The correlation between exaggerated fluid in lumbar facet joints and degenerative spondylolisthesis: prospective study of 52 patients

MR imaging differentiating features between lytic and degenerative lumbosacral spondylolisthesis

Spondylolisthesis is characterized by the displacement of one vertebral body in relation to the adjacent vertebra. It is commonly observed in the lower lumbar region and can be caused by a variety of factors, including spondylolysis (a fracture in the pars interarticularis) or degenerative disease. Magnetic resonance imaging (MRI) is becoming increasingly popular as the primary modality for evaluation of low back pain and is often used in the absence of radiographs or Computed Tomography. However, it can be challenging for radiologists to differentiate between the two types of spondylolisthesis based on MRI alone. The goal of this article is to identify key imaging features on MRI that can aid radiologists in differentiating between spondylolysis and degenerative spondylolisthesis on MRI. Five key concepts are discussed: the "step-off" sign, the "wide canal" sign, T2 cortical bone signal on MRI, epidural fat interposition, and fluid in the facet joints. The utility, limitations and potential pitfalls of these concepts are also discussed to provide a comprehensive understanding of their use in differentiating between the two types of spondylolisthesis on MRI.

Evolution of lumbar degenerative spondylolisthesis with key radiographic features

Spondylolisthesis is a common finding in middle-aged and older adults with back pain. The pathophysiology of degenerative spondylolisthesis is a subject of controversy regarding not only its etiology but also the mechanisms of its progression. It is theorized that degeneration of the facets and discs can lead to segmental instability, leading to displacement over time. Kirkaldy-Willis divided degenerative spondylolisthesis into three phases: dysfunction, instability, and finally, restabilization. There is a paucity of literature on the unification of the radiological hallmarks seen in spondylolisthesis within these phases. The radiographic features include (1) facet morphology/arthropathy, (2) facet effusion, (3) facet vacuum, (4) synovial cyst, (5) interspinous ligament bursitis, and (6) vacuum disc as markers of dysfunction, instability, and/or restabilization. We discuss these features, which can be seen on X-ray, CT, and MRI, with the intention of establishing a timeline upon which they present clinically. Spondylolisthesis is initiated as either degeneration of the intervertebral disc or facet joints. Early degeneration can be seen as facet vacuum without considerable arthropathy. As the vertebral segment becomes increasingly dynamic, fluid accumulates within the facet joint space. Further degeneration will lead to the advancement of facet arthropathy, degenerative disc disease, and posterior ligamentous complex pathology. Facet effusion can eventually be replaced with a vacuum in severe facet osteoarthritis. Intervertebral disc vacuum continues to accumulate with further cleft formation and degeneration. Ultimately, autofusion of the vertebra at the facets and endplates can be observed. With this review, we hope to increase awareness of these radiographical markers and their timeline, thus placing them within the framework of the currently accepted model of degenerative spondylolisthesis, to help guide future research and to help refine management guidelines.

ChatGPT versus NASS clinical guidelines for degenerative spondylolisthesis: a comparative analysis

BACKGROUND CONTEXT

Clinical guidelines, developed in concordance with the literature, are often used to guide surgeons' clinical decision making. Recent advancements of large language models and artificial intelligence (AI) in the medical field come with exciting potential. OpenAI's generative AI model, known as ChatGPT, can quickly synthesize information and generate responses grounded in medical literature, which may prove to be a useful tool in clinical decision-making for spine care. The current literature has yet to investigate the ability of ChatGPT to assist clinical decision making with regard to degenerative spondylolisthesis.

PURPOSE

The study aimed to compare ChatGPT's concordance with the recommendations set forth by The North American Spine Society (NASS) Clinical Guideline for the Diagnosis and Treatment of Degenerative Spondylolisthesis and assess ChatGPT's accuracy within the context of the most recent literature.

METHODS

ChatGPT-3.5 and 4.0 was prompted with questions from the NASS Clinical Guideline for the Diagnosis and Treatment of Degenerative Spondylolisthesis and graded its recommendations as "concordant" or "nonconcordant" relative to those put forth by NASS. A response was considered "concordant" when ChatGPT generated a recommendation that accurately reproduced all major points made in the NASS recommendation. Any responses with a grading of "nonconcordant" were further stratified into two subcategories: "Insufficient" or "Over-conclusive," to provide further insight into grading rationale. Responses between GPT-3.5 and 4.0 were compared using Chi-squared tests.

RESULTS

ChatGPT-3.5 answered 13 of NASS's 28 total clinical questions in concordance with NASS's guidelines (46.4%). Categorical breakdown is as follows: Definitions and Natural History (1/1, 100%), Diagnosis and Imaging (1/4, 25%), Outcome Measures for Medical Intervention and Surgical Treatment (0/1, 0%), Medical and Interventional Treatment (4/6, 66.7%), Surgical Treatment (7/14, 50%), and Value of Spine Care (0/2, 0%). When NASS indicated there was sufficient evidence to offer a clear recommendation, ChatGPT-3.5 generated a concordant response 66.7% of the time (6/9). However, ChatGPT-3.5's concordance dropped to 36.8% when asked clinical questions that NASS did not provide a clear recommendation on (7/19). A further breakdown of ChatGPT-3.5's nonconcordance with the guidelines revealed that a vast majority of its inaccurate recommendations were due to them being "over-conclusive" (12/15, 80%), rather than "insufficient" (3/15, 20%). ChatGPT-4.0 answered 19 (67.9%) of the 28 total questions in concordance with NASS guidelines (P = 0.177). When NASS indicated there was sufficient evidence to offer a clear recommendation, ChatGPT-4.0 generated a concordant response 66.7% of the time (6/9). ChatGPT-4.0's concordance held up at 68.4% when asked clinical questions that NASS did not provide a clear recommendation on (13/19, P = 0.104).

