Vibration sense testing with a 128-Hz tuning fork as a tool to determine recovery from epidural neuraxial block

Background and Objectives: Vibration sense testing using a 128-Hz tuning fo rk is a commonly used test in the diagnosis of dorsal horn dysfunction and polyneuropathy. In this open, prospective study, we tested the hypothesis t hat vibration sense testing is a sensitive and specific method to assess re covery from epidural block. Methods: Recovery from epidural block was evaluated in 81 patients undergoi ng cesarean delivery or vein stripping by comparing the use of a 128-Hz tun ing fork with the results of conventional evaluation of block recovery. Con ventional block recovery testing included Bromage-Score, formal muscle powe r testing according to the British Medical Research Council, pinprick testi ng, and warm/cold testing. Epidural blocks were performed by the same anest hesiologist using ropivacaine and sufentanil via an epidural catheter. Afte r obtaining baseline values, an epidural anesthetic was performed and patie nts were tested every 30 minutes until complete recovery from the block was documented with all examined methods. Statistical analysis was performed t o compare the results of the different methods to the time at which baselin e values of vibration sense were reached. Results: At the time vibration sense testing returned to baseline, there wa s no residual motor block according to the Bromage Score in 100% of the pat ients and no residual block for foot flexion and extension. Twelve percent of the patients showed a minimal lack of strength in the quadriceps muscle and 11% had residual sensory anesthesia to pinprick below L5/S1. Conclusions: Based on our observations, recovery of vibration sense corresp onds with recovery of motor block after epidural anesthesia and may serve a s an easy means of documenting recovery with a single test before discharge .