David Niv

Burning Mouth Syndrome: Will Better Understanding Yield Better Management?

Abstract:u2003 “Burning mouth syndrome” (BMS) refers to a chronic orofacial pain disorder usually unaccompanied by mucosal lesions or other clinical signs of organic disease. BMS is typically characterized by a continuous, spontaneous, and often intense burning sensation as if the mouth or tongue were scalded or on fire.

Causes of pain in degenerative bone and joint disease: a lesson from vertebroplasty

Pain in degenerative bone and joint disease is usually attributed to sensitized nociceptors in inflamed periarticular soft tissues. Here we draw attention to the potential contribution of intrinsic bone innervation. The structure and innervation of articular bone ends is analogous to that of teeth. Although some dental pain derives from inflamed periodontal soft tissue, a more important source is the dentine and root canal. By analogy, pain on weight bearing in osteoarthritis and related conditions may be due to compressive forces applied to the innervation of subchondral bone exposed by erosion of the overlying cartilage. Pain relief obtained by injecting acrylic cement into the bone interior during percutaneous vertebroplasty is consistent with this concept. The development of a new family of pain relief options based on marrow canal treatment may be a realistic possibility.

Dextromethorphan attenuation of postoperative pain and primary and secondary thermal hyperalgesia

Purpose: To determine the effect of 90 mg dextromethorphan (DM)po vs placebo 90 min preoperatively, on the immediate and delayed postoperative course.Methods: Thirty patients undergoing laparoscopic cholecystectomy or inguinal hernioplasty under general anesthesia were studied. Half (DM) received 90 mg dextromethorphan and half received placebo 90 min before anesthesia. Intravenous Patient Controlled Aanalgesia with morphine was available for two hours within a six-hour observation period; 75 mg diclofenacim prn was given later in PACU and on-ward (24 hr). Pain was assessed using the visual analogue scales. Thermal thresholds for cold and hot sensation and for pain (by limit method) were evaluated at the site of skin incision (primary-) and distantly (secondary hyperalgesia). Von Frey filaments were applied testing touch sensation. Sedation level and morphine consumption were also assessed in PACU.Results: Demographic, surgical and perioperative parameters were similar; no untoward effects were encountered. Pain intensity and sedation were lower, and the feeling of well-being was greater, in the DM patients: onevs five (median), twovs five, fivevs two, respectively,P<0.01 (90 min time-point). Thermal application revealed absence of primary and secondary hyperalgesia only in the DM patients; von Frey filaments induced similar pain sensation in both groups. Mean morphine/group, morphine/weight and diclofenac injection rates were ∼55% lower in the DM group: 2.1±1.2 (SD)vs 4.7±2.3, 0.03±0.02vs 0.07±0.03, 1.0±0.3vs 2.4±0.2, respectively,P<0.01.Conclusions: Compared with placebo, DM enabled reduction of postoperative analgesics consumption, improved well-being, and reduced sedation, pain intensity and primary and secondary thermal hyperalgesia.RésuméObjectif: Déterminer l’effet de 90 mg de dextrométhorphane (DM)po vs un placebo, administrés 90 min avant l’opération, sur l’évolution postopératoire immédiate et tardive.Méthode: L’étude a porté sur 30 patients devant subir une cholécystectomie laparoscopique ou un hernioplastie inguinale. La moitié a reçu 90 mg de dextrométhorphane et l’autre moitié, un placebo, 90 min avant le début de l’anesthésie générale. La morphine, en qualité d’analgésie intraveineuse autocontrôlée, a été disponible pendant deux heures sur une période d’observation de six heures; 75 mg de diclofénacim prn ont été administrés plus tard à la salle de réveil et à la chambre (24 h). La douleur a été évalué grâce à l’échelle visuelle analogique. Les seuils thermiques de sensation au froid et à la chaleur ainsi qu’à la douleur (selon une méthode du seuil différentiel) ont été évalués au site de l’incision cutanée (hyperalgésie primaire) et à distance (hyperalgésie secondaire). Des filaments von Frey ont été appliqués pour tester le toucher. On a aussi évalué, à la salle de réveil, le niveau de sédation et la consommation de morphine.Résultats: Les paramètres démographiques, chirurgicaux et périopératoires ont été similaires: aucun effet indésirable n’a été noté. L’intensité de la douleur et de la sédation a été plus faible, et le confort meilleur, chez les patients du groupe DM: unvs cinq (médiane), deuxvs cinq, cinqvs deux, respectivement,P<0,01 (90 min après le début de l’analgésie). L’épreuve de sensibilité thermique a révélé l’absence d’hyperalgésie primaire et secondaire chez les patients du groupe DM seulement; les filaments von Frey ont induit une sensation de douleur similaire chez les patients des deux groupes. La consommation moyenne de morphine selon le groupe et selon le poids des patients ainsi que les taux d’injection de diclofénac ont été de ∼55% plus bas dans le groupe DM: 2,1±1,2 (écart type)vs 4,7±2,3; 0,03±0,02vs 0,07±0,03; 1,0±0,3vs 2,4±0,2, respectivement,P<0,01.Conclusion: Comparé à un placebo, le DM a permis de réduire la consommation d’analgésiques postopératoires, a amélioré le confort et a réduit la sédation, l’intensité de la douleur et l’hyperalgésie thermique primaire et secondaire.

