Virtual Reality–Based Training in Chronic Low Back Pain: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Background

Low back pain is one of the most prevalent pain conditions worldwide. Virtual reality–based training has been used for low back pain as a new treatment strategy. Present evidence indicated that the effectiveness of virtual reality–based training for people with chronic low back pain is inconclusive.

Objective

This study conducted a meta-analysis to evaluate the immediate- and short-term effects of virtual reality–based training on pain, pain-related fear, and disability in people with chronic low back pain.

Methods

We searched the PubMed, Embase, Web of Science, PEDro, CENTRAL, and CINAHL databases from inception until January 2024. Only randomized controlled trials assessing the effects of virtual reality–based training on individuals with chronic low back pain were selected. The outcomes were focused on pain, pain-related fear measured by the Tampa Scale of Kinesiophobia, and disability measured by the Oswestry Disability Index. The immediate term was defined as the immediate period after intervention, and the short term was defined as 3 to 6 months after intervention. The Cochrane Risk of Bias tool and the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach were used to evaluate the quality of the methodology and evidence, respectively.

Results

In total, 20 randomized controlled trials involving 1059 patients were eligible for analysis. Virtual reality–based training showed significant improvements in pain (mean difference [MD] –1.43; 95% CI –1.86 to –1.00; I²=95%; P<.001), pain-related fear using the Tampa Scale of Kinesiophobia (MD –5.46; 95% CI –9.40 to 1.52; I²=90%; P=.007), and disability using the Oswestry Disability Index (MD –11.50; 95% CI –20.00 to –3.01; I²=95%; P=.008) in individuals with chronic low back pain immediately after interventions. However, there were no significant differences observed in pain (P=.16), pain-related fear (P=.10), and disability (P=.43) in the short term.

Conclusions

These findings indicated that virtual reality–based training can be used effectively for individuals with chronic low back pain in the immediate term, especially to reduce pain, alleviate pain-related fear, and improve disability. However, the short-term benefits need more high-quality trials to be demonstrated.

Trial Registration

PROSPERO CRD42021292633; http://tinyurl.com/25mydxpz

Introduction

Low back pain is a common musculoskeletal symptom influenced by complex interactions among biological, psychological, and social factors [1-3]. With more than 568 million people experiencing low back pain globally, it has become the leading cause of years lived with disability worldwide [4,5]. Low back pain is defined by the location of pain, typically between the lower rib margins and the buttock creases [6]. Once the symptom persists for more than 3 months, it can be considered as chronic low back pain. Chronic low back pain may be accompanied by fear avoidance and dysfunction. Research has suggested that individuals who hold negative beliefs about their pain or their condition may experience an exaggerated fear of pain and the potential negative consequences of their symptoms. This fear can lead to a cycle of catastrophizing thoughts, pain-related fear, and avoidance of movements that they perceive as potentially painful or harmful [7]. Furthermore, fear avoidance and catastrophizing thoughts are considered catalysts for chronicity, resulting in prolonged recovery and increased disability rates [8].

Given the impaired physical function, quality of life, and even social participation from chronic low back pain [9], it is a global priority to establish an effective treatment [6,10,11]. Multicomponent exercises are frequently prescribed by physicians for chronic low back pain, as recommended by clinical practice guidelines and established by randomized controlled trials (RCTs) [12-16]. Exercises encompass a diverse set of components including specific activities, postures, or movements (or all) [17]. It is reported that exercises may benefit patients with chronic low back pain by improving muscle strength and movement and enhancing postural musculature, stability, and coordination, or a combination of these factors [18]. Among the various exercises available, virtual reality–based training is becoming increasingly popular for the treatment of chronic low back pain [19-22]. It refers to digital training via computer-generated realities implemented with stereoscopic displays [23,24]. In addition, virtual reality–based training has been shown to reduce the focus on pain by dividing attention to tasks [25,26] and increase the motivation of movement through progressive achievement [27-29].

Two systematic reviews suggested that virtual reality–based training had a positive effect on improving pain intensity [30] and fear avoidance [31] in people with low back pain, while other systematic reviews indicated that the effectiveness of virtual reality–based training was inconclusive [32,33]. To our knowledge, evidence on the immediate-, short-, and long-term benefits of virtual reality–based training in patients with chronic low back pain does not exist as well. The evidence on the potential effectiveness of virtual reality–based training for chronic low back pain is still controversial and deficient. Therefore, we conducted this systematic review and meta-analysis to evaluate the immediate-term and short-term efficacy of virtual reality–based training for chronic low back pain.

