Facet Effusion without Radiographic Instability Has No Effect on the Outcome of Minimally Invasive Decompression Surgery

Reliability of facet fluid on preoperative MRI for prediction of segmental instability after decompression surgery for degenerative lumbar spinal stenosis

BACKGROUND

The purpose of this study is to determine whether preoperative facet fluid on MRI can help predict segmental instability (SI) after decompression surgery.

METHODS

We analyzed 34 patients (14 men and 20 women, a total of 37 segments) who underwent decompression for degenerative lumbar spinal stenosis from June 2011 to August 2019 at a single institution. Mean age at the time of operation was 67.8. Postoperative assessment was performed uniformly 12 months (11~15 months) after the surgery. Preoperative facet fluid on MRI, pre- and postoperative slip percentage, and segmental motion on lumbar lateral neutral and flexion-extension (LFE) radiographic images were measured. Visual Analog Scale (VAS) and necessities of interventional procedure or medication was also assessed for clinical outcomes.

RESULTS

No significant association was found between preoperative facet fluid indices and pre- or postoperative slip percentage (P=0.134) and segmental motion (P=0.936). There were no significant association also between facet fluid indices and VAS of back or leg (P=0.997 and P=0.437 respectively).

CONCLUSIONS

Preoperative facet fluid is not a predictive index of postoperative segmental instability or clinical outcome. Without segmental instability on LFE radiographic images, the presence of facet fluid in MRI is not an absolute indication for fusion.

Radiological Definitions of Sagittal Plane Segmental Instability in the Degenerative Lumbar Spine - A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVE

To collect and group definitions of segmental instability, reported in surgical studies of patients with lumbar spinal stenosis (LSS) and/or lumbar degenerative spondylolisthesis (LDS). To report the frequencies of these definitions. To report on imaging measurement thresholds for instability in patients and compare these to those reported in biomechanical studies and studies of spine healthy individuals.To report on studies that include a reliability study.

METHODS

This review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Studies eligible for inclusion were clinical and biomechanical studies on adult patients with LDS and/or LSS who underwent surgical treatment and had data on diagnostic imaging. A systematic literature search was conducted in relevant literature databases. Full text screening inclusion criteria was definition of segmental instability or any synonym. Two reviewers independently screened articles in a two-step process. Data synthesis presented by tabulate form and narrative synthesis.

RESULTS

We included 118 studies for data extraction, 69% were surgical studies with decompression or fusion as interventions, 31% non-interventional studies. Grouping the definitions of segmental instability according similarities showed that 24% defined instability by dynamic sagittal translation, 26% dynamic translation and dynamic angulation, 8% used a narrative definition. Comparison showed that non-interventional studies with a healthy population more often had a narrative definition.

CONCLUSION

Despite a reputation of non-consensus, segmental instability in the degenerative lumbar spine can radiologically be defined as > 3 mm dynamic sagittal translation.

Facet overhang: A novel parameter in the pathophysiology of multifidus muscle atrophy

The relationship between degenerative zygapophysial joint (facet) arthropathy and multifidus muscle atrophy has not been rigorously evaluated. The purpose of this study was to determine if specific morphological features of degenerative facet arthropathy are correlated with multifidus muscle atrophy. We retrospectively reviewed medical records and imaging studies of patients with lumbar spinal stenosis. Facet overhang, bridging osteophyte formation, facet effusion, and facet angles were evaluated by univariable and multivariable regression to identify independent associations with deep and superficial parts of the multifidus total cross-sectional area (tCSA), functional cross-sectional area (fnCSA), and fatty infiltration (FI). Facet overhang was classified as severe in 50 females (53.2%) versus 56 males (36.9%) (p = 0.030). Severity of facet overhang and female sex were independently associated with smaller deep part of the multifidus tCSA and fnCSA as well as higher FI, reflecting greater atrophy of the deep region compared to total muscle mass. In comparison, severe facet overhang (p < 0.001; OR = 3.47, 95% CI = 2.13-5.66) and female sex (p < 0.001; OR = 4.19, 95% CI = 2.58-6.79) were independently associated only with higher superficial part of the multifidus FI, reflecting muscle steatosis without significant lean muscle atrophy. In patients with degenerative lumbar spinal stenosis, facet overhang is an independent risk factor for deep part of the multifidus atrophy. Bridging osteophyte formation, facet effusion, and facet angles were not independently associated with deep part of the multifidus atrophy.

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.

Facet Joint Opening on Computed Tomography Is a Predictor of Poor Clinical Outcomes After Minimally Invasive Decompression Surgery for Lumbar Spinal Stenosis

STUDY DESIGN

Retrospective longitudinal cohort study.

OBJECTIVE

To investigate the impact of facet joint opening (FJO) on clinical outcomes after minimally invasive decompression surgery for lumbar spinal stenosis.

SUMMARY OF BACKGROUND DATA

Although FJOs have previously been identified as indicators of segmental spinal instability, their impact on clinical outcomes after decompression alone surgery has yet to be investigated.

