Intravascular injection in cervical medial branch block: an evaluation of 361 injections

BACKGROUND: The prevalence of persistent neck pain, secondary to involvement of cervical facet or zygapophysial joints, has been described in controlled studies as varying from 39% to 67%. Cervical medial branch block (MBB) represents a useful interventional pain management procedure indicated in patients with a chronic neck pain of facet joint origin. 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 pre-injection aspiration and intermittent fluoroscopy to avoid intravascular injections. METHODS: We prospectively examined 361 cervical MBBs in 158 patients performed by 2 physicians. Aspiration test, spot radiography, and contrast injection under real-time fluoroscopic visualization were performed sequentially without repositioning the needle. Incidences of blood flash back 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 patient age and sex 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 3.3% per nerve block (12/361), and 7 of these were predicted by pre-injection aspiration (sensitivity = 58.3%) and 8 by spot radiography (sensitivity = 66.7%). CONCLUSIONS: The aspiration test with or without spot radiography frequently missed the intravascular uptake of contrast during cervical MBBs. We strongly advocate the use of real-time fluoroscopy during contrast injection to increase diagnostic and therapeutic value and to avoid possible complications.

Two Simple Tests for Adequate Needle Positioning in Vertebroplasty / 대한척추외과학회지

STUDY DESIGN: We analyzed the diagnostic values of two simple tests for adequate needle positioning in vertebroplasty. OBJECTIVES: We wanted to suggest performing the aspiration test and patency test, which can replace some of the roles of intraosseous venography (IOV) in vertebroplasty, and we also wanted to analyze the two tests' diagnostic values. SUMMARY OF LITERATURE REVIEW: Intra-osseous venography is an existing safety test for vertebroplasty, but it is less frequently performed nowadays because of its drawbacks. MATERIALS AND METHODS: The aspiration test is defined as positive if blood is easily aspirated through a vertebroplasty needle, and a positive aspiration test means that the needle tip is communicating with the venous system. This and IOV were carried out on a total of 114 sides of 61 vertebrae of 40 consecutive patients. Agreement between the two tests was evaluated with using Cohen's kappa coefficient, and the diagnostic values of the aspiration test, with using IOV as the gold standard, were also evaluated. The patency test is done in the intra-vertebral vacuum cleft cases. After bipedicular insertion of needles, saline is injected into one needle. If the saline gushes out of the other needle, the test is positive, and it means that both needles are inserted in the vacuum cleft. The patency test was performed in 25 vertebrae, and the positive rate and causes of the negative result were investigated. RESULTS: Cohen's kappa coefficient between the aspiration test and IOV was 0.88. The sensitivity of the aspiration test was 88%, the specificity was 99%, the positive predictive value was 97%, and the negative predictive value was 93%. The patency test was positive in 88% of the vacuum clefts. In all the positive cases, both needles were located within the vacuum cleft. In all the negative cases, one of the two needles was located outside the cleft. CONCLUSIONS: The aspiration test is a simple and reliable test that has high agreement with IOV. The patency test can be a better choice than IOV for the vacuum cleft cases because it does not leave contrast media in the clefts.