MRI findings of lumbar spine instability in degenerative spondylolisthesis

Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial

OBJECTIVE

To assess whether decompression alone is non-inferior to decompression with instrumented fusion five years after primary surgery in patients with degenerative lumbar spondylolisthesis.

DESIGN

Five year follow-up of a randomised, multicentre, non-inferiority trial (Nordsten-DS).

SETTING

16 public orthopaedic and neurosurgical clinics in Norway.

PARTICIPANTS

Patients aged 18-80 years with symptomatic lumbar spinal stenosis and a spondylolisthesis of 3 mm or more at the stenotic level.

INTERVENTIONS

Decompression surgery alone and decompression with additional instrumented fusion (1:1).

MAIN OUTCOME MEASURES

The primary outcome was a 30% or more reduction in Oswestry disability index from baseline to five year follow-up. The predefined non-inferiority margin was a -15 percentage point difference in the proportion of patients who met the primary outcome. Secondary outcomes included the mean change in Oswestry disability index, Zurich claudication questionnaire, numeric rating scale for leg and back pain, and EuroQol Group 5-Dimension (EQ-5D-3L) questionnaire.

RESULTS

From 12 February 2014 to 18 December 2017, 267 participants were randomly assigned to decompression alone (n=134) and decompression with instrumented fusion (n=133). Of these, 230 (88%) responded to the five year questionnaire: 121 in the decompression group and 109 in the fusion group. Mean age at baseline was 66.2 years (SD 7.6), and 69% were women. In the modified intention-to-treat analysis with multiple imputation of missing data, 84 (63%) of 133 people in the decompression alone group and 81 (63%) of 129 people in the fusion group had a at least a 30% reduction in Oswestry disability index, a difference of 0.4 percentage points. (95% confidence interval (CI) -11.2 to 11.9). The respective results of the per protocol analysis were 65 (65%) of 100 in the decompression alone group and 59 (66%) of 89 in the fusion group, a difference of -1.3 percentage points (95% CI -14.5 to 12.2). Both 95% CIs were higher than the predefined non-inferiority margin of -15%. The mean change in Oswestry disability index from baseline to five years was -17.8 in both groups (mean difference 0.02 (95% CI -3.8 to 3.9)). Results of the other secondary outcomes were in the same direction as the primary outcome. From two to five year follow-up, a new lumbar operation occurred in six (5%) of 123 people in the decompression group and 11 (10%) of 113 people in the fusion group, with a total from baseline to five years of 21 (16%) of 129 people and 23 (18%) of 125, respectively.

CONCLUSIONS

In participants with degenerative spondylolisthesis, decompression alone was non-inferior to decompression with instrumented fusion five years after primary surgery. Proportions of subsequent surgeries at the index level or an adjacent lumbar level were no different between the groups.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02051374.

Can magnetic resonance imaging findings effectively diagnose the instability observed on radiographs in patients with degenerative lumbar spinal stenosis?

BACKGROUND

Degenerative lumbar spinal stenosis (LSS) is a common condition that involves the narrowing of the spinal canal. Diagnosing instability traditionally requires standing lateral radiographs to detect dynamic translation, but there is debate about relying solely on radiographs due to challenges like patient discomfort and radiation exposure. This study aimed to evaluate if Magnetic Resonance Imaging (MRI) findings could effectively diagnose instability observed on radiographs.

METHODS

We reviewed 478 consecutive patients with degenerative LSS who had surgery at our institution. Instability was defined as a sagittal translation exceeding 3 mm on standing lateral radiographs in both extension and flexion. Patients were divided into stable (those with < 3 mm translation) and unstable groups (those with > 3 mm translation). The study assessed potential variables for instability, including MRI findings like facet joint effusion, facet joint angle, disk height index, intradiscal vacuum presence, endplate sclerosis, ligamentum flavum hypertrophy, and multifidus muscle fatty degeneration, comparing these factors between the two groups.

