Prehospital Emergency Care
ISSN: 1090-3127 (Print) 1545-0066 (Online) Journal homepage: http://www.tandfonline.com/loi/ipec20
Motion Produced in the Unstable Cervical Spine by the HAINES and Lateral Recovery Positions Gianluca Del Rossi PhD, Dewayne Dubose MS, Nicole Scott PA-C, BS, Bryan P. Conrad PhD, Per Kristian Hyldmo MD, Glenn R. Rechtine MD & MaryBeth Horodsyki EdD To cite this article: Gianluca Del Rossi PhD, Dewayne Dubose MS, Nicole Scott PA-C, BS, Bryan P. Conrad PhD, Per Kristian Hyldmo MD, Glenn R. Rechtine MD & MaryBeth Horodsyki EdD (2014) Motion Produced in the Unstable Cervical Spine by the HAINES and Lateral Recovery Positions, Prehospital Emergency Care, 18:4, 539-543 To link to this article: http://dx.doi.org/10.3109/10903127.2014.916019
Published online: 30 May 2014.
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EDUCATION AND PRACTICE
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MOTION PRODUCED IN THE UNSTABLE CERVICAL SPINE BY THE HAINES AND LATERAL RECOVERY POSITIONS Gianluca Del Rossi, PhD, Dewayne Dubose, MS, Nicole Scott, PA-C, BS, Bryan P. Conrad, PhD, Per Kristian Hyldmo, MD, Glenn R. Rechtine, MD, MaryBeth Horodsyki, EdD ABSTRACT
Key words: spinal stabilization; spinal immobilization; cervical spine injury
Study objective. To compare the amount of segmental vertebral motion produced with the lateral recovery position and the HAINES technique when performed on cadavers with destabilized cervical spines. Methods. The cervical spines of 10 cadavers were surgically destabilized at the C5–C6 vertebral segment. Sensors from an electromagnetic tracking device were affixed to the vertebrae in question to monitor the amount of anterior/posterior, medial/lateral, and distraction/compression linear motion produced during the application of the two study techniques. Results. The statistical analysis of linear motion data did not reveal any significant differences between the two recovery positions. Conclusion. At this time, no single version of the recovery position can be endorsed for the spineinjured trauma patient. More research is needed to fully ascertain the safety of commonly used recovery positions.
PREHOSPITAL EMERGENCY CARE 2014;18:539–543
INTRODUCTION Basic life support guidelines advise placing unconscious patients who have a pulse and are breathing on their own into some kind of recovery position in order to maintain an open airway, maximize ventilations, and decrease the risk of aspiration.1,2 Over the past 20 years, a number of different recovery positions, all adhering to the same basic tenets, have been described. According to the International Liaison Committee on Resuscitation (ILCOR), there are six priorities for a recovery position: 1) the patient should be near true lateral position to permit fluid drainage from the mouth; 2) the position should be as stable as possible; 3) there should be no pressure on the chest to impair breathing; 4) the patient should be positioned so that returning him/her to the supine position is easy in case it becomes necessary to resume CPR; 5) workers must have a good view of, and access to, the airway; and 6) the position should not cause further injury to the patient.3 One of the earliest recovery positions to be described was the coma position.4 However, concerns related to patient safety eventually led to the adoption of other techniques that were deemed safer alternatives. Although the ILCOR does not promote any one specific position, at present, the lateral recovery position and the High Arm in Endangered Spine (HAINES) technique (along with their variants) appear to be the most widely accepted.1,5 Although most spinal injuries result from the trauma of the initial impact,6 there are reports in the literature describing the post-traumatic deterioration of both cervical and thoracolumbar spine injuries.7–10 Therefore, to lessen the probability of generating secondary
Received November 7, 2013 from the University of South Florida, Department of Orthopaedics and Sports Medicine, Tampa, Florida (GDR), University of Florida, Department of Orthopedics, Gainesville, Florida (DD, BPC, MBH), Florida Cancer Specialists and Research Institute, Fort Myers, Florida (NS), Norwegian Air Ambulance Foundation, Drøbak, Norway (PKH), Department of Health Studies, Faculty of Social Sciences, University of Stavanger, Stavanger, Norway (PKH), and University of Rochester, Department of Orthopaedics, Rochester, New York (GRR). Revision received April 3, 2014; accepted for publication April 3, 2014.
