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The effect of preoperative symptom duration (PSD) on patient-reported outcomes (PROs) in anterior cervical discectomy and fusion (ACDF) for radiculopathy is unclear.To determine whether PSD is a predictor for PRO after ACDF for radiculopathy.The Michigan Spine Surgery Improvement Collaborative registry was queried between March, 2014, and July, 2019, for patients who underwent ACDF without myelopathy and PROs (baseline, 90 days, 1 year, 2 years). PROs were measured by numerical rating scales for neck/arm pain, Patient-Reported Outcomes Measurement Information System Short Form-Physical Function (PROMIS-PF), EuroQol-5D (EQ5D), and North American Spine Society satisfaction. Univariate analyses were used to evaluate the proportion of patients reaching minimal clinically important differences (MCID). PSD was3 months, 3 month-1 year, or1 years. Multiple logistic regression models were used to estimate the association between PSD and PRO reaching MCID. The discriminative ability of the model was evaluated by receiver operating characteristic curve.We included 2233 patients who underwent ACDF with PSD3 months (278, 12.4%), 3 month-1 year (669, 30%), and1 years (1286, 57.6%). Univariate analyses demonstrated a greater proportion of patients achieving MCID in3-month cohort for arm numerical rating scales, PROMIS-PF, EQ5D, and North American Spine Society Satisfaction. Multivariable analyses demonstrated using3 months PSD as a reference, PSD1 years was associated with decreased odds of achieving MCID for EQ5D (odds ratio 0.5, CI 0.32-0.80, P = .004). Private insurance and increased baseline PRO were associated with significantly higher odds for achieving PROMIS-PF MCID and EQ5D-MCID.Preoperative symptom duration greater than 1 year in patients who underwent ACDF for radiculopathy was associated with worse odds of achieving MCID for multiple PROs.

STUDY DESIGN Retrospective review of prospectively collected data at a single institution. OBJECTIVE To compare perioperative and clinical outcomes in morbidly obese patients who underwent minimally invasive transforaminal lumbar interbody fusion (MiTLIF). SUMMARY OF BACKGROUND DATA Obesity remains a serious public health concern. Obese patients who undergo lumbar fusion have historically thought to be at higher risk for complications and fare worse regarding quality-of-life outcomes. However, recent literature may demonstrate comparable risk and outcomes in obese patients. An increasing number of patients are categorized as morbidly obese (body mass index [BMI] ≥ 40 kg/m2). Perioperative and patient-reported outcomes (PROs) are lacking in this patient population. METHODS The authors retrospectively reviewed a prospectively collected database of all morbidly obese and non-obese patients that underwent MiTLIF between 2015 and 2018 for degenerative conditions who had minimum 1-year follow-up for outcome assessment. An inverse propensity/probability of treatment weighting was utilized to create a synthetic weighted sample in which covariates were independent of obesity designation to adjust for imbalance between groups. Generalized estimating equations (GEE) was used to estimate the association of morbid obesity and complications and 1-year PROs. RESULTS A total of 292 patients were analyzed with 234 non-obese patients and 58 morbidly obese patients. Multivariate analysis failed to demonstrate any association between morbid obesity and achieving minimal clinically important difference (MCID) for Oswestry disability index (ODI), visual analog scale (VAS), or short form-12 (SF-12) physical component score. However, morbid obesity was associated with significant decrease in odds of achieving MCID for SF-12 mental component score (P = 0.001). Increased surgery duration was significantly associated with morbid obesity (P = 0.001). Morbid obesity exhibited no statistically significant association with postoperative complications, readmission, pseudarthrosis, or adjacent segment disease (ASD). CONCLUSION Morbidly obese patients who undergo MiTLIF can achieve meaningful clinical improvement comparable to nonobese patients. Morbid obesity was associated with longer surgical times but was not associated with postoperative complications, readmission, or ASD.Level of Evidence: 3.

STUDY DESIGN Retrospective review of a multi-institutional data registry. OBJECTIVE The authors sought to determine the association between age and complications & patient-reported outcomes (PRO) in patients undergoing multilevel transforaminal interbody lumbar fusion (MTLIF). SUMMARY OF BACKGROUND DATA Elderly patients undergoing MTLIF are considered high risk. However, data on complications and PRO are lacking. Additionally, safety of multilevel lumbar fusion in the elderly remains uncertain. METHODS Patients ≥50-year-old who underwent MTLIF for degenerative lumbar spine conditions were analyzed. Ninety-day complications and PROs (baseline, 90-d, 1-y, 2-y) were queried using the MSSIC database. PROs were measured by back & leg visual analog scale (VAS), Patient-reported Outcomes Measurement Information System (PROMIS), EuroQol-5D (EQ-5D), and North American Spine Society (NASS) Patient Satisfaction Index. Univariate analyses were used to compare among elderly and complication cohorts. Generalized estimating equation (GEE) was used to identify predictors of complications and PROs. RESULTS A total of 3120 patients analyzed with 961 (31%) ≥ 70-y-o and 2159 (69%) between 50-69. A higher proportion of elderly experienced postoperative complications (P = .003) including urinary retention (P =

