Fluoroscopy-Guided Sacroiliac Joint Injection:
Description of a Modified Technique
Authors: Kasliwal Prasad Jaychand 
Published: February 2021

Sacroiliac joint (SIJ) pathology is a common etiologic cause for 10 – 27% of cases of mechanical
low back pain (LBP) below the L5 level. In the absence of definite clinical or radiologic diagnostic
criteria, controlled blocks of the SIJ have become the choice assessment method for making
the diagnosis of SIJ pain. The SI joint is most often characterized as a large, auricular-shaped,
diarthrodial synovial joint. In reality, its synovial characteristic is limited only to the distal third
and anterior third. In SIJ interventions, the lateral view has been underutilized. In our technique,
we used the lateral view to create a three-dimensional view of the SIJ to aid in gauging the
accurateness of the contrast spread and to obtain a precise block. After obtaining appropriate
fluoroscopic images, a curved tip spinal needle was directed into the inferior aspect of the
SIJ using a posterior approach. As the needle contacts firm tissues on the posterior aspect of
the joint, position of the needle tip is checked using lateral fluoroscopy. In the lateral view,
the needle tip position is manipulated to keep it in the anterior third of the SIJ and contrast
is injected. Our criteria for accurate SIJ block, in posteroanterior (PA) view, is the injection
of the contrast medium should outline the joint space and the contrast medium should be
seen to travel cephalad along the joint line. In the lateral view, the contrast medium most
densely outlines the parameter of the joint. We have utilized this method with good effect in
approximately 30 cases over one year. Out of 30 cases, needle position and contrast spread
was satisfactory in 28 and 27 cases, respectively. So satisfactory needle placement and contrast
spread was in 93% and 87% cases. Pain relief of 80% or more after intra-articular injection of
local anaesthetic was seen in 50% (15 of 30) patients; pain relief of 50 – 79% was witnessed in
30% (9 of 30) patients. Thus, pain decreased 50% or more in 80% (24 of 30) of the joints. Out
of 24 joints where we got satisfactory needle position and contrast spread, 23 joints got more
than 50% relief. Thus, if needle position and contrast spread is satisfactory as per the criteria,
pain relief of 50% or more was in 96% (23 of 24) of joints. There are few possible limitations
with this study like difficulty to go up to the anterior third of the SIJ, it may be more painful as a
narrow joint line has to be travelled in depth, sciatic numbness due to drug leak, or injuring the
pelvic structure. Advantages of this method are that depth and level of the needle tip for a SIJ
block is described for the more precise block. This will reduce false positive and false negative
results, i.e., sensitivity and specificity of SIJ blocks and results for diagnostic blocks become
more reliable. It will also reduce the chances of a case getting abandoned due to inappropriate
contrast spread obscuring the fluoroscopic landmarks. As we know the depth of the needle, the
chances of injuring pelvic structures become less and safety improves.
Key words: Sacroiliac joint, low back pain, contrast dye, fluoroscopy, lateral view, pain
management, SI joint block, modified technique