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. 2005 Jul-Sep;40(3):162–168.

A Comparison of Head Movement During Back Boarding by Motorized Spine-Board and Log-Roll Techniques

Erik E Swartz *, Jennifer Nowak †, Chandra Shirley ‡, Laura C Decoster †
PMCID: PMC1250254  PMID: 16284635

Abstract

Context: In a patient with a potential cervical spine injury, minimizing or eliminating movement at the head and neck during stabilization and transport is paramount because movement can exacerbate the condition. Any equipment or technique creating less movement will allow for a more effective and safe stabilization of an injured patient, reducing the likelihood of movement and potential secondary injury.

Objective: To compare the amount of head movement created during the log-roll and motorized spine-board (MSB) stabilization techniques.

Design: A 2-condition, repeated-measures design.

Setting: Laboratory.

Patients or Other Participants: Thirteen certified athletic trainers, emergency first responders, and emergency medical technicians (6 men, 7 women).

Intervention(s): Subjects rotated through 4 positions for the log roll and 2 positions for the MSB. Each subject performed 3 trials while maintaining manual, inline stabilization of the model's head for each condition.

Main Outcome Measure(s): Three-dimensional head movement was measured and expressed as degrees of motion.

Results: The log roll created significantly more motion in the frontal and transverse planes compared with the MSB (P = .001 for both measures). No significant difference was noted for sagittal-plane motion (P = .028).

Conclusions: The MSB created less movement at the head than did the log roll in 2 planes of motion and created slightly more motion in 1 plane, although this difference was not significant. The MSB may provide emergency responders with an appropriate alternative method for stabilizing and transporting a supine injured athlete without requiring a log roll.

Keywords: stabilization, cervical spine injury, emergency management

Placing an injured individual with a head, spine, or other serious injury on a spine board is an important skill in emergency medicine. Minimizing or eliminating movement created at the head or spine during the management of a cervical spine injury is paramount because movement can exacerbate the patient's condition.1–3 Unfortunately, because of the unique nature of individual injuries, an acceptable amount of movement cannot be predicted in the field, quantified through research, or generalized from other cases. Therefore, minimizing the amount of movement produced at the head and neck during the spine-boarding task is a critical factor in the successful stabilization, protection, and transportation of a seriously injured person. Any equipment or technique creating less movement will allow for a more effective and safe stabilization of a victim, reducing the likelihood of movement and potential secondary injury.4

Currently, emergency medical technicians, paramedics, certified athletic trainers, and emergency department personnel typically perform a log roll onto a traditional spine board to stabilize and prepare a victim for transportation.5–10 Although research regarding the movement created in the cervical spine during certain management techniques, such as orotracheal intubation11–13 and cervical collar application,4,14,15 is well established, limited research has been performed to document the amount of movement created during placement on a spine board.16–20 One recent group analyzed and compared the techniques of the log roll with the lift and slide by assessing movement created in destabilized cervical spines of cadavers.17 The researchers noted that both techniques created movement at the injured level of the cervical spine, but they found that the lift and slide was more effective in restricting motion at the head than was the log roll. The researchers concluded, however, that neither technique was clearly superior to the other.17

A new type of stabilization technique is now available to emergency responders and athletic trainers: a motorized spine board (MSB). This battery-powered, wedge-shaped device “crawls” under a supine victim by using a dual-action belt system. This technology may minimize head and neck movement of a supine, spine-injured patient during the back-boarding procedure by eliminating the need to perform a log roll. To our knowledge, head or neck movement associated with the use of this recently created device has not been investigated. Therefore, our purpose was to compare head movement created with an MSB and a traditional log-roll spine-boarding technique. Our hypothesis was that the use of the MSB would create less movement at the head than would a log-roll spine-boarding technique onto a standard long board.

