Rasheed Zakaria

Atypical meningoma: current management dilemmas and prospective clinical trials

Atypical meningioma is an intermediate grade tumour with a greater risk of recurrence following surgical resection. Changes to the WHO classification have resulted in an increased reporting of these tumours. The role of early adjuvant radiotherapy after gross total resection has not been clearly defined and the literature evidence is of poor quality providing conflicting information. This review assesses the evidence for current clinical practice, management dilemmas and the need for prospective clinical trials for atypical meningioma.

Conservative management of type II and III odontoid fractures in the elderly at a regional spine centre: A prospective and retrospective cohort study.

Abstract Background. The optimal management of odontoid fractures in the elderly population is unclear and management of this group of patients is complicated by multiple co-morbidities. This study aimed to determine the outcomes after conservative management strategies were applied in this patient group. Methods. We carried out retrospective and prospective analyses of all patients with axial cervical spine injuries, at a single centre. We included patients aged over 60 years with type II and III odontoid fractures. Information was gathered on demographics, ASA grading-associated injuries and complications. The outcome measures were rates and type of union, pain and neurological functions, specifically ambulation. Results. Fifty-seven adult patients with a median age of 78 years (range 60–92 years) were included. There were 42 type II and 15 type III odontoid fractures. Three patients required surgical fixation due to displaced fractures, which could not be reduced with manual traction. Twenty-four (41%) patients were managed with a rigid pinned halo orthosis to obtain adequate reduction and immobilisation. The remaining 30 (53%) were managed in a hard cervical collar. Patients managed with a halo were significantly younger and had more associated injuries than patients managed in a collar (age: t-test = 4.05, p < 0.01, associated injuries: Chi-square = 4.38, p < 0.05). At a mean follow-up of 25 weeks, 87% of type II and 100% of type III fractures had achieved bony union or stable, fibrous non-union. There were no statistical differences in fracture type, follow-up or neurological outcomes between the halo and collar groups. However, overall more patients managed in a collar developed stable fibrous non-union than bony fusion (Fishers exact test, p < 0.05), although this was not significant when analysed by each fracture type individually. A regression model was constructed and identified fracture type as the only independent predictor of time to union, with type III fractures healing faster than type II. Conclusions. High rates of bony union and stable fibrous non-union with a good functional outcome can be achieved in the elderly population sustaining type II or III odontoid fractures, when managed non-surgically. Halo orthosis may not offer any clear advantage over hard collar in this group. Close follow-up is needed for late complications and there must be a willingness to perform surgery if conservative measures fail.

Raised intracranial pressure and hydrocephalus following hindbrain decompression for Chiari I malformation: a case series and review of the literature‡

Object. Chiari-syringomyelia is a heterogeneous condition that may be treated by decompression of the foramen magnum. Raised intracranial pressure (ICP) and/or hydrocephalus is a rare complication of this treatment. We aim to describe the incidence, clinical presentation, radiographic findings, management and outcome of patients developing raised ICP and/or hydrocephalus after hindbrain decompression for Chiari I malformation. Methods. Retrospective analysis of 138 consecutive adult and paediatric patients with Chiari I malformation who underwent foramen magnum decompression. Results. The incidence of post-operative symptomatic raised ICP and/or hydrocephalus in this series was 8.7%. Overall, 9 of 12 patients developing raised ICP or hydrocephalus required a VP shunt, an overall incidence of 6.5%. However, 3 of 12 patients were successfully managed with external ventricular drainage or conservatively. Presentation was with headache or CSF wound leak at a median of 13 days post-operatively. Subdural hygromata were observed in five cases in association with hydrocephalus and urgent drainage to relieve mass effect was required in two cases. At a mean follow up of 36 months, 9 of 12 patients were asymptomatic. Conclusions. There is a risk of requiring a permanent VP shunt associated with decompression for Chiari I even in the absence of ventriculomegaly or signs of raised ICP pre-operatively. Patients presenting with new symptoms or CSF wound leak following FMD mandate investigation to exclude hydrocephalus, raised ICP or subdural hygroma.

The role of magnetic resonance imaging in the management of brain metastases: diagnosis to prognosis

This article reviews the different MRI techniques available for the diagnosis, treatment and monitoring of brain metastases with a focus on applying advanced MR techniques to practical clinical problems. Topics include conventional MRI sequences and contrast agents, functional MR imaging, diffusion weighted MR, MR spectroscopy and perfusion MR. The role of radiographic biomarkers is discussed as well as future directions such as molecular imaging and MR guided high frequency ultrasound.

