[Nerve biopsy in the diagnosis of peripheral neuropathies]

The indications for nerve biopsy have diminished in recent years. This examination nevertheless remains essential in certain cases of peripheral neuropathies, making it possible to specify the diagnosis or the mechanism of injury for a therapeutic purpose. It is a simple but "invasive" procedure, which can only be performed once on the same nerve. The indications are thus discussed on a case-by-case basis and based on a range of clinical, electrophysiological, biological or even genetic arguments. This involves close collaboration between clinical physicians and pathologists. The main difficulty of this biopsy concerns the fragility of the sample and the techniques necessary for its interpretation, requiring it to be carried out in expert centers. Nerve biopsy is closely related to skin biopsy in the search for small fiber neuropathy. It is a particular technique, but very well codified. The purpose of this review is to recall the indications and contraindications of nerve biopsy, and to explain what the contributions are but also the limits of this examination as well as of skin biopsy.