CONCLUSIONS

This study sheds light on the duality of LLM applications within clinical settings: one of accuracy and utility in some contexts versus inaccuracy and risk in others. ChatGPT was concordant for most clinical questions NASS offered recommendations for. However, for questions NASS did not offer best practices, ChatGPT generated answers that were either too general or inconsistent with the literature, and even fabricated data/citations. Thus, clinicians should exercise extreme caution when attempting to consult ChatGPT for clinical recommendations, taking care to ensure its reliability within the context of recent literature.

Significance of Facet Fluid Index in Anterior Cervical Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To correlate cervical facet fluid characteristics to radiographic spondylolisthesis, determine if facet fluid is associated with instability in cervical degenerative spondylolisthesis, and examine whether vertebral levels with certain facet fluid characteristics and spondylolisthesis are more likely to be operated on.

OVERVIEW OF LITERATURE

The relationship between facet fluid and lumbar spondylolisthesis is well-documented; however, there is a paucity of literature investigating facet fluid in degenerative cervical spondylolisthesis.

METHODS

Patients diagnosed with cervical degenerative spondylolisthesis were identified from a hospital's medical records. Demographic and surgical characteristics were collected through a structured query language search and manual chart review. Radiographic measurements were made on preoperative MRIs for all vertebral levels diagnosed with spondylolisthesis and adjacent undiagnosed levels between C3 and C6. The facet fluid index was calculated by dividing the facet fluid measurement by the width of the facet. Bivariate analysis was conducted to compare facet characteristics based on radiographic spondylolisthesis and spondylolisthesis stability.

RESULTS

We included 154 patients, for whom 149 levels were classified as having spondylolisthesis and 206 levels did not. The average facet fluid index was significantly higher in patients with spondylolisthesis (0.26±0.07 vs. 0.23±0.08, p <0.001). In addition, both fluid width and facet width were significantly larger in patients with spondylolisthesis (p <0.001 each). Cervical levels in the fusion construct demonstrated a greater facet fluid index and were more likely to have unstable spondylolisthesis than stable spondylolisthesis (p <0.001 each).

CONCLUSIONS

Facet fluid index is associated with cervical spondylolisthesis and an increased facet size and fluid width are associated with unstable spondylolisthesis. While cervical spondylolisthesis continues to be an inconclusive finding, vertebral levels with spondylolisthesis, especially the unstable ones, were more likely to be included in the fusion procedure than those without spondylolisthesis.

Facet joint thickness and lumbar instability documented on myelo-computed tomography studies in patients with lumbar degenerative disease

Background

Various indicators of vertebral instability in patients with lumbar degenerative disease can be identified in myelo-computed tomography (CT) studies.

Methods

Of 120 patients, 45 with lumbar degenerative spondylolisthesis (LDS; 53 lumbar lesions) and 75 with lumbar spinal stenosis alone (LSS; 105 lesions) (2015-2019) myelo-CT studies and surgery confirmed the presence of lumbar instability. Myelo-CT findings indicative of instability included facet joint thickness (FJT), fluid in the facet joint, facet tropism, and air in the facet and/or disc.

Results

For the 120 study patients, FJT was significantly elevated in both the LDS and LSS groups.

Conclusion

FJT on myelo-CT is more specific for lumbar instability than other imaging parameters when evaluating LDS. An increase in FJT suggests vertebral instability likely warranting fusion.

Intra-Articular Facet Joint Injection of Normal Saline for Chronic Low Back Pain: A Systematic Review and Meta-Analysis

Objective: This systematic review and meta-analysis compared the patient-reported outcomes of intra-articular facet joint injections of normal saline and selected active substances to identify a more effective agent for treating subacute and chronic low back pain (LBP). Methods: The PubMed, Embase, Scopus, Web of Science, and CENTRAL databases were searched for randomized controlled trials and observational studies published in English. A research quality assessment was performed using ROB2 and ROBINS-I. A meta-analysis was conducted using a random-effects model, and the mean differences (MD) with 95% confidence intervals (CI) in efficacy outcomes, including pain, numbness, disability, and quality of life, were assessed. Results: Of the 2467 potential studies, 3 were included (247 patients). The active substances and normal saline had similar therapeutic effects on pain within 1 h, after 1-1.5 months, and after 3-6 months, with MD and 95% CI of 2.43 and -11.61 to 16.50, -0.63 and -7.97 to 6.72, and 1.90 and -16.03 to 19.83, respectively, as well as on the quality of life after 1 and 6 months. Conclusions: The short- and long-term clinical effects of intra-articular facet joint injections of normal saline are comparable to those of other active substances in patients with LBP.

Factors associated with an increased risk of developing postoperative symptomatic lumbar spondylolisthesis after decompression surgery: an explorative two-centre international cohort study

PURPOSE

Symptomatic lumbar spinal stenosis can be treated with decompression surgery. A recent review reported that, after decompression surgery, 1.6-32.0% of patients develop postoperative symptomatic spondylolisthesis and may therefore be indicated for lumbar fusion surgery. The latter can be more challenging due to the altered anatomy and scar tissue. It remains unclear why some patients get recurrent neurological complaints due to postoperative symptomatic spondylolisthesis, though some associations have been suggested. This study explores the association between key demographic, biological and radiological factors and postoperative symptomatic spondylolisthesis after lumbar decompression.

METHODS

This retrospective cohort study included patients who had undergone lumbar spinal decompression surgery between January 2014 and December 2016 at one of two Spine Centres in the Netherlands or Switzerland and had a follow-up of two years. Patient characteristics, details of the surgical procedure and recurrent neurological complaints were retrieved from patient files. Preoperative MRI scans and conventional radiograms (CRs) of the lumbar spine were evaluated for multiple morphological characteristics. Postoperative spondylolisthesis was evaluated on postoperative MRI scans. For variables assessed on a whole patient basis, patients with and without postoperative symptomatic spondylolisthesis were compared. For variables assessed on the basis of the operated segment(s), surgical levels that did or did not develop postoperative spondylolisthesis were compared. Univariable and multivariable logistic regression analyses were used to identify associations with postoperative symptomatic spondylolisthesis.

