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A Potentially Safer Approach To Fluoroscopically Guided Cervical Extraforaminal Nerve Blocks 2007

Interventional Spine

Louis A. Gilula, M.D.
Daniel Ma, M.D., B.S., Non ASSR Member

Scientific Paper

Purpose

Fluoroscopically guided extraforaminal selective cervical nerve blocks (SCNB's), require precise needle-tip positioning near the intervertebral foramen of interest. Improper placement diminishes the procedure's therapeutic and diagnostic potential while increasing the probability for complication [1]. Death [2] as well as other serious complications such as spinal cord infarction [2], injection into an anterior radicular artery [3], puncture of the epidural sac of the nerve root sleeve [4], and potential injury to the vertebral artery [5] have been reported during cervical nerve blocks. These complications are felt to result from intravascular passage of medication [6]. As such, standard imaging protocols involve frontal and oblique views for accurate needle-tip visualization [7]. However, the addition of a lateral view identifies anterior needle-tip displacement in relation to the articular pillars [1]. The purpose of this presentation is to describe the inadequacy of using only frontal and oblique views, to stress the use of a lateral view to verify the adequacy of needle tip placement, and to present an injection technique that we could not find previously reported that provides potential marked improvement in the safety of medication injection.

Methods & Materials

The patient is placed in a lateral position on the fluoroscopic table with the symptomatic side elevated. The patient is rotated to a slight off-lateral position to profile barely the intervertebral foramen of interest. As the posterior tubercle of the transverse process may project over the approach to the extraforaminal area, the tube or the Image Intensifier above the patient is angled from the feet toward the head to project the tubercle cephalad to the foramen. After sterile precautions, local anesthesia may or may not be performed directly external to the site through which the needle will be passed into the extraforaminal region. A 25 gauge 2 inch (3 1/2 inch in thick necked people or in lower levels as C8) needle with a 5 - 10° bend on the needle tip is placed so that the needle tip is along the anterior aspect of the articular pillar just below the facet joint at the level at which the nerve root is to be blocked. A short bend on the needle tip is made by bending the needle tip covered by a sterile 4 x 4 gauze between an index finger and thumb. The needle will be safely posterior to the vertebral artery if the needle is kept along the anterior surface of the articular pillar (lateral mass). The needle tip may be advanced to the mid-portion of the pillar on the frontal view to keep to the lateral side of the vertebral artery. For a foraminal epidural effect the needle tip can be passed carefully to the medial portion of the pillar under fluoroscopic control. C-arm fluoroscopy is effective to guide these injections. A second T.V. monitor with last image hold is very helpful for checking subtle changes in needle position and inadvertent vascular filling.

A short, lymphangiographic connecting tube [9] attached to a syringe with dense contrast is then press fit to the needle. Dense water-soluble contrast as used for myelography is injected to verify adequate needle tip position. When contrast flow is adequate and not passing into a blood vessel, the contrast syringe is replaced with a 3 cc syringe containing injectate. In the cervical spine, we inject 1/2 cc of 2% preservative-free Lidocaine with 1/2 cc of steroid, [Betamethasone (Celestone) or Depomedrol 40 mgs (1/2 cc of Depomedrol 80 mg/cc)] + 1/2 cc of contrast ( I prefer dense myelographic contrast) for a total volume of 1 1/2 cc. Adding contrast to the injectate allows one to see accurately where the medication mixture is passing. This approach also shows if inadvertent needle tip movement has caused intravascular communication. When selective nerve block is desired to identify which nerve is causing pain and there is no desire to try to treat the level, then the medication mixture is kept overlying the pillar, since injectate passing cephalad and/or caudal could affect more than one anatomic level. With a desire potentially to treat the patient as well as to perform a confirmatory diagnostic exam, medication mixture is placed to pass into the epidural space.

Results

This procedure injecting contrast with the final injectate has been used in 560 cervical spine extraforaminal and foraminal injections between 1-10-04 to 5-19-06 without serious complications. It is the firm belief of this presenter that only by using contrast mixed with the final injectate and intermittent fluoroscopy during injection, can the distribution of injectate be objectively monitored. Using CT guidance [10, 11] for cervical spine injections will not allow continual monitoring of injectate into rapidly flowing blood vessels. Inadvertent injection into an arterial structure is the reason some people believe that death has occurred rarely with cervical nerve blocks in the past. In addition, use of a short lymphangiographic tube during injection can limit needle tip movement during testing of correct needle tip position and final injection of injectate.

We have used myelographic type contrast mixed with steroids and anesthetic for several thousand injections over several years in various parts of the spine without any known complications from use of such mixtures.

Conclusion

A short connecting tube, contrast mixed with final injectate, and fluoroscopy allow continual monitoring of injectate including where washout of original testing contrast actually flows. A true lateral view shows a more dangerous anterior needle tip placement.

References

1. Ma D, Gilula LA, Riew KD. Complications of fluoroscopically guided extraforaminal cervical nerve blocks: An analysis of 1036 injections. J Bone Joint Surg Am. 2005; 87:1025-1030
2. Brouwers PJM, Kottnik ELBL, Simmon MAM, Prevo RL. A cervical anterior spinal artery syndrome after diagnostic blockade of the right C6-nerve root. Pain 2001; 91:397-399.
3. Baker R, Dreyfuss P, Mercer S, Bogduk N. Cervical transforaminal injections of corticosteroids into a radicular artery: a possible mechanism for spinal cord injury. Pain 2003; 103:211-215.
4. Manchikanti L: Neural blockade in cervical pain syndrome. Pain Physician 1999; 2:65-84.
5. Furman MB, Giovanniello MT, O'Brien E. Incidence of intravascular penetration in transforaminal cervical epidural steroid injections. Spine 2003; 28:21-25.
6. Aprill C, Rogers K. Cervical transforaminal injection of corticosteroids. International Spinal Injection Society Scientific Newsletter. 2003; 4:21-32.
7. Rogers K, Aprill C. Practice guidelines and protocols: cervical transforaminal injections. 1st International Spine Injection Society Meeting, Boston Meeting Syllabus, September 2001.
8. Derby R, Lee SH, et al. Complications following cervical epidural steroid injections by expert interventionalists in 2003. Pain Physician 2004; 7:445-449.
9. Palmer W. Personal communication: Radiology Department, Massachusetts General Hospital. Harvard University, September 2003.
10. Silbergleit R, Bharat M, et al. Imaging-guided injection techniques with fluoroscopy and CT for spinal pain management. Radiographics 2001; 21:927-939
11. Zinreid SJ, Murphy K. Invited commentary regarding article: Silbergeit R, Bharat M, et al. Imaging-guided injection techniques with fluoroscopy and CT for spinal pain management. Radiographics 200; 21:941-942

There are no financial relationships with this material which would allow financial gain from this presentation.