Spinal implant wear particles: Generation, characterization, biological impacts, and future considerations

The generation of wear debris from orthopedic implants is a known cause of implant failure, particularly in joint replacements. While much research has focused on wear particles from knee and hip implants, spinal implants, such as total disc replacements (TDRs), have received less attention despite their increasing clinical use. Spinal implants face unique biomechanical challenges, including a wider range of motion and higher loads, leading to complex tissue interactions. Studies reveal that TDR wear particles, though similar in size to those from knee implants, cause a stronger immune response, with more macrophages and giant cells found in the surrounding tissue. This may explain the high revision rates seen in spinal surgeries, with some interventions failing in over 30% of cases within 10 years. The younger population undergoing spinal surgery, combined with the productivity losses associated with implant failure, underscores the need for greater understanding. This review discusses recent research on the generation, characterization, and biological impacts of spinal implant wear debris. It draws on retrieval analysis, wear simulation, in vivo models, and a survey conducted with the AO Spine Knowledge Forum Degenerative to assess current clinical practices and highlight gaps in knowledge. Additionally, this critical review explores future strategies to reduce the biological impact of wear particles and improve the safety and longevity of spinal implants through better therapeutics and design innovations. By combining literature and clinical insights, this paper aims to guide future research in addressing the complexities of spinal implant wear and its biological consequences.

AI-based lumbar central canal stenosis classification on sagittal MR images is comparable to experienced radiologists using axial images

OBJECTIVES

The assessment of lumbar central canal stenosis (LCCS) is crucial for diagnosing and planning treatment for patients with low back pain and neurogenic pain. However, manual assessment methods are time-consuming, variable, and require axial MRIs. The aim of this study is to develop and validate an AI-based model that automatically classifies LCCS using sagittal T2-weighted MRIs.

METHODS

A pre-existing 3D AI algorithm was utilized to segment the spinal canal and intervertebral discs (IVDs), enabling quantitative measurements at each IVD level. Four musculoskeletal radiologists graded 683 IVD levels from 186 LCCS patients using the 4-class Lee grading system. A second consensus reading was conducted by readers 1 and 2, which, along with automatic measurements, formed the training dataset for a multiclass (grade 0-3) and binary (grade 0-1 vs. 2-3) random forest classifier with tenfold cross-validation.

RESULTS

The multiclass model achieved a Cohen's weighted kappa of 0.86 (95% CI: 0.82-0.90), comparable to readers 3 and 4 with 0.85 (95% CI: 0.80-0.89) and 0.73 (95% CI: 0.68-0.79) respectively. The binary model demonstrated an AUC of 0.98 (95% CI: 0.97-0.99), sensitivity of 93% (95% CI: 91-96%), and specificity of 91% (95% CI: 87-95%). In comparison, readers 3 and 4 achieved a specificity of 98 and 99% and sensitivity of 74 and 54%, respectively.

CONCLUSION

Both the multiclass and binary models, while only using sagittal MR images, perform on par with experienced radiologists who also had access to axial sequences. This underscores the potential of this novel algorithm in enhancing diagnostic accuracy and efficiency in medical imaging.

KEY POINTS

Question How can the classification of lumbar central canal stenosis (LCCS) be made more efficient? Findings Multiclass and binary AI models, using only sagittal MR images, performed on par with experienced radiologists who also had access to axial sequences. Clinical relevance Our AI algorithm accurately classifies LCCS from sagittal MRI, matching experienced radiologists. This study offers a promising tool for automated LCCS assessment from sagittal T2 MRI, potentially reducing the reliance on additional axial imaging.

Correlation between paraspinal muscle fat infiltration and thoracic vertebral degeneration based on phantom-less QCT: a novel insight into thoracic vertebral degeneration

PURPOSE

This study aimed to elucidate the correlation between the degree of fat infiltration (FI) in thoracic paraspinal muscles and thoracic vertebral degeneration (TVD).

METHODS

This cross-sectional study comprised 474 patients who underwent standard thoracic computed tomography (CT) scans. The FI was quantified as the percentage of adipose tissues within the cross-sectional area of thoracic paraspinal muscles. Thoracic vertebra was assessed in terms of osteoporosis, ossification of the anterior longitudinal ligament (OALL), ossification of the posterior longitudinal ligament (OPLL), intervertebral disc calcification, intervertebral disc cavity, and facet joint osteoarthritis (FJO). Logistic regression, linear regression, subgroup, and receiver operating characteristic (ROC) analyses were assessed to evaluate the association between FI and TVD.

