To the Editor
I read with interest Dr. deJong’s article concerning spinal Lidocaine.
In 25 years of practice, I’ve had one patient who had a partial cauda equina syndrome in which 2% Lidocaine was injected (total 2cc at most) during a wet tap with an attempted epidural. The residual is a partially emptying bladder and some numbness in the perineal area, but the patient has full sexual function (male).
As I read Dr. deJong’s concerns about the effect of Lidocaine molecules on the spinal cord and nerve roots, I found myself continuing to ask, “Why don’t we see this more often with epidural anesthesia? Surely the molecules of lidocaine that diffuse through the aura and coverings of the dorsal nerve roots do not undergo a detoxification process while transiting from the epidural space to the subarachnoid structures?”
Do you or anyone have an answer to this question? Surely we achieve a CSF concentration of Lidocaine using epidurals that must approximate that achieved with 2% subarachnoid Lidocaine? Have I missed something here, o should we all be considering abandoning Lidocaine for epidurals as well?
I would welcome responses from Dr. deJong and other Newsletter readers.
Clair S. Weenig, M.D. Assistant Clinical Professor Department of Anesthesia University of California Medical Center, San Francisco, CA