Diffusion-weighted MRI characteristics of the cerebral metastasis to brain boundary predicts patient outcomes

BackgroundDiffusion-weighted MRI (DWI) has been used in neurosurgical practice mainly to distinguish cerebral metastases from abscess and glioma. There is evidence from other solid organ cancers and metastases that DWI may be used as a biomarker of prognosis and treatment response. We therefore investigated DWI characteristics of cerebral metastases and their peritumoral region recorded pre-operatively and related these to patient outcomes.MethodsRetrospective analysis of 76 cases operated upon at a single institution with DWI performed pre-operatively at 1.5T. Maps of apparent diffusion coefficient (ADC) were generated using standard protocols. Readings were taken from the tumor, peritumoral region and across the brain-tumor interface. Patient outcomes were overall survival and time to local recurrence.ResultsA minimum ADC greater than 919.4 × 10-6 mm2/s within a metastasis predicted longer overall survival regardless of adjuvant therapies. This was not simply due to differences between the types of primary cancer because the effect was observed even in a subgroup of 36 patients with the same primary, non-small cell lung cancer. The change in diffusion across the tumor border and into peritumoral brain was measured by the “ADC transition coefficient” or ATC and this was more strongly predictive than ADC readings alone. Metastases with a sharp change in diffusion across their border (ATC >0.279) showed shorter overall survival compared to those with a more diffuse edge. The ATC was the only imaging measurement which independently predicted overall survival in multivariate analysis (hazard ratio 0.54, 95% CI 0.3 – 0.97, p = 0.04).ConclusionsDWI demonstrates changes in the tumor, across the tumor edge and in the peritumoral region which may not be visible on conventional MRI and this may be useful in predicting patient outcomes for operated cerebral metastases.

Management of Typical and Atypical Hangman's Fractures

Study Design Retrospective study of a prospectively maintained database. Objective Our aim was to retrospectively review management and outcomes of patients with low-grade hangmans fractures, specifically looking at differences in outcomes between collars and halo immobilization. We also studied fracture patterns and their treatment outcomes. Methods Forty-one patients with hangmans fractures were identified from 105 patients with axis fractures between 2007 and 2013. Typical hangmans fractures were defined as traumatic spondylolisthesis of the axis causing a bilateral pars interarticularis fracture. Fractures involving the posterior cortex of C2 on one or both sides or an asymmetrical pattern were defined as atypical. Results There were 41 patients with a mean age of 59 years, with 13 (31.7%) typical and 28 (68.2%) atypical fractures. There were 22 (53.6%) type 1 fractures, 7 (41.4%) type 2 fractures, and 2 (4.9%) type 2a fractures in this series. Cervical collars were used to manage 11 patients (27% of all patients with hangmans fractures) and halo orthosis was used in 27 (65.8%). Three (7.3%) patients underwent surgical fixation of the fracture. Bony union was achieved in all patients on radiologic follow-up. Permanent neurologic deficit occurred in one patient due to associated injuries. Neck pain and stiffness were reported more commonly in the atypical group, but this finding was not statistically significant. Conclusions The majority of hangman type fractures can be treated nonoperatively. We found no difference in outcomes between a rigid collar or halo immobilization for treatment of low-grade fractures. Radiologic follow-up is essential to identify cases of nonunion.

The reliability of routine clinical post-processing software in assessing potential diffusion-weighted MRI “biomarkers” in brain metastases

BACKGROUND AND PURPOSE Diffusion MRI characteristics have been used as biomarkers to guide prognosis in cerebral pathologies including brain metastases. The measurement of ADC is often described poorly in clinical and research studies with little detail given to the practical considerations of where to place ROIs, which post processing software package to use and how reproducible the resulting metrics will be. METHOD We investigated a series of 12 patients with brain metastases and preoperative DWI. Three post processing platforms were used. ROI were placed over the tumour, peritumoural region and across the brain-tumour interface. These recordings were made by a neurosurgeon and a neuroradiologist. Inter-intra-observer variability was assessed using Bland-Altman analysis. An exploratory analysis of DWI with overall survival and tumour type was made. RESULTS There was excellent correlation between the software packages used for all measures including assessing the whole tumour, selective regions with lowest ADC, the change of ADC across the brain-tumour interface and the relation of the tumour ADC to peritumoural regions and the normal white matter. There was no significant inter- or intra-observer variability for repeated readings. There were significant differences in the mean values obtained using different methodologies and different metrics had differing relationships to overall survival and primary tumour of origin. CONCLUSION Diffusion weighted MRI metrics offer promise as potential non-invasive biomarkers in brain metastases and a variety of metrics have been shown to be reliably measured using differing platforms and observers.

