Table 1 Overview of included studies on machine learning and LBP.

From: Artificial intelligence to improve back pain outcomes and lessons learnt from clinical classification approaches: three systematic reviews

Study

Year

N

N

LBP

N

CON

Type LBP

AI/ML techniques

Utilised for

Summary

Inputs

Train/Test

Sen

Sp

Acc

AUC

Conclusions

Case−control

 Abdullah et al.49

2018

310

210

100

Unclear

K-Nearest Neighbour, Principal Component Analysis, Random Forest

Classification

To predict spinal abnormalities using machine-learning techniques

Pelvic incidence, pelvic tilt, lumbar lordosis angle, sacral slope, pelvic radius, degree spondylolisthesis, pelvic slope, direct tilt, thoracic slope, cervical tilt, sacrum angle and scoliosis slope

Yes

0.85

Authors concluded that the KNN classifier outperformed the RF classifier.

 Al Imran et al.50

2020

310

210

100

Unclear

Random Forest, K-Nearest Neighbour, Support Vector Machine

Classification

Enhancing classification performance in low-back pain symptoms

Pelvic incidence, pelvic tilt, lumbar lordosis angle, sacral slope, pelvic radius, degree spondylolisthesis, pelvic slope, direct tilt, thoracic slope, cervical tilt, sacrum angle and scoliosis slope

Yes

0.92

Authors concluded that the application of the genetic algorithm-based feature selection approach can improve classification accuracy.

 Ashouri et al.20

2017

52

52

28

Chronic

Support Vector Machine

Classification

Spinal 3D kinematic assessment to classify individuals with chronic low-back pain using machine learning

Five trunk flexion and extension parameters

Yes

1.00

1.00

1.00

Authors concluded that quantitative techniques provide clinicians and practitioners with improved discriminating means for predicting and diagnosing low-back disorders.

 Bishop et al.23

1997

183

183

80

Unclear

Artificial Neural Network

Classification

Classifying low-back pain from dynamic motion characteristics

Trunk range of motion and movement velocity

Yes

0.86

Authors concluded a neural network based on kinematic data is an excellent predictive model for the classification of low-back pain.

 Bounds et al.53

1990

200

200

0

Other

Multi-Layer Perception, K-Nearest Neighbor

Classification

A comparison of neural networks to other pattern recognition approaches for low-back pain

NR

Yes

0.95

Authors concluded that MLP and RBF networks outperform clinicians.

 Caza-Szoka et al.54

2015

65

43

22

Chronic

Naïve Bayes

Classification

Bayesian learning for electromyography in chronic low-back pain

Electromyography data

Yes

0.70

Authors concluded this paper outlined the advantage of Naïve Bayesian classification models.

 Caza-Szoka et al.24

2016

24

24

12

Chronic

Artificial Neural Network

Classification

Electromyography array for predicting chronic low-back pain

Electromyography of the paraspinal muscles

Yes

0.80

Authors concluded that a nonlinear analysis can be used for CLBP detection.

 Chan et al.55

2013

40

20

20

Chronic

Artificial Neural Network, Artificial Neural Network, Multi-Layer Perception, Decision Tree

Classification

A smart phone-based gait assessment to identify people with low-back pain

Gait features

No

0.88

Authors concluded it is feasible to develop a mobile-based tele-care system for monitoring gait.

 Darvishi et al.25

2017

160

160

92

Unclear

Artificial Neural Network, Logistic Regression, K-Nearest Neighbor

Classification

Prediction of low-back pain severity in industrial workers based on personal, psychological, and occupational factors

Age, gender, body mass index, smoking status, alcohol status, family history, SMWL, job stress, job satisfaction, job security, social relations, force, repetition, posture, and career length

Yes

0.92

Authors concluded that a neural network prediction model was more accurate than regression methods.