Methods

Design

This systematic review and meta-analysis followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) [34] and PRISMA 2020 guidelines (Multimedia Appendix 1) [35] and was performed following a protocol registered in PROSPERO (CRD42021292633).

Search Strategy

Two reviewers (RL and YL) independently searched the PubMed, Embase, Web of Science, PEDro, CENTRAL, and CINAHL databases from inception until January 2024. Low back pain and virtual reality were searched as keywords. The full search strategy is described in Multimedia Appendix 2. The bibliographic references of the included studies and previous systematic reviews were also checked to identify additional trials.

Study Selection

Studies concerning the effects of virtual reality involving individuals with low back pain were included in this systematic review. The inclusion criteria were as follows: (1) RCTs of parallel groups, (2) participants experiencing chronic low back pain, (3) virtual reality as intervention, (4) studies assessed clinical outcomes (eg, pain, pain-related fear, or disability), and (5) duration of intervention ≥8 sessions. The exclusion criteria were as follows: (1) reviews, case reports, and conference abstracts; (2) studies without enough information for data analysis; and (3) studies not written in English. The detailed inclusion and exclusion criteria are shown in Textbox 1.

The inclusion and exclusion criteria.

Inclusion criteria

• Paper type: randomized controlled trials of parallel groups

• Study subjects: participants with chronic low back pain (3 months or more)

• Interventions: virtual reality–based training as intervention alone or in combination with physical therapy, irregular of virtual reality devices; the duration of intervention is ≥8 sessions

• Outcomes: at least 1 of the following outcome measurements: pain (Visual Analog Scale, Numerical Rating Scale, and Defense and Veterans Pain Rating Scale), pain-related fear (Tampa Scale of Kinesiophobia), or disability (Oswestry Disability Index)

• Language: written in English

Exclusion criteria

• Paper type: reviews, case reports, and conference abstracts

• Study subjects: participants with other pain or low back pain lasting for less than 3 months

• Interventions: no interventions involved virtual reality

• Outcomes: without the required outcomes or no available data and not enough information for analysis

• Language: non-English publications

Outcome Measures

The outcomes were focused on pain, pain-related fear, and disability. The pain intensity was measured by the Visual Analog Scale, Numerical Rating Scale, and Defense and Veterans Pain Rating Scale, which have demonstrated strong validity and reliability in clinical and research settings [36-39]. The pain-related fear was measured by the Tampa Scale of Kinesiophobia, which is frequently used in patients with back pain [40,41]. As for the functional disability, the Oswestry Disability Index (ODI) was used [42].

Data Extraction

Two reviewers (RL and YL) independently extracted the main information for the included studies using a standard extraction spreadsheet (Microsoft Excel, Microsoft Corp). A third reviewer (YK) was consulted if the initial reviewers (RL and YL) disagreed. The detailed characteristics of the selected studies were summarized, which included study characteristics (author, year of publication, country, sample size, and follow-up points), population characteristics (gender, age, and pain duration), intervention characteristics (type, frequency, and duration), and outcome measurements (pain, pain-related fear, and disability).

Quality Assessment

The quality of RCTs was assessed using the Cochrane Risk of Bias tool [43], which consists of 5 domains and an overall judgment. The 5 domains include randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of the reported result. Based on the answers to a series of signaling questions, the judgment options in each domain consist of “low risk of bias,” “some concerns,” and “high risk of bias.” Two independent researchers (RL and HL) assessed the quality of each eligible study. Disagreements in the data were settled by consensus.

We used the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach to assess the quality of evidence, which is rated as high, moderate, low, and very low [44]. The quality of RCTs is initially considered high and then downgraded based on risk of bias, imprecision, inconsistency, indirectness, and publication bias [45-49].

Statistical Analysis

This meta-analysis was conducted using Review Manager (version 5.30; Cochrane Collaboration), and all extracted data were input and checked by the reviewers (RL, YL, and YK). Mean differences (MDs) were calculated with the 95% CIs using the inverse variance method, when the outcomes were evaluated with the same scale. The chi-square test and inconsistency (I²) were used to calculate statistical heterogeneity. The random effect model was used when I²>50%; otherwise, the fixed-effect model was used. Statistical differences by meta-analysis were identified as P<.05. Furthermore, the minimal clinically important difference (MCID) was taken into consideration in this study, and the standard was established according to a previous report.