RESULTS

Multivariate logistic regression revealed that more severe FI was closely associated with more serious osteoporosis (P < 0.001). Furthermore, after adjusting for only age, higher FI was significantly associated with nastier FJO (P < 0.05). In male patients, severe FI was greatly associated with worse osteoporosis (P < 0.05). In female patients, severe FI maintained close correlations with more severe osteoporosis and FJO (P < 0.05). Furthermore, in patients aged < 60 or ≥ 60 years, higher FI had a strong correlation with more severe osteoporosis (P < 0.001). In patients aged < 60 years, higher FI was associated with worse intervertebral disc calcification, OALL, and FJO (P < 0.05). Meanwhile, in patients aged ≥ 60 years, increased FI was only associated with severe OPLL (P < 0.05). Multivariate linear regression showed that FI negatively correlated with bone mineral density in the general population and different sex and age groups (P < 0.001). ROC analysis indicated that FI could predict the occurrence of TVD (P < 0.05).

CONCLUSION

Higher FI is associated with more severe TVD. Studies on TVD are currently limited; therefore, this study enriches the related research on TVD, and our findings would facilitate the early prediction and diagnosis of TVD in clinical practice. Furthermore, our findings indicate that thoracic spine pain (TSP) caused by TVD can be prevented, potentially improving the prognosis of patients with TSP.

Indication and Technical Consideration for Nerve Blocks and Neurolysis for Pain Control

Pain management in interventional radiology (IR) encompasses a variety of advanced image-guided techniques to deliver minimally invasive treatments for various pain conditions. Key procedures include nerve blocks and neurolysis, which target specific nerves to provide substantial pain relief. Effective pain management in IR relies on a thorough understanding of regional anatomy, precise technique, and careful administration of local anesthetics, neurolytic agents, and corticosteroids. Complications are minimized through strict adherence to dosage guidelines and meticulous procedural protocols. These interventions significantly improve patient outcomes, reduce recovery times, and minimize the risk of chronic pain, underscoring the pivotal role of IR in contemporary pain management. In the present review, we will report the most common nerve blocks and neurolytic interventions performed in the IR field, by focusing on anatomy, imaging guidance, major procedural points, and expected complications.

Association between MRI measurements of lumbar spine alterations and self-reported outcomes of pain and disability in subjects with non-specific low back pain

PURPOSE

This study aims to elucidate the association between MRI measurements of spine alterations and self-reported outcomes of pain and disability in individuals with non-specific low back pain, using a comprehensive perspective based on machine learning algorithm.

METHODS

246 consecutive subjects were assessed. Pain severity in cervical, lumbar, and leg regions was determined using visual analogue scale, and functional disability was acquired by Oswestry Disability Index. Sagittal and axial MRI scans of the thoracolumbar spine were evaluated. Severity of disc degeneration, spinal canal stenosis, and presence of vertebral endplate lesions based on two different classification schemes involving the extent and the shape of defects were quantified at the levels from T12L1 to L5S1. The following parameters describing the lumbar region as a whole were calculated: maximum value along spinal levels, sum of values along levels, number of levels characterized by severe condition. The association with pain and disability was assessed by generalized multiple linear regression modelling.

RESULTS

Disc degeneration was identified as a predictor of disability and partially of pain, whereas canal stenosis was found associated with changes in pain in the leg region. Partial correlation values ranged from 0.11 to 0.32. Endplate lesions did not show significant associations.

CONCLUSION

A partial association between MRI measurements and self-reported outcomes of pain and disability was confirmed. Disc degeneration was the most correlated with the reported indexes, while canal stenosis mainly affected the pain levels in the leg region. The presence of endplate lesions did not demonstrate any significant relationships.

Characterization of annulus fibrosus lesions on magnetic resonance imaging in dogs affected by intervertebral disc disease, a descriptive case series

Objective

Describe and characterize the magnetic resonance imaging (MRI) appearance of annulus fibrosus (AF) high-intensity zone (HIZ) in dogs suffering from intervertebral disc disease (IVDD).

Methods

A single-center retrospective case series study. Databases were reviewed from 2011 to 2022 for dogs that underwent MRI diagnosis due to suspected IVDD. Cases were included if they had T2-weighted (T2W) hyperintense annular fibrosus lesions (AFL) on the imaging diagnosis report. To be included, the MRI scan had to be of diagnostic quality and include a sagittal T2W, proton density (PD), or short tau inversion recovery (STIR) sequence of the annular lesion, together with transverse T2W and/or dorsal plane STIR sequences over the HIZ region.

