Radiofrequency sacroiliac joint denervation for sacroiliac syndrome.

BACKGROUND AND OBJECTIVES: Radiofrequency (RF) denervation of the sacroiliac (SI) joint has been advocated for the treatment of sacroiliac syndrome, yet no clinical studies or case series support its use. METHODS: We report the results of a consecutive series of 50 SI joint RF denervations performed in 33 patients with sacroiliac syndrome. All patients underwent diagnostic SI joint injections with local anesthetic before denervation. Changes in visual analog pain scores (VAS), pain diagrams, physical examination (palpation tenderness over the joint, myofascial trigger points overlying the joint, SI joint pain provocation tests, and range of motion of the lumbar spine), and opioid use were assessed pre- and postdenervation. RESULTS: The criteria for successful RF denervation were at least a 50% decrease in VAS for a period of at least 6 months; 36.4% of patients (12 of 33) met these criteria. Failure of denervation correlated with the presence of disability determination and pain on lateral flexion to the affected side. The average duration of pain relief was 12.0 +/- 1.2 months in responders versus 0.9 +/- 0.2 months in nonresponders (P < or = 0.0001). A positive response was associated with an atraumatic inciting event. Successful denervation was associated with a change in the pain diagram and a reduction in the pattern of referred pain, a normalization of SI joint pain provocation tests, and a reduction in the use of opioids. CONCLUSIONS: This study suggests that RF denervation of the SI joint can significantly reduce pain in selected patients with sacroiliac syndrome for a protracted time period. Moreover, certain abnormal physical findings (i.e., SI joint pain provocation tests) revert to normal for the duration of the analgesia.

Evidence-based review of the literature on intrathecal delivery of pain medication.

Evidence-based medicine depends on the existence of controlled clinical trials that establish the safety and efficacy of specific therapeutic techniques. Many interventions in clinical practice have achieved widespread acceptance despite little evidence to support them in the scientific literature; the critical appraisal of these interventions based on accumulating experience is a goal of medicine. To clarify the current state of knowledge concerning the use of various drugs for intraspinal infusion in pain management, an expert panel conducted a thorough review of the published literature. The exhaustive review included 5 different groups of compounds, with morphine and bupivacaine yielding the most citations in the literature. The need for additional large published controlled studies was highlighted by this review, especially for promising agents that have been shown to be safe and efficacious in recent clinical studies.

Clinical guidelines for intraspinal infusion: report of an expert panel. PolyAnalgesic Consensus Conference 2000.

Consensus guidelines developed by an expert panel are helpful to clinicians when there is variation in practice and lack of a firm evidence base for an intervention, such as intraspinal therapy for pain. An internet-based survey of practitioners revealed remarkable variation in practice patterns surrounding intraspinal therapy. This prompted an interdisciplinary panel with extensive clinical experience in intraspinal infusion therapy to evaluate the results of the survey, the systematic reviews of the literature pertaining to this approach, and their own clinical experience with long-term spinal infusions. The panel proposed a scheme for the selection of drugs and doses for intraspinal therapy, and suggested guidelines for administration that would increase the likelihood of a successful outcome. These expert panel guidelines were designed to provide an initial structure for clinical decision making that is based on the best available evidence and the perspectives of experienced clinicians.

Irreversible spinal cord injury as a complication of subarachnoid ethanol neurolysis.

Subarachnoid neurolysis using ethanol to destroy selectively the posterior roots of the spinal cord is a method for providing pain relief in patients with advanced cancer. Weakness of the extremities is a complication of the procedure that has been attributed to spread of the neurolytic agent to the anterior roots. The authors provide evidence of spinal cord injury as a cause of lower extremity weakness in a patient after subarachnoid ethanol neurolysis.

Neuraxial infusion in the management of cancer pain.

Pain due to malignancy can be controlled through simple means in most patients. In certain refractory cases, however, the chronic delivery of analgesics to the epidural or subarachnoid space may be appropriate. This review will discuss criteria for patient selection for neuraxial drug delivery, the technologic systems available for neuraxial drug delivery, and criteria for selection of the appropriate technology in the individual patient.

High-performance liquid chromatographic analysis of the 2-chloroprocaine metabolite, diethylaminoethanol, in blood and serum.

