The Nerve Root Sedimentation Sign in transverse magnetic resonance imaging has been shown to discriminate well between selected patients with and without lumbar spinal stenosis (LSS), but the performance of this new test, when used in a broad patient population, is not yet known (Barz et al. 2010).

We conducted a retrospective study of consecutive patients with suspected LSS from 2004–2006, before the sign had been described, to assess its association with health outcomes. Based on clinical and radiological diagnostics, patients had been treated with decompression surgery or conservative treatment (physical therapy, oral pain medication). Changes in the Oswestry Disability Index (ODI) from baseline to 24 month follow-up were compared between Sedimentation Sign positives and negatives in both treatment arms.

Of the 146 included patients (52% female, mean age 59 yrs), 71 underwent surgery. Baseline ODI in this treatment arm was 52%, the sign was positive in 44 patients (mean ODI improvement 25 points) and negative in 27 (ODI improvement 24), with no significant difference between groups. In the 75 patients of the conservative treatment arm, baseline ODI was 44%, the sign was negative in 45 (ODI improvement 17), and positive in 30 (ODI improvement 5). Here a positive sign was associated with a smaller ODI improvement compared with sign negatives (t-test, p=0.003).

This study allowed an unbiased clinical validation of the Sedimentation Sign by avoiding it influencing treatment selection. In the conservative treatment arm a positive sign identifies a group of patients who are less likely to benefit. In these cases, surgery might be effective; however, this needs confirmation in prospective studies.

Objectives

Juxtafacet cysts of the spine can cause radicular pain, neurological symptoms and are often associated with spinal degeneration. The mainstay of treatment of juxtafacet cysts is surgical resection with laminotomy and resection of the cyst. Other methods, including epidural steroid and facet injections are mostly temporarily effective. The aim of this study is the sufficient decompression with reduced traumatization and destabilization with the full-endoscopic interlaminar and transforaminal technique.

Introduction: Lumbar spinal stenosis (LSS) is diagnosed by a history of claudication, clinical investigation, treadmill test, and cross sectional area (CSA) in MRI or CT. Because commonly used radiological findings not always correlate with clinical symptoms, additional parameters with high specificity and sensitivity are needed.

Methods: Prospective study of dorsal lumbar nerve root sedimentation in MRI scans in supine position of 2 groups of 100 consecutive patients each between 01/2007 – 12/2007. Patients in group 1 had non-specific low back pain (LBP), no claudication, and a CSA above 120 mm2 (LBP group); patients in group 2 showed claudication with or without LBP and a CSA below 80 mm2 (LSS group). We excluded patients with a previous spine surgery. In addition to the sedimentation sign, in both groups VAS, ODI, and walking distance in the treadmill test were measured.

Results: The sedimentation sign was positive in 94 patients in the LSS group but in no patient in the LBP group, showing a specificity of 100%, a sensitivity of 94%, and an accuracy of 97%. There was no difference between segmental levels L1 – L5. Walking distance in the LSS group was shorter than in the LBP group (67 m vs. > 1000 m; p< 0.001). There were no significant differences between both groups regarding VAS and ODI.

Conclusion: In patients without LSS during MRI in supine position lumbar nerve roots sediment due to gravity to the dorsal part of the dural sac leading to a positive sedimentation sign. This sedimentation is not observed in patients with LSS. Therefore, a negative sedimentation sign is a predictor of LSS in patients without prior spine surgery with a high specificity and sensitivity. Level S1 and below were excluded in our study because nerve roots S1 and S2 leave the dural sac in a ventral position inhibiting sedimentation to the dorsal part of the dural sac. The sedimentation sign is a reliable additional diagnostic parameter in patients with LSS.

Background context: Surgical treatment of lumbar spinal stenosis is one of the most frequent procedures in spinal surgery. Nevertheless, the predictive quality of instruments like treadmill test and MRI has not yet been clearly defined for the lumbar spinal stenosis.

Purpose: Objective of this study was to verify correlations between treadmill test and MRI findings in the narrowest spinal segment.

Methods: In a prospective study (EBM-level 3) 25 patients with inpatient treatment for lumbar spinal stenosis were investigated between 01/2005 and 06/2005. Exclusion criteria were a reduced walking capacity for other reasons (e.g. gonarthrosis). Treadmill tests were performed following the protocol by Deen. Patients estimated their maximum walking distance before performing the tests. Area of the dural sac, area of the neuroforamina and disc height at the dorsal margin were examined by MRI for the narrowest spinal segment. VAS and ODI were used as clinical assessment instruments.

Outcome Measures: The median age of patients was 67 yrs (IQR 58–73 yrs) with 44 % females. The median distance reached in the treadmill test was 70 m (IQR 30–135 m), the median estimated maximum walking distance 200 m (IQR 100–300 m). In the narrowest spinal segment the median area of the dural sac was 91 mm2 (IQR 65–143 mm2), the median area of the neuroforamina 43 mm2 (IQR 36–51 mm2) and the median disc height 1,4 mm (IQR 0,9–2,5 mm). The median VAS was 7 (IQR 6,5–8) and the median ODI 33 (IQR 32–37).

Results: The distance reached in the treadmill test correlated with the maximum walking distance estimated by the patients (Spearman’s rho=0,62, p=0,001), area of the dural sac (rho=0,54, p=0,006) and disc height (rho=0,45, p=0,03), but not with area of the neuroforamina and VAS. VAS correlated with the disc height (rho=−0,6, p=0,002), but with no other MRI findings.

Conclusions: The distance reached in the treadmill test and MRI findings in the narrowest spinal segment predict the level of clinical symptoms. Possible reasons for the slightly limited predictive quality of MRI findings are that this study did not regard the time of development of the stenosis, that effects of multilevel stenosis were not considered, and that MRI findings in lying position without lordosis might differ from findings in standing position. However, the treadmill test is a valid and highly practicable pre-surgery diagnostic instrument in lumbar spinal stenosis.