The Swimmer's view: Does it really show what it is supposed to show? A retrospective study

Abstract

One of the basic principles in the primary survey of a trauma patient is immobilisation of the cervical spine till cleared of any injury. Lateral cervical spine radiograph is one of the important initial radiographic assessments. More than often additional radiographs like the Swimmer's view are necessary for adequate visualisation of the cervical spine. How good is the Swimmer's view in visualisation of the cervical spine after an inadequate lateral cervical spine radiograph?
100 Swimmer's view radiographs randomly selected over a 2 year period in trauma patients were included for the study. All the patients had inadequate lateral cervical spine radiographs. The radiographs were assessed with regards to their adequacy by a single observer. The criteria for adequacy were adequate visualisation of the C7 body, C7/T1 junction and the soft tissue shadow.
Only 55% of the radiographs were adequate. None of the inadequate radiographs provided adequate visualisation of the C7 body and the C7/T1 junction. In 42.2% radiographs the soft tissue shadow was unclear. Poor exposure accounted for 53% of the inadequacies while overlapping bones accounted for the rest.
Clearing the cervical spine prior to removing triple immobilisation is essential in a trauma patient. This needs adequate visualisation from C1 to C7/T1 junction. In our study Swimmer's views did not satisfactorily provide adequate visualisation of the cervical spine in trauma patients. We recommend screening the cervical spine by a CT scan when the cervical spine lateral radiographs and Swimmer's views are inadequate.

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BMC Medical Imaging
Open Access
Research article
The Swimmer's view: does it really show what it is supposed to
show? A retrospective study
Ulfin Rethnam*, Rajam SU Yesupalan and Salah S Bastawrous
Address: Department of Orthopaedics, Glan Clwyd Hospital, Bodelwyddan, UK
Email: Ulfin Rethnam* - ulfinr@yahoo.com; Rajam SU Yesupalan - ajeesh2000@yahoo.co.uk; Salah S Bastawrous - Salah.bastawrous@cd-
tr.wales.nhs.uk
* Corresponding author
Abstract
Background: One of the basic principles in the primary survey of a trauma patient is
immobilisation of the cervical spine till cleared of any injury. Lateral cervical spine radiograph is one
of the important initial radiographic assessments. More than often additional radiographs like the
Swimmer's view are necessary for adequate visualisation of the cervical spine. How good is the
Swimmer's view in visualisation of the cervical spine after an inadequate lateral cervical spine
radiograph?
Methods: 100 Swimmer's view radiographs randomly selected over a 2 year period in trauma
patients were included for the study. All the patients had inadequate lateral cervical spine
radiographs. The radiographs were assessed with regards to their adequacy by a single observer.
The criteria for adequacy were adequate visualisation of the C7 body, C7/T1 junction and the soft
tissue shadow.
Results: Only 55% of the radiographs were adequate. None of the inadequate radiographs
provided adequate visualisation of the C7 body and the C7/T1 junction. In 42.2% radiographs the
soft tissue shadow was unclear. Poor exposure accounted for 53% of the inadequacies while
overlapping bones accounted for the rest.
Conclusion: Clearing the cervical spine prior to removing triple immobilisation is essential in a
trauma patient. This needs adequate visualisation from C1 to C7/T1 junction. In our study
Swimmer's views did not satisfactorily provide adequate visualisation of the cervical spine in trauma
patients. We recommend screening the cervical spine by a CT scan when the cervical spine lateral
radiographs and Swimmer's views are inadequate.
Background
Lateral cervical spine radiograph is one of the important
initial radiographic assessments among the three view
series in the trauma patient. An adequate lateral cervical
spine radiograph is a valuable projection in detecting cer-
vical spine injuries. The importance of visualizing the C7-
T1 junction in a patient with suspected cervical spine
injury cannot be understated. Visualising the cervical
spine from C1 to C7/T1 junction is of utmost importance
to avoid neurological deficit due to missed cervical spine
injuries. Missing a subluxation or dislocation at this junc-
tion can have dire consequences for the patient. Tradition-
Published: 15 January 2008
BMC Medical Imaging 2008, 8:2 doi:10.1186/1471-2342-8-2
Received: 10 July 2007
Accepted: 15 January 2008
This article is available from: http://www.biomedcentral.com/1471-2342/8/2
© 2008 Rethnam et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0
),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

