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Utility of an Epidural Pressure Checker in the Administration of Trans-Laminar Epidural Blocks
... This process does not involve the injection of any material; it only detects pressure gradient in the air that occurs naturally. The optimal pressure was determined in our previous study [23]. While advancing the needle, the cap is locked to secure the epidural space and the device is closed. ...
... Zarzur et al. studied 30 patients who underwent epidural anesthesia and found that the pressure within their epidural space was 0 to −0.16 psi [52]. Lee et al. reported that the optimal pressure value that helps detect the epidural space was −5 mbar [23]. The EPI-Detection TM detects the negative pressure in the epidural space and instantly notifies a physician by flashing a light and producing beeping sound. ...
Cervical epidural injection (CEI), which is widely used for the treatment of cervical radiculopathy, sometimes has been associated with post-operative complications. Recently, EPI-DetectionTM, which detects the negative pressure of the epidural space and notifies the proceduralist by flashing a light and producing a beeping sound, was introduced. We assumed that the newly developed device could be as safe and efficient as the conventional loss of resistance (LOR) method. Therefore, we aimed to evaluate the effectiveness of the EPI-DetectionTM and compare it to that of the conventional LOR method. We randomly assigned 57 patients to the LOR and EPI-Detection groups (29 and 28 patients, respectively). Subjects were treated with interlaminar CEI (ILCEI) using one of two methods. The measured parameters, i.e., operation time and radiation dose were lower in the EPI-DetectionTM group (4.6 ± 1.2 min vs. 6.9 ± 2.1 min; and 223.2 ± 206.7 mGy·cm2 vs. 380.3 ± 340.9 mGy·cm2, respectively; all p < 0.05) than in the LOR group. There were no complications noted in either group. Both the EPI-DetectionTM and LOR methods were safe and effective in detecting the epidural space, but the former was superior to the latter in terms of operation time and radiation exposure. The EPI-DetectionTM may help perform ILCEI safely.
Epidural block is a complex procedure and requires cognitive skills such as the knowledge of the anatomy and of the procedure along with psychomotor skills such as the skills required to perform the technique.
These are the words used by Dogliotti [1] to describe his own loss-of-resistance technique to identify the epidural space: “When the needle has penetrated the ligamentum interspinous for a certain distance and before it has gone through the ligamenta subflava into the spinal canal one removes the trocar and attaches a syringe filled with physiological saline. When an attempt is made to inject this fluid a very great resistance is met with since the interspinous Ligamentum and the Ligamenta subflava are so dense. If they can be injected at all, it will be only after the employment of considerable force. This resistance is most certain evidence that the needle is still in the posterior fibers of these tissues. The following maneuvers are then carried out: the syringe is held in one hand the thumb of which applies a continued and uniform pressure to the piston. The other hand slowly advances the needle into the tissues and when it has traversed a few millimeters the hand which is holding it will suddenly note a diminution in the resistance to its passage which has previously been due to the tissues of the ligamenta subflava. At the same instant the injection fluid enters freely. This is certain, practical and unequivocal evidence that the point of the needle has pierced the Ligamenta subflava and is in the peridural space which offers no resistance to the flow of the injected fluid. As soon as this position has been recognized the needle should be left in the position which it now occupies for its point is in the peridural space; any attempt to advance it farther would entail the risk of penetrating the dura.”
Over the course of the last decade, newer techniques and emerging technologies for locating and confirming entry into the epidural space have been explored to decrease failures and complications.
The traditional contraindications to epidural block are skin infections at the site of puncture, coagulopathy, and sepsis, although these are not the only risk factors for spinal hematoma and abscess, and uncorrected maternal hypovolemia (hemorrhage). Particular precautions should be taken with patients with intracranial lesions and spinal malformations. Inadequate training and experience and patient refusal or inability to cooperate may be added to the list, but such a constraint applies to any treatment that is offered.
