Lumbar epidural blocks: a case report of a life-threatening complication

Evaluation of prostaglandin D2 as a CSF leak marker: implications in safe epidural anesthesia

Background

It is accepted that there is a severe risk of dural puncture in epidural anesthesia. Of major concern to anesthesiologists is unintentional spinal block. Reliable identification of cerebrospinal fluid (CSF) from the aspirate is crucial for safe epidural anesthesia. The aim of this study was to determine whether prostaglandin D2 could be clinically used as a marker for the detection of CSF traces.

Methods

After obtaining Institutional Review Board approval and patient consent, CSF was obtained from patients undergoing spinal anesthesia, and blood, urine, and saliva were obtained from normal subjects and analyzed for prostaglandin D2 (PGD). CSF (n=5) samples were diluted with local anesthetic (bupivacaine), normal saline and blood in the ratios of 1:5 and 1:10. PGD levels in the CSF samples were analyzed with a PGD-Methoxime (MOX) EIA Kit (Cayman Chemicals, MI). This assay is based on the conversion of PGD to a stable derivative, which is analyzed with antiserum specific for PGD-MOX.

Results

Different concentrations of pure PGD-MOX conjugate were analyzed by EIA and a standard curve was derived. PGD levels in CSF and CSF with diluents were determined and the values were extrapolated onto the standard curve. Our results show a well-defined correlation for the presence of PGD both in straight CSF samples and in diluted CSF (dilution factor of 1:5 and 1:10).

Conclusion

Prostaglandin D2 was reliably identified in CSF by enzyme-linked immunosorbent assay when diluted with local anesthetic, saline, and serum, and can be used as a marker to identify the presence of CSF in epidural aspirates.

Clinical presentation of local anesthetic systemic toxicity: a review of published cases, 1979 to 2009

The classic description of local anesthetic systemic toxicity (LAST) generally described in textbooks includes a series of progressively worsening neurologic symptoms and signs occurring shortly after the injection of local anesthetic and paralleling progressive increases in blood local anesthetic concentration, culminating in seizures and coma. In extreme cases, signs of hemodynamic instability follow and can lead to cardiovascular collapse. To characterize the clinical spectrum of LAST and compare it to the classic picture described above, we reviewed published reports of LAST during a 30-year period from 1979 to 2009. Ninety-three cases were identified and analyzed with respect to onset of toxicity and the spectrum of signs and symptoms. Sixty percent of cases followed the classic pattern of presentation. However, in the remainder of cases, symptoms were substantially delayed after the injection of local anesthetic, or involved only signs of cardiovascular compromise, with no evidence of central nervous system toxicity. Although information gained from retrospective case review cannot establish incidence, outcomes, or comparative efficacies of treatment, it can improve awareness of the clinical spectrum of LAST and, theoretically, the diagnosis and treatment of affected patients. The analytic limitations of our method make a strong case for developing a prospective, global registry of LAST as a robust alternative for educating practitioners and optimizing management of LAST.

The efficacy of plethysmographic pulse wave amplitude as an indicator for intravascular injection of epinephrine-containing epidural test dose in anesthetized adults

In this study, I evaluated the efficacy of plethysmographic pulse wave amplitude (PPWA) in detecting intravascular injection of a simulated epidural test dose containing 15 microg of epinephrine in adults during either sevoflurane or isoflurane inhaled anesthesia and compared its reliability to the classical heart rate (HR; positive if > or =10 bpm) and systolic blood pressure (SBP; positive if > or =15 mm Hg) criteria. Eighty patients were randomized to receive either 1 mean alveolar anesthetic concentration of sevoflurane or 1 mean alveolar anesthetic concentration of isoflurane (n = 40 for each anesthesia group). Patients in each anesthesia group microg of epinephrine IV or 3 mL of saline IV (n = 20 each). HR, SBP, and PPWA were monitored for 5 min after injection. Injection of the test dose resulted in peak PPWA decrease by 61% +/- 17% and 58% +/- 15% at 61 +/- 12 s and 63 +/- 13 s in the sevoflurane and isoflurane groups, respectively. Positive PPWA criterion, as determined from peak increases during saline administration, was a decrease in PPWA > or =10%. Using this value, the sensitivity, specificity, positive predictive, and negative predictive values of PPWA were 100% in both anesthetic groups. On the contrary, sensitivities of 85% and 95% were obtained based on HR criterion in the sevoflurane and isoflurane patients, respectively, and a sensitivity of 90% was obtained in both anesthesia groups on the basis of SBP criterion. In conclusion, PPWA is a reliable alternative to conventional hemodynamic criteria for detection of an intravascular injection of epidural test dose.

