Michael G. Hart

Clinical associations of Dupuytren’s disease

Dupuytren’s disease (DD) is a common progressive fibrotic condition affecting the palmar and digital fascia. Although its management is undertaken by hand surgeons, it is commonly seen by other doctors as an incidental finding. In many cases it is believed to be associated with other medical conditions, although the evidence for such associations is not always clear. This review considers the evidence behind these associations and discusses the aetiology of DD. By doing so, it is hoped that this review will permit a better understanding of the relevance of DD as a clinical sign.

How I do it—pineal surgery: supracerebellar infratentorial versus occipital transtentorial

BackgroundResection of a pineal tumour requires fastidious pre-operative planning to select the optimal surgical approach and maximise resection while minimising morbidity.MethodTo describe and compare the supracerebellar infratentorial and occipital transtentorial approaches.ConclusionsSpecific considerations include patient-specific anatomy, extent and relationships of the tumour, and the techniques likely to be employed during resection. The supracerebellar infratentorial approach provides a direct corridor to pineal tumours caudal to the deep veins; for tumours invaginating the tectal plate in a caudal direction the occipital transtentorial provides a better view.

Graph theory analysis of complex brain networks: new concepts in brain mapping applied to neurosurgery

Neuroanatomy has entered a new era, culminating in the search for the connectome, otherwise known as the brains wiring diagram. While this approach has led to landmark discoveries in neuroscience, potential neurosurgical applications and collaborations have been lagging. In this article, the authors describe the ideas and concepts behind the connectome and its analysis with graph theory. Following this they then describe how to form a connectome using resting state functional MRI data as an example. Next they highlight selected insights into healthy brain function that have been derived from connectome analysis and illustrate how studies into normal development, cognitive function, and the effects of synthetic lesioning can be relevant to neurosurgery. Finally, they provide a précis of early applications of the connectome and related techniques to traumatic brain injury, functional neurosurgery, and neurooncology.

Radiofrequency thermocoagulation for trigeminal neuralgia without intra-operative patient waking

Abstract Objective. It is proposed that radiofrequency thermocoagulation (RFT) under general anaesthesia without waking the patient intra-operatively, which is usually performed to confirm lesion location, will reduce the peri-operative discomfort and anxiety suffered by patients. Methods. A retrospective review of all procedures, identified through standard hospital audit codes and performed by a single surgeon from 2000 to 2007. Postal questionnaires were sent to all eligible patients. Outcome criteria included pain relief, adverse events and patients’ views on satisfaction, timing and outcomes. A Kaplan–Meier plot was used to determine actuarial rates of pain relief. Results. Follow-up was available for 84% (37/44) of patients. Complete post-operative pain relief was 96% (42/44). The actuarial rates of complete pain relief at 6, 12, 24 and 36 months were 89%, 79%, 66% and 43%. No patients reported an outcome that did not meet their expectations while 71% (20/28) had an outcome that was better than their expectation. Serious complications included corneal numbness affecting 12% (5/41), but no cases of keratitis and a single case of anaesthesia dolorosa. Conclusions. Not waking a patient intra-operatively when performing a RFT is a viable treatment option that results in excellent early pain relief, comparable to results in the literature and without an increase in complications. Patient reported outcomes indicate a high rate of satisfaction and are a novel addition to our understanding of the procedure; there is no comparable data in the literature documenting patient satisfaction outcomes when the procedure is performed with patient waking.

Muscle and nerve biopsy for the neurosurgical trainee

Abstract Background. Nerve and muscle biopsy are common procedures often performed by junior surgical trainees. This educational review article describes the operative details of performing biopsies of muscle and nerve. Indications, pre-operative investigations and complication rates are described to aid in proper patient selection. Methods. A systematic literature review was performed to identify the indications, surgical techniques and results for nerve and muscle biopsy. Results. The most commonly described techniques involve vastus lateralis muscle, distal sural nerve, median sural nerve/gastrocnemius muscle, superficial peroneal nerve/peroneus brevis muscle and superficial radial nerve. Each technique has its own relative merits and intra-operative anatomical nuances. The yield from each of the techniques varies with the indications and patient selection. Complication rates are low but do vary between the techniques. Conclusions. Judicious use of pre-operative investigations is required to select out patients whose nerve and muscle biopsy justifies the risk of complications. A thorough knowledge of relevant surgical anatomy and correct specimen handling is paramount to achieving optimal results while avoiding complications.

Ophthalmological outcome after resection of tumors based on the pineal gland.

