Mark V. Boswell

Prevalence of facet joint pain in chronic spinal pain of cervical, thoracic, and lumbar regions

BackgroundFacet joints are a clinically important source of chronic cervical, thoracic, and lumbar spine pain. The purpose of this study was to systematically evaluate the prevalence of facet joint pain by spinal region in patients with chronic spine pain referred to an interventional pain management practice.MethodsFive hundred consecutive patients with chronic, non-specific spine pain were evaluated. The prevalence of facet joint pain was determined using controlled comparative local anesthetic blocks (1% lidocaine or 1% lidocaine followed by 0.25% bupivacaine), in accordance with the criteria established by the International Association for the Study of Pain (IASP). The study was performed in the United States in a non-university based ambulatory interventional pain management setting.ResultsThe prevalence of facet joint pain in patients with chronic cervical spine pain was 55% 5(95% CI, 49% – 61%), with thoracic spine pain was 42% (95% CI, 30% – 53%), and in with lumbar spine pain was 31% (95% CI, 27% – 36%). The false-positive rate with single blocks with lidocaine was 63% (95% CI, 54% – 72%) in the cervical spine, 55% (95% CI, 39% – 78%) in the thoracic spine, and 27% (95% CI, 22% – 32%) in the lumbar spine.ConclusionThis study demonstrated that in an interventional pain management setting, facet joints are clinically important spinal pain generators in a significant proportion of patients with chronic spinal pain. Because these patients typically have failed conservative management, including physical therapy, chiropractic treatment and analgesics, they may benefit from specific interventions designed to manage facet joint pain.

A Randomized, Controlled, Double-Blind Trial of Fluoroscopic Caudal Epidural Injections in the Treatment of Lumbar Disc Herniation and Radiculitis

Study Design. A randomized, controlled, double-blind trial. Objective. To assess the effectiveness of fluoroscopically directed caudal epidural injections in managing chronic low back and lower extremity pain in patients with disc herniation and radiculitis with local anesthetic with or without steroids. Summary of Background Data. The available literature on the effectiveness of epidural injections in managing chronic low back pain secondary to disc herniation is highly variable. Methods. One hundred twenty patients suffering with low back and lower extremity pain with disc herniation and radiculitis were randomized to one of the two groups: group I received caudal epidural injections with an injection of local anesthetic, lidocaine 0.5%, 10 mL; group II patients received caudal epidural injections with 0.5% lidocaine, 9 mL, mixed with 1 mL of steroid. The Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake were utilized with assessment at 3, 6, and 12 months posttreatment. Results. The percentage of patients with significant pain relief of 50% or greater and/or improvement in functional status with 50% or more reduction in ODI scores was seen in 70% and 67% in group I and 77% and 75% in group II with average procedures per year of 3.8 ± 1.4 in group I and 3.6 + 1.1 in group II. However, the relief with first and second procedures was significantly higher in the steroid group. The number of injections performed was also higher in local anesthetic group even though overall relief was without any significant difference among the groups. There was no difference among the patients receiving steroids. Conclusion. Caudal epidural injection with local anesthetic with or without steroids might be effective in patients with disc herniation or radiculitis. The present evidence illustrates potential superiority of steroids compared with local anesthetic at 1-year follow-up.

Secretion of brain-derived neurotrophic factor from brain microvascular endothelial cells

The cerebral microvasculature has recently been identified as a source of factors that can influence the generation and survival of neurons, including brain‐derived neurotrophic factor (BDNF). However, relatively little is known about signals that regulate secretion of endothelial cell derived BDNF. To approach this issue the present study examined BDNF secretion from brain endothelial cells in response to reduced oxygen availability (hypoxia), using the mouse brain microvascular endothelial cell line, bEnd.3. We found that exposure of bEnd.3 cells to either sustained or intermittent hypoxia (IH) stimulates BDNF expression and release and that IH is the more potent stimulus. IH‐induced BDNF release can be partially inhibited by either N‐acetyl‐l‐cysteine, a scavenger of reactive oxygen species, or by the stable superoxide dismutase mimetic manganese(III)tetrakis1‐methyl‐4‐pyridylporphyrin, indicating that oxyradical formation contributes to enhanced secretion of BDNF. In addition, we found that IH‐induced BDNF release requires Ca2+ mobilization from internal stores through ryanodine‐ and inositol (1,4,5‐triphosphate) IP3 receptors and is completely blocked by SKF 96365, a nonselective inhibitor of transient receptor potential (TRP) channels. These data demonstrate that bEnd.3 cells respond to oxidative stress by increasing BDNF secretion and, in addition, highlight TRP channels as potential therapeutic targets for enhancing BDNF availability from the cerebral microvasculature.

Secretion of brain-derived neurotrophic factor from PC12 cells in response to oxidative stress requires autocrine dopamine signaling

Expression of brain‐derived neurotrophic factor (BDNF) is sensitive to changes in oxygen availability, suggesting that BDNF may be involved in adaptive responses to oxidative stress. However, it is unknown whether or not oxidative stress actually increases availability of BDNF by stimulating BDNF secretion. To approach this issue we examined BDNF release from PC12 cells, a well‐established model of neurosecretion, in response to hypoxic stimuli. BDNF secretion from neuronally differentiated PC12 cells was strongly stimulated by exposure to intermittent hypoxia (IH). This response was inhibited by N‐acetyl‐l‐cysteine, a potent scavenger of reactive oxygen species (ROS) and mimicked by exogenous ROS. IH‐induced BDNF release requires activation of tetrodotoxin sensitive Na+ channels and Ca2+ influx through N‐ and L‐type channels, as well as mobilization of internal Ca2+ stores. These results demonstrate that oxidative stress can stimulate BDNF release and that underlying mechanisms are similar to those previously described for activity‐dependent BDNF secretion from neurons. Surprisingly, we also found that IH‐induced secretion of BDNF was blocked by dopamine D2 receptor antagonists or by inhibition of dopamine synthesis with α‐methyl‐p‐tyrosine. These data indicate that oxidative stress can stimulate BDNF release through an autocrine or paracrine loop that requires dopamine receptor activation.

