Caudal epidurals: the whoosh test

Analysis of caudal epidurogram in single center: A preliminary study of lumbar radiculopathy management

A caudal epidural block involves placing a needle through the sacral hiatus and delivering medication into the epidural space. The procedure is safe and simple, but failure rates can be as high as 25%. The purpose of this study was to investigate the success rate of caudal epidural block by analyzing needle placement and dye flow pattern.We retrospectively analyzed the medical records of patients who underwent caudal epidural block under spinal stenosis. A case was defined as a failure if it met at least one of the following four criteria: the epidural needle was not placed correctly inside the caudal canal; blood regurgitation or aspiration in the needle was observed; the contrast dye was injected into a blood vessel; or a large amount of the dye leaked into the sacral foramen or did not reach the L5-S1 level.At least 1 failure criterion was observed in 14 cases (17.7%), while none of the failure criteria were satisfied in 65 successful cases (82.3%).No matter how experienced the anesthesiologist may be, delivery of adequate therapeutic agent is not achieved in approximately 20% of cases. Therefore, we recommend fluoroscopy-guided needle placement and confirmation by radio-contrast epidurograpy as the best choice.

Caudal Epidural Block: An Updated Review of Anatomy and Techniques

Caudal epidural block is a commonly used technique for surgical anesthesia in children and chronic pain management in adults. It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space. Using conventional blind technique, the failure rate of caudal epidural block in adults is high even in experienced hands. This high failure rate could be attributed to anatomic variations that make locating sacral hiatus difficult. With the advent of fluoroscopy and ultrasound in guiding needle placement, the success rate of caudal epidural block has been markedly improved. Although fluoroscopy is still considered the gold standard when performing caudal epidural injection, ultrasonography has been demonstrated to be highly effective in accurately guiding the needle entering the caudal epidural space and produce comparative treatment outcome as fluoroscopy. Except intravascular and intrathecal injection, ultrasonography could be as effective as fluoroscopy in preventing complications during caudal epidural injection. The relevant anatomy and techniques in performing the caudal epidural block will be briefly reviewed in this article.

Caudal epidural steroid injection: a randomized controlled trial

Study design: Prospective study.

Study rationale: A recurrent phenomenon, the lifetime prevalence of low back pain has been reported as 54%–80%, while annual prevalence ranges from 15%–45%.1 It is also associated with enormous economic, societal, and health impact.2 India, being a developing country, has its problem compounded by the occupational compulsions in parts of the rural areas.3

For some interventional therapies, like epidural steroid injections, utilization rates have increased dramatically.4,5,6,7,8,9 They have become one of the most commonly performed interventions in the United States for low back pain with radiculopathy.10

Clinical question: Multiple systematic reviews,11 a meta-analysis,12 several guidelines,13 health technology assessments by insurers, and local medical review policies and coverage decisions have been published. However, controversy continues regarding the effectiveness of epidural steroid injections. In addition three types of epidurals, namely interlaminar, transforaminal, and caudal, with variable results complicate the picture for practice of interventional pain management. The underlying mechanism of action of epidurally administered steroid and local anesthetic injections is still not well understood and compounds the problem.14

Objective: To evaluate and update the effects of caudal epidural injection in the management of chronic low back pain and sciatica.

[Pediatric caudal anesthesia : importance and aspects of safety concerns]

Caudal block is a safe procedure commonly used for pediatric perioperative analgesia. Complications are extremely rare but nevertheless local and systemic contraindications must be excluded. Optimal safety and quality result when strict attention is paid to technical details. These are discussed in detail in this review. A local anesthetic (LA) containing epinephrine allows early detection of inadvertent intravascular LA administration; therefore an epinephrine/LA mixture is recommended at least for the test dose. In terms of safety the choice of LA itself is probably of secondary importance. Clonidine as an adjuvant has an excellent risk/benefit profile with minimal side effects. Inadvertent systemic LA intoxication is a rare but potentially fatal complication of regional anesthesia and measures for prevention and early detection are essential. Should circulatory arrest occur, immediate resuscitation following standard guidelines is to be initiated including the use of epinephrine as the first line drug. Intravenous administration of lipid solutions may be beneficial as a secondary adjunct to stabilize hemodynamics but is not an alternative to epinephrine.

