title: [Compression of the peroneal nerve by a synovial cyst in a 7-year-old child].
abstract: OBJECTIVE
  Compressions of the peroneal nerve by synovial cysts are rare. Sixty cases have been described since 1921.
  
  
  METHODS
  It concerns extrinsic compression of the peroneal nerve by a synovial cyst, developed from the upper tibiofibular joint, in a seven years old child. As far as we know, this is the youngest age found in the relevant literature. Because of a swiftly appearing painful swelling, along with complete paralysis of the peroneal nerve, an electromyogram and a magnetic resonance imaging were performed, in view to confirm the diagnosis and to clarify cyst topography.
  
  
  RESULTS
  Removal of the cyst led to healing with complete recovery of the peroneal nerve within three months.
  
  
  CONCLUSIONS
  Both intraneural and extraneural cysts exist. Most authors agree that their source is the upper tibiofibular joint. In case of intraneural cysts, complete removal is sometimes impossible. It seems preferable to make a longitudinal incision in the nerve to lay the tumor flat. Indeed, everything possible should be done to find, then ligature, the pedicle which passes by the articular nerve ending of the peroneal nerve in order to avoid recurrence. Extraneural cysts are sometimes intra- or inter-muscular and create a swelling which is often palpable. It is necessary to remove the cyst carefully and to dissociate it from the nerve endings.
  
  
  CONCLUSIONS
  In all cases, recurrence is not infrequent. Longer the delay before intervention is less satisfactory the recovery will be.
authors.affiliation: Service d'Orthopédie-Traumatologie adulte et infantile, Hôpital Jean Bernard, C.H.U. de la Milétrie, Poitiers.
authors.forename: L E
authors.initials: LE
authors.lastname: Gayet
authors.forename: F
authors.initials: F
authors.lastname: Morand
authors.forename: J M
authors.initials: JM
authors.lastname: Goujon
authors.forename: P
authors.initials: P
authors.lastname: Pries
authors.forename: J P
authors.initials: JP
authors.lastname: Clarac
mesh_terms: D002648:Child; D004576:Electromyography; D006801:Humans; D007719:Knee Joint; D008279:Magnetic Resonance Imaging; D008297:Male; D009408:Nerve Compression Syndromes / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D010543:Peroneal Nerve; D013581:Synovial Cyst / Q000150:complications* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
vernacular_title: Compression du nerf sciatique poplité externe par un kyste synovial chez un enfant de 7 ans.