19. Acute back pain


A diagnostic algorithm is derived based on whether acute back pain is traumatic or non-traumatic.
Diseases of organs other than the spine, which may present with back pain, should also be
considered in the context of differential diagnosis.


Trauma of the spine

The basic diagnostic modality for the detection of traumatic changes in the spine remains X-ray of
the spine performed in two standard projections (anteroposterior and lateral), mainly due to the
possibility of examination of long sections of the spina (eventually the whole spine) and a
relatively low radiation dose. The sensitivity of X-ray examination is undoubtedly lower compared
to CT, which, however, when examining large sections of the spine (e.g. thoracic and lubar) burdens
the patient with a much higher radiation dose compared to X-ray, so this indication is not
justified as a method of first choice. An exception is whole-body CT performed in polytraumatized
patients, which provides a detailed assessment of the skeleton of the entire spine. The indication
of this examination is given by the assumption of the presence of other life-threatening injuries
(chest, parenchymal organs), which justifies the application of a higher radiation dose.

If trauma on X-ray is suspected or in case of unclear findings (eventually in case of insufficient
clarity of some sections of the spine), the CT examination is indicated specifically for selected
levels of the spine. CT makes it possible to detect skeletal fracture lines with very high
sensitivity, to classify the type of fracture (Fig. 1) and to assess the possible prominence of
bone fragments into the spinal canal. A general limitation of CT is the relatively low contrast of
soft tissues, so this method is not suitable for the detection of discoligamentous injury.


The last of the available methods is MR examination, which does not burden the patient with
radiation and allows examination of long segments of the spine in an acceptable time. Indications
of MR is reserved for traumatic conditions in which the patient have a significant neurological
deficit that is not explained by the finding on CT. In such a case, we look for signs of
discoligamentous trauma, such as traumatic disc herniation with compression of the spinal cord or
nerve roots (Fig. 2). Fresh traumatic changes in the skeletal spine, especially the compression of
vertebral bodies, are characterized in the MR image by an increased T2 signal of the bone marrow
corresponding to edema, which can also be used to estimate the age of the fracture. A certain
limitation of MR can sometimes be difficulties in detection of skeletal fractures, which are
generally better visible on CT.


Non-traumatic conditions

Back pain, especially in the lumbar region, is a very common clinical problem, which is one of the
most common reasons for visiting a doctor. In most cases, non-traumatic back pain has no obvious
cause and usually resolves spontaneously within a few weeks, sometimes referred to as non-specific
back pain. In this case, the international guidelines generally oppose the routine use of imaging
methods, which do not provide any essential information necessary for the treatment, which usually
consists of symptomatic analgesic therapy. However, it is not a mistake to take an X-ray of the
spine.

In patients with back pain, however, it is necessary to take into account so-called " red flags ",
i.e. significant clinical circumstances that may indicate a more serious structural pathology of
the spine as a cause of back pain. These include, in particular, known or suspected oncological
diseases (weight loss, etc.), long-term use of corticosteroids or other conditions leading to
osteoporosis, signs of infectious disease or immunodeficiency, etc. In such cases, X-ray
examination of the spine especially compression of vertebral bodies. If the problem persists or if
there is a serious clinical suspicion of structural pathology of the spine, MR is the method of
choice, which, in addition to assessing the severity of degenerative changes, allows to detect
pathological changes of the bone marrow of the spine with sensitivity exceeding not only X-ray but
also CT examination. CT, unlike MR, rather than bone marrow involvement, detects the destruction of
the mineralized component of bone, which in many cases occurs in the later stages of the disease;
therefore, the indication for CT examination of the spine is currently reserved almost exclusively
for traumatic conditions. On MR, we can detect, for example, metastatic or inflammatory involvement
of the spine in patients with back pain. In the case of metastases or other tumorous process of the
skeletal spine, MR enables sensitive detection of skeletal infiltration (Fig. 3), eventually the
spread of the soft tissue component of the tumor paravertebrally or into the spinal canal.


The most common inflammatory diseases of the spine include spondylodiscitis, which is an infectious
process affecting the intervertebral disc and adjacent parts of the vertebral bodies. The optimal
imaging method for the detection of spondylodiscitis is MR, which allows to detect inflammatory
changes from the early stage of inflammation in the form of edema or pathological enhancement of
the intervertebral disc and adjacent parts of vertebral bodies (Fig. 4) . In these cases, where
skeletal destruction is not yet present, X-ray and CT examination are not very sensitive. Methods
of nuclear medicine (bone scintigraphy, PET) also have a high sensitivity for the detection of
spinal inflammation, although the findings, especially in the case of bone scintigraphy, are less
specific compared to MR.


In patients with back pain, in addition to the anamnesis and basic physical examination, it is also
appropriate to perform a neurological examination to detect radiculopathy or other neurological
symptoms. In such cases, MR examination is indicated. MR enables precise visualisation of possible
disc herniations and their relationship to nerve structures (Fig. 5).


Other causes of back pain

There are a number of diseases whose clinical picture is characterized by back pain and which can
therefore mimic vertebrogenic problems. These conditions include, for example, renal colic, acute
pancreatitis, and aortic dissection. Therefore, in the context of differential diagnosis, it is
necessary to look for clinical and laboratory signs that may raise suspicion of these diseases. In
such a case, there are indicated appropriate imaging methods targeted at specific anatomical areas,
most often ultrasound or CT.