Method:

We reviewed the notes, surgical and IOM charts of all patients who underwent spinal surgery with the use of cortical and cervical SSEPs, as well as upper/lower limb transcranial electrical MEPs under the senior author. We recorded IOM events which we categorised as true, transient true and false (+) or (−). We correlated the IOM events with surgical or anaesthetic incidents.

Methods and Results

TSE T2 three dimensional aquisition MRI studies reconstructed with OsiriX DICOM viewer from 32 patients were used. Patients included were a series of consecutive cases with either suspected spinal stenosis or low back pain. A total of 97 disc levels were studied and axial reconstructions were made at 0°, +10°, +20°, +30° relative to the disc space orientation. For each image, DSCA was digitally measured and a severity grade was assigned by two observers according to the recently-published 4-point (A-D) morphological grading system. Interobserver kappa score was 0.71. Statistical analysis of DSCA measurements was performed using kappa and t-tests. Comparing DCSA between 0° at each level and +10°, +20° and +30° slice orientation, a significant increase in surface area was found in each case (P<0.0001). % change in DSCA combining all disc levels comparing 0° and +10°: range -15.48% to +31.89% (SD 18.40%); 0° and +20°: range -24.00% to +143.82% (SD 20.45%); 0° and +30°: range -29.35% to +231.13% (SD 26.52%). At 13 disc levels, DSCA was <100mm² at 0°, but changed to >100mm² in three cases by a +10° increase, in five cases by a +20° increase and in 10 cases by a +30° increase. In only two out of 97 levels studied did the morphological grading change as the angle increased, one of which was not amongst those above (change in DSCA from <100mm² to >100mm²).

Methods

The IOM wave-recordings, event-logs and reports of all spinal deformity cases conducted by a team of clinical physiologists from April to June 2009 (Group 1) were reviewed retrospectively by the same, experienced clinical neurophysiologist, (MG).

Interventions were then agreed. The first was to alter the IOM report document to drop down menus. The second was to arrange a series of teaching sessions for the clinical physiologists on a variety of aspects of IOM. Finally during these teaching sessions recent cases were brought to review in an informal setting to discuss.

Following implementation of the interventions a further review from April to June 2010 (Group 2) was carried out in the same manner.

The clinical physiologists did not know the time periods over which the review would be taking place.