Subgroup analyses comparing the efficacy of virtual reality on pain, pain-related fear, and disability were performed for immediate-term and short-term outcomes separately. The immediate term was defined as the immediate period after intervention, and the short term was defined as 3 to 6 months after intervention.

Results

Study Selection and Characteristics

The initial search procedure yielded 583 records in total, 294 of which were removed due to duplication. After the screening process, 20 studies were selected for this systematic review and meta-analysis (Figure 1). The 20 papers included 1059 individuals diagnosed with chronic low back pain. The characteristics (sample size, gender, interventions, exposures, and outcome measurements) of the involved studies were summarized (Table 1). All studies had an RCT design: 7 used a 3-arm parallel-group design [21,50-55], and 1 used a 4-arm parallel-group design [56]. Of the included papers, 4 studies involved only female patients [20,22,57,58], and 6 studies involved only male patients [52-56,59].

Figure 1.

Flowchart showing the study selection process. RCT: randomized controlled trial.

Table 1.

Characteristics of the included studies.

Study (year)	Country	Sample size	Gender	Mean age (years)	Pain duration (months)	Intervention	Exposure	Outcome measures	Follow-up points
Afzal et al (2022) [19]	Pakistan	Expa: 42 Conb: 42	Male: 28 Female: 56	Exp: 38.2 Con: 37.5	—c	Exp: Virtual reality–based exercises via kinetic exergames+physical therapy Con: Back strengthening exercises+physical therapy	12 sessions; 3 times per week	VASd; ODIe	4 weeks
Eccleston et al (2022) [50]	Finland	Exp1: 14 Exp2: 17 Con: 11	Male: 5 Female: 37	Exp1: 55.14 Exp2: 52.76 Con: 57.09	>6	Exp1: Virtual reality–based cognitive behavioral intervention via Oculus Quest and Touch virtual reality headset and handheld controllers Exp2: Viewed text-based cognitive behavioral intervention via Oculus Quest and Touch virtual reality headset Con: Standard care	30 sessions; 5 times per week; 15-60 minutes per session	NRSf; ODI; PROMISg 6b; TSKh; pain medications; EuroQoL-5D-5Li; adverse events; PGICj; Game Experience Questionnaire	9 weeks, 5 months
Garcia et al (2021) [60]	United States	Exp: 94 Con: 94	Male: 43 Female: 144	Exp: 52.1 Con: 51.3	≥6	Exp: Virtual reality–based cognitive behavioral therapy via Pico G2 4K head-mounted virtual reality device (3D visual displays) Con: Sham virtual reality–based cognitive behavioral therapy via Pico G2 4K head-mounted virtual reality device	56 sessions; 7 times per week; 2-16 minutes per session	DVPRSk; DVPRS-II; PSEQl-2; PGIC; PROMIS 6b and 6a; PCSm; CPAQ-8n	8 weeks, 3 months, 6 months
Groenveld et al (2023) [61]	Netherlands	Exp: 20 Con: 20	Male: 7 Female: 33	Exp: 51 Con: 52	Exp: 5 Con: 4	Exp: Virtual reality–based exercises via an Oculus Go head-mounted display Con: Daily life routines	60 sessions; 3 times per day; 10-30 minutes per session	SF-12o; VAS; PCS; HADSp; ODI; PCCLq; NEADLr; BPIs	4 weeks, 4 months
Kim et al (2014) [20]	South Korea	Exp: 15 Con: 15	Male: 0 Female: 30	Exp: 44.33 Con: 50.46	—	Exp: Virtual reality–based yoga program via Wii Fit activities Con: Trunk stabilizing exercise+physical therapy program	12 sessions; 3 times per week; 30 minutes per session	VAS; pressure algometry; ODI; RMDQt; FABQu	4 weeks
Kim et al (2020) [62]	South Korea	Exp: 24 Con: 24	Male: 26 Female: 22	Exp: 26.0 Con: 28.79	Exp: 58.22 Con: 101.55	Exp: Virtual reality–based simulated horseback riding Con: Stabilization exercise via suspension	16 sessions; 2 times per week; 46 minutes per session	NRS; ODI; RMDQ; FABQ	4 weeks, 8 weeks, 6 months
Li et al (2021) [51]	China	Exp1: 11 Exp2: 12 Con: 11	Male: 9 Female: 25	Exp1: 21.91 Exp2: 23.75 Con: 25.36	Exp1: 30.18 Exp2: 38.83 Con: 49.82	Exp1: Virtual reality–based Fruit Ninja game via Kinect Xbox 360+magnetic therapy Exp2: Ultrasound-guided abdominal drawing-in maneuver training+magnetic therapy Con: Conventional thermal magnetic therapy	10 sessions; 5 times per week; 30 minutes per session	VAS; ODI; sEMGv	2 weeks
Meinke et al (2022) [63]	Switzerland	Exp: 13 Con: 14	Male: 10 Female: 17	Exp: 40.14 Con: 40.85	—	Exp: Virtual reality–based exergame via 2 inertial measurement units Con: Daily life routines	9 sessions; 3 times per week; 20 minutes per session	NRS; TSK; RMDQ; WHOQOL-Brefw	3 weeks
Monteiro-Junior et al (2015) [57]	Brazil	Exp: 16 Con: 14	Male: 0 Female: 30	68	—	Exp: Virtual reality–based physical training via Nintendo Wii-motion and WBBx+core and strength training Con: Core and strength training	24 sessions; 3 times per week; 90 minutes per session	NRS; WBB; sit-to-stand test; POMSy	8 weeks
