Methods: Clinical and neuromonitoring data of 207 consecutive adult patients who underwent cervical spine surgeries at multiple surgical centers using bimodal IONM were analyzed. Signal changes were divided into three groups. Group 0 had transient signal changes in either MEPs or SSEPs, group 1 had sustained unimodal changes, and group 2 had sustained changes in both MEPs and SSEPs. The incidences of true neurological deficits in each group were recorded. Results: A total of 25% (52/207) had IONM signal alerts. Out of these signal drops, 96% (50/52) were considered to be false positives. Groups 0 and 1 had no incidence of neurological deficits, while group 2 had a 29% (2/7) rate of true neurological deficits. The sensitivities of both MEP and SSEP were 100%. SSEP had a specificity of 96.6%, while MEP had a lower specificity at 76.6%. C5 palsy rate was 6%, and there was no correlation with IONM signal alerts (p=0.73). Conclusions This study shows that we can better predict its clinical significance by dividing IONM signal drops into three groups. A sustained, bimodal (MEP and SSEP) signal drop had the highest risk of true neurological deficits and warrants a high level of caution. There were no clear risk factors for false-positive alerts but there was a trend toward patients with cervical myelopathy.

Methods: Clinical and neuromonitoring data of 207 consecutive adult patients who underwent cervical spine surgeries at multiple surgical centers using bimodal IONM were analyzed. Signal changes were divided into three groups. Group 0 had transient signal changes in either MEPs or SSEPs, group 1 had sustained unimodal changes, and group 2 had sustained changes in both MEPs and SSEPs. The incidences of true neurological deficits in each group were recorded. Results: A total of 25% (52/207) had IONM signal alerts. Out of these signal drops, 96% (50/52) were considered to be false positives. Groups 0 and 1 had no incidence of neurological deficits, while group 2 had a 29% (2/7) rate of true neurological deficits. The sensitivities of both MEP and SSEP were 100%. SSEP had a specificity of 96.6%, while MEP had a lower specificity at 76.6%. C5 palsy rate was 6%, and there was no correlation with IONM signal alerts (p=0.73). Conclusions This study shows that we can better predict its clinical significance by dividing IONM signal drops into three groups. A sustained, bimodal (MEP and SSEP) signal drop had the highest risk of true neurological deficits and warrants a high level of caution. There were no clear risk factors for false-positive alerts but there was a trend toward patients with cervical myelopathy.

INTRODUCTIONThis study aimed to evaluate the clinical and radiological outcomes, and safety and efficacy of percutaneous pedicle screw fixation (PPSF) in the treatment of thoracolumbar burst fractures.

METHODSThis was a retrospective review of patients with thoracolumbar burst fractures treated with PPSF in a single hospital from 2010 to 2011. Baseline data included patient demographics, mechanism of injuries, fracture level, neurologic status and the number of percutaneous screws inserted. Kyphotic angle correction, vertebral body height restoration and mid-sagittal canal diameter improvement were used to assess radiological outcome. Screw misplacement, operative complications, functional improvement (ASIA score) and pain score on visual analogue scale were used to assess safety and clinical outcomes.

RESULTS21 patients with 25 thoracolumbar burst fractures were treated with 134 percutaneous screws. There was significant improvement in kyphotic angle correction (mean difference 6.1 degrees, p = 0.006), restoration of anterior and posterior vertebral height (mean difference 19.7%, p < 0.01 and mean difference 6.6%, p = 0.007, respectively) and mid-sagittal canal diameter (mean difference 15.6%, p = 0.007) on discharge. These improvements remained statistically significant at six months post operation for restoration of anterior vertebral body height (mean difference 9.8%, p = 0.05) and mid-sagittal diameter (mean difference 30.0%, p < 0.01).

CONCLUSIONIn this first local review, we have shown that PPSF is a relatively safe and effective technique for treating selected thoracolumbar burst fractures, and that it yields satisfactory results. However, its long-term outcome and efficacy need to be further evaluated.

Adult ; Aged ; Bone Screws ; Female ; Fracture Fixation, Internal ; adverse effects ; instrumentation ; methods ; Humans ; Lumbar Vertebrae ; injuries ; Male ; Middle Aged ; Minimally Invasive Surgical Procedures ; Radiography ; Retrospective Studies ; Safety ; Singapore ; Spinal Fractures ; diagnostic imaging ; surgery ; Thoracic Vertebrae ; injuries ; Treatment Outcome