Incidence of intravascular penetration in transforaminal lumbosacral epidural steroid injections

STUDY DESIGN: A prospective, observational, human, in vivo study. OBJECTIVES: To evaluate the incidence of vascular penetration during fluoroscopically guided, contrast-enhanced, transforaminal lumbar epidural steroid injections (ESIs) and determine whether a "flash" (blood in the needle hub) or aspiration of blood can be used to predict a vascular injection. SUMMARY OF BACKGROUND DATA: Incorrectly placed, intravascular lumbosacral spinal injections result in systemic medication flow that misses the desired target. No previous studies evaluate the incidence of vascular injections in transforaminal ESIs, nor the ability of flash to predict a vascular injection. METHODS: The incidence of flash or positive blood aspiration and the incidence of fluoroscopically confirmed vascular spread were prospectively observed in 670 patients treated with lumbosacral fluoroscopically guided transforaminal ESIs. Presence of a flash or positive aspiration was documented. Contrast was injected to determine whether the needle tip was intravascular. RESULTS: Seven hundred sixty-one transforaminal ESIs were included. The overall rate of intravascular injections was 11.2%. There was a statistically significant higher rate of intravascular injections (21.3%) noted with transforaminal ESIs performed at S1 (n = 178), compared with those at the lumbar levels (8.1%, n = 583). Using flash or positive blood aspirate to predict intravascular injections was 97.9% specific, but only 44.7% sensitive. CONCLUSIONS: There is a high incidence of intravascular injections in transforaminal ESIs that is significantly increased at S1. Using a flash or blood aspiration to predict an intravascular injection is not sensitive, and therefore a negative flash or aspiration is not reliable. Fluoroscopically guided procedures without contrast confirmation are instilling medications intravascularly and therefore not into the desired epidural location. This finding confirms the need for not only fluoroscopic guidance but also contrast injection instillation in lumbosacral transforaminal ESIs.     

Incidence of intravascular penetration in transforaminal cervical epidural steroid injections

STUDY DESIGN A prospective, observational, human, study was conducted. OBJECTIVES To evaluate the incidence of vascular penetration during fluoroscopically guided, contrast-enhanced transforaminal cervical epidural steroid injections, and to determine whether the observation of blood in the needle hub can be used to predict a vascular injection. SUMMARY OF BACKGROUND DATA Incorrectly placed intravascular cervical spinal injections result in medication flow systemically and not to the desired target. A recently published study demonstrates a high incidence of intravascular injections in transforaminal lumbosacral epidural injections. No studies so far have evaluated the incidence of vascular injections in transforaminal cervical epidural steroid injections, nor have they calculated the ability of observed blood in the needle hub to predict a vascular injection in the cervical spine.METHODS The incidence of fluoroscopically confirmed intravascular uptake of contrast was prospectively observed in 337 patients treated with cervical transforaminal epidural steroid injections. The ability of observed blood in the needle hub to predict intravascular injection was also investigated. For each subject, the injection level was chosen on the basis of the clinical scenario including history, physical examination, and review of imaging studies. Some patients had multilevel injections. Using fluoroscopic guidance, the authors placed a 25-gauge needle into the epidural space using a transforaminal approach according to accepted standard technique. Needle tip location was confirmed with biplanar imaging. The presence or absence of blood in the needle hub spontaneously ("flash") and after attempted aspiration by pulling back on the syringe's plunger was documented. Contrast then was injected under real-time fluoroscopy to determine whether the location of the needle tip was intravascular. The results were recorded in a prospective manner indicating the presence or absence of blood in the needle hub and whether a vascular pattern was noted with contrast injection, and these were correlated. Relevant epidemiologic data also were recorded. RESULTS The study included 504 transforaminal epidural steroid injections. The overall rate of fluoroscopically confirmed intravascular contrast injections was 19.4%. Use of observed blood in the needle hub to predict intravascular injections was 97% specific, but only 45.9% sensitive. There was no significant difference in intravascular rates related to age or gender. CONCLUSIONS As compared with a previous study of lumbosacral epidural steroid injections, there is an overall higher incidence of intravascular injections with cervical transforaminal epidural steroid injections. Use of observed blood in the needle hub to predict an intravascular injection is not sensitive, and therefore the absence of blood in the needle hub despite aspiration is not reliable. The reported sensitivity and specificity rates are similar to lumbar data. Fluoroscopically guided procedures without contrast confirmation instill medications intravascularly, and therefore not in the desired epidural location. This study confirms that there is a need not only for fluoroscopic guidance, but also for contrast instillation in cervical transforaminal epidural steroid injections.     