Author contributions: GD, MH, NS, BPC, and GRR conceived the study, designed the study, and obtained research funding. GD, DD, MH, GRR, NS, BPC, and PKH collected and managed the data, including quality control. GD drafted the manuscript, and all authors (DD, MH, GRR, NS, BPC, PKH) contributed substantially to its revision. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Address correspondence to Gianluca Del Rossi, PhD, University of South Florida, Department of Orthopaedics and Sports Medicine, 13220 USF Laurel Dr., MDF 5117, MDC 106, Tampa, FL 33612 USA. doi: 10.3109/10903127.2014.916019
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neurologic injuries following spinal trauma, management guidelines stipulate that the entire spinal column be immobilized and protected until diagnostic imaging and definitive management can be initiated. In the prehospital setting, it is standard procedure to fit a potential or actual spine-injured patient with a cervical collar and then secure the individual to a spine board using a head immobilization device and straps so as to achieve full spinal immobilization. Unfortunately, at times, when rendering prehospital care, situations may arise whereby a patient with a potential spine injury may need to be moved prior to the provision of rigid mechanical immobilization. For example, a trauma patient whose airway cannot be maintained while in the supine position may need to be moved to the recovery position before the immobilization process can be completed. Naturally, during these rare situations it would be best to use a recovery position that can provide a stable airway while keeping the risk for secondary spinal injury to a minimum. To our knowledge, very few empirical data are available to practitioners regarding the safety of recovery positions for use on trauma or spine-injured patients. All existing research data have been obtained from a limited number of studies that were performed on healthy participants (fully conscious and without spinal instability).11,12 While this previous research may be a good indicator of the general consequences that the lateral recovery position and the HAINES technique may have on the spine, they are unable to define the potentially deleterious effects these positions might have on the structural arrangement of a destabilized or clinically unstable spine. In order to determine the most appropriate technique to use on spine-injured patients, we sought to compare the amount of segmental motion produced with the lateral recovery position and the HAINES technique when applied to cadavers with destabilized cervical spines.
METHODS In this cadaveric investigation, a repeated measures design was employed to fully elucidate how the vertebrae of patients with clinically unstable spinal segments shift when placed in the recovery position. Institutional review board approval was sought for this investigation and granted by the University of Rochester (Rochester, NY). Ten cadavers (6 male, 4 female) with no previous history of cervical spine pathology were included in this laboratory investigation. The mean age and weight of the cadavers was 73.5 ± 15.0 years and 61.3 ± 10.45 kg, respectively. For this study, a complete segmental injury (resulting in global instability) was surgically created at the cervical spine region of all cadavers. The cervical spine lesion was created by excising
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FIGURE 1. Lateral recovery position.
the supraspinous and interspinous ligaments, the ligamentum flavum, the spinal cord, the facet capsules, and the anterior and posterior longitudinal ligament along with the intervertebral disc. To standardize the injury conditions, one spine surgeon generated all experimental lesions at the C5–C6 spinal segment. All cadavers were placed into the lateral recovery position and HAINES position. For the lateral recovery position, cadavers were rolled onto one side with the nearside arm in the 90/90 “How” position. Prior to moving the cadavers, the far arm was placed across the body and under the cheek. The far side leg was flexed so that the knee was at approximately 90 degrees of knee flexion, the hip flexed to 45 degrees, and the foot flat on the floor. The cadavers’ flexed leg was then pulled over while protecting the head to reduce movement of the cervical spine (Figure 1). For the HAINES position the cadavers were placed into a side-lying position with the head resting on the upper limb, which was placed in a fully abducted position. Additionally, both lower limbs were flexed at the hip and knees prior to rolling the cadavers, resulting in one leg lying on top of the other. Finally, with the HAINES position, the uppermost upper limb was placed along the trunk/torso rather than in front of the cadaver (Figure 2). The order of testing for recovery position was randomized using a computer-generated random numbers list. All recovery positions were repeated 3 times with each cadaver and began with the cadaver in a standard starting position, which consisted of the cadaver lying supine on the ground and the head and neck aligned with the torso. To minimize the level of
FIGURE 2. HAINES position.
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fatigue experienced by the tester, only 1–2 cadavers were tested on any given day. An electromagnetic tracking device (Liberty, Polhemus, Colchester, VT) was used to capture all linear translation motions produced between the C5–C6 segment. Sensors for the Liberty system were attached to C5 and the C6 vertebrae using standard wood screws and plastic small cable ties. The maximum capture volume for the electromagnetic tracking system is a hemisphere with a radius of approximately 79 cm. For this study, the transmitter for the tracking system was placed within the thoracic cavity. This strategic placement of the transmitter allowed for the sensors to remain within sufficient range so as to maintain the accuracy of the system. Following the attachment of all sensors and placement of the transmitter within the thoracic cavity, cadavers were carefully positioned into each of the two recovery positions in random order. During this time the following segmental motions were recorded: axial distraction–compression (DC), medial–lateral translation (ML), and anteroposterior translation (AP) (Figure 3). The peak or maximum range of motion obtained from each of the three trials and for each recovery position were calculated for each cadaver and the average of those peak values calculated from all cadavers was then included in all statistical tests. Depending on the distribution of the data, either a paired-samples t-test or related samples Wilcoxon signed rank test was used to compare the mean difference between the two recovery positions for each of the 3 types of motion (medial–lateral, distraction–compression, and anterior–posterior translation). All statistical analyses were performed using SPSS statistical software (SPSS, version 21.0, Chicago, IL) with the level of significance for all statistical tests set, a priori, at α ≤ 0.05.
