A comparison of the effects of conventional and balloon laryngoscopy on the sagittal dimensions of the space available for the cord at the level of the occipitoatlantoaxial complex
KeywordsCatheter Full Text Anatomic Landmark Cervical Vertebra Foley Catheter
The purpose of this study was to compare the sagittal surface areas (SSAs) of the space available for the cord (SAC) at the occiput (OCC)-first cervical vertebra (C1) and C1-C2 levels determined at neutral head position, and during conventional and balloon laryngoscopy [1,2].
Anesthesia was induced in eight ASA I, Mallampati I, elective surgery patients. Cross-table lateral-view radiographs were taken at neutral head position (NHP) and upon maximal laryngeal exposure (MLE) with a #4 standard and a #4 modified blade carrying two 10 Foley catheters. MLE during balloon laryngoscopy was achieved by right catheter-balloon inflation with 2 ml air and blade-elevation [1,2]. The radiographs were scanned in Photoshop 5.0, the X-ray magnification was determined, and the OCC-C1 and C1-C2 SAC-SSAs were measured with Autocad 2000. The OCC-C1-SAC and C1-C2-SAC anatomic landmarks are shown in Fig.1. Data were analyzed with Kolmogorov-Smirnov test and ANOVA.
At the OCC-C1 level, the SAC-SSA was significantly reduced during conventional laryngoscopy (MLE-value =0.386± 0.104 in2, NHP-value =0.501± 0.11 in2, P=0.0095). During balloon laryngoscopy, there was no significant SAC-SSA reduction (MLE-value =0.423± 0.128 in2, P=0.07 vs NHP-value), while the SAC-SSA was significantly greater than the SAC-SSA determined during conventional laryngoscopy (P=0.044). At the C1-C2 level, the SAC-SSA-changes were nonsignificant.