Postherpetic Neuralgia: The Never‐Ending Challenge

Abstract:u2003 Postherpetic neuralgia (PHN) is defined as pain that persists 1 to 3u2003months following the rash of herpes zoster (HZ). PHN affects about 50% of patients over 60u2003years of age and 15% of all HZ patients. Patients with PHN may experience two types of pain: a steady, aching, boring pain and a paroxysmal lancinating pain, usually exacerbated by contact with the involved skin.

Position paper of the European Federation of IASP Chapters (EFIC) on the subject of pain management

Among the complaints that bring patients to see their physician, pain in its various manifestations is the most frequent. In spite of this, pain is often not adequately addressed or managed. The aim of this position paper is to present the viewpoint and recommendations of EFIC on the subject of pain management. Our overall objective is to encourage adoption by architects of healthcare systems in Europe and worldwide of a set of specific recommendations. Every patient is entitled to the implementation of these recommendations in a professional, accessible and timely manner.

The assessment of radiating low back pain by thermal sensory testing

Low back pain radiating into the legs is a common pain syndrome. However, neurological examination, imaging and electromyographic studies are of limited value for prognosis or therapy. The origin of the pain remains unknown. The aim was to evaluate the potential of thermal sensory testing to serve as a diagnostic tool in 24 patients who had low back pain radiating down the S1 dermatome, compared with 26 pain‐free controls. The method of limits was used to detect the thresholds of warm sensation, cold sensation, warm pain and cold pain at the L4, L5 and S1 dermatomes of the symptomatic and the non‐symptomatic legs. Thresholds on the asymptomatic leg were similar to values obtained in controls. We found a significantly higher threshold for cold sensation in the S1 dermatome of the symptomatic leg of the patients compared with the controls (p< 0.005). In addition, patients who had abnormal neurological examination (50%) had higher thresholds for cold sensation or cold pain in the three dermatomes tested at the symptomatic leg compared with the non‐symptomatic leg. No differences in the thresholds of warm sensation or warm pain were detected. We propose that these findings indicate selective damage to the Aδ fibres which are involved in transmission of cold sensation and pain, presumably by root compression. We found no evidence of involvement of C fibres, which transmit warm sensation and pain. Thermal testing should be considered among the testing modalities that are capable of demonstrating objective findings in patients with radiating low back pain.

Mesenteric artery clamping/unclamping-induced acute lung injury is attenuated by N-methyl-D-aspartate antagonist dextromethorphan.

Lung N-methyl-D-aspartate receptors (NMDAR) may cause excitotoxic pulmonary edema if activated. Acute lung injury may be mediated by oxidative stress, frequently generated by local or remote ischemia and reperfusion (IR). This experimental study assessed the effects of intravenous dextromethorphan, an NMDAR antagonist, on reperfusion lung injury following superior mesenteric artery (SMA) clamping/unclamping. SMA of 48 (12 per group) anesthetized adult male Wistar rats was clamped for 90 min (IR); 48 additional rats underwent a sham laparotomy (control). The experimental timeframe was identical in all groups. Ten minutes before unclamping, three dextromethorphan doses were administered intravenously in three IR and three control groups, followed by 3 h of respiratory and hemodynamic assessment and postexperimental assessment of survival. Intravenous 10 and 20 mg/kg dextromethorphan attenuated an 85% increase in peak ventilatory pressure, a 45% reduction in PO2/FiO2, 4–12-fold increase in bronchoalveolar lavage-retrieved volume, and polymorphonuclear leukocytes/bronchoalveolar cells ratio, all associated with SMA unclamping in the IR-nontreated and the IR-40 mg/kg dextromethorphan-treated rats. Lung tissue polymorphonuclear leukocyte count, total xanthine oxidase activity, reduced glutathione, and wet-to-dry weight ratio were all within normal ranges in the two lower-dose-treated groups. These effective regimens were also associated with longer postexperimental animal survival. Dextromethorphan was not associated with changes in three control groups. Thus, Intravenous dextromethorphan mitigates lung reperfusion injury following SMA clamping/unclamping in a dose-dependent manner. This is a novel potential use of dextromethorphan in vivo.

