COMPRESSION OF THE PERONEAL NERVE BY A CY ST IN A 7 YEAR-OLD CHILD

Purpose of the study Compressions of the peroneal nerve by synovial cy sts are rare. Sixty cases have been described since 1921. Materials an d methods It concerns extrinsic compression of the peroneal nerve by a synovial cyst, developed from the upper tibiofibular joint, in a seve n years old child. As far as we know, this is the youngest age found i n the relevant literature. Because of a swiftly appearing painful swel ling, along with complete paralysis of the peroneal nerve, an electrom yogram and a magnetic resonance imaging were performed, in view to con firm the diagnosis and to clarify cyst topography. Results Removal of the cyst led to healing with complete recovery of the peroneal nerve w ithin three months. Discussion 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 imp ossible. It seems preferable to make a longitudinal incision in the ne rve to lay the tumor flat. Indeed, everything possible should be dent to find, then ligature, the pedicle which passes by the articular nerv e ending of the peroneal nerve in order to avoid recurrence. Extraneur al 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. Conclusion In all cases, recurrence is not infrequent. Longer the delay before intervention is less satisfactory the recovery will be.