. All five cases with unruptured aneurysms and the eight patients with good clinical grade had good recovery. In contrast, only six (55%) out of 11 patients with poor clinical grade had good outcome. The overall management mortality for the 19 cases with ruptured aneurysms was 16%. Postoperative complication occurred in two cases (8%), one patient developed deep vein thrombosis and seizures, the other patient had transient upper limb weakness. Although there is a definite trend towards better management outcome in the published series of DACA aneurysms over the years, there is still significant mortality and morbidity in the poor grade patients. Early surgery will prevent the deaths from rebleeding and may allow optimal management of vasospasm.

Rendu-Osler-Weber syndrome: a current perspective on cerebral manifestations.

Rendu-Osler-Weber syndrome (hereditary haemorrhagic telangiectasia) is a vascular dysplasia characterized by recurrent epistaxis, mucocutaneous telangiectasia and a family history of the disorder. Although rare, it may cause significant morbidity to healthy and young individuals. We report three cases highlighting the cerebral manifestations of this disorder. These cases include cerebral abscess, cerebral haemorrhage and embolic stroke. These cerebral manifestations are due to complications associated with pulmonary arteriovenous fistulae or cerebral vascular malformations. The current management and screening for this disorder are reviewed.

An unusual spinal intradural arachnoid cyst.

Spinal intradural arachnoid cysts are seen most frequently in the thoracic region, particularly near the midline posteriorly. A thoracic intradural arachnoid cyst in this typical location is reported, with the additional unusual finding of herniation of the spinal cord through an anterior defect in the dura matter. The MRI findings are described.

Lymphocytic hypophysitis: a rare cause of hyperprolactinaemia.

Lymphocytic hypophysitis is one of the rare causes of hypopituitarism and intrasellar mass observed almost exclusively in women. A temporal relationship to pregnancy has been identified in many but not all of the 34 reported cases. Intra-operative differentiation from non-secretory macroadenoma is important, as resection of the anterior lobe is unnecessary in these individuals and pituitary function may spontaneously return to normal. The authors present the case of a woman with symptomatic hyperprolactinaemia 10 years after her last pregnancy.

Intracranial invasion from a primary adenocarcinoma arising in the middle and external ear.

Cerumenal adenocarcinoma is a rare neoplasm arising from the modified sweat glands of the ear. Before the diagnosis of primary tumour is made, a thorough search must be undertaken to exclude the possibility of metastatic disease, which occurs more commonly. Benign adenoma can also occur and this may be identical histologically to the malignant variety. The presence of local invasiveness may be the only differentiating feature. Aggressive local resection followed by postoperative radiotherapy form the cornerstone of management. Individuals treated with radiotherapy alone have a life expectancy of less than 12 months whereas cures have been reported with radical surgery.

Cavernous haemangiomas (angiomas) of the brain: clinically significant lesions.

A review of 2000 consecutive magnetic resonance imaging (MRI) brain studies identified 18 (0.9%) patients with lesions that satisfied MRI criteria for cavernous haemangiomas. The clinical, computed tomography (CT) and MRI findings in 23 patients with probable cavernous haemangiomas were compared. Thirty-three lesions were identified with multiple lesions in five (22%) patients. In 19 (82%) patients the neurological presentation corresponded to a cavernous haemangioma. The presenting symptoms were: seizures in 11 patients (48%); progressive neurological symptoms and signs in four (17%); and acute symptoms and signs due to haemorrhage in four (17%). T2 weighted images suggested the diagnosis in all cases, with 24 (73%) lesions showing the typical appearance of an area of mixed signal intensity with a rim of low signal intensity. In the absence of acute haemorrhage, CT demonstrated well circumscribed, round or oval hyperdense lesions without significant mass effect and with normal surrounding brain tissue in the majority of cases. Although not diagnostic, these CT features are strongly suggestive of cavernous haemangiomas.

Imaging of large Rathke's cleft cysts by CT and MRI: report of two cases.

Two patients with large Rathke's cleft cysts in the sella turcica and suprasellar region presented with visual impairment and hypopituitarism. The entirely different CT and MRI appearances of the two cysts were thought to depend principally on the protein content of the cyst fluid.

Intracerebral ganglioglioma.

A case of a rare intracerebral tumour, namely a ganglioglioma, is reported to illustrate the CT and MRI features. The finding of focal thinning of the inner skull vault in association with an adjacent intracerebral mass lesion can aid in the diagnosis of intracerebral ganglioglioma.

Lumbar disc prolapse on the contralateral side at the same level following discectomy.

Lumbar disc prolapse managed surgically is occasionally complicated by a recurrent ipsilateral prolapse of the residual disc material at the same level, but only rarely by prolapse on the contralateral side at that level. We present a case of the latter, successfully managed by a second microdiscectomy, and review the frequency of such cases in previous series.

Bony exostosis of the atlas with resultant cranial nerve palsy.

A case of tenth and twelfth nerve compression secondary to a bony exostosis of the first cervical vertebra is described. This uncommon phenomenon serves to outline the importance of imaging the course of a cranial nerve when no intracranial abnormality is demonstrable on CT or MRI. The radiologic features of spinal osteochondromas are reviewed.

CT and MR findings in patients with chordomas of the petrous apex.

Chordomas are rare neoplasms arising from remnants of the embryologic notochord. Although typically midline in site, intracranial tumors may arise off the midline, and a significant proportion of these arise unilaterally in the petrous bone. Three examples of this entity are presented, all demonstrating typical radiologic features. Dendritic branches of the cranial end of the notochord ramifying in the skull base are thought to provide the embryologic basis for this tumor. The CT and MR features demonstrated are similar to those of the more common midline chordomas. CT demonstrates a well-defined extraaxial soft-tissue mass associated with foci of calcification and bone destruction and occurring at a site corresponding with the embryologic distribution of notochordal material. On MR, prolonged T1 and T2 relaxation times result in hypointensity on T1-weighted images and marked hyperintensity on T2-weighted images. Signal voids result from the foci of calcification while hemorrhage may also lead to inhomogeneity.