Εναλλακτικές προσπελάσεις με τη βοήθεια υπερήχων του παρασπονδυλικού χώρου και κλάδων του οσφυϊο-ιερού πλέγματος για αναισθησιολογικές χρήσεις

Abstract

Method For this study, a series of adult human formalin-embalmed cadavers was used. The study was performed in the dissection room of the Anatomy Department at the Medical School of the University of Athens (Athens, Greece). All cadavers were donators and did not have any pathology in the thoracic wall. Each cadaver was placed in the prone position, and specific thoracic levels were identified by palpation of the scapula and the intercostals spaces. In embalmed cadavers the production of gas in tissues generates variable artifacts that limit ultrasound examination. For this reason, an anesthesiologist with clinical experience in ultrasound-guided techniques assessed the ability to obtain an acceptable sonographic image of the posterior area of the trunk between the level of the fifth and seventh thoracic (Th) vertebrae. A portable ultrasound machine (MicroMaxx, SonoSite Inc., Bothel, WA, USA; L38e 10-5 MHz broadband linear array) was used to identify specific anatomic structures (spinous and transverse process, ribs, external intercostal muscle and pleura) in each cadaver In case the imaging quality of the examined tissues was poor at an extended area of the trunk of a cadaver, then that particular cadaver was excluded from the study. Cadavers with artifacts limited to a small number of intercostal spaces were enrolled, excluding the particular unacceptable spaces. For all enrolled cadavers, randomization by coin toss determined the side of the body on which all intercostal injections were performed with the first technique, denoted as the transverse technique; at the opposite side all the injections were made with the second technique, denoted as the longitudinal technique. The level of the examined intercostal spaces was from Th 5 to Th 7. On each side, when the Th 5 and Th 7 spaces were acceptable, they were both used for the same technique. In all other cases, a single injection was made to the intercostal space that presented the best sonographic image among Th 5, Th 6, and Th 7 spaces of the same side and using the selected technique for that particular side. For the transverse technique, the probe was placed transversely near the midline, and the spinous process, the lamina and the transverse process were recognized with their typical acoustic shadow. The probe was then moved laterally and slightly obliquely, heading slightly caudal and following the course of the rib. More laterally, the rib was visualized at a small depth from the skin surface. As the probe slid caudally, the rib disappeared and the pleura was depicted at a deeper level as a hyperechoic structure. The aim was to obtain a sonographic view exactly below the inferior margin of the rib, a region adjacent to the intercostal groove. At this site, the lateral part of the pleura appears parallel to the skin surface while the medial part curves into the mediastinum. An 18-gauge Tuohy needle (EpiLong I, Pajunk, Germany) was inserted using the in-plane approach. ................