Nambi et al (2020) [54]	Saudi Arabia	Exp1: 15 Exp2: 15 Con: 15	Male: 45 Female: 0	Exp1: 21.25 Exp2: 20.23 Con: 20.78	Exp1: 4.1 Exp2: 4.1 Con: 4.3	Exp1: Virtual reality–based-balance training via Pro-Kin system PK 252 N Exp2: Balance training via Swiss ball Con: Conventional balance training via active isotonic and isometric exercise	20 sessions; 5 times per week; 30 minutes per session	VAS; player wellness; sprint performance; jump performance	4 weeks, 8 weeks, 6 months
Nambi et al (2021) [55]	Saudi Arabia	Exp1: 20 Exp2: 20 Con: 20	Male: 60 Female: 0	Exp1: 21.45 Exp2: 21.39 Con: 20.97	Exp1: 4.8 Exp2: 5.2 Con: 4.9	Exp1: Virtual reality training via firing game Exp2: Core stabilization training via therapeutic ball Con: Traditional active balance exercise	20 sessions; 5 times per week; 30 minutes per session	NRS; physical fitness index; sprint performance; jump performance	4 weeks, 8 weeks, 6 months
Nambi et al (2021) [53]	Saudi Arabia	Exp1: 18 Exp2: 18 Con: 18	Male: 54 Female: 0	Exp1: 22.3 Exp2: 21.4 Con: 21.9	Exp1: 5.4 Exp2: 5.3 Con: 5.5	Exp1: Virtual reality training+hot pack therapy+ultrasound Exp2: Isokinetic training+hot pack therapy+ultrasound Con: Conventional core training+hot pack therapy+ultrasound	20 sessions; 5 times per week; 30 minutes per session	VAS; TSK; blood serum level of stress hormones	4 weeks, 6 months
Nambi et al (2021) [52]	Saudi Arabia	Exp1: 20 Exp2: 20 Con: 20	Male: 60 Female: 0	Exp1: 23.2 Exp2: 22.8 Con: 23.3	Exp1: 5.8 Exp2: 5.2 Con: 5.4	Exp1: Virtual reality training+hot pack therapy+ultrasound Exp2: Isokinetic training+hot pack therapy+ultrasound Con: Conventional core training+hot pack therapy+ultrasound	20 sessions; 5 times per week; 30 minutes per session	VAS; TSK; blood serum level of stress hormones	4 weeks, 6 months
Oh et al (2014) [56]	South Korea	Exp1: 9 Exp2: 9 Exp3: 10 Con: 9	Male: 37 Female: 0	Exp1: 20.7 Exp2: 20.56 Exp3: 20.33 Con: 20.44	Exp1: 6.38 Exp2: 6.21 Exp3: 7.57 Con: 6.75	Exp1: Virtual reality training via horse simulator machine for 10 minutes Exp2: Virtual reality training via horse simulator machine for 20 minutes Exp3: Virtual reality training via horse simulator machine for 30 minutes Con: Daily life routines	40 sessions; 5 times per week; 15-35 minutes per session	VAS; body composition; isokinetic trunk and hip extension or flexion and hip abduction or adduction	8 weeks
Park et al (2013) [21]	South Korea	Exp1: 8 Exp2: 8 Con: 8	—	Exp1: 44.12 Exp2: 43.37 Con: 44.12	Exp1: 17.0 Exp2: 16.0 Con: 18.75	Exp1: Virtual reality–based training via Nintendo Wii program+physical therapy Exp2: Lumbar stabilization exercise+physical therapy Con: Physical therapy (eg, hot pack, interferential current therapy, and deep heat with ultrasound)	24 sessions; 3 times per week; 80 minutes per session	VAS; isometric lifting strength for back strength; 1-legged Stand Test for balance ability; RAND-36z; SF-36aa	8 weeks
Park et al (2020) [58]	South Korea	Exp: 40 Con: 40	Male: 0 Female: 80	Exp: 71.35 Con: 72.05	Exp: 23.61 Con: 22.10	Exp: Virtual reality–based training via equestrian simulator Con: Sitting on the equestrian simulator	36 sessions; 3 times per week; 30 minutes per session	VAS; ODI; body composition; isokinetic trunk extension and flexion; spinal alignment	12 weeks
Yalfani et al (2022) [22]	Japan	Exp: 13 Con: 12	Male: 0 Female: 25	Exp: 68 Con: 67.08	>6	Exp: Virtual reality–based training via Xbox Kinect headset Con: Daily life routines	24 sessions; 3 times per week; 30 minutes per session	VAS; SF-36; FRIab; BBSac	2 weeks
Yilmaz Yelvar et al (2017) [64]	Iran	Exp: 22 Con: 22	Male: 16 Female: 28	Exp: 46.27 Con: 52.81	Exp: 5.27 Con: 7.45	Exp: Virtual walking task via Vita Digital Productions+physical therapy Con: Physical therapy (eg, hot pack, TENSad, deep heat with ultrasound, and therapeutic exercises)	10 sessions; 5 times per week	VAS; TSK; ODI; Nottingham Health Profile; TUGae; 6MWTaf; single-leg balance test	2 weeks
Yoo et al (2014) [59]	South Korea	Exp: 24 Con: 23	Male: 47 Female: 0	Exp: 20.44 Con: 20.7	Exp: 9.41 Con: 8.35	Exp: Virtual reality–based training via horse simulator Con: Daily life routines	24 sessions; 3 times per week; 20-50 minutes per session	VAS; body composition; isokinetic trunk strength	8 weeks
Zadro et al (2019) [65]	Turkey	Exp: 30 Con: 30	Male: 29 Female: 31	Exp: 68.8 Con: 67.8	>3	Exp: Video game home-based exercise via Nintendo Wii U console Con: Daily life routines	24 sessions; 3 times per week; 60 minutes per session	NRS; TSK; PSEQ; 3-item questionnaire; Rapid Assessment of Physical Activity questionnaire; PSFSag; RMDQ; 16-item Falls Efficacy Scale-International Questionnaire	8 weeks