RESULTS

Seven hundred and sixteen patients with 1094 surgical levels were included in the analyses. (In total, 300 patients had undergone multilevel surgery.) ICCs for intraobserver and interobserver reliability of CR and MRI variables ranged between 0.81 and 0.99 and 0.67 and 0.97, respectively. In total, 66 of 716 included patients suffered from postoperative symptomatic spondylolisthesis (9.2%). Multivariable regression analyses of patient-basis variables showed that being female [odds ratio (OR) 1.2, 95%CI 1.07-3.09] was associated with postoperative symptomatic spondylolisthesis. Higher BMI (OR 0.93, 95%CI 0.88-0.99) was associated with a lower probability of having postoperative symptomatic spondylolisthesis. Multivariable regression analyses of surgical level-basis variables showed that levels with preoperative spondylolisthesis (OR 17.30, 95%CI 10.27-29.07) and the level of surgery, most importantly level L4L5 compared with levels L1L3 (OR 2.80, 95%CI 0.78-10.08), were associated with postoperative symptomatic spondylolisthesis; greater facet joint angles (i.e. less sagittal-oriented facets) were associated with a lower probability of postoperative symptomatic spondylolisthesis (OR 0.97, 95%CI 0.95-0.99).

CONCLUSION

Being female was associated with a higher probability of having postoperative symptomatic spondylolisthesis, while having a higher BMI was associated with a lower probability. When looking at factors related to postoperative symptomatic spondylolisthesis at the surgical level, preoperative spondylolisthesis, more sagittal orientated facet angles and surgical level (most significantly level L4L5 compared to levels L1L3) showed significant associations. These associations could be used as a basis for devising patient selection criteria, stratifying patients or performing subgroup analyses in future studies regarding decompression surgery with or without fusion.

Excessive Fluid in the Lumbar Facet Joint as a Predictor of Radiological Outcomes After Lateral Lumbar Interbody Fusion

Background Preoperative segmental instability maybe a predictor of postoperative outcomes when treated with lateral lumbar interbody fusion (LLIF). An abnormal collection of fluid within the facet joint has been described as a sign of segmental instability. The potential relationship between this radiological sign and its prognostic relevance for indirect decompression (ID) has not been investigated. Methods Clinical and radiologic results from patients undergoing LLIF in a single institution between 2007 and 2014 were evaluated retrospectively. Patients were divided into two groups: those presenting with excessive fluid (EF) in the facet joints on T2-MRI and those with a normal amount of facet fluid with less than 1mm, which were controls. Radiological parameters were foraminal height, disc height, Cobb angle, and lumbar lordosis. Results A total of 21 patients (43 operated levels) were evaluated pre- and postoperatively. Mean disc height, mean foraminal height, and coronal Cobb angles were statistically significantly improved after LLIF. Only the EF group showed significant improvement in radiological markers after ID; the mean disc height improved from 5.5±2 to 8.8±1mm (p=0.001), mean foraminal height improved from 16.88±3 to 20.53±3mm (p=0.002), and the mean Cobb angle improved from 27.7±16 to 14±13 (p=0.018). Conclusions Patients undergoing LLIF with the radiological findings of EF in the facet joints demonstrated significant improvement in radiological outcomes of ID. Further studies should validate these findings in larger data sets.

MRI T2-mapping of lumbar facet joints is effective for quantitative evaluation of lumbar instability in patients with degenerative lumbar disorders

PURPOSES

To analyze T2 relaxation times of the facet joint by MRI T2-mapping in patients with degenerative lumbar disorders (DLD), and to determine the correlation with lumbar instability in radiographs.

METHODS

We conducted a T2-mapping of the lumbar facet joint using a 1.5 T MRI system. We classified patients with degenerative lumbar disorders scheduled to undergo decompression surgery into groups with stability and instability using radiographs, and compared the T2 relaxation times of the lumbar facet. Lumbar instability was defined as the presence of anterior translation ratio > 5% or disk range of motion (ROM) > 5° in the sagittal plane of SLFE radiographs.

RESULTS

Inclusion criteria were met by 22 patients (45 levels, mean age 64.3 years). Facet effusions had high sensitivity (90%) but had low specificity (28%) for diagnosis of lumbar instability. Mean T2 relaxation times of right and left facet joints are significantly longer (98.4 ms) in the instability group than they are (87.6 ms) in the stability group (p < 0.001). Anterior translation ratio was positively correlated with mean T2 relaxation times of facet joint (R² = 0.493, p < 0.05). From a ROC analysis, the cutoff value of T2 relaxation times for lumbar instability was 98.65 ms (sensitivity 60.0%, specificity 95.7%, AUC 0.763).

CONCLUSIONS

The T2 relaxation times were positively correlated with lumbar instability. This new quantitative evaluation of lumbar facet joint using MRI T2-mapping might be useful to determine lumbar instability.

Research progress of diagnosing methodology for lumbar segmental instability: A narrative review

OBJECTIVE

Lumbar segmental instability (LSI) is due to a pathologic movement of the vertebral body on the vertebra below and often causes clinical symptoms. The study was to achieve the research progress of diagnosing methodology for lumbar segmental instability and help clinicians make treatment choices.

METHODS

The data for this study were collected from the MEDLINE, Springer, Web of Science, PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, Evidence Based Medicine Reviews, VIP, and CNKI. The search terms were integrated as follows: "(∗lumbar instability∗ OR ∗lumbar spondylolisthesis∗) and (∗image∗ or ∗diagnosis∗)". Studies without clear radiographic instable criteria, case reports, letter, and basic research were excluded.

RESULT

In total, 39 articles published met our inclusion criteria. The various modalities were used to diagnosis LSI in these studies included radiographs, facet joint degeneration and physical examination tests.