The current International Association for the Study of Pain (IASP) definition of pain as "An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage" was recommended by the Subcommittee on Taxonomy and adopted by the IASP Council in 1979. This definition has become accepted widely by health care professionals and researchers in the pain field and adopted by several professional, governmental, and nongovernmental organizations, including the World Health Organization. In recent years, some in the field have reasoned that advances in our understanding of pain warrant a reevaluation of the definition and have proposed modifications. Therefore, in 2018, the IASP formed a 14-member, multinational Presidential Task Force comprising individuals with broad expertise in clinical and basic science related to pain, to evaluate the current definition and accompanying note and recommend whether they should be retained or changed. This review provides a synopsis of the critical concepts, the analysis of comments from the IASP membership and public, and the committee's final recommendations for revisions to the definition and notes, which were discussed over a 2-year period. The task force ultimately recommended that the definition of pain be revised to "An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage," and that the accompanying notes be updated to a bulleted list that included the etymology. The revised definition and notes were unanimously accepted by the IASP Council early this year.

STUDY DESIGN Retrospective analysis of prospectively collected registry data using multivariable analyses of imputed data. OBJECTIVE We sought to demonstrate that age would not be associated with complications in patients undergoing anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA Elderly patients (≥70 yrs) undergoing ACDF are considered a higher risk for complications. However, conclusive evidence is lacking. The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a quality improvement collaborative with 30 hospitals across Michigan. METHODS The study included all patients who had 1 to 4 level ACDF (September 2015-August 2019) for 90-day complications. Major and minor complications were defined using a validated classification. Multiple imputations were used to generate complete covariate datasets. Generalized estimating equation model was used to identify associations with complications using the whole cohort and elderly subgroup analyses. Bonferroni correction was used. RESULTS Nine thousand one hundred thirty five patients (11.1% ≥ 70 yrs and 88.9%

Recognizing that electrically stimulating the motor cortex could relieve chronic pain sparked development of noninvasive technologies. In transcranial magnetic stimulation (TMS), electromagnetic coils held against the scalp influence underlying cortical firing. Multiday repetitive transcranial magnetic stimulation (rTMS) can induce long-lasting, potentially therapeutic brain plasticity. Nearby ferromagnetic or electronic implants are contraindications. Adverse effects are minimal, primarily headaches. Single provoked seizures are very rare. Transcranial magnetic stimulation devices are marketed for depression and migraine in the United States and for various indications elsewhere. Although multiple studies report that high-frequency rTMS of the motor cortex reduces neuropathic pain, their quality has been insufficient to support Food and Drug Administration application. Harvard's Radcliffe Institute therefore sponsored a workshop to solicit advice from experts in TMS, pain research, and clinical trials. They recommended that researchers standardize and document all TMS parameters and improve strategies for sham and double blinding. Subjects should have common well-characterized pain conditions amenable to motor cortex rTMS and studies should be adequately powered. They recommended standardized assessment tools (eg, NIH's PROMIS) plus validated condition-specific instruments and consensus-recommended metrics (eg, IMMPACT). Outcomes should include pain intensity and qualities, patient and clinician impression of change, and proportions achieving 30% and 50% pain relief. Secondary outcomes could include function, mood, sleep, and/or quality of life. Minimum required elements include sample sources, sizes, and demographics, recruitment methods, inclusion and exclusion criteria, baseline and posttreatment means and SD, adverse effects, safety concerns, discontinuations, and medication-usage records. Outcomes should be monitored for at least 3 months after initiation with prespecified statistical analyses. Multigroup collaborations or registry studies may be needed for pivotal trials.

