Transient radicular irritation with intrathecal plain lignocaine.

BACKGROUND

The aetiology of the syndrome known as transient radicular irritation (TRI) has generated much interest.

METHOD

A 50-year-old woman had right knee arthroscopy performed under spinal anaesthesia with 1% plain lignocaine.

RESULT

At home, on the night of the procedure, she was woken by severe, bilateral cramp-like pain in both buttocks radiating to her thighs. Neurological examination of her lower limbs, the next morning, was entirely normal. The pain lasted for 36 h and a full recovery was made.

CONCLUSION

This case of transient radicular irritation occurred in a patient given 40 mg of subarachnoid lignocaine (the lowest dose of isobaric preservative-free lignocaine reported thus far that has been associated with these symptoms). Her operation was performed in the supine position. The lack of confounding factors (hyperbaricity, high concentration solution, preservatives, lithotomy position) suggests lignocaine as a possible cause, yet current theories do not fully explain the aetiology of transient radicular irritation. Results from large-scale epidemiological studies will hopefully provide insight into the cause of this problem.