Correlation of listhesis on upright radiographs and central lumbar spinal canal stenosis on supine MRI: is it possible to predict lumbar spinal canal stenosis?

Minimally Invasive Trans-sacral Canal Plasty for Lumbar Canal Stenosis

Objective The elderly population is increasing in Japan. Along with the increase in the elderly population, the number of patients with lumbar degenerative diseases is also on the rise. In general, elderly patients tend to have more complications and are at higher risk for surgery. Many elderly people suffer from lumbar degenerative disease. We reviewed our initial experience with trans-sacral canal plasty (TSCP) for patients with lumbar spinal canal stenosis and examined the pertinent literature for this report. Methods An analytical observational study was performed on 120 patients with lumbar spinal canal stenosis who underwent TSCP at our single institution from March 2019 to October 2021. These patients had leg pain and/or lower back pain due to degenerative lumbar disease. Patients who had coagulation abnormality, pregnancy, contrast allergy, pyogenic spondylitis, or spinal metastasis were excluded. Results Immediately after TSCP, the average Visual Analog Scale (VAS) score for back pain improved from 58.2 to 29.3, and for leg pain from 72.0 to 31.3. Two years after TSCP, the average VAS score for back pain increased slightly and the average score for leg pain remained almost the same. Additional surgery was performed in 37 of 120 (31%) patients who underwent TSCP. The additional surgery group had significantly worse back pain at one and three months postoperatively than the conservative treatment group. The additional surgery group had significantly worse leg pain immediately after TSCP and at one and three months postoperatively than the conservative treatment group. Logistic regression analysis demonstrated that a decreased spinal canal area (OR 0.986, p = 0.039) was associated with additional surgery. Conclusions We reviewed the outcomes of TSCP at our hospital. The average VAS score for back pain and leg pain improved. However, 31% of patients who underwent TSCP required additional surgery. It was found that the spinal canal area was a major factor in the need for additional surgery.

Comparison of ligamentum flavum thickness between central and lateral lesions in a patient with central lumbar spinal canal stenosis

Thickened ligamentum flavum has been considered as a major cause of central lumbar spinal canal stenosis (CLSCS). Previous studies have demonstrated that ligamentum flavum thickness (LFT) is correlated with aging, degenerative spinal stenosis, and disc degeneration. Thus, hypertrophy of the ligamentum flavum is a major cause of CLSCS, and measurement of LFT has been considered a morphologic parameter in the diagnosis of CLSCS. To our knowledge, comparison of LFT between central and lateral lesions has not been reported. In addition, no research has analyzed best clinical cutoff values of central ligament flavum thickness (CLFT) and lateral ligament flavum thickness (LLFT). This study aimed to compare CLFT with LLFT in patients with CLSCS and further compare the CLFT and LLFT findings between the 2 groups to analyze LFT variation. Both CLFT and LLFT samples were collected from 101 participants with CLSCS and from 103 participants in the control group who underwent lumbar magnetic resonance imaging without evidence of CLSCS. Axial T2-weighted lumbar magnetic resonance scans were acquired at the L4 to 5 facet joint level from each participant. Average CLFT value was 2.25 ± 0.51 mm in the control group and 4.02 ± 0.74 mm in the CLSCS group. Average LLFT value was 2.50 ± 0.51 mm in the control group and 3.38 ± 0.66 mm in the CLSCS group. CLSCS patients had significantly higher CLFT and LLFT (both P < .001). Regarding the validity of both CLFT and LLFT as predictors of CLSCS, a receiver operating characteristic estimation revealed that the most suitable cutoff value for CLFT was 3.10 mm, with sensitivity of 95.0%, specificity of 94.2%, and an area under the curve of 0.97. The best cut-off value of LLFT was 2.92 mm, with sensitivity of 78.2%, specificity of 77.7%, and area under the curve of 0.87. We have 4 important new findings: The mean CLFT is significantly lower than that of the mean LLFT in the normal control group; CLFT and LLFT are both significantly associated with CLSCS; Increase rate of CLFT is faster than that of LLFT in the CLSCS group; and CLFT is a more sensitive measurement parameter to predict CLSCS than LLFT.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Magnetic Resonance Imaging Proxies for Segmental Instability in Degenerative Lumbar Spondylolisthesis Patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim was to investigate whether findings on magnetic resonance imaging (MRI) can be proxies (MRIPs) for segmental instability in patients with degenerative lumbar spinal stenosis (LSS) and/or degenerative spondylolisthesis (LDS) L4/L5.

