Introduction: Intra‐operative skeletal traction is used to facilitate coronal plane deformity correction. Its use can be associated with spinal cord stretching and ischemia with resultant electrophysiological changes. The prevalence of such changes, its clinical significance and safety is unknown.
Methods: Radiographs and charts were reviewed of 38 consecutive scoliosis patients treated with intraoperatives skull‐femoral traction between 2005 and 2008. All patients had SSEP and MEP monitoring.
Results: After exclusion of two patients with non‐traction related changes, 37 consecutive procedures in 36 patients with a mean age of 15.4 (11.4–17.9) years were reviewed. The mean skull traction was 8.6kg(6.8–11.3) and femoral traction was 22.3 kg (13.6–31.7). Intra‐operative MEP changes occurred in 18/37(48%) and SEP changes in 1 (2.7%) procedure. The 18 cases with MEP changes had a mean Cobb of 86°, curve flexibility index of 0.14, and 41% correction with traction compared to 70°, 0.27, and 50% in the 19 cases without MEP changes (p<0.05). Intra‐operative interventions were performed in response to the changes in MEP resulting in complete recovery in 10/18(55%), complete unilateral recovery with partial contralateral recovery in 6(33%) and incomplete bilateral recovery in 2(11%) patients. There were no patients with unrecordable MEP or SSEP amplitudes at wound closure. There were no post‐operative neurological deficit
Conclusion: Intra‐operative traction is associated with frequent abnormalities in MEP monitoring. The thoracic location of the major curve, mean Cobb angle of 86°, and increased rigidity are risk factors for changes in MEP monitoring with traction. The presence of any MEP recordings at closure was associated with normal neurological function. SSEP should not be used as the sole means of scoliosis monitoring.
Significance: The presence of any MEP recordings at closure was associated with normal neurological function. SSEP alone is insufficient in accurately monitoring scoliosis correction.