Incidence of simultaneous epidural and vascular injection during lumbosacral transforaminal epidural injections.

BACKGROUND CONTEXT: The incidence of vascular penetration during contrast confirmed fluoroscopically guided transforaminal lumbosacral epidural injections has been reported as 8.9% to 21.3% depending on the level of injection. Recently, intermittent fluoroscopy was shown to miss more than half of the vascular injections observed under live fluoroscopy. The number of misses increased when epidural and vascular contrast flow appeared simultaneously, even if the fluoroscopic image was taken during contrast injection. To date, no studies have documented the incidence of simultaneous epidural and vascular contrast injections. Also, most previous studies of vascular injections did not document use of live fluoroscopy during contrast injection, so the incidence of vascular injections may be higher than reported. PURPOSE: To determine the incidence of simultaneous epidural and vascular contrast injection during lumbosacral transforaminal epidural injections. STUDY DESIGN/SETTING: A prospective, observational, in vivo, study. PATIENT SAMPLE: Patients receiving lumbar transforaminal epidural injections at a university-based outpatient spine center. OUTCOME MEASURES: Incidence of epidural, vascular, and simultaneous epidural and vascular contrast patterns. METHODS: One interventional spine physician and three fellows under his direct supervision recorded contrast patterns observed during 191 fluoroscopically guided lumbosacral transforaminal epidural steroid injections with injection of contrast observed under live fluoroscopy. RESULTS: The incidence of simultaneous epidural and vascular injection during lumbosacral transforaminal epidural injections was 8.9%. The incidence of a vascular injection alone was 4.2%, for a total vascular injection incidence of 13.1%. Subjects with a simultaneous epidural and vascular injection who returned for repeat injection had a statistically significant chance of a repeat simultaneous epidural and vascular injection when the injection was done at the same location. Fluoroscopy time was significantly increased, an average of 8.8 seconds, when a vascular injection was identified. There was no statistically significant correlation between the incidence of simultaneous epidural and vascular injection with subjects' age, sex, level of injection, side of injection, needle gauge, or diagnosis. CONCLUSIONS: Simultaneous epidural and vascular injection is twice as likely to occur as vascular injection alone. Use of intermittent fluoroscopy can miss the transient appearance of the vascular component of these injections, giving the false impression of successful contrast placement. In light of these results, live fluoroscopy is recommended during contrast injection for confirmation of lumbosacral transforaminal epidural injections.     

Rates of lumbosacral transforaminal injections interpreted as intravascular: fluoroscopy alone or with digital subtraction

We investigated the rate of injections interpreted as intravascular during imaging of lumbosacral transforaminal epidural injections, using fluoroscopy alone or with digital subtraction. We evaluated 732 injections performed on 348 patients: 8.1% (59/732) and 10.5% (77/732) of injections were interpreted as intravascular during fluoroscopy and digital subtraction, respectively, p = 0.13. The odds ratio (95% CI) for interpreting injections as intravascular increased for both fluoroscopy and digital subtraction fluoroscopy, with: each year of age, 1.04 (1.01–1.07) and 1.03 (1.00–1.06), p = 0.011 and 0.024, respectively; sacral compared with lumbar injections, 10 (5–19) and 8 (5–15), p < 0.001 for both. The odds ratio for intravascular injection increased with three other variables during digital subtraction fluoroscopy: spinal stenosis, 5.1 (1.5–17.1), p = 0.009; failed back surgery syndrome, 4.3 (1.2–15.8), p = 0.025; compression fracture, 8.0 (1.6–39.4), p = 0.011.     