RESULTS

A total of 478 consecutive patients diagnosed with degenerative Lumbar Spinal Stenosis (LSS) were included. The average age of the patients was 66.32 years, with 43.3% being male. Approximately 27.6% of the cases exhibited signs of instability on the standing lateral radiograph during extension and flexion. The multivariate analysis using binary logistic regression revealed that facet joint effusion (odds ratio [OR] 2.73; 95% confidence interval [CI] 1.27-3.94; P = 0.002), disk height index (OR 2.22; 95% CI 1.68-3.35; P = 0.009), and the presence of the Vacuum sign (OR 1.77; 95% CI 1.32-2.84; P = 0.021) were identified as factors associated with instability.

CONCLUSIONS

Our findings showed thata higher facet joint effusion, the presence of Vacuum sign, and a greater Disk Height Index were associated with the presence of instability on the standing lateral radiograph in extension and flexion in patients with degenerative LSS.

The Relationship Between MRI Findings of Posterior Ligamentous Complex and Lumbar Instability in Degenerative Spondylolisthesis

Background

To determine the factors in posterior ligamentous complex indicating lumbar instability in patients diagnosed with degenerative spondylolisthesis on conventional magnetic resonance imaging (MRI).

Methods

We retrospectively analyzed patients who underwent PLIF surgery for degenerative spondylolisthesis at our institution between 2018 and 2020 and who had complete eligible preoperative imaging data for review and study, including lumbar MRI and anteroposterior and flexion-extension radiographs.

Results

Fifty-three patients were confirmed to have lumbar instability (Unstable Group, 44%), while sixty-seven patients (Stable Group, 56%) did not have instability on radiographs. The patients in the stable group had more advanced status of the degeneration of intervertebral disc than in the unstable group (p<0.05). The degeneration of supraspinous ligament (SSL) was more severe in the unstable group (p<0.05). Compared with the patients with rotatory instability, advanced degeneration of interspinous ligament (ISL) and SSL was observed in patients with translatory instability (p<0.05). However, there was no significant difference with regard to the height of the spinous process and the interspinous distance in patients with or without instability.

Conclusion

This MRI analysis showed that abnormal segmental motion is closely associated with the pathological characteristics of supraspinal ligament. Advanced degeneration of SSL in patients with degenerative spondylolisthesis should raise the suspicion for lumbar instability and additional evaluations. The status of ISL and ligamentum flavum (LF) may not be helpful for the diagnosis of lumbar instability. Functional radiographs combined with MRI may provide valuable information when diagnosing lumbar instability in patients with mechanical back pain.

Decision-making Algorithm for the Surgical Treatment of Degenerative Lumbar Spondylolisthesis of L4/L5

STUDY DESIGN

A retrospective analysis of prospectively collected data.

OBJECTIVE

To report the decision-making process for decompression alone (DA) and decompression and fusion (DF) at a tertiary orthopedic center and compare the operative outcomes between both groups.

BACKGROUND

Controversy exists around the optimal operative treatment for DLS, either with DF or DA. Although previous studies tried to establish specific indications, clinical decision-making algorithms are needed.

MATERIALS AND METHODS

Patients undergoing spinal surgery for DLS at L4/5 were retrospectively analyzed. A survey of spine surgeons was performed to identify factors influencing surgical decision-making, and their association with the surgical procedure was tested in the clinical data set. We then developed a clinical score based on the statistical analysis and survey results. The predictive capability of the score was tested in the clinical data set with a receiver operating characteristic (ROC) analysis. To evaluate the clinical outcome, two years follow-up postoperative Oswestry Disability Index (ODI), postoperative low back pain (LBP) (Numeric Analog Scale), and patient satisfaction were compared between the DF and DA groups.

RESULTS

A total of 124 patients were included in the analysis; 66 received DF (53.2%) and 58 DA (46.8%). Both groups showed no significant differences in postoperative ODI, LBP, or satisfaction. The degree of spondylolisthesis, facet joint diastasis and effusion, sagittal disbalance, and severity of LBP were identified as the most important factors for deciding on DA or DF. The area under the curve of the decision-making score was 0.84. At a cutoff of three points indicating DF, the accuracy was 80.6%.

