Intravascular injection in lumbar medial branch block: a prospective evaluation of 1433 injections.
BACKGROUND
The successful outcome and validity of lumbar medial branch block (MBB) are largely dependent on technique accuracy. Intravascular uptake of injectate causes a false-negative response to block and is associated with various possible complications. In the current study, we prospectively evaluated the incidence of, and the factors associated with, intravascular injection during block. In addition, we assessed the efficiencies of generally accepted safety measures, such as preinjection aspiration and intermittent fluoroscopy to avoid intravascular injections.


METHODS
We prospectively examined 1433 lumbar MBBs in 456 patients performed by seven physicians. Aspiration test, spot radiography, and contrast injection under real-time fluoroscopic visualization were performed sequentially without repositioning the needle. Incidences of blood flashback and the presence of intravascular contrast spread on spot radiographic images and during real-time fluoroscopy were checked. The factors studied for intravascular injection included physician experience, patient age and sex, needle gauge, and block spinal level.


RESULTS
No specific factors were found to affect the incidence of intravascular uptake during block. The overall incidence of intravascular uptake was 6.1% per nerve block (88/1433), and 30 of these were predicted by preinjection aspiration (sensitivity = 34.1%) and 52 by spot radiography (sensitivity = 59.1%).


CONCLUSIONS
The aspiration test with or without spot radiography frequently missed the intravascular uptake of contrast during lumbar MBBs. We strongly advocate the use of real-time fluoroscopy during contrast injection to increase diagnostic and therapeutic value and to avoid possible complications.
Lee
Chul Joong
CJ
Department of Anesthesiology and Pain Medicine, Samsung Seoul Hospital, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Kim
Yong Chul
YC
Shin
Jae Hyuck
JH
Nahm
Francis Sahngun
FS
Lee
Hyo Min
HM
Choi
Yun Suk
YS
Lee
Sang Chul
SC
Ko
Justin Sang
JS
Kim
Tae Hyeong
TH
Sim
Woo Seok
WS
Kim
Chung Su
CS
Cho
Hyun Sung
HS
D000700:Analgesics / Q000008:administration & dosage*; D002037:Bundle-Branch Block / Q000503:physiopathology*; D004562:Electrocardiography; D006801:Humans; D007278:Injections, Spinal / Q000379:methods*; D008137:Longitudinal Studies; D008161:Lumbosacral Region; D009407:Nerve Block; D010092:Oximetry; D010146:Pain / Q000188:drug therapy*
D000700:Analgesics