[Pediatric caudal anesthesia: importance and aspects of safety concerns]

Caudal block is a safe procedure commonly used for pediatric perioperative analgesia. Complications are extremely rare but nevertheless local and systemic contraindications must be excluded. Optimal safety and quality result when strict attention is paid to technical details. A local anesthetic (LA) containing epinephrine allows early detection of inadvertent intravascular LA administration; therefore an epinephrine/LA mixture is recommended at least for the test dose. In terms of safety the choice of LA itself is probably of secondary importance. Clonidine as an adjuvant has an excellent risk/benefit profile with minimal side effects. Inadvertent systemic LA intoxication is a rare but potentially fatal complication of regional anesthesia and measures for prevention and early detection are essential. Should circulatory arrest occur, immediate resuscitation following standard guidelines is to be initiated including the use of epinephrine as the first line drug. Intravenous administration of lipid solutions may be beneficial as a secondary adjunct to stabilize hemodynamics but is not an alternative to epinephrine.

Caudal epidurals: the accuracy of blind needle placement and the value of a confirmatory epidurogram

The objective of this study was to assess the accuracy of blind placement of caudal epidural needles and the usefulness of the radio-contrast epidurogram. The study involves a prospective case series of 147 consecutive patients with radiological assessment of blind needle placement and epidurogram assessing the accuracy of blind needle placement in caudal epidurals. When the surgical miss rate (26%) and failure of flow of the therapeutic agents (6%) are combined, it can be deduced that up to 32% of non-radiologically guided caudal epidurals may fail to deliver the therapeutic agents to the site of pathology. There was no significant difference in the accuracy of needle placement in adequately trained and experienced middle grade surgeons when compared with consultant surgeons performing these procedures regularly. In conclusion, we recommend radiological guidance and use of epidurogram as the gold standard for the administration of caudal epidurals to increase the likelihood of successful delivery of the therapeutic agents to the site of pathology during the procedure.

Prospective, double-blind, randomized placebo-controlled trials in interventional spine: what the highest quality literature tells us

BACKGROUND CONTEXT

The prospective, double-blind, randomized, placebo-controlled study design is essential in the interventional spine literature to truly evaluate whether or not a procedure is effective.

PURPOSE

This article will critically evaluate the highest quality interventional spine literature with strict interpretation of the results of these trials.

STUDY DESIGN

Review article.

METHODS

Extensive Medline/Pubmed searches and searches of the large review articles on the major interventional spine topics were performed to find all prospective, double-blind, randomized placebo-controlled trials in the English language interventional spine literature.

RESULTS

Fluoroscopically-guided lumbosacral transforaminal epidural corticosteroid injections are effective in the treatment of acute/subacute lumbosacral radicular pain, and in preventing future surgeries. Injection of corticosteroid or Sarapin on the cervical or lumbar medical branch nerves is not effective. When done with proper technique, percutaneous radiofrequency lumbar and cervical medial branch neurotomy are both effective. Intraarticular sacroiliac joint corticosteroid injections are effective in patients with spondyloarthropathy. IDET is modestly effective in the treatment of lumbosacral discogenic pain in carefully selected patients. Percutaneous radio frequency neurotomy of the ramus communicans is effective in the treatment of lumbosacral discogenic pain. No firm conclusions can be drawn about cervical epidural corticosteroid injections, lumbosacral epidural corticosteroid injections for the treatment of chronic radicular pain, cervical or lumbosacral intraarticular zygapophysial joint corticosteroid injections for the treatment of degenerative zygapophysial joint pain, or intradiscal corticosteroid injections.

CONCLUSIONS

The prospective, double-blind, randomized placebo-controlled trials in the interventional spine literature demonstrate efficacy from several different procedures when properly performed on appropriate patients. Other procedures have been shown to lack efficacy, while inconclusive evidence exists from multiple other interventional spine procedures. Further details are discussed in the text.

Efficacy of steroid and nonsteroid caudal epidural injections for low back pain and sciatica: a prospective, randomized, double-blind clinical trial

STUDY DESIGN

Prospective, double-blind, randomized, case-control study.

OBJECTIVE

To evaluate the efficacy of caudal epidural injections (CEI) containing steroid versus nonsteroid preparations when treating patients suffering from low back pain (LBP) and sciatica.

SUMMARY OF BACKGROUND DATA

Literature seems to be deprived of well-designed randomized, controlled studies that evaluate the effectiveness of CEI in the treatment of chronic LBP; hence the value of CEI remains still the subject of controversy.

METHODS

Patients suffering from severe chronic LBP and sciatica were randomly allocated into 2 groups. Steroid-group's patients (n = 93) underwent CEI containing 12 mL of xylocaine 2% and 1 mL of betamethasone dipropionate and betamethasone phosphate (2 + 5) mg/dL. Water for Injection (WFI)-group's patients (n = 90) underwent CEI containing 12 mL of xylocaine 2% and 8 mL of WFI. Both groups were statistically comparable as far as their demographic data and the cause and duration of symptoms were concerned. Patients answered the Oswestry Disability Index questionnaire and underwent physical examination, before and at 1 week, 1 month, 6 months, and 1 year following the CEI.