 Du et al.57

2018

171

88

83

Chronic

Support Vector Machine

Classification

Using surface electromyography to detect chronic low-back pain

Electromyography data

Yes

0.98

Authors concluded the models recognised chronic low-back pain with high accuracy.

 Hu et al.28

2018

44

44

22

Chronic

Artificial Neural Network

Classification

Deep learning to identify low-back pain during static standing

Angular rotation, linear translation and centre of pressure measures

Yes

0.97

0.99

Authors concluded that the deep learning neural networks could be used to accurately differentiate LBP populations from healthy controls using static balance performance.

 Hung et al.29

2014

52

52

26

Chronic

Artificial Neural Network, Principal Component Analysis

Classification

Electromyography to classify low-back pain from lifting capacity evaluation

Erector spinae muscle activity (including 30 and 50% loading) during lifting tasks

No

0.90

0.88

0.89

0.93

Authors concluded that features with different loadings (including 30 and 50% loading) during lifting can distinguish healthy and back pain subjects.

 Jin-Heeku et al.32

2018

1510

1510

883

Unclear

Support Vector Machine

Classification

Analysis of sitting posture predicting low-back pain

Data from pressure sensors to assess sitting posture

Yes

1.00

1.00

1.00

Authors concluded that a support vector machine can classify individuals with CLBP.

 LeDuff et al.34

2001

59

59

NR

Unclear

Artificial Neural Network

Classification

Data mining medical records to understand low-back pain treatment pathways

Number of contacts with the different kinds of health professionals, medicines and total costs

Yes

0.91

No specific conclusions.

 Melo Riveros et al.40

2019

310

310

210

Other

Artificial Neural Network, K-Means Clustering, Self-Organising Map

Classification

Diagnosing spinal pathology from low-back positional characteristics

Pelvic incidence, pelvic inclination, angle of lordosis, sacral slope, pelvic radius and degree of spondylolisthesis

Yes

0.79

0.92

0.83

Authors concluded the solution obtained with self-organising maps provides better results with respect to the solution obtained with K-means.

 Oliver et al.41

1995

98

98

62

Other

Artificial Neural Network

Classification

Electromyography to predict low-back pain.

Electromyography data (power spectra)

Yes

0.82

0.91

0.92

Authors concluded that the electromyography signals and ML techniques may be useful for identifying back pain patients.

 Oliver et al.42

1996

60

60

27

Chronic

Artificial Neural Network

Classification

Electromyography to predict low-back pain

Electromyography data (power spectra)

Yes

0.80

0.79

Authors stated that artificial intelligence neural networks appear to be a useful method of differentiating paraspinal power spectra in back pain sufferers.

 Olugbade et al.62

2015

53

23

30

Chronic

Support Vector Machine

Classification

Pain level prediction and classification using kinematics and muscle activity

Trunk flexion kinematics and EMG, sit-to-stand kinematics and EMG and depression

Yes

0.94

Authors concluded the model had very good performance due to thorough analyses.

 Parsaeian et al.44

2012

34,589

34,589

7286

Unclear

Artificial Neural Network

Classification

Predicting low-back pain based on lifestyle and psychosocial characteristics

Age, sex, education level, urban versus rural, smoker versus non-smoker, strenuous versus non-strenuous working conditions, BMI, mental health disorders and marital status

Yes

0.75

Authors concluded that an artificial neural network approach yielded better performance than logistic regression but that the difference would not be clinically significant.

 Sandag et al.63

2018

310

210

100

Unclear

K-Nearest Neighbour, Logistic Regression, Naïve Bayes, Random Forest, Decision Tree

Classification

Classification of low-back pain using K-Nearest Neighbour algorithm

Pelvic incidence, pelvic tilt, lumbar lordosis angle, sacral slope, pelvic radius, degree spondylolisthesis, pelvic slope, direct tilt, thoracic slope, cervical tilt, sacrum angle and scoliosis slope

Yes

0.92

Authors concluded K-Nearest Neighbour approaches could be used to help further classify low-back pain individuals.