“A number of variables determine how far neural blockade will spread after injection of an analgesic solution into the epidural space. Some of these are intrinsic to the patient, and some are extrinsic, depending on variations of technique and the drugs employed”: with these words Philip Bromage opened his cornerstone paper “Spread of analgesic solutions in the epidural space and their site of action” in 1962 [1]. In this classical work he postulated that the spread from an epidural injection could have two components: (1) spread within the epidural space itself, depending on the volume, speed of injection, posture, age, height, etc., and (2) subdural and subpial spread, which could have been proportional to the diffusion coefficient, the area of contact, the concentration gradient, and the time of contact. He observed that ultimately the segmental spread was dependent on the mass of analgesic solute available for transneuronal diffusion in the epidural space. He also observed that the “appropriate mass of solute can be presented in the form of a large volume of weak solution, in which case it will travel widely in the epidural space and diffuse relatively poorly or as a very small volume of concentrated material … where presumably epidural spread was limited by the small volumes used, but where the neuraxial spread was extensive owing to the high concentration gradient.” The final conclusions of Prof Bromage are still valid today: “The outcome of an epidural injection is the resultant of many different forces. If any of these is unusually weak, or another particularly strong, we may expect that clinical results will deviate from normal, and the accuracy of our results will depend on our ability to choose the appropriate dose with intelligent anticipation.”
“Last November, whilst giving a spinal anaesthetic, it occurred to me to block the nerves between the intervertebral spaces and the meninges rather than pierce the dura.” This is the first description on the intentional injection of anesthetic drugs in the lumbar epidural space, as described by the Spanish surgeon Fidel Pages in 1921 [1].
Background. The hanging drop (HD) technique presumably relies on the presence of subatmospheric epidural pressure. It is not clear whether this negative pressure is intrinsic or an artifact and how it is affected by body position. There are few data to indicate how often HD is currently being used. Methods. We identified studies that measured subatmospheric pressures and looked at the effect of the sitting position. We also looked at the technique used for cervical and thoracic epidural anesthesia in the last 10 years. Results. Intrinsic subatmospheric pressures were measured in the thoracic and cervical spine. Three trials studied the effect of body position, indicating a higher incidence of subatmospheric pressures when sitting. The results show lower epidural pressure (-10.7 mmHg) with the sitting position. 28.8% of trials of cervical and thoracic epidural anesthesia that documented the technique used, utilized the HD technique. When adjusting for possible bias, the rate of HD use can be as low as 11.7%. Conclusions. Intrinsic negative pressure might be present in the cervical and thoracic epidural space. This effect is more pronounced when sitting. This position might be preferable when using HD. Future studies are needed to compare it with the loss of resistance technique.
Epidrum(®) is an optimal pressure, loss of resistance device for identifying the epidural space. We investigated the usefulness of Epidrum versus the loss of resistance or hanging drop techniques while performing epidural anesthesia. Eighty adult patients who were scheduled for elective surgery under lumbar epidural anesthesia were randomized into two groups. The first group (Epidrum group) consisted of 40 adult patients who were scheduled for epidural anesthesia using Epidrum. The second group (control group) consisted of 40 adult patients who were scheduled for epidural anesthesia using the loss of resistance or hanging drop technique. We recorded the time required to identify the epidural space and outcomes of epidural catheterization. The attending anesthesiologists were also questioned regarding the ease of control of the Tuohy needle and of epidural space identification with each method. The time required to perform epidural anesthesia was significantly shorter in the Epidrum group than in the control group [28 s (10-76) vs. 90 s (34-185); median (interquartile range)] (p < 0.05). Tuohy needle control was significantly easier in the Epidrum group than in the control group (p < 0.05). Epidrum is useful for performing epidural anesthesia quickly while obtaining good Tuohy needle control.
The relation of intracranial pressure to headache has long been a subject of interest, but the available experimental data are limited. The experimental approach to the immediate effect of drainage of cerebrospinal fluid as a headache mechanism has been made by only a few investigators.¹ In contrast, the headache which so often follows routine lumbar puncture has been studied by many. Such headache has been ascribed by a minority to increased,² and by most to decreased, intracranial pressure.³
The mechanism of the other common headache often linked with altered intracranial pressure, that occurring with tumor of the brain, has had less attention. As Northfield⁴ emphasized, a necessary relation between the headache and the increased intracranial pressure has been proved.