RESULTS

Symptoms improved in 132 patients (72.1%) following CEI. The mean Oswestry Disability Index questionnaire score of steroid-group's patients was statistically significant lower than that of the WFI-group at all postinjection re-evaluations. Patients receiving steroid CEI experienced faster relief during the first postinjection week. The Straight Leg Rising test improved in both groups following CEI; this improvement was faster among steroid-group's patients. Fifty-one patients (27.8%), noticed no improvement 1 week post-CEI and underwent a second CEI (with the same preparation) 7 to 14 days later. Nineteen of them reported improvement; 32 (steroid-group:13, WFI-group:19) did not respond well and underwent operative decompression (n = 15) or spinal fusion (n = 17).

CONCLUSION

CEI containing local anesthetic and steroids or WFI seems to be effective when treating patients with LBP and sciatica. CEI containing steroid preparations demonstrated better and faster efficacy.

Determining the accuracy of caudal needle placement in children: a comparison of the swoosh test and ultrasonography

BACKGROUND

The aim of the present study was to compare two confirmatory tests - the 'swoosh' test (auscultation during caudal injection) and real time ultrasound imaging (both transverse 2D imaging and color flow Doppler imaging) in pediatric patients receiving a caudal epidural block.

METHODS/MATERIALS

This was a retrospective observational study of caudal injections administered to 83 pediatric patients (0-11 years) presenting for elective surgery over a 4 month time period. While injecting small aliquots of local anesthetic, a standard stethoscope was placed over the lower lumbar spine to auscultate for the 'swoosh' test. An ultrasound machine (Sonosite Titan, Sonosite Inc., Bothell, WA, USA) was then utilized for real-time visualization of caudal injectate. Each test performed during the caudal injection (swoosh, turbulence on 2D imaging, or color flow on Doppler imaging) was recorded as positive, negative or equivocal.

RESULTS

Eighty out of 83 patients (96.4%) had a successful caudal block based on minimal or no perioperative narcotic use, minimal or no response to surgical stimulation, the presence of motor blockade and patient comfort in the PACU. Ultrasound was significantly superior to 'swoosh' for sensitivity (96.3% vs 57.5%), negative predictive (40% vs 5.6 value) % and likelihood ratio (2.89 vs 1.73). Specificity and positive predictive value were not different between 'swoosh' and ultrasound. Of the ultrasound tests, turbulence was more sensitive than color flow Doppler (95.0% vs 78.8%).

CONCLUSION

Ultrasonography is superior to the 'swoosh' test as an objective confirmatory technique during caudal block placement in children. We found the presence or absence of turbulence during injection within the caudal space to be the best single indicator of caudal success. We think ultrasonography should be used, if available, when teaching this technique.

Caudal epidural injection versus non-steroidal anti-inflammatory drugs in the treatment of low back pain accompanied with radicular pain

OBJECTIVE

Low back pain is a highly common problem and causes much morbidity and socioeconomic loss in the community. Although the use of caudal epidural injections in the management of the low back pain with radicular signs is commonplace, it has not been well investigated. We compare the effectiveness of caudal epidural injection versus non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of low back pain accompanied with radicular pain.

METHODS

The study was a controlled prospective unblinded trial. A total of consecutive 64 patients with subacute or chronic low back pain accompanied with radicular pain were included. The patients were randomly allocated to two groups. First group was caudal epidural injection plus therapeutic exercise group, and the second group was NSAIDs plus therapeutic exercise group. Patients were assessed with 10 cm visual analogue scale for pain, straight leg raising test and Oswestry low back pain disability questionnaire at the beginning and at 15th day, 1st and 3rd month.

RESULTS

It was seen that both groups' improvement were good and statistically significant. On the other hand, caudal epidural injection group's improvement was better and faster than the NSAID group's, and the differences between assessment scores of the groups were statistically significant, except the 3rd month Oswestry scores.

CONCLUSION

Finally, caudal epidural injection in the management of the subacute/chronic low back and radicular pain is a preferable choice, if applied by experienced specialists.