CONCLUSION

Overall, there have been a variety of researches to develop the diagnosing methodology for LSI, and many have been successful, although no consensus has been reached yet. However, it is believed that the diagnosis of LSI will become easier and more accurate in the near future.

Dynamic morphometric changes in degenerative lumbar spondylolisthesis: A pilot study of upright magnetic resonance imaging

The objectives of this study were to (a) develop a standing MRI imaging protocol, tolerable to symptomatic patients with degenerative spondylolisthesis (DLS), and (b) to evaluate the morphometric changes observed in DLS patients in both supine and standing postures. Patients with single level, Meyerding grade 1 DLS undergoing surgery at a single institution between November 2015 to May 2017 were consented. Patients were imaged in the supine and standing positions in a 0.5 T vertically open MRI scanner (MROpen, Paramed, Genoa, Italy) with sagittal and axial T2 images. The morphometric parameters measured were: cross-sectional area of the thecal sac (CSA), lateral recess height, disc height, degree of anterolisthesis, disc angle, lumbar lordosis, the presence of facet effusion and restabilization signs. Measures from both postures were compared using paired T-test. Associations of posture with the magnitude of change in the various measurements was determined using Pearson correlation or paired T-test when appropriate. All fourteen patients (mean age 64.4 years) included tolerated standing for the time required for image acquisition. All measurements with the exception of lumbar lordosis and disk height showed a statistically significant difference between the postures (p < 0.05). In the standing position, CSA and lateral recess height were reduced by 28% and 50%, respectively. There was no relationship between the change in CSA of the thecal sac and any measures. Standing images acquired in an upright MRI scanner demonstrated postural changes associated with Meyerding grade 1 DLS and images acquisition was tolerated in all patients.

Modifications in lumbar facet joint are associated with spondylolisthesis in the degenerative spine diseases: a comparative analysis

BACKGROUND

Magnetic resonance imaging (MRI) is important in the assessment of degenerative spine disease. However, its role is limited in the identification of spinal instability; therefore, weight-bearing and dynamic studies like X-rays are required. The supine position eliminates the gravitational pull, corrects the vertebral slippage, and opens the facet joints leading to the collection of the synovial fluid into the joint space, which is detected on the MRI and can serve as a marker for instability. We aim to compare the facet fluid, facet hypertrophy, facet angle, and disc degenerative changes among the patients presenting with degenerative spondylolisthesis (DS) and those without.

METHODS

We performed a retrospective review for all the patients treated at our institution from January 2015 to December 2016. Facet Fluid Index (FFI) (ratio of facet fluid width and facet joint width) was calculated to assess the joint fluid. The percentage of spondylolisthesis was measured on X-rays. Each radiological parameter was compared between the two groups, i.e., patients with DS and patients without DS. A p value < 0.05 was considered significant.

RESULTS

In total, 61 patients, 28 with DS and 33 without DS, were enrolled. Baseline characteristics were similar in the two groups (p > 0.05). The average values of FFI, facet fluid width, and the difference between the superior and inferior facet were significantly higher in the group with instability (p < 0.05). Multivariate analysis demonstrated a 4.44 (95% confidence interval [CI] 2.03-5.365) times increase in the odds of instability with a unit increase in FFI, p < 0.0001.

CONCLUSIONS

We report a positive linear correlation between the facet joint effusion and facet hypertrophy on MRI and the percentage of vertebral translation on X-ray. Prospective studies will determine if these markers can play a role in predicting spinal instability.

Flexion-extension standing radiographs underestimate instability in patients with single-level lumbar spondylolisthesis: comparing flexion-supine imaging may be more appropriate

Background

Generally, most spine surgeons agree that increased segmental motion viewed on flexion-extension radiographs is a reliable predictor of instability; however, these views can be limited in several ways and may underestimate the instability at a given lumbar segment.

Methods

Consecutively collected adult (≥18 years old) patients with symptomatic single-level lumbar spondylolisthesis were reviewed from a two-surgeon database from 2015 to 2019. Routine standing lumbar X-rays (neutral, flexion, extension) and supine lumbar MRI (sagittal T2-weighted imaging sequence) were performed. Patients were excluded if they had prior lumbar surgery, missing radiographic data, or if the time between X-rays and MRI was >6 months.

Results

All 39 patients with symptomatic, single-level lumbar spondylolisthesis were identified. The mean age was 57.3±16.7 years and 66% were female. There was good intra- and inter-rater reliability agreement between measured values on the presence of instability. The slip percentage (SP) difference was significantly highest in the flexion-supine (FS) (5.7 mm, 12.3%) and neutral standing-supine (NS) (4.3 mm, 8.7%) groups, both of which were significantly higher compared with the flexion-extension (FE) group (1.8 mm, 4.5%, P<0.001). Ventral instability based on SP >8% was observed more frequently in FS (79.5%) and NS (52.6%) groups compared with FE group (16.7%, P<0.001). No statistically significant correlation was found between SP and disc angle for all radiographic views.

Conclusions

Comparing standing lateral and flexion X-rays with supine MRIs provides higher sensitivity to assess instability than standard flexion-extension radiographs. The FS and NS comparisons also show greater slip percentage differences at higher slip grades, but not at different lumbar levels. These changes are not dependent on age or gender.

Overreporting of the disc herniation in lumbar spine MRI scans performed for patients with spondylolisthesis

BACKGROUND

Spondylolisthesis is often misdiagnosed on magnetic resonance imaging (MRI) as the slip may reduce to a normal alignment when the patient lies supine. Often, disc herniation is reported at the level of spondylolisthesis.

PURPOSE

To determine the incidence rates of disc herniation at the level of spondylolisthesis.

MATERIAL AND METHODS

This is a retrospective study included 258 consecutive patients with spondylolisthesis who had lumbar spine MRI. The archived reports were collectively put in Group 1. A musculoskeletal radiologist and a spine surgeon reviewed the imaging studies together. Their readings were referred to as Group 2. The findings of both groups were compared to evaluate whether disc herniation was overreported.