 Silva et al.47

2015

12

12

5

Unclear

Support Vector Machine

Classification

Identifying low-back pain in golfers off muscle activity and swing kinematics

Electromyography during golf swing and kinematic variables of golf swing

Yes

1.00

Authors concluded that low-back pain golfers showed different neuromuscular coordination strategies when compared with asymptomatic golfers.

 Ung et al.64

2014

94

47

47

Chronic

Support Vector Machine

Classification

Multivariate classification of chronic low-back pain on structural MRI data

Structural brain MRI data

Yes

0.76

Authors concluded support vector machines could classify chronic low-back pain based on grey matter changes.

 Karabulut et al.58

2014

310

210

100

Unclear

Synthetic Minority Technique, Logistic Model Tree

Diagnosis

Automated predictions of vertebral pathologies with a logistic model tree

Pelvic incidence, pelvic tilt, lumbar lordosis angle, sacral slope, pelvic radius, degree spondylolisthesis, pelvic slope, direct tilt, thoracic slope, cervical tilt, sacrum angle and scoliosis slope

Yes

0.90

Authors concluded that the machine-learning techniques reasonably accurate classification.

 Mathew et al.38

1988

200

200

200

Other

Fuzzy Logic

Diagnosis

Classifying nerve root compression, simple low-back pain, spinal pathology and abnormal illness behaviour.

Age, sex, site of pain, duration of pain, type of onset, relationship to physical activity and movement, neurological symptoms, inappropriate symptoms, red- and yellow-flags in history and spinal deformity

Yes

0.90

Authors stated that the AI techniques can be used for the differential diagnosis of low-back disorders and can outperform clinicians.

 Mathew et al.61

1989

150

150

0

Surgery

Computer Diagnostic System

Diagnosis

Prediction of operative findings in low-back surgery

Age, sex, site of pain, duration of pain, type of onset, relationship to physical activity and movement, neurological symptoms, inappropriate symptoms, red- and yellow-flags in history and spinal deformity

Yes

0.92

Authors concluded that this computer system has the potential to facilitate assessment on a large number of patients.

 Vaughn et al.65

1998

198

198

0

Other

Multi-Layer Perception

Diagnosis

Knowledge extraction from a multilayer network for low-back classification

Demographic data, present and past symptoms, pain description/behaviour, finding from physical examination (lumbar spinal movements, tension tests, neurological tests), Oswestry Disability Index, Zung depression index, modified somatic perception questionnaire, the distress and risk assessment method

Yes

0.96

Authors concluded that future work should seek to automatically endure a valid rule for each input case to enhance the network.

 Vaughn et al.66

2001

196

196

0

Other

Multi-Layer Perception

Diagnosis

MLP network for the classification of low-back pain

Demographic data, present and past symptoms, pain description/behaviour, finding from physical examination (lumbar spinal movements, tension tests, neurological tests), Oswestry Disability Index, Zung depression index, modified somatic perception questionnaire, the distress and risk assessment method

Yes

0.77

Authors concluded a full explanation facility interprets the output on a case-by-case basis.

 Vaughn et al.48

2001

198

198

198

Other

Artificial Neural Network

Diagnosis

Classifying nerve root compression, simple low-back pain, spinal pathology and abnormal illness behaviour

Demographic data, present and past symptoms, pain description/behaviour, finding from physical examination (lumbar spinal movements, tension tests, neurological tests), Oswestry Disability Index, Zung depression index, modified somatic perception questionnaire and the distress and risk assessment method

Yes

0.82

Authors stated that application of the method leads to the discovery of a number of mis-diagnosed training and test cases and to the development of a more optimal low-back-pain MLP network.

 Sari et al.45

2012

169

169

110

Unclear

Artificial Neural Network, Fuzzy Inference System

Other

Predicting low-back pain intensity based on pain intensity and skin resistance

Skin resistance and pain intensity

Yes

Authors stated that their designed systems are effective to predict the pain intensity level objectively.