Accuracy of caudal epidural injection: the importance of real-time imaging

Caudal epidural steroid injections are often used for low back pain. Fluoroscopic guidance has been frequently cited as a requirement for this procedure. In this preliminary report, we demonstrate that fluoroscopic guidance for caudal epidural Tuohy needle placement without real-time imaging may result in inadvertent intravenous injection of the drug. We detected intravenous leakage of the drug in 4 cases of 10 when real-time fluoroscopic imaging was used. Thus, real-time imaging may be recommended in addition to routine fluoroscopic guidance for caudal epidural procedures, as it may improve efficacy and safety by assuring accurate drug deposition.

Is a fall in baseline heart rate a reliable predictor of a successful single shot caudal epidural in children?

BACKGROUND

This study was designed to investigate whether a fall in heart rate (HR) with injection of local anesthetic into the caudal space can be used as a predictor of correct needle placement.

METHODS

Two hundred and twenty pediatric patients undergoing infraumbilical surgery were recruited to the study. After induction of general anesthesia, baseline HR was recorded and caudal block was performed using 0.75-1 ml x kg(-1) 0.25% bupivacaine, which was injected at a rate of 1 ml x 3 s(-1). The change in HR while injecting an initial 0.2 ml x kg(-1) of drug and during total drug injection was recorded. HR reduction of > or = 3 b x min(-1) was considered a positive test for correct needle placement. The success of block was judged by HR response to skin incision, endtidal halothane concentration required for maintenance of anesthesia and postoperative pain scores.

RESULTS

Caudal block was successful in 209/220 (95%) patients. Mean HR following the initial drug injection (111 +/- 17.7, P < 0.01) and entire drug injection (108.8 +/- 17.2, P < 0.01) was significantly lower than baseline (116.2 +/- 17.5). HR reduction of > or = 3 b x min(-1) was present in 190/209 and 199/209 successful block following initial drug injection and total drug injection respectively. The analysis of study data showed that a fall in HR is a predictor of successful caudal block, with a sensitivity of 90.9%, specificity of 100% and a positive predictive value of 100% after initial injection of local anesthetic.

CONCLUSIONS

We conclude that decrease in HR with drug injection is a simple, objective and reliable test to predict success of caudal block.

Comparison of 'whoosh' and modified 'swoosh' test for identification of the caudal epidural space in children

BACKGROUND

Caudal analgesia is widely used in pediatric anesthesia practice. The 'whoosh' test which uses air to identify the epidural space, has been recommended as a guide for successful needle placement. However, the use of air may be associated with an incidence of neurological complications. The 'swoosh' test avoids the injection of air and was originally performed using injection of a local anesthetic solution. A comparison was made between the 'whoosh' test and a modified 'swoosh' test using saline to identify the caudal epidural space in children.

METHODS

We studied 60 children of either sex in the age group of 2-8 years undergoing inguinal herniotomy. During insertion of the caudal block, a stethoscope was placed over the lower lumbar spine to note the presence or absence of 'whoosh' or 'swoosh', by an independent observer who was blinded to the injection of 1 ml of air or saline which was given simultaneously by the operator into the caudal space. The operator's clinical impression of successful insertion of the needle was also recorded and correlated with the presence or absence of 'whoosh' or 'swoosh'. In addition, the need for supplemental intraoperative analgesia was noted.

RESULTS

Overall success rate of caudal block using the 'whoosh' and modified 'swoosh' tests was found to be 96.6% and 93.3%, respectively as judged by the lack of supplementary perioperative analgesia. The sensitivity, specificity and positive predictive value of the 'whoosh' test and clinical predictors of caudal placement was found to be 100% whereas the modified 'swoosh' test had a sensitivity of 93%, specificity of 50% and a positive predictive value of 96%. However, statistically there was no significant difference between the clinical predictors, 'whoosh' and the modified 'swoosh' test for identification of the caudal epidural space.

CONCLUSIONS

The modified 'swoosh' test is as reliable as the 'whoosh' test and we recommend it for identification of the caudal epidural space in children as it avoids injection of air into the caudal space.

Preemptive analgesia for postoperative pain relief in lumbosacral spine surgeries: a randomized controlled trial

BACKGROUND CONTEXT

Administration of analgesic medication, before the actual onset of painful stimulus, is more effective than that after the onset of painful stimulus. This is the principle of preemptive analgesia. Although it is often considered superior to other forms of analgesia, its role in postoperative pain relief after lumbosacral spinal surgery has not been fully investigated.

PURPOSE

To analyze the efficacy of preemptive analgesia with a single caudal epidural injection for patients undergoing surgeries on the lumbosacral spine by the posterior approach.

STUDY DESIGN/SETTING

Randomized, double-blinded and controlled clinical trial.

