We plan to study prospectively study about 200 patients who have attended our OPD department for consultation for lumbosacral radiculopathy in the next two years.   

We will do a thorough clinical examination after noting down the history.  We will study their MRI lumbosacral spine and lateral flexion-extension X-rays for the presence or absence of listhesis.

We will consider spondylolisthesis to be present when vertebral slip is seen greater than three millimeters on lateral standing flexion-extension radiographs.   

For objectively measuring the obliquity of the exiting nerve root, we have described an angle which the exiting nerve root makes with the body of a vertebra.  We will select far lateral sagittal T2 weighted image just lateral to the facet joints or the image which clearly shows exiting nerve roots coming out of intervertebral foramen in an inverted teardrop manner.  We will draw a line parallel to the lower endplate of the vertebra and another line along the exiting nerve root and will measure the angle between these two lines. This we will consider ‘Angle of the obliquity of the exciting nerve root’ 

We will study the correlation of this obliquity of exiting nerve root on lateral sagittal MRI images with spondylolisthesis on standing lumbosacral spine lateral flexion-extension X-rays.

Statistically, we will find out (1) the sensitivity of our test, (2) the specificity of our test, (3) the predictive value of a positive test, and (4) the predictive value of a negative test.  

We may thus be able to prove the correlation between obliquity of the exiting nerve root on MRI and spondylolisthesis on flexion-extension X-rays.

If it can be established then it will become a sign on MRI to diagnose spondylolisthesis with great accuracy and will obviate the need for additional investigation, i.e. lateral flexion-extension X-ray of the lumbosacral spine which at present is considered to be the gold standard to diagnose spondylolisthesis.