BACKGROUND AND OBJECTIVES: 2-Chloroprocaine is rapidly metabolized in the blood to yield 2-chloro-para-aminobenzoic acid (an inactive metabolite) and diethylaminoethanol (DEAE). DEAE possesses local anesthetic activity. The only reported assay for DEAE is a colorimetric method. METHODS: Clinical samples of whole blood and serum were obtained from patients receiving stepped intravenous infusions of 3% 2-chloroprocaine. A high pH-dependent liquid-liquid extraction step with diethyl ether was used to eliminate interfering peaks in high-pressure liquid chromatography (HPLC) analysis. Separation and quantitation were performed using HPLC on a polymeric-reversed phase column with a mobile phase consisting of 10% or 20% acetonitrile (for whole blood or serum analysis, respectively) in 50 mm aqueous sodium phosphate buffer, pH = 11.50. The elution order of DEAE and its analogues was tested to interpret the HPLC separation mechanism. RESULTS: Extraction recovery of DEAE from whole blood was 67 +/- 13.5%, from serum, 71 +/- 12.2%, and from water, 75 +/- 2.9%. The high pH value of the mobile phase resulted in sharp, well-resolved peaks with run times of approximately 8 minutes using 20% acetonitrile. The lower limit of detection was 5 ng/mL of DEAE from a 1-mL sample. The elution order of DEAE and its analogues indicated that separation was based on the hydrophobicity of the analytes rather than polar group interactions occurring with silica-based stationary phase. CONCLUSIONS: A new, simple and rapid HPLC method for extraction and measurement of DEAE in whole blood or serum samples is reported here.

Effects of epidural steroid injection on pain due to lumbar spinal stenosis or herniated disks: a prospective study.

OBJECTIVES: To describe the extent of pain relief two weeks after an epidural steroid injection in patients with herniated disks and lumbar spinal stenosis, and to identify predictors of changes in pain ratings in each population. METHODS: The study design was a prospective evaluation of patients with lumbar spinal stenosis (LSS) and herniated disks (HDs) referred to a hospital-based pain clinic for an epidural steroid injection (ESI). A complete history, detailed physical examination, comprehensive pain questionnaire, and Brief Symptom Inventory were obtained for all patients. Pain was assessed at baseline and two weeks following a single ESI using a visual analog scale. RESULTS: Two hundred twelve patients (mean age 54 years) were enrolled, and 78 of these provided pain ratings before and two weeks after the injection. LSS patients improved less two weeks following the ESI than HD patients (P = 0.04). Just 38% of LSS patients reported improvement in pain score compared with 61% of HD patients. In analyses that combined LSS and HD patients, predictors of worse response included a report of health problems and a diagnosis of LSS. CONCLUSIONS: LSS patients have worse response to ESIs than HD patients. The poor response to ESI in patients with LSS underscores the need for randomized controlled trials of ESI in this population.

Sphenopalatine ganglion block for the treatment of myofascial pain of the head, neck, and shoulders.

BACKGROUND AND OBJECTIVES: This study examined the effectiveness of sphenopalatine ganglion block (SPGB) for myofascial pain syndrome of the head, neck, and shoulders using a double-blind, placebo-controlled, crossover study design with comparison to an internal standard consisting of trigger point injections (TPI). METHODS: Patients (n = 23) were randomly assigned to receive either: (1) SPGB with 4% lidocaine, then TPI with 1% lidocaine, and finally SPGB with saline placebo or (2) SPGB with saline placebo, then TPI with 1% lidocaine, and finally SPGB with 4% lidocaine. Each respective treatment within each protocol was given sequentially at 1-week intervals for both groups. Prior to the first treatment, all patients assessed their average intensity of pain and pain at that particular moment using a visual analog pain scale. Pain intensity and pain relief were reassessed 30 minutes after each treatment and at 6 hours, 24 hours and 1 week using visual analog pain and pain relief scales. Pain intensity and pain relief data were transformed into natural logarithm units, and the statistical significance of SPGB with 4% lidocaine versus SPGB with placebo, SPGB with 4% lidocaine versus TPI, and TPI versus SPGB with placebo were tested by mixed-model analysis of variance. The magnitude of the differences in pain intensity and pain relief ratings were also compared via computation of 95% confidence intervals. RESULTS: The analgesic effect of SPGB with 4% lidocaine was no better than placebo. Mixed-model analysis of variance revealed improved analgesia with administration of TPIs as compared to SPGB with 4% lidocaine and placebo over the entire week of observations (pain relief scores). CONCLUSIONS: This study suggests that SPGB with 4% lidocaine is no more efficacious than placebo and less efficacious than administration of standard trigger point injections in the treatment of myofascial pain of the head, neck, and shoulders.

Postoperative pain management.

Distressing postoperative pain remains a prevalent problem. Poorly treated pain contributes to patient suffering and may prevent rapid recovery and rehabilitation. An understanding and application of the basic principles of pain management can provide adequate analgesia for the majority of postoperative patients. More advanced methods of pain control can allow excellent relief for virtually all patients but may require the presence of a dedicated pain management service. This article reviews the principles and practice of modern postoperative pain management.

Principles of opioid pharmacotherapy: practical implications of basic mechanisms.

