Introduction. Somatosensory evoked potential (SSEP) monitoring allows for assessment of the spinal cord and susceptible structures during complex spinal surgery. It is well validated for the detection of potential neurological injury but little is known of surgeon's responses to an abnormal trace and its effect on neurological outcome. We aimed to investigate this in spinal deformity patients who are particularly vulnerable during their corrective surgery. Methods. Our institutional neurophysiology database was analysed between 1. st. October 2005 and 31. st. March 2010. Monitoring was performed by a team of trained neurophysiology technicians who were separate from the surgical team. A significant trace was defined as a 50% reduction in trace amplitude or a 10% increase in signal latency. Patients suffering a significant trace event were examined post-operatively by a Consultant Neurologist who was separate from the surgical team. Results. 2386 consecutive operations (F:1719, M:667 median age 16 yrs) were performed in the time period and 72 operations reported a significant trace event (‘red alert’). From these cases 47 (65%) had a clearly documented intervention by the surgeon and 7 patients overall suffered a lasting neurological deficit (0.3%). The most common timing events were during instrumentation (50%) and during correction/distraction (16%). Most common responses were optimisation of patient/monitoring set-up (23%) and adjustment of metalwork (22%). There were 18 wake-up tests performed. We found SSEP monitoring to have a sensitivity of 100%, specificity 97.4%, positive predictive value 14% and negative predictive value 100%. A Chi-square test (p=0.016) was significant suggesting intervention had a beneficial effect on neurological outcome. Conclusion. We would advocate the use of SSEP monitoring in all patients undergoing spinal deformity surgery. These patients tend to be young, neurologically intact pre-operatively and are particularly vulnerable to the large corrective forces their surgery requires

Introduction. Evidence suggests that intra-operative spinal cord monitoring is sensitive and specific for detecting potential neurological injury. However, little is known about surgeons' responses to trace changes and the resultant neurological outcome. Objective. To examine the role of intra-operative somatosensory evoked potential (SSEP) monitoring in the prevention of neurological injury, specifically sensitivity and specificity, and whether the abnormalities were reversible. Methods. 2953 consecutive complex spine operations (male 36% female 64%, median age 25yrs) prospectively performed using spinal cord monitoring at a single institution (2005–2009). All traces and neurophysiological events were prospectively recorded by the neurophysiology technician. All patients with a significant neurophysiology event were examined clinically by a neurologist, separate from the spinal surgery team. Significant trace abnormality was defined as a decrease in signal amplitude of 50% or a 10% increase in latency. Timing of trace abnormality, surgeon's response and prospective neurological outcome were recorded. Sensitivity, specificity, positive/negative predictive value were calculated. A Chi-squared test was performed to assess the impact of intervention on neurological outcome (p < 0.05). Results. 2953 operations involving SSEP monitoring were performed and 106 recorded a significant trace abnormality. This most often occurred during instrumentation and the most common reaction was adjustment of metalwork. SSEP monitoring had a sensitivity of 100%, specificity 97.3%, PPV 24%, NPV 100%. There were 79 false positives and no false negatives in this series. Chi-squared test was not significant (p=0.18) suggesting that intervention might not affect neurological outcome in this cohort. Conclusions. Triggering events are uncommon and the development of a persistent neurological deficit is rare with an incidence of 0.85% in this series of 2953 operations. In the majority of cases detection of a monitoring abnormality prompts a corrective reaction by the surgeon. Of those with an abnormal trace 76% were neurologically normal at follow up

The aim of the study was to assess the validity of the new device [BREVIO] [AEND] [Level 2 evidence] in diagnosing carpal tunnel syndrome in the outpatient setting when used by personnel not trained previously in neurophysiologic methods. We prospectively compared the results from a portable handheld automated electroneurodiagnostic devices (AEND) the BREVIO with those from conventional nerve conduction studies. We calculated specificity and sensitivity. We also studied the limits of agreement and correlation between measured latencies. Patient satisfaction with new device was recorded. Twenty-seven participants (42 hands) were tested. The average age was 56.43 years (38-79). There were 16 females and 11 males. The sensitivity and specificity of the BREVIO as compared to conventional methods were 80% and 75% using distal motor latencies; using distal sensory latencies the sensitivity and specificity were 90% and 60% respectively. The limits of agreement between the sensory and motor latencies using Bland Altman plots were good. Similarly there was good correlation between values measured with the Pearson's correlation coefficient. The position of the baseline cursor was questionable in 19 hands. Repositioning the cursor reduced the number of false positive results which would increase the specificity of the device. The average pain score, VAS on a scale of 1-10, with the BREVIO was 1.69 (1-4) and 3.11(1-5) with conventional testing. The average satisfaction rating on a scale of 1-5 was 1.39 with the BREVIO and 2.73 with the conventional nerve conduction testing. The BREVIO is an interesting device. We recommend its use by untrained persons only under the supervision of someone trained in neurophysiology who is aware of potential pitfalls