CONCLUSIONS

The two-year follow-up data showed that both groups showed similar improvement in ODI after both procedures, validating the respective decision. The developed score shows excellent predictive capabilities for the decision processes of different spine surgeons at a single tertiary center and highlights relevant clinical and radiographic parameters. Further studies are needed to assess the external applicability of these findings.

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.

Factors affecting successful immediate indirect decompression in oblique lateral interbody fusion in lumbar spinal stenosis patients

Background

Oblique lumbar interbody fusion (OLIF) offers indirect decompression of stenotic lesions of the spinal canal and foramen through immediate disc height restoration. Only a few studies have reported the effect of cage position and associated intraoperatively modifiable factors for successful immediate indirect decompression following OLIF surgery. This study aimed to investigate the intraoperatively modifiable factors for successful radiological outcomes of OLIF.

Methods

This study included 46 patients with 80 surgical levels who underwent OLIF without direct posterior decompression. Preoperative and postoperative radiological parameters were evaluated and intraoperatively modifiable radiologic parameters for successful immediate radiologic decompression on magnetic resonance image (MRI) were determined. Radiologic parameters were preoperative and postoperative radiological parameters including anterior disc height (ADH), posterior disc height (PDH) lumbar lordotic angle (LLA), segmental lordotic angle (SLA), foraminal height (FH), cage position, cross-sectional area (CSA) of the thecal sac, cross-sectional foraminal area (CSF), facet distance (FD).

Results

All radiologic outcomes significantly improved. Comparing preoperative and postoperative values, mean CSA increased from 99.63±40.21 mm2 to 125.02±45.90 mm2 (p<.0001), and mean left CSF increased from 44.54±12.90 mm2 to 69.91±10.80 mm2 (p<.0001). FD also increased from 1.40±0.44 to 1.92±0.71 mm (p<.0001). FH increased from 16.31±3.3 to 18.84±3.47 mm (p<.0001). ADH and PDH also significantly increased (p<.0001). Immediate postoperative CSF and FH improvement rate (%) were significantly correlated with posterior disc height restoration rate (%) (p=.0443, and p=.0234, respectively). In addition, the patients with a cage positioned in the middle of the vertebral body experienced a greater FH improvement rate (%) compared to the patients with a cage positioned anteriorly. Finally, Visual analogue scale (VAS) for leg pain was improved immediately.

Conclusions

OLIF provided satisfactory immediate indirect decompression in central and foraminal spinal stenosis. Moreover, intraoperative surgical technique for successful radiologic CSF and FH improvement included restoration of the PDH and placement of the cage in the middle.

Minimally invasive fenestration for decompression of C2-C3 spinal stenosis

Conventional techniques in neurosurgery such as laminectomy have been extensively displaced by minimally invasive types, owing to the character of complexity of cervical spinal region. Spinal canal stenosis at C2-C3 level is documented in the literature with the majority being caused by intervertebral disc herniations.This case reports a patient who presented with classical myelopathy symptoms and significant thickening of ligamentum flavum, while minimal spondylosis was detected at C2-C3 level. The decompression was performed from posterior approach and limited to the removal of ligamentum flavum with minimal resection of adjacent laminae, no fixation and no disc evacuation. After surgery, there was a significant improvement with preserved spinal stability.Although the anterior approach is more common for cervical spine, universal access site has not been defined in literature. We suggest that minimal decompression produces desirable effects with no need for fusion and preserving adequate stability of spinal complex.

Lumbar Facet Joint Fluid: A Reliable Sign of Lumbar Instability

Lumbar degenerative spondylolisthesis (LDS) is a prevalent condition among the elderly population. Magnetic resonance imaging (MRI) is often the first investigative modality if indicated clinically. However, the standard supine position used during an MRI may fail to detect dynamic instability. In such cases, the presence of facet joint fluid is a reliable sign, and further investigation, such as stress radiographs, should be conducted to confirm dynamic instability. Here, we present a typical case demonstrating the importance of this finding. A patient presented with neurological claudication, and an MRI was initially unremarkable except for the presence of lumbar facet joint fluid. This finding prompted us to conduct stress radiographs, which eventually confirmed dynamic instability.

