Delayed epidural catheter removal: the impact of postoperative coagulopathy.

A retrospective analysis of 413 patients who received postoperative epidural analgesia under a standardized protocol found that 84 (20%) had a duration of epidural catheterization of greater than four days. The most common reasons were significant pain (n=64, 15%) and coagulopathy (n=26, 6%). Risk factor analysis for coagulopathy showed an odds ratio of 10.1 (95% confidence interval 4.2-24.5) for prolonged epidural catheterization among patients undergoing hepatectomy. Magnetic resonance imaging, performed in four patients with clinical signs suggestive of epidural haematoma, was negative for a space-occupying lesion in all cases. Eleven patients developed fever and clinical signs suggestive of epidural catheter-related infection, necessitating early catheter removal. Sixteen patients had persistent lower limb weakness at 24 hours after catheter removal. The signs soon resolved in all except two, one of whom had neuropathy related to intraoperative positioning and the other preoperative weakness. Accidental epidural catheter dislodgement occurred in 29 patients (7%) and is potentially hazardous if coagulopathy is unresolved. The risk-benefit ratio and factors complicating catheter removal, especially coagulopathy, should be considered when deciding whether to use epidural techniques.

Neurolytic celiac plexus block for visceral abdominal malignancy: is prior diagnostic block warranted?

Neurolytic celiac plexus block is a recognised treatment for visceral abdominal pain due to malignancy. The need for a diagnostic celiac plexus block prior to neurolytic blockade is of questionable value, as it may not predict a positive response and may incorrectly predict a lack of response. Our objective is to evaluate the efficacy of diagnostic celiac plexus block. The records of 59 patients treated with celiac plexus block during 1994-2000 were retrospectively reviewed. Diagnostic block was performed on 32 patients prior to the decision for subsequent neurolytic block (Group 1). Another 27 patients were directly treated with a neurolytic celiac plexus block (Group 2). Response of Group 1 to diagnostic and neurolytic blocks was compared. Data from Group 2 was used to project the response of Group 1 should those patients with negative response to diagnostic block proceeded to neurolytic block. A two-by-two table was then constructed. The diagnostic celiac plexus block predicted a positive response with a sensitivity of 93% and a specificity of 37%. The positive predictive value was 85% and the negative predictive value was 58%. The estimated "number needed to test" before a "true" nonrespondent to lytic block to be detected was 16.7. Therefore, a positive response to diagnostic block correlates positively with neurolytic celiac plexus block for abdominal visceral pain due to malignancy. However, diagnostic block is a poor predictor when the response is negative. Hence, its clinical role is questionable and may not be warranted for patients with terminal malignancy.

Spinal haematoma following epidural anaesthesia in a patient with eclampsia.

A patient with a twin pregnancy required a Caesarean section for severe pre-eclampsia. Her platelet count was 71 x 10(9).l-1. Epidural anaesthesia was performed after platelet transfusion. A spinal epidural haematoma was diagnosed postoperatively. A generalised tonic-clonic seizure sparing the lower limbs enabled early diagnosis to be made. The patient recovered with no permanent neurological damage after laminectomy and clot removal. The risks and benefits of regional techniques require careful consideration, and postoperative monitoring for recovery of neural blockade is essential.

Display and visualization of three-dimensional reconstructed anatomic morphology: experience with the thorax, heart, and coronary vasculature of dogs.

A new method, termed reprojection, is used to visualize anatomic morphology contained within three-dimensional reconstructions made up of images of multiple parallel cross sections. This method involves the projection, either orthographically into a plane or radially onto a cylinder, of the volume picture elements (voxels) of the reconstruction. Orthographic reprojection images, formed by mathematically summing the magnitudes of the voxels along selected parallel paths through the reconstructed volume, are analagous to conventional radiographs formed by the passage of an X-ray beam through the volume. The reprojection image is a two-dimensional array of picture elements that is displayed on a television monitor using a digital-to-video scan converter. Also described are the techniques of noninvasive selective tissue dissolution and numerical dissection, whereby obscuring portions of the reconstructed volume are either partially "dissolved" or totally eliminated before reprojection. Utilizing these methods, anatomic information present in a three-dimensional reconstruction but not clearly seen in a reprojection image is rendered visible after removal of superposed structures. The usefulness of these methods is demonstrated utilizing three-dimensional reconstructions of the thorax, heart, and coronary arteries of dogs.