RESULTS Data from the analysis of all trials are summarized in Table 1. The Shapiro-Wilk test of normality was used to determine if the data were normally distributed. With the exception of the medial–lateral data obtained with the lateral recovery position, all other data were found to be normally distributed. No statistically significant results were identified in this study (Table 1).
DISCUSSION All previous research on recovery positions has indicated that the HAINES technique, which entails placing one arm above the head (shoulder abduction) to help support the patient’s head and neck, appears to be the most appropriate to use when cervical spine injuries are suspected. Previously, Gunn et al.12
FIGURE 3. Variables of interest. (a) Medial/lateral translation, (b) anterior/posterior displacement, (c) axial distraction/compression.
combined digital image analysis and fluoroscopy to demonstrate that the dimensions of the airway were equivalent between the lateral recovery position and the HAINES technique, but the supporting abducted arm (HAINES) helped reduce the amount of lateral flexion of the cervical spine from 28 to 11 degrees. Similarly, Blake et al.11 reported that the modified HAINES TABLE 1. Summary of linear translation data in millimeters (SD) Type of motion
Medial/lateral Compression/ distraction Anterior/posterior SD, standard deviation; n = 10.
Lateral recovery
HAINES
Difference
P-value
7.62 (5.52) 9.74 (3.81) 8.00 (3.84)
6.52 (3.56) 8.68 (1.92) 7.76 (2.13)
1.09 (3.32) 1.06 (3.38) 0.24 (2.85)
.285 .346 .798
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technique also offered a large improvement in the position of the cervical spine as compared to the lateral recovery position, with 13 degrees less extension and a 13-degree reduction in lateral flexion. Despite these preliminary findings, the HAINES technique has not been universally accepted within the emergency medicine field. Unlike previously published studies conducted on healthy individuals, to further elucidate the safety of commonly taught recovery positions, we subjected cadaveric specimens to these techniques. In using a cadaveric model for our study we were able to evaluate how the destabilized cervical spine reacts or shifts during the execution of both the lateral recovery and HAINES position. That is, by using cadavers we were able to artificially create a more representative situation in which we modeled an unconscious patient with cervical spine instability who was moved without the benefit of rigid inline stabilization. Sensors mounted directly onto vertebral segments then allowed us to evaluate the quality and quantity of linear vertebral motion produced across a destabilized spinal segment. Given the findings from previous research, we were somewhat surprised to find the lateral recovery position did not result in significantly greater segmental displacement when compared to the HAINES, especially considering that Gunn et al.11 had reported that most of the cervical spine motion observed in their study actually occurred within the lower part of the cervical spine. Specifically, Gunn et al.11 reported that in one participant up to 4 times more motion was induced along the lower cervical spine as compared to the upper spine. It is possible that we did not see a significant difference in motion between the lateral recovery position and HAINES because rather than use the standard lateral recovery position, we used the 1992 European Resuscitation Council (ERC) guidelines (“How”) recovery position which involved tucking the hand of the far side arm beneath the cheek or face of the cadaver,2,13 whereas the version employed in previous studies involved placing the arm on the ground so as not to be loaded and compressed by the weight of the head.11–12 We believe that tucking the hand beneath the head reduced the amount the cervical spine tilted into lateral flexion in the side-lying position. And although the 1992 ERC recovery position has reportedly been associated with neuropraxia14 and circulatory disturbances15,16 when maintained for long periods of time, it was selected for this investigation as it was believed to better support the cervical spine in the side-lying position. Yet another unexpected finding was the overall magnitude of motion produced by both techniques. Indeed, the amount of motion that resulted from the execution of either technique appears quite large when one considers the average sagittal canal diam-
