title: Posterior interosseous nerve discontinuity due to compression by lipoma: report of 2 cases.
abstract: Paralysis of the posterior interosseous nerve (PIN) secondary to compression is a rare clinical condition. Entrapment neuropathy may occur at fibrous bands at the proximal, middle, or distal edge of the supinator. Tumors are a relatively rare but well-known potential cause. The authors present 2 cases of PIN lesions in which compression by a benign lipoma at the level of the elbow resulted in near transection (discontinuity) of the nerve. They hypothesize a mechanism-a "sandwich effect"-by which compression was produced from below by the mass and from above by a fibrous band in the supinator muscle (i.e., the leading edge of the proximal supinator muscle [arcade of Fröhse] in one patient and the distal edge of the supinator muscle in the other). A Grade V Sunderland nerve lesion resulted from the advanced, chronic compression. The authors are unaware of a similar case with such an advanced pathoanatomical finding.
authors.affiliation: Departments of Neurologic Surgery and Radiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Andrés A
authors.initials: AA
authors.lastname: Maldonado
authors.affiliation: Departments of Neurologic Surgery and Radiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Howe
authors.affiliation: Departments of Neurologic Surgery and Radiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
mesh_terms: D000368:Aged; D004550:Elbow; D005260:Female; D006801:Humans; D008067:Lipoma / Q000150:complications* / Q000175:diagnosis / Q000601:surgery*; D008297:Male; D009408:Nerve Compression Syndromes / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery*
keywords: PIN = posterior interosseous nerve; arcade of Fröhse; compression; palsy; paralysis; peripheral nerve; posterior interosseous nerve; radial nerve; supinator