Retrospective study of lumbar CT-guided steroid injections performed in a University Hospital between January 2012 and June 2015.
The minimum follow-up was 3 months.
The procedure was performed in patients with low back pain refractory to standard medical therapy and Lumbar Spine Rehabilitation.
Efficacy was assessed at 1 and 3 months according to a semiquantitative scale as the pain response as a) total response,
b) partially c) no or d) worsening pain.
A comparative study of the efficacy and safety was performed,
regarding: a) underlying pathology,
b) approach of injection and c) the different types of steroids used.
Fisher's test and Chi2 and the SAS System for Windows V program 9.2.were used for statistical analysis
Procedure
1.-Thecnical details
Once the patient is elegible for the procedure the optimal approach is selected by agreement between the clinician and the radiologist regarding a) the patient´s symptomatology b) preliminary image findings and c) accesibility.
Approaches used were: a) posterior epidural Fig. 1 ,
b) lateral recess Fig. 2 ,
and c) foraminal Fig. 3.
To avoid complications an meticulous procedure has to be performed.
At our institution we use the following protocol
1.
Check the coagulation status.
Any patient under anticoagulant therapy should be discontinued as long as the risk - benefit ratio advise the realization of the injeccion Fig. 4 .
2.
Informed consent.
Material preparation Fig. 5
3.
The patient is placed in prone position on the CT table,
using cushions if necessary for patient comfort and lordosis rectification,
facilitating the interlaminar access Fig. 6 .
4.
A topogram of the lumbar spine and study with small box centered at pathology level with the help of topogram.
This is essential to rule out unexpected in patients without evidence of previous image findings (infection,
tumor,
fractures ...)
5.
Selection of reference for precise slices for entry level depending on pathology and patient anatomy. Place a marker on the patient's skin and sterilization of the field,
local anesthesia (1% lidocaine) and neddle introduction (22-23G) Fig. 7 .
6.
Check the correct path and angulation and complete the introduction until the selected target.
7.
Aspiration with an empty syringe in order to discard blood or CSF outflow Fig. 8 .
8.
Injection of 0.1 ml of iodinated contrast to check it´s proper distribution in the epidural space Fig. 9 .
9.
Slow injection of the medication,
if necesary lidocaine 1% (1ml) can be injected first to reduce the risk of pain Fig. 10
10.
Removing the needle,
regional compression and rest prone for 20mins.
2.-Risk and complications
Reported complications are rare including infection,
bleeding,
headache,
local discomfort ,
vasovagal,
lipodystrophy ,allergic reactions,
systemic corticosteroid effects,
transient increase in pain and medullary infarction.
Whenever the thecal sac is punctured it is advisable to discontinue the procedure,
rescheduling it after one week to avoid the potencial risk of arachnoiditis if intrathecal corticoids are administered Fig. 11 .