Utility of a fulcrum for positioning support during flexion-extension radiographs for assessment of lumbar instability in patients with degenerative lumbar spondylolisthesis

OBJECTIVE

The authors investigated a new standardized technique for evaluating lumbar stability in lumbar lateral flexion-extension (LFE) radiographs. For patients with lumbar spondylolisthesis, a three-part fulcrum with a support platform that included a semiarc leaning tool with armrests, a lifting platform for height adjustment, and a base for stability were used. Standard functional radiographs were used for comparison to determine whether adequate flexion-extension was acquired through use of the fulcrum method.

METHODS

A total of 67 consecutive patients diagnosed with L4-5 degenerative lumbar spondylolisthesis were enrolled in the study. The authors analyzed LFE radiographs taken with the patient supported by a fulcrum (LFEF) and without a fulcrum. Sagittal translation (ST), segmental angulation (SA), posterior opening (PO), change in lumbar lordosis (CLL), and lumbar instability (LI) were measured for comparison using functional radiographs.

RESULTS

The average value of SA was 5.76° ± 3.72° in LFE and 9.96° ± 4.00° in LFEF radiographs, with a significant difference between them (p < 0.05). ST and PO were also significantly greater in LFEF than in LFE. The detection rate of instability was 10.4% in LFE and 31.3% in LFEF, and the difference was significant. The CLL was 27.31° ± 11.96° in LFE and 37.07° ± 12.963.16° in LFEF, with a significant difference between these values (p < 0.05).

CONCLUSIONS

Compared with traditional LFE radiographs, the LFEF radiographs significantly improved the detection rate of LI. In addition, this method may reduce patient discomfort during the process of obtaining radiographs.

The efficacy of quantitative magnetic resonance imaging in the diagnosis of unstable L4/L5 degenerative spondylolisthesis

Lumbar degenerative spondylolisthesis (LDS) is a common degenerative disease that particularly affects the elderly. LDS can occur in any segment of the spine but is most commonly found in the L4/L5 segment. In the present study, a quantitative study of lumbar MRI measurements was conducted to identify predisposing factors indicative of spinal instability in patients with L4/L5 LDS. In total, 81 patients [58 patients in the stable group (SG) and 23 patients in the unstable group (UG)] who were diagnosed with L4/L5 LDS on X-ray and MRI between January 2021 and January 2022 were included in this study. Disk height, disk signal intensity on T1-weighted (T1W) and T2-weighted (T2W) images, facet joint fluid thickness, and ligamentum flavum thickness were measured on MRI, and the differences in these parameters between the two groups were evaluated. The receiver operating characteristic curve was generated, and the area under the curve (AUC), cut-off value, sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) were calculated for parameters found to be significantly different between the two groups. The facet joint fluid was significantly thicker in the UG than in the SG (P<0.01), and a cut-off value of 1.45 mm was found to have an AUC of 0.77 and an SE, SP, PPV, and NPV of 73.9, 67.2, 69.3, and 69.77%, respectively. No significant differences were identified between the two groups for mean disk height, ligamentum flavum thickness, or disk signal intensity on T1W or T2W images. The facet joint fluid thickness on axial T2W images may represent a useful predictor of spinal instability in patients with LDS. Therefore, spinal instability should be assessed, and additional evaluation methods, such as standing lateral flexion-extension radiographs, should be performed when facet fluid is detected on lumbar MRI.

Treatment of restenosis after lumbar decompression surgery: decompression versus decompression and fusion

OBJECTIVE

The aim of this study was to compare perioperative complications and postoperative outcomes between patients with lumbar recurrent stenosis without lumbar instability and radiculopathy who underwent decompression surgery and those who underwent decompression with fusion surgery.