Influence of needle type on the incidence of intravascular injection during transforaminal epidural injections: a comparison of short-bevel and long-bevel needles

Background contextVascular penetration and injection of corticosteroids into a vessel during lumbosacral transforaminal epidural injection is a suspected cause of myelopathy. Blunt needles have been suggested to avoid vascular penetration, but they are difficult to navigate. Another alternative to the standard long-bevel sharp needles is the short-bevel needles. Some have postulated that short-bevel needles are the best option for high-risk spine injections because they maintain navigation characteristics while potentially reducing the risk of complications. To date, no studies have been performed to either confirm or refute this.PurposeThe purpose of this study was to determine if there is a difference in the incidence of vascular penetration during lumbosacral transforaminal epidural injections between short-bevel and long-bevel needles.Study design/settingThis is a prospective, observational, in vivo study.Patient sampleThe sample comprises patients receiving lumbosacral transforaminal epidural injections at a university-based outpatient spine center.Outcome measureThe outcome measure was the incidence of vascular contrast patterns observed under live fluoroscopy.MethodsOne interventional spine physician recorded contrast patterns observed during 158 fluoroscopically guided lumbosacral transforaminal epidural injections under live fluoroscopy using two different types of needle tips.ResultsVascular injections were observed in 22 of the 158 injections, for an overall incidence of 13.9%. The incidence of vascular injections in the short-bevel group was 15.6% (10/64) and in the long-bevel group was 12.8% (12/94). This difference was not statistically significant (p=.6447). A secondary analysis was performed to determine if the needle gauge influenced the incidence of vascular injections, and again, there were no statistical differences in the overall rates of vascular injection.ConclusionsIn comparison with long-bevel needles, short-bevel needles do not reduce the risk of inadvertent vascular injection in lumbosacral transforaminal epidural injections.     

Cerebellar herniation after cervical transforaminal epidural injection

OBJECTIVE: The purpose of this study is to inform readers of potential catastrophic complications associated with performing cervical transforaminal epidural steroid injections. CASE REPORT: A 31-year-old man presented to the pain clinic with a history of cervical radicular pain and right upper-extremity radicular symptoms. He was referred from the orthopedic spine clinic for evaluation for epidural steroid injection, having failed conservative treatment consisting of nonsteroidal anti-inflammatory drugs, muscle relaxants, oral steroids, and physical therapy. After undergoing a transforaminal epidural steroid injection at the right C8 nerve root, he developed a cerebellar infarct and brainstem herniation. He survived but has residual deficits of persistent diplopia on right lateral gaze and difficulties with short-term memory loss and concentration. CONCLUSIONS: Although transforaminal epidural steroid injections are an efficacious treatment for radicular syndromes, there can be catastrophic complications. In light of the growing body of similar case reports, further investigation is warranted to establish a safe protocol for the use of this modality.     

