Effect of surgical trauma on regional blood flow in rat sciatic nerve

The factors affecting peripheral nerve blood flow (NBF) are not well defined. We used [14C]butanol distribution to quantitate NBF in rat sciatic nerve following either (1) simple surgical exposure (EXP) or (2) EXP plus nerve mobilization and isolation (ISOL). Undisturbed contralateral nerves were controls. The epineurial contribution to NBF after EXP was also assessed. Results (units: ml.min-1 x 100 g-1): Within 1 to 6 h after EXP (N = 7), NBF was 22.1 +/- 2.7 vs 11.9 +/- 1.5 control (P < 0.01). Seven to 24 h after EXP (N = 6), NBF was unchanged from control. Two hours following EXP, both endoneurial NBF and total (epineurial plus endoneurial) NBF were elevated (P < 0.05, P < 0.02, respectively). Within 48 h after ISOL (N = 6) NBF was 30.3 +/- 3.9 vs 13.2 +/- 2.1 control (P < 0.005). Three to seven days after ISOL (N = 8), NBF was unchanged from control.

Surgical trauma induces a brisk flow response in peripheral nerve that is proportionate in duration to the trauma severity. Measurements of NBF after EXP or ISOL are therefore potentially misleading if the changes in NBF due to the trauma are not accounted for.