Thorsten Giesecke

Quantitative sensory testing in vulvodynia patients and increased peripheral pressure pain sensitivity.

OBJECTIVE: To assess both regional (vulvar) and overall (generalized) pain sensitivity in women with vulvodynia to determine whether both are increased, suggestive of altered central pain processing. METHODS: Seventeen patients (aged 18–60 years) with vulvodynia and 23 age-matched control subjects were included in this cross-sectional study. Pressure pain thresholds in the vulvar area were evaluated in 23 defined locations using a newly developed vulvodolorimeter. Peripheral pressure pain sensitivity was assessed by applying 1) continuously ascending pressures to 3 bilateral locations (thumb, deltoid, and shin), and 2) discrete pressure stimuli to the thumb using both an ascending and random sequence of varying pressures. RESULTS: Pain thresholds at all vulvar locations were lower in the women with vulvodynia than in pain-free control subjects. Similarly, peripheral pain thresholds were lower at the thumb in women with vulvodynia when obtained by discrete ascending or random staircase paradigms, as well as at the thumb, deltoid, and shin when tested by dolorimeter (P < .05). Findings were similar in both those with generalized vulvar dysesthesia and those with localized vestibulodynia. The quantitative results obtained with the vulvodolorimeter and with the more subjective cotton-tipped swab testing routinely used in diagnosis were strongly correlated. CONCLUSION: Women with vulvodynia displayed significantly increased pressure pain sensitivity in both the vulvar region and in peripheral body regions, suggesting a “central” component to the mechanisms mediating this disorder. Both the novel vulvodolorimeter and the thumb pressure stimulator may assist in future experimental tests of this and related hypotheses. LEVEL OF EVIDENCE: II-2

The association between experimental and clinical pain measures among persons with fibromyalgia and chronic fatigue syndrome

Evoked or experimental pain is often used as a model for the study of clinical pain, yet there are little data regarding the relationship between the two. In addition, there are few data regarding the types of stimuli and stimulus intensities that are most closely related to clinical pain.

A comparison between IV paracetamol and IV metamizol for postoperative analgesia after retinal surgery

ABSTRACT Objective: To assess clinical efficacy of IV paracetamol 1 g and IV metamizol 1 g on a 24‐h dosing schedule in this randomized, double-blinded, placebo-controlled study of 38 ASA physical status I–III patients undergoing retinal surgery. Research design and methods: General anaesthesia using remifentanil, propofol, and desflurane was performed for surgery. The patients were randomly allocated to three groups, receiving infusions of paracetamol 1 g/100 mL (Para Group), of metamizol 1 g/100 mL (Meta Group), or of 100 mL of saline solution as placebo control (Plac Group) 30 min before arrival in the recovery area and every 6 h up to 24 h postoperatively. All patients had unrestricted access to intravenous opioid rescue medication. Main outcome measures: The primary efficacy variables were pain scores at rest over 30 h postoperatively analysed by using repeated ANOVA measurement. Secondary efficacy variables were pain scores on coughing, also analysed by repeated ANOVA measurement. Results: Five patients in the Plac Group and one patient in the Meta Group interrupted the study protocol. Regarding pain scores at rest, Mauchly-test of sphericity was significant ( p = 0.03). For the time effects a significant result was detected ( p < 0.001). The main effect between the three treatment groups was significantly different ( p = 0.01). The Bonferroni adjusted pair wise comparisons between the Plac Group and the Para Group showed a significant difference in favour of IV paracetamol ( p = 0.024; mean difference 14.8; 95% CI 1.6–28.0), between the Plac Group and the Meta Group in favour of IV metamizol ( p = 0.025; mean difference 14.4; 95% CI 1.5–27.4), and no significant difference between the Para Group and the Meta Group ( p = 1.0; mean difference 0.4; 95% CI –12.8 to 13.6). Pain scores on coughing showed a significant different main effect between the three treatment groups ( p = 0.022). The Bonferroni adjusted pair wise comparisons between the Plac Group and the Para Group showed a significant difference in favour of IV paracetamol ( p = 0.032; mean difference 17.9; 95% CI 1.3–34.6), a difference, though not reaching statistical significance, in favour of IV metamizol between the Plac Group and the Meta Group ( p = 0.081; mean difference 15.0; 95% CI –1.4 to 31.4), and no significant difference between the Para Group and the Meta Group ( p = 1.0; mean difference 2.9; 95% CI –13.8 6 to 19.6). None of the patients experienced itching; one patient in the Meta Group developed a mild erythema. There was no statistical difference in the incidence of nausea (Plac vs. Para Group: p = 0.94, Plac vs. Meta Group: p = 0.98, Para vs Meta Group: p = 0.95) or vomiting (Plac vs. Para Group: p = 0.73, Plac vs. Meta Group: p = 0.85, Para vs Meta Group: p = 0.86) between the groups. Patients in the Plac Group experienced significantly more often sedation than patients in the Meta Group ( p = 0.049). There was a trend of higher sedation in the Plac Group than in the Para Group, which did not reach statistical significance ( p = 0.07). There was no difference in sedation between the Meta and the Para Groups ( p = 0.84). Conclusion: IV paracetamol 1 g has a similar analgesic potency as IV metamizol 1 g for postoperative analgesia after retinal surgery.