후관절, 천장관절 연관통 감별을 위한 디테일 ...2023 Lancet !!

[문형철]

https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00137-2/fulltext

일차 진료에서 요통의 원인을

추간판, SIJ, 또는 후관절로 식별하는 진단 검사의 정확도가 불확실하다.

이 체계적 문헌고찰은

62개 연구(추간판 35개, 후관절 14개, SIJ 11개, 세 가지 모두 2개)를 포함하며,

대부분 지속성 요통 환자를 대상으로 했다.

편향 위험은 참조 표준 영역에서 가장 높았다.

추간판의 경우,

MRI에서 추간판 퇴행(grade ≥3)과 환상 균열(annular fissure)은

유의미한 양성 우도비(+LR) 2.53(95% CI: 1.57–4.07)과 2.88(95% CI: 2.02–4.10),

음성 우도비(−LR) 0.15(95% CI: 0.09–0.24)와 0.24(95% CI: 0.10–0.55)를 보였다.

Modic type 1/2 변화와 고강도 영역(HIZ)은

+LR이 높았으나 −LR은 유의미하지 않았다.

후관절의 경우,

SPECT 흡수는 +LR 2.80(95% CI: 1.82–4.31), −LR 0.44(95% CI: 0.25–0.77)로 유의미했다.

SIJ의 경우,

통증 유발 검사 조합과 정중선 요통 부재는 +LR 2.41–2.44, −LR 0.31–0.35로 유의미했으며,

방사성 핵종 영상은 +LR 7.33이지만 −LR은 유의미하지 않았다.

일부 요통 환자에서 진단이 가능하며,

표적 치료를 안내할 수 있다.

배경

요통은 흔하며,

첫 발병 1년 발생률 6.3%–15.4%,

1개월 유병률 23.2%로 나이 들수록 증가한다.

대부분 비특이적 요통(NSLBP)으로 분류되지만,

운동, 약물, 수기 요법 등의 광범위 치료 효과는 작다.

특정 원인(추간판, 후관절, SIJ)을 식별하면

맞춤 치료가 가능하다.

2007년 문헌고찰을 업데이트하여 2006년 3월부터 2023년 1월까지의 연구를 포함했다.

방법

PROSPERO 등록(CRD42020169828), PRISMA 지침 준수. MEDLINE, CINAHL, EMBASE 검색, 인용 추적. 심각 병리 없는 요통 환자 대상, 참조 표준(추간판 조영술, 국소 마취 블록) 사용 연구 포함. QUADAS-2로 편향 위험 평가. 동질 연구 풀링(random-effects 모델), +LR ≥2 또는 −LR ≤0.5를 유의미 기준으로 함. 민감도 분석 실시.

주요 결과

62개 연구 포함(중앙 표본 크기 55명, 대부분 3차 진료, 지속성 요통). 편향 위험: 참조 표준에서 낮은 비율(27%).

• 추간판: MRI 추간판 퇴행 +LR 2.53, −LR 0.15; 환상 균열 +LR 2.88, −LR 0.24; HIZ +LR 3.10, −LR 0.61; Modic type 1 +LR 10.00, −LR 0.84; Modic type 2 +LR 8.03, −LR 0.88; 중심화(centralisation) +LR 3.06, −LR 0.66.
• 후관절: SPECT 흡수 +LR 2.80, −LR 0.44.
• SIJ: 방사성 핵종 영상 +LR 7.33, −LR 0.74; 정중선 요통 부재 +LR 2.41, −LR 0.35; 3개 이상 양성 유발 검사 +LR 2.44, −LR 0.31.

엄격 참조 표준에서 일부 LR 개선. 중간 유병률: 추간판 46%, SIJ 53%, 후관절 42%.

논의

2007년 고찰 업데이트로 더 많은 연구 풀링, 일부 검사 유의미 확인. 비특이적 요통 개념에 도전하며 하위 그룹 진단 가능성 제안. 강점: 포괄 검색, 풀링. 한계: 3차 진료 편향, 이질성, 1차 진료 연구 부족. 함의: 표적 치료 가능하나 결과 연구 필요. 미래: 예후/치료 반응, 다른 원인(근육, 인대), 비용 효과 연구.