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eter at C5 to be 14.5 ± 2.96 mm, and the average anterior–posterior spinal cord diameter has been reported from previous studies to average 7.3 mm at C5.17–21 Given these estimates, and based on our data, the 7–8 mm of AP displacement that resulted with either technique not only could have potentially occluded the space available for the cord in the average individual, but could also have resulted in static compression of the spinal cord. This is problematic because it is well established (based on animal models) that the severity of neurologic injury has been shown to be dependent not only on the magnitude and the rate of spinal cord compression,22,23 but also on the static compression occurring early on after the onset of the spinal cord injury.24,25 In truth, one must keep in mind that even though the amount of linear motion produced during the application of the recovery positions in this study was seemingly high, life-saving medical procedures always take precedence over a spinal injury, and so if at any point in time it becomes necessary to maintain an open airway in a spine-injured patient, positioning the individual into a recovery position should be attempted with the understanding that there is potential for considerable spinal motion. All investigations have limitations that affect the generalizability of the results because of the methods used in the study. The various methodologic limitations of our investigation include the use of cadaver specimens that were significantly older than typical patients and likely smaller. With advanced age, the mobility of human tissue changes,26 and this may have affected the amount of motion produced throughout the study. Moreover, even though the use of fresh cadavers allows researchers to surgically create lesions anywhere along the spinal column, one cannot expect the spinal motion of a cadaver to display similarities to the motion produced by a living patient. Along with the limits of generalizability related to the cadaver specimens, other factors also need to be considered. In our study, we induced a spinal column injury that would mimic a worst-case clinical situation; that is, we generated a complete segmental spine injury that resulted in global instability at a single level of the spine. This represents a fraction of all the possible clinical conditions and, as such, the results of this study cannot be used to predict how different injuries or clinical conditions would respond to the recovery positions tested in this investigation. However, in creating a worst-case scenario, it is presumed that all other injury types or clinical situations would likely generate less motion than that which was produced using our injury model. Finally, we also acknowledge that a study with a larger sample of cadaver specimens could have possibly identified a significant difference in motion between the two recovery positions tested in this study.
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CONCLUSIONS
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In summary, sensors mounted directly to vertebral segments in the cervical spine allowed us to evaluate the quality and quantity of motion produced across a destabilized spine while positioning cadavers into either the lateral recovery or HAINES position. Because the statistical analysis of our data did not reveal any significant differences between recovery positions and since both recovery positions tested in this study comply with the basic principles put forth by the ILCOR, no single version can be endorsed at this time. More research is needed to fully ascertain the safety of commonly used recovery positions.
References 1.
Berg RA, Hemphil R, Abella BS, Aufderheide TP, Cave DM, Hazinski MF, Lerner EB, Rea TD, Sayre MR, Swor RA. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science, Part 5: Adult Basic Life Support. Circulation. 2010;122:S685–705. 2. Turner S, Turner I, Chapman D, Howard P, Champion P, Hatfield J, James A, Marshall S, Barber S. A comparative study of the 1992 and 1997 recovery positions for use in the UK. Resuscitation. 1998;39(3):153–60. 3. Handley AJ, Becker LB, Allen M, van Drenth A, Kramer EB, Montgomery WH. Single-rescuer adult basic life support: an advisory statement from the Basic Life Support Working group of the International Liaison Committee on Resuscitation. Circulation. 1997;95:2174–9. 4. Pressley M, MacDonald L, eds. Australian First Aid. Melbourne: Ruskin Press, 1984: 48–82. 5. Nolan JP, Soar J, Zideman DA, Biarent D, Bossaert LL, ¨ Deakin C, Koster RW, Wyllie J, Bottiger B; ERC Guidelines Writing Group. European Resuscitation Council Guidelines for Resuscitation 2010 (Executive Summary). Resuscitation. 2010;81:1219–76. 6. Hauswald M, Ong G, Tandberg D, Omar Z. Out-of-hospital spinal immobilization: its effect on neurologic injury. Acad Emerg Med. 1998;5:214–9. 7. Gertzbein SD. Neurologic deterioration in patients with thoracic and lumbar fractures after admission to the hospital. Spine. 1994;19:1723–5. 8. Harrop JS, Sharan AD, Vaccaro AR, Przybylski GJ. The cause of neurologic deterioration after acute cervical spinal cord injury. Spine. 2001;26(4):340–6. 9. Levi AD, Hurlbert RJ, Anderson P, Fehlings M, Rampersaud R, Massicotte EM, France JC, Le Huec JC, Hedlund R, Arnold P. Neurologic deterioration secondary to unrecognized spinal instability following trauma – a multicenter study. Spine. 2006;31:451–8.