BACKGROUND Injectable formulations of diclofenac have long been available in Europe and other countries. These formulations use a default dose of 75 mg of diclofenac delivered IV over 30 to 120 minutes or as an IM injection. A novel formulation of injectable diclofenac sodium, Dyloject®, is solubilized with hydroxypropyl β-cyclodextrin (HPβCD) so that it can be given IV or IM in a small volume bolus. In this multicenter, multiple-dose, multiple-day, randomized, double-blind, parallel-group phase 3 study, we investigated whether lower doses of HPβCD diclofenac delivered as a small volume bolus would be effective for the management of acute pain after abdominal or pelvic surgery. METHODS Adults with moderate and severe pain, defined as ≥50 mm on a 0 to 100 mm visual analog scale, within 6 hours after surgery were randomly assigned (1:1:1:1 ratio) to receive HPβCD diclofenac, 18.75 mg or 37.5 mg; ketorolac tromethamine 30 mg; or placebo. Patients in all treatment arms received a bolus IV injection every 6 hours until discharged. They were observed for at least 48 h, and for up to 5 days. Rescue IV morphine was available any time, up to a total of 7.5 mg over a 3-hour period. The primary efficacy measure was the sum of pain intensity differences from 0 to 48 hours after study drug initiation. RESULTS Three hundred thirty-one patients received ≥1 dose of study drug. Over the first 48 hours, both IV HPβCD diclofenac doses, as well as ketorolac, produced significant reductions in pain intensity over placebo (all P < 0.05), as well as significant reductions in the need for rescue morphine administration. Both doses of HPβCD diclofenac, as well as ketorolac, significantly reduced rescue morphine dosages, as compared to placebo (P < 0.0001), and time to rescue morphine administration was significantly increased by treatment with 18.75 mg diclofenac and ketorolac. The overall incidence of treatment-related adverse events was 20.2%. No treatment-related serious adverse events were reported in either diclofenac dose group, whereas only 1 was reported in the ketorolac group. CONCLUSIONS For patients with acute moderate and severe pain after abdominal or pelvic surgery, repeated 18.75 mg and 37.5 mg doses of HPβCD diclofenac provided significant analgesic efficacy, as compared to placebo. Significant analgesic efficacy was also provided by the active comparator ketorolac. Both HPβCD diclofenac and ketorolac significantly reduced the need for opioids.

BACKGROUND: Improving perioperative efficiency and throughput has become increasingly important in the modern practice of anesthesiology. Fast-track surgery represents a multidisciplinary approach to improving perioperative efficiency by facilitating recovery after both minor (i.e., outpatient) and major (inpatient) surgery procedures. In this article we focus on the expanding role of the anesthesiologist in fast-track surgery. METHODS: A multidisciplinary group of clinical investigators met at McGill University in the Fall of 2005 to discuss current anesthetic and surgical practices directed at improving the postoperative recovery process. A subgroup of the attendees at this conference was assigned the task of reviewing the peer-reviewed literature on this topic as it related to the role of the anesthesiologist as a perioperative physician. RESULTS: Anesthesiologists as perioperative physicians play a key role in fast-track surgery through their choice of preoperative medication, anesthetics and techniques, use of prophylactic drugs to minimize side effects (e.g., pain, nausea and vomiting, dizziness), as well as the administration of adjunctive drugs to maintain major organ system function during and after surgery. CONCLUSION: The decisions of the anesthesiologist as a key perioperative physician are of critical importance to the surgical care team in developing a successful fast-track surgery program. (Anesth Analg 2007;104:1380‐96)

We reviewed randomized controlled trials to determine the efficacy and safety of systemically administered local anesthetics compared with placebo or active drugs. Of 41 retrieved studies, 27 trials of diverse quality were included in the systematic review. Ten lidocaine and nine mexiletine trials had data suitable for meta-analysis (n = 706 patients total). Lidocaine (most commonly 5 mg/kg IV over 30-60 min) and mexiletine (median dose, 600 mg daily) were superior to placebo (weighted mean difference on a 0-100 mm pain intensity visual analog scale = -10.60; 95% confidence interval: -14.52 to -6.68; P < 0.00001) and equal to morphine, gabapentin, amitriptyline, and amantadine (weighted mean difference = -0.60; 95% confidence interval: -6.96 to 5.75) for neuropathic pain. The therapeutic benefit was more consistent for peripheral pain (trauma, diabetes) and central pain. The most common adverse effects of lidocaine and mexiletine were drowsiness, fatigue, nausea, and dizziness. The adverse event rate for systemically administered local anesthetics was more than for placebo but equivalent to morphine, amitriptyline, or gabapentin (odds ratio: 1.23; 95% confidence interval: 0.22 to 6.90). Lidocaine and mexiletine produced no major adverse events in controlled clinical trials, were superior to placebo to relieve neuropathic pain, and were as effective as other analgesics used for this condition.