Results

Forty one cases (in 39 dogs) of HIZ were included in the study. Mixed breed dogs were the highest represented group representing 25.6% of the cohort. Patient median age was 7.5 years and median weight 23 kg. Primary HIZ appeared in 7/39 dogs (17.95%) and the remaining had acute non-compressive nucleus pulposus extrusion (ANNPE), hydrated nucleus pulposus extrusion (HNPE) or concurrent myelopathy. Characterization of HIZ lesions included several variable appearances in orientation and shape. HIZ lesions were most easily identifiable in the sagittal plane. Similar to humans, the most common site of HIZ without extrusion was the lumbosacral (LS) region. All the dogs with HIZ lesions as the most significant MRI finding, exhibited spinal pain and/or chronic paresis/plegia.

Conclusions and clinical significance

By introducing and defining HIZ lesions to the veterinary imaging nomenclature, we hope future studies will further examine the prevalence and clinical significance of HIZ lesions in canine patients.

Spine Pain

OBJECTIVE

Spine pain is one of the most common presenting concerns in health care settings. This article reviews clinical strategies for evaluating and managing patients with spine pain.

LATEST DEVELOPMENTS

Minimally invasive interventional procedures, virtual reality, predictive analytics, neuromodulation, and other evolving technologies are significantly impacting the management of spine pain. Advances in modern pain science have also led to effective skills and treatment strategies, including patient interviews and queries for insight regarding pain, education, and cognitive restructuring, and adjusting the timing of examination (after reeducation) and examination techniques to encourage the experience of movement in the absence of assumed tissue damage. An evolving understanding of the influence of patient-centric thoughts, framing, emotional status, and cognitive restructuring's influence on the brain's response to perceived threat are important aspects of spine pain management.

ESSENTIAL POINTS

The correlation of clinical presentations with structural abnormalities is necessary but insufficient to evaluate and manage spine pain. Modern pain science acknowledges pain as a subjective experience but recognizes a critical distinction between tissue damage, nociception, and the experience of pain. What and how we communicate with patients, as well as evolving neuromodulation technologies, augment conventional approaches.

Development and validation of AI-based automatic measurement of coronal Cobb angles in degenerative scoliosis using sagittal lumbar MRI

OBJECTIVES

Severity of degenerative scoliosis (DS) is assessed by measuring the Cobb angle on anteroposterior radiographs. However, MRI images are often available to study the degenerative spine. This retrospective study aims to develop and evaluate the reliability of a novel automatic method that measures coronal Cobb angles on lumbar MRI in DS patients.

MATERIALS AND METHODS

Vertebrae and intervertebral discs were automatically segmented using a 3D AI algorithm, trained on 447 lumbar MRI series. The segmentations were used to calculate all possible angles between the vertebral endplates, with the largest being the Cobb angle. The results were validated with 50 high-resolution sagittal lumbar MRI scans of DS patients, in which three experienced readers measured the Cobb angle. Reliability was determined using the intraclass correlation coefficient (ICC).

RESULTS

The ICCs between the readers ranged from 0.90 (95% CI 0.83-0.94) to 0.93 (95% CI 0.88-0.96). The ICC between the maximum angle found by the algorithm and the average manually measured Cobb angles was 0.83 (95% CI 0.71-0.90). In 9 out of the 50 cases (18%), all readers agreed on both vertebral levels for Cobb angle measurement. When using the algorithm to extract the angles at the vertebral levels chosen by the readers, the ICCs ranged from 0.92 (95% CI 0.87-0.96) to 0.97 (95% CI 0.94-0.98).

CONCLUSION

The Cobb angle can be accurately measured on MRI using the newly developed algorithm in patients with DS. The readers failed to consistently choose the same vertebral level for Cobb angle measurement, whereas the automatic approach ensures the maximum angle is consistently measured.

CLINICAL RELEVANCE STATEMENT

Our AI-based algorithm offers reliable Cobb angle measurement on routine MRI for degenerative scoliosis patients, potentially reducing the reliance on conventional radiographs, ensuring consistent assessments, and therefore improving patient care.

KEY POINTS

• While often available, MRI images are rarely utilized to determine the severity of degenerative scoliosis. • The presented MRI Cobb angle algorithm is more reliable than humans in patients with degenerative scoliosis. • Radiographic imaging for Cobb angle measurements is mitigated when lumbar MRI images are available.

Evidence of MRI image features and inflammatory biomarkers association with low back pain in patients with lumbar disc herniation

BACKGROUND CONTEXT

While MRI image features and inflammatory biomarkers are frequently used for guiding treatment decisions in patients with lumbar disc herniation (LDH) and low back pain (LBP), our understanding of the connections between these features and LBP remains incomplete. There is a growing interest in the potential significance of MRI image features and inflammatory biomarkers, both for quantification and as emerging therapeutic tools for LBP.