543 10. Powell RM, Heath KJ. Quadriplegia in a patient with an undiagnosed odontoid peg fracture: the importance of cervical spine immobilization in patients with head injuries. J Army Med Corps. 1996;142:79–81. 11. Blake WED, Stillman BC, Eizenberg N, Briggs C, McMeeken JM. The position of the spine in the recovery position–an experimental comparison between the lateral recovery position and the modified HAINES position. Resuscitation. 2002;53(3):289–97. 12. Gunn BD, Eizenberg N, Silberstein M, McMeeken JM, Tully EA, Stillman BC, Brown DJ, Gutteridge GA. How should an unconscious person with a suspected neck injury be positioned? Prehosp Disaster Med. 1995;10(4):239–44. 13. Doxey J. Comparing 1997 Resuscitation Council (UK) recovery position with recovery position of 1992 European Resuscitation Council guidelines: a user’s perspective. Resuscitation. 1998;39(3):161–9. 14. Kumar P, Touquet R. Perils of the recovery position: neuropraxia of the radial and common peroneal nerve. Emerg Med J. 1996;13:69–70. 15. Fulstow R, Smith GB. The new recovery position, a cautionary tale. Resuscitation. 1993;26:89–91. ¨ 16. Rathgeber J, Panzer W, Gunther U, Scholz M, Hoeft A, Bahr J, Kettler D. Influence of different types of recovery positions on perfusion indices of the forearm. Resuscitation. 1996;32(1):13–7. 17. Devkota J, El Gammal T, Lucke JF. Measurement of the normal cervical cord by metrizamide myelography. South Med J. 1982;75:1363–5. 18. Inoue H, Ohmori K, Takatsu T, Teramoto T, Ishida Y, Suzuki K. Morphological analysis of the cervical spinal canal, dural tube and spinal cord in normal individuals using CT myelography. Neuroradiology. 1996;38:148–51. 19. Kameyama T, Hashizume Y, Sobue G. Morphologic features of the normal human cadaveric spinal cord. Spine. 1996;21:1285–90. 20. Nordquist L. The sagittal diameter of the spinal cord and subarachnoid space in different age groups. Acta Radiol Suppl. 1964;227:1–96. 21. Thijssen HO, Keyser A, Horstink MW, Meijer E. Morphology of the cervical spinal cord on computed myelography. Neuroradiology. 1979;18:57–62. 22. Anderson TE. A controlled pneumatic technique for experimental spinal cord contusion. J Neurosci Methods. 1982;6:327–33. 23. Kearney PA, Ridella SA, Viano DC, Anderson TE. Interaction of contact velocity and cord compression in determining the severity of spinal cord injury. J Neurotrauma. 1988;5(3):187–208. 24. Guha A, Tator CH, Endrenyi L, Piper I. Decompression of the spinal cord improves recovery after acute experimental spinal cord compression injury. Paraplegia. 1987;25(4):324–39. 25. Swartz KR, Scheff NN, Roberts KN, Fee DB. Exacerbation of spinal cord injury due to static compression occurring early after onset. J Neurosurg Spine. 2009;11(5):570–4. 26. Gastel JA, Palumbo MA, Hulstyn MJ, Fadale PD, Lucas P. Emergency removal of football equipment: a cadaveric cervical spine injury model. Ann Emerg Med. 1998:32(4):411–7.
ISSN: 1090-3127 (Print) 1545-0066 (Online) Journal homepage: http://www.tandfonline.com/loi/ipec20
Motion Produced in the Unstable Cervical Spine by the HAINES and Lateral Recovery Positions Gianluca Del Rossi PhD, Dewayne Dubose MS, Nicole Scott PA-C, BS, Bryan P. Conrad PhD, Per Kristian Hyldmo MD, Glenn R. Rechtine MD & MaryBeth Horodsyki EdD To cite this article: Gianluca Del Rossi PhD, Dewayne Dubose MS, Nicole Scott PA-C, BS, Bryan P. Conrad PhD, Per Kristian Hyldmo MD, Glenn R. Rechtine MD & MaryBeth Horodsyki EdD (2014) Motion Produced in the Unstable Cervical Spine by the HAINES and Lateral Recovery Positions, Prehospital Emergency Care, 18:4, 539-543 To link to this article: http://dx.doi.org/10.3109/10903127.2014.916019
Published online: 30 May 2014.
Submit your article to this journal
Article views: 123
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Date: 05 November 2015, At: 17:41
EDUCATION AND PRACTICE
Downloaded by [University of Wisconsin Oshkosh] at 17:41 05 November 2015
MOTION PRODUCED IN THE UNSTABLE CERVICAL SPINE BY THE HAINES AND LATERAL RECOVERY POSITIONS Gianluca Del Rossi, PhD, Dewayne Dubose, MS, Nicole Scott, PA-C, BS, Bryan P. Conrad, PhD, Per Kristian Hyldmo, MD, Glenn R. Rechtine, MD, MaryBeth Horodsyki, EdD ABSTRACT
Key words: spinal stabilization; spinal immobilization; cervical spine injury
Study objective. To compare the amount of segmental vertebral motion produced with the lateral recovery position and the HAINES technique when performed on cadavers with destabilized cervical spines. Methods. The cervical spines of 10 cadavers were surgically destabilized at the C5–C6 vertebral segment. Sensors from an electromagnetic tracking device were affixed to the vertebrae in question to monitor the amount of anterior/posterior, medial/lateral, and distraction/compression linear motion produced during the application of the two study techniques. Results. The statistical analysis of linear motion data did not reveal any significant differences between the two recovery positions. Conclusion. At this time, no single version of the recovery position can be endorsed for the spineinjured trauma patient. More research is needed to fully ascertain the safety of commonly used recovery positions.
