We undertook a retrospective analysis of 306
procedures on 233 patients, with a mean age of 12 years (1 to 21),
in order to evaluate the use of somatosensory evoked potential (SSEP)
monitoring for the early detection of nerve compromise during external
fixation procedures for limb lengthening and correction of deformity.
Significant SSEP changes were identified during 58 procedures (19%).
In 32 instances (10.5%) the changes were transient, and resolved
once the surgical cause had been removed. The remaining 26 (8.5%)
were analysed in two groups, depending on whether or not corrective
action had been performed in response to critical changes in the
SSEP recordings. In 16 cases in which no corrective action was taken,
13 (81.2%, 4.2% overall) developed a post-operative neurological
deficit, six of which were permanent and seven temporary, persisting
for five to 18 months. In the ten procedures in which corrective
action was taken, four patients (40%, 1.3% overall) had a temporary
(one to eight months) post-operative neuropathy and six had no deficit. After appropriate intervention in response to SSEP changes, the
incidence and severity of neurological deficits were significantly
reduced, with no cases of permanent neuropathy. SSEP monitoring
showed 100% sensitivity and 91% specificity for the detection of
nerve injury during external fixation. It is an excellent diagnostic
technique for identifying nerve lesions when they are still highly
reversible.
A percutaneous supramalleolar osteotomy with multiple drill holes and closed osteoclasis was used to correct rotational deformities of the tibia in patients with cerebral palsy. The technique is described and the results in 247 limbs (160 patients) are reported. The mean age at the time of surgery was 10.7 years (4 to 20). The radiographs were analysed for time to union, loss of correction, and angulation at the site of the osteotomy. Bone healing was obtained in all patients except one in a mean period of seven weeks (5 to 12). Malunion after loss of reduction at the site of the osteotomy developed in one tibia. Percutaneous supramalleolar osteotomy of the tibia is a safe and simple surgical procedure.