Prognostic Factors in Lobar World Health Organization Grade II Astrocytomas.

BACKGROUND World Health Organization grade II astrocytomas (AII) are the commonest low-grade glioma subset, but their prognostic factors are subject to debate. This institutional study aimed to identify prognostic factors in lobar AII. METHODS Retrospective review of newly diagnosed, lobar AII between 2006 and 2012. Patient demographics, imaging, and treatment data were obtained. Isocitrate dehydrogenase-1 (IDH1) status was assessed via immunohistochemistry. Multivariate analysis was performed with Cox regression to identify prognostic factors for overall survival (OS) and progression-free survival (PFS). RESULTS A total of 92 adult patients were identified with a median age of 42 years (range 20-73 years) and median follow-up period of 45 months (range, 7-98 months). Seizures were the commonest mode of presentation (75%). IDH1 immunopositivity was seen in 46 of 83 patients (55%). Radiology diagnosis agreed with histology in 76% of cases, and 28% of tumors had documented evidence of some degree of contrast enhancement. Surgical management was either resection (51%) or biopsy (49%) and postoperative radiotherapy was used in patients with unfavorable prognostic features. The median OS and PFS were 85 months (range 2-98 months) and 36 months (95% confidence interval [95% CI] 27-45 months), respectively. Surgical resection (P < 0.001; hazard ratio [HR] 5.072; 95% CI 2.050-12.550), absence of contrast enhancement (P = 0.006; HR 3.180; 95% CI 1.403-7.206), and IDH1 immunopositivity (P = 0.006; HR 3.310; 95% CI 1.416-7.738) were associated with improved OS. Good performance status (P = 0.005; HR 5.965; 95% CI 1.710-20.804) and absence of contrast enhancement (P < 0.001; HR 3.446; 95% CI 1.883-6.304) were associated with improved PFS. CONCLUSIONS Patients with World Health Organization grade II astrocytomas have better overall survival if their tumor is nonenhancing, amenable to surgical resection, and exhibits the IDH1 mutation. These factors should be used to guide patient management and inform prognosis.

Using ADC Maps with Structural Scans to Improve Intraoperative Biopsy Specimens in Brain Metastases

Brain metastases are increasingly common tumours but little is known about their biological mechanisms of local brain invasion in vivo. Samples across the leading edge are not easy to obtain using conventional neurosurgical methods as these tumours frequently show cysts, haemorrhage and necrosis. Apparent diffusion coefficient (ADC) maps were generated following diffusion-weighted imaging at 3T using b-values of 0 and 1000 second/mm2 and fused with a 1 mm slice fast spoiled gradient echo sequence. This fused image was used to guide intraoperative biopsies. The technique was performed in ten cases with excellent sampling of the brain-to-metastasis interface, gross total resection and no additional morbidity. Fusing ADC maps with structural scans for intraoperative neuronavigation is a useful method for sampling the leading edge of brain metastases.

Overtightening of halo pins resulting in intracranial penetration, pneumocephalus, and epileptic seizure

A 60-year-old man sustained an undisplaced type III odontoid fracture following a fall down a full flight of stairs. His medical history was remarkable for a partial pancreatectomy and splenectomy in 2006 for chronic pancreatitis. This had rendered him diabetic, on insulin, and he required long-term administration of penicillin V. The fracture was treated with a halo vest, and, unknowing of its potentially serious consequences, the patient continued to tighten the halo pins himself. He presented 1 month later following a witnessed seizure. A computed tomography scan was performed, which demonstrated 2 cranial perforations, with the halo pins penetrating the cranium and resultant pneumocephalus. He was started on antiepileptic medication and was placed in a pinless halo system. He had no further seizures and has made an uneventful neurological recovery. This paper serves to highlight the potential complications which may arise from the use of a halo vest. Proper patient education is essential to avoid these serious yet avoidable events, and patients with low bone density and the immunosuppressed should be monitored closely.