Myiasis in Neglected Cutaneous Squamous Cell Carcinoma of the Head and Neck: Review of Management and Current Protocol Recommendations.

OBJECTIVE: To propose a first-aid management protocol for myiasis in neglected cutaneous squamous cell carcinoma (SCC) in the ED based on a recent literature review. DATA SOURCES: PubMed. STUDY SELECTION: Inclusion criteria were all series and case reports of primary/secondary cutaneous SCC with myiasis of the head and neck, including orbital SCC cases, published after 2005. DATA EXTRACTION: A total of 14 articles including 15 patients were included. DATA SYNTHESIS: Demographics, socioeconomic situation, site of the lesion, larvae species with bacterial suprainfection, and first-aid treatment options were discussed. Two representative cases are described. CONCLUSIONS: Large, ulcerated, necrotic, myiasis-burdened SCC lesions in the head and neck area present a challenge for treatment, and to date, no consensus regarding first-aid management exists. The authors' proposed four-pillar first-aid management scheme may be a valid option to rapidly improve wound condition through disinfection, pain relief, and malodor and discharge eradication as a bridge to surgery.

Clinical analgesia correlates with decline in temporal summation in response to remifentanil infusion in patients with chronic neuropathic (radicular) pain.

BACKGROUND: Animal studies have shown that in addition to their antinociceptive effects, opioids have attenuated the electrophysiological "wind-up" phenomenon. Although effects of opioids on clinical pain and on temporal summation (TS), the human correlatives of this phenomenon, have been tested repeatedly, correlations between these two parameters have not been reported so far. OBJECTIVES: To search for possible correlations between the effects of remifentanil on clinical pain intensity and on the magnitude of TS in patients with chronic pain. DESIGN: A single-blinded prospective study. SETTING: A tertiary care pain clinic. PATIENTS: Thirty-one patients (24 men) with chronic lumbar (radicular) neuropathic pain. INTERVENTION: Intervenous administration of saline followed by remifentanil infusions. MAIN OUTCOME MEASURES: Clinical pain intensity and thermal TS measured at baseline, during infusion of each drug and 20 minutes after termination of remifentnail infusion. RESULTS: Friedman test revealed statistically significant differences in the magnitudes of both clinical pain intensity and TS (x(2(3)) = 73, p < 0.001 and x(2(3)) = 11.38, p = 0.01, respectively). Post hoc analysis (Wilcoxon signed-rank test) showed significant differences between clinical pain intensities measured at all time points but significant reductions in the magnitudes of TS were found only during remifentanil compared to baseline (p = 0.014) and to saline (p = 0.019). The difference in clinical pain between saline and remifentanil positively correlated with the difference in TS measured at the same time points (Spearman's test; r = 0.444, p = 0.012). CONCLUSIONS: These results point to a possible causative relationship between TS and opioid analgesia.

Opioids for neuropathic pain.

BACKGROUND: This is an updated version of the original Cochrane review published in Issue 3, 2006, which included 23 trials. The use of opioids for neuropathic pain remains controversial. Studies have been small, have yielded equivocal results, and have not established the long-term profile of benefits and risks for people with neuropathic pain. OBJECTIVES: To reassess the efficacy and safety of opioid agonists for the treatment of neuropathic pain. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (to 24th October 2012), MEDLINE (1966 to 24th October 2012 ), and EMBASE (1980 to 24th October 2012) for articles in any language, and reference lists of reviews and retrieved articles. SELECTION CRITERIA: We included randomized controlled trials (RCTs) in which opioid agonists were given to treat central or peripheral neuropathic pain of any etiology. Pain was assessed using validated instruments, and adverse events were reported. We excluded studies in which drugs other than opioid agonists were combined with opioids or opioids were administered epidurally or intrathecally. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and included demographic variables, diagnoses, interventions, efficacy, and adverse effects. MAIN RESULTS: Thirty-one trials met our inclusion criteria, studying 10 different opioids: 23 studies from the original 2006 review and eight additional studies from this updated review.Seventeen studies (392 participants with neuropathic pain, average 22 participants per study) provided efficacy data for acute exposure to opioids over less than 24 hours. Sixteen reported pain outcomes, with contradictory results; 8/16 reported less pain with opioids than placebo, 2/16 reported that some but not all participants benefited, 5/16 reported no difference, and 1/16 reported equivocal results. Six studies with about 170 participants indicated that mean pain scores with opioid were about 15/100 points less than placebo.Fourteen studies (845 participants, average 60 participants per study) were of intermediate duration lasting 12 weeks or less; most studies lasted less than six weeks. Most studies used imputation methods for participant withdrawal known to be associated with considerable bias; none used a method known not to be associated with bias. The evidence, therefore, derives from studies predominantly with features likely to overestimate treatment effects, i.e. small size, short duration, and potentially inadequate handling of dropouts. All demonstrated opioid efficacy for spontaneous neuropathic pain. Meta-analysis demonstrated at least 33% pain relief in 57% of participants receiving an opioid versus 34% of those receiving placebo. The overall point estimate of risk difference was 0.25 (95% confidence interval (CI) 0.13 to 0.37, P < 0.0001), translating to a number needed to treat for an additional beneficial outcome (NNTB) of 4.0 (95% CI 2.7 to 7.7). When the number of participants achieving at least 50% pain relief was analyzed, the overall point estimate of risk difference between opioids (47%) and placebo (30%) was 0.17 (95% CI 0.02 to 0.33, P = 0.03), translating to an NNTB of 5.9 (3.0 to 50.0). In the updated review, opioids did not demonstrate improvement in many aspects of emotional or physical functioning, as measured by various validated questionnaires. Constipation was the most common adverse event (34% opioid versus 9% placebo: number needed to treat for an additional harmful outcome (NNTH) 4.0; 95% CI 3.0 to 5.6), followed by drowsiness (29% opioid versus 14% placebo: NNTH 7.1; 95% CI 4.0 to 33.3), nausea (27% opioid versus 9% placebo: NNTH 6.3; 95% CI 4.0 to 12.5), dizziness (22% opioid versus 8% placebo: NNTH 7.1; 95% CI 5.6 to 10.0), and vomiting (12% opioid versus 4% placebo: NNTH 12.5; 95% CI 6.7 to 100.0). More participants withdrew from opioid treatment due to adverse events (13%) than from placebo (4%) (NNTH 12.5; 95% CI 8.3 to 25.0). Conversely, more participants receiving placebo withdrew due to lack of efficacy (12%) versus (2%) receiving opioids (NNTH -11.1; 95% CI -20.0 to -8.3). AUTHORS' CONCLUSIONS: Since the last version of this review, new studies were found providing additional information. Data were reanalyzed but the results did not alter any of our previously published conclusions. Short-term studies provide only equivocal evidence regarding the efficacy of opioids in reducing the intensity of neuropathic pain. Intermediate-term studies demonstrated significant efficacy of opioids over placebo, but these results are likely to be subject to significant bias because of small size, short duration, and potentially inadequate handling of dropouts. Analgesic efficacy of opioids in chronic neuropathic pain is subject to considerable uncertainty.  Reported adverse events of opioids were common but not life-threatening. Further randomized controlled trials are needed to establish unbiased estimates of long-term efficacy, safety (including addiction potential), and effects on quality of life.