Late antinociception and lower untoward effects of concomitant intrathecal morphine and intravenous buprenorphine in humans

STUDY OBJECTIVEnTo evaluate the perioperative antinociceptive effect of intrathecal morphine (a pure mu agonist), intravenous (IV) buprenorphine (a partial mu agonist) or their combination.nnnDESIGNnRandomized, double-blind, placebo-controlled study.nnnSETTINGSnAnesthesiology department of a university-affiliated public hospital.nnnPATIENTSn45 ASA physical status I, II, and III patients undergoing hysterectomy with general anesthesia.nnnINTERVENTIONSnPreoperative and postoperative regimens consisted of intrathecal morphine 4.3 microg.kg(-1) plus IV 0.9% saline (Group 1), IV buprenorphine 1.3 microg.kg(-1) plus intrathecal saline (Group 2), and intrathecal morphine 4.3 microg.kg(-1) plus IV buprenorphine 1.3 microg.kg(-1) (Group 3; postoperative supplements consisting of IV buprenorphine 1.3 microg.kg(-1) plus intrathecal saline).nnnMEASUREMENTS AND MAIN RESULTSnGroup 2 and 3 patients were given three analgesic dosings compared with two dosings in Group 1 (p < 0.001). The duration of action in Group 2 was significantly shorter (p = 0.001) than in the other two groups. The 12-hour postoperative pain intensity and sedation in Group 3 was significantly lower (p < 0.05) than in the other groups. Side effects (mainly pruritus and nausea and vomiting) were significantly fewer (p < 0.05) in Groups 2 and 3 (26% and 28%, respectively) than in Group 1 (46%).nnnCONCLUSIONSnThe concomitant administration of intrathecal morphine and IV buprenorphine alleviates pain sensation and minimizes sedation more effectively than when given after the administration of either drug separately. In addition, IV buprenorphine affords a reduction in side effects.

Effect of Second-Stage 0.25% Epidural Bupivacaine on the Outcome of Labor

OBJECTIVEnTo evaluate the effect of second-stage epidural bupivacaine on the outcome of labor.nnnMETHODSnTwo groups of 35 patients each were randomly allocated to receive continuous epidural bupivacaine throughout labor (group 1) or until an 8-cm dilatation of the cervix (group 2).nnnRESULTSnThere was no significant difference between the 2 groups in the rates of instrument deliveries and in their Apgar scores.nnnCONCLUSIONSnThe administration of continuous epidural bupivacaine (0.25%) throughout labor and delivery does not seem to affect the outcome of labor.

Exploration of the Evidence

Abstract:u2003 Faced with rapidly escalating costs, healthcare policy makers are increasingly turning to research evidence to serve as a basis for their population‐based decisions on access and funding of new and existing therapies—health technology assessment. A two‐stage approach is often used to arrive at a policy recommendation for a given treatment. First, following a systematic review of literature, the “level of evidence” for the treatment is assessed according to epidemiological principles. Then a grade of policy recommendation is provided based on both the level of evidence and the applicability of the evidence to current clinical practice. To assess the current evidence basis for refractory neuropathic pain, a comprehensive search was undertaken for systematic reviews of pharmacological interventions and interventional procedures (ie, spinal cord stimulation, therapeutic blocks, radiofrequency procedures, and surgery). Of the 33 systematic reviews identified, the majority provided evidence for the use of drugs and spinal cord stimulation in the management of various neuropathic pain indications. Little evidence was found for either radiofrequency procedures or therapeutic blocks. By including randomized controlled trials, a number of these systematic reviews indicate a high grade of evidence. Nevertheless, more pragmatic clinical trials are needed to address the evidence needs of healthcare policy makers. These trials should address a direct comparison of the relative effectiveness of neuropathic pain therapies, particularly in combination with other therapies and at different points in the disease course.