Irritancy after Intrathecal Spinal Injection

Transient neurological symptoms have been observed in patients after spinal anesthesia (Hampl et al. 1995). Activity and tolerability of new local anesthetics after intrathecal injection were studied in various animal species in order to predict both parameters for spinal (subarachnoid) anesthesia in patients. 

For detailed description of the pharmacological effects see the respective Chapter in Drug Discovery and Evaluation - Pharmacological Assays . 

Kirihara et al. (2003) compared neurotoxicity of intrathecal and epidural lidocaine in rats. 

Kirihara et al. (2003) compared neurotoxicity of intrathecal and epidural lidocaine in rats. Male Sprague-Dawley rats were anesthetized with sodium pentobarbital (30 mg/kg i.p.) and 1.5% halothane. A catheter of stretched polyethylene tubing PE-10 was introduced into the subarachnoid or epidural space using an aseptic technique. Catheters were passed through the L4-L5 intervertebral space and advanced 1.3 cm in the caudal direction. Rats were allowed 4 days to rest for recovery from the operation. 

To measure the response to noxious heat stimulus, a tail flick test was performed. A100-W projector lamp was focused on the distal segment of the tail approximately 5 cm from the tip. The time at which rats withdrew the tail was defined as the tail flick latency. A cutoff time of 10 sec was used to avoid damage of the tail. 

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