Opioids form the cornerstone of the pharmacologic armamentarium for the treatment of pain. Despite their long history of use, much confusion and misperception still surrounds their use. This short review will focus on pharmacodynamic and physiologic considerations in the clinical use of oral and parenteral opioids.

The analgesic response to intravenous lidocaine in the treatment of neuropathic pain.

This study was performed in order to determine concentration-effect, and graded and quantal dose-response relationships for the clinical administration of intravenous (IV) lidocaine to patients with neuropathic pain. Thirteen patients were administered 500 mg of IV lidocaine at a rate of 8.35 mg/min over 60 min. Visual analog pain scores and venous blood samples were obtained concomitantly at 10 min intervals for 60 min. Blood samples were also obtained for determination of serum and serum water lidocaine concentrations at the onset of analgesia and at the time complete pain relief was attained. Lidocaine concentrations were determined by gas chromatography. Graded dose-response curves were prepared individually and for the group as a whole, and a quantal dose-response curve was prepared for the entire group. The dose-response relationship for IV lidocaine was characterized by large increases in pain relief for concomitant minimal increases in dosage. The difference between the ED50 (372.0 mg) and the ED90 (416.5 mg) was 44.5 mg of lidocaine (5.3 min of infusion). The concentration-effect relationship was also steep with pain scores abruptly decreasing over a range of 0.62 microgram/mL of lidocaine. Interestingly, the free concentration of lidocaine had no better correlation with the onset of analgesia or the attainment of complete analgesia than the serum concentration of lidocaine. This suggests that the mechanism of analgesia to IV lidocaine may not be based upon a conventional concentration-effect relationship. In conclusion, the results of this study suggest that the analgesic response to IV lidocaine is best characterized by a precipitous "break in pain" over a narrow dosage and concentration range.

0.0625% bupivacaine with 0.0002% fentanyl via patient-controlled epidural analgesia for pain of labor and delivery.

OBJECTIVE: To compare the utility of 0.0625% bupivacaine with fentanyl administered via patient-controlled epidural analgesia (PCEA) to a traditional continuous epidural infusion for pain of labor and delivery. DESIGN AND SUBJECTS: Forty-one women in established labor were randomized to receive either (a) 0.0625% bupivacaine with 2 micrograms/ml fentanyl via PCEA (demand dose = 3 ml, lockout interval = 6 min, background infusion = 6 ml/h, no 1 or 4 h limits) or (b) 0.125% bupivacaine with 2 micrograms/ml fentanyl via continuous epidural infusion (CEI) at 12 ml/h. Supplemental 0.25% bupivacaine (3 ml every 5 min, p.r.n., x 3) was administered for treatment of breakthrough pain upon patient request. The study protocol was double-blind and placebo-controlled. OUTCOME MEASURES: Visual analogue pain scores, motor strength, pinprick level of sensory analgesia and bupivacaine use were assessed by an anesthesiologist unaware of the individual patient's randomization to a particular study group. RESULTS: The cephalad extent of pinprick sensory analgesia was significantly lower during both the first (p < 0.03) and second (p < 0.03) stages of labor in patients receiving PCEA. However, visual analogue pain scores, intensity of motor blockade, and need for physician-administered supplemental bupivacaine were comparable in both groups. Patients receiving PCEA used 40% less bupivacaine per hour while achieving analgesia comparable to patients receiving CEI. CONCLUSIONS: The results of this study show that 0.0625% bupivacaine with 2 micrograms/ml of fentanyl is an effective analgesic combination when used via PCEA.

The role of continuous background infusions in patient-controlled epidural analgesia for labor and delivery.

The use of a background infusion with intravenous patient-controlled analgesia (IV-PCA) increases drug consumption without any additional contribution to analgesia. There are no data on the potential advantage of a background infusion administered with patient-controlled epidural analgesia (PCEA) for labor and delivery. Sixty women were randomized to one of four groups and received either: (a) demand dose PCEA (demand dose = 3 mL; lockout interval = 10 min); (b) continuous infusion plus demand dose PCEA (two separate infusion rates: 3 mL/h and 6 mL/h); or (c) a fixed-rate continuous epidural infusion (CEI) at 12 mL/h. All patients received 0.125% bupivacaine with 2 micrograms/mL of fentanyl. The study protocol was double-blind and placebo-controlled. Visual analog pain scores, motor strength, and bilateral pinprick analgesia were assessed every half hour by a blinded observer. Pain scores, cephalad extent of sensory analgesia, and motor block were no different among the study groups during the first and second stages of labor. Cumulative hourly bupivacaine use was similar among all PCEA study groups. However, use of PCEA (in whatever mode) provided a 35% dose-sparing effect in comparison to CEI. The PCEA groups receiving no background infusion or a 3-mL/h background infusion had a greater need for physician-administered supplemental bupivacaine during the first stage of labor. While not statistically significant, a trend toward increased need for supplementation was seen in these same patient groups over the entire course of labor and delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Survey of opioid use in chronic nonmalignant pain patients.

