DOES SACRAL POSTERIOR RHIZOTOMY SUPPRESS AUTONOMIC HYPER-REFLEXIA IN PATIENTS WITH SPINAL-CORD INJURY

Objective To study the occurrence of autonomic hyper reflexia (AHR) af ter intradural sacral posterior rhizotomy combined with intradural sac ral anterior root stimulation, performed to manage the neurogenic hype r-reflexic bladder, and to determine the pathophysiological basis of t he uncontrolled hypertensive crisis after sacral de-afferentation. Pat ients and methods Ten patients with spinal cord injury operated using Brindley's method between September 1990 and February 1994 were review ed, Systematic continuous non-invasive recordings of cardiovascular va riables (using a photoplethysmograph) were made during urodynamic reco rdings and the pre-and post-operative vesico-urethral and cardiovascul ar data compared. Results Nine of the 10 patients were examined using a new prototype measurement system; one woman refused the last urodyna mic assessment, Eight of the nine patients who presented with AHR befo re operation still had the condition afterward. There was a marked ele vation in systolic and diastolic blood pressure during the urodynamic examination in all eight patients, despite complete intra-operative de -afferentation of the bladder in five. The elevation of blood pressure started during the stimulation-induced bladder contractions and incre ased during voiding in all cases, Five patients showed a decrease in h eart rate during the increase in blood pressure. However, in three pat ients the heart rate did not change or even sometimes slightly increas ed as the arterial blood pressure exceeded 160 mmHg, when the blood pr essure and heart rate then increased together, Conclusions These resul ts confirm that even after complete sacral de-afferentation, AHR persi sted in patients with spinal cord injury and always occurred during th e stimulation-induced voiding phase. In cases of incomplete de-afferen tation, small uninhibited bladder contractions without voiding occurre d during the filling phase. The blood pressure then increased but neve r reached the value recorded during stimulation-induced micturition, S timulation of afferents that enter the spinal cord by the thoracic and lumbar roots and that are not influenced by sacral rhizotomy could ex plain why AHR increases during urine flow. The distinct threshold of d ecreased heart rate by increasing blood pressure to >160 mmHg focuses attention on the chronotropic influences of the sympathetic nerves in the heart by an exhausted baroreceptor reflex.