Background Meta-analyses report similar numbers needed to treat for nonsteroidal antiinflammatory drugs (NSAIDs) and opioids. Differences in baseline pain intensity among the studies from which these numbers needed to treat were derived may have confounded the results. NSAIDs have an opioid-sparing effect, but the importance of this effect is unclear. Therefore, the authors sought to compare the proportions of subjects who obtain pain relief with ketorolac versus morphine after surgery and to determine whether the opioid-sparing effect of an NSAID reduces the magnitude of opioid side effects. Methods The study was a double-blind, randomized controlled trial. The authors randomly assigned 1,003 adult patients to receive 30 mg ketorolac or 0.1 mg/kg morphine intravenously. They calculated the proportion of subjects who achieved at least 50% reduction in pain intensity 30 min after analgesic administration. Further, so long as pain intensity 30 min after analgesic administration was 5 or more out of 10, patients received 2.5 mg morphine every 10 min until pain intensity was 4 or less out of 10. The authors assessed the presence of opioid-related side effects. Results Five hundred patients received morphine and 503 received ketorolac. Fifty percent of patients in the morphine group achieved pain relief, compared with 31% in the ketorolac group (difference, 19%; 95% confidence interval, 13-25%). The ketorolac-morphine group required less morphine (difference, 6.5 mg; 95% confidence interval, -5.8 to -7.2) and had a lower incidence of side effects (difference, 11%; 95% confidence interval, 5-16%) than the morphine group. Conclusions Opioids are more efficacious analgesics than NSAIDs, although historic data for these two drugs yield similar numbers needed to treat. Adding NSAIDs to the opioid treatment reduces morphine requirements and opioid-related side effects in the early postoperative period.

Few placebo-controlled trials have investigated the treatment of breakthrough pain (BTP) in patients with chronic pain. We evaluated the efficacy and safety of intranasal ketamine for BTP in a randomized, double-blind, placebo-controlled, crossover trial. Twenty patients with chronic pain and at least two spontaneous BTP episodes daily self-administered up to five doses of intranasal ketamine or placebo at the onset of a spontaneous BTP episode (pain intensity > or =5 on a 0-10 scale). Two BTP episodes at least 48 h apart were treated with either ketamine or placebo. Patients reported significantly lower BTP intensity following intranasal ketamine than after placebo (P < 0.0001) with pain relief within 10 min of dosing and lasting for up to 60 min. No patient in the ketamine group required his/her usual rescue medication to treat the BTP episode, while seven out of 20 (35%) patients in placebo group did (P = 0.0135). Intranasal ketamine was well tolerated with no serious adverse events. After ketamine administration, four patients reported a transient change in taste, one patient reported rhinorrhea, one patient reported nasal passage irritation, and two patients experienced transient elevation in blood pressure. A side effect questionnaire administered 60 min and 24 h after drug or placebo administration elicited no reports of auditory or visual hallucinations. These data suggest that intranasal administration of ketamine provides rapid, safe and effective relief for BTP.

Living liver donors for adult liver transplant recipients undergo extensive liver resection. Partial donor hepatectomies may alter postoperative drug metabolism and hemostasis; thus, the risks and the benefits of pain management for this unique patient population may need to be reassessed. The safety and efficacy of combined epidural analgesia and field infiltration in our initial living liver donor group are presented. A thoracic epidural catheter was placed before general anesthesia in 2 female and 6 male donors (44.2 +/- 11.3 years old, mean +/- standard deviation [SD], range 26-56). At the end of surgery, incisions were infiltrated (bupivacaine 0.25%), and an epidural infusion was used (bupivacaine 0.1% + hydromorphone hydrochloride 0.02%). Clinical outcomes were followed for 5 days. The time sequence of pain intensity on a 0-10 visual analog scale clustered into 3 phases, the intensity of which differed significantly from each other (2.2 +/- 0.6, 0.69 +/- 0.2, and 2.37 +/- 0.3 respectively, P = 0.028). Right shoulder pain was observed in 75% of the donors. Sedation, pruritus, and nausea were minimal. Consistently maximal international normalized ratio elevation occurred at 17.6 +/- 7 hours postoperatively, then slowly declined. Platelet counts were lowest on day 3. No neurologic injury or local anesthetic toxicity was observed. This 2-site approach provided effective, safe, postoperative analgesia for our donors. Universally, coagulopathy ensued, indicating a potentially increased risk for epidural hemorrhage at epidural catheter removal and mandating close postoperative neurologic and laboratory monitoring. Research is needed to advance the understanding of postoperative coagulopathy and hepatic dysfunction in these donors to further optimize their perioperative management, including that of analgesia.

