[Chronic pain and regional anesthesia in children]. / Douleurs chroniques et anesthésie locorégionale chez l'enfant.

Chronic pain is usually underestimated in children, due to lack of knowledge and its specific signs. In addition to suffering, chronic pain causes a physical, psychological, emotional, social, and financial burden for the child and his family. Practitioners may find themselves in a situation of failure with depletion of medical resources. Some types of chronic pain are refractory to conventional systemic treatment and may require the use of regional anesthesia. Cancer pain is common in children and its medical management is sometimes insufficient. It is accessible to neuroaxial or peripheral techniques of regional anesthesia if it is limited to an area accessible to one of these techniques and no contraindications (e.g., thrombopenia) are present. Complex regional pain syndrome 1 is not rare in children and adolescents, but it often goes undiagnosed. Regional anesthesia may contribute to the treatment of complex regional pain syndrome 1, mainly in case of recurrence, because it provides rapid effective analgesia and allows rapid implementation of intensive physiotherapy. These techniques have also shown interest in phantom limb pain after limb amputation, but they remain controversial for erythromelalgia pain or chronic abdominopelvic pain. Finally, the treatment of postdural puncture headache due to cerebrospinal fluid leak can be treated by performing an epidural injection of the patient's blood, called a blood-patch. Finally, the management of children with chronic pain should be multidisciplinary (pediatrician, physiotherapist, psychologist, surgeon, anesthesiologist) to support the child and her problem in its entirety.

Characterization of the mechanical behaviour parameters of the costo-vertebral joint.

This in vitro study introduces a new method to determine quantitative parameters characterizing the mechanical behaviour of the costo-vertebral joint. These parameters are useful in building numerical models of the thoracic spine, taking into account the thoracic cage. Nine thoracic cages were isolated from fresh human cadavers. From each cage, three functional units were tested: T1-T2, T5-T6, T9-T10. Loads were applied according to the joint local coordinate system. Every functional unit was tested first intact and again after section of successive costo-transverse ligaments. We used an opto-electronic system to follow the three-dimensional motion of the joint, and obtained non-linear load/displacement curves according to the primary rotation axis. A statistical analysis of these curves allowed the calculation of parameters describing the joint mechanical behaviour: total range of motion, motion in the low-stiffness zone, and flexibilities in the positive and negative quasi-linear zones. These values can be used as a database for mechanical modeling of the spine.