Does the presence of the nerve root sedimentation sign on MRI correlate with the operative level in patients undergoing posterior lumbar decompression for lumbar stenosis?

Brief review 1

*Title: Does the presence of the nerve root sedimentation sign on MRI correlate with the operative level in patients undergoing posterior lumbar decompression for lumbar stenosis?

*Authors: Akil Fazal, MD,  Andrew Yoo, BA,  John A. Bendo, MD

*Bibliography: Spine J. 2013 Aug;13(8):837-42.

BACKGROUND CONTEXT:

-Recent research describes the use of a nerve root sedimentation sign to diagnose lumbar spinal stenosis (LSS).

-The lack of sedimentation of the nerve roots (positive sedimentation sign) to the dorsal part of the dural sac is the characteristic feature of this new radiological parameter.

PURPOSE: To demonstrate how the nerve root sedimentation sign compares with other more traditional radiological parameters in patients who have been operated for LSS.

STUDY DESIGN/SETTING: A retrospective chart and image review.

PATIENT SAMPLE: Preoperative MRI were reviewed from 71 consecutive operative patients who presented with LSS and received spinal decompression surgery (2006-2010).

OUTCOME MEASURES: Preoperative T2-weighted MRIs were reviewed for each patient.

METHODS:

▶Measurements

134 vertebral levels (L1-5) were measured for

1)     sedimentation sign

2)     cross-sectional area (CSA)

3)     anterior/posterior (A/P) diameter of the dural sac

4)     thickness of the ligamentum flavum

5)     Fujiwara grade of facet hypertrophy.

-using Surgimap 1.1.2.169 software (Nemaris, Inc., New York, NY, USA)

-Exclusion criteria: 1) previous spine surgeries 2) absence of MRI on extended dynamic range 3) surgeries for primary diagnosis other than LSS

▶Statistical analyses

-using the SPSS 17.0 statistical software (SPSS Inc., Chicago, IL, USA).

-Significance was demonstrated using unpaired t tests and chi-squared tests.

RESULTS: The measurements are listed below.

CONCLUSIONS:

-The sign is most often present in patients who have clinically significant lumbar stenosis and require surgery.

-The sedimentation sign is a new measurement tool that can enable physicians to objectively assess and quantify spinal stenosis.

*Fujiwara grading system: aim to assess the severity of the facet joint osteoarthritis.

REFERENCE: Fujiwara A, Tamai K, Yamato M, et al. The relationshipbetween facet joint osteoarthritis and disc degeneration of the lumbar spine: anMRI study. Eur Spine J 1999;8:396–401.