METHODS

This study included 296 patients from a single institution who underwent minimally invasive surgery for lumbar spinal stenosis and were followed up for ≥5 years. Our analysis focused on identifying FJOs at the index decompression level (d-FJO) and at multiple levels (m-FJO) (i.e., ≥3 levels within the lumbar segment) using preoperative computed tomography. Clinical outcomes including reoperations, improvement ratio for Japanese Orthopaedic Association score, and achievement of a minimal clinically important difference in visual analogue scale scores for low back pain or leg pain at 5 years were compared between patients with and without d-FJO or m-FJO.

RESULTS

There were 129 (44%) and 62 (21%) patients with d-FJO (more common with lateral olisthesis) and m-FJO (less common with spondylolisthesis), respectively. Reoperations were more common in patients with d-FJO than in those without (16% vs. 5%). On Cox proportional hazards analysis, d-FJO was identified as a predictor for revision at the index decompression level (hazard ratio 4.04, P = 0.03), whereas m-FJO was a predictor for revision at other lumbar levels (hazard ratio 3.71, P = 0.03). Patients with m-FJO had slightly lower rates of achieving minimal clinically important difference in visual analogue scale scores for low back pain (34% vs. 52%, P = 0.03) and poorer improvement ratio for Japanese Orthopaedic Association scores (74% vs. 80%, P = 0.03) than those without.

CONCLUSION

FJO at both index decompression level and multiple level were predictors of poor outcomes; patients with FJOs require careful surgical planning or special follow-up.Level of Evidence: 3.

Risk factors for adjacent segment disease requiring reoperation after posterior lumbar interbody fusion with screw fixation: focus on paraspinal muscle, facet joint, and disc degeneration

PURPOSE

Adjacent segment disease (ASD) requiring revision surgery is the most serious complication that can occur in patients undergoing posterior lumbar interbody fusion (PLIF) surgery. This study aimed to determine the risk factors for surgical ASD requiring revision surgery after PLIF with screw fixation surgery. We especially focused on paraspinal muscle, facet joint, and disc degeneration.

METHODS

Among the patients who underwent PLIF with screw fixation due to degenerative spinal disease from January 2010 to December 2019, patients who underwent revision surgery for the development of ASD were enrolled. To evaluate the risk factors for surgical ASD, we selected a control group. Each patient in the control group was matched by age, sex, fusion level, number of fused segments, secondary MRI follow-up interval, and follow-up duration with a patient in the surgical ASD group. The radiographic and demographic data were compared between the surgical ASD and control groups.

RESULTS

There were statistically significant differences between the two groups in radiological parameters of preoperative facet degeneration, facet effusion, facet angle, and fatty degeneration of the multifidus muscle. Multivariable logistic regression analysis revealed that preoperative facet effusion (odds ratio [OR] 6.48), preoperative facet angle (OR 1.24), and progression of fatty degeneration in the multifidus muscle (OR 1.07) were significant risk factors for surgical ASD.

CONCLUSIONS

Preexisting high-grade adjacent facet effusion, sagittally oriented facet joint angle, and progressive fatty degeneration of the multifidus muscle are associated with the development of surgical ASD after PLIF surgery.

Relationship between facet joint opening on CT and facet joint effusion on MRI in patients with lumbar spinal stenosis: analysis of a less invasive decompression procedure

OBJECTIVE

Both facet joint opening (FJO) on CT and facet joint effusion (FJE) on MRI are reportedly indicators of segmental instability in the lumbar facet joints of patients with lumbar spinal stenosis (LSS). However, no study has investigated both parameters simultaneously. Therefore, the association between these findings and which parameter is better for predicting clinical outcomes after surgical treatment remains unclear. The purpose of this study was to investigate the relationship between FJO and FJE in patients who underwent less invasive decompression procedures for LSS and to investigate the impact of these findings on clinical outcomes.

METHODS

This study included 1465 lumbar levels (L1-2 to L5-S1) in 293 patients who underwent less invasive surgery for LSS and had ≥ 5 years of follow-up. FJO was defined as joint space widening ≥ 2 mm on preoperative axial CT images. FJE was defined as fluid effusion in the facet joint on preoperative axial T2-weighted MR images. The characteristics and distributions of FJO and FJE were investigated with other preoperative radiological findings. The association between need for further surgery and FJO/FJE was analyzed according to intervertebral level.

RESULTS

FJO was observed at 402 levels (27%), and FJE was found at 306 levels (21%). The correspondence rate between FJO and FJE was 70% (kappa 0.195, p < 0.01). One hundred thirty-seven levels (9%) had both FJO and FJE. Levels with both FJO and FJE more commonly had lateral olisthesis, lateral wedging, and axial intervertebral rotation than other levels (p < 0.001). Levels with both FJO and FJE were more likely than other levels to need further surgery (OR 2.42, p = 0.027).

CONCLUSIONS

The correspondence rate between FJO and FJE was not high. However, multivariate analysis showed that levels with both FJO and FJE had a higher risk of requiring further surgery than those with other radiological findings, such as lateral olisthesis, lateral wedging, and axial intervertebral rotation. Patients with levels with both FJO and FJE need careful long-term follow-up after undergoing a less invasive decompression procedure.