PURPOSE

To investigate the evidence supporting MRI image features and inflammatory biomarkers as predictors of LBP and to determine their relationship with pain intensity.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

All consecutive patients with LDH who underwent discectomy surgery at our institution from February 2020 to June 2023 at the author's institution were included.

OUTCOME MEASURES

MRI image features in discogenic, osseous, facetogenic, and paraspinal muscles, as well as inflammatory biomarkers in serum (including CRP (C-reactive protein), ESR (erythrocyte sedimentation rate), PCT (procalcitonin), TNF (tumor necrosis factor), interleukin-1 beta (IL-1β), and IL-6), and paraspinal muscles (including TNF, IL-1β, IL-6, IL-10, and transforming growth factor beta 1 (TGF-β1)).

METHODS

A series of continuous patients diagnosed with LDH were categorized into acute LBP (<12 weeks), chronic LBP (≥12 weeks), and nonLBP groups. MRI image features and inflammatory biomarkers relation to pain intensity was assessed using the independent t-test, Chi-squared tests, Spearman rank correlation coefficient, and logistic regression test.

RESULTS

Compared to the nonLBP group, the chronic LBP group exhibited a higher incidence of intervertebral disc (IVD) degeneration (≥ grade 3) and high-fat infiltration in paraspinal muscles, alongside a significant reduction in the cross-sectional area (CSA) and fatty degeneration of the multifidus muscle. Furthermore, there was a greater expression of IL-6 in serum and TNF in paraspinal muscles in the chronic LBP group and a greater expression of CRP and IL-6 in serum and TNF in paraspinal muscles in the acute LBP group. CSA and fatty degeneration of multifidus muscle were moderately negatively correlated with chronic LBP scores. The expression of TNF and IL-6 in serum and the expression of TNF in the multifidus muscle were moderately correlated with preoperative LBP. IVD degeneration and high-fat infiltration were identified as risk factors for chronic LBP.

CONCLUSION

The results provide evidence that IVD degeneration, high-fat infiltration, and the reduction of CSA in paraspinal muscles were associated with the development of chronic LBP in patients with LDH, and these associations are linked to inflammatory regulation. This deepens our understanding of the etiology and pathophysiology of LBP, potentially leading to improved patient stratification and more targeted interventions.

Comparing CT-Like Images Based on Ultra-Short Echo Time and Gradient Echo T1-Weighted MRI Sequences for the Assessment of Vertebral Disorders Using Histology and True CT as the Reference Standard

BACKGROUND

Several magnetic resonance (MR) techniques have been suggested for radiation-free imaging of osseous structures.

PURPOSE

To compare the diagnostic value of ultra-short echo time and gradient echo T1-weighted MRI for the assessment of vertebral pathologies using histology and computed tomography (CT) as the reference standard.

STUDY TYPE

Prospective.

SUBJECTS

Fifty-nine lumbar vertebral bodies harvested from 20 human cadavers (donor age 73 ± 13 years; 9 male).

FIELD STRENGTH/SEQUENCE

Ultra-short echo time sequence optimized for both bone (UTEb) and cartilage (UTEc) imaging and 3D T1-weighted gradient-echo sequence (T1GRE) at 3 T; susceptibility-weighted imaging (SWI) gradient echo sequence at 1.5 T. CT was performed on a dual-layer dual-energy CT scanner using a routine clinical protocol.

ASSESSMENT

Histopathology and conventional CT were acquired as standard of reference. Semi-quantitative and quantitative morphological features of degenerative changes of the spines were evaluated by four radiologists independently on CT and MR images independently and blinded to all other information. Features assessed were osteophytes, endplate sclerosis, visualization of cartilaginous endplate, facet joint degeneration, presence of Schmorl's nodes, and vertebral dimensions. Vertebral disorders were assessed by a pathologist on histology.

STATISTICAL TESTS

Agreement between T1GRE, SWI, UTEc, and UTEb sequences and CT imaging and histology as standard of reference were assessed using Fleiss' κ and intra-class correlation coefficients, respectively.

RESULTS

For the morphological assessment of osteophytes and endplate sclerosis, the overall agreement between SWI, T1GRE, UTEb, and UTEc with the reference standard (histology combined with CT) was moderate to almost perfect for all readers (osteophytes: SWI, κ range: 0.68-0.76; T1GRE: 0.92-1.00; UTEb: 0.92-1.00; UTEc: 0.77-0.85; sclerosis: SWI, κ range: 0.60-0.70; T1GRE: 0.77-0.82; UTEb: 0.81-0.92; UTEc: 0.61-0.71). For the visualization of the cartilaginous endplate, UTEc showed the overall best agreement with the reference standard (histology) for all readers (κ range: 0.85-0.93).

