Anomalous location of the vertebral artery in relation to the neural foramen. Implications for cervical transforaminal epidural steroid injections

Correlation Between Intravascular Injection Rate, Pain Intensity, and Degree of Cervical Neural Foraminal Stenosis During a Cervical Transforaminal Epidural Block

Purpose

Cervical transforaminal epidural blocks (CTEBs) are useful for the treatment of cervical radicular pain. However, during CTEBs, inadvertent intravascular injection can introduce particulate steroids into the bloodstream, thus leading to serious complications. Moreover, the risk factors associated with intravascular injection during CTEBs have not been identified. Cervical neural foraminal stenosis (CNFS) is a form of neural foraminal narrowing and a common cause of cervical radicular pain. In this study, we aimed to identify whether there is a correlation between the incidence of intravascular injection during CTEB, pain intensity, and the degree of CNFS.

Patients and Methods

A total of 126 patients were recruited. The patients were classified into two subgroups (group M and group S) based on the routine cervical T2-weighted axial magnetic resonance imaging (MRI) findings. Group M (n = 63) consisted of moderate CNFS patients, while group S (n = 63) consisted of severe CNFS patients. The occurrence of intravascular injection during CTEB was established using real-time fluoroscopy. The intravascular injection was determined by the spreading of the contrast medium through the vascular channel during the injection. Additionally, pain intensity was scored using a Numeric Rating Scale (NRS) before the procedure and 1 month after the procedure.

Results

There was no significant difference in the incidence of intravascular injection during CTEB between group M and group S (41.3% vs 39.7%, respectively; p = 0.99) and in the NRS scores before and 1 month after CTEB. However, both groups showed a significant decrease in the NRS scores at 1 month after the procedure compared with that before the procedure.

Conclusion

The degree of CNFS does not affect the incidence of intravascular injection during CTEB. Regardless of whether patients have moderate or severe CNFS, caution should be exercised during CTEB procedures.

Incidence of Extravascular Perivertebral Artery Contrast Flow During Cervical Transforaminal Epidural Injections

Background

During a cervical transforaminal epidural injection, injectate flows along the path of least resistance. Given the proximity of the vertebral artery to the intervertebral foramen, injected contrast may flow along the external wall of the artery. The incidence of this contrast flow pattern during cervical transforaminal epidural injections is unknown.

Purpose

To determine the incidence of extravascular perivertebral artery contrast flow patterns during cervical transforaminal epidural injections.

Study Design/Setting

Retrospective, observational, in vivo study.

Patient Sample

Patients receiving cervical transforaminal epidural injections at a single outpatient spine clinic.

Outcome Measures

The presence or absence of extravascular perivertebral artery contrast flow.

Methods

The saved images from 100 consecutive patients were reviewed by two independent observers and classified with or without extravascular perivertebral artery contrast flow. The incidence was determined and kappa was used to examine inter-rater reliability. All disagreements were reviewed, and the final classification was determined by consensus.

Results

The inter-rater reliability was moderate, with a kappa value of 0.69. The incidence of extravascular perivertebral artery contrast flow patterns was 49% by consensus. No statistically significant differences in incidence were present when comparing three different final needle tip positions.

Conclusions

During a cervical transforaminal epidural injection, an extravascular perivertebral artery contrast flow pattern is frequently encountered. This includes flow along the exiting nerve and then around the vertebral artery, as suggested by this study. Although this contrast pattern does not represent an intravascular injection into the vertebral artery, practitioners should remain cautious to exclude intravascular needle placement before injecting medication.

Microanatomical considerations for safe uncinate removal during anterior cervical discectomy and fusion: 10-year experience

Cervical radiculopathy from uncovertebral joint (UVJ) hypertrophy and nerve root compression often occurs anterior and lateral within the cervical intervertebral foramen, presenting a challenge for complete decompression through anterior cervical approaches owing to the intimate association with the vertebral artery and associated venous plexus. Complete uncinatectomy during anterior cervical discectomy and fusion (ACDF) is a controversial topic, many surgeons relying on indirect nerve root decompression from restoration of disc space height. However, in cases of severe UVJ hypertrophy, indirect decompression does not adequately address the underlying pathophysiology of anterolateral foraminal stenosis. Previous reports in the literature have described techniques involving extensive dissection of the cervical transverse process and lateral uncinate process (UP) in order to identify the vertebral artery for safe removal of the UP. Recent anatomical investigations have detailed the microanatomical organization of the fibroligamentous complex surrounding the UP and neurovascular structures. The use of the natural planes formed from the encapsulation of these connective tissue layers provides a safe passage for lateral UP dissection during anterior cervical approaches. This can be performed from within the disc space during ACDF to avoid extensive lateral dissection. In this article, we present our 10-year experience using an anatomy-based microsurgical technique for safe and complete removal of the UP during ACDF for cervical radiculopathy caused by UVJ hypertrophy.