With these issues in the foreground, the purposes of this investigation were as follows:
• To ascertain the mechanism of headache following experimental drainage of cerebrospinal fluid.
• To
Summary An epidemiological survey of cervical radiculopathy in Rochester, Minnesota, 1976–90, through the records-linkage system of the Mayo Clinic ascertained 561 patients (332 males and 229 females). Ages ranged from 13 to 91 years; the mean age ±SD was 47.6±13.1 years for males and 48.2±13.8 years for females. A history of physical exertion or trauma preceding the onset of symptoms occurred in only 14.8% of cases. A past history of lumbar radiculopathy was present in 41%. The median duration of symptoms prior to diagnosis was 15 days. A monoradiculopathy involving C7 nerve root was the most frequent, followed by C6. A confirmed disc protrusion was responsible for cervical radiculopathy in 21.9% of patients; 68.4% were related to spondylosis, disc or both. During the median duration of follow-up of 4.9 years, recurrence of the condition occurred in 31.7%, and 26% underwent surgery for cervical radiculopathy. A combination of radicular pain and sensory deficit, and objective muscle weakness were predictors of a decision to operate. At last follow-up 90% of our population-based patients were asymptomatic or only mildly incapacitated due to cervical radiculopathy. The average annual age-adjusted incidence rates per 100 000 population for cervical radiculopathy in Rochester were 83.2 for the total, 107.3 for males and 63.5 for females. The age-specific annual incidence rate per 100 000 population reached a peak of 202.9 for the age group 50–54 years.
A hypothesis is suggested that the initial or ‘true’ negative pressure encountered when a needle first enters the epidural space is due to initial bulging of the ligamentum flavum in front of the advancing needle followed by its rapid return to the resting position once the needle has perforated the ligament. The bulging has been confirmed to occur in fresh cadavers, and pressure studies carried out during performance of epidural blocks in patients lend weight to this hypothesis.
Low back pain without disc herniation is the most common problem among chronic pain disorders. Epidural injections are commonly used interventions in managing chronic low back pain without disc herniation. However, little evidence exists regarding the effectiveness, indications, and medical necessity of lumbar epidural injections in managing axial low back pain without disc herniation or radiculitis.
A randomized, double-blind, controlled trial.
An interventional pain management practice, a specialty referral center, a private practice setting in the United States.
To evaluate the ability to provide effective and long-lasting pain relief with lumbar interlaminar epidural injections with local anesthetic with or without steroids in managing chronic low back pain not caused by disc herniation or radiculitis.
Patients were randomly assigned to one of 2 groups with Group I patients receiving local anesthetic only, whereas Group II patients received local anesthetic mixed with non-particulate betamethasone. Seventy patients were included in this analysis. Randomization was performed by computer-generated random allocation sequence by simple randomization.
Outcome measures included the Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake. The assessments were done at baseline, 3 months, 6 months, and 12 months post-treatment. Significant pain relief and/or improvement in disability were defined as at least 50% improvement.
Significant pain relief (> or = 50%) was demonstrated in 74% of patients in Group I and 63% in Group II. Functional status improvement (reduction of > or = 50%) in the ODI scores was seen in 71% of patients in Group I and 60% of patients in Group II. The overall average procedures per year were approximately 4.
The results of this study are limited by the lack of a placebo group and a preliminary report of 35 patients in each group with a total of 70 patients.
Lumbar interlaminar epidural injections of local anesthetic with or without steroids was effective in 63% and 74% of patients with chronic function-limiting low back pain without facet joint pain, disc herniation, and/or radiculitis.