결론

추간판(MRI 퇴행, HIZ, 환상 균열, Modic 변화, 중심화), SIJ(유발 검사, 정중선 통증 부재, 핵종 영상), 후관절(SPECT 흡수)에 유의미 진단 검사 존재. 지속성 요통 하위 그룹 진단 가능, 특정 치료 전환 촉진. 임상 유용성, 결과, 임계값 연구 필요.

https://pmc.ncbi.nlm.nih.gov/articles/PMC6206372/

Facet joint syndrome: from diagnosis to interventional management - PMC

요통(LBP)은

가장 흔한 통증 증후군으로 사회적 부담이 크다.

요추 후관절(FJs)은

LBP의 15–45%에서 원인이 되며,

퇴행성 골관절염이 가장 빈번하다.

병력과 신체 검사로

FJ 증후군을 의심할 수 있지만

확진은 불가능하다.

영상(방사선, MRI, CT, SPECT)은 흔히 사용되지만

증상과 퇴행성 변화 간 상관관계가 신뢰할 수 없다.

진단적 FJ 블록으로 FJ를 통증 원인으로 확인할 수 있으며,

신경절제(라디오주파수 또는 냉동절제) 같은 중재적 치료를 가능하게 한다.

이 리뷰는

FJ 해부학, 역학, 임상 양상, 방사선 소견, 중재적 관리에 대해 다룬다

.

주요 교육 포인트:

• 요추 FJ는 LBP의 15–45%를 차지한다.
• 후관절 관절증이 가장 흔한 병리.
• 증상, 검사, 퇴행성 변화 간 상관관계 없음.
• 양성 FJ 블록으로 FJ 통증 원인 확인.
• 선택된 환자에서 FJ 신경절제(라디오주파수 또는 냉동절제) 혜택 가능.

키워드: 요통, 후관절, 블록, 신경절제, 라디오주파수, 냉동절제

서론/배경

만성 요통은 유병률이 높아 사회적 비용이 막대하다. 요추 FJ는 흔한 통증 원인이지만 오진과 오치료가 빈번하다. FJ 골관절염이 주요 병리다. 영상은 자주 사용되지만 증상과 상관이 부족하다. FJ 증후군은 일측 또는 양측 등 통증으로 엉덩이, 사타구니, 허벅지(무릎 위)로 방사되며, 때로 디스크나 신경근 문제를 흉내낸다. 병력과 검사로 의심되지만 확진되지 않음. 양성 FJ 블록으로 통증 원인을 확인해 스테로이드 주사나 신경절제를 가능하게 함. 보존적 치료 실패 후 중재. 방사선과 의사가 영상과 중재에서 핵심 역할. 이 리뷰는 FJ 역학, 해부학, 병태생리, 영상, 중재를 다룸.

방법

이 논문은 FJ 증후군에 대한 서술적 리뷰로, 문헌을 종합. 해부학, 역학, 임상 특징, 영상, 중재적 관리에 대한 연구를 바탕으로 함. 유병률, 진단 정확도, 치료 효과에 대한 연구를 인용. 진단을 위한 제어된 블록과 치료를 위한 안내 중재(CT-형광투시)를 강조. 구체적 실험 방법 없음; 시체, 임상, 영상 연구 증거 수집.

주요 결과 (주요 발견, 데이터, 그림/표)