Cohort

 Magnusson et al.37

1998

27

27

0

Chronic

Artificial Neural Network

Classification

Range of motion and motion patterns following rehabilitation in low-back pain

Trunk motion data from eight motion tests

Yes

0.78

Authors stated that a neural network based on kinematic variables is an excellent model for classification of low-back-pain dysfunction.

 Azimi et al.21

2014

168

168

0

Spinal Stenosis

Artificial Neural Network

Prognosis

Predicting surgical satisfaction for lumbar spinal canal stenosis with artificial neural networks

Age, pain intensity, stenosis ratio, walking distance, Japanese Orthopaedic Association score for assessing LBP, and Neurogenic Claudication Outcome Score

Yes

0.41

0.97

0.81

Authors concluded that artificial neural network approach more accurate in predicting 2-year post-surgical satisfaction than a logistic regression model.

 Azimi et al.22

2015

402

402

0

Recurrent

Artificial Neural Network

Prognosis

Predicting recurrent lumbar disc herniation with artificial neural networks

Age, sex, duration of symptoms, smoking status, recurrent LDH, level of herniation, type of herniation, sports activity, occupational lifting, occupational driving, duration of symptoms, visual analogue scale, the Zung Depression Scale, and the Japanese Orthopaedic Association Score

Yes

0.46

0.94

0.84

Authors concluded that artificial neural networks can be used to predict recurrence of lumbar disc herniation.

 Barons et al.52

2013

701

701

0

Unclear

Artificial Neural Network, Latent Class Analysis, Logistic Regression

Prognosis

Determining who benefits from cognitive behavioural therapy

RMDQ, FABQ, PSE, SF-12, HADS

No

0.61

Authors concluded that artificial neural networks would be the best candidate to support treatment allocation.

 Hallner et al.27

2004

71

71

0

Acute

Artificial Neural Network

Prognosis

Identifying individuals at risk of chronic low-back pain based on yellow-flags

Pain intensity at the beginning of hospitalisation, Beck Depression Inventory and Kiel Pain Inventory

Yes

0.73

0.97

0.83

Authors concluded that this model could contribute to the early detection of risk factors for patients with acute low-back pain, and could assist with avoiding chronicity.

 Jarvik et al.30

2018

4665

4665

0

Acute

LASSO Model

Prognosis

Predicting recovery from acute low-back pain in older adults

Age, gender, race, ethnicity, education, employment status, marital status, smoking status, the duration of current episode of back or leg pain, back-related claim or lawsuit, patient confidence that their back or leg pain would be completely gone or much better in 3 months, baseline pain-related characteristics, baseline psychological distress, baseline falls, BMI, comorbidity score, baseline diagnosis, spine-related interventions and opioid prescriptions

Yes

0.75

Authors concluded that baseline patient factors were more important than early interventions in explaining disability and pain after 2 years.

 Jiang et al.31

2017

78

30

48

Chronic

Support Vector Machine

Prognosis

Electromyography for prediction of recovery following functional restoration

Electromyography during left lateral bending, right lateral bending, left turning, right turning

Yes

1.00

0.94

0.97

0.89

Authors stated that the tools can be used to identify patients who will respond to functional restoration rehabilitation.

 Shamim et al.46

2009

501

501

0

Surgery

Fuzzy Inference System

Prognosis

Prediction of poor outcomes following lumbar disc surgery

Sex, BMI, occupation, marital status, use of oral corticosteroids, multilevel disease, epidural steroid injection, duration of symptoms, duration of non-operative treatment, extent of changes on MRI, previous spine surgery, emergency versus elective surgery, operative time, intraoperative complications, operating surgeon and post-op complications

No

0.88

0.86

Authors concluded a fuzzy inference system is a sensitive method of predicting patients who will fail to improve with surgical intervention.