Incidence of intravascular uptake in lumbar spinal injection procedures

STUDY DESIGN: Multicenter, prospective, observational study. OBJECTIVES: To document the incidence of and factors associated with intravascular uptake during lumbar spinal injection procedures. SUMMARY OF BACKGROUND DATA: In prior reports, the incidence of inadvertent intravascular needle placement during contrast-enhanced, fluoroscopically guided lumbar spinal injection procedures has been incidentally noted to range from 6.4% to 9.2%. We present the first systematic prospective documentation of intravascular uptake of contrast dye during different types of lumbar injection procedures. METHODS: Fifteen interventional spine physicians in seven centers recorded data regarding intravascular uptake during 1219 contrast-enhanced, fluoroscopically guided lumbar spinal injection procedures. RESULTS: The overall incidence of intravascular uptake during lumbar spinal injection procedures as determined by contrast enhanced fluoroscopic observation is 8.5%. Caudal and transforaminal routes have the highest rates at 10.9% and 10.8%, respectively, followed by zygapophyseal joint (6.1%), sacroiliac joint (5.3%), and translaminar (1.9%) injections. Intravascular uptake is twice as likely to occur in those patients over rather than under 50 years of age. Preinjection aspiration failed to produce a flashback of blood in 74% of cases that proved to be intravascular upon injection of contrast dye. CONCLUSION: The incidence of intravascular uptake during lumbar spinal injection procedures is approximately 8.5%. The route of injection and the age of the patient greatly affect this rate. Absence of flashback of blood upon preinjection aspiration does not predict extravascular needle placement. Contrast-enhanced, fluoroscopic guidance is recommended when doing lumbar spinal injection procedures to prevent inadvertent intravascular uptake of injectate.     

Detection of intravascular injection of regional anaesthetics in children

Purpose

Detection of intravascular injection of local anaesthetic during placement of regional blocks in children by using epinephnne-induced tachycardia or hypertension may produce false positive and false negative findings. This study evaluates ECG changes as markers of intravascular injection of local anaesthetics with epinephnne, during placement of epidural blocks in children.

Methods

Observational study in a teaching hospital of all epidural anaesthetics administered to paediatnc patients dunng one year. General anaesthesia, where used, was not controlled. An ECG rhythm strip was recorded during test dose injection and analyzed for changes in rate, rhythm, and T-wave configuration.

Results

During the study penod, 742 paediatnc epidural blocks were administered. There were 644 caudal (284 without catheters). 97 lumbar, and one thoracic epidural anaesthetics. Satisfactory placement was achieved in 97.7% of patients. Intravascular injection was detected in 42 (5.6%) of epidural anaesthetics (3.8% and 6.7% of straight needle and catheter injections, respectively). Detection was by immediate aspiration of blood in six patients, and by heart rate increases > 10 bpm in 30. Five had heart rate decreases suggesting a baroreceptor response. Five had heart rate increases < 10 bpm that were possible responses to noxious stimuli. Of 30 patients with known intravascular injection and for whom ECG strips were available, 25 (83%) had T-wave amplitude increases > 25%. and 29 (97%) had ECG changes in T-wave or rhythm in response to the epinephrine injection. There were no false positives.

Conclusion

In order to reduce risks associated with epidural anaesthesia in children, epinephnne should be added to the local anaesthetic test dose, the ECG should be monitored continuously for changes in heart rate, rhythm, and T-wave amplitude. Epidural injections should be given in small increments.     

Utility of the anesthetic test dose to avoid catastrophic injury during cervical transforaminal epidural injections

Background context

Reports of serious complications from cervical transforaminal epidural corticosteroid injections often consider accidental intra-arterial injection the most likely mechanism of injury. As a result, many physicians have instituted methods to prevent intravascular injections. Routine use of the anesthetic test dose is one such method. The utility of the anesthetic test dose in this function has not been characterized in the current literature.

Purpose

The aim of this study was to determine the utility of injecting an anesthetic test dose before cervical transforaminal epidural corticosteroid injection and estimate the rate of false-negative intravascular contrast injection using live fluoroscopy and digital subtraction angiography (DSA).

Study design

Two-center retrospective study.

Patient sample

A consecutive cohort of men and women, ages of 23 to 83, who underwent cervical transforaminal epidural injection and received the anesthetic test dose after contrast injection was negative for vascular uptake, observed using live fluoroscopy or DSA.

Outcome measures

Response to the anesthetic test dose was documented in each procedure note and recorded as either positive or negative.

