الفهرس 
Anatomical considerations unique to Neuraxial blocksOnly 14 pages are availabe for public view
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Abstract
Summary
Neuraxial blocks are no longer in a pioneering phase. It is now a well-established technique of anesthesia, and its use has increased significantly during the last 25 years, not only in relation with the increased number of surgical procedures but also as increased proportion of anesthetic procedures.
In contrast with this increased use, which suggests an increased safety of these techniques, data from large scale surveys do not yet show a decrease in the overall rate of complications. Complications and associated injuries will continue to occur as there are many factors to be considered, some of them depend on conditions not related to medical care; however, it is essential that the anesthesiologist has a role in the postoperative care when any incident, complication or adverse event occurs, that he reports it and practices an effective follow up to improve the patient‘s recovery.
Major complications after neuraxial techniques are rare, but can be devastating to the patient and the anesthesiologist. Prevention and management begin during the preoperative visit with a careful evaluation of the patient‘s medical history and appropriate preoperative discussion of the risks and benefits of the available anesthetic techniques. Alternative anesthetic techniques
should be considered for patients at increased risk of neurologic complications following neuraxial block.
The decision to perform a regional anesthetic technique on an anesthetized patient must be made with care, since these patients are unable to report pain on needle placement or injection of local anesthetic. Efforts should also be made to decrease neural injury in the operating room through careful patient positioning.
Recognition of the risk associated with spinal and epidural blockade and anticoagulation, continued surveillance, evaluation of the current information and education are all crucial to averting future causes of spinal hematoma. The patient‘s coagulation status should be optimized at the time of neuraxial block and the level of coagulation must be carefully monitored during the period of epidural catheterization. Indwelling catheters should not be removed in the presence of therapeutic anticoagulation, as this significantly increases the risk of spinal hematoma.
Although infectious complications are rarely associated with neuraxial blocks, they can range from minor colonization of the indwelling devices to major medical emergencies associated with meningitis or epidural abscess. Although the need for a full aseptic technique might seem self-evident, this does not mean that it is always used even though current professional advice advocates it quite definitively.
Postoperatively, patients must be followed closely to detect potential treatable causes and sources of neurologic injury, including expanding spinal hematoma or epidural abscess, constrictive dressings, improperly applied casts and increased pressure on neurologically vulnerable sites.
New neurologic deficits should be evaluated promptly by a neurologist or neurosurgeon to document formally patients evolving neurologic status, arrange further testing or intervention and provide long-term follow up.
Ultrasound guided CNB is a promising alternative to traditional landmark-based techniques. It is noninvasive, safe, simple to use, can be quickly performed, does not involve exposure to radiation, provides real-time images, and is free from adverse effects. Experienced sonographers are able to visualize neuraxial structures with satisfactory clarity using US, and the understanding of spinal sonoanatomy continues to be clarified.
Use of Ultrasound also improves the success rate of epidural access on the first attempt, reduces the number of puncture attempts or the need to puncture multiple levels, and improves patient comfort during the procedure. US guidance also may allow the use of CNB in patients who in the past may have been considered unsuitable for such procedures due to abnormal spinal anatomy.
Ultrasound technology continues to improve and as more anesthesiologists embrace it and acquire the skills necessary to perform US-guided interventions, US-guided CNB may become the standard of care in the future.