Ultralow doses of naloxone (0.001-0.1 microg/kg) produce analgesia in animal models. However, no clinical study has evaluated the combination of ultralow dose naloxone and morphine using patient-controlled analgesia (PCA). This randomized, double blind controlled study sought to determine if the combination of ultralow dose naloxone and morphine in PCA solutions affects opioid requirements, analgesia, and side effects. Two-hundred and sixty-five patients (18-65 years old) undergoing operations were randomized to receive PCA morphine 1 mg/ml (n=129) or PCA morphine 1 mg/ml plus naloxone 0.6 microg/ml (n=136). We evaluated the numbers of supplemental rescue doses, the cumulative dose of each PCA solution, pain intensity, pain relief, and opioid side effects during the first 24 h after surgery. We found that opioid requirements did not differ significantly between groups. The morphine+naloxone group on average required 0.07 mg more morphine (95% CI -1.1 to 1.3) during the 24 h than the morphine group. Pain intensity levels were also similar in both groups. The morphine+naloxone group had 0.06 units lower (95% CI -0.5 to 0.4) pain intensity levels than the morphine group. The morphine+naloxone group had a lower incidence of nausea and pruritus than the morphine group (P=0.01 for both symptoms). However, the incidence of vomiting, time to tolerate fluids, sedation, and urinary retention were similar between groups (all P values >0.1). The combination of ultralow dose naloxone and morphine in PCA does not affect analgesia or opioid requirements, but it decreases the incidence of nausea and pruritus.

To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of data, encourage more complete reporting of outcomes, simplify the preparation and review of research proposals and manuscripts, and allow clinicians to make informed decisions regarding the risks and benefits of treatment.Under the auspices of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT), 27 specialists from academia, governmental agencies, and the pharmaceutical industry participated in a consensus meeting and identified core outcome domains that should be considered in clinical trials of treatments for chronic pain.There was a consensus that chronic pain clinical trials should assess outcomes representing six core domains: (1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events, (6) participant disposition (e.g. adherence to the treatment regimen and reasons for premature withdrawal from the trial). Although consideration should be given to the assessment of each of these domains, there may be exceptions to the general recommendation to include all of these domains in chronic pain trials. When this occurs, the rationale for not including domains should be provided. It is not the intention of these recommendations that assessment of the core domains should be considered a requirement for approval of product applications by regulatory agencies or that a treatment must demonstrate statistically significant effects for all of the relevant core domains to establish evidence of its efficacy.

Study design Cross-sectional study of 63 patients with chronic low back pain (CLBP). Objectives To determine the relationship between the SF-36 physical functioning (PF) scale and physical performance on a modified symptom limited treadmill test, and to determine the effect of disability status and SF-36 mental health (MH) scores on self-reported physical functioning and on physical performance. Summary of background data Patients with CLBP report low levels of physical functioning. Because self-report measures are influenced by psychosocial factors, such as disability and low MH, a common recommendation is to supplement self-report with objective or physical performance testing. Little information exists regarding whether performance testing is also influenced by disability and low MH. Materials and methods Patients completed the SF-36 and performed a maximal, symptom-limited, modified treadmill test. Total walking time and heart rate on the treadmill were registered. The effects of disability and low MH on self-report and performance testing were calculated by unpaired Student's t-testing and effect size estimation. Results A strong relationship between the PF scale of the SF-36 and treadmill walking time was found, but there was little evidence of overlap between these physical functioning domains. Both disability status and low MH had a much larger effect on self-report measures than on physical performance. Conclusions Self-report measurements and performance-based assessments provide information about distinct, although related, domains of physical functioning. Disability and low MH are associated with lower SF-36 PF scores. Our results confirm that self-report measures require supplementation with objective performance testing to provide optimal assessment for patients with CLBP.

Despite widespread use of the 0-10 numeric rating scale (NRS) of pain intensity, relatively little is known about the meaning of decreases in pain intensity assessed by means of this scale to patients. We aimed to establish the meaning to patients of declines in pain intensity and percent pain reduction. Upon arrival to the postanesthesia care unit, postsurgical patients rated their baseline pain intensity on both a 0-10 NRS and on a 4-point verbal scale. Patients whose NRS was higher than 4/10 received intravenous opioids until their pain intensity declined to 4/10 or lower. During opioid titration, patients were asked every 10 min to rate pain intensity on a NRS and to indicate the degree of pain improvement on a 5-point Likert scale from 'no improvement' to 'complete pain relief'. Seven hundred adult patients were enrolled. For patients with moderate pain, a decrease of 1.3 units (20% reduction) corresponded to 'minimal' improvement, a decrease of 2.4 (35% reduction) to 'much' improvement, a decrease of 3.5 units (45% reduction) corresponded to 'very much' improvement. For patients with severe pain, the decrease in NRS pain score and the percentage of pain relief had to be larger to obtain similar degrees of pain relief. The change in pain intensity that is meaningful to patients increases as the severity of their baseline pain increases. The present findings are applicable in the clinical setting and research arena to assess treatment efficacy.

