++
Identifying the specific pathology responsible for spinal pain
is often difficult. This is particularly true given the high incidence
of anatomic abnormalities in asymptomatic individuals, and the presence
of normal anatomy in some painful individuals, at least as demonstrated
on conventional imaging studies.1,2 The primary
purpose of diagnostic injections for chronic spinal pain is to identify
which anatomic structure of the spine is causing pain and what is
the pathologic disorder affecting it. Before performing these injections,
the clinical utility of making an anatomic diagnosis should be well established.
++
Whether or not it is important to make an anatomic diagnosis
in patients with spinal pain is a matter of some debate.3,4 While
some would argue that in the majority of patients, attempts at making
an anatomic diagnosis are contraindicated, others feel that at a
minimum, making a diagnosis will help patients to heal by providing
them with a clear understanding of their problem.5 The
most important reason to make an anatomic diagnosis, however, is
if there are treatments that can be directed toward specific pathology,
leading to good outcomes. Many patients with spinal pain can be
treated with interventional pain management procedures. The success
of these procedures may depend on an accurate anatomic diagnosis;
however, typically little harm will come to the patient if the procedure
fails. Traditionally, the indications for surgery have been felt to
be neurologic loss. Increasingly, however, surgery is being performed
for pain without neurologic loss, essentially becoming a pain management
procedure. Although surgery may help some patients with chronic
pain, the tissue injury that necessarily accompanies surgery may
potentially lead to devastating consequences. If surgery is being
considered for patients with chronic pain, an accurate diagnosis
is essential. In this chapter, we focus on the role of diagnostic
injections in presurgical decision making.
++
There are two types of spinal pain: radicular pain and axial
pain.6 Radicular pain results from mechanical compression
or chemical irritation of a nerve root, or both. Establishing an
anatomic diagnosis for patients with radicular pain is important,
as surgical treatments have excellent outcomes in well-selected
patients. The source of radicular pain, typically either a herniated
nucleus pulposus or spinal stenosis, can be definitively diagnosed
at surgery; therefore, there is a gold standard that can be used
to assess the validity of diagnostic studies. Consequently, the
ability of both clinical findings and imaging studies to diagnose
the site of pathology is well defined. A diagnostic injection may
be indicated when imaging studies suggest that more than one nerve
root may be responsible for a patient’s symptoms. In that
circumstance, a selective epidural injection may be useful.
++
In contrast to radicular pain, the relationship between spinal
pathology and axial pain is uncertain. There are a number of anatomic
structures that are potential sources of pain, including myofascial tissues,
synovial joints, and the intervertebral discs. Although discogenic
pain is felt by many to be ...