Spasticity secondary to Leigh syndrome managed with selective dorsal rhizotomy: a case report.

PURPOSE: Selective dorsal rhizotomy (SDR) is a surgical technique used to treat spasticity in children secondary to cerebral palsy (CP). METHOD: We report, to the best of our knowledge for the first time, the case of a child who underwent SDR for the management of spasticity secondary to Leigh syndrome. RESULT: SDR resulted in excellent functional outcome with significant improvement in spasticity. This result contributes to the mounting evidence that SDR could be used to alleviate spasticity secondary not only to CP but also to other pathologies as well.

A wearable headset for monitoring electromyography responses within spinal surgery.

PURPOSE: This research examines an approach for enhancing the efficiency of spinal surgery utilising the technological capabilities and design functionalities of wearable headsets, in this case Google Glass. The aim was to improve the efficiency of the selective dorsal rhizotomy neurosurgical procedure initially through the use of Glass via an innovative approach to information design for an intraoperative monitoring display. METHODS: Utilising primary and secondary research methods the development of a new electromyography response display for a wearable headset was undertaken. RESULTS: Testing proved that Glass was fit for purpose and that the new intraoperative monitor design provided an example platform for the innovative intraoperative monitoring display; however, alternative wearable headsets such as the Microsoft HoloLens could also be equally viable. CONCLUSION: The new display design combined with the appropriate wearable technology could greatly benefit the selective dorsal rhizotomy procedure.

Excellent functional outcome following selective dorsal rhizotomy in a child with spasticity secondary to transverse myelitis.

PURPOSE: Selective dorsal rhizotomy (SDR) is a neurosurgical procedure used to treat spasticity in children with cerebral palsy (CP). The vast majority of studies to date suggest SDR is particularly effective in reducing lower limb spasticity in spastic diplegia with long-lasting effect. METHOD: We report, to the best of our knowledge for the first time, the case of a teenager who underwent SDR for the management of spasticity secondary to transverse myelitis. RESULTS: This is an unusual indication for SDR which resulted in completely loose lower limbs and an excellent functional outcome. At a follow-up 18 months following the procedure, the child had no re-occurrence of his symptoms. CONCLUSION: This report raises the possibility that the use of SDR could be expanded to include other pathologies. We discuss the case and the relevant literature. Our spasticity service at NUH has to date inserted 300 baclofen pumps and performed 60 SDRs mainly in children with cerebral palsy.

4-dimensional local radial basis function interpolation of large, uniformly spaced datasets.

BACKGROUND AND OBJECTIVE: Large, uniformly spaced, complex and time varying datasets derived from high resolution medical image velocimetry can provide a wealth of information regarding small-scale transient physiological flow phenomena and pulsation of anatomical boundaries. However, there remains a need for interpolation techniques to effectively reconstruct a fully 4-dimensional functional relationship from this data. This paper presents a preliminary evaluation of a 4-dimensional local radial basis function (RBF) algorithm as a means of addressing this problem for laminar flows. METHODS: A 4D interpolation algorithm is proposed based on a Local Hermitian Interpolation (LHI) using a combination of multi-quadric RBF with a partition of unity scheme. The domain is divided into uniform sub-systems with size restricted to immediately neighbouring points. The validity of the algorithm is first established on a known 4D analytical dataset and a CFD based laminar flow phantom. Application is then demonstrated through characterisation of a large 4D laminar flow dataset obtained from magnetic resonance imaging (MRI) measurements of cerebrospinal fluid velocities in the brain. RESULTS: Performance of the algorithm is compared to that of a quad-linear interpolation, demonstrating favourable improvement in accuracy. The technique is shown to be robust, computationally efficient and capable of refined interpolation in Euclidean space and time. Application to MR velocimetry data is shown to produce promising results for the 4D reconstruction of the transient flow field and movement of the fluid boundaries at spatial and temporal locations intermediate to the original data. CONCLUSION: This study has demonstrated feasibility of an accurate, stable and efficient 4-dimensional local RBF interpolation method for large, transient laminar flow velocimetry datasets. The proposed approach does not suffer from ill-conditioning or high computational cost due to domain decomposition into local stencils where the RBF is only ever applied to a limited number of points. This work offers a potential tool to assist medical diagnoses and drug delivery through better understanding of physiological flow fields such as cerebrospinal fluid. Further work will evaluate the technique on a wider range of flow fields and against CFD simulation.

Intrathecal chemotherapy delivered by a lumbar-thecal catheter in metastatic medulloblastoma: a case illustration.

BACKGROUND: Medulloblastoma is the most common malignant brain tumour in children. Despite recent advances, the prognosis in high risk patients remains poor. Further improvement in survival is dependent upon the development of strategies to attack the tumour more effectively, but with less toxicity. Intrathecal chemotherapy, is an ideal but currently underused method of directly targeting residual tumour within the area of resection and the leptomeningeal disease commonly associated with this tumour. METHOD: We describe the case of a 12 yr old child with metastatic medulloblastoma, who received intrathecal topotecan via a spinal catheter. CONCLUSION: This method represents a simple, safe and effective method of delivering an even and widespread distribution of drug within the cerebrospinal fluid (CSF) of the neuroaxis. With new agents being identified and others in the early stages of development, intrathecal chemotherapy may emerge as an important therapeutic option to consider when faced with such challenging cases.