PATIENT SAMPLE

Eighty-two patients who underwent discectomy in the lumbosacral spine by the posterior approach, with or without instrumentation, were randomized to the control group (n=40) and to the study group (n=42).

METHODS

Patients in control group received a single caudal epidural injection of 20 ml of normal saline. Patients in study group received a single caudal epidural injection of 20 ml containing bupivacaine and tramadol as the active agents. The time interval between this injection and the surgical incision was never less than 20 minutes in either of the groups. This facilitated enough time for the drug to get fixed to the nerve roots, leading to effective preemptive analgesia.

OUTCOME MEASURES

Patients were monitored for postoperative pain immediately after surgery when they had completely recovered and regained consciousness from general anesthesia, and subsequently 4, 8, 12 and 24 hours thereafter. Pain was quantified using the visual analog scale (VAS) and the verbal rating scale (VRS). The time at which supplemental analgesic medication was first demanded in the postoperative period by the patient was also noted.

RESULTS

The two groups were comparable for age, sex, body weight and the type of surgery they underwent. Because the data did not have a normal Gaussian distribution, the one-tailed Mann-Whitney test, being a nonparametric test, was adopted for statistical analysis. Accordingly, VAS and VRS values at all time intervals were significantly lower (p<.0001) in the study group as compared with the control group. This indicated significantly better pain relief in the study group. There was also a significant delay (p=.0041) in the first demand for supplemental analgesic medication in the postoperative period in the study group. No complication specific to the procedure was noted except for the development of postoperative urinary retention, which was transient and appropriately managed with urinary catheterization.

CONCLUSIONS

Preemptive analgesia with a single caudal epidural injection of bupivacaine and tramadol is a safe, simple and effective method for postoperative pain relief.

The dose of caudal epidural analgesia and duration of postoperative analgesia

BACKGROUND

Single dose caudal epidural is commonly utilized for postoperative analgesia in children. Previous studies have determined the optimal concentration of local anaesthetic, and the minimal volume to produce a desired dermatomal distribution. However, none has sought the optimal volume to administer. The specific aim of this study was to determine whether the volume of caudal epidural local anaesthetic influenced the duration of postoperative analgesia.

METHODS

Fifty-four children aged 1-6 years and ASAPS I-II scheduled for elective inguinal herniorraphy were enrolled in this randomized and blinded clinical trial. They received a standardized general anaesthetic with one of three possible doses of caudal epidural analgesic: 0.7, 1.0, or 1.3 ml.kg-1 of 0.175% bupivacaine with 1 : 200 000 epinephrine. The patients were assessed by blinded observers during in-hospital recovery and by parents at home.

RESULTS

The principal outcome measure of time until first postoperative analgesic requirement was similar between the groups (4.2, 3.6, and 4.8 h respectively). Other effects which might be altered by epidural analgesia, including time until first void, ambulation, and discharge readiness did not differ between groups.

CONCLUSIONS

Increasing local anaesthetic dose and volume do not increase the duration of postoperative analgesia of caudal epidural in children undergoing inguinal herniorraphy.

Comparison of the caudal and lumbar approaches to the epidural space

OBJECTIVES

To investigate the accuracy of placement of epidural injections using the lumbar and caudal approaches. To identify which factors, if any, predicted successful placement.

METHODS

200 consecutive patients referred to a pain clinic for an epidural injection of steroid were randomly allocated to one of two groups. Group L had a lumbar approach to the epidural space and group C a caudal approach to the epidural space. Both groups then had epidurography performed using Omnipaque and an image intensifier to determine the position of the needle.

RESULTS

Body mass index (BMI), grade of operator, and route of injection were predictors of a successful placement. 93% of lumbar and 64% of caudal epidural injections were correctly placed (p< 0.001). 97% of lumbar and 85% of caudal epidural injections clinically thought to be correctly placed were confirmed radiographically. For epidural injections where the clinical impression was "maybe", 91% of lumbar injections, but only 45% of caudal injections were correctly placed. Obesity was associated with a reduced chance of successful placement (odds ratio (OR) 0.34 (95% confidence interval (CI) 0.17 to 0.72) BMI >30 v BMI <30). A more senior grade of operator was associated with a reduced chance of successful placement (OR 0.16 (95% CI 0.03 to 0.89) consultant v other). However, small numbers may have accounted for the latter result.

CONCLUSIONS

The weight of the patient and intended approach need to be considered when deciding the method used to enter the epidural space. In the non-obese patient, lumbar epidural injections can be accurately placed without x ray screening, but caudal epidural injections, to be placed accurately, require x ray screening no matter what the weight of the patient.