DATA CONCLUSIONS

Morphological assessment of vertebral pathologies was feasible and accurate using the MR-based bone imaging sequences compared to CT and histopathology. T1GRE showed the overall best performance for osseous changes and UTEc for the visualization of the cartilaginous endplate.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 2.

Association between the Thickness of Lumbar Subcutaneous Fat Tissue and the Presence of Hernias in Adults with Persistent, Non-Traumatic Low Back Pain

We aimed to analyze the association between the average lumbar subcutaneous fat tissue thickness (LSFTT) at each intervertebral level and the presence of hernias in patients with low back pain from an insurance network hospital in Mexico. This observational prospective study included 174 patients with non-traumatic lumbago who underwent magnetic resonance imaging with a 1.5T resonator. Two independent radiologists made the diagnosis, and a third specialist provided a quality vote when needed. The sample size was calculated with a 95% confidence interval using random order selection. Anonymized secondary information was used. Percentages and means with confidence intervals were tabulated. The area under the curve, specificity, and sensitivity of LSFTT were calculated. A regression analysis was performed to analyze the presence of hernias with LSFTT using each intervertebral level as a predictor. The odds of herniation at any intervertebral level increased directly with LSFTT. The average LSFTT predicted the overall presence of hernias; however, the LSFTT at each intervertebral level better predicted hernias for each intervertebral space. The area under the curve for LSFTT in predicting hernias was 68%. In conclusion, the average LSFTT was associated with the overall presence of hernias; patients with more hernias had higher LSFTT values.

Virtual Reality Therapy for the Management of Chronic Spinal Pain: Systematic Review and Meta-Analysis

BACKGROUND

The effectiveness of virtual reality (VR) therapy in adults with chronic spinal pain (CSP) is unclear.

OBJECTIVE

This study was conducted to compare the effectiveness of VR therapy and other therapies in adults with CSP, especially patients with inflammation-related pain.

METHODS

PubMed, Web of Science, Cochrane Library, Embase, and CINAHL databases were searched up to November 11, 2023. Randomized controlled trials (RCTs) comparing adults with CSP receiving VR therapy with those receiving other therapies were included. The trial registration platform as well as the reference lists of included studies and previous systematic reviews and meta-analyses were manually searched. Two independent reviewers performed study selection, data extraction, risk-of-bias assessment, and evaluation of the quality of the evidence. The weighted mean difference (WMD) was used as the effect size used to synthesize the outcome measure.

RESULTS

In total, 16 RCTs involving 800 participants were included in this meta-analysis. The pooled data from 15 (94%) RCTs including 776 (97%) participants showed that VR therapy was superior in improving pain intensity (WMD=-1.63, 95% CI -2.11 to -1.16, P<.001, I2=90%) and reducing inflammatory markers, including C-reactive protein (WMD=-0.89, 95% CI -1.07 to -0.70, P<.001, I2=0%), tumor necrosis factor-alpha (WMD=-6.60, 95% CI -8.56 to -4.64, P<.001, I2=98%), and interleukin-6 (WMD=-2.76, 95% CI -2.98 to -2.53, P<.001, I2=0%). However, no significant differences were found in terms of the spinal range of motion (ROM), disability level, or fear of movement. In addition, 10 (63%) of the included RCTs had a high risk of bias.

CONCLUSIONS

VR therapy may be an effective and safe intervention for reducing symptoms in patients with CSP, as it is shown to exert significant analgesic effects and beneficial improvements in inflammatory factor levels. However, this approach may not have significant effects on the spinal ROM, disability level, or fear of movement. Notably, the quality of the evidence from the RCTs included in this study ranged from moderate to low. Therefore, we recommend that readers interpret the results of this study with caution.

TRIAL REGISTRATION

PROSPERO CRD42022382331; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=382331.

Efficacy of stepped care treatment for chronic discogenic low back pain patients with Modic I and II changes

Objective

This study investigated whether patients with Modic changes (MC) of types I, I/II, and II would respond to an anti-inflammatory-based, stepped care treatment with three treatment steps: first, oral administration of NSAIDs, 2 × 200 mg celecoxib daily for two weeks; second, an intradiscal steroid injection (ID) with dexamethasone and cefazolin; and third, oral treatment with antibiotics (AB), 3 × 1 g amoxicillin daily for 100 days.

Design

This was an observational clinical study based on analyses of categorical data of patient-reported outcome measurements.

Subjects

Subjects were consecutive patients with chronic low back pain (CLBP), diagnosed by assessment of anamnestic signs of inflammation; a pain score ≥6 on the Numeric Pain Rating Scale (NPRS); a mechanical assessment; MC I, I/II, or II based on MRI; and lack of response to conservative treatment.