Objective There is growing controversy on the value of blocking the sympathetic nervous system for the treatment of complex regional pain syndromes (CRPS). The authors sought to evaluate the efficacy of sympathetic blockade with local anesthetic in these syndromes. In addition, they performed a comprehensive review of the pathophysiology and other treatments for CRPS. Design Systematic review of the literature was performed. MEDLINE was searched from 1966 through 1999. The authors identified only three randomized controlled trials (RCTs) that evaluated sympathetic blockade with local anesthetic, but because of differences in study design they were unable to pool the study data. The authors therefore included nonrandomized studies and case series. Interventions Studies were included if local anesthetic sympathetic blockade was used in at least 10 patients. Studies were excluded if continuous infusion techniques, somatic nerve blocks, or combined sympatholytic therapies were evaluated. Outcome measures Pain relief was classified as full, partial, or absent. The lack of a comparison group in the studies allowed only the calculation of distribution of the response categories, and the sum of the pooled rates does not equal 100%. Results Twenty-nine studies were included that evaluated 1,144 patients. Nineteen studies were retrospective, 5 prospective case series, 3 RCTs, and 2 nonrandomized controlled studies. The quality of the publications was generally poor. Twenty-nine percent of patients had full response, 41% had partial response, and 32% had absent response. It was not possible to estimate the duration of pain relief. Conclusions This review raises questions as to the efficacy of local anesthetic sympathetic blockade as treatment of CRPS. Its efficacy is based mainly on case series. Less than one third of patients obtained full pain relief. The absence of control groups in case series leads to an overestimation of the treatment response that can explain the findings.

The continuous infusion of low doses of naloxone has been reported to decrease postoperative opioid requirements and opioid side effects. However, there is no study that evaluates the effectiveness of the combination of a low dose of naloxone and morphine using patient-controlled analgesia (PCA). This prospective, randomized double-blind controlled study sought to determine if the combination of a low dose of naloxone and morphine in a PCA solution decreases postoperative opioid requirements and pain intensity. One hundred sixty-six patients (18-65 years old) undergoing operations of less than 3 h duration with an American Society of Anesthesiologist physical status I or II were randomized to receive PCA morphine 1 mg/cc plus normal saline or PCA morphine 1 mg/cc plus naloxone 6 microg/cc. Initial PCA settings were 0.5 cc per demand with a lockout time of 10 min. The numbers of 2.5 cc supplemental rescue doses and the cumulative dose of each solution were recorded in the first 24 h after the surgical procedure. Pain intensity and opioid side effects were evaluated every 10 min in the post-anesthesia care unit and every 4 h afterwards. Patient satisfaction was assessed at the end of the 24 h of observation. The morphine+naloxone group had more treatment failures (P=0.0001), higher opioid requirements (P=0.0097), greater pain intensity (P=0.04), less pain relief (P=0.004), and less satisfaction (P=0.01) than the morphine group. The incidence of side effects was similar in both groups (P=0.3). Contrary to previous reports, adding low doses of naloxone to a morphine PCA solution increases opioid requirements and pain.

Study Design. A cross-sectional study. Objectives. To determine the relative contribution of pain increase and mental health to testing performance during a single bout of exercise in patients with chronic low back pain. Background. Controversy exists as to which factors principally limit physical performance in patients with chronic low back pain. Some believe psychological factors limit physical performance, whereas others believe activity-related increases in pain intensity limit performance. Methods. Seventy-five patients with chronic low back pain reported pain intensity before and after undergoing a maximal, symptom-limited modified treadmill test. Walking time (in minutes) and aerobic fitness were measured. The Short Form 36 Health Survey was administered to all patients, Results. Filty-four percent of the sample stopped testing because of a significant increase in pain intensity (P = 0.0001). Treadmill performance was lower in patients who stopped because of pain than in those who stopped because of fatigue (P = 0.02). The patients who stopped because of pain were also more likely to have low mental health as assessed by the Short Form 36 Health Survey. Low mental health, however, did not have a statistically significant influence on treadmill performance. Conclusion. The data indicate that impairment of physical performance during treadmill testing in patients with chronic low back pain is attributable to testing-induced increase in pain intensity rather than to individual low mental health scores.