Cervical foraminal steroid injections under CT guidance: retrospective study of in situ contrast aspects in a serial of 248 cases

OBJECTIVES

To describe all the CT findings after in situ contrast injection just before steroid injection and to recognize the abnormal aspects associated with intravascular contamination.

MATERIAL AND METHODS

We retrospectively evaluated 248 cervical transforaminal steroid injections done at the university hospital in Dijon, France, in 2008-2012, to treat cervicobrachial neuralgia inadequately improved by optimal medical treatment for at least 3 weeks. Features describing the opacification patterns were recorded.

RESULTS

Five main nonvascular opacification patterns were identified: clumps of contrast agent outside the foramen (16 %), a crab claw pattern surrounding the ganglion (13 %), a "French" circumflex accent pattern (15 %), reflux along the needle (7 %), and facet joint capsule opacification (22 %). Concerning the situations requiring a change in needle position, intravenous injection occurred in 26 % of the patients, with a crab claw pattern in half the cases and a clump pattern in half the cases. Intraarteriolar injection was noted in two patients.

CONCLUSION

CT after in situ contrast injection ensures proper needle positioning outside the blood vessels before steroid injection. Penetration of the needle tip into a vein is very common, whereas arteriolar puncture is extremely rare.

Cervical radicular pain: the role of interlaminar and transforaminal epidural injections

Chronic neck pain and cervical radicular pain are relatively common in the adult population. Treatment for chronic radicular pain recalcitrant to conservative management includes surgical management as well as interventional techniques with epidural injections utilizing either an interlaminar approach or transforaminal approach. Although there have been multiple systematic reviews and randomized clinical trials of cervical interlaminar epidural injections, the literature is sparse in reference to cervical transforaminal epidural injections. Overall, there is good evidence for the effectiveness of cervical interlaminar epidural injections in managing cervical disc herniation and fair evidence in managing central spinal stenosis and postsurgery syndrome. The evidence is poor, however, for cervical transforaminal epidural injections. Complications with cervical interlaminar epidural injections are rare, but more commonly occur with transforaminal epidural injections and can be fatal. Emerging concepts in pain include further randomized trials; proper placebo design; focus on control design (either active control or placebo control); and appropriate methodologic quality assessment and evidence synthesis.

The effectiveness and risks of fluoroscopically guided cervical transforaminal injections of steroids: a systematic review with comprehensive analysis of the published data

OBJECTIVE

To determine the effectiveness and risks of fluoroscopically guided cervical transforaminal injection of corticosteroids in the treatment of radicular pain.

DESIGN

Systematic review of the literature with comprehensive analysis of the published data.

INTERVENTIONS

Three reviewers with formal training in evidence-based medicine searched the literature on fluoroscopically guided cervical transforaminal injection of steroids (CTFIS). Each reviewer independently assessed the methodology of studies found and appraised the quality of the evidence presented.

OUTCOME MEASURES

The primary outcome assessed was relief of radicular pain. Other outcomes such as reduction in surgery rate and complications were noted if reported. The evidence on each outcome was appraised in accordance with the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system of evaluating evidence.

RESULTS

The searches yielded 16 primary publications on effectiveness. Available evidence, derived mainly from observational studies, suggests that approximately 50% of patients experience 50% relief of radicular pain for at least 4 weeks after CTFIS, and the intervention may have surgery-sparing effects. The literature also contains 21 articles with primary reports of serious complications, including 13 deaths and many catastrophic neurological injuries. The evidence of pain-relieving effects, of surgery-sparing effects, and of risks of CTFIS were all rated as of very low quality according to the GRADE system.

CONCLUSIONS

In patients with cervical radicular pain, fluoroscopically guided CTFIS may be effective in easing pain and reducing need for surgery. However, the evidence of effectiveness is of very low quality, and the benefits of the procedure are compromised by the risks of serious complications.