Three-dimensional cerebrospinal fluid flow within the human ventricular system.

Cerebrospinal fluid (CSF) is a Newtonian fluid and can, therefore, be modelled using computational fluid dynamics (CFD). Previous modelling of the CSF has been limited to simplified geometric models. This work describes a geometrically accurate three dimensional (3D) computational model of the human ventricular system (HVS) constructed from magnetic resonance images (MRI) of the human brain. It is an accurate and full representation of the HVS and includes appropriately positioned CSF production and drainage locations. It was used to investigate the pulsatile motion of CSF within the human brain. During this investigation CSF flow rate was set at a constant 500 ml/day, to mimic real life secretion of CSF into the system, and a pulsing velocity profile was added to the inlets to incorporate the effect of cardiac pulsations on the choroid plexus and their subsequent influence on CSF motion in the HVS. Boundary conditions for the CSF exits from the ventricles (foramina of Magendie and Lushka) were found using a "nesting" approach, in which a simplified model of the entire central nervous system (CNS) was used to examine the effects of the CSF surrounding the ventricular system (VS). This model provided time varying pressure data for the exits from the VS nested within it. The fastest flow was found in the cerebral aqueduct, where a maximum velocity of 11.38 mm/s was observed over five cycles. The maximum Reynolds number recorded during the simulation was 15 with an average Reynolds number of the order of 0.39, indicating that CSF motion is creeping flow in most of the computational domain and consequently will follow the geometry of the model. CSF pressure also varies with geometry with a maximum pressure drop of 1.14 Pa occurring through the cerebral aqueduct. CSF flow velocity is substantially slower in the areas that are furthest away from the inlets; in some areas flow is nearly stagnant.

A virtual reality surgery simulation of cutting and retraction in neurosurgery with force-feedback.

A virtual-reality surgical simulator aimed at neurosurgery is presented. The simulator utilises boundary element (BE) technology to develop real-time realistic deformable models of the brain. The simulator incorporates the simulation of surgical prodding, pulling and cutting. Advanced features include the separation the cut surfaces by retractors and post-cutting deformations. The experience of virtual surgery is enhanced by implementing 3D stereo-vision and the use of two hand-held force-feedback devices.

Rigid-body modelling of shaken baby syndrome.

Recent reassessment of the literature on the shaken baby syndrome (SBS) has revealed a lack of scientific evidence and understanding of all aspects of the syndrome. In particular, studies have been unable to clarify the mechanisms of injury, indicating that impact, rather than shaking alone, is necessary to cause the type of brain damage observed. Rigid-body modelling (RBM) was used to investigate the effect of neck stiffness on head motion and head-torso impacts as a possible mechanism of injury. Realistic shaking data obtained from an anthropometric test dummy (ATD) was used to simulate shaking. In each study injury levels for concussion were exceeded, though impact-type characteristics were required to do so in the neck stiffness study. Levels for the type of injury associated with the syndrome were not exceeded. It is unlikely that further gross biomechanical investigation of the syndrome will be able to significantly contribute to the understanding of SBS. Current injury criteria are based on high-energy, single-impact studies. Since this is not the type of loading in SBS it is suggested that their application here is inappropriate and that future studies should focus on injury mechanisms in low-energy cyclic loading.

Solitary dorsal intramedullary schwannoma. Case report.

A case of solitary dorsal intramedullary schwannoma diagnosed by magnetic resonance imaging and treated surgically is reported. The authors review the previously published cases. The possible etiology of the tumor as well as some difficulties encountered in the diagnostic procedure and treatment are discussed.

Monstrous skull osteomas in a probable Gardner's syndrome: case report.

BACKGROUND: Gardner's syndrome includes a clinical triad of familial polyposis coli, osteomas, and soft tissue tumors. METHODS: We present a very unusual case of probable isolated Gardner's syndrome characterized by extremely voluminous osteomas in the occipital and frontal areas associated with diffuse subcutaneous lipomas and without colic abnormality. RESULTS: The neurosurgical management included resection of the osteomas for cosmetic reasons. After a follow-up period of 5 years, the patient remains free of digestive complaints and the resected osteomas did not recur. CONCLUSIONS: The special clinical presentation of our case of possible Gardner's syndrome is discussed.

Spinal arachnoiditis mimicking a spinal cord tumor: a case report and review of the literature.

We report on an unusual case of idiopathic arachnoiditis mimicking a spinal cord tumor in a 50-year-old man with progressive paraparesis. The medical imaging work-up showed an enlarged terminal cone with adjacent cysts. Although there was no enhancement of the terminal cone or the surrounding structures, the diagnosis of spinal cord tumor was maintained and surgery was carried out. Exploration of the cauda equina and the tissue surrounding the terminal cone did not reveal a tumor. The patient improved dramatically after surgery but the symptoms recurred 1 year later. We review arachnoiditis, its pathology, and its treatment with special attention drawn to the primary form of spinal arachnoiditis.

