Peripheral nerve injury classification

Classification of peripheral nerve injury assists in prognosis and determination of treatment strategy. Classification of nerve injury was described by Seddon in 1943 and by Sunderland in 1951. The lowest degree of nerve injury in which the nerve remains intact but signaling ability is damaged is called neurapraxia. The second degree in which the axon is damaged but the surrounding connecting tissue remains intact is called axonotmesis. The last degree in which both the axon and connective tissue are damaged is called neurotmesis.

In 1943, Seddon described three basic types of peripheral nerve injury that include:

It is a temporary interruption of conduction without loss of axonal continuity.In neuropraxia, there is a physiologic block of nerve conduction in the affected axons.

Other characteristics:

It involves loss of the relative continuity of the axon and its covering of myelin, but preservation of the connective tissue framework of the nerve ( the encapsulating tissue, the epineurium and perineurium, are preserved ).

Other characteristics:

It is a total severance or disruption of the entire nerve fiber.A peripheral nerve fiber contains an axon (Or long dendrite), myelin sheath (if existence), their schwann cells, and the endoneurium. Neurotmesis may be partial or complete.

Other characteristics:

In 1951, Sunderland expanded Seddon's classification to five degrees of peripheral nerve injury:

Seddon's neurapraxia and first-degree are the same.

Seddon's axonotmesis and second-degree are the same.

Third-degree is included within Seddon's Neurotmesis.

Sunderland's third-degree is a nerve fiber interruption. In third-degree injury, there is a lesion of the endoneurium, but the epineurium and perineurium remain intact. Recovery from a third-degree injury is possible, but surgical intervention may be required.

Fourth-degree is included within Seddon's Neurotmesis.

In fourth-degree injury, only the epineurium remain intact. In this case, surgical repair is required.

Fifth-degree is included within Seddon's Neurotmesis.

Fifth-degree lesion is a complete transection of the nerve. Recovery is not possible without an appropriate surgical treatment.

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