Other

 Kadhim et al.33

2018

10

10

0

Unclear

Fuzzy Inference System

Classification

A decision support system for back pain diagnosis

Sex, height, weight, age and a series of clinical symptoms

No

0.84

Author stated that the proposed system can be used by domain experts (physicians) to help enhance decision-making.

 Lee et al.19

2019

53

53

0

Chronic

Support Vector Machine

Classification

Prediction of clinical pain intensity from functional connectivity and autonomic states

Functional connectivity and heart rate variability

Yes

0.92

0.97

Authors concluded that a machine-learning approach model identifies putative biomarkers for clinical pain intensity.

 Lin et al.60

2006

180

180

0

Unclear

Naïve Bayes

Diagnosis

A decision support system for low-back pain diagnosis

Gender, age, current pain symptoms, clinical pain history, pregnancy history, number and tingling

No

0.73

Authors concluded the system provides an easy-to-follow framework for low-back pain.

 Andrei et al.51

2015

260

260

0

Other

Fuzzy Inference System

Prognosis

Computer-aided patient evaluation of low-back pathology

Pain, calories, flexion, extension, rotation and lateral flexion range of motion

No

0.98

Authors concluded a complex fuzzy system is essential for lumbar spine pathology.

 Li et al.59

2017

100

100

0

Unclear

Artificial Neural Network, K-Nearest Neighbor, Fuzzy Inference System

Prognosis

Probabilistic Fuzzy classification for Stochastic data

Pain area, height and width of pain area and ratio

No

NR

Authors concluded more information can be extracted from limited samples using a PFC approach.

 Dickey et al.56

2000

9

9

0

Chronic

Artificial Neural Network

Other

Relationship between pain and spinal motion characteristics in low-back pain

32 spinal motion parameters

No

0.99

Authors concluded they observed clear patterns of segmental spinal motion in low-back pain.

 Liszka-Hackzell et al.35

2002

40

40

0

Other

Artificial Neural Network

Other

Categorising individuals with low-back pain based on self-report and activity data

Unclear

Yes

Authors stated that that neural network techniques can be applied effectively to categorising patients with acute and chronic low-back pain.

 Liszka-Hackzell et al.36

2005

18

18

0

Chronic

Artificial Neural Network

Other

Analysis of night-time activity and daytime pain in chronic low-back pain

Measures of sleep quality through actigraphy

Yes

Authors concluded that daytime pain levels are not correlated with sleep the night before, nor with the night following.

 Meier et al.39

2018

20

20

0

Chronic

Multivariate Patten Analysis

Other

Predicting neural adaptions based on psychosocial constructs

Bilateral fear-related brain regions including the amygdala, hippocampus, thalamus, anterior cingulate, insula, and medial prefrontal, and orbitofrontal cortices

Yes

Authors stated the approach might ultimately help to further understand and dissect psychological pain-related fear.

 Gal et al.26

2015

15

15

0

Unclear

Fuzzy Inference System

Treatment allocation

Computer-assisted prediction of low-back pain treatment

Sex, age, disability level, daily activity expressed in calories and trunk mobility measures

No

Authors concluded the system has the ability to identify the correct treatment and can ensure the quality of the treatment.

 Oude et al.43

2018

45

45

0

Unclear

Boosted Tree, Decision Tree, Random Forest

Treatment allocation

To determine if self-referral is possible in individuals with low-back pain

Age, well-being index, duration of pain, use of analgesics, history of trauma, use of corticosteroids, presence of specific serious disease, weight loss in past month, constant pain, night-time pain, pain with lifting/sneezing/coughing, radiating pain, reduced muscle strength, cauda equina symptoms, referral preference

Yes

0.72

Authors stated that the study showed possibilities of using ML to support patients with LBP in their self-referral process to primary care.

  1. Acc accuracy, AI artificial intelligence, AUC area under the curve, — not reported, ML machine learning, Other study design not case control or cohort, Sen sensitivity, Sp specificity.