Recent animal models of experimental nerve injury have proven useful in evaluating potential sympathetic involvement in neuropathic pain syndromes. We have employed a widely adopted unilateral L 5 /L 6 spinal nerve ligation model to compare the development of mechanical allodynia with neurochemical changes both at the site of peripheral nerve injury and in the dorsal root ganglia (DRG). We have focused on the expression of neuropeptide Y (NPY), a well-studied regulatory peptide and phenotypic marker of sympathetic neurons, and functionally related Y-receptor binding sites following nerve injury. In sympathetic neurons, NPY is colocalized and coreleased with norepinephrine (NE) at peripheral sites of action. Furthermore, NPY gene expression is induced within the population of medium- and large-diameter DRG neurons of the A β -fiber class after experimental nerve injury. We therefore hypothesized that concurrent alterations in NPY and NE expression by sympathetic and sensory neurons may be a contributing factor to sympathetically-maintained neuropathic conditions. Animals with unilateral L 5 /L 6 spinal nerve ligation developed mechanical allodynia of the hind paw ipsilateral to the site of injury that persisted until sacrifice at postoperative day 10. A significant induction of preproneuropeptide Y-encoding (PPNPY) mRNA, as detected by in situ hybridization histochemistry (ISHH), occurred in populations of medium- and large-diameter DRG neurons ipsilateral to the site of injury. Immunohistochemical analysis indicated a marked decline in the number of labeled sympathetic axons positive for tyrosine hydroxylase-like and NPY-like immunoreactivities (TH-Ll and NPY-LI, respectively) proximal to the site of nerve injury and almost complete elimination of immunopositive fibers distal to the site of ligation. Whereas, the extent of colocalization of NPY-LI to TH-LI-positive sympathetic axons in unaffected L 4 or L 5 nerve segments exceeded 80%, this figure declined to approximately 50% in regenerating axons of ligated spinal nerve L 5 . The portion of NPY-LI that was not colocalized to sympathetic TH-LI-positive fibers was most likely contributed by regenerating sensory axons, consistent with marked de novo synthesis of NPY by DRG neurons. In end bulb axon terminals, i.e. morphological profiles characteristic of neuromas, NPY-LI-positive elements that were not colocalized to TH-LI-positive sympathetic elements appeared to be spatially segregated from those of sympathetic origin with colocalized TH-LI and NPY-LI. Receptor autoradiography indicated that small- and medium-diameter DRG somata of the C-fiber class normally express both Y 1 and Y 2 receptor subtypes. The pattern of the distribution of Y-receptor binding sites appeared to be relatively unaffected by spinal nerve ligation. In contrast, there was a marked increase in the density of Y 2 receptor binding sites in the proximal segment of ligated spinal nerve L 5 , consistent with previously published data indicating differential transport of the Y 2 autoregulatory receptor subtype to nerve terminals. Induction of NPY gene expression in injured DRG neurons is consistent with appearance of NPY-LI-positive end bulbs derived from regenerating sensory axons that are found in developing neuromas containing a relatively high density of transported prejunctional Y 2 receptors. Newly established functional interactions of spatially segregated sensory- and sympathetically-derived end bulbs in developing neuromas may enhance neuronal hyperexcitability engendered by aberrant electrical activity at the site of injury. Injury-related alterations in the regulatory activities of NPY released within the DRG at somally-distributed Y-receptors may also contribute to the development and/or persistence of symptoms characteristic of sympathetically-maintained pain. Finally, at later times NPY-mediated modulation of NE release from invading sympathetic axon terminals within the DRG may affect the extent of α 2 receptor-mediated neuronal hyperexcitability associated with neuropathic pain.

OBJECTIVE To evaluate the hemodynamic effects of intravenous somatostatin administration in patients during the early postoperative period. DESIGN Prospective, case-controlled trial. SETTING Postanesthesia care unit. PATIENTS Ten postoperative, noncirrhotic, American Society of Anesthesiologists physical status II patients, after resection of nonsecretory (i.e., non-neuroendocrine) tumors. No patient received any vasoactive medication perioperatively. INTERVENTIONS Three hours after the end of surgery, normal saline or somatostatin was intravenously administered in two phases: a) in phase 1, patients received a 20-mL bolus of normal saline within 1 min, followed by a continuous infusion of 20 mL of normal saline for the next 30 mins. Patients were left undisturbed for the subsequent 30 mins. b) in phase 2, patients received somatostatin (3.5 micrograms/kg, 20-mL bolus) over 1 min, followed by a continuous infusion of somatostatin (3.5 micrograms/kg/hr) for 72 hrs. MEASUREMENTS AND MAIN RESULTS Anesthesia was managed according to a prospectively designed protocol. Patients' hemodynamic profiles and pressure waveforms were recorded immediately before the bolus injections of normal saline and somatostatin, and at every minute thereafter for 30 mins. Bolus doses of somatostatin produced a transient, nonsignificant decrease in heart rate, along with short-lived increases in systolic arterial pressure, diastolic arterial pressure, systolic pulmonary arterial pressure, diastolic pulmonary arterial pressure, and central venous pressure. CONCLUSION Bolus intravenous somatostatin administered postoperatively after tumor resection in patients produced transient cardiovascular changes that were not sustained during a subsequent continuous infusion.

