Manual In-line Stabilization Increases Pressures Applied by the Laryngoscope Blade during Direct Laryngoscopy and Orotracheal Intubation

2009 ◽  
Vol 110 (1) ◽  
pp. 24-31 ◽  
Author(s):  
Brandon G. Santoni ◽  
Bradley J. Hindman ◽  
Christian M. Puttlitz ◽  
Julie B. Weeks ◽  
Nathaniel Johnson ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Direct Laryngoscopy ◽  
Random Order ◽  
Orotracheal Intubation ◽  
Laryngoscope Blade ◽  
Cervical Instability ◽  
Cervical Spine Instability ◽  
Pressure Application ◽  
Glottic View ◽  
Cervical Motion

Background Manual in-line stabilization (MILS) is recommended during direct laryngoscopy and intubation in patients with known or suspected cervical spine instability. Because MILS impairs glottic visualization, the authors hypothesized that anesthesiologists would apply greater pressure during intubations with MILS than without. Methods Nine anesthetized and pharmacologically paralyzed patients underwent two sequential laryngoscopies and intubations, one with MILS and one without, in random order. A transducer array along a Macintosh 3 laryngoscope blade continuously measured applied pressures, and glottic view was characterized. Results With MILS, glottic visualization was worse in six patients, and intubation failure occurred in two of these six patients. Maximum laryngoscope pressure at best glottic view was greater with MILS than without (717 +/- 339 mmHg vs. 363 +/- 121 mmHg, respectively; n = 8; P = 0.023). Other measures of pressure application also indicated comparable increases with MILS. Conclusion Pressures applied to airway tissues by the laryngoscope blade are secondarily transmitted to the cervical spine and result in cranio-cervical motion. In the presence of cervical instability, impaired glottic visualization and secondary increases in pressure application with MILS have the potential to increase pathologic cranio-cervical motion.

Cervical Spine Motion with Direct Laryngoscopy and Orotracheal Intubation

1996 ◽  
Vol 85 (1) ◽  
pp. 26-36 ◽  
Author(s):  
Paul D. Sawin ◽  
Michael M. Todd ◽  
Vincent C. Traynelis ◽  
Stella B. Farrell ◽  
Antoine Nader ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Direct Laryngoscopy ◽  
Sagittal Plane ◽  
Human Subjects ◽  
Orotracheal Intubation ◽  
Segmental Motion ◽  
Macintosh Blade ◽  
Spine Motion ◽  
Reproducible Method ◽  
Cervical Motion

Background Cervical spine kinetics during airway manipulation are poorly understood. This study was undertaken to quantify the extent and distribution of segmental cervical motion produced by direct laryngoscopy and orotracheal intubation in human subjects without cervical abnormality. Methods Ten patients without clinical or radiographic evidence of cervical spine abnormality underwent laryngoscopy using a #3 Macintosh blade while under general anesthesia and neuromuscular blockade. Cervical motion was recorded with continuous lateral fluoroscopy. The intubation sequence was divided into distinct stages and the corresponding fluoroscopic images were digitized. Segmental motion, occiput through C5, was calculated for each stage using the digitized data. Results During exposure and laryngoscope blade insertion, minimal displacement of the skull base and rostral cervical vertebral bodies was observed. Visualization of the larynx created superior rotation of the occiput and C1 in the sagittal plane, and mild inferior rotation of C3-C5. C2 maintained nearneutral posture. This pattern of displacement resulted in extension at each motion segment, with the most significant motion produced at the occipitoatlantal and atlantoaxial joints (mean = 6.8 degrees and 4.7 degrees, respectively). Intubation created slight additional superior rotation at the occiput and C1, without substantial alteration in the posture of C2-C5. After laryngoscope removal, position trended toward baseline at all levels, although exact neutral posture was not regained. Conclusions This investigation quantifies the behavior of the normal cervical spine during direct laryngoscopy with a Macintosh blade. With this maneuver, the vast majority of cervical motion is produced at the occipitoatlantal and atlantoaxial joints. The subaxial cervical segments (C2-C5) are displaced only minimally. This study establishes a highly reliable and reproducible method for analyzing cervical motion in real time.

scholarly journals Craniocervical Motion during Direct Laryngoscopy and Orotracheal Intubation with the Macintosh and Miller Blades

2007 ◽  
Vol 107 (6) ◽  
pp. 884-891 ◽  
Author(s):  
Scott A. LeGrand ◽  
Bradley J. Hindman ◽  
Franklin Dexter ◽  
Julie B. Weeks ◽  
Michael M. Todd
Keyword(s):  
Direct Laryngoscopy ◽  
Sagittal Plane ◽  
Macintosh Laryngoscope ◽  
Cervical Vertebra ◽  
Random Order ◽  
Orotracheal Intubation ◽  
Mean Difference ◽  
Routine Practice ◽  
Macintosh Blade ◽  
Cervical Motion

