EFFECTS OF EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY ON REFERRED HYPERALGESIA FROM RENAL URETERAL CALCULOSIS/

In patients suffering from colics due to calculosis of one upper urina ry tract the evolution in time of referred parietal hyperalgesia after stone fragment elimination promoted by extracorporeal shock wave lith otripsy (ESWL) was studied. Before ESWL, all patients presented clinic al evidence(positivity to dermographism and Head's procedure, pinch pa lpation, digital pressure and; Giordano's manoueuver) and instrumental signs (significant lowering of pain threshold to electrical tissue st imulation) of cutaneous, subcutaneous and muscular tissue hyperalgesia in the lumbar region of the affected side. After ESWL, hyperalgesia d ecreased in the three tissues, as shown by progressive change in the c linical tests and an increase in pain threshold to electrical stimulat ion in relation to the extent of stone fragment expulsion. In the ston e-free condition, hyperalgesia had disappeared in the skin but remaine d to a mild and moderate extent in the subcutaneous tissue and muscle respectively. It is concluded that the persistence in time of referred hyperalgesia is only in part linked to the continuing presence and ac tivity of the stone in the urinary tract. To a certain extent, the phe nomenon seems to become independent of the primary focus, possibly as a result of plastic neuronal changes in the central nervous system whi ch, triggered by afferent visceral inputs, are maintained even after t heir removal.