Functional neurosurgery

It is a great honour to write the editorial for this month’s CMEcomponent of the SAMJ. Functional neurosurgery is a subdivision ofneurosurgery that does not always receive the recognition we feel thatit deserves among general medical practitioners. It is definitely theless ‘sexy’ component of neurosurgery compared with vascular andskull base neurosurgery, but it is an important and highly specialisedpart of our field. There are currently only one academic unit andabout five private sector units that perform functional neurosurgeryprocedures on a regular basis in South Africa. This, unfortunately,leads to many patients and their medical caregivers not knowingabout the options available to them on their doorstep. Patients do notneed to leave the country to search for help in other countries

Remote sensing in Michigan for land resource management: Waterfowl habitat management at Pointe Mouillee

For many years the Pointe Mouillee State Game Area, located on the Lake Erie shoreline just south of Detroit, has been a prime waterfowl habitat. The usefulness of the site for this purpose has been impaired because of the gradual deterioration of the marshland and severe flooding and storms during the spring of 1973. Also, it has been proposed that a dredge spoils area be located in or near the marsh. To aid the future management of a diked refuge area of 148 hectares within the State Game Area, a detailed vegetation inventory was prepared by photointerpretation and a generalized vegetation inventory was obtained by processing multispectral scanner imagery. Also, an analysis was conducted to determine the magnitude of past losses of marshland and the possibilities of replacing this lost habitat. The analysis indicated that large additions to waterfowl habitat could be provided by changes in management of vegetation in existing sections of the State Game Area, through acquisition and conversion of adjacent land by the Michigan Department of Natural Resources, and by the proposed construction of a barrier dike offshore of Pointe Mouillee. Altogether, the various measures considered in this report could affect a total area of nearly 13 sq. km

Surgical management of movement disorders

Movement disorders are usually treated by neurologists, and appropriately so. The first-line management of all conditions that are groupedtogether as movement disorders (e.g. Parkinson’s disease, dystonia, essential tremor) is with medication and, in some, with rehabilitativestrategies, such as occupational therapy, physiotherapy and even psychotherapy. In general, if these strategies fail or have undesirableconsequences, surgery would become an option. Intramuscular injection of botulinum toxin is also very useful in the focal dystonias, such aswriter’s cramp, and in the occupation-specific dystonias, such as musician’s dystonia or hairdresser’s dystonia. The limiting factor is the totalsafe dosage allowed. One cannot inject every muscle involved in all four limbs in a patient with generalised dystonia. This has led to surgerybeing offered as therapy in certain cases where there have previously not been any alternatives. Surgery does not offer curative procedures formovement disorders, but long-term control with medication is possible, often with significant reduction or complete cessation of symptoms

Surgical management of pain

Severe and intractable pain is one of the most difficult and challenging neurological conditions to deal with and to treat. The entity is notentirely well understood, and the afflicted patients often have significant concomitant neuropsychological problems that obscure the physicalissue at hand. Physicians also do not fully understand what pain is. In a sense all pain is neural in origin. From a therapeutic perspective,pain is divided into visceral (dull and poorly localised owing to enteric sensory receptors) and somatosensory (more discreet and localised– often owing to nociceptors being stimulated) pain. It is detected by nociceptors, i.e. sensory reseptors with the ability to interpret andtransmit noxious stimuli. Treatment options include medication, physical therapy and psychotherapy. The availability of sophisticated newmedication, such as pregabalin, augments the medical arm of therapy. If these therapies fail, and with a thorough multidisciplinary approachinvolving carefully screened cases, surgery may form part of the management. Generally, surgical pain management is divided into neuromodulative(enhancing physiological control of the pain system) and neurodestructive (lesioning and destroying the defined pain generatorin the central nervous system) surgery. Complex pain management should not focus on cure as the only outcome. Patients often experiencepain for years before considering surgery; it would therefore be unwise to expect an immediate cure. Careful psychological support andevaluation is of the utmost importance. This article gives an overview of the neurosurgical management of pain