METHODS

For this retrospective study, the authors identified 2606 consecutive patients who underwent posterior surgery for lumbar spinal canal stenosis at eight affiliated hospitals between April 2017 and June 2019. Among these patients, those with a history of prior decompression surgery and central canal restenosis with cauda equina syndrome were included in the study. Those patients with instability or radiculopathy were excluded. The patients were divided between the decompression group and decompression with fusion group. The demographic characteristics, numerical rating scale score for low-back pain, incidence rates of lower-extremity pain and lower-extremity numbness, Oswestry Disability Index score, 3-level EQ-5D score, and patient satisfaction rate were compared between the two groups using the Fisher's exact probability test for nominal variables and the Student t-test for continuous variables, with p < 0.05 as the level of statistical significance.

RESULTS

Forty-six patients met the inclusion criteria (35 males and 11 females; 19 patients underwent decompression and 27 decompression and fusion; mean ± SD age 72.5 ± 8.8 years; mean ± SD follow-up 18.8 ± 6.0 months). Demographic data and perioperative complication rates were similar. The percentages of patients who achieved the minimal clinically important differences for patient-reported outcomes or satisfaction rate at 1 year were similar.

CONCLUSIONS

Among patients with central canal stenosis who underwent revision, the short-term outcomes of the patients who underwent decompression were comparable to those of the patients who underwent decompression and fusion. Decompression surgery may be effective for patients without instability or radiculopathy.

Impact of Concomitant Spinal Canal Stenosis on Clinical Presentation of Adult Onset Degenerative Lumbar Spondylolisthesis: A Study Combining Clinical and Imaging Spectrum

Aim Degenerative lumbar spondylolisthesis (DSL) is one of the reasons behind adult-onset backache due to degenerative spinal pathology. Clinical manifestations of this can range from asymptomatic patients to widely variable clinical signs and symptoms. Spinal canal stenosis (SCS) is the most common associated degenerative condition in the MRI of DSL. Moreover, other associated degenerative conditions may contribute significantly towards the clinical presentation. We have tried to assess the impact of SCS on the clinical symptomatology and presentation of the DSL by correlating the clinical and imaging findings. Methods This single-center prospective observational study has analysed 48 patients who were symptomatic due to DSL. The data was collected over a period of 18 months from January 2015 to June 2016 by screening through the adult patients presenting at the orthopaedic or spinal clinics with features suggestive of degenerative lumbar spine disease. Particular inclusion and exclusion criteria were developed as a screening tool and selected patients underwent imaging investigations. Patients had lumbar spine radiographs, both standing and flexion-extension view, and MRI of the lumbar spine. The presenting clinical features were documented. Their clinical and neurological assessment was done thoroughly by two qualified clinicians independently. Results The study population included 29 female (60.5%) and 19 male (39.5%) patients. The mean age of the study population was 49.5 years (SD 9.2 years). As per the radiological diagnostic criteria, 28 patients (58.3%) had features of SCS together with DSL and the rest of the 20 patients (41.7%) had DSL without SCS. Axial back pain and claudication had a statistically significant association with imaging findings. Similarly, patients with associated canal stenosis had statistically significant sensory and motor deficits, altered deep tendon reflexes. Facet joint angle more than 45 degrees at the level of the slip had a higher incidence of indicative presenting symptoms. However, this was not statistically proven. Conclusion DSL is a heterogeneous condition with the simultaneous presence of different degenerative processes in the lumbar spine at various stages. Hence, clinical presentations are widely variable. The concomitant presence of SCS significantly influences the clinical symptomatology with correlation to the MRI findings. Therefore, a judicious weighing of the clinical and imaging findings is crucial for prudent management planning for cases of DSL.

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.

Improvement of Lower Back Pain in Lumbar Spinal Stenosis After Decompression Surgery and Factors That Predict Residual Lower Back Pain

STUDY DESIGN

Retrospective observational study.

OBJECTIVES

There is no consensus to predict improvement of lower back pain (LBP) in lumbar spinal stenosis after decompression surgery. The aim of this study was to evaluate the improvement of LBP and analyze the preoperative predicting factors for residual LBP.

