Epidural steroid injection is a safe outpatient procedure, which is performed best using image guidance in conjunction with epidurography. Using the techniques described earlier, complications are minimized, and serious complications can be avoided, in experienced hands. The author has performed several thousand procedures in an outpatient setting without any serious complications. Optimal safety and efficacy require an excellent working knowledge of the radiographic anatomy, and the imaging equipment used to perform these procedures. Several studies have demonstrated the difficulty and uncertainty of obtaining an accurate injection without imaging guidance. Radiologists who are well trained in the performance of image-guided percutaneous injection procedures are thus armed with the background to perform these procedures in a safe and efficacious manner. In addition, referral of these procedures to a third party (radiologist) without economic incentives reduces the potential abuse of self-referral--which may occur (or be suspected by payors) when the primary clinician recommends, and then performs, pain management procedures. The use of sedation to perform these procedures is unnecessary, and deep sedation may be dangerous when injections are performed in the vicinity of the spinal cord. The author's experience, which includes clinical feedback and formal trials, shows the technique described in this article to be performed safely without sedation in an outpatient setting, with a high success rate for alleviating pain symptoms. When properly performed, epidural steroid injections have a clinically established role in the management of neck and back pain.

Anesthetics, Local↗

PubMed1999

Multidimensional chemotopic responses to n-aliphatic acid odorants in the rat olfactory bulb.

In an effort to understand the means by which similar chemical odorants are encoded in the mammalian brain, we exposed rats to a homologous series of n-aliphatic acids and mapped the response of the entire olfactory bulb glomerular layer by using a high-resolution [14C]-2-deoxyglucose uptake technique. We found that these similar odorants evoked spatially clustered but distinct responses in the bulb that changed systematically with carbon chain length. In addition to these chemotopic responses, different odorants within the series evoked systematic differences along two other dimensions: amount of deoxyglucose uptake and extent of the glomerular layer showing high activity. Increases along these two dimensions also were correlated with increasing carbon number. The focal glomerular responses were mirrored by responses in deeper bulb layers. Decreasing the odorant concentration decreased the deoxyglucose uptake within focal regions. The focal regions of activity occurred in pairs involving both medial and lateral representations in the bulb, perhaps reflecting the paired medial and lateral projections of olfactory sensory neurons expressing specific types of odorant feature receptor proteins. The observed spatial pattern of response also may explain both the failure of some bulb lesions to interfere with behavioral olfactory responses and the success of other lesions in blocking olfactory responses. These data support a model of parallel, distributed processing of odorants along multiple dimensions. They also support the notion that analyses of the spatial relationships among odorant responses in the olfactory bulb can demonstrate aspects of the mechanism for odor chemical coding.

Animals↗