G57.9Unspecified mononeuropathy of lower limb

G57.9 is the ICD-10-CM diagnosis code for unspecified mononeuropathy of lower limb. It belongs to category G57 (mononeuropathies of lower limb), block G50-G59 (nerve, nerve root and plexus disorders) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

Within G57, choose G57.9 (Unspecified mononeuropathy of lower limb) only when documentation doesn't support a more specific option: lesion of sciatic nerve (G57.0), Meralgia paresthetica (G57.1), lesion of femoral nerve (G57.2), lesion of lateral popliteal nerve (G57.3), lesion of medial popliteal nerve (G57.4), tarsal tunnel syndrome (G57.5), lesion of plantar nerve (G57.6), Causalgia of lower limb (G57.7) and 1 more.

To report this condition, pick the subcode that matches the documentation: G57.90 (limb), G57.91 (limb), G57.92 (limb) and G57.93 (limbs).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.