Methods

Records of three physiatrists at two academic spine centers (Center A and Center B) were reviewed to identify all patients who received a cervical transforaminal epidural injection during the preceding 5 years, resulting in a cohort of consecutively treated patients at each center. Each patient record was reviewed for demographics, indication for injection, procedure level and side, needle gauge, use of DSA, volume and type of anesthetic test dose used, and result of test dose injection. The test dose was considered positive if the following occurred: agitation or other sudden central nervous system change; gross motor deficits and/or paresthesias in the trunk, legs, or contralateral arm; systemic symptoms of anesthetic toxicity including cardiac arrhythmia, perioral numbness, metallic taste, dizziness, and/or ringing in the ear. For analysis, injections were separated into groups to compare results at Center A to Center B and to compare injections that used DSA to those that did not. The incidence of a positive response was calculated as a percentage from the total number of injections in the group. Differences between groups were analyzed for statistical significance using the Fisher exact test.

Results

Six hundred seventy-eight injections were included. Of these, 349 were performed at Center A with test doses given after contrast injection under live fluoroscopy. The remaining 329 were performed at Center B, 183 also using live fluoroscopy, and 146 using DSA. The overall incidence of a positive anesthetic test dose was 0.59% (4/678). There was no significant difference between the incidence at each of the two centers (0.86% [3/349] vs. 0.30% [1/329]; p=.63). The overall incidence after live fluoroscopy was 0.75% (4/532) and after DSA was 0% (0/146), but this difference was not statistically significant (p=.58). Positive symptoms elicited by test dose administration included midneck and contralateral arm pain, metallic taste, dizziness, tachycardia, full body paresthesias, auditory changes, slurred speech, and motor ataxia. In all four cases with a positive response, the procedure was immediately terminated, symptoms resolved, and no lasting complications were observed.

Conclusions

The routine use of an anesthetic test dose appears to be safe and capable of detecting potentially dangerous intravascular injections undetected by conventional techniques. Positive responses occur in a small portion of those who receive the test dose injection. Further studies are required to determine the optimal dose and concentration of anesthetic to be used and the time required for observation after test dose administration.     

Transforaminal injection of autologous platelet-rich plasma for lumbar disc herniation: A single-center prospective study in Vietnam

ObjectiveLumbar radiculopathy is a major health problem, which often treated by neurosurgery or guided lumbar epidural steroids for pain relief. We used autologous Platelet Rich Plasma (PRP) as a novel pharmaceutical agent that has strongly emerged in recent years to treat patients of lumbar disc herniation. From that, we evaluated the efficacy of PRP via transforaminal route in treatment of radicular pain in patients with lumbar disc herniation.MethodsTwenty-five patients were enrolled and injected with 4 ml of autologous platelet rich plasma under fluoroscopic guidance via transforaminal epidural injection into area of affected nerve root. They were followed using Visual Analogue Scale (VAS), Modified Oswestry Disability Index (ODI) and Straight Leg Raising Test (SLRT) for clinical assessment.ResultsPatients who received transforaminal injections with autologous PRP showed statistically significant improvements on all three evaluation tools (VAS, ODI, SLRT). The improvements were sustained over twelve-month follow-up and there were no associated complications.ConclusionTransforaminal injection with autologous PRP helps patients relieve chronic pains and be able return to work. Besides, autologous PRP can be considered as a good alternative to epidural steroids in management of lumbar disc herniation.     

Treatment of lateral epicondilitis using three different local injection modalities: a randomized prospective clinical trial