METHODS

Subjects

A sample of convenience among subjects with training in spine boarding and current certification in an emergency response profession was used for the study. Thirteen subjects (6 men, 7 women) from the local population participated (6 certified athletic trainers, 4 senior-level athletic training students certified as first responders, and 3 emergency medical technicians) in the log-roll group, and 12 of those subjects participated in the MSB group. Subjects had an average of 4.0 ± 5.30 years (range, 0.5–19) of certified experience in their respective fields and were 27.23 ± 8.75 years of age. Subjects were excluded if they had medical problems prohibiting them from performing the task, such as problems preventing them from lifting or kneeling for an extended period.

Instrumentation

Motion Analysis

A 6-camera, EVa, high-resolution, 3-dimensional kinematic motion-capture system (model 60–240 Falcon; Motion Analysis Inc, Santa Rosa, CA) with a sampling rate of 120 Hz was used to collect the movement data for this investigation. With a conventional x-y-z laboratory coordinate configuration (where x represents anterior and posterior, y represents medial and lateral, and z represents vertical), the motion-capture system tracks the 3-dimensional movement of retroreflective markers in a calibrated volume. The 6 cameras were strategically placed to surround a 3- × 7- × 3-m motion-capture volume in order to decrease the likelihood of markers being obscured from view during data collection. One camera was positioned directly above the volume, and the other 5 were positioned at downward angles at regular intervals above and around the volume. Before each data-collection session, the volume was calibrated by a cube-and-wand calibration technique. After such calibration techniques, marker-error measurement in the Motion Analysis Inc system has been determined to be less than 0.5 mm.21 Kinematic data were smoothed with a fourth-order (2-pass), Butterworth low-pass filter (cutoff = 5 Hz). The EVa 6.06 software was used to measure the movement produced during the task.

Testing Protocol

Subjects reported to the Applied Biomechanics Laboratory of the university for data collection. Each subject signed an informed consent, approved by the university's institutional review board, and received an explanation of the study. Exact instructions were given to all subjects concerning the tasks to be performed, followed by a demonstration on the use of the MSB. During data collection, condition order and subject position rotated according to a computer-generated, latin squares randomization assignment. The four positions were head (S1), upper body (S2), lower body (S3), and board (S4). Before data collection, subjects were required to practice and become comfortable with the techniques and procedures. Although subjects were familiar with the log-roll technique, they were still required to practice the maneuver in their group from each designated position at least twice. Each subject practiced operating the MSB from each of the 2 positions 1 to 2 times, which was sufficient because of its simple operation. The researchers offered no encouragement or assistance during the trials. A research assistant acted as the victim throughout data collection. She was appropriately fitted with a cervical collar before data collection and lay supine in the motion-capture volume.

Six retroreflective markers (2-cm diameter) were strategically placed on the victim: forehead (8-cm length wand marker), left zygomatic bone (3-cm length marker), bite-stick wand (8-cm length wand marker) protruding from the mouth,22 manubrium (8-cm length wand marker), lesser tubercle of the humerus (3-cm length marker), and xiphoid process (8-cm length wand marker) (Figure 1). Marker linkages were then created to provide 4 segments representing the local coordinate system: vertical head, horizontal head, vertical chest, and horizontal chest. These segments were necessary to create the reference angles for the 3-dimensional analysis. The following 3-segment comparisons of the local coordinate system, aligned with the laboratory coordinate system by the right-hand rule technique, were incorporated into an included-angle analysis in the EVa software to provide the head movement data: (1) vertical head and vertical chest: sagittal plane (flexion-extension), (2) horizontal chest and vertical head: frontal plane (right and left lateral flexion), and (3) horizontal chest and horizontal head: transverse plane (right and left rotation) (Figure 2).23

Figure 1. Marker set.

Figure 1

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Figure 2. Segments and included angles.