OBJECT Descriptions of visual dysfunction in pineal gland tumors tend to focus on upward gaze palsy alone. The authors aimed to characterize the nature, incidence, and functional significance of ophthalmological dysfunction after resection of tumors based on the pineal gland. METHODS Review of a retrospective case series was performed and included consecutive patients who underwent surgery performed by a consultant neurosurgeon between 2002 and 2011. Only tumors specifically based on the pineal gland were included; tumors encroaching on the pineal gland from other regions were excluded. All patients with visual signs and/or symptoms were reviewed by a specialist consultant neuroophthalmologist to accurately characterize the nature of their deficits. Visual disturbance was defined as visual symptoms caused by a disturbance of ocular motility. RESULTS A total of 20 patients underwent resection of pineal gland tumors. Complete resection was obtained in 85%, and there were no perioperative deaths. Visual disturbance was present in 35% at presentation; of those who had normal ocular motility preoperatively 82% had normal motility postoperatively. In total, 55% of patients had residual visual disturbance postoperatively. Although upward gaze tended to improve, significant functional deficits remained, particularly with regard to complex convergence and accommodation dysfunction. Prisms were used in 25% but were only ever partially effective. Visual outcome was only related to preoperative visual status and tumor volume (multivariate analysis). CONCLUSIONS Long-term visual morbidity after pineal gland tumor resection is common and leads to significant functional impairment. Improvement in deficits rarely occurs spontaneously, and prisms only have limited effectiveness, probably due to the dynamic nature of supranuclear ocular movement coordination.

Boxing sparring complicated by an acute subdural haematoma and brainstem haemorrhage.

Abstract A professional boxer developed an acute subdural haematoma after boxing sparring. Despite timely surgical decompression, he had a poor overall outcome predominantly from a delayed brainstem haematoma. Magnetic resonance imaging (MRI) was used to elucidate the pathophysiology of the patients’ injury and clinical condition.

Advanced magnetic resonance imaging and neuropsychological assessment for detecting brain injury in a prospective cohort of university amateur boxers

Background/aim The safety of amateur and professional boxing is a contentious issue. We hypothesised that advanced magnetic resonance imaging and neuropsychological testing could provide evidence of acute and early brain injury in amateur boxers. Methods We recruited 30 participants from a university amateur boxing club in a prospective cohort study. Magnetic resonance imaging (MRI) and neuropsychological testing was performed at three time points: prior to starting training; within 48 h following a first major competition to detect acute brain injury; and one year follow-up. A single MRI acquisition was made from control participants. Imaging analysis included cortical thickness measurements with Advanced Normalization Tools (ANTS) and FreeSurfer, voxel based morphometry (VBM), and Tract Based Spatial Statistics (TBSS). A computerized battery of neuropsychological tests was performed assessing attention, learning, memory and impulsivity. Results During the study period, one boxer developed seizures controlled with medication while another developed a chronic subdural hematoma requiring neurosurgical drainage. A total of 10 boxers contributed data at to the longitudinal assessment protocol. Reasons for withdrawal were: logistics (10), stopping boxing (7), withdrawal of consent (2), and development of a chronic subdural hematoma (1). No significant changes were detected using VBM, TBSS, cortical thickness measured with FreeSurfer or ANTS, either cross-sectionally at baseline, or longitudinally. Neuropsychological assessment of boxers found attention/concentration improved over time while planning and problem solving ability latency decreased after a bout but recovered after one year. Conclusion While this neuroimaging and neuropsychological assessment protocol could not detect any evidence of brain injury, one boxer developed seizures and another developed a chronic sub-dural haematoma.

Combined intracranial pressure monitoring and cerebrospinal fluid infusion study to guide management of slit ventricle syndrome.

Introduction: Slit ventricle syndrome remains a complex entity presenting a considerable challenge to treat successfully. This study aims to demonstrate the application of dual intracranial pressure (ICP) and infusion studies together with the novel shunt occlusion test in both a diagnostic and therapeutic role. Case Report: An 8-year-old child had aqueduct stenosis treated with a ventriculoperitoneal shunt (medium-pressure valve). The presentation was of headaches with papilloedema. Imaging with both computed tomography and magnetic resonance imaging revealed slit ventricles. Initially a shunt exploration revealed distal obstruction that was treated together with insertion of a paediatric strata II regular valve; however, the child continued to deteriorate. Overnight ICP monitoring revealed dramatically raised ICP with poor compensatory reserve. Intra-operative infusion study revealed a shunt that was patent distally but with proximal obstruction. A subtemporal decompression ipsilateral to the shunt was performed together with adjustment of the paediatric strata II regular valve to 2.5 in order to prevent overdrainage. This led to normalisation of ICP, resolution of papilloedema and symptomatic improvement. Discussion: We demonstrate how combined ICP monitoring and shunt infusion studies can be used to help guide management. Unilateral subtemporal decompressions and preventing shunt overdrainage can result in normalisation of ICP and cerebrospinal fluid dynamics.

Steroids and brain tumors.

Abstract Brain tumors produce a variety of signs and symptoms that are often dramatically relieved by glucocorticosteroids (‘steroids’). Almost all patients with high-grade gliomas or metastatic brain tumors will receive steroids, usually dexamethasone, at some point in their illness. Despite their ubiquity of use, it is still not clear how steroids exert their clinical effect. In this chapter the various mechanisms by which steroids may alter aspects of tumoral and peritumoral brain pathophysiology are discussed. Specific areas discussed include: mechanisms of action on brain tumor parenchyma and peritumoral brain; blood flow and metabolic changes; effects on vasogenic edema; and altering the pathophysiology of peritumoral brain. Finally, a practical guide to the clinical use of steroids is proposed, covering indications, dosing, management of side-effects, and withdrawal of steroids.