BACKGROUND

LDS has a heterogeneous nature. Some patients have a dynamic component of segmental instability associated with LDS. Studies have shown that MRI can show signs of instability.

METHODS

Patients with LSS or LDS at L4/L5 undergoing decompressive surgery±fusion from 2010 to 2017, with preoperative standing lateral spine radiographs and supine lumbar MRI and enrolled in Danish national spine surgical database, DaneSpine. Instability defined as slip of >3 mm on radiographs. Patients divided into two groups based upon presence of instability. Outcome measures: radiograph: sagittal slip (mm). MRIPs for instability: sagittal slip >3 mm, facet joint angle (°), facet joint effusion (mm), disk height index (%), and presence of vacuum phenomena. Optimal thresholds for MRIPs was determined by receiver operating characteristic (ROC) curves and area under the curve (AUC). Logistic regression to investigate association between instability and MRIPs.

RESULTS

Two hundred thirty-two patients: 47 stable group and 185 unstable group. The two groups were comparable with regard to baseline patient-reported outcome measures. Thresholds for MRIPs: bilateral facet joint angle ≥46°; bilateral facet effusion ≥1.5 mm and disk height index ≥13%. Logistic regression showed statistically significant association with MRIPs except vacuum phenomena, ROC curve AUC of 0.951. By absence of slip on MRI logistic regression showed statistically significant association between instability on radiograph and the remaining MRIPs, ROC curve AUC 0.757.

CONCLUSION

Presence of MRIPs for instability showed statistically significant association with instability and excellent ability to predict instability on standing radiograph in LSS and LDS patients. Even in the absence of slip on MRI the MRIPs had a good ability to discriminate presence of instability.

Accurate prediction of lumbar microdecompression level with an automated MRI grading system

OBJECTIVE

Lumbar spine MRI interpretations have high variability reducing utility for surgical planning. This study evaluated a convolutional neural network (CNN) framework that generates automated MRI grading for its ability to predict the level that was surgically decompressed.

MATERIALS AND METHODS

Patients who had single-level decompression were retrospectively evaluated. Sagittal T2 images were processed by a CNN (SpineNet), which provided grading for the following: central canal stenosis, disc narrowing, disc degeneration, spondylolisthesis, upper/lower endplate morphologic changes, and upper/lower marrow changes. The grades were used to calculate an aggregate score. The variables and the aggregate score were analyzed for their ability to predict the surgical level. For each surgical level subgroup, the surgical level aggregate scores were compared with the non-surgical levels.

RESULTS

A total of 141 patients met the inclusion criteria (82 women, 59 men; mean age 64 years; age range 28-89 years). SpineNet did not identify central canal stenosis in 32 patients. Of the remaining 109, 96 (88%) patients had a decompression at the level of greatest stenosis. The higher stenotic grade was present only at the surgical level in 82/96 (85%) patients. The level with the highest aggregate score matched the surgical level in 103/141 (73%) patients and was unique to the surgical level in 91/103 (88%) patients. Overall, the highest aggregate score identified the surgical level in 91/141 (65%) patients. The aggregate MRI score mean was significantly higher for the L3-S1 surgical levels.

CONCLUSION

A previously developed CNN framework accurately predicts the level of microdecompression for degenerative spinal stenosis in most patients.

Please be upstanding - A narrative review of evidence comparing upright to supine lumbar spine MRI

OBJECTIVES

The objective of the review was to examine the evidence comparing upright to supine MRI of the lumbar spine.

KEY FINDINGS

A literature search identified 14 articles comparing data where subjects had been scanned in both supine and upright positions on the same scanner. Lumbar spine anatomy is dynamic and therefore subject to morphological changes when transitioning from the supine to the upright position. There is strong evidence to suggest structural changes in spinal morphology due to radiographic positioning, and that upright positioning is better for evaluating spondylolisthesis.

CONCLUSION

It has been demonstrated that the scanning position is important in the outcome of the MRI examination of the lumbar spine. With this in mind, it would be beneficial for guidance to be written and adopted to improve the consistency and quality of scanning.

IMPLICATIONS FOR PRACTICE

As upright MRI occupies a niche in the scanning sector, many professionals are unaware of its capabilities. This article aims to increase awareness of the use of upright MRI in evaluating the lumbar spine.