Figure 2

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A, Sagittal (flexion/extension): VH and VC. B, Frontal (lateral flexion): VH and HC. C, Transverse (rotation): HC and HH. VH indicates vertical head; HH, horizontal head; VC, vertical chest; and HC, horizontal chest

During piloting, motion associated with breathing was assessed at the xiphoid marker. To determine the effect of this motion, the victim was asked to hold her breath for 30 seconds of data collection, and this movement was compared with a 30-second trial with breathing. We found an increase of only 1° in total movement, in the sagittal plane, over the entire 30 seconds. We deemed this amount of movement insignificant. Movement associated with breathing did not create movement in the other planes. Furthermore, minimum and maximum values were the only values to be analyzed to create an absolute degree of change; therefore, this difference would not affect the variable of interest for the purpose of this study.

Spine Boards

The MSB used in this investigation (Vision LLC, Hugo, MN) is unique in that the board is designed to crawl under the victim by using a dual-action belt system, eliminating the need to log roll or lift the victim onto the board (Figure 3). The board is 180.34 cm long, 45.72 cm wide, 1.27 cm high at the front end, and 12.7 cm high at the back end, with a mass of 29.48 kg (65 pounds). It uses a switch powered from a rechargeable battery to initiate forward or backward movement and slowly accelerates from rest to a top speed of 4.5 cm/s (unweighted). The traditional spine board used in this study was a molded plastic 182.88-cm board (HDx Backboard; Life Support Products, Irvine, CA).

Figure 3. Motorized spine board.

Figure 3

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Before performing each trial, subjects were instructed that it was important to create little or no movement at the head. Each subject performed 3 trials as S1 for each of the 2 conditions. Data collection began with the involved subjects appropriately positioned relative to the victim. Subjects did not place their hands on the victim until cued by an audio signal from the video system indicating the start of data collection. After the cue, S1 then directed the other subjects in completing the task. Data collection ended with S1 saying “finished” when the victim was completely loaded on the board. In neither condition did subjects secure the victim to the board.

Log-Roll Condition

The S1 was positioned prone to avoid blocking the camera's view of the head markers (Figure 4) and stabilized the head with both hands. The S2 placed 1 hand on the victim's shoulder (below the shoulder marker) and the other on the victim's hip at the greater trochanter, the S3 placed 1 hand on the victim's ankle or lower leg and the other on the victim's hip at the iliac crest, and the S4 placed the board under and centered to the victim's back once the victim was perpendicular to the floor surface. As well as saying “finished,” commands given by the S1 during the log roll included “1, 2, 3, up” to coordinate the rolling of the victim onto her side and “1, 2, 3, down” when the board was centered and the victim was ready to be rolled down onto the board.

Figure 4. Log rolling a victim onto a back board.

Figure 4

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A, Starting position. B, Up phase. C, Completing the down phase

Motorized Spine-Board Condition

The S1 provided inline stabilization to the head while kneeling to the side of the victim; this was to avoid impeding the MSB as it moved under the victim (Figure 5). For this condition, the S2 and S3 were not necessary. The S4 operated the MSB according to the commands of the S1. The S1 directed the S4 on precisely when to start and then stop movement of the board while observing the victim's position on the board. The completed position was achieved when the victim's head reached a premarked position at the head of the MSB, consistent for all trials.

Figure 5. Loading of a victim onto the motorized spine board.

Figure 5

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A, Starting position. B, Loading. C, Loading complete

After all trials were completed, we tracked and reduced the 3-dimensional data. Data from the 3 trials performed by each subject for the 2 conditions were then exported into spreadsheet format for calculation of means and preparation for statistical analysis.

Statistical Analysis

Our independent variable was spine-board condition (log roll versus MSB), and our dependent variable was absolute change in motion at the head (sagittal, frontal, and transverse planes). Data were analyzed by separate, independent-samples t tests with a confidence level set a priori at 95%, then adjusted by the Bonferroni correction for multiple comparisons, yielding an alpha level of .0167. We used the SPSS statistical software package (version 12.0; SPSS Inc, Chicago, IL) to analyze the data.

