Practical neurology - 3: Back pain and leg weakness.

Back pain is very common; it has a point prevalence of 25% and is the third most common reason for consultation in Australian general practice. A thorough history and examination can identify the minority of patients who require urgent neuroimaging or other targeted investigations. Careful correlation of clinical and radiological findings is required when abnormal neurological findings are detected. Radiological investigations may detect abnormalities at multiple levels but cannot confirm which level is primarily responsible for a patient's symptoms. A trial of conservative treatment is appropriate, even in cases of radiculopathy. Most patients with an acute episode of back pain recover within 6-12 weeks, but at least a third go on to have a recurrent episode within 1 year. Various invasive treatments, such as transforaminal steroid injection and discectomy, may speed up recovery from radiculopathy, but the long-term benefits of invasive treatment are uncertain.

Posterior projecting carotid bifurcation aneurysms.

Posteriorly projecting carotid bifurcation aneurysms are rare. Proximal anterior cerebral artery aneurysms are even more uncommon. Distinguishing between true posteriorly projecting carotid bifurcation aneurysms and carotid A1 aneurysms can be difficult but it is important because small posteriorly projecting carotid bifurcation aneurysms may need a contralateral approach for adequate exposure. We report our experience with a recent case that illustrated this problem.

Treatment of multiple arteriovenous malformations in pediatric patients with hereditary hemorrhagic telangiectasia and spontaneous hemorrhage. Report of two cases.

Due to inheritance of an autosomal dominant genetic mutation, patients with hereditary hemorrhagic telangiectasia (HTT) have an increased risk of harboring a cerebral arteriovenous malformation (AVM). They are also significantly more likely to have multiple AVMs. The natural history of AVMs in patients with HHT as well as their rate of hemorrhage is not clearly defined. Furthermore, spontaneous regression of such lesions has been reported. Treatment of cerebral AVMs in patients with HHT presents a particular challenge, especially with detection of incidental lesions following screening of asymptomatic patients. The management of HHT in two pediatric patients in whom hemorrhaging from a cerebral AVM occurred but who also had other lesions is presented here. Both patients were treated with stereotactic radiosurgery.

Objective monitoring of papilloedema using confocal scanning laser ophthalmoscopy.

Idiopathic intracranial hypertension can cause severe optic nerve damage with irreversible visual loss. Heidelberg retina tomography is a sensitive and reproducible tool that can be used in the monitoring of optic disc swelling due to IIH. We demonstrate that the three-dimensional images produced are easy to interpret, indicate progression or resolution and improve the timing of intervention in multidisciplinary settings by facilitating communication between specialists.

Surgical treatment of nocardial brain abscesses.

OBJECTIVE: Nocardial brain abscesses are associated with significant morbidity and mortality rates. The optimal management remains unclear. We reviewed the surgical outcomes of patients treated with a relatively uniform policy at a single institution. METHODS: Eleven patients were treated at the Royal Adelaide Hospital between 1970 and 2001. Their clinical presentations, surgical treatment, and outcomes were reviewed. RESULTS: Clinical presentations most frequently involved focal neurological deficits (91%). Predisposing factors were identified for 63% of the patients. Nine patients were treated only with aspiration and long-term chemotherapy. Two patients underwent craniotomy and lesion excision. The majority of patients required either one or two procedures. There were no deaths in this series. Management complications were observed for three patients. Abscess aspiration was complicated by parenchymal hemorrhage and ventriculitis for one patient and temporary worsening of hemiparesis for two patients. CONCLUSION: Our results suggest that aspiration alone (repeated as clinically indicated) is a safe, efficacious treatment for the majority of patients with nocardial brain abscesses.

Traumatic aneurysm of the callosomarginal artery.

Intracranial aneurysms are rare complications of head injury. The primary goals in the management of patients harbouring these lesions are early identification and intervention to prevent bleeding or rebleeding. The authors present a case of traumatic false aneurysm of the callosomarginal artery which was diagnosed following head injury and managed successfully with a good outcome.

Cranio-cervical decompression and expansile duroplasty for isolated fourth ventricle in a patient with Chiari II malformation.

The management of isolated fourth ventricle in Chiari II malformation remains a complex challenge. Commonly accepted treatment options have been associated with high rates of complications and failure. Cranio-cervical decompression and autologous expansile duroplasty may be an effective primary intervention for this condition.

Stereotactic radiosurgery for acoustic neuromas: what happens long term?

