Ultrasound-guided Versus Combined Ultrasound and Fluoroscopy-guided Cervical Selective Nerve Root Block for Lower Cervical Radiculopathy: Non-inferiority Randomized Controlled Study

Description

This study will be conducted to evaluate immediate and long-term effectiveness, functional improvements, and safety of ultrasound (US)-guided selective cervical nerve root block compared with fluoroscopy-guided selective nerve root block.

Technique of ultrasound guided cervical selective nerve root block:

Basic monitoring with non-invasive arterial blood pressure, electrocardiogram and pulse oximetry will be applied before the procedure, an intravenous catheter (20 G) will be inserted in a peripheral line for crystalloid infusion. Patients will be positioned in the oblique supine decubitus position with head externally rotated at 30° to 40° away from the targeted area, the frontal cervical spine area from the clavicle to mandible was adequately disinfected with Betadine and an aseptic dressing was applied. The sternocleidomastoid muscle was first palpated from the posterior side to palpate the transverse process of the cervical spine.

A (7-12) MHz linear transducer of a US machine will be applied to the symptomatic side of the neck in the transverse plane. Initially, the cervical nerve roots will be identified on US by the shape of the transverse process. Unlike the transverse processes of the 3rd to 6th cervical spines, the transverse process of the 7th cervical spine has a rudimentary anterior tubercle and a prominent posterior tubercle. The C6 transverse process characterized by its sharp anterior tubercle. The C5 transverse process identified by the "two-humped camel" sign formed by anterior and posterior tubercles. Within the intertubercular groove of the corresponding transverse process, the nerve root of each cervical spinal level will be observed with hypoechoic texture. The targeted nerve root of each patient will be identified by moving the transducer cranially from the C7 transverse process as a reference point.

The optimal image of the nerve root, location of the radicular artery and surrounding vessels near the border of the nerve root were obtained through probe manipulation in the power and color Doppler modes After the targeted nerve root identified, a 60-mm, 23-G needle will be gently introduced toward the dorsal aspect of the nerve root under real-time US guidance. The needle will be inserted just lateral to the transducer and advanced, from postero-lateral to antero-medial, with an in-plane approach. The needle tip will be placed between the nerve root and posterior tubercle outside of the intervertebral foramen and approached close to the epineurium with care to avoid inadvertent injection to the vessel through locating the vessels around the nerve root with color Doppler. Then, 1 ml of 1% lidocaine will be injected, following which the patient monitored for the onset of clinical manifestations such as mid-neck and contralateral arm pain, metallic taste, dizziness, tachycardia, full-body paraesthesia, auditory changes, slurred speech, and motor ataxia for 1 to 2 minutes. On confirmation of the absence of abnormal findings and careful aspiration, 3 cc of the treatment drug composed of dexamethasone (10 mg) and 0.5% lidocaine, will be injected under real-time US guidance

Technique of combined ultrasound and fluoroscopy guided selective nerve root block:

With the patient's head externally rotated 30 to 40 degrees away from the targeted area in a supine position, the frontal cervical spine area from the clavicle to mandible was adequately disinfected with Betadine and an aseptic dressing was applied. The sternocleidomastoid muscle was first palpated from the posterior side to palpate the transverse process of the cervical spine. A probe was placed and a transverse scan image of the transverse process was obtained after locating the transverse process. The location of the 7th transverse process was confirmed by visualization of the adjacent transverse processes sonographically from the superior to inferior direction. Unlike the transverse processes of the 3rd to 6th cervical spines, the transverse process of the 7th cervical spine has a rudimentary anterior tubercle and a prominent posterior tubercle, a unique characteristic used to identify and differentiate the 7th transverse process.

The targeted transverse process was identified by slowly moving the probe in all directions with the 7th cervical spine transverse process as the reference point. The optimal image of the nerve root, the location of the radicular artery, and the surrounding vessels near the border of the nerve root were obtained through the probe manipulation. Next, a spine needle 22 G was inserted from the posterior to anterior direction, toward the nerve root and parallel to the probe. The needle end was placed on the dorsal side of the nerve by cautiously avoiding damage to the possible deep cervical artery near the insertion site and locating the area free of the radicular artery. First, 1 ml of the contrast media was injected. The antero-posterior images were obtained to confirm the distribution or spread pattern of the injected contrast media with C-arm fluoroscopy. The following steps were initiated after confirming for proper shadowed contrast of the nerve root and absence of intravascular injection of the contrast media. One millilitre of 1 % lidocaine was injected and monitored for the onset of clinical manifestations such as mid-neck and contralateral arm pain, metallic taste, dizziness, tachycardia, full body paraesthesia, auditory changes, slurred speech, and motor ataxia for 1-2 min. Three cc of the treatment drug, composed of dexamethasone (10 mg) and 0.5 % lidocaine will be injected after confirming the absence of abnormal findings. The procedure will be completed after obtaining the images of the wash out spot

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