^aExp: experimental group.

^bCon: control group.

^cNot available.

^dVAS: Visual Analog Scale.

^eODI: Oswestry Disability Index.

^fNRS: Numerical Rating Scale.

^gPROMIS: Patient-Reported Outcomes Measurement Information System.

^hTSK: Tampa Scale of Kinesiophobia.

ⁱEuroQoL-5D-5L: European Quality of Life 5-dimension, 5-level scale.

^jPGIC: Patient’s Global Impression of Change.

^kDVPRS: Defense and Veterans Pain Rating Scale.

^lPSEQ: Pain Self-Efficacy Questionnaire.

^mPCS: Pain Catastrophizing Scale.

ⁿCPAQ-8: Chronic Pain Acceptance Questionnaire.

^oSF-12: 12-item Short-Form Health Survey.

^pHADS: Hospital Anxiety and Depression Scale.

^qPCCL: Pain Coping and Cognition List.

^rNEADL: Nottingham Extended Activities of Daily Living.

^sBPI: Brief Pain Inventory.

^tRMDQ: Roland Morris Disability Questionnaire.

^uFABQ: Fear Avoidance Beliefs Questionnaire.

^vsEMG: surface electromyography.

^wWHOQOL-Brief: World Health Organization Quality of Life Questionnaire-short version.

^xWBB: Wii Balance Board.

^yPOMS: Profile of Mood States.

^zRAND-36: RAND-36 Health Status Inventory.