PURPOSE: To determine the clinical outcomes for acoustic neuroma treated with low-dose linear accelerator stereotactic radiosurgery (SRS) >10 years earlier at the Royal Adelaide Hospital using data collected prospectively at a dedicated SRS clinic. METHODS AND MATERIALS: Between November 1993 and December 2000, 51 patients underwent SRS for acoustic neuroma. For the 44 patients with primary SRS for sporadic (unilateral) lesions, the median age was 63 years, the median of the maximal tumor diameter was 21 mm (range, 11-34), and the marginal dose was 14 Gy for the first 4 patients and 12 Gy for the other 40. RESULTS: The crude tumor control rate was 97.7% (1 patient required salvage surgery for progression at 9.75 years). Only 8 (29%) of 28 patients ultimately retained useful hearing (interaural pure tone average ≤50 dB). Also, although the Kaplan-Meier estimated rate of hearing preservation at 5 years was 57% (95% confidence interval, 38-74%), this decreased to 24% (95% confidence interval, 11-44%) at 10 years. New or worsened V and VII cranial neuropathy occurred in 11% and 2% of patients, respectively; all cases were transient. No case of radiation oncogenesis developed. CONCLUSIONS: The long-term follow-up data of low-dose (12-14 Gy) linear accelerator SRS for acoustic neuroma have confirmed excellent tumor control and acceptable cranial neuropathy rates but a continual decrease in hearing preservation out to ≥10 years.

Lessons from a 17-year radiosurgery experience at the Royal Adelaide Hospital.

PURPOSE: To illustrate some of the potential pitfalls of cranial stereotactic radiosurgery (SRS) and its planning based on prospectively gathered data from a 17-year experience at the Royal Adelaide Hospital. METHODS AND MATERIALS: More than 250 treatments have been planned since 1993 using previously described standard SRS techniques for intracranial benign and malignant lesions. RESULTS: Five case studies are presented (1 meningioma, 1 acoustic neuroma, 2 solitary brain metastasis, 1 arteriovenous malformation), each of which demonstrates at least one salutary lesson. CONCLUSIONS: Because SRS delivers a highly conformal dose distribution, it is unforgiving of any geographic miss due to inaccurate outlining and thus dependent on neuroradiological expertise and collaboration. There are also potentially significant implications of misdiagnosis in SRS cases without histological proof--in particular, presumed brain metastases.

A surgical model of permanent and transient middle cerebral artery stroke in the sheep.

BACKGROUND: Animal models are essential to study the pathophysiological changes associated with focal occlusive stroke and to investigate novel therapies. Currently used rodent models have yielded little clinical success, however large animal models may provide a more suitable alternative to improve clinical translation. We sought to develop a model of acute proximal middle cerebral artery (MCA) ischemic stroke in sheep, including both permanent occlusion and transient occlusion with reperfusion. MATERIALS AND METHODS: 18 adult male and female Merino sheep were randomly allocated to one of three groups (n = 6/gp): 1) sham surgery; 2) permanent proximal MCA occlusion (MCAO); or 3) temporary MCAO with aneurysm clip. All animals had invasive arterial blood pressure, intracranial pressure and brain tissue oxygen monitoring. At 4 h following vessel occlusion or sham surgery animals were killed by perfusion fixation. Brains were processed for histopathological examination and infarct area determination. 6 further animals were randomized to either permanent (n = 3) or temporary MCAO (n = 3) and then had magnetic resonance imaging (MRI) at 4 h after MCAO. RESULTS: Evidence of ischemic injury in an MCA distribution was seen in all stroke animals. The ischemic lesion area was significantly larger after permanent (28.8%) compared with temporary MCAO (14.6%). Sham animals demonstrated no evidence of ischemic injury. There was a significant reduction in brain tissue oxygen partial pressure after permanent vessel occlusion between 30 and 210 mins after MCAO. MRI at 4 h demonstrated complete proximal MCA occlusion in the permanent MCAO animals with a diffusion deficit involving the whole right MCA territory, whereas temporary MCAO animals demonstrated MRA evidence of flow within the right MCA and smaller predominantly cortical diffusion deficits. CONCLUSIONS: Proximal MCAO can be achieved in an ovine model of stroke via a surgical approach. Permanent occlusion creates larger infarct volumes, however aneurysm clip application allows for reperfusion.

Radiosurgery for brain metastases at the Royal Adelaide Hospital: are we treating the right patients?

Although non-randomized data strongly suggest improved outcome from radiosurgery (RS) for brain metastases relative to whole brain radiotherapy (WBRT) alone, selection factors account for much of the observed differences. This retrospective review of the 16 brain metastases patients treated so far with RS at the Royal Adelaide Hospital confirms a median survival of 10.1 months, consistent with recent multi-institutional pooled results and significantly longer than the median survival of 3-6 months typically reported for WBRT alone. The emerging randomized trials comparing surgery, RS and WBRT for brain metastases are reviewed in the context of the Radiation Therapy Oncology Group Recursive Partitioning Analysis prognostic Class concept in order to assess whether we are using this resource intensive technique to treat the 'right' patients. We conclude that it is reasonable to continue our current policy of considering RS primarily for patients of good performance status with solitary brain metastases. We have a flexible approach to adjuvant WBRT which appears to decrease brain relapse, but not improve survival.

Rhabdoid glioblastoma: a case report.

The authors report a 16 year old girl with a supratentorial rhabdoid glioblastoma. The radiological features, histopathology and management of this rare variant of glioblastoma multiforme are discussed.