Background Previous studies have characterized segmental craniocervical motion that occurs during direct laryngoscopy and intubation with a Macintosh laryngoscope blade. Comparable studies with the Miller blade have not been performed. The aim of this study was to compare maximal segmental craniocervical motion occurring during direct laryngoscopy and orotracheal intubation with Macintosh and Miller blades. Methods Eleven anesthetized and pharmacologically paralyzed patients underwent two sequential orotracheal intubations, one with a Macintosh blade and another with a Miller in random order. During each intubation, segmental craniocervical motion from the occiput to the fifth cervical vertebra (C5) was recorded using continuous lateral cinefluoroscopy. Single-frame images corresponding to the point of maximal cervical motion for both blade types were compared with a preintubation image. Using image analysis software, angular change in the sagittal plane at each of five intervertebral segments was compared between the Macintosh and Miller blades. Results Extension at occiput-C1 was greater with the Macintosh blade compared with the Miller (12.1 degrees +/- 4.9 degrees vs. 9.5 degrees +/- 3.8 degrees, respectively; mean difference = 2.7 degrees +/- 3.0 degrees; P = 0.012). Total craniocervical extension (occiput-C5) was also greater with the Macintosh blade compared with the Miller (28.1 degrees +/- 9.5 degrees vs. 23.2 degrees +/- 8.4 degrees, respectively; mean difference = 4.8 degrees +/- 4.4 degrees; P = 0.008). Conclusions Compared with the Macintosh, the Miller blade was associated with a statistically significant, but quantitatively small, decrease in cervical extension. This difference is likely too small to be important in routine practice.

Mechanical Properties of Injured Human Cervical Spine Ligaments and Corresponding Effect on Spinal Kinematics

2011 ◽  
Author(s):  
P. Devin Leahy ◽  
Christian M. Puttlitz
Keyword(s):  
Cervical Spine ◽  
Soft Tissue ◽  
Dynamic Range ◽  
Traumatic Injury ◽  
Soft Tissue Injuries ◽  
Neurological Impairment ◽  
Cervical Instability ◽  
Cervical Spine Instability ◽  
Tissue Injuries ◽  
Flexion And Extension

The assessment of cervical spine instability following traumatic injury is controversial [1, 4, 5, 8]. Typical definitions of cervical instability are based on the presence of several key detectable injuries using simple radiographs, computed tomography (CT), and magnetic resonance (MR) imaging. Although these imaging modalities have been shown to be relatively reliable for detection of fractures and very large soft tissue injuries, they are largely deficient for determining the presence of smaller soft tissue injuries, such as hyperstrained ligaments [1, 3]. Soft tissue injuries of this nature may be revealed with dynamic range of motion (ROM) assessment, such as a flexion and extension test with radiography. However, these tests are currently inadequate for determining the existence of specific injuries. Cervical soft tissue injuries demand further analysis, given the risk of severe and permanent neurological impairment that may accompany these injuries [2, 5].

Manual In-Line Stabilization Increases Pressure Applied by the Laryngoscope Blade During Direct Laryngoscopy and Orotracheal Intubation

2011 ◽  
Vol 55 (1) ◽  
pp. 54
Author(s):  
Brandon G. Santoni ◽  
Bradley J. Hindman ◽  
Christian M. Puttlitz ◽  
Julie B. Weeks ◽  
Nathaniel Johnson ◽  
...  
Keyword(s):  
Direct Laryngoscopy ◽  
Orotracheal Intubation ◽  
Laryngoscope Blade

Transverse connectors providing increased stability to the cervical spine rod-screw construct: an in vitro human cadaveric study

2011 ◽  
Vol 14 (6) ◽  
pp. 719-725 ◽  
Author(s):  
Miranda N. Shaw ◽  
Etienne P. Morel ◽  
P. Andrew Utter ◽  
Yazeed M. Gussous ◽  
Lise Ginoux ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Range Of Motion ◽  
Random Order ◽  
Axial Rotation ◽  
Cadaveric Study ◽  
Lateral Bending ◽  
Cervical Instability ◽  
Flexion And Extension

Object The object of this study was to determine if the addition of transverse connectors (TCs) to a rod-screw construct leads to increased stabilization of the cervical spine. Methods Eleven human cadaveric cervical spines (C2–T1) were used to examine the effect of adding connectors to a C3–7 rod-screw construct in 3 models of instability: 1) C3–6 wide laminectomy, 2) wide laminectomy and 50% foraminotomy at C4–5 and C5–6, and 3) wide laminectomy with full medial to lateral foraminotomy. Following each destabilization procedure, specimens were tested with no TC, 1 TC between the C-5 screws, and 2 TCs between the C-4 and C-6 screws. Testing of the connectors was conducted in random order. Specimens were subjected to ± 2 Nm of torque in flexion and extension, lateral bending, and axial rotation. Range of motion was determined for each experimental condition. Statistical comparisons were made between the destabilized and intact conditions, and between the addition of TCs and the absence of TCs. Results The progressive destabilization procedures significantly increased motion. The addition of TCs did not significantly change motion in flexion and extension. Lateral bending was significantly decreased with 2 connectors, but not with 1 connector. The greatest effect was on axial rotation. In general, 2 TCs were more restrictive than 1 TC, and decreased motion 10% more than fixation alone. Conclusions Regardless of the degree of cervical destabilization, 1 or 2 TCs decreased motion compared with rods and screws alone. Axial rotation was most affected. Transverse connectors effectively increase the rigidity of rod-screw constructs in the cervical spine. Severe cervical instability can be overcome with the use of 2 TCs, but in cases in which 2 cannot be used, 1 should be adequate and superior to none.

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