RESULTS

Resultant means, SDs, and coefficients of variance for transverse, frontal, and sagittal movement for both the log-roll and MSB conditions are provided in Table 1. The log roll created significantly more motion in the frontal (t23 = −5.90, P = .001) and transverse (t23 = −4.18, P = .001) planes than did the MSB. No significant difference was noted in sagittal-plane motion (t23 = 2.354, P = .028). Table 2 provides the average angle, SD, maximum angle, and minimum angle for both conditions.

Table 1. Mean, SD, and Coefficient of Variance for Head Motion in 3 Planes.

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Table 2. Directional Mean, SD, and Maximal and Minimal Angles for Each Plane (°).

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DISCUSSION

Our results appear to favor the use of the MSB because it allowed for spine boarding a simulated victim with less movement than did the traditional log roll in 2 planes of motion and was comparable in the third plane. The log roll demonstrated more movement in lateral flexion (frontal plane, 9.64 ± 1.91°) and rotation (transverse plane, 9.62 ± 2.68°) than did the MSB (5.96 ± 1.05° and 5.97 ± 1.70°, respectively) by approximately 4° in each case, whereas in flexion-extension (sagittal plane) the MSB (11.21 ± 1.24°) created only approximately 2° more movement than did the log roll (9.64 ± 2.56°).

A potential advantage of the log roll is that the body is theoretically rolled as 1 part, maintaining inline stabilization throughout the process, whereas the MSB requires movement into flexion as the head is “picked up” because of the 0.25-in (0.635-cm) roller at the front of the board. However, a closer look at the results reveals that the log roll had a higher SD (or trial-to-trial variability) than did the MSB in each plane. Furthermore, the coefficient of variation in the log roll for motion in the frontal and sagittal planes was higher than for the MSB. Both techniques demonstrated a high coefficient of variation in the transverse plane, suggesting either a greater overall degree of variability in being able to control motion in this plane from trial to trial or a decreased consistency of the motion-capture set-up in producing consistent measures for this plane. Overall, the increased variability observed in the results for the log roll is likely because of multiple people being involved in the task, thereby making the uniformity of the movement more challenging and, hence, more unpredictable. In contrast, the MSB is more consistent from trial to trial in the amount of movement produced in each plane, and this motion can be expected to primarily occur in the sagittal plane. Therefore, a potential advantage to the MSB is that it is extremely consistent from one trial to the next (ie, has a lower variance).

Our results for the log roll are comparable with those of recent researchers who investigated the amount of head movement produced during the log roll and a 5-person lift-and-slide technique.17 The lift-and-slide technique involves lifting the supine victim high enough to allow another rescuer to slide a backboard underneath and then lowering the victim back down onto the board for stabilization. The researchers analyzed 3-dimensional head movement and also compared the maximal range of movement in each of the 3 planes between the 2 techniques. They found that subjects produced 9.49° of flexion-extension, 12.22° of lateral flexion, and 24.68° of rotation during the log-roll maneuver. The flexion-extension they found is comparable with the amount we noted in our log-roll condition, but they demonstrated more motion in lateral flexion and rotation than we did. These findings are consistent with our findings in that the log roll created significantly more motion in lateral flexion and rotation than did the other technique.