^aaSF-36: 36-item Short-Form Health Survey.

^abFRI: Fall Risk Index.

^acBBS: Biodex Balance System.

^adTENS: transcutaneous electrical nerve stimulation.

^aeTUG: Timed Up and Go Test.

^af6MWT: 6-Minute Walk Test.

^agPSFS: Patient-Specific Functional Scale.

Risk of Bias

In total, 20 studies were considered as having some concerns in overall bias, 2 as having a high risk of bias [20,21], and 1 as having a low risk of bias [19] (Figure 2 [19-22,50-65]). Due to the nature and setting of the intervention, it was not possible to blind the patients or therapists delivering the intervention, leading to some concerns in the second domain (deviations from the intended intervention). There was a high risk of bias regarding the measurement of outcome because of insufficient information on blinded assessment [20,21]. Baseline between intervention groups had significant differences in 2 studies [64,65].

Figure 2.

Risk-of-bias graph and summary.

Outcomes

Pain

All studies investigated the efficacy of virtual reality on pain using the Visual Analog Scale, Numerical Rating Scale, and Defense and Veterans Pain Rating Scale on a scale from 0 to 10. In total, 19 RCTs provided available data that were pooled into a meta-analysis (Figure 3 [19-22,50-60,62-65]). There were statistically significant differences between virtual reality–based training and conventional treatments for pain reduction in the immediate term (MD –1.43; 95% CI –1.86 to –1.00; I²=95%; P<.001) but not in the short term (MD –0.57; 95% CI –1.36 to 0.22; I²=99%; P=.16). Both did not reach an MCID at the level of 2.5 [66,67].

Figure 3.

Forest plots for virtual reality–based training compared with controls in pain. IV: inverse variance.

Pain-Related Fear

In total, 6 studies investigated the efficacy of virtual reality–based training on pain-related fear using the Tampa Scale of Kinesiophobia (Figure 4 [50,52,53,63-65]). Virtual reality–based training showed significant improvements in individuals with chronic low back pain in the immediate term (MD –5.46; 95% CI –9.40 to –1.52; I²=90%; P=.007), while it did not show statistically significant differences in the short term (MD –5.66; 95% CI –12.34 to 1.01; I²=96%; P=.10). The difference in the immediate- and short-term performance was extremely close to an MCID at the level of 5.5 [68].

Figure 4.

Forest plots for virtual reality–based training compared with controls in pain-related fear. IV: inverse variance.

Disability

In total, 8 studies investigated the efficacy of virtual reality–based training on disability using the ODI (Figure 5 [19,20,50,51,58,61,62,64]). There were statistically significant differences between virtual reality–based training and conventional treatments in terms of the ODI in the immediate term (MD –11.50; 95% CI –20.00 to –3.01; I²=95%; P=.008) but not in the short term (MD –1.28; 95% CI –4.47 to 1.90; I²=0%; P=.43). Only the immediate-term outcome did reach an MCID at the level of 10 [66,69].

Figure 5.

Forest plots for virtual reality–based training compared with controls in disability. IV: inverse variance.

Quality of Evidence

The quality of evidence ranged from low to very low due to the risk of bias, imprecision, and inconsistency of included trials (Table 2). None were downgraded because of indirectness and publication bias.

Table 2.

Summary of the findings and level of certainty using GRADE (Grading of Recommendations, Assessment, Development and Evaluation).

Time point and outcomes			Risk of bias		Inconsistency		Indirectness		Imprecision		Publication bias		Participants, n		RCTa, n		Mean difference (95% CI)		Certainty
Immediate term
	Pain	Seriousb		Seriousc		Not serious		Not serious		Not serious		879		19		–1.43 (–1.86 to –1.00)		Low
	Pain-related fear	Seriousb		Seriousc		Not serious		Seriousd		Not serious		229		6		–5.46 (–9.40 to –1.52)		Very low
	Disability	Seriousb		Seriousc		Not serious		Seriousd		Not serious		377		8		–11.50 (–20.00 to –3.01)		Very low
Short term
	Pain-related fear	Seriousb		Seriousc		Not serious		Seriousd		Not serious		106		3		–5.66 (–12.34 to 1.01)		Very low
	Pain	Seriousb		Seriousc		Not serious		Seriousd		Not serious		393		7		–0.57 (–1.36 to 0.22)		Very low
	Disability	Seriousb		Not serious		Not serious		Seriousd		Not serious		96		3		–1.28 (–4.47 to 1.90)		Low

^aRCT: randomized controlled trial.