METHODS

We retrospectively reviewed 119 patients who underwent lumbar decompression surgery without fusion and had a minimum follow-up of 1 year. LBP was evaluated using the numerical rating scale (NRS), Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) LBP score, and Roland-Morris Disability Questionnaire (RMDQ). All patients were divided into LBP improved group (group I) and LBP residual group (group R) according to the NRS score. Radiographic images were examined preoperatively and at the final follow-up. We evaluated spinopelvic radiological parameters and analyzed the differences between group I and group R.

RESULTS

LBP was significantly improved after decompression surgery (LBP NRS, 5.7 vs 2.6, P < .001; JOABPEQ LBP score, 41.3 vs 79.6, P < .001; RMDQ, 10.3 vs 3.6, P < .001). Of 119 patients, 94 patients were allocated to group I and 25 was allocated to group R. There was significant difference in preoperative thoracolumbar kyphosis between group I and group R.

CONCLUSIONS

Most cases of LBP in lumbar spinal stenosis were improved after decompression surgery without fusion. Preoperative thoracolumbar kyphosis predicted residual LBP after decompression surgery.

Modified Facet Joint Fusion for Lumbar Degenerative Disease: Case Series of a Fusion Technique, Clinical Outcomes, and Fusion Rate in 491 Patients

BACKGROUND

Controversy still exists regarding the optimal fusion technique for the treatment of unstable lumbar spondylolisthesis.

OBJECTIVE

To evaluate the safety and efficacy of modified facet joint fusion (MFF).

METHODS

A total of 491 patients with unstable lumbar spondylolisthesis who underwent MFF were retrospectively reviewed. Computed tomography was used to evaluate the fusion rate of MFF at 6- and 12-mo follow-up postoperatively. Clinical outcomes included visual analog scale pain scores for low back pain (VAS-LBP) and leg pain (VAS-LP), Japanese Orthopedic Association scores (JOA), and Oswestry Disability Index (ODI), all of which were obtained preoperatively and postoperatively at 1-, 3-, 6-, and 12-mo follow-up times. The clinical outcomes were determined to be excellent, good, fair, or poor according to the MacNab classification at the last follow-up time.

RESULTS

Of the 491 patients, the fusion rates at the 6-mo and 1-yr follow-up were 56.8% and 96.1%, respectively. Between baseline and 1-yr follow-up time, VAS-LP and VAS-LBP improved from 5.6 ± 0.9 to 0.4 ± 0.5 and 5.1 ± 1.2 to 1.5 ± 0.9, respectively (P < .001). JOA improved from 9.0 ± 2.0 to 27.7 ± 1.0, and ODI decreased from 64.0 ± 2.0 to 19 ± 1.0 (P < .001). At the final evaluation, 93.6% patients showed excellent or good results, and 3.2% showed fair results. There were no MFF technique-related complications.

CONCLUSION

MFF technique achieved satisfactory clinical outcomes and fusion rate and appears to be a promising alternative fusion technique for the treatment of unstable lumbar spondylolisthesis.

Clinical outcomes with endoscopic resection of lumbar extradural cysts

Background

Lumbar extradural cysts may be associated with sciatica-type back and leg pain. The symptoms of clinical pain syndrome from synovial cysts are sometimes difficult to differentiate from those of lumbar disc herniation or spinal canal stenosis and may be identified to be a pain source when visualized endoscopically. The authors analyzed the clinical outcomes with their endoscopic resection to better establish clinical indications and prognosticators of favorable results.

Methods

Two-year Macnab outcomes, VAS scores, and complications were analyzed in a series of 48 patients treated with the endoscopic removal of extradural cyst encountered during routine transforaminal and interlaminar decompression for foraminal and lateral recess stenosis causing lumbar radiculopathy.