• 역학: LBP 유병률 15–45% (단면 연구). 젊은 성인 만성 LBP에서 FJ 기여 10–15%, 통제 연구에서 27–40%, 노인에서 더 높음 (부상 노동자 15%, 이질 그룹 40–45%). 비용 높음 (독일 연간 489억 유로).
• 해부학: FJ는 활액 관절로, 디스크와 인대와 함께 3관절 복합체. 등쪽 가지의 내측 가지로 신경지배 (이중 공급: 동일 레벨과 위). 변이: 요천추 이행 척추 (4–30%). 신경 분포 상세 (Fig. 1): 내측, 중간, 측면 가지; L5 독특.
• 원인: 퇴행성 골관절염 (가장 흔함; Fig. 2: 관절 협착, 비대, 진공 현상); 척추전방전위증 (L4–5; Fig. 3: 용해, 변위); 패혈성 관절염 (희귀; Fig. 4: 삼출, 부종); 염증성 (류마티스 관절염 등).
• 임상 양상: 통증 엉덩이, 사타구니, 허벅지(무릎 위)로 방사 (Fig. 5: 방사 패턴). 신전, 회전, 비활동으로 악화. 시아티카 흉내지만 결손 없음. 검사만으로 진단 타당성 낮음.
• 영상 소견 (Table 1: X-ray, MRI, CT, SPECT 특징: 관절 협착, 경화, 비대, 낭종 등):
  • X-ray/CT: 협착, 경화, 비대, 낭종.
  • MRI: 삼출, 부종 (STIR/T2), 조영증강 (가돌리늄), CT 대비 심각도 과소평가 (Fig. 6).
  • SPECT: 과고정 (Fig. 7: 염증 표시).
  • 분류: Pathria (1–3등급), Weishaupt, Fujiwara (MRI 기반); 영상 역할 합의 없음 (증상 상관 부족).
• 중재적 관리:
  • 블록: 내측 가지 선호 (관절내 대비 특이도 높음); 80%+ 통증 완화 기준; 이중 공급으로 이중 레벨 (Fig. 8).
  • 스테로이드 주사: 단기 완화; 가이드라인에서 관절내 권장 안 함.
  • 신경절제 (Table 2: RF vs. CN vs. 화학):
    • RF: 60–80% 환자 60–90% 완화 (12개월; Fig. 9); 합병증 희귀 (1%).
    • CN: 50% 통증 감소 (6주–6개월; Fig. 10); 조직 손상 적음.
    • 화학: 일시적 (3–6개월); 괴사, 신경염 위험.
  • 선택: 블록, 통증 지도, 영상 (SPECT 흡수) 기반.
  • 기술: CT 안내; 안전 위해 자극 (Fig. 11: 바늘).
  • 기타: PRP 주사 연구에서 우수 효과; 레이저 방사, MRI 안내 초음파 실험적.

주요 데이터: 단일 블록 위양성 30–45%; 이중 블록으로 성공 64% 상승. 신경절제 반복 가능 (연 2회 max).

논의

FJ 증후군은 비특이적 증상과 영상-무의미 소견으로 과소진단됨. 블록 필수로 진단, 내측 가지 블록 우수. 중재는 보존 실패 후 완화 제공하나 재생 제한으로 지속성 한계. RF와 CN 주류; CN 더 안전할 수 있음. 방사선과 의사 역할 핵심 (안내 시술). 수술 (관절고정술) FJ 통증 증거 부족; 비수술 선호. 신흥 치료 (PRP, 레이저) 추가 연구 필요.

결론

FJ 증후군은 LBP 부담 크지만 임상-영상 상관 부족으로 오진됨.

진단 블록으로 원인 확인,

선택 환자에서 신경절제 (RF/냉동절제)로 장기 완화.

방사선과 의사 진단 (영상)과 치료 (중재)에서 핵심.

다모달 보존 관리 우선; 실패 시 중재.

SummaryBackground

The accuracy of diagnostic tests available in primary care to identify the disc, sacroiliac joint, and facet joint as the source of low back pain is uncertain.

Methods

Systematic review of diagnostic tests available in primary care. MEDLINE, CINAHL, and EMBASE were searched between March 2006 and 25th January 2023. Pairs of reviewers independently screened all studies, extracted data, and assessed risk of bias using QUADAS-2. Pooling was performed for homogenous studies. Positive likelihood ratios (+LR) ≥2 and negative likelihood ratios (−LR) ≤0.5 were considered informative. This review is registered with PROSPERO (CRD42020169828).