Accurate United States data on the prevalence of low-back pain (LBP) and its related medical care would assist health care planners, policy makers, and investigators. Data from the second National Health and Nutrition Examination Survey (NHANES II) were analyzed to provide such information. The cumulative lifetime prevalence of LBP lasting at least 2 weeks was 13.8%. In univariate analyses, important variations in prevalence were found by age, race, region, and educational status. Most persons with LBP sought care from general practitioners, with orthopaedists and chiropractors being the next most common sources of care. Sources of care, and in some cases therapy, varied among demographic subgroups. These data demonstrate substantial nonbiologic influences on the prevalence and treatment of LBP, and suggest an agenda for health services researchers.
To determine the therapeutic value and long-term effects of fluoroscopic transforaminal epidural steroid injections in patients with refractory radicular leg pain.
Although numerous studies have evaluated the efficacy of traditional transsacral (caudal) or translaminar (lumbar) administration of epidural steroids, to our knowledge no studies have assessed specifically the therapeutic value of fluoroscopic transforaminal epidural steroids.
A prospective case series that investigated the outcome of patients with lumbar herniated nucleus pulposus and radiculopathy who received fluoroscopic transforaminal epidural steroid injections.
Patients who met our inclusion criteria received fluoroscopically guided, contrast-enhanced transforaminal epidural administration of anesthetic and steroid directly at the level and side of their documented pathology. Patients were evaluated by an independent observer and received sequential questionnaires before and after injection, documenting pain level, activity level, and patient satisfaction.
Sixty-nine patients met our inclusion criteria and were followed for an average period of 80 weeks (range, 28 to 144 weeks); 75.4% of patients had a successful long-term outcome, reporting at least a >50% reduction between preinjection and postinjection pain scores, as well as an ability to return to or near their previous levels of functioning after only 1.8 injections per patient (range, 1 to 4 injections). Of our patients, 78.3% were satisfied with their final outcomes.
Fluoroscopic transforminal epidural steroids are an effective nonsurgical treatment option for patients with lumbar herniated nucleus pulposus and radiculopathy in whom more conservative treatments are not effective and should be considered before surgical intervention.
Although the literature is filled with information about the prevalence and incidence of back pain in general, there is less information about chronic back pain, partly because of a lack of agreement about definition. Chronic back pain is sometimes defined as back pain that lasts for longer than 7-12 weeks. Others define it as pain that lasts beyond the expected period of healing, and acknowledge that chronic pain may not have well-defined underlying pathological causes. Others classify frequently recurring back pain as chronic pain since it intermittently affects an individual over a long period. Most national insurance and industrial sources of data include only those individuals in whom symptoms result in loss of days at work or other disability. Thus, even less is known about the epidemiology of chronic low-back pain with no associated work disability or compensation. Chronic low-back pain has also become a diagnosis of convenience for many people who are actually disabled for socioeconomic, work-related, or psychological reasons. In fact, some people argue that chronic disability in back pain is primarily related to a psychosocial dysfunction. Because the validity and reliability of some of the existing data are uncertain, caution is needed in an assessment of the information on this type of pain.
Spinal epidural hematoma after spinal puncture such as for injection of steroids for pain management may result in a rare complication of a spinal epidural hematoma causing acute myelopathy. Although this complication is well known with epidural anesthesia, where it is usually seen with impaired hemostasis, there are surprisingly few case reports of epidural hematoma after an epidural steroid block.
A healthy 34-year-old man with no evidence of coagulopathy and not taking antiplatelet medication suddenly had onset of acute cervical myelopathy from a large cervical epidural hematoma 8 days after a cervical epidural steroid block. Following prompt surgical evacuation of the clot, the patient made a near complete recovery.
Spinal epidural hematoma after spinal puncture is usually associated with impaired hemostasis. This case illustrates that it may occur in the absence of known risk factors. The delayed onset and the absence of risk factors have implications for the use of this procedure in chronic pain management.