Methods

From January 1, 2015, to December 31, 2021, 833 eligible patients were selected for the stepped care treatment. A total of 332 patients completed requested follow-up questionnaires at baseline and 12 months (optional at 3 and 6 months). Primary outcomes were pain (at least 50 % pain relief) and/or a minimum of 40 % improvement in functionality as measured by the Roland Morris Disability Questionnaire (RMDQ) or the Oswestry Disability Questionnaire (ODI). Secondary outcome measures were use of pain medication and return to work.

Results

At 1 year of follow-up, 179 (53.6 %) of 332 patients reported improvement according to the responder criteria. Of the 138 patients that had received only NSAIDs, 88 (63.8 %) had improved. In addition, 50 (56.8 %) of the 183 patients that had received ID had improved, and 41 (38.7 %) of the 106 patients treated with AB had improved. None of the patients reported complications. 12.0 % of patients using AB stopped preterm due to undesirable side effects.

Conclusion

Treatment with a stepped care model for inflammatory pain produced clinically relevant, positive reported outcomes on pain and/or function. Our stepped care model appears to be a useful, safe, and cost-saving treatment option that is easily reproducible. Further studies, including randomized controlled trials and analyses of subgroups, may help to develop a more patient-tailored approach and further avoidance of less-effective treatments and costs.

Symptom-imaging correlation in lumbar spine pain

Lumbar spine MRI is associated with a high prevalence of morphological abnormalities in both symptomatic and asymptomatic individuals. A difficult challenge, therefore, is distinguishing the relevant findings causing symptoms from incidental findings. The accurate diagnosis of pain generator is important because misdiagnosis can negatively impact patient management and outcome. Spine physicians use clinical symptoms and signs to interpret lumbar spine MRI and make treatment decisions. Symptom-MRI correlation enables the targeted inspection of images for pain generator. Radiologists can also use clinical information to improve diagnostic confidence and the value of dictated reports. Because high-quality clinical information may be difficult to obtain, radiologists often generate lists of lumbar spine abnormalities that are otherwise difficult to rank as pain generators. Based on the literature review, this article attempts to distinguish the MRI abnormalities that may represent incidental findings from the abnormalities that are more commonly associated with lumbar spine-related symptoms.

A Scalable Radiomics- and Natural Language Processing-Based Machine Learning Pipeline to Distinguish Between Painful and Painless Thoracic Spinal Bone Metastases: Retrospective Algorithm Development and Validation Study

BACKGROUND

The identification of objective pain biomarkers can contribute to an improved understanding of pain, as well as its prognosis and better management. Hence, it has the potential to improve the quality of life of patients with cancer. Artificial intelligence can aid in the extraction of objective pain biomarkers for patients with cancer with bone metastases (BMs).

OBJECTIVE

This study aimed to develop and evaluate a scalable natural language processing (NLP)- and radiomics-based machine learning pipeline to differentiate between painless and painful BM lesions in simulation computed tomography (CT) images using imaging features (biomarkers) extracted from lesion center point-based regions of interest (ROIs).

METHODS

Patients treated at our comprehensive cancer center who received palliative radiotherapy for thoracic spine BM between January 2016 and September 2019 were included in this retrospective study. Physician-reported pain scores were extracted automatically from radiation oncology consultation notes using an NLP pipeline. BM center points were manually pinpointed on CT images by radiation oncologists. Nested ROIs with various diameters were automatically delineated around these expert-identified BM center points, and radiomics features were extracted from each ROI. Synthetic Minority Oversampling Technique resampling, the Least Absolute Shrinkage And Selection Operator feature selection method, and various machine learning classifiers were evaluated using precision, recall, F1-score, and area under the receiver operating characteristic curve.

RESULTS

Radiation therapy consultation notes and simulation CT images of 176 patients (mean age 66, SD 14 years; 95 males) with thoracic spine BM were included in this study. After BM center point identification, 107 radiomics features were extracted from each spherical ROI using pyradiomics. Data were divided into 70% and 30% training and hold-out test sets, respectively. In the test set, the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of our best performing model (neural network classifier on an ensemble ROI) were 0.82 (132/163), 0.59 (16/27), 0.85 (116/136), and 0.83, respectively.

CONCLUSIONS

Our NLP- and radiomics-based machine learning pipeline was successful in differentiating between painful and painless BM lesions. It is intrinsically scalable by using NLP to extract pain scores from clinical notes and by requiring only center points to identify BM lesions in CT images.