Surgical management of spasticity

The management of patients with cerebral palsy and other causes of spasticity is a challenge to an entire rehabilitation team and to caregivers.InSouth Africa, neurosurgeons have had limited involvement in this field owing to a perceived lack of options, leaving the care of these patientslargely in the hands of paediatric neurologists and orthopaedic surgeons. A committed team-based approach, where a neurosurgeon is partof the decision-making process, can however significantly improve functional outcomes in patients with spasticity. Key to the evaluationand therapeutic decision-making is the focus on function – not only the range of movement or the presence of spasticity. Some techniquescan completely remove spasticity and contractures, but these mostly leave a patient with more functional impairment than they had beforethe surgery. With the careful combination of botulinum toxin injections and oral baclofen, these patients, who may benefit from furtherorthopaedic and neurosurgical procedures, can be identified and helped in reducing the function-limiting spasticity. With the emphasison function as an individualising factor, significant improvements may follow minor interventions, e.g. performing a surgical procedure toallow reduced hip adductor spasticity, thereby allowing improved hygiene and less pain in a child in whom it was previously not possibleto abduct the hips enough to change a nappy. Functional improvement does not necessarily equate to walking. We describe the process ofevaluating patients with spasticity and outline the surgical decision-making process that helps towards an individualised therapeutic strategyin managing this challenging group of patients

Surgical management of epilepsy

The fact that epilepsy can be cured or ameliorated with surgery is an often neglected and overlooked aspect of modern management.Epilepsy affects almost 50 million people worldwide. One-third of people who suffer from epilepsy are refractory to medication alone. Itis this group of patients who may benefit from epilepsy surgery, which can be divided into three main categories, i.e. resection procedures,disconnection procedures, and neuromodulation procedures. The goal of surgery in epilepsy is to remove the epileptogenic region from thebrain, or to disconnect it and thereby prevent spread to other parts of the brain. In cases where this is not possible owing to the location ofthe epileptic focus, certain neuromodulation techniques may benefit the patient. Successful outcomes of epilepsy surgery techniques varyfrom 50% to 80% in rendering patients free of their epilepsy; many more patients can expect improvement in the severity or frequency oftheir disabling seizures. The outcome depends on factors such as age, location of the epileptogenic zone, histology and cause of the seizures.Patients undergo a detailed and prolonged work-up to determine candidacy and to decide on the safest technique that will lead to the bestoutcomes. An experienced team should perform the surgery. This team should consist of multiple members who can attend to the medical,social, psychological and reintegration needs of the patient before and after surgery

An investigation into the changing relationship between the gold price and South African gold mining industry returns

Background: It is accepted that the gold price impacts on the value of gold mining companies. Previous studies have shown that, in financial crises, gold is considered a ‘safe haven’ investment in developed markets.   Aim: The aim of the study is to investigate whether an investment in gold mining stocks do provide gold price-linked safe haven benefits to investors in an emerging economy. An understanding of the possible safe haven benefits of their companies’ stocks and the variables that influence these benefits would be valuable to managers of gold companies when endeavouring to maximise shareholders’ wealth through hedging and investment decisions.   Methods: Regression analysis is applied to investigate the relationship between gold mining returns, the gold price and the rand–dollar exchange rate within a multifactor model motivated by the arbitrage pricing theory.   Results: The results indicate that there is a strong, yet changing, relationship between the gold price, the rand–dollar exchange rate and gold mining returns.   Conclusion: This study extends the understanding of the changing South African gold mining industry in a world that is still recovering from the global financial crisis

Optimal control of a multilevel DC-link converter photovoltaic system for maximum power generation

This paper describes a new algorithm for optimal control of a PV system under partial shading. A multilevel DC-link is the essential part of the proposed system and its control engages a voltage-hold perturbation and observation (VH-P&O) method combined with a PWM algorithm with permutation of PV sources. The algorithm enables achieving the maximum power generation for any number of PV and converter modules. The main features of the control are: (i) a continual operation of all PV sources, shaded and non-shaded, at their maximum power points, (ii) delivery of all extracted power from PV sources to the load and (iii) generation of multilevel output voltage waveform with a low total harmonic distortion