Other researchers have also analyzed the log roll.17,18 In 1987, McGuire et al18 employed radiographic techniques to analyze the log roll and use of a backboard and scoop stretcher for the amount of movement created in the thoracolumbar spine. The authors tested 3 subjects: a live, healthy female volunteer; an L1-L2 destabilized cadaver; and a patient with a recent T12-L1 fracture-dislocation. The healthy volunteer was log rolled, and anteroposterior (AP) radiographs were taken in the supine position and at the 90° apex. The cadaver was put through a similar procedure but was also transferred to a radiograph table by using a scoop stretcher. Lateral and AP radiographs were taken to measure the displacement at the site of injury. The injured patient was log rolled and underwent AP and lateral radiographs to measure displacement at the site of injury. The researchers found that the log roll produced a marked scoliotic curve in the thoracolumbar spine in the healthy volunteer. The cadaver demonstrated AP displacement of L1 on L2 of 2.1 cm, lateral displacement of 5 mm, and 30° of rotation through the fracture site. When the cadaver was placed on the backboard, the AP displacement was corrected, whereas the lateral and rotary displacement remained unchanged. When the injured patient was log rolled, no change in the AP plane occurred, but lateral displacement of 7 mm was noted at the site of injury. The authors concluded that even in a healthy volunteer, a 2.1-cm AP displacement in the spine could produce neurologic compromise, and an injured patient would almost certainly experience further neurologic deficit.18 Comparison with our study is difficult because the investigators were assessing low back as opposed to cervical spine displacement. This study by McGuire et al18 presented some early concern regarding the log-roll maneuver.

On the basis of the available literature, we have assumed that the head movement measured in our study resulted in movement in the cervical spine. Researchers have shown that motion at the head produces resultant cervical spine motion. Tierney et al22 studied the effect of head position and football equipment on cervical “space available for the spinal cord.” Using magnetic resonance imaging scans, they determined that changes in head position, specifically flexion and extension, resulted in changes in spinal cord cross-sectional area.22 It can be inferred that any change in head position will also affect the space available for the spinal cord. Information from another Tierney et al24 investigation indicates that the space available for the spinal cord ranges from 3 to 7 mm in normal subjects. Brimacombe et al13 assessed cervical spine motion at the C2-C3 level after destabilization of the C3 segment during 6 methods of airway management. Lennarson et al12 assessed segmental cervical spine motion in cadaver specimens during intubation techniques in intact and injured spines with and without external stabilization. Both groups found significant displacement of the injured cervical segments as a result of the airway-management techniques.12,13 Thus, with trauma to the cervical spine, any movement created during immobilization, treatment, or management can increase the risk of neurologic damage. These studies also confirm the importance of any method or device that might reduce this risk, especially in light of the fact that the unique nature of individual injuries prevents the prediction of a detrimental direction or amount of movement for any given patient.

Limitations

It is possible that the amount of movement in either condition is not a threat to exacerbate injury; that is, although the differences between the 2 conditions were statistically significant, they may not be of clinical significance. The “victim” in this study was a woman approximately 44.79 kg (120 lb) and 167.64 cm (5 ft, 6 in) tall. Data may not be generalizable to people with other height and weight characteristics. Also, the victim was not wearing any athletic equipment, and results may be influenced by the addition of padding or a helmet. Another potential limitation to external validity involves the prone subject at the head of the victim during the log roll. This is not the typical position taught or practiced for the log roll but was necessary in our study for tracking of markers. Last, the victim was not injured and had no underlying acute condition of the cervical spine. Conclusions as to the effects of either boarding technique in protecting or disturbing the integrity of the spinal segment should be carefully drawn. These points should be kept in mind when interpreting the results.

CONCLUSIONS

In a supine model wearing a properly fitted cervical collar, the MSB created less movement at the head than did the log roll in 2 planes of motion: frontal and transverse. The MSB appears to provide a safe alternative to the use of the log roll in stabilizing a spine-injured individual when operated by trained individuals. Future researchers should investigate the use of the MSB with multiple subjects of different anthropometric characteristics wearing various types of athletic equipment. Studies with injured subjects, though perhaps logistically impossible, would certainly provide important information on this topic.

Acknowledgments

We thank Jim Vailas, MD, of The New Hampshire Musculoskeletal Institute, Manchester, NH, for his support of this research. We also thank Sarah Calderone, ATC; Kevin Horn, ATC; and Becky Scanlon, ATC, for their assistance in piloting and data collection. We thank Karen Collins, PhD, from the University of New Hampshire for her assistance in the statistical analysis. We acknowledge Vision LLC for providing the MSB and funds for research supplies.

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