Epidural anesthesia

In epidural anaesthesia, the anaesthetist injects one or more drugs into the epidural space bordering on the spinal dura mater to achieve a "central" and/or "neuraxial" block. It is one of the earliest techniques in anaesthesia, originally performed exclusively with local anaesthetic agents. Adding other drugs and combining epidural with general anaesthesia or adapting the technique to the needs of children has extended the list of indications. Continuous epidural analgesia is an important tool in postoperative pain management. More and more often, the increasing proportion of patients who have comorbidities or are permanently taking medication that modulates the clotting system demands that the anaesthesiologist balance the individual risks and benefits before inducing epidural anaesthesia.     

Epidural abscesses

Until recently epidural abscess was considered a rare, almosttheoretical, complication of central nerve block, but anecdotalreports suggest that this is no longer the case. Thus a reviewof the risk factors, pathogenesis, clinical features and outcomeof this condition is appropriate, the primary aim being to makerecommendations on best anaesthetic practice to minimize therisk of this serious complication. A search of EMBASE©,PUBMED© and MEDLINE© databases from 1966 to September2004 was performed using several strategies, supplemented byreference list screening. Spontaneous epidural abscess is rare,accounting for 0.2–1.2 cases per 10 000 hospital admissionsper year. Estimates of the incidence after central nerve blockvary from 1:1000 to 1:100 000. Risk factors (compromised immunity,spinal column disruption, source of infection) are present inthe majority of patients, whether the condition is spontaneousor associated with central nerve block. Presentation is vague,fever and back pain usually preceding neurological deficit.Diagnosis requires a high index of suspicion and modern imagingtechniques. Treatment involves early surgical drainage to preventpermanent deficit and high dose parenteral antibiotics chosenwith bacteriological advice. Primary prevention depends on properuse of full aseptic precautions. Epidural abscess can be a catastrophicconsequence of central nerve block. Early diagnosis will minimizepermanent damage, but primary prevention should be the aim.There is a need for a large survey to indicate the true incidenceto better inform the risk–benefit ratio for central nerveblock.     

Epidural lipomatosis

ONSET: Epidural lipomatosis is a rare disorder defined as a pathological overgrowth of normal epidural fat. It is more often associated with administration of exogenous steroid with variable duration and doses. Furthermore, it may occur in some patients in the absence of exposure to steroids but generally associated with obesity. Whatever the predisposing factor, the majority of these patients are men. The causal effect of epidural lipomatosis in the development of spinal cord or radicular compression is generally well accepted. DIAGNOSIS: The diagnosis of epidural lipomatosis can be established by melography, computed tomography (CT) and magnetic resonance imaging (MRI). MRI is considered the imaging procedure of choice, allowing an assessment of the extent of lipomatosis and, as well as CT, an identification of the lipomatous tissue. Most cases of epidural lipomatosis with corticosteroid use occur in the thoracic region, while most idiopathic cases occur in the lumbar region. TREATMENT: Management of treatment depends on the severity of the neurological signs and the patient's background. The most common treatment for epidural lipomatosis with corticosteroid use consists in surgical decompression but with a high risk of postoperative mortality. In some cases however, medical treatment includes corticosteroid withdrawal or reduction and calorie restriction, leading to clinical improvement. Treatment for idiopathic epidural lipomatosis is more often medical, based on weight loss and physical therapy with generally successful outcome. The pathogenesis of epidural lipomatosis remains unknown but different suggested hypotheses may lead to a metabolic disorder as the underlying cause.     

Epidural haematoma

Editor—We read with interest the recent case report inwhich a patient treated with clopidogrel and dalteparin developedan epidural haematoma following a combined spinal-epidural anaesthetic.¹Although the authors describe the commonly quoted incidenceof spinal haematoma following epidural and spinal anaesthesiabetween 1 in 150 000 and 1 in 220 000, the true incidence isunknown. The Victorian Consultative Council on Anaesthetic Mortalityand Morbidity (VCCAMM) is a system that monitors, analyses andreports on key areas of potentially preventable anaestheticmortality and morbidity within the Victorian hospital systemin Australia.² It has recently reported a number of major complicationsfollowing regional anaesthesia techniques with concerns regarding