Introduction: Tonsillar ectopia and abnomal somatosensory evoked potential (SEPs) have been documented in adolescent idiopathic scoliosis (AIS) patients. The relationship between the position of cerebellar tonsil and SEPs in AIS patients, however, has not been widely studied.
Objectives: To investigate the relationship of abnormal position of the cerebellar tonsil with SEPs study in AIS patients.
Materials and Methods: Sagittal MRI of hindbrain and posterior tibial nerve SEPs (PTN-SEPs) were performed on 171 severe AIS patients undergoing surgical treatment. The PTN-SEPs obtained from 45 age-matched healthy control individuals were used as control. Tonsillar ectopia (TE) was defined as any inferior displacement of the tonsil below the standard refernce BO line. Absence of waveforms, prolongation of peak latency or asymmetrical peak latency of greater than 2.5 SD in the SEPs was defined as pathological. The association of TE and abnormal SEPs for AIS patients was also assessed.
Results: The incidence of TE and abnormal SEPs in AIS patients was 36.8% (63/171) and 36.3(62/171), respectively. Statistical analysis showed no significant correlation between TE and abnormal SEPs. AIS patients with different curve severity showed no difference on the frequency of TE or abnormal SEPs.
Conclusion and Significance: There are TE and abnormal SEPs in a subgroup of AIS patients. The abnormal somatosensory function might be directly caused by the TE alone. Further in depth studies on different severity of AIS with longitudinal follow-up might help to further understand the link and potential contribution to the etiopathgenesis of AIS.