Oxycodone alters temporal summation but not conditioned pain modulation: preclinical findings and possible relations to mechanisms of opioid analgesia.

Opioid analgesia is mediated primarily by modulating (inhibiting and enhancing) pain mechanisms at the spinal and supraspinal levels. Advanced psychophysical paradigms of temporal summation (TS) and conditioned pain modulation (CPM) likely represent pain mechanisms at both levels. Therefore, the study of opioid effects on TS and CPM can shed light on their analgesic mechanisms in humans. The current randomized, double-blind study tested the effects of oxycodone on the magnitude of both TS and CPM in 40 healthy subjects. TS was tested by measuring increments in pain intensity in response to 10 repetitive painful phasic heat stimuli. CPM was assessed by subtracting the response to a painful phasic heat stimulus administrated simultaneously with a conditioning cold pain stimulus from a painful phasic heat stimulus alone. These paradigms were tested before and at 60, 120, and 180 minutes after administration of a single oral dose of either oxycodone or an active placebo. Repeated-measures analysis of variance revealed significant effects of oxycodone, but not placebo, on the magnitude of TS (F=7.196, P<.001). Pairwise comparisons revealed that relative to baseline, TS was significantly reduced at 60 minutes (P=.008) and at 180 minutes (P=.017) after oxycodone administration. In contrast, no significant effects of either oxycodone (F=0.871, P=.458) or placebo (F=2.086, P=.106) on the magnitude of CPM were found. These results suggest that under the current experimental conditions, oxycodone exerted spinal, rather than supraspinal, analgesic effects. Furthermore, compared with CPM, TS seems more suitable for studying the mechanisms of opioid analgesia in humans.

Predicting the analgesic effect to oxycodone by 'static' and 'dynamic' quantitative sensory testing in healthy subjects.

The large inter-individual variability in the magnitude of analgesia in response to opioids and the high prevalence of adverse events associated with their use underline the clinical importance of being able to predict who will or will not respond to opioid treatment. The present study used both static and dynamic quantitative sensory testing (QST) on 40 healthy volunteers in order to test whether this methodology can predict the analgesic effects of oral oxycodone, as compared to a placebo, on latency to onset, pain intensity, and tolerance to the cold pressor test (CPT). Static QST consisted of measuring heat and cold pain thresholds. Dynamic QST included measurements of the magnitude of the diffuse noxious inhibitory control (DNIC)-like effect and of temporal summation (TS). Results showed that oxycodone, but not the placebo, significantly elevated the latency and tolerance to cold pain and significantly reduced pain intensity. The static QST results showed that heat pain thresholds predicted the magnitude of reduction in pain intensity in response to oxycodone treatment (F((1,22))=5.63, p=0.027, R(2)=0.17). The dynamic QST results showed that TS predicted the effect of oxycodone on the tolerance to CPT (F((1,38))=9.11, p=0.005, R(2)=0.17). These results suggest that both static and dynamic QST have the potential to be useful in the prediction of the response to opioid treatment.