Incidence and significance of findings on spinal MRIs in a paediatric population with spinal column complaints

PURPOSE

We sought to identify correlations between working diagnosis, surgeon indication for obtaining spinal MRI and positive MRI findings in paediatric patients presenting with spinal disorders or complaints.

METHODS

Surgeons recorded their primary indication for ordering a spinal MRI in 385 consecutive patients. We compared radiologist-reported positive MRI findings with surgeon response, indication, working diagnosis and patient demographics.

RESULTS

The most common surgeon-stated indications were pain (70) and coronal curve characteristics (63). Radiologists reported 137 (36%) normal and 248 (64%) abnormal MRIs. In total, 58% of abnormal reports (145) did not elicit a therapeutic or investigative response, which we characterized as 'clinically inconsequential'. In all, 42 of 268 (16%) presumed idiopathic scoliosis patients had intradural pathology noted on MRI.Younger age (10.3 years versus 12.0 years) was the only significant demographic difference between patients with or without intradural pathology. Surgeon indication 'curve magnitude at presentation' was associated with intradural abnormality identification. However, average Cobb angles between patients with or without an intradural abnormality was not significantly different (39° versus 37°, respectively). Back pain without neurological signs or symptoms was a negative predictor of intradural pathology.

CONCLUSION

Radiologists reported a high frequency of abnormalities on MRI (64%), but 58% of those were deemed clinically inconsequential. Patients with MRI abnormalities were two years' younger than those with a normal or inconsequential MRI. 'Curve magnitude at presentation' in presumed idiopathic scoliosis patients was the only predictor of intrathecal pathology. 'Pain' was the only indication significantly associated with clinically inconsequential findings on MRI.

LEVEL OF EVIDENCE

III.

Anatomy and pathology of facet joint

Facet joints are the only synovial joints in the spine and can be involved in a large number of pathological processes including arthropathy, infection, inflammation, trauma and tumour. In this review article, we present a spectrum of pathologies that arise from or involve facet joints that we have encountered in our tertiary orthopaedic and spinal centre. The objective of this review is to create an aide memoire for the general radiologist who may encounter facet joint pathology, which they may not be familiar with.

New classification of facet joint synovial cysts

PURPOSE

Facet cysts develop due to degeneration of the zygapophyseal joints and can lead to radiculopathy and neurogenic claudication. Various surgical options are available for facet cyst excision. The aim was to facilitate surgical treatment of lumbar facet cysts based on a new classification.

METHODS

We retrospectively analyzed all patients of the last 10 years in whom a facet cyst was surgically removed (ipsilateral laminotomy, contralateral laminotomy, and segmental fusion). Several radiological parameters were analyzed and correlated with the patients' outcome (residual symptoms, perioperative complications, need for re-operation, need for secondary fusion, facet cyst recurrence).

RESULTS

One hundred eleven patients (55 women; median age 64 years) could be identified. Thirty-three (48%) of 69 cases, for which MRI data were available, were classified as medial facet cyst (compressing the spinal canal), 6 facet cysts were localized intraforaminal (9%) and 30 cases (43%) mediolateral (combination of both). The contralateral approach had the lowest rate for revision surgery (7.5%, p = .038) and the lowest prevalence of residual complaints (7.5%, p = .109). A spondylolisthesis and a higher/steeper angle of the facet joints were associated with poorer patient outcome.

CONCLUSIONS

Lateral facet joint cysts are best resected by a contralateral approach offering the best outcome while medial cysts are suitable for removal by an ipsilateral laminotomy. The approach of mediolateral cysts can be determined by the width of the lamina and the angle of the joint. Segmental fusion should be considered in cases with detected spondylolisthesis and/or steep facet joints.

Trans-foraminal endoscopic uniportal decompression in degenerative lumbar spondylolisthesis: a technical and case report

Background

Degenerative spondylolisthesis is a common spinal pathology. Traditionally, spinal fusion is an accepted standard surgical treatment for listhesis. But fusion is a major intervention with its known pitfalls. With technological progression, minimally invasive spinal fusion (MISF) procedures are becoming mainstream. Percutaneous trans-foraminal endoscopic lumbar discectomy/decompressions (PTELD) without stabilization has many advantages over even a MISF for select group of patients.

Case presentation

In this case report, we describe using a uniportal unilateral trans-foraminal approach (TFA) for stable listhesis with lumbar disc herniation (LDH) causing chronic bilateral radicular symptoms and back pain with acute exacerbation. Under local anesthesia, we used a flat entry for PTELD, which facilitates an approach to both disc sides ventrally and even dorsal aspect lateral recess decompression on the dominant ipsilateral side. No fixation was done. An excellent outcome is obtained immediately at 6 weeks and maintained at 39 months of follow-up.

Conclusion

PTELD is worth considering as an intermediate procedure before fusion is offered in lateral recess stenosis in stable listhesis patients who have consented and understand the progressive cascade of spinal degeneration.

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.