Neuroendoscopic third ventriculostomy for hydrocephalus in adults: report of a single unit's experience with 63 cases.

BACKGROUND: Neuroendoscopic third ventriculostomy (NTV) is becoming a first line treatment for hydrocephalus in this center. Its use in a consecutive series of adults is reported. METHOD: Initially a retrospective data collection after 7 months becoming prospective studying all patients who underwent NTV in this center. The adults (17 years or older) have been studied. RESULTS: Sixty-three patients met the criteria for inclusion: 38 male, 25 female. Mean age at first NTV 37.5 years. There was an 80% success rate (i.e., no further therapy for the hydrocephalus required). Follow-up was for a mean of 3.1 years. The largest subgroup were patients with third ventricular tumours (35%), of whom 86% were successfully treated. Mean time to failure for the whole series was 8.5 months (range immediate--30 months). Complications occurred in 17.5%; those deemed serious in 11%. There were three deaths (4.7%) within 30 days of the procedure. There were six other deaths during follow-up, five because of tumour progression and one because of pneumonia. CONCLUSIONS: This procedure lends itself to the treatment of hydrocephalus in adults and appears to be more successful than in young children. It is efficacious in both previously shunted and non shunted patients. It is now the first-line treatment for noncommunicating hydrocephalus in this center and also for patients with shunt failure who are anatomically suitable, having cerebrospinal fluid spaces large enough to admit the endoscope. The complication and mortality rates compare favorably with those for shunts.

Improved safety of neuroendoscopic third ventriculostomy by using an operative Doppler ultrasound probe. Technical note.

In this paper the authors describe the use of a Doppler device, originally built for intravascular use, that is passed through a flexible neuroendoscope during a neuroendoscopic third ventriculostomy (NTV) procedure to treat for hydrocephalus. There was no morbidity associated with the use of this Doppler probe, and the procedure was not significantly lengthened. The Doppler probe was very accurate in locating the position of the basilar artery tip and assured the safety of NTV.

Soft tissue rapid prototyping in neurosurgery.

As part of our research into the fluid hydrodynamics of the human ventricular system, a fused deposition model of the human ventricular system was made using magnetic resonance imaging (MRI) data. This article describes the manufacturing of a positive cast of the ventricles as a first step in the construction of a hollow model. After decryption of the original MRI file (ACR-Nema format), the MRI slices were reassembled semiautomatically and a rapid prototyping station produced a resin model. Because of its ease and speed, this method harbors great potential for teaching purposes, research, and preoperative planning in complex three-dimensional soft tissue targets.

Posttraumatic rupture of the thoracic aorta.

Ten patients with traumatic lesions of the thoracic aorta were seen in a hospital. Most were victims of traffic accidents and presented severe associated lesions along with their vascular trauma. We found that the vascular injuries were clinically manifest in only a minority of patients. The remaining ruptures were discovered through CT-scanning of the mediastinum or angiography. We believe that in every major trauma victim aortic lesions should be actively sought for by complimentary examinations to guarantee maximum survival of the patients.

A patient with two upper lumbar disc herniations.

Of all lumbar disc herniations, less than 5% occur in the upper lumbar area. Though protrusions are common at all levels, truly extruded disc herniations in the upper lumbar area from L1 to L3 are rare. Even more unusual is the multilevel occurrence of herniations in this area. The authors stress the importance of accurate diagnosis and clinically directed medical imaging work-ups.

The role of intrathecal baclofen in the management of primary and secondary dystonia in children.

Intrathecal baclofen (ITB) is a well-established method of treating spasticity in children with cerebral palsy. In our series, eight children with primary or dystonia secondary to cerebral palsy have benefited from ITB. The observations in this paper are subjective and based on the carer's impressions, but have confirmed the role of ITB in dystonia. Children with dystonia secondary to cerebral palsy benefited most and ITB can be used in these as a single treatment modality. The approach is different in dystonia secondary to cerebral palsy, where ITB can be used to palliate the spastic component, but other methods are necessary to treat the primary disease. We currently have three children in our series, where ITB in conjunction with deep brain stimulation (DBS) was used with satisfactory results.

Virtual neurosurgery, training for the future.

Virtual reality (VR) simulators have been created for various surgical specialties. The common theme is extensive use of graphics, confined spaces, limited functionality and limited tactile feedback. A development team at the University of Nottingham, UK, consisting of computer scientists, mechanical engineers, graphic designers and a neurosurgeon, set out to develop a haptic, e.g. tactile simulator for neurosurgery making use of boundary elements (BE). The relative homogeneity of the brain, allows boundary elements, e.g. 'surface only' rendering, to simulate the brain structure. A boundary element simplifies the computing equations saves computing time, by assuming the properties of the surface equal the properties of the body. A limited audit was done by neurosurgical users confirming the potential of the simulator as a training tool. This paper focuses on the application of the computational method and refers to the underlying mathematical structure. Full references are included regarding the mathematical methodology.