[Peripartum changes of the pelvic ring: usefulness of magnetic resonance imaging]. / Peripartale Veränderungen des Beckenringes: Wie sinnvoll ist die Magnetresonanztomografie?

PURPOSE: Postpartum pelvic pain beyond the normal level poses a problem to obstetricians. Beyond normal physiologic loosening of the pubic symphysis and sacroiliac joints (SIJs) during pregnancy, symphyseal separation and rupture must be excluded. The aim of this prospective study was to determine whether magnetic resonance imaging (MRI) allows for reliable differentiation of normal postpartum findings and pathologic lesions. MATERIAL AND METHODS: The study included a total of 77 women (mean age 30), among them 21 healthy subjects (group A), 21 asymptomatic postpartum women (group B), and 35 patients with postpartum pelvic pain (group C). The analyzed parameters comprised symphyseal and iliosacral tenderness, subjective pain assessed on a visual analog scale, and data pertaining to obstetric history. All 77 women underwent 1.5T MRI of the pelvic ring using oblique angulated coronal T 1-weighted and STIR sequences for imaging of the symphysis and SIJs in one slice package. Analysis of the MR images comprised signal intensities of pelvic bone marrow, width of the symphyseal cleft, and the symphyseal capsule. RESULTS: Subjects in group A in general had a normal bone marrow signal. The STIR sequence showed increased signal intensity of the pubic bone near the symphysis in 16 women (76 %) of group B and 31 patients of group C (86 %) (not significant). An increased periarticular bone marrow signal of the SIJs on the STIR images was seen in 13 women (62 %) of group B and 23 patients (63 %) of group C. The mean width of the symphyseal cleft differed significantly among the three groups (3.4 mm vs. 5.4 mm vs. 6.7 mm). A width >10 mm was observed in only 4 cases (11 %). Moreover, associated findings such as interpubic hematoma (n=23) or tears of the symphyseal capsule (n=7) were detected in patients of group C. CONCLUSION: The wide overlap of findings between symptomatic and asymptomatic postpartum patients does not allow reliable differentiation by MRI of normal and abnormal findings. MRI contributes to the differentiation of symphyseal contusion and rupture and provides information on severe associated changes.

[Respiratory and circulatory parameters as indicators of the postoperative analgesic demand in newborns and infants]. / Atem- und Kreislaufparameter als Indikatoren des postoperativen Analgetikabedarfs bei Neugeborenen und Säuglingen.

AIM OF THE STUDY: Due to immature cognitive functions, infants are unable to communicate their pain perception verbally. To assess postoperative analgesic demand, the anaesthetist has to rely on observational techniques. Generally, pain expression is considered to be a multidimensional phenomenon consisting of physiological, motor-reflex and behavioural patterns. The majority of observational approaches to pain assessment in infants use the behavioural dimension only, regardless of the fact that pain perception might contribute substantially to the stress response. The aim of this study is to evaluate, whether sensitivity and specificity of a behavioural pain scale (CHIPPS [1]) can be improved by adding physiological measures, especially those representing the stress response. PATIENTS AND METHODS: 30 infants aged 0-12 months and scheduled for unilateral herniorrhaphy were studied prospectively. In addition to 9 behavioural items (crying, facial expression, wrinkling of the forehead, motoric restlessness; posture of fingers, arms, legs, toes and torso) the ratio of actual physiological measurements (heart rate, respiratory rate, blood pressure) and their respective preoperative baseline values were recorded by a single observer in 5 minutes intervals during the first hour after recovery from anaesthesia. Maximal efforts were made to achieve valid measures. Factor analysis was performed to determine the dimensionality of the complete item pool. For additional validity testing, receiver operating characteristic curves (ROC) were calculated using the independent opinion of an experienced clinician as an external criterion. Discriminant analysis was performed to assess the accuracy of a combined behavioural and physiological scale. RESULTS: The factor analysis resulted in two independent dimensions: behaviour and cardiocirculatory measurements. The strong intercorrelations of all behavioural items and the fact, that the affective pain experience is expressed by a specific mimic behaviour, suggest the behavioural dimension to be regarded as pain expression. Because of the strictly orthogonal structure of the factor system, the circulatory and the respiratory dimension lack any relationship to pain experience. In addition to these statistical reasons, considerations on practicability disprove blood pressure and respiratory rate as useful pain indicators: Whereas the observer never failed to obtain a behavioural score, only 60% of the blood pressure measures and 80% of the respiratory rates were valid. In contrast, heart rate counts were obtained in over 99% and thus have to be considered as the only practicable physiological measurement in the early postoperative period. Corresponding to the results of the factor analysis, ROC curves suggest that the ability of the heart rate alone to assess pain is not substantially better than a random process, whereas the behavioural scale performs well. In addition the heart rate failed to improve the accuracy of the behavioural scale as shown by the results of a discriminant analysis. CONCLUSIONS: Despite the multidimensional approach and the corresponding multivariate analyses, a unidimensional scale consisting of behavioural items was found to be a valid indicator of an postoperative analgesic demand. Due to the lack of diagnostic properties and difficulties to obtain sound values even under research conditions, physiological measurements like blood pressure, respiratory rate and heart rate are not suitable for the assessment of a postoperative analgesic demand in infants, neither for clinical nor for research purposes.

[Development of an observational scale for assessment of postoperative pain in infants]. / Entwicklung eines Fremdbeobach-tungsbogens zur Beurteilung des postoperativen Schmerzes bei Säuglingen.

In a prospective trial in 139 infants ASA classification I-II 13 observational items were scaled during the first postoperative hour (13 assessments). The items were drawn from the literature and chosen for economic purpose. Factor analyses (Principal component, Kaiser Criterion, Scree-test) were used for the elimination of useless items and for the identification of suitable ones. The discriminative properties of single items and different subsets of items to detect an analgetic demand were tested in discriminant analyses and variance analyses with repeated measurements. Due to insufficient variance four items had to be eliminated: "nasolabial folding", "colour of the face", "sweating of the head", and "muscle tone". The factor analysis if the remaining 9 items resulted in a one factorial solution. Neither the corrected item-scale-correlations nor the inter-item-correlations showed advantageous properties of single items compared with the others. For economic reasons two 5-item scales were chosen for further evaluation in regard to sensitivity, specify and validity. The items "crying", "facial expression", "positioning of the legs", "positioning of the trunc" and "motoric restlessness" built the Children's and Infants Postoperative Pain Scale (CHIPPS) whereas an Infants Postoperative Pain Scale (IPPS) contained the items "crying", "facial expression", "positioning of the arms", "positioning of the trunc" and "motoric restlessness". The latter five items had shown the highest factor loadings. The two systems had a high intern consistency with alpha > 0.90 (p < 0.01) with at least 73% explained variance. Inter-item-correlations and corrected item-scale-correlations showed no differences between the two scales. The discriminant analyses resulted in almost identic data for specify, sensitivity and predictive values of the IPPS compared with the CHIPPS. There was a significant interaction between repeated measurements and the supply of Piritramide and Ketamine, but not of Midazolam. Concurrent and constructive validation were positive for both systems, using administration of Piritramide as a criterion. For clinical purpose the CHIPPS should be preferred, because it has been proven to be valid in children up to 4 years of age and because controlled data on its sensitivity, specify, reliability and validity could already be presented.