Complications and side effects of cervical and lumbosacral selective nerve root injections

OBJECTIVE

To determine the incidence of complications and side effects of cervical and lumbosacral selective nerve root injections (SNRIs).

DESIGN

Prospective, nonrandomized controlled trial of consecutive patients with independent interviews for immediate, 1-week, and 3-month follow-ups.

SETTING

Tertiary, academic spine center.

PARTICIPANTS

Of 160 patients eligible for SNRI, 151 underwent 306 SNRIs (study group). Sixty patients who had not undergone any intervention served as the control group.

INTERVENTIONS

Diagnostic and therapeutic fluoroscopically guided cervical and lumbosacral SNRIs. Lidocaine (Xylocaine) was used in the diagnostic injections and a mixture of lidocaine and betamethasone was used in the therapeutic injections.

MAIN OUTCOME MEASURES

Complications and side effects experienced during the procedure were recorded by the interventionalist. Side effects and complications experienced immediately, 1 week, and 3 months after injection were determined through independent interviews using a questionnaire format. The control group was independently interviewed using the same questionnaire.

RESULTS

There were no major complications, such as death, paralysis, spinal nerve injury, infection, or allergic reaction, during the study. Ninety-one percent of subjects had no side effects during the procedure. A positive response on interview was reported by 39.4% of the study subjects immediately after the procedure. Lumbosacral SNRI side effects were as follows: increased pain at the injection site (17.1%); increased radicular pain (8.8%); lightheadedness (6.5%); increased spine pain (5.1%); nausea (3.7%); nonspecific headache (1.4%); and vomiting (0.5%). Immediate side effects from cervical SNRI were as follows: increased pain at injection site (22.7%); increased radicular pain (18.2%); lightheadedness (13.6%); increased spine pain (9.1%); nonspecific headache (4.5%); and nausea (3.4%). At the 1-week interview, comparison of the study and control groups showed statistical significance for the following: pain at injection site, cervical ( P =.001) and lumbar ( P =.005); nonspecific headache, cervical ( P =.019); and nonspinal headache, cervical ( P =.002). At 3 months, 2 subjects complained of increased neck pain and 1 reported heartburn and fluid retention. Two lumbar SNRI subjects were lost to follow-up.

CONCLUSIONS

There were no major complications with cervical and lumbosacral SNRIs, although various minor side effects occurred.

Diagnostic selective nerve root blocks: indications and usefulness

Diagnostic SNRIs are a useful tool in the diagnosis of radicular pain in atypical presentations. Diagnostic SNRI is indicated in the following circumstances: (1) for atypical extremity pain; (2) when imaging studies and clinical presentation do not correlate; (3) when electromyography and MRI are not corroborative or are equivocal; (4) for anomalous innervations, such [figure: see text] as conjoint nerve roots or furcal nerves [71]; (5) for failed back surgery syndrome with atypical extremity pain; and (6) for transitional vertebrae. Patients should have demonstrated a failure to improve with less invasive treatment. In these patients, a diagnostic SNRI may localize the pain to a specific spinal nerve. It must be emphasized that the diagnostic SNRI only determines if pain is emanating from a specific nerve root or spinal nerve. A diagnostic SNRI does not determine what has caused the nerve root or spinal nerve pain, nor does it provide prognostic information. The etiology of the nerve root pain, mechanism of injury, underlying anatomy, duration of symptoms, comorbidities, patient desire, physician skill, and a host of other factors determine the appropriate treatment and prognosis.