Background  To determine the effectiveness of three different local injection modalities in the treatment of lateral epicondilitis. Methods  In a prospective randomized study on lateral epicondilitis, 75 patients were divided into three equal groups A, B and C (n = 25) and were treated using three different method of local injection. The patients in group A were treated with local injection of a steroid (1 mL triamcinolone) combined with local anaesthetic (1 mL lidocaine), those in group B were treated with injection of local anaesthetic (1 mL lidocaine) combined with peppering technique and those in group C with local injection of a steroid (1 mL triamcinolone) combined with local anaesthetic (1 mL lidocaine) and peppering technique. The outcome was defined by measuring the elbow pain during the activity using a 10-cm visual analogue scale (VAS) and satisfaction with the treatment using a scoring system based on the criteria of the Verhaar et al. at 3 weeks and 6 months after the injection and compared with the pre-treatment condition. Results  There were significant (P = 0.006) differences in the successful outcomes between the three groups at 6 months. In group C in which local steroid + peppering injection technique were used; excellent results were obtained in 84% of patients comparing to 36% and 48% for patients in groups A and B, respectively. The successful outcomes were statistically higher in group C comparing to group A (P = 0.002) and group B (P = 0.011). In all groups, there was a significantly lower pain (VAS) at the 3-week and 6-month follow-ups comparing to the pre-treatment condition. VAS measured at 6-month follow-up were significantly lower in group C comparing to other groups (P = 0.002). Conclusion  In the treatment of lateral epicondilitis, combination of corticosteroid injections with peppering is more effective than corticosteroid injections or peppering injections alone and produces better clinical results.     

Reversible posterior leukoencephalopathy syndrome after cervical transforaminal epidural steroid injection presenting as transient blindness

Transforaminal epidural steroid injections have been introduced as a nonsurgical treatment for cervical pain syndromes; however, they have also raised safety concerns. We present a patient who developed a headache and bilateral visual disturbance after cervical transforaminal epidural steroid injections. Brain magnetic resonance imaging showed a high signal intensity in the posterior region on T2-weighted and fluid-attenuated inversion recovery images, and the findings of diffusion-weighted imaging and the apparent diffusion coefficient map suggested vasogenic edema. The symptoms and abnormal imaging findings disappeared during follow-up. The clinical and imaging characteristics and their complete reversibility corresponded to reversible posterior leukoencephalopathy syndrome.     

An injection from the past: fluoroscopic evidence of remote injections of radiopaque substances

OBJECTIVE: Although uncommon, residual effects from contrast agents used more than 2 decades ago are possible. This case report is to alert clinicians to the implications of residual oil-based ionic contrast agents in the intrathecal space. CASE REPORT: A 70-year-old female with evidence of degenerative disc disease underwent a series of lumbar epidural steroid injections. Fluoroscopy during the procedure revealed diffuse residual intrathecal iophendylate (Pantopaque) dye. We were able to demonstrate unrestricted epidural spread of 1 mL iohexol (Omnipaque 180) alongside the preexisting dye. CONCLUSIONS: The goal of this case report is to highlight the potential of residual myelographic dye to complicate interventional procedures. Such residual dye can increase the level of difficulty in performing interventional pain treatments and perhaps the rate of complications associated with epidural injections, such as dural puncture. The presence of large amounts of residual oil-based intrathecal dye can lead to erroneous interpretations of the dye patterns as intraspinal lipoma or hemorrhage. As a consequence, the patient can be submitted to unnecessary diagnostic and therapeutic interventions. In addition, concerns of worsening oil-based dye-induced arachnoiditis with the use of epidural steroid injections can complicate the treatment of patients with back pain.     

Outcomes of interlaminar and transforminal spinal injections

Epidural spinal injections can be administered via a translaminar or transforaminal route, depending on the clinical scenario. When it is more desirable to target a specific nerve root, a transforaminal approach is typically used, and when the target is more diffuse, a translaminar method is chosen. Both are commonly used and can be utilized similarly in the lumbar or cervical spine. However, it is essential that the clinician understand the risks and benefits of these injections. In the lumbar spine, both translaminar epidural steroid injections (TLESI) and transforaminal epidural steroid injections (TFESI) have been shown to provide up to 6 months of pain relief, though long-term benefits are less reliable. In the cervical spine, translaminar injections may provide longer relief and have a lower complication rate than cervical transforaminal injections. Proper technique is essential to minimize the rate of these rare but occasionally severe complications.     