RESULTS

Group 1 reported findings of true disc herniation in 112 (41.6%) cases and pseudo disc herniation or no findings of disc herniation at the level of spondylolisthesis in 157 (58.4%) cases. Group 2 reported findings of a true disc herniation in 25 (9.3%) cases and pseudo disc herniation or no findings of disc herniation in the remaining 244 (90.7%) cases. There was a statistically significant difference in the reporting rates between these two groups (P < 0.02). The most overreported finding was the disc bulging (P < 0.01).

CONCLUSION

The current study showed overreporting of disc herniation in lumbar spine MRI scans performed for patients with established spondylolisthesis. The majority of disc pathology at the level of spondylolisthesis are pseudo disc rather than a true disc herniation. An accurate diagnosis is vital in planning surgical intervention.

IMAGE CORRELATION BETWEEN FACET EFFUSION AND LUMBAR INSTABILITY

ABSTRACT Objective To assess the incidence of facet effusion in lumbosacral spine magnetic resonance imaging (MRI) and the relationship with radiographic segmental instability in patients submitted to spinal surgery. Methods Retrospective cohort study of patients submitted to lumbosacral spine surgery over a period of three years, through the evaluation of dynamic radiographs (X-ray) motion and facet effusion in axial section of MRI. Instability was defined as vertebral translation > 3 mm or intervertebral angle > 10º, and facet effusion as fluid in the facet joints > 1.5 mm. Results The total number of patients that fulfilled the criteria for analysis was 244, of which 47 presented movement (≤ 3 mm) and 31 presented excessive movement (> 3 mm), 115 had facet effusion (≤ 1.5 mm) and 46 presented excessive fluid (> 1.5 mm). Statistical analysis did not demonstrate a significant association between increased segmental movement and facet effusion (p = 0.150). Conclusions The total incidence of facet effusion was 47.1% and the excessive fluid was 18.9%.There was no association between facet effusion in MRI and instability in dynamic X-ray. MRI does not replace dynamic X-ray in flexion and extension in the evaluations of lumbar instability. Level of evidence III; Retrospective Cohort.

Determination of dynamic instability in lumbar spondylolisthesis using flexion and extension standing radiographs versus neutral standing radiograph and supine MRI

OBJECTIVE

In this study the authors sought to compare the proportion of patients with lumbar spondylolisthesis detected to have dynamic instability based on flexion and extension standing radiographs versus neutral standing radiograph and supine MRI.

METHODS

This was a single-center retrospective study of all consecutive adult patients diagnosed with spondylolisthesis from January 1, 2013, to July 31, 2018, for whom the required imaging was available for analysis. Two independent observers measured the amount of translation, in millimeters, on supine MRI and flexion, extension, and neutral standing radiographs using the Meyerding technique. Interobserver and intraobserver correlation coefficients were calculated. The difference in amount of translation was compared between 1) flexion and extension standing radiographs and 2) neutral standing radiograph and supine MRI. The proportion of patients with dynamic instability, defined as a ≥ 3 mm difference in the amount of translation measured on different imaging modalities, was reported. Correlation between amount of dynamic instability and change in back pain and leg pain 1 year after decompression and instrumented fusion was analyzed using multivariate regression analysis.

RESULTS

Fifty-six patients were included in this study. The mean patient age was 57.1 years, and 55.4% of patients were female. The most commonly affected levels were L4-5 (60.7%) and L5-S1 (30.4%). The average translations measured on flexion standing radiograph, extension standing radiograph, neutral standing radiograph, and supine MRI were 12.5 mm, 11.9 mm, 10.1 mm, and 7.2 mm, respectively. The average difference between flexion and extension standing radiographs was 0.58 mm, with dynamic instability detected in 21.4% of patients. The average difference between neutral standing radiograph and supine MRI was 3.77 mm, with dynamic instability detected in 60.7% of patients. The intraobserver correlation coefficient ranged from 0.77 to 0.90 mm. The interobserver correlation coefficient ranged from 0.79 to 0.86 mm. In 44 patients who underwent decompression and instrumented fusion, the amount of dynamic instability between standing and supine imaging was significantly correlated with change in back pain (p < 0.001) and leg pain (p = 0.05) at the 12-month postoperative follow-up. There was no correlation between amount of dynamic instability between flexion and extension standing radiographs and postoperative back pain and leg pain.

CONCLUSIONS

More patients were found to have dynamic instability by using neutral standing radiograph and supine MRI. In patients who received decompression and instrumented fusion, there was a significant correlation between dynamic instability on neutral standing radiograph and supine MRI and change in back pain and leg pain at 12 months.

Management of symptomatic degenerative low-grade lumbar spondylolisthesis

Degenerative low-grade lumbar spondylolisthesis is the most common form of spondylolisthesis.

The majority of patients are asymptomatic and do not require surgical intervention.

Symptomatic patients present with a combination of lower back pain, radiculopathy and/or neurogenic claudication and may warrant surgery if non-operative measures fail.

There is widespread controversy regarding the indications for surgery and appropriate treatment strategies for patients with this type of spondylolisthesis.

This article provides a comprehensive evidence-based review of the available literature to support the management of degenerative low-grade spondylolisthesis.

Cite this article: EFORT Open Rev 2018;3:620-631. DOI: 10.1302/2058-5241.3.180020.

Magnitude of dural tube compression does not show a predictive value for symptomatic lumbar spinal stenosis for 1-year follow-up: a prospective cohort study in the community

Background

The North American Spine Society states that lumbar spinal stenosis (LSS) is a clinical syndrome, and there is insufficient evidence to make a recommendation for or against a correlation between clinical symptoms or function and the presence of anatomic narrowing of the spinal canal on MRI. The main purpose of this study was to assess the influence of the magnitude of dural tube compression on MRI on LSS symptoms at the cross-sectional and 1-year follow-up.

