Reliability of ankle clonus evaluation for monitoring neural-tract integrity in pediatric spinal deformity surgery under different anesthetics protocols.

Background: Although the ankle clonus test is a pathological finding in neurological examination, it may temporarily occur in neurologically intact individuals during awakening from anesthesia. Some studies suggest it as a marker indicating neural tract integrity in pediatric spinal deformity surgery. This study aims to investigate the consistency of the ankle clonus test under different anesthesia protocols in pediatric patients with spinal deformities.

Methods: A total of 39 patients diagnosed with Adolescent Idiopathic Scoliosis or Scheuermann Kyphosis were enrolled to this prospective study. Patients were divided into three groups based on the anesthesia protocol used. In Group I and Group II, two different anesthetic agents (pentothal vs. propofol) were administered, while Group III received Total Intravenous Anesthesia. All patients underwent surgery with pedicle screw constructs using a standard posterior approach. The presence of clonus was recorded during awakening.

Results: Bilateral ankle clonus was observed in 10 patients (76.9%) in Group 1, six patients (46.1%) in Group II, and seven patients (53.8%) in Group III. Clonus was absent in 16 patients (41%) across all groups. There was no significant association between the presence of ankle clonus and factors such as group assignment, duration of surgery, level of instrumentation, or blood loss. No neurological deficits were observed in any patient during the postoperative period.

Conclusion: The ankle clonus test is not a reliable method for monitoring neurological deficits during spinal surgery. It is not exactly known how such myoclonic contractions occur or how the pathway is inhibited or activated.