The flow patterns of caudal epidural in upper lumbar spinal pathology

Epidural steroid injections are an important therapeutic modality employed by spinal surgeons in the treatment of patients with chronic low back pain with or without lumbar radiculopathy. The caudal epidural is a commonly used and well-established technique; however, little is known about the segmental level of pathology that may be addressed by this intervention. This prospective study of over 50 patients aimed to examine the spreading pattern of this technique using epidurography. The effect of variation in Trendelenburg tilt and the eradication of lumbar lordosis on the cephalic distribution of the injectate were investigated. 52 patients with low back pain and radiculopathy underwent caudal epidural. All had 20 ml volume injected, comprised of 5 ml contrast (Ultravist™ Schering) 2 ml Triamcinolone (Adcortyl™ Squibb) and 13 ml local anaesthetic (1% lignocaine). Patients were randomised to either 0° or 30° of Trendelenburg tilt, as referenced from the lumbar spine. Patients were further randomised to presence or absence of lumbar lordosis, which was eradicated using a flexion device placed beneath the prone patient. A lateral image of each sacrum was obtained, to identify variations in sacral geometry particularly resistant to cephalic spread of injectate. The highest segment reached on fluoroscopy was recorded post injection. Fifty-two patients with a mean age of 50 years underwent caudal epidural. Thirty-one were in 0° head tilt, with 21 in 30° of head tilt. In each of these groups, 50% had their lumbar lordosis flattened prior to caudal injection. The median segmental level reached was L3, with a range from T9 to L5. Eradication of lumbar lordosis did not significantly alter cephalic spread of injectate. There was a trend for 30° tilt to extend the upper level reached by caudal injection (p = 0.08). There were no adverse events in this series. Caudal epidural is a reliable and relatively safe procedure for the treatment of low back pain. Pathology at L3/4 and L4/5 and L5/S1 can be approached by this technique. Although in selected cases thoracic and high lumbar levels can be reached, this is variable. If pathology at levels above L3 needs to be addressed, we propose a 30° head tilt may improve cephalic drug delivery. The caudal route is best reserved for pathology below L3.     

Paralysis after transforaminal epidural injection and previous spinal surgery

OBJECTIVE: This case discusses a rare but devastating complication of transforaminal epidural injection. Elements in the patient's history that may be risk factors are discussed. CASE REPORT: A 64-year-old man was evaluated for chronic low-back pain after multiple spine surgeries. After the most recent surgery, he suffered transient cauda equina symptoms. Because conservative therapy was not helpful for spinal stenosis and neuroclaudication, a left L2 transforaminal epidural injection was attempted, but a posterolateral fusion mass made this procedure impossible. A left L1 transforaminal approach was successful, and 1 mL of iopamidol (Isovue) contrast was injected, followed by 5 mL of a solution of 0.125% bupivacaine and 40 mg of triamcinolone. Approximately 1 to 2 minutes after injection, the patient described discomfort in the lower abdomen, and 1 minute later, he was unable to move his lower extremities. An MRI showed T2 signal change in the conus medullaris gray matter at T11-12, consistent with an acute vascular infarct. Spinal shock protocol with high-dose methylprednisolone was begun without change. More than 4 years later, the patient continues to be troubled by persistent paraparesis and chronic pain. CONCLUSIONS: This case report is part of a new and growing body of literature that demonstrates the potential risk of transforaminal injection. Further study is necessary to ensure that spinal vascular injuries can be kept to an acceptably rare level.     

Inadvertent subdural spread complicating cervical epidural steroid injection with local anaesthetic agent

Although cervical epidural steroid injection with local anaesthetic is considered a safe technique and widely practiced, complications may occur. We report a patient experiencing unexpected delayed high block, moderate hypotension and unconsciousness eight to ten minutes after an apparently normal cervical epidural steroid injection. The most probable diagnosis was a subdural block. Anatomical peculiarities of the epidural and subdural space in the cervical region increase the risk of subdural spread during cervical epidural injection. Fluoroscopic guidance is important during cervical epidural injection to increase certainty of correct needle placement, thus minimizing the risk of complications.     

