Prostaglandin E1 but not corticosteroid increases nerve root blood flow velocity after lumbar diskectomy in surgical patients.

The purpose of this study was to clarify whether prostaglandin E1 (PGE(1)) or corticosteroid could increase blood flow in the nerve root because neurologic symptoms in spinal stenosis may be based on the vascular insufficiency in the nerve root. Fifty-seven patients undergoing lumbar diskectomy were randomly assigned to one of three groups. Each group received one of three protocols for intravenous injection: 10 mL of saline solution, group A (n = 19); 10 mL of PGE(1) (20 microg) solution, group B (n = 19); and 10 mL of dexamethasone (8 mg) solution, group C (n = 19). After lumbar diskectomy, a probe for laser Doppler flowmetry was placed directly on the lumbar nerve root. Nerve root blood flow (RBF) velocity and mean arterial pressure (MAP) were measured before injection (T0), 5 minutes after the start of injection (T1), 10 minutes after the start of injection (T2), and 10 minutes after the end of injection (T3). In groups A and C, these did not change throughout the time course. In group B, MAP decreased significantly at T1 (92%; P <.001), T2 (89%; P <.0001), and T3 (91%; P <.0001), while RBF velocity increased significantly at T1 (125%; P <.05), T2 (128%; P <.05), and T3 (121%; P <.05) compared with T0. The values in group B were different from those in group A (P <.05) and group C (P <.05) at T1 and T2. The results show that intravenous injection of low-dose PGE(1), but not corticosteroid, increases RBF velocity after lumbar diskectomy.