Results

There were 26 female and 22 male patients. The extradural cysts were most commonly encountered at L4/5 level in 26 patients (72.2%) followed by the L5/S1 level in 8 patients (22.2%), and in 2 patients (5.6%) at the L3/4 level, respectively. One patient underwent T9/10 decompression. At minimum 2-year follow-up, all patients were improved. Excellent results according to the Macnab criteria were obtained in 19/48 (39.6%) patients, good in 18/48 (37.5%), and fair in 11/48 (22.9%), respectively. The average preoperative VAS score for leg pain was 8.06±1.57 and reduced at a statistically significant level (P<0.000) postoperatively to 1.92±1.49, and 1.77±1.32 at final follow-up, respectively. The percentage of patients with unlimited walking endurance had improved at a statistically significant level (P<0.0001) from 33.3% preoperatively (16/48) to 81.3% (39/48) postoperatively. One patient had a recurrent disc herniation, and another patient did not improve. Two patients underwent fusion during the follow-up period. Patients with Fair outcomes had a statistically significant association (P<0.001) with facet instability as suggested by axial T2-weighted magnetic resonance imaging (MRI) findings of thickened ligamentum flavum, facet joint hypertrophy, and bright white fluid-filled joint gap of >2 mm.

Conclusions

Endoscopic resection of extradural spinal cysts during routine decompression for symptomatic foraminal and lateral recess stenosis is feasible with favorable clinical outcomes in the majority of patients. Fair outcomes were associated with advanced instability of the involved lumbar facet joint complex.

Decompression alone versus decompression with instrumental fusion the NORDSTEN degenerative spondylolisthesis trial (NORDSTEN-DS); study protocol for a randomized controlled trial

BACKGROUND

Fusion in addition to decompression has become the standard treatment for lumbar spinal stenosis with degenerative spondylolisthesis (DS). The evidence for performing fusion among these patients is conflicting and there is a need for further investigation through studies of high quality. The present protocol describes an ongoing study with the primary aim of comparing the outcome between decompression alone and decompression with instrumented fusion. The secondary aim is to investigate whether predictors can be used to choose the best treatment for an individual. The trial, named the NORDSTEN-DS trial, is one of three studies in the Norwegian Degenerative Spinal Stenosis (NORDSTEN) study.

METHODS

The NORDSTEN-DS trial is a block-randomized, controlled, multicenter, non-inferiority study with two parallel groups. The surgeons at the 15 participating hospitals decide whether a patient is eligible or not according to the inclusion and exclusion criteria. Participating patients are randomized to either a midline preserving decompression or a decompression followed by an instrumental fusion. Primary endpoint is the percentage of patients with an improvement in Oswestry Disability Index version 2.0 of more than 30% from baseline to 2-year follow-up. Secondary outcome measurements are the Zürich Claudication Questionnaire, Numeric Rating Scale for back and leg pain, Euroqol 5 dimensions questionnaire, Global perceived effect scale, complications and several radiological parameters. Analysis and interpretation of results will also be conducted after 5 and 10 years.

CONCLUSION

The NORDSTEN/DS trial has the potential to provide Level 1 evidence of whether decompression alone should be advocated as the preferred method or not. Further on the study will investigate whether predictors exist and if they can be used to make the appropriate choice for surgical treatment for this patient group.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02051374 . First Posted: January 31, 2014. Last Update Posted: February 14, 2018.

The Role of Imaging in the Management of Cystic Formations of the Mobile Spine (CYFMOS)

PURPOSE OF REVIEW

The purpose of this review is to give a better understanding of the pathogenesis of cystic formations of the mobile spine (CYFMOS) and the correlating imaging findings. This would help with medical decision-making, given the plethora of conservative, interventional, and surgical treatment options.

RECENT FINDINGS

There has been a general understanding that CYFMOS are associated with degenerative spine changes. More recent articles however have suggested that identifying detailed imaging characteristics can assist in determining outcomes when CYFMOS are treated with interventional percutaneous methods or surgical decompression with or without concomitant fusion. CYFMOS although uncommon are not a rare finding seen in the spine when there is a background of degenerative spine changes. These cystic lesions are generally symptomatic by exhibiting mass effect on adjacent structure. Most treatments are aimed at decompression by interventional percutaneous or surgical means. Various imaging characteristics of these CYFMOS described in this article including their signal intensity, presence of spinal instability, particular patterns of adjacent degenerative changes, and imaging changes following interventional treatments can help guide physicians when managing these cases.