Cervical medial branch block: a novel technique using ultrasound guidance.
BACKGROUND
Cervical medial branch blocks are commonly performed for the diagnosis and treatment of head, neck, and shoulder pain. Intermittent fluoroscopy is widely used for needle positioning and visualization of contrast distribution before medication injection. The purpose of this study was to examine the use of ultrasound as an alternative imaging technique to block the third occipital nerve and the C3 to C6 medial branches.


METHODS
The study involved 2 phases with a total of 53 patients. The purpose of phase 1 was to assess the reliability of needle positioning using an ultrasound target corresponding to the middle of the bony contour of the articular pillar. Twenty patients undergoing 46 cervical medial branch blocks between C3 and C6 were recruited, and the needle tip position was graded on a 3-point scale based on its proximity to the centroid on lateral radiograph. In phase 2, 50 patients undergoing 163 levels were recruited. Using ultrasound guidance, each of the targeted levels was injected with 0.3 mL of a 1:1 mixture of local anesthetic and contrast agent. A blinded assessor reviewed contrast distribution in the anteroposterior and lateral radiograph views.


RESULTS
In phase 1, all needle tips were positioned on the articular pillars; furthermore, 80.1% were located in the middle 2 quarters of the latter. In phase 2, the contrast was found to cover the appropriate level in 94.5% of cases, and no complications were noted. The incidence of aberrant spread to adjacent levels (13.5%) was similar to that reported with fluoroscopy.


CONCLUSIONS
Ultrasound guidance offers a reliable alternative to fluoroscopy for third occipital nerve and C3-C6 cervical medial branch blocks. Further studies are required to validate the clinical efficacy of our technique.
Montreal General Hospital, Department of Anesthesia, McGill University, Montreal, Quebec, Canada. roderick.finlayson@mac.com
Roderick J
RJ
Finlayson
Gaurav
G
Gupta
Mohammed
M
Alhujairi
Shubada
S
Dugani
De Q H
DQ
Tran
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000295:instrumentation / Q000379:methods*; D011446:Prospective Studies; D013127:Spinal Nerves / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*