Unlabelled:
Sixty patients scheduled for lumbar epidural anesthesia were included in a study in which we evaluated the efficacy of localizing the epidural space by means of an acoustic signal. A prototype of an acoustic puncture assist device, connected to the epidural needle by an extension tube, generated the pressure needed to perform the epidural puncture and translated this pressure into corresponding acoustic and visible signals. The device frees the anesthesiologist to handle the epidural needle with both hands and to detect the epidural space by means of these signals. In all 60 patients (100%), the epidural space was successfully located by using the acoustic signal. In all cases, this was confirmed by the pressure measurement, which proved to be a reliable indicator for correct identification of the epidural space. We conclude that it is possible to locate the epidural space by means of the acoustic puncture assist device. The method proved to be reliable, safe, and simple in this study. The benefits of this new epidural puncture technique include better needle control, teaching, control of correct catheter placement, and documentation. The last can be an important adjunct to anesthesia practice.
Implications:
The authors demonstrate that it is possible to identify the epidural space by an acoustic and visible signal. An experimental setup constructed for this purpose makes the epidural puncture procedure audible and visible.
The effects of epidural needle design, angle, and bevel orientation on cerebrospinal fluid leak after puncture have not been reported. The impact of these factors on leak rate was examined using a dural sac model. Dural trauma was examined using scanning electron microscopy.
Human cadaveric dura, mounted on a cylindrical model, was punctured with epidural needles using a micromanipulator. Tissue was punctured at 15 cm H2O (left lateral decubitus) system pressure, and leak was measured at 25 cm H2O (semisitting) pressure. Leak rates and trauma were compared for the following: (1) six different epidural needles at 90 degrees, bevel parallel to the dural long axis; (2) 18-gauge Tuohy and 18-gauge Special Sprotte epidural needles, 30 degrees versus 90 degrees; (3) 18-gauge Tuohy, bevel perpendicular versus parallel to the dural long axis.
With the 90 degrees puncture, bevel parallel, the greatest leak occurred with a 17-gauge Hustead (516 +/- 319 ml/15 min), and the smallest leak occurred with a 20-gauge Tuohy (100 +/- 112 ml/15 min; P = 0.0018). A 20-gauge Tuohy puncture led to statistically significant reductions in leak (P value range, 0.0001-0.0024) compared with all needles except the Special Sprotte. With the 30 degrees versus 90 degrees angle, 30 degrees punctures with an 18-gauge Tuohy produced nonstatistically significant leak reductions compared with the 18-gauge Tuohy at 90 degrees. The puncture angle made no difference for the Special Sprotte. Nonsignificant reductions were found for the Special Sprotte compared with the Tuohy. With the 18-gauge Tuohy bevel orientation, perpendicular orientation produced nonstatistically significant reductions in leak compared with parallel orientation.
Cerebrospinal fluid leak after puncture was influenced most by epidural needle gauge. Leak rate was significantly less for the 20-gauge Tuohy needle.
The hanging drop technique identifies the epidural space using the negative pressure of this space. Although the hanging drop technique is popular at the thoracic level, there is still controversy on the negative epidural pressure at this level. The authors hypothesized that the epidural pressure is more consistently negative in the sitting position than in the lateral decubitus position at the thoracic level.
This study compared the epidural pressures of 28 awake patients in the sitting (sitting group, n = 14) or lateral decubitus (lateral group, n = 14) position. The T5-T6 epidural pressure was measured using a closed pressure measurement system connected to a Tuohy needle.
All of the thoracic epidural pressures in the sitting group were negative (median, -5 mmHg; range, -18 to -1; mean, -7.2; SD, 6.3), in contrast to the lateral group (median, 5 mmHg; range, -4 to 13; mean, 5.1; SD, 4.4). The thoracic epidural pressure in the sitting group was significantly lower than in the lateral group (P < 0.001).
The thoracic epidural pressure is more negative in the sitting position than in the lateral decubitus position. These results suggest that the patient should be sitting when the hanging drop technique is used to identify the epidural space.
Pear BL : Spinal epidural hematoma
Pear BL : Spinal epidural hematoma. Am J Roentgenol Radium Ther
Nucl Med 115 : 155-164, 1972