Methods

This was a prospective cohort study of 459 participants who were assessed for LSS using a questionnaire and conventional MRI of the lumbar spine. After 1 year, 335 subjects (follow-up rate 73.0%) were assessed for LSS using the same questionnaire. The time course of the clinical subjective symptoms of LSS and the relationship between the said symptoms of LSS and magnitude of dural tube compression on MRI were analyzed in a cross-sectional and longitudinal fashion.

Results

1) The dural sac cross-sectional area (DCSA) decreased with age. 2) Severe dural tube compression had a strong influence on the presence of symptomatic LSS; however, 40%–70% of participants with severe dural tube compression did not show clinical symptoms of LSS. 3) At the 1-year follow-up, >50% of the LSS-positive participants in the initial year were reclassified as LSS negative, and 10% of the LSS-negative participants were reclassified as LSS positive. 4) The magnitude of the DCSA on MRI did not directly affect the presence of LSS at the 1-year follow-up.

Conclusion

LSS symptoms were changeable. Anatomical dural tube compression on MRI did not predict the presence of clinical LSS symptoms at the 1-year follow-up.

Is L5-S1 motion segment different from the rest? A radiographic kinematic assessment of 72 patients with chronic low back pain

PURPOSE

The relationship between biomechanical instability and degenerative changes in the lumbar spine in chronic low back pain (CLBP) patients remains controversial. The main objective of this retrospective radiographical study was to evaluate changes in kinematics at different lumbar levels (in particular the L5-S1 level) with progressive grades of disc degeneration and facet joint osteoarthritis in CLBP patients.

METHODS

Using standing neutral and dynamic flexion/extension (Fx/Ex) radiographs of the lumbar spine, in vivo segmental kinematics at L1-L2 through L5-S1 were evaluated in 72 consecutive CLBP patients. Disc degeneration was quantified using changes in signal intensity and central disc height on mid-sagittal T2-weighted magnetic resonance (MR) scans. Additionally, the presence or absence of facet joint osteoarthritis was noted on T2-weighted axial MR scans.

RESULTS

Disc degeneration and facet joint osteoarthritis occurred independent of each other at the L5-S1 level (p = 0.188), but an association was observed between the two at L4-L5 (p < 0.001) and L3-L4 (p < 0.05) levels. In the absence of facet joint osteoarthritis, the L5-S1 segment showed a greater range of motion (ROM) in Ex (3.3° ± 3.6°) and a smaller ROM in Fx (0.6° ± 4.2°) compared with the upper lumbar levels (p < 0.05), but the differences diminished in the presence of it. In the absence of facet joint osteoarthritis, no change in L5-S1 kinematics was observed with progressive disc degeneration, but in its presence, restabilisation of the L5-S1 segment was observed between mild and severe disc degeneration states.

CONCLUSION

The L5-S1 motion segment exhibited unique degenerative and kinematic characteristics compared with the upper lumbar motion segments. Disc degeneration and facet joint osteoarthritis occurred independent of each other at the L5-S1 level, but not at the other lumbar levels. Severe disc degeneration in the presence of facet joint osteoarthritis biomechanically restabilised the L5-S1 motion segment.

Advantages and disadvantages of posterolateral approach for percutaneous endoscopic lumbar discectomy

BACKGROUND

Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments for lumbar disc herniation (LDH), and has 3 different operative approaches. This study focused on the posterolateral approach (PLA) and investigated the appropriate operative indication.

METHODS

PLA was performed in 29 patients with foraminal and extraforaminal LDH. The height and width of the foramen, LDH type, and positional relationship between LDH and the foramen were radiologically evaluated. Foraminoplasty was also performed in 12 cases including those combined with intra-canal LDH or osseous foraminal stenosis. Pre- and postoperative status was evaluated using Numerical Rating Scale (NRS) scores.

RESULTS

Patient mean age was 56.8 years; there was single-level involvement at L3/4 (13 cases) and at L4/5 (13 cases). The mean pre- and postoperative NRS scores were 6.1 and 1.8, respectively. Early recurrence developed in a patient who was found to have local scoliosis at the corresponding vertebral level.

CONCLUSIONS

PLA can be safely used to treat foraminal and extraforaminal LDH with foraminal height ≥13 mm and foraminal width ≥7 mm. The procedure is effective for preserving the facet joint; however, we should carefully consider the indications when local scoliosis and/or instability are present.

Degeneration and Instability and the Relation to Patients' Function Late After Lumbar Disc Surgery: Data from a 12-Year Follow-Up

OBJECTIVE

To investigate the excess risk of degeneration and segmental instability in operated segments late after lumbar disc surgery in patients with presurgically stable segments, and whether local pathological findings relate to patients' back health.

DESIGN

This retrospective analysis reports on 69 patients 12 years after first-time, uncomplicated lumbar disc surgery. Two independent radiologists evaluated the patients' lumbar functional x-rays; the Back Pain Rating Score (LBP-RS) assessed back-specific function.

RESULTS

At 12 years after lumbar disc surgery, degenerative changes as well as segmental instability occurred significantly more frequently in the operated than nonoperated lumbar segments, but there was no association between increased degeneration and segmental instability rates. The risk for acquiring segmental instability was significantly associated with surgery (odds ratio, 6.5; 95% confidence interval, 1.5-28.8). Prevalence of segmental instabilities was associated with better LBP-RS scores. Analyses of LBP-RS subscores revealed a clear association of segmental instability with physical function, but not with pain or activities of daily living.

CONCLUSIONS

Lumbar disc surgery seems to be associated with an increased risk of degeneration and segmental instability in the long term. This structural impairment, however, seems functionally well compensated and does not seem to be a relevant causal factor for a chronic back pain syndrome.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES:: Upon completion of this article, the reader should be able to: (1) Describe the impact of lumbar disc surgery on segmental instability and degenerative changes; (2) Recognize the lack of association between degenerative changes and segmental instability after lumbar disc surgery; and (3) State the value of lumbar spinal functional tests in the evaluation of patients after lumbar disc surgery.