MRI image features with an evident relation to low back pain: a narrative review

PURPOSE

Low back pain (LBP) is one of the most prevalent health condition worldwide and responsible for the most years lived with disability, yet the etiology is often unknown. Magnetic resonance imaging (MRI) is frequently used for treatment decision even though it is often inconclusive. There are many different image features that could relate to low back pain. Conversely, multiple etiologies do relate to spinal degeneration but do not actually cause the perceived pain. This narrative review provides an overview of all possible relevant features visible on MRI images and determines their relation to LBP.

METHODS

We conducted a separate literature search per image feature. All included studies were scored using the GRADE guidelines. Based on the reported results per feature an evidence agreement (EA) score was provided, enabling us to compare the collected evidence of separate image features. The various relations between MRI features and their associated pain mechanisms were evaluated to provide a list of features that are related to LBP.

RESULTS

All searches combined generated a total of 4472 hits of which 31 articles were included. Features were divided into five different categories:'discogenic', 'neuropathic','osseous', 'facetogenic', and'paraspinal', and discussed separately.

CONCLUSION

Our research suggests that type I Modic changes, disc degeneration, endplate defects, disc herniation, spinal canal stenosis, nerve compression, and muscle fat infiltration have the highest probability to be related to LBP. These can be used to improve clinical decision-making for patients with LBP based on MRI.

Magnetic resonance spectroscopy (MRS) identification of chemically painful lumbar discs leads to improved 6-, 12-, and 24-month outcomes for discogenic low back pain surgeries

PURPOSE

MRS was shown to reliably quantify relative levels of degenerative pain biomarkers, differentiating painful versus non-painful discs in patients with chronic discogenic low back pain (DLBP), and this correlates with surgical success rates. We now report results based on more patients and longer follow-up.

METHODS

Disc MRS was performed in DLBP patients who subsequently received lumbar surgery. Custom post-processing (NOCISCAN-LS®; Aclarion Inc.) calculated disc-specific NOCISCORES® that reflect relative differences in degenerative pain biomarkers for diagnosing chemically painful discs. Outcomes in 78 patients were evaluated using Oswestry Disability Index (ODI) scores. Surgical success (≥ 15-point ODI improvement) was compared between surgeries that were "Concordant" (Group C) versus "Discordant" (Group D) with NOCISCORE-based diagnosis for painful discs.

RESULTS

Success rates were higher for Group C versus Group D: 6 months (88% vs. 62%; p = 0.01), 12 months (91% vs. 56%; p < 0.001), and 24 months (85% vs. 63%; p = 0.07). Success rates for Group C surgeries were also higher than Group D surgeries in a variety of sub-group comparisons. Group C had a greater reduction in ODI from pre-operative to follow-up than Group D [absolute change (% change), (p)]: 6 months: - 35 (- 61%) versus - 23 (- 39%), (p < 0.05); 12 months: - 39 (- 69%) versus - 22 (- 39%), (p < 0.01); and 24 months:  - 38 (- 66%) versus - 26 (- 48%), (p < 0.05).

CONCLUSION

More successful, sustained outcomes were obtained when surgically treating chemically painful discs identified by NOCISCAN-LS post-processed disc MRS exams. Results suggest that NOCISCAN-LS provides a valuable new diagnostic tool to help clinicians better select treatment levels.

Manual handling amongst physiotherapists: Analysis of intra-shift variations in pain, fatigue and movement

BACKGROUND

Manual handling injuries amongst physiotherapists are common and the need to improve our understanding of causal influences is imperative.

OBJECTIVE

The objective was to determine whether intra-shift variations in manual handling task performance occurred in our cohort, which may inform mechanisms underpinning related injuries.

METHODS

We used motion capture, force plate dynamics and electromyography to identify variations in task performance, loading forces and muscle activity, during the performance of one static and one dynamic standardized manual handling task, pre- and post-shift, by 40 physiotherapists. Participants also rated their pain and fatigue on a visual analogue scale (VAS). Statistical analysis utilised paired samples Student's t tests.

RESULTS

Significant differences were seen in the EMG activity in the quadriceps during the static task only. No significant differences were seen for any of the kinematic variables. Significant differences in fatigue (p < 0.005) were seen between the pre- and post-shift sessions. Notably, there were significant differences in pain between the pre- and post-shift sessions in the static (p < 0.01) and dynamic tasks (p < 0.05). This increase in pain was at a level which impacted on function.

CONCLUSION

Whilst significant variations in task performance were not observed, our findings indicate that physiotherapists frequently experience task-related pain towards the end of their shift. Contemporary research indicates that frequent transient low back pain may transition to a chronic disabling condition, as such we posit that the effects of intra-shift pain, and its causative factors, should be more widely considered in a 'whole-of-job' approach to mitigating risk in this demographic.

