Our Management of Vestibular Schwannomas and Review of Literatures

There is no a clear consensus provided in the literature and there remain controversial on the treatment especially for small to medium size Vestibular schwannomas (VSs). Thus the treatment technique and approach preference vary from centre to centre. This problem too exists in our centre. The purpose of this paper is to develop a consensus in our hospital among our colleagues on the treatment of our VSs patients. We have been treating VSs patient by translabyrinthine approach from time to time for the last 5 years and found it to be a very efficient approach. This approach gives the most direct route to the tumor with excellent exposure of the internal acoustic meatus, cerebropontine angle (CPA) area without the need to retract the brain with facial nerve totally in control early in the surgery. The only problem was, when there is large posterior fossa component of the tumor present. This approach is safe with direct exposure to CPA area and have minimum intraoperative or postoperative complications.

Data fusion and 3D visualization for optimized representation of neurovascular relationships in the posterior fossa

Background Reliable 3D visualization of neurovascular relationships in the posterior fossa at the surface of the brainstem is still critical due to artifacts of imaging. To assess neurovascular compression syndromes more reliably, a new approach of 3D visualization based on registration and fusion of high-resolution MR data is presented. Methods A total of 80 patients received MRI data with 3D-CISS and 3D-TOF at 3.0 Tesla. After registration and subsequent segmentation, the vascular information of the TOF data was fused into the CISS data. Two 3D visualizations were created for each patient, one before and one after fusion, which were verified with the intraoperative situation during microvascular decompression (MVD). The reproduction quality of vessels was evaluated with a rating system. Results In all cases, the presented approach compensated for typical limitations in the 3D visualization of neurovascular compression such as the partial or complete suppression of larger vessels, suppression of smaller vessels at the CSF margin, and artifacts from heart pulsation. In more than 95% of the cases of hemifacial spasm and glossopharyngeal neuralgia, accurate assessment of the compression was only possible after registration and fusion. In more than 50% of the cases with trigeminal neuralgia, the presented approach was crucial to finding the actually offending vessel. Conclusions 3D visualization of fused image data allows for a more complete representation of the vessel-nerve situation. The results from this approach are reproducible and the assessment of neurovascular compression is safer. It is a powerful tool for planning MVD.

Improved prediction of postoperative paediatric cerebellar mutism syndrome using an artificial neural network

Background Postoperative paediatric cerebellar mutism syndrome (pCMS) is a common but severe complication which may arise following the resection of posterior fossa tumours in children. Two previous studies have aimed to preoperatively predict pCMS, with varying results. In this work, we examine the generalisation of these models and determine if pCMS can be predicted more accurately using an artificial neural network (ANN). Methods An overview of reviews was performed to identify risk factors for pCMS, and a retrospective dataset collected as per these defined risk factors from children undergoing resection of primary posterior fossa tumours. The ANN was trained on this dataset and its performance evaluated in comparison to logistic regression and other predictive indices via analysis of receiver operator characteristic curves. Area under the curve (AUC) and accuracy were calculated and compared using a Wilcoxon signed rank test, with p<0.05 considered statistically significant. Results 204 children were included, of whom 80 developed pCMS. The performance of the ANN (AUC 0.949; accuracy 90.9%) exceeded that of logistic regression (p<0.05) and both external models (p<0.001). Conclusion Using an ANN, we show improved prediction of pCMS in comparison to previous models and conventional methods.

Evaluating predictors of successful postoperative day 1 discharge following posterior fossa tumor resection