PREHOSPITAL EMERGENCY CARE 2014;18:539–543
INTRODUCTION Basic life support guidelines advise placing unconscious patients who have a pulse and are breathing on their own into some kind of recovery position in order to maintain an open airway, maximize ventilations, and decrease the risk of aspiration.1,2 Over the past 20 years, a number of different recovery positions, all adhering to the same basic tenets, have been described. According to the International Liaison Committee on Resuscitation (ILCOR), there are six priorities for a recovery position: 1) the patient should be near true lateral position to permit fluid drainage from the mouth; 2) the position should be as stable as possible; 3) there should be no pressure on the chest to impair breathing; 4) the patient should be positioned so that returning him/her to the supine position is easy in case it becomes necessary to resume CPR; 5) workers must have a good view of, and access to, the airway; and 6) the position should not cause further injury to the patient.3 One of the earliest recovery positions to be described was the coma position.4 However, concerns related to patient safety eventually led to the adoption of other techniques that were deemed safer alternatives. Although the ILCOR does not promote any one specific position, at present, the lateral recovery position and the High Arm in Endangered Spine (HAINES) technique (along with their variants) appear to be the most widely accepted.1,5 Although most spinal injuries result from the trauma of the initial impact,6 there are reports in the literature describing the post-traumatic deterioration of both cervical and thoracolumbar spine injuries.7–10 Therefore, to lessen the probability of generating secondary
Received November 7, 2013 from the University of South Florida, Department of Orthopaedics and Sports Medicine, Tampa, Florida (GDR), University of Florida, Department of Orthopedics, Gainesville, Florida (DD, BPC, MBH), Florida Cancer Specialists and Research Institute, Fort Myers, Florida (NS), Norwegian Air Ambulance Foundation, Drøbak, Norway (PKH), Department of Health Studies, Faculty of Social Sciences, University of Stavanger, Stavanger, Norway (PKH), and University of Rochester, Department of Orthopaedics, Rochester, New York (GRR). Revision received April 3, 2014; accepted for publication April 3, 2014.
Author contributions: GD, MH, NS, BPC, and GRR conceived the study, designed the study, and obtained research funding. GD, DD, MH, GRR, NS, BPC, and PKH collected and managed the data, including quality control. GD drafted the manuscript, and all authors (DD, MH, GRR, NS, BPC, PKH) contributed substantially to its revision. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Address correspondence to Gianluca Del Rossi, PhD, University of South Florida, Department of Orthopaedics and Sports Medicine, 13220 USF Laurel Dr., MDF 5117, MDC 106, Tampa, FL 33612 USA. doi: 10.3109/10903127.2014.916019
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neurologic injuries following spinal trauma, management guidelines stipulate that the entire spinal column be immobilized and protected until diagnostic imaging and definitive management can be initiated. In the prehospital setting, it is standard procedure to fit a potential or actual spine-injured patient with a cervical collar and then secure the individual to a spine board using a head immobilization device and straps so as to achieve full spinal immobilization. Unfortunately, at times, when rendering prehospital care, situations may arise whereby a patient with a potential spine injury may need to be moved prior to the provision of rigid mechanical immobilization. For example, a trauma patient whose airway cannot be maintained while in the supine position may need to be moved to the recovery position before the immobilization process can be completed. Naturally, during these rare situations it would be best to use a recovery position that can provide a stable airway while keeping the risk for secondary spinal injury to a minimum. To our knowledge, very few empirical data are available to practitioners regarding the safety of recovery positions for use on trauma or spine-injured patients. All existing research data have been obtained from a limited number of studies that were performed on healthy participants (fully conscious and without spinal instability).11,12 While this previous research may be a good indicator of the general consequences that the lateral recovery position and the HAINES technique may have on the spine, they are unable to define the potentially deleterious effects these positions might have on the structural arrangement of a destabilized or clinically unstable spine. In order to determine the most appropriate technique to use on spine-injured patients, we sought to compare the amount of segmental motion produced with the lateral recovery position and the HAINES technique when applied to cadavers with destabilized cervical spines.