BMC Medical Imaging 2008, 8:2 http://www.biomedcentral.com/1471-2342/8/2
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ally the Swimmer's view is used for visualizing the C7-T1
junction. It is used as an adjunct to lateral cervical spine
radiographs.
The Swimmer's view is the preferred additional view when
the lateral cervical spine radiograph is inadequate (the C7-
T1 junction is not clearly visualised). In trauma situations
getting an adequate lateral cervical spine is a difficult
proposition especially when the cervical spine is triply
immobilized. Thus the use of Swimmer's view has
increased. Does the Swimmer's view adequately reveal the
C7-T1 junction? The aim of our study was to assess this.
Methods
This was a retrospective study conducted in a district hos-
pital. Over a two year period 100 Swimmer's views from
the radiology archiving system were selected for the study.
Swimmer's views taken following inadequate lateral cervi-
cal spine radiographs in trauma patients were included in
the study. Radiographs taken in non trauma patients were
excluded from the study. The radiographs were assessed
on the digital imaging software Synapse. The selected
Swimmer's views were assessed for adequacy. The criteria
for adequacy were:
▪ Visualization of the C7 – T1 junction
▪ Visualization of the C7 & T1 vertebral body
▪ Visualization of the soft tissues anterior to the C7 & T1
vertebral bodies.
Data was collected from the archiving system (Synapse).
This software allowed better visualization of radiographs
by allowing change to the image quality for assessment of
the soft tissues, bones and by adjusting the contrast of the
image. The radiographs were assessed according to the cri-
teria of adequacy mentioned above. Radiographs were
deemed inadequate if there was improper visualization of
any of the three structures: the C7 – T1 junction, the C7 &
T1 vertebral body and the soft tissues anterior to the C7 &
T1 vertebral bodies. Image settings were adjusted using
the software (Synapse) for better visualization. After
assessment of adequacy, the reasons for inadequacy were
documented along with a count up of the inadequate
radiographs among the Swimmer's views.
Results
100 Swimmer's views were included in the study. 62
patients had concomitant injuries (femoral, tibial, ankle
and upper limb fractures) while the remaining patients
were suspected to have cervical spine injuries. 55/100
(55%) radiographs were found to be adequate (Figure 1).
45/100 (45%) radiographs were classified as inadequate
(Figure 2). Among the inadequate radiographs, the C7-T1
junction and the bodies of C7 and T1 vertebrae were not
clearly visualized in all radiographs and the soft tissues
were not clear in 19/45 (42.2%) radiographs. The reason
for inadequacy were poor exposure in 24/45 (53.3%)
radiographs and overlapping bone (humerus & clavicle)
in 21/45 (46.6%) radiographs (Table 1). No radiologi-
cally significant cervical spine injuries were detected from
any of the radiographs assessed or CT scans done follow-
ing inadequate plain radiographs.
Discussion
One of the basic principles in the primary survey of a
trauma patient is immobilisation of the cervical spine till
cleared of any injury. The lateral cervical spine radiograph
is part of the initial radiological survey for trauma patients
according to the Advanced Trauma Life Support (ATLS)
teachings. The lateral cervical spine radiograph is one of
the important initial radiographic assessments for the cer-
vical spine in trauma. Studies have mentioned varied neg-
ative predictive values of three view cervical spine series
(cervical spine anteroposterior, lateral & odontoid peg
Excellent Swimmer's viewFigure 1
Excellent Swimmer's view. Adequate visualisation of C7T1
junction, C7 & T1 bodies, soft tissues.