We performed a meta-analysis of the efficacy and safety of neurolytic celiac plexus block (NCPB) for cancer pain. A literature search yielded 59 papers, but data on NCPB in two or more patients was available in only 24 papers. Twenty-one studies were retrospective, one was prospective, and two were randomized and controlled. Cancer type was stated in 1117 of 1145 patients reported (63% pancreatic, 37% nonpancreatic). A bilateral posterior approach with 15-50 mL [corrected] of 50%-100% alcohol was the most common technique. Nonradiologically guided NCPB was performed in 246 patients (32%); guidance was by computed tomography (CT) in 214 (28%), radiograph in 271 (34%), fluoroscopy in 36 (5%), or ultrasound in 7 (< 1%). Good to excellent pain relief was reported in 878/989 patients (89%) during the first 2 wk after NCPB. Long-term followup beyond 3 mo revealed persistent benefit. Partial to complete pain relief continued in approximately 90% of patients alive at 3 mo post-NCPB and in 70%-90% until death even if beyond 3 mo post-NCPB. Patients with pancreatic cancer responded similarly to those with other intraabdominal malignancies. Common adverse effects were transient, including local pain (96%), diarrhea (44%), and hypotension (38%); complications occurred in 2%. This analysis suggests that: 1) NCPB has long-lasting benefit for 70%-90% of patients with pancreatic and other intraabdominal cancers, regardless of the technique used; 2) adverse effects are common but transient and mild; and 3) severe adverse effects are uncommon.

To determine the level of pain that acutely burned children experience, we obtained pain scores before, during and after burn dressing change (BDC). Pain scores were higher during the BDC, consistent with severe pain during this procedure. A positive correlation between pain scores and the body surface area (BSA) burned suggests that pain increases with the size of the burn. Contrary to widely held beliefs, comparison of mean pain scores and the percent of 3rd degree burn revealed that the larger the area of full-thickness injury, the greater the pain. Regardless of wide variations in patient characteristics, fixed doses of oral narcotics were usually prescribed for pain. Patients with BSA greater than 70% experienced severe pain during BDC despite the type, dose or route of opioids. These findings suggest the need for (a) education to correct the myth that 'third-degree burns don't hurt'; (b) revision of analgesic prescribing patterns in the burned child; and (c) research to determine the mechanisms (e.g., tolerance or deafferentation) underlying the opioid-resistant nature of pain after large burns.

Tibial plateau fractures are frequently associated with ligamentous and meniscal injuries. The traditional method of evaluating these injuries for open surgery does not take into account the soft tissue component. When there is not extensive displacement of the fracture fragments, the goal of articular reconstruction and soft tissue repair can be achieved arthroscopically. Arthroscopic surgery is performed; all compartments of the knee are examined, and the articular surface is reduced, either with a probe in the joint or below through a transosseus window. Bone grafting is performed when necessary. The soft tissues are then repaired. Good results have been achieved with this method in selected cases.

The purpose of this study was to use citation analysis to identify major themes and contributors to the pain and analgesia literature over the past two decades. A citation analysis was performed on a database of more than 110,000 articles in the biomedical literature from January 1981 through June 1997, and in the interval from January 1988 through June 1997. Articles and authors related to pain and analgesia research and practice were identified by searching approximately 7,700 journals. The 20 articles and 20 authors with the most citations were then checked by hand to ensure relevance to pain or analgesia. Most of the high-impact articles identified pertained to research on basic pain pathways. Nearly all the articles concerned opioids, nonsteroidal antiinflammatory drugs, and consequences of analgesic use. None of the highest-impact articles address assessment of clinical pain. Few women were first authors of any most frequently cited paper. Citation analysis is a useful tool in identifying important contributions to the biomedical literature. Recent and continuing research trends include the use of nonsteroidal antiinflammatory drugs, opioid mechanisms, and persistent pain disorders. Current trends expected to become stronger include description of pain from the patient's perspective and mechanisms of the transition from acute to chronic pain.We performed a citation analysis to identify important contributions and contributors to the biomedical literature. Recent pain and analgesia research has been focused on mechanisms of pain, but evidence suggests the importance of understanding the pain experience from the patient's perspective and the transition from acute to chronic pain.