METHODS In this cadaveric investigation, a repeated measures design was employed to fully elucidate how the vertebrae of patients with clinically unstable spinal segments shift when placed in the recovery position. Institutional review board approval was sought for this investigation and granted by the University of Rochester (Rochester, NY). Ten cadavers (6 male, 4 female) with no previous history of cervical spine pathology were included in this laboratory investigation. The mean age and weight of the cadavers was 73.5 ± 15.0 years and 61.3 ± 10.45 kg, respectively. For this study, a complete segmental injury (resulting in global instability) was surgically created at the cervical spine region of all cadavers. The cervical spine lesion was created by excising
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FIGURE 1. Lateral recovery position.
the supraspinous and interspinous ligaments, the ligamentum flavum, the spinal cord, the facet capsules, and the anterior and posterior longitudinal ligament along with the intervertebral disc. To standardize the injury conditions, one spine surgeon generated all experimental lesions at the C5–C6 spinal segment. All cadavers were placed into the lateral recovery position and HAINES position. For the lateral recovery position, cadavers were rolled onto one side with the nearside arm in the 90/90 “How” position. Prior to moving the cadavers, the far arm was placed across the body and under the cheek. The far side leg was flexed so that the knee was at approximately 90 degrees of knee flexion, the hip flexed to 45 degrees, and the foot flat on the floor. The cadavers’ flexed leg was then pulled over while protecting the head to reduce movement of the cervical spine (Figure 1). For the HAINES position the cadavers were placed into a side-lying position with the head resting on the upper limb, which was placed in a fully abducted position. Additionally, both lower limbs were flexed at the hip and knees prior to rolling the cadavers, resulting in one leg lying on top of the other. Finally, with the HAINES position, the uppermost upper limb was placed along the trunk/torso rather than in front of the cadaver (Figure 2). The order of testing for recovery position was randomized using a computer-generated random numbers list. All recovery positions were repeated 3 times with each cadaver and began with the cadaver in a standard starting position, which consisted of the cadaver lying supine on the ground and the head and neck aligned with the torso. To minimize the level of
FIGURE 2. HAINES position.
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fatigue experienced by the tester, only 1–2 cadavers were tested on any given day. An electromagnetic tracking device (Liberty, Polhemus, Colchester, VT) was used to capture all linear translation motions produced between the C5–C6 segment. Sensors for the Liberty system were attached to C5 and the C6 vertebrae using standard wood screws and plastic small cable ties. The maximum capture volume for the electromagnetic tracking system is a hemisphere with a radius of approximately 79 cm. For this study, the transmitter for the tracking system was placed within the thoracic cavity. This strategic placement of the transmitter allowed for the sensors to remain within sufficient range so as to maintain the accuracy of the system. Following the attachment of all sensors and placement of the transmitter within the thoracic cavity, cadavers were carefully positioned into each of the two recovery positions in random order. During this time the following segmental motions were recorded: axial distraction–compression (DC), medial–lateral translation (ML), and anteroposterior translation (AP) (Figure 3). The peak or maximum range of motion obtained from each of the three trials and for each recovery position were calculated for each cadaver and the average of those peak values calculated from all cadavers was then included in all statistical tests. Depending on the distribution of the data, either a paired-samples t-test or related samples Wilcoxon signed rank test was used to compare the mean difference between the two recovery positions for each of the 3 types of motion (medial–lateral, distraction–compression, and anterior–posterior translation). All statistical analyses were performed using SPSS statistical software (SPSS, version 21.0, Chicago, IL) with the level of significance for all statistical tests set, a priori, at α ≤ 0.05.
RESULTS Data from the analysis of all trials are summarized in Table 1. The Shapiro-Wilk test of normality was used to determine if the data were normally distributed. With the exception of the medial–lateral data obtained with the lateral recovery position, all other data were found to be normally distributed. No statistically significant results were identified in this study (Table 1).
DISCUSSION All previous research on recovery positions has indicated that the HAINES technique, which entails placing one arm above the head (shoulder abduction) to help support the patient’s head and neck, appears to be the most appropriate to use when cervical spine injuries are suspected. Previously, Gunn et al.12
FIGURE 3. Variables of interest. (a) Medial/lateral translation, (b) anterior/posterior displacement, (c) axial distraction/compression.
combined digital image analysis and fluoroscopy to demonstrate that the dimensions of the airway were equivalent between the lateral recovery position and the HAINES technique, but the supporting abducted arm (HAINES) helped reduce the amount of lateral flexion of the cervical spine from 28 to 11 degrees. Similarly, Blake et al.11 reported that the modified HAINES TABLE 1. Summary of linear translation data in millimeters (SD) Type of motion
Medial/lateral Compression/ distraction Anterior/posterior SD, standard deviation; n = 10.