LEVEL

Advanced ACCREDITATION:: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Guideline summary review: An evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spondylolisthesis

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Degenerative Lumbar Spondylolisthesis features evidence-based recommendations for diagnosing and treating degenerative lumbar spondylolisthesis. The guideline updates the 2008 guideline on this topic and is intended to reflect contemporary treatment concepts for symptomatic degenerative lumbar spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of May 2013. The NASS guideline on this topic is the only guideline on degenerative lumbar spondylolisthesis included in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse (NGC).

PURPOSE

The purpose of this guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for patients with degenerative lumbar spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

A systematic review of clinical studies relevant to degenerative spondylolisthesis was carried out.

METHODS

This NASS spondyolisthesis guideline is the product of the Degenerative Lumbar Spondylolisthesis Work Group of NASS' Evidence-Based Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members used the NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Degenerative Lumbar Spondylolisthesis guideline was accepted into the NGC and will be updated approximately every 5 years.

RESULTS

Twenty-seven clinical questions were addressed in this guideline update, including 15 clinical questions from the original guideline and 12 new clinical questions. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence. Twenty-one new or updated recommendations or consensus statements were issued and 13 recommendations or consensus statements were maintained from the original guideline.

CONCLUSIONS

The clinical guideline was created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with degenerative lumbar spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flow chart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/Pages/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.

Sensitivity of magnetic resonance imaging in the diagnosis of mobile and nonmobile L4-L5 degenerative spondylolisthesis

BACKGROUND CONTEXT

Lumbar degenerative spondylolisthesis (LDS) is often diagnosed by conventional supine magnetic resonance imaging (MRI). Numerous studies have shown, however, that the degree of spondylolisthesis can be reduced or disappears when the patient is supine as compared with standing lateral and flexion-extension (SLFE) radiographs.

PURPOSE

To compare the sensitivity of supine MRI with SLFE radiographs in patients with L4-L5 LDS.

STUDY DESIGN

A retrospective imaging study.

PATIENT SAMPLE

Included patients diagnosed with L4-L5 LDS with both SLFE films and supine MRI.

METHODS

Lumbar degenerative spondylolisthesis was defined radiographically as a slip greater than 4.5 mm. Mobile LDS was defined as a difference of greater than 3% in slip percentage between lateral radiographs and sagittal MRIs. Additional measurements included L4-L5 facet effusion diameter on axial MRIs. Measurements were performed by two independent examiners. The kappa coefficient was used to assess the interobserver agreement.

RESULTS

Of 103 patients assessed, 68% were women and the average age was 66 years. Lumbar degenerative spondylolisthesis was seen on 101 (98%) lateral films and 80 (78%) MRIs. Average slip was 10.0 mm for lateral standing radiographs and 6.6 mm on MRI (p<.0001). Fifty (48%) patients were identified with mobile LDS. The positive predictive value of facet joint effusion for mobile LDS increased from 52% for effusions greater than 1 mm to 100% for effusions greater than 3.5 mm.

CONCLUSIONS

This study found that MRI had a sensitivity of 78% for detecting L4-L5 LDS compared with 98% for lateral standing films. We also identified facet effusion size as a marker to predict mobile LDS. These findings suggest that, particularly in the setting of facet effusions, the complete workup of patients in whom LDS is possible should include standing radiographs.

Development of a novel radiographic measure of lumbar instability and validation using the facet fluid sign

BACKGROUND

Lumbar spinal instability is frequently referenced in clinical practice and the scientific literature despite the lack of a standard definition or validated radiographic test. The Quantitative Stability Index (QSI) is being developed as a novel objective test for sagittal plane lumbar instability. The QSI is calculated using lumbar flexion-extension radiographs. The goal of the current study was to use the facet fluid sign on MRI as the "gold standard" and determine if the QSI is significantly different in the presence of the fluid sign.

METHODS

Sixty-two paired preoperative MRI and flexion-extension exams were obtained from a large FDA IDE study. The MRI exams were assessed for the presence of a facet fluid sign, and the QSI was calculated from sagittal plane intervertebral rotation and translation measurements. The QSI is based on the translation per degree of rotation (TPDR) and is calculated as a Z-score. A QSI > 2 indicates that the TPDR is > 2 std dev above the mean for an asymptomatic and radiographically normal population. The reproducibility of the QSI was also tested.

RESULTS

The mean difference between trained observers in the measured QSI was between -0.28 and 0.36. The average QSI was significantly (P = 0.047, one-way analysis of variance) higher at levels with a definite fluid sign (2.3±3.2 versus 0.60±2.4).

CONCLUSIONS

Although imperfect, the facet fluid sign observed may be the best currently available test for lumbar spine instability. Using the facet fluid sign as the "gold standard" the current study documents that the QSI can be expected to be significantly higher in the presence of the facet fluid sign. This supports that QSI might be used to test for sagittal plane lumbar instability.

CLINICAL RELEVANCE

A validated, objective and practical test for spinal instability would facilitate research to understand the importance of instability in diagnosis and treatment of low-back related disorders.

Risk Factors For the Development of a Mobile Degenerative Spondylolisthesis at L4-L5

OBJECTIVE

The purpose of this study was to identify factors that may be important in determining whether a degenerative spondylolisthesis at L4-L5 is mobile.

SUMMARY OF BACKGROUND DATA

Degenerative scoliosis is a common condition among middle-aged and elderly adults. Sacropelvic morphology and orientation modulate the geometry of the lumbar spine and, consequently, the mechanical stresses at the lumbo-sacral junction. To date, no in vivo data exist to describe the relationship between these pelvic parameters and their association with a mobile spondylolisthesis.