经椎问孔硬膜外注射后血管内显影：颈椎和腰椎节段的对比研究

背景经椎间孔硬膜外注射（transforaminalepiduralinjection,TEI）常用于治疗神经根性疼痛。然而,许多已发表的研究表明,TEI后可有严重并发症,且多发生在颈椎段水平;对该并发症的一种解释是操作者不慎将药物误注射入血管内。本研究的目的在于鉴别TEI时颈椎段和腰椎段血管内注射的发生率。方法将伴有神经根性疼痛症状或者带状疱疹相关性疼痛的患者前瞻性地分为2组,由作者中的一位对其实施颈椎段或腰椎段TEI。以双平面X线透视确认穿刺针的理想位置后,操作者在实时显影的X线透视下,以0．3—0．5ml／s的速度持续注入非离子型造影剂和生理盐水混合液3ml。结果共实施了182例TEI,其中56例（30．8％）出现了血管内显影,45例发生在颈椎段TEI（cervicalTEIs,CTEIs）,11例发生在腰椎段TEI（1umbarTEIs,LTEIs）。出现神经周围和血管内同时显影的发生率分别是：CTE[s52．1％、LTEIs9％,仅出现血管内显影的比例是：CTEIs11．3％、LTEIs0．9％。结论佃s血管内注射的发生率明显高于LTEIs,提示实施CTEIs时应更加谨慎。此外,CTEIs时血管内注射的发生率高于已有的文献报道,这个发现提示检测TEI血管内注射时,选用适宜容量的造影剂（3ml）是必要的,尤其是在同时出现神经周围和血管内显影时。     

Approaches in injections for radicular pain: The transforaminal, epidural and transfacet approaches

Spinal injections must be carried out adhering to very strict conditions. However, these procedures have almost come to be seen as everyday and may be practised under quite questionable conditions. The recent reports of new and extremely serious neurological complications have changed the attitudes of those making referrals as well as the attitudes of the interventional radiologists carrying out these procedures. The range of indications for transforaminal injections has shrunk in favour of epidural injections. Where the transforaminal approach is still used, the needle must be positioned extremely accurately. A prior radioopaque contrast medium injection is essential from a safety perspective. The transforaminal epidural injection via the transfacet approach looks to be a promising alternative that is strictly avascular.     

Paravertebral somatic nerve block: a clinical, radiographic, and computed tomographic study in chronic pain patients

The spread of solution after a standardized paravertebral injection was studied to determine the precision and predictability of paravertebral spread. The spread of 5 ml of a solution of radiological contrast medium (sodium iothalamate) and local anesthetic mixture after 45 (34 thoracic, 11 lumbar) paravertebral injections was studied in 31 patients by radiography and computed tomography and correlated with the clinical effects. Spread confined to the paravertebral area occurred after only eight (18%) injections. Spread was epidural after 31 (70%) injections and exclusively so in 14 (31%) injections. Mean sensory loss was greater after epidural spread, but a wide range of sensation loss was observed with all patterns of spread. Intrapleural spread occurred after three injections, as did spread into the psoas muscle. In addition, measurements were made of 114 paravertebral spaces in 20 patients by means of computed tomography. Dimensional factors identified as possibly leading to complications of a paravertebral injection included narrow width of the thoracic transverse processes (mean, 3.18 cm; range, 2.1-4.2 cm) and the wide range in paravertebral dimensions. The distance from bony landmarks to pleura frequently fell outside the limits recommended by many standard texts. We conclude that the spread of a small volume of solution after paravertebral injection is imprecise and unpredictable. Neurolytic and diagnostic paravertebral injections performed without the aid of radiological imaging and contrast media should be regarded as hazardous and interpreted with extreme caution.