[Dibucaine for spinal anesthesia is a probable risk for cauda equina syndrome]

A 64-year-old man was scheduled for transure thral resection of the prostate. The patient's medical history showed borderline diabetic state and two uncomplicated surgeries under spinal anesthesia. Spinal anesthesia was performed at the L 3/4 interspace using hyperbaric 0.24% dibucaine 2.2 ml, which was followed by general anesthesia because the anesthesia level had spread only to the lower left side of the body. On the next day, he complained of difficulty of defecation and urination combined with hypesthesia around the anus, which was diagnosed as cauda equina syndrome. The symptoms had not changed for three weeks. Then, there was a gradual recovery but slight hypesthesia remained even four months after the surgery. Speculation of this clinical etiology suggests that high concentration of dibucaine, having maldistributed inside the intrathecal space, affected cauda equina, which resulted in irreversible nerve damage. There were other risk factors for cauda equina syndrome in this patient such as lithotomy position, history of frequent spinal anesthesia, diabetes and advanced age. None of these are contraindication for spinal anesthesia. Many elderly patients particularly undergoing urological surgeries are likely to have such risk factors. Therefore at least dibucaine should be avoided for spinal anesthesia because of its high neurotoxicity compared with other local anesthetics.