^bDowngrade due to the majority of trials rated as some concerns.

^cDowngrade due to I² statistics >50%.

^dDowngrade due to pooled sample sizes <400.

Discussion

Principal Findings

This systematic review and meta-analysis, based on 20 RCTs, aimed to assess the available evidence on the efficacy of virtual reality–based training for people with chronic low back pain. The findings indicated that virtual reality–based training appeared to be an effective method of improving pain, pain-related fear, and disability immediately after intervention. However, current evidence failed to support the effectiveness of virtual reality–based training in the short term.

Virtual reality–based training has demonstrated efficacy in pain reduction for people with chronic low back pain [30,70]. However, our pooled results showed only a statistically significant reduction in pain immediately after interventions but not in the short term, which is consistent with previous studies [71-73]. In this study, there were no clinically significant differences between the immediate- and short-term performance. This may be explained by the fact that the virtual reality environment contributes to distraction from pain-related information [74,75]. However, once they gradually return to routines, the attention bias to pain might develop more often than being immersed in a virtual reality environment. This is supported by the finding that patients with chronic pain may less easily distract from the pain [76,77] due to higher levels of attention bias to pain [78].

Pain-related fear can activate the avoidance of movement, leading to the progression of disability [1]. In this study, we found that virtual reality–based training was superior to improve pain-related fear immediately after interventions, which is consistent with the effect on disability for individuals with chronic low back pain. It is worth noting that fear avoidance limits the opportunity to attune expectations to actual experiences, leading to long-term disability [79]. Consequently, with the alleviation of pain-related fear, individuals with chronic low back pain may be willing to pursue a positive experience, which is helpful to increase the level of physical activity. Although the large difference in the efficacy on pain-related fear in the short term indicated clinically important results but not statistically significant results, it should be interpreted cautiously due to the very low quality of evidence. Furthermore, the efficacy of virtual reality–based training on disability in the short term is also with low evidence. More high-quality RCTs are urgently needed for future research.

Strengths and Limitations

This systematic review and meta-analysis conducted a thorough screening and search strategy in 6 important databases. Additionally, this study focused on RCTs to reinforce the evidence of pooled results. We also used the Cochrane Risk of Bias tool and the GRADE approach to rate the quality of the included studies and evidence, respectively. However, the potential limitations in this study need to be mentioned. First, high heterogeneity was presented in this meta-analysis due to the variety of sample size, intervention items, frequency, duration, and control items. Second, the study population varied from each other, especially age and gender. Third, there were only data on short-term outcomes (3 to 6 months after interventions), and no available data on the mid- or long-term (more than 6 months) effects of virtual reality–based training for participants with chronic low back pain. These findings indicated that more studies are required to strengthen the evidence.

Implications for Clinical Practice and Future Research

Despite the low level of certainty, these findings may provide important implications for health care professionals. In clinical practice, the virtual reality–based training may be recommended for patients with chronic low back pain in order to distract and reduce the focus on pain. However, the persistence of efficacy needs to be considered when applying virtual reality–based training. Based on the present evidence in this study, it may be even better for immediate effects. Furthermore, the virtual reality–based training should be tailored to the needs and characteristics of patients in order to optimize the performance and maintain the efficacy. Future research should focus on different types of virtual reality, intervention parameters (eg, types, frequency, intensity, and time), and different population. These issues require further refinement through larger sample sizes, longer intervention duration, and longer follow-ups. In addition, it is urgent to explore the feasibility of virtual reality–based training in different socioeconomic contexts to ensure broader and cost-effective access to this type of intervention.

Conclusions

In general, these findings support that virtual reality–based training is a promising treatment strategy for individuals with chronic low back pain immediately after interventions, especially to alleviate pain, pain-related fear, and disability. However, there is still not sufficient evidence to suggest that virtual reality–based training is effective in chronic low back pain in the short term. More high-quality RCTs are required to find short- and long-term benefits and to obtain more robust evidence.

Abbreviations

GRADE

Grading of Recommendations, Assessment, Development and Evaluation

MCID

minimal clinically important difference

MD

mean difference

ODI

Oswestry Disability Index

PRISMA

Preferred Reporting Items for Systematic Reviews and Meta-Analyses

RCT

randomized controlled trial

Data Availability

The data sets generated and analyzed during this study are available from the corresponding author on reasonable request.