- Question
- Can nerve injuries be graded more finely according to which connective tissue layers are disrupted?
- Design
- Anatomical and clinical classification paper building on Seddon's scheme.
- Patients
- Peripheral nerve injuries causing loss of function.
- Intervention
- Five-degree grading based on axon, endoneurium, perineurium and epineurium integrity
- Comparison
- Seddon's three-type classification
- Primary outcome
- Expected recovery potential for each degree of injury
- Key result
- First degree equates to neurapraxia and fifth degree to complete transection; second to fourth degrees subdivide axonotmesis by progressive loss of endoneurial and perineurial continuity, with prognosis worsening as more layers are lost and fourth/fifth degree injuries generally needing surgery.
- Limitations
- The degree of injury is largely inferred retrospectively or at exploration and cannot be reliably assigned clinically early on; later authors added a sixth (mixed) grade.
- Impact on practice
- Widely examined alongside Seddon; helps explain why some 'axonotmesis' lesions fail to recover and need exploration and grafting.