Lateral recovery
HAINES
Difference
P-value
7.62 (5.52) 9.74 (3.81) 8.00 (3.84)
6.52 (3.56) 8.68 (1.92) 7.76 (2.13)
1.09 (3.32) 1.06 (3.38) 0.24 (2.85)
.285 .346 .798
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technique also offered a large improvement in the position of the cervical spine as compared to the lateral recovery position, with 13 degrees less extension and a 13-degree reduction in lateral flexion. Despite these preliminary findings, the HAINES technique has not been universally accepted within the emergency medicine field. Unlike previously published studies conducted on healthy individuals, to further elucidate the safety of commonly taught recovery positions, we subjected cadaveric specimens to these techniques. In using a cadaveric model for our study we were able to evaluate how the destabilized cervical spine reacts or shifts during the execution of both the lateral recovery and HAINES position. That is, by using cadavers we were able to artificially create a more representative situation in which we modeled an unconscious patient with cervical spine instability who was moved without the benefit of rigid inline stabilization. Sensors mounted directly onto vertebral segments then allowed us to evaluate the quality and quantity of linear vertebral motion produced across a destabilized spinal segment. Given the findings from previous research, we were somewhat surprised to find the lateral recovery position did not result in significantly greater segmental displacement when compared to the HAINES, especially considering that Gunn et al.11 had reported that most of the cervical spine motion observed in their study actually occurred within the lower part of the cervical spine. Specifically, Gunn et al.11 reported that in one participant up to 4 times more motion was induced along the lower cervical spine as compared to the upper spine. It is possible that we did not see a significant difference in motion between the lateral recovery position and HAINES because rather than use the standard lateral recovery position, we used the 1992 European Resuscitation Council (ERC) guidelines (“How”) recovery position which involved tucking the hand of the far side arm beneath the cheek or face of the cadaver,2,13 whereas the version employed in previous studies involved placing the arm on the ground so as not to be loaded and compressed by the weight of the head.11–12 We believe that tucking the hand beneath the head reduced the amount the cervical spine tilted into lateral flexion in the side-lying position. And although the 1992 ERC recovery position has reportedly been associated with neuropraxia14 and circulatory disturbances15,16 when maintained for long periods of time, it was selected for this investigation as it was believed to better support the cervical spine in the side-lying position. Yet another unexpected finding was the overall magnitude of motion produced by both techniques. Indeed, the amount of motion that resulted from the execution of either technique appears quite large when one considers the average sagittal canal diam-
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eter at C5 to be 14.5 ± 2.96 mm, and the average anterior–posterior spinal cord diameter has been reported from previous studies to average 7.3 mm at C5.17–21 Given these estimates, and based on our data, the 7–8 mm of AP displacement that resulted with either technique not only could have potentially occluded the space available for the cord in the average individual, but could also have resulted in static compression of the spinal cord. This is problematic because it is well established (based on animal models) that the severity of neurologic injury has been shown to be dependent not only on the magnitude and the rate of spinal cord compression,22,23 but also on the static compression occurring early on after the onset of the spinal cord injury.24,25 In truth, one must keep in mind that even though the amount of linear motion produced during the application of the recovery positions in this study was seemingly high, life-saving medical procedures always take precedence over a spinal injury, and so if at any point in time it becomes necessary to maintain an open airway in a spine-injured patient, positioning the individual into a recovery position should be attempted with the understanding that there is potential for considerable spinal motion. All investigations have limitations that affect the generalizability of the results because of the methods used in the study. The various methodologic limitations of our investigation include the use of cadaver specimens that were significantly older than typical patients and likely smaller. With advanced age, the mobility of human tissue changes,26 and this may have affected the amount of motion produced throughout the study. Moreover, even though the use of fresh cadavers allows researchers to surgically create lesions anywhere along the spinal column, one cannot expect the spinal motion of a cadaver to display similarities to the motion produced by a living patient. Along with the limits of generalizability related to the cadaver specimens, other factors also need to be considered. In our study, we induced a spinal column injury that would mimic a worst-case clinical situation; that is, we generated a complete segmental spine injury that resulted in global instability at a single level of the spine. This represents a fraction of all the possible clinical conditions and, as such, the results of this study cannot be used to predict how different injuries or clinical conditions would respond to the recovery positions tested in this investigation. However, in creating a worst-case scenario, it is presumed that all other injury types or clinical situations would likely generate less motion than that which was produced using our injury model. Finally, we also acknowledge that a study with a larger sample of cadaver specimens could have possibly identified a significant difference in motion between the two recovery positions tested in this study.
G. Del Rossi et al.
MOTION WITH HAINES AND LATERAL RECOVERY POSITIONS
CONCLUSIONS
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In summary, sensors mounted directly to vertebral segments in the cervical spine allowed us to evaluate the quality and quantity of motion produced across a destabilized spine while positioning cadavers into either the lateral recovery or HAINES position. Because the statistical analysis of our data did not reveal any significant differences between recovery positions and since both recovery positions tested in this study comply with the basic principles put forth by the ILCOR, no single version can be endorsed at this time. More research is needed to fully ascertain the safety of commonly used recovery positions.
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