METHOD

Sixty consecutive patients with a degenerative spondylolisthesis (DS) at L4-L5 with adequate imaging were identified. Patient groups were defined on the basis of whether the DS was mobile (Group A) or nonmobile (Group B) when comparing the upright plain lumbar radiograph to the supine magnetic resonance imaging (MRI). We assessed the grade of slip, lumbar lordosis, pelvic parameters, and facet characteristics (angles, tropism, presents of effusion, degenerative score-cartilage and sclerosis values) as well as disc degenerative score (Pfirrmann) at L4-L5.

RESULTS

There were 40 patients in Group A and 20 in Group B. No significant differences were found between groups for pelvic incidence (p = .409), pelvic tilt (p = .476), sacral slope (p = .785), lumbar lordosis (p = .695), degree of facet tropism (p = .38), and magnitude of the facet effusions (p = .01). Facet angle differences between groups approached significance (p = .058). Significant differences between groups were found in cartilage degenerative score (p = .01), facet sclerosis grade (p = .01), and disc degenerative score (p < .0001). In Group A, 10 of 40 (25%) reduced fully and were not apparent on the supine MRI.

CONCLUSIONS

Sagittal pelvic parameters do not play a significant role in differentiating between mobile and nonmobile DS at L4-L5. However, DS does appear to be associated with more sagittally orientated facets, higher Pfirrmann grade, and higher facet cartilage and sclerosis degenerative scores.

A review of the value of MRI signs in low back pain

Low back pain is a common symptom that can lead to disability and major socio-professional repercussions. Despite advances in imaging, the etiology of the pain often remains unknown. Morphological changes related to normal ageing of the disc appear on MR imaging without any symptoms. The potential impact of changes seen on imaging, especially MRI, also warrants discussion. The purpose of this work is to review the state-of-the-art of this subject, underlining relevant key features for routine radiological practice. We will first discuss anterior and posterior segments of the spine with a focus on anatomical, physiopathological and semiological findings. Secondly we will discuss the diagnostic value of each sign.

The significance of facet joint cross-sectional area on magnetic resonance imaging in relationship to cervical degenerative spondylolisthesis

BACKGROUND CONTEXT

Characteristic changes of the facet joints, including synovial cysts, facet joint hypertrophy, and facet joint effusions, on magnetic resonance imaging (MRI) and computed tomography have been associated with lumbar degenerative spondylolisthesis. The cervical facets have not been examined for associations with cervical degenerative spondylolisthesis similar to those seen in the lumbar spine.

PURPOSE

To define abnormalities of the facet joints seen on supine MRI that correlate with cervical spondylolisthesis seen on upright radiographs.

STUDY DESIGN

Retrospective radiographic review of consecutive patients with a universally applied standard.

PATIENT SAMPLE

A total of 204 consecutive patients from a single institution, with both an MRI and upright radiographs, were reviewed.

OUTCOME MEASURES

Sagittal plane displacement on upright lateral radiographs was compared with MRI. The total area of the facet joint and the amount of facet joint asymmetry were measured on an axial MRI.

METHODS

The data were analyzed to determine a significant association between the cervical degenerative spondylolisthesis and the following: facet joint asymmetry, increased total area of the facet joint, and age.

RESULTS

Degenerative spondylolisthesis was seen in 26 patients at C3-C4 and in 27 patients at C4-C5. Upright radiographs identified significantly more degenerative spondylolisthesis than MRIs at levels C3-C4 and C4-C5, 26 versus 6 (p<.001) at C3-C4 and 27 versus 11 (p<.001) at C4-C5. Patients with degenerative spondylolisthesis were more likely to be older, have a larger total facet area, and more facet asymmetry at C3-C4 and C4-C5 (p<.05).

CONCLUSIONS

Supine MRIs underestimate sagittal displacement compared with upright lateral radiographs. Asymmetric facet hypertrophy at C3-C4 and C4-C5 is associated with degenerative spondylolisthesis on upright lateral films even in the absence of anterolisthesis on supine MRIs.

Current classification systems for adult degenerative scoliosis

At present, a big effort of the scientific community has been directed toward a more proper and standardized approach to the patients affected by degenerative scoliosis, and recent attention has turned toward the development of classification schemes. A literature analysis highlighted several classification schemes developed for degenerative scoliosis patients: the Simmons classification system, the Aebi system, the Faldini working classification system, the Schwab system, and the Scoliosis Research Society system. Aim of the current manuscript is to scrutinize the available literature in order to provide a comprehensive overview of these current classification schemes for adult scoliosis, by describing and commenting clinical development, limits and potential of their application together with their implications for surgical planning.

The correlation between microvessel pathological changes of the endplate and degeneration of the intervertebral disc in diabetic rats

In this study, the pathological microvessel changes to the endplate and the degeneration of the intervertebral disc of diabetic rats were examined in order to identify the possible mechanism by which diabetes mellitus (DM) induces degeneration of the intervertebral disc. A total of 30 Sprague-Dawley rats were randomly divided into two groups. DM was induced in one of the groups by streptozotocin (STZ) administration. The rats were sacrificed 4, 8 and 12 weeks later. Five rats from each group were sacrificed at each time interval and lumbar disc and endplate tissue were obtained from each rat. The histological changes, collagen expression, microvessel density (MVD) and apoptosis of the disc were investigated by different methods. The expression of collagen I in the diabetic DM group was higher compared to the control group at the three time points (P<0.01), in contrast to the expression of collagen II. The factor VIII-related antigen (FVIII RAg) was expressed in the control and DM groups, while its expression was relatively low in the DM group. The MVD of the DM group was smaller compared to that of the control group at the three time points (P<0.01). The apoptotic index (AI) in the diabetic group was significantly higher compared to that of the control group at the three time points (P<0.01). A negative correlation was observed between the MVD of the endplates and the notochordal cell AI in the two groups. Compared to the control group, the endplate MVD decreased and the cavity became smaller or disappeared in the diabetic rats. In conclusion, there was a negative correlation between MVD and degenerative changes of the intervertebral disc in diabetic rats.