INTRODUCTION: Current trends in surgical neuro-oncology have shown that early discharges are both safe and feasible with shorter lengths of stay (LOS) associated with fewer thromboembolic complications, less hospital-acquired infections, reduced costs, and greater patient satisfaction. Traditionally, infratentorial tumor resections have been associated with longer LOS and limited data exists evaluating predictors of early discharge in these patients. The objective was to assess patients undergoing posterior fossa craniotomies for tumor resection and identify variables associated with a postoperative day 1 (POD1) discharge and determine any differences in outcomes and readmission rates. METHODS: A retrospective review of posterior fossa craniotomies for tumor resection at our institution was performed from 2011 to 2020. Laser ablations, craniotomies for non-tumoral pathologies, and biopsies were excluded. Complete demographic, clinical, surgical and postoperative data was collected for each patient. RESULTS: 173 patients were identified and 25 (14.5%) were discharged on POD1. Median length of stay was 6 days. The POD1 discharges had significantly better preoperative Karnofsky performance scores (p<0.001) and modified Rankin scores (p=0.002) and less frequently presented emergently (p=0.006) or with preoperative neurologic deficits (p=0.021). No statistically significant difference in 30-day readmissions and rates of PE, UTI, and DVT were found between the POD1 discharge cohort and those discharged later. Univariate logistic regression identified better preoperative functional status, elective admission, and lack of preoperative hydrocephalus as independent predictors of POD1 discharge however only the latter remained significant in the multivariable model (p=0.001). CONCLUSIONS: Discharging patients on POD1 is feasible following posterior fossa tumor resections and does not introduce any significant undue risk or result in higher readmissions. Although we found that the only independent predictor for a longer LOS was preoperative hydrocephalus, larger, prospective studies are needed to confirm these findings.

Sensory and motor electrophysiological mapping of the cerebellum in humans

Cerebellar damage during posterior fossa surgery in children can lead to ataxia and risk of cerebellar mutism syndrome. Compartmentalisation of sensorimotor and cognitive functions within the cerebellum have been demonstrated in animal electrophysiology and human imaging studies. Electrophysiological monitoring was carried out under general anaesthesia to assess the limb sensorimotor representation within the human cerebellum for assessment of neurophysiological integrity to reduce the incidence of surgical morbidities. Thirteen adult and paediatric patients undergoing posterior fossa surgery were recruited. Sensory evoked field potentials were recorded in response to mapping (n = 8) to electrical stimulation of limb nerves or muscles. For motor mapping (n = 5), electrical stimulation was applied to the surface of the cerebellum and evoked EMG responses were sought in facial and limb muscles. Sensory evoked potentials were found in two patients (25%). Responses were located on the surface of the right inferior posterior cerebellum to stimulation of the right leg in one patient, and on the left inferior posterior lobe in another patient to stimulation of left forearm. No evoked EMG responses were found for the motor mapping. The present study identifies challenges with using neurophysiological methods to map functional organization within the human cerebellum and considers ways to improve success.

A rare combination of post-ductal coarctation of the aorta and adjunct tortuous aneurysm: a neonate with Posterior fossa anomalies, Haemangiomas of the head and neck, Arterial, Cardiovascular, and Eye anomalies and ventral developmental defect syndrome

A 4-day-old girl with Posterior fossa anomalies, Haemangiomas of the head and neck, Arterial, Cardiovascular, and Eye anomalies and ventral developmental defect syndrome comprising a facial haemangioma, aortic coarctation at the aortic arch, torturous aortic aneurysm distal to coarctation, and ductus arteriosus originating proximal to the coarctation is presented. The aortic arch was successfully reconstructed without cardiopulmonary bypass, and she is currently doing well after 4 years and 8 months.

Solitary bone plasmacytoma as posterior fossa cranial neoplasia, presentation of two clinical cases

Background: Solitary bone plasmacytoma is a plasmatic cell dyscrasia; its presentation in the posterior fossa is very rare. Case Description: We present two cases, a 59-year-old male and a 50-year-old female, both with heterogeneous clinical presentation. One had symptoms compatible with endocranial hypertension, and the other presented with a hemispheric cerebellar syndrome and ipsilateral trigeminal neuralgia. They were both related to an intraosseous tumor of the occipital region near the torcula with large extension to the posterior fossa. The diagnosis of a plasma cell neoplasm arising from the diploe of the squamous portion of the occipital bone was confirmed with immunohistochemistry. Conclusion: The treatment for a cranial tumor that is suspected to be a solitary bone plasmacytoma requires a multidisciplinary team to diagnose, plan a total resection, and after surgery continue with the follow-up of the patient. Solitary bone plasmacytoma should be considered as a differential diagnosis for a tumor that produces cancellous bone widening without sclerotic borders.