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view) in trauma patients (93% – 98%) although the sen-
sitivity has been lower (62.5% – 84%) [1-3].
The most significant consequence of premature discontin-
uation of cervical spine immobilization is neurological
injury. Prolonged immobilization, however, is associated
with morbidity as well. Decubitus ulcers, increased cere-
brospinal fluid pressure, pain and pulmonary complica-
tions have all been described with prolonged
immobilization of the cervical spine [4-6]. The single
most common cause of missed cervical spine injury
appears to be failure to adequately visualize the region of
injury. This can be caused by failure to obtain radio-
graphs, or by making judgments on technically subopti-
mal films. This occurs most commonly at the extremes of
the cervical spine, the occiput to C2 and at the C7-T1 lev-
els [7-9]. Visualising the C7-T1 junction is therefore
extremely important. In order to improve the visualiza-
tion of this region, various additional imaging modalities
have been recommended with the Swimmer's view being
the commonest [10-13].
There has been no study in the literature that assesses the
adequacy of the Swimmer's view on its own. Our study
aims to do this. There are studies comparing the supine
oblique views and the Swimmer's view but the results are
varied [14,15].
Our study showed that 45% of the Swimmer's view radio-
graphs were inadequate. Although this study has its limi-
tations (retrospective study, small sample), in light of our
findings we strongly believe that the Swimmer's view
should not be used as the imaging modality of choice to
visualize the C7-T1 junction prior to clearing the cervical
spine for removal of immobilization. In order to increase
the sensitivity of the radiographic assessment of the cervi-
cal spine in trauma patients, we recommend a CT or MR
evaluation of the cervical spine. The utility of these imag-
ing modalities for this purpose is well documented in the
literature [10-13]. If there is a high level of clinical suspi-
cion the sensitivity and specificity of a CT or an MRI scan
will be increased. The efficacy of a multislice CT or an MR
for screening of the cervical spine in obtunded patients is
well documented [16,17]. These modalities have been
found to be superior to dynamic radiography and plain
radiography [18,19]. MR imaging detects ligamentous
injuries in the cervical spine which can be missed on CT
scans [19,20].
In light of these facts and the findings from our study,
should we be performing the Swimmer's view at all? Is it
better to perform a CT evaluation of the cervical spine
prior to clearing the cervical spine?
Conclusion
The Swimmer's view is generally considered as the com-
monest additional view to supplement an inadequate lat-
eral cervical spine radiograph to visualize the cervical
spine [15]. Adequate visualization of the entire cervical
spine is essential in a trauma patient to prevent neurolog-
ical injury due to hasty removal of immobilization in a
missed cervical spine injury. We found the Swimmer's
Table 1: Swimmer's radiographs – inadequacies and reasons for inadequacy
Swimmer's view n = 100 Adequate – 55/100 (55%) Inadequate – 45/100 (45%)
Inadequate Swimmer's n = 45 C7/T1 junction & body not clear – 45/45 (100%) Soft tissues not clear – 19/45 (42.2%)
Reason for inadequacy Poor exposure 24/45 (53.3%) Overlapping bones – 21/45 (46.6%)
Inadequate swimmer's viewFigure 2
Inadequate swimmer's view. C7 and T1 bodies not visualised.
C7/T1junction not seen. Soft tissues not clear. Poor expo-
sure.

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view to be unreliable for this purpose and recommend
using other imaging modalities like CT or MR scans.
List of abbreviations
CT – Computed Tomography
MR – Magnetic Resonance
Competing interests
The author(s) declare that they have no competing inter-
ests.
Authors' contributions
UR, the main author was responsible for conducting the
study, acquisition, analysis and interpretation of the data
and preparing the manuscript.
RSUY, the co-author was responsible for literature review,
data acquisition and has approved the final draft.
SSB, the senior author was responsible for supervising the
study, proof reading of the manuscript and has approved
the final draft of the manuscript.
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