The iatrogenically produced drug injection injury of a peripheral nerve is of particular concern, because of its clinical and medicolegal implications.
With the numerous agents administered by intramuscular injection, this injection injury has come to be recongnized as a not infrequent cause of pain, disability, and especially in childern, the permanent, severe paralytic disorders.
The author selected gentamicin sulfate as an agent of injection injury among numerous antibiotics, which is one of the most commonly used antibiotics in the clinical fields, to find out the neurotoxic effect of this antibiotics to the peripheral nerve. Gentamicin sulfate solution was injected into rat sciatic nerve intrafascicularly with 30-gauge needle. The injected portion was resected segmentally and observed periodically under the light and electron microscope.
The followings are the result
1. Intraneural connective tissue were degenerated by gentamicin injection. It was peak at two weeks, but was recovered from three weeks.
2. The changes of myelin sheath, distortion and shrinkage, were started just after injection and was peak at two weeks specimen. However, it was normalized completely at eight weeks.
3. Some vacuoles and amorphous substances in the axoplasm and macrophage in the connective tissues observed in two weeks.
4. From above results, intrafascicular injection of gentamicin produces severe nerve injury, within two weeks. But these changes were reversible after two weeks experimentally.
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