BACKGROUND AND OBJECTIVES: Opioids have been accepted as appropriate treatment for acute and cancer pain, but remain controversial for use with chronic nonmalignant pain. Clinicians are concerned about efficacy, tolerance, addiction, and unwanted side effects. METHODS: The aim of this study was to survey chronic pain patients who were taking opioids for their pain, to determine the incidence of these adverse conditions. Two hundred seventeen patients who were being treated for their pain at two different pain centers completed a medication questionnaire. The most common diagnosis was low back pain. One hundred twelve patients reported taking oral opioids for their pain. RESULTS: Of the patients who reported taking opioids for their chronic pain, 83% felt that the opioids were moderately beneficial in relieving their pain; 25% felt that the opioid had not lost its ability to relieve the pain over time; 35% reported that they did not need to increase their medication; 36% expressed no fear of addiction or dependence; and 56% reported having no unwanted side effects. CONCLUSIONS: The results suggest that chronic nonmalignant pain patients taking opioids for their pain reported some tolerance, fear of addiction, and side effects when taking opioids. However, despite these concerns, some of these patients felt that opioid therapy was very beneficial. Further investigations are needed to determine which patient characteristics predict benefit from opioid therapy for nonmalignant pain.

Regression of sensory anesthesia during continuous epidural infusions of bupivacaine and opioid for total knee replacement.

The epidural administration of morphine and fentanyl delay the regression of sensory anesthesia in postoperative patients receiving epidural bupivacaine. This study was performed to determine any differential effects of two lipid-soluble opioids upon regression of sensory anesthesia during coadministration with epidural bupivacaine. Forty-eight patients scheduled for total knee replacement underwent lumbar epidural catheterization and received 1.5% etidocaine with 1:200,000 epinephrine to establish sensory anesthesia to approximately T6 bilaterally. Patients were randomized by the investigational pharmacy to receive either: (a) bupivacaine without opioid (control) (n = 16), or (b) bupivacaine with 1 mg/mL of meperidine (n = 16), or (c) bupivacaine with 3 micrograms/mL of fentanyl (n = 16) in a double-blind fashion. Intraoperatively, 0.5% bupivacaine +/- opioid was administered by epidural infusion at a rate of 10 mL/h. Postoperatively, the bupivacaine concentration was decreased to 0.25% (+/- the same opioid), and the infusion rate was decreased to 4 mL/h. Pinprick sensory anesthesia and verbal numerical pain score were recorded each hour after surgery by a blinded investigator. For each patient, the study was considered terminated when the cephalad level of sensory anesthesia bilaterally decreased five dermatomal segments or the pain score reached "5" (moderate pain). Patients receiving epidural infusions of bupivacaine and meperidine had a significantly slower regression of sensory anesthesia and slower development of pain. There was no difference in the rate of regression of sensory anesthesia or the development of pain among patients receiving bupivacaine alone or bupivacaine with fentanyl.

Effects of alkalinization of lidocaine on the pain of skin infiltration and intravenous catheterization.

STUDY OBJECTIVE: To test the hypothesis that alkalinization of lidocaine decreases the pain of skin infiltration in surgical patients. DESIGN: Double-blind, randomized, prospective study. SETTING: Preoperative holding units, Brigham and Women's Hospital. PATIENTS: 184 adult surgical patients. INTERVENTIONS: We compared the efficacy of 1% lidocaine with and without 0.1 mEq/ml of sodium bicarbonate (NaHCO3) for relief of pain of (1) skin infiltration and (2) intravenous (i.v.) catheterization prior to surgery. MEASUREMENTS AND MAIN RESULTS: Patients evaluated the intensity of pain using a 100 mm visual analog scale (VAS). There were no differences between study groups (lidocaine with NaHCO3, n = 89; lidocaine alone, n = 95) with respect to site of catheterization or catheter gauge used. Lidocaine plus NaHCO3 caused significantly less pain on skin infiltration (median VAS = 4; range = 0 to 51) than did lidocaine alone (VAS = 8; range = 0 to 48; p < 0.008). Pain of i.v. catheterization also did not differ between groups. There was a weak correlation between catheter gauge and pain of i.v. catheterization (r = -0.19; p = 0.01). CONCLUSIONS: Pain resulting from skin infiltration of lidocaine solutions can be diminished by adding NaHCO3. However, catheter size is more important than the presence or absence of NaHCO3 in determining the pain of i.v. catheterization.