Explosive growth of facet joint interventions in the medicare population in the United States: a comparative evaluation of 1997, 2002, and 2006 data

BackgroundThe Office of Inspector General of the Department of Health and Human Services (OIG-DHHS) issued a report which showed explosive growth and also raised questions of lack of medical necessity and/or indications for facet joint injection services in 2006.The purpose of the study was to determine trends of frequency and cost of facet joint interventions in managing spinal pain.MethodsThis analysis was performed to determine trends of frequency and cost of facet jointInterventions in managing spinal pain, utilizing the annual 5% national sample of the Centers forMedicare and Medicaid Services (CMS) for 1997, 2002, and 2006.Outcome measures included overall characteristics of Medicare beneficiaries receiving facet joint interventions, utilization of facet joint interventions by place of service, by specialty, reimbursement characteristics, and other variables.ResultsFrom 1997 to 2006, the number of patients receiving facet joint interventions per 100,000Medicare population increased 386%, facet joint visits increased 446%, and facet joint interventions increased 543%. The increases were higher in patients aged less than 65 years compared to those 65 or older with patients increasing 504% vs. 355%, visits increasing 587% vs. 404%, and services increasing 683% vs. 498%.Total expenditures for facet joint interventions in the Medicare population increased from over

INTERACTION OF GABA AND VOLATILE ANESTHETICS IN THE NEHATODE CAENORHABDITIS ELEGANS

229 million in 2002 to over

EFFICACY OF EPIDURAL INJECTIONS IN THE TREATMENT OF LUMBAR CENTRAL SPINAL STENOSIS: A SYSTEMATIC REVIEW

511 million in 2006, with an overall increase of 123%. In 2006, there was a 26.8-fold difference in utilization of facet joint intervention services in Florida compared to the state with the lowest utilization - Hawaii.There was an annual increase of 277.3% in the utilization of facet joint interventions by general physicians, whereas a 99.5% annual increase was seen for nurse practitioners (NPs) and certified registered nurse anesthetists (CRNAs) from 2002 to 2006. Further, in Florida, 47% of facet joint interventions were performed by general physicians.ConclusionsThe reported explosive growth of facet joint interventions in managing spinal pain in certain regions and by certain specialties may result in increased regulations and scrutiny with reduced access.

Dorsal Nerve Block for Management of Intraoperative Penile Erection

The authors tested whether mutant strains of Caenorhabditis elegans with altered sensitivity to volatile anesthetics have altered responses to GABA or GABA-agonists. They determined the ED50s of the wild-type strain N2 and two mutant strains of C. elegans to a GABA-mimetic ivermectin (IVM) and to GABA. unc-79, a strain with increased sensitivity to halothane, was more sensitive than N2 to IVM and GABA. unc-9, a strain that suppresses the increased sensitivity of unc-79 to halothane, was less sensitive than N2 to IVM and GABA. The authors also tested whether doses of GABA or IVM and volatile anesthetics were additive in their effects on C. elegans. Halothane (2.1%) did not shift the ED50 of IVM, but was antagonistic to GABA. Enflurane (4%) was antagonistic to both IVM and GABA. However, ED50s of halothane and enflurane were unchanged in the presence of IVM (35 nM) or GABA (150 mM). The authors conclude that GABA by itself does not appear to mediate halothane or enflurane sensitivity in C. elegans.

Superior hypogastric plexus block successfully treats severe penile pain after transurethral resection of the prostate

Context: Lumbar central spinal stenosis is common and often results in chronic persistent pain and disability, which can lead to multiple interventions. After the failure of conservative treatment, either surgical or nonsurgical modalities such as epidural injections are contemplated in the management of lumbar spinal stenosis. Evidence Acquisition: Recent randomized trials, systematic reviews and guidelines have reached varying conclusions about the efficacy of epidural injections in the management of central lumbar spinal stenosis. The aim of this systematic review was to determine the efficacy of all three anatomical epidural injection approaches (caudal, interlaminar, and transforaminal) in the treatment of lumbar central spinal stenosis. A systematic review was performed on randomized trials published from 1966 to July 2014 of all types of epidural injections used in the management of lumbar central spinal stenosis. Methodological quality assessment and grading of the evidence was performed. Results: The evidence in managing lumbar spinal stenosis is Level II for long-term improvement for caudal and lumbar interlaminar epidural injections. For transforaminal epidural injections, the evidence is Level III for short-term improvement only. The interlaminar approach appears to be superior to the caudal approach and the caudal approach appears to be superior to the transforaminal one. Conclusions: The available evidence suggests that epidural injections with local anesthetic alone or with local anesthetic with steroids offer short- and long-term relief of low back and lower extremity pain for patients with lumbar central spinal stenosis. However, the evidence is Level II for the long-term efficacy of caudal and interlaminar epidural injections, whereas it is Level III for short-term improvement only with transforaminal epidural injections.

Hydrocodone in postoperative personalized pain management: pro-drug or drug?

Intraoperative penile erection during general anesthesia can delay or prevent the completion of cystoscopic or penile surgical procedures. The dorsal penile nerve block is offered as a treatment for intraoperative erection. Advantages of this technique include less potential for cardiovascular complications and improved postoperative analgesia.