Ultrasound-guided lumbar medial branch blocks and intra-articular facet joint injections: a systematic review and meta-analysis

Abstract

There is great interest in expanding the use of ultrasound (US), but new challenges exist with its application to lumbar facet-targeted procedures. The primary aim of this systematic review and meta-analysis was to determine the risk of incorrect needle placement associated with US-guided lumbar medial branch blocks (MBB) and facet joint injections (FJI) as confirmed by fluoroscopy or computerized tomography (CT). An a priori protocol was registered, and a database search was conducted. Inclusion criteria included all study types. Risk of bias was assessed using the Cochrane risk of bias tool for randomized controlled trials and the National Heart, Lung, and Blood tool for assessing risk bias for observational cohort studies. Pooled analysis of the risk difference (RD) of incorrect needle placement was calculated. Pooled analysis of 7 studies demonstrated an 11% RD (P , 0.0009) of incorrect needle placement for US-guided MBB confirmed using fluoroscopy with and without contrast. Pooled analysis of 3 studies demonstrated a 13% RD (P , 0.0001) of incorrect needle placement for US-guided FJI confirmed using CT. The time to complete a single-level MBB ranged from 2.6 to 5.0 minutes. The certainty of evidence was low to very low. Ultrasound-guided lumbar MBB and FJI are associated with a significant risk of incorrect needle placement when confirmed by fluoroscopy or CT. The technical limitations of US and individual patient factors could contribute to the risk of incorrect needle placement.

Accuracy of Ultrasound-Guided Needle Placement on the L5 Lumbar Nerve Root

“…Nevertheless, the technical limitations of ultrasound, the tissue depth of lumbar nerve roots and individual patient characteristics could determine the precision of ultrasound-guided procedures in the lumbar spine. 3 These results support that other guidance techniques would be required to properly reach L5 nerve root if not being visualized clearly with ultrasound.…”

“…For these reasons, efforts are being made to increase the use of ultrasound guidance for several procedures in the lumbar spine. 3 Nevertheless, there are concerns about its validity because the ultrasound-guided approach to vertebral structures of the lumbar spine can be difficult because of its three-dimensional complex anatomy, with high acoustic impedance of vertebral references. 10 In addition, the presence of anatomical variations such as a lumbosacral transitional vertebra is estimated to be present in 4%-30% of the population.…”

“…Minimally invasive techniques for managing low back pain are receiving increasing attention due to their potential advantages. These techniques include procedures such as facet joint nerve block, nerve root block, epidural block, lumbar transforaminal epidural steroid injections, sacroiliac joint blocks, and intra-articular facet injections 3 . However, clinical guidelines conclude that their effectiveness depends on the accuracy in reaching the targeted structure, requiring their visualization in real time 2 …”

“…In addition, ultrasound devices are affordable; several can be easily transported, and, more importantly, they avoid the ionizing radiation that occurs with fluoroscopy or computed tomography. For these reasons, efforts are being made to increase the use of ultrasound guidance for several procedures in the lumbar spine 3 . Nevertheless, there are concerns about its validity because the ultrasound-guided approach to vertebral structures of the lumbar spine can be difficult because of its three-dimensional complex anatomy, with high acoustic impedance of vertebral references 10…”

“…These techniques include procedures such as facet joint nerve block, nerve root block, epidural block, lumbar transforaminal epidural steroid injections, sacroiliac joint blocks, and intra-articular facet injections. 3 However, clinical guidelines conclude that their effectiveness depends on the accuracy in reaching the targeted structure, requiring their visualization in real time. 2 The American Society of Regional Anesthesia and Pain Medicine recognizes that the leading cause of failure of invasive block techniques and the occurrence of complications (such as nerve injury) is incorrect needle placement.…”