Visualization of the epimysium and fascia thoracolumbalis at the lumbar spine using MRI

BACKGROUND

The fascia thoracolumbalis (FTL) is an important component for stabilization and motion control of the lumbar spine. It coordinates the traction forces of the autochthonous muscles of the back (AM) and connects them to the muscles of the abdominal wall, shoulder, and buttocks.

OBJECTIVES

The aim of our study was to describe the assessment of the normal FTL and epimysium of the AM in MRI and to identify patterns associated with pathological changes in the lumbar spine.

MATERIAL AND METHODS

A total of 33 patients were retrospectively evaluated: 15 patients had no pathology at the lumbar spine; six patients had previous hemilaminectomy, three had spondylodesis, two had ventrolisthesis, and seven had scoliosis. The thickness of the FTL and EM was measured, and the adhesion of both structures was assessed.

RESULTS

The fascial thickness at the levels of the lumbar vertebral bodies LVB 3 was 1.8, of LVB 4 it was 2.0, of LVB 5 it was 2.1, and at the sacral vertebra SVB 1 it was 1.8 mm. Fascial adhesions together with thickening of the EM occurred at the level of LVB 4 in 36% of the cases independently of the underlying disorder. Only thickening of the EM was seen in 48% of cases at the level of SVB 1. By contrast, adhesion of the FTL without epimysial changes occurred in 36% of cases at the level of LVB 3.

CONCLUSION

Thickening and adhesions at the EM and FTL occurred both postoperatively and in the case of scoliosis. Furthermore, lipomatous and muscular herniation could be detected in the FTL postoperatively. Epimysial and fascial alterations may be imaging manifestations of chronic myofascial back pain and should be included in radiological assessments.

Spine MRI: A Review of Commonly Encountered Emergent Conditions

Over the last 2 decades, the proliferation of magnetic resonance imaging (MRI) availability and continuous improvements in acquisition speeds have led to significantly increased MRI utilization across the health care system, and MRI studies are increasingly ordered in the emergent setting. Depending on the clinical presentation, MRI can yield vital diagnostic information not detectable with other imaging modalities. The aim of this text is to report on the up-to-date indications for MRI of the spine in the ED, and review the various MRI appearances of commonly encountered acute spine pathology, including traumatic injuries, acute non traumatic myelopathy, infection, neoplasia, degenerative disc disease, and postoperative complications. Imaging review will focus on the aspects of the disease process that are not readily resolved with other modalities.

DECT in Detection of Vertebral Fracture-associated Bone Marrow Edema: A Systematic Review and Meta-Analysis with Emphasis on Technical and Imaging Interpretation Parameters

Background Dual-energy CT (DECT) shows promising performance in detecting bone marrow edema (BME) associated with vertebral body fractures. However, the optimal technical and image interpretation parameters are not well described. Purpose To conduct a systematic review and meta-analysis to determine the diagnostic performance of DECT in detecting BME associated with vertebral fractures (VFs), using different technical and image interpretation parameters, compared with MRI as the reference standard. Materials and Methods A systematic literature search was performed on July 9, 2020, to identify studies evaluating DECT performance for in vivo detection of vertebral BME. A random-effects model was used to derive estimates of the diagnostic accuracy parameters of DECT. The impact of relevant covariates in technical, image interpretation, and study design parameters on the diagnostic performance of DECT was investigated using subgroup analyses. Results Seventeen studies (with 742 of 2468 vertebrae with BME at MRI) met inclusion criteria. Pooled estimates of sensitivity, specificity, and area under the curve of DECT for vertebral body BME were 89% (95% CI: 84%, 92%), 96% (95% CI: 92%, 98%), and 96% (95% CI: 94%, 97%), respectively. Single-source consecutive scanning showed poor specificity (78%) compared with the dual-source technique (98%, P < .001). Specificity was higher using bone and soft-tissue kernels (98%) compared with using only soft-tissue kernels (90%, P = .001). Qualitative assessment had a better specificity (97%) versus quantitative assessment (90%) of DECT images (P = .01). Experienced readers showed considerably higher specificity (96%) compared with trainees (79%, P = .01). DECT sensitivity improved using a higher difference between low- and high-energy spectra (90% vs 83%, P = .04). Conclusion Given its high specificity, the detection of vertebral bone marrow edema with dual-energy CT (DECT) associated with vertebral fracture may obviate confirmatory MRI in an emergency setting. Technical parameters, such as the dual-source technique, both bone and soft-tissue kernels, and qualitative assessment by experienced readers, can ensure the high specificity of DECT. © RSNA, 2021 Online supplemental material is available for this article.