Findings

We included 62 studies: 35 investigated the disc, 14 the facet joint, 11 the sacroiliac joint, and 2 investigated all three structures in patients with persistent low back pain. For risk of bias, the domain ‘reference standard’ scored worst, however approximately half the studies were of low risk of bias for every other domain. For the disc, pooling demonstrated MRI findings of disc degeneration and annular fissure resulted in informative +LRs: 2.53 (95% CI: 1.57–4.07) and 2.88 (95% CI: 2.02–4.10) and −LRs: 0.15 (95% CI: 0.09–0.24) and 0.24 (95% CI: 0.10–0.55) respectively. Pooled results for Modic type 1, Modic type 2, and HIZ on MRI, and centralisation phenomenon yielded informative +LRs: 10.00 (95% CI: 4.20–23.82), 8.03 (95% CI: 3.23–19.97), 3.10 (95% CI: 2.27–4.25), and 3.06 (95% CI: 1.44–6.50) respectively, but uninformative −LRs: 0.84 (95% CI: 0.74–0.96), 0.88 (95% CI: 0.80–0.96), 0.61 (95% CI: 0.48–0.77), and 0.66 (95% CI: 0.52–0.84) respectively. For the facet joint, pooling demonstrated facet joint uptake on SPECT resulted in informative +LRs: 2.80 (95% CI: 1.82–4.31) and −LRs: 0.44 (95% CI: 0.25–0.77). For the sacroiliac joint, a combination of pain provocation tests and absence of midline low back pain resulted in informative +LRs of 2.41 (95% CI: 1.89–3.07) and 2.44 (95% CI: 1.50–3.98) and −LRs of 0.35 (95% CI: 0.12–1.01) and 0.31 (95% CI: 0.21–0.47) respectively. Radionuclide imaging yielded an informative +LR 7.33 (95% CI: 1.42–37.80) but an uninformative −LR 0.74 (95% CI: 0.41–1.34).

Interpretation

There are informative diagnostic tests for the disc, sacroiliac joint, and facet joint (only one test). The evidence suggests a diagnosis may be possible for some patients with low back pain, potentially guiding targeted and specific treatment approaches.

일차 진료에서 이용 가능한 진단 검사의 정확성은

허리 통증의 원인으로서

추간판(disc),

천장관절(sacroiliac joint), 그리고

후관절(facet joint)을 식별하는 데 불확실하다.

방법

일차 진료에서 이용 가능한 진단 검사의 체계적 검토. MEDLINE, CINAHL, 및 EMBASE를 2006년 3월부터 2023년 1월 25일까지 검색하였다. 검토자 쌍이 모든 연구를 독립적으로 선별하고, 데이터를 추출하며, QUADAS-2를 사용하여 편향 위험을 평가하였다. 동질적인 연구에 대해 풀링(pooling)을 수행하였다.

양성 우도비(+LR) ≥2와 음성 우도비(−LR) ≤0.5를 유익한 것으로 간주하였다.

이 검토는 PROSPERO(CRD42020169828)에 등록되었다.

결과

우리는 62개의 연구를 포함하였다:

35개는 추간판을,

14개는 후관절을,

11개는 천장관절을, 그리고

2개는 지속적인 허리 통증 환자에서 세 구조 모두를 조사하였다.

편향 위험에 대해, ‘참조 표준(reference standard)’ 영역이 가장 나빴으나, 다른 모든 영역에 대해 연구의 약 절반이 낮은 편향 위험을 보였다.

추간판에 대해, 풀링 결과 MRI 소견 중

추간판 퇴행(disc degeneration)과 환상 균열(annular fissure)은

유익한 +LR: 2.53(95% CI: 1.57–4.07) 및 2.88(95% CI: 2.02–4.10)과

−LR: 0.15(95% CI: 0.09–0.24) 및 0.24(95% CI: 0.10–0.55)를 각각 나타냈다.

MRI 상 Modic type 1, Modic type 2, HIZ,

그리고 중심화 현상(centralisation phenomenon)에 대한 풀링 결과는

유익한 +LR: 10.00(95% CI: 4.20–23.82), 8.03(95% CI: 3.23–19.97), 3.10(95% CI: 2.27–4.25), 및 3.06(95% CI: 1.44–6.50)을 각각 나타냈으나,

비유익한 −LR: 0.84(95% CI: 0.74–0.96), 0.88(95% CI: 0.80–0.96), 0.61(95% CI: 0.48–0.77), 및 0.66(95% CI: 0.52–0.84)을 나타냈다.

후관절에 대해, 풀링 결과 SPECT 상 후관절 흡수(facet joint uptake)는

유익한 +LR: 2.80(95% CI: 1.82–4.31)과 −LR: 0.44(95% CI: 0.25–0.77)를 나타냈다.

천장관절에 대해, 통증 유발 검사(pain provocation tests)의 조합과 정중선 허리 통증의 부재(midline low back pain absence)는 유익한 +LR 2.41(95% CI: 1.89–3.07) 및 2.44(95% CI: 1.50–3.98)과 −LR 0.35(95% CI: 0.12–1.01) 및 0.31(95% CI: 0.21–0.47)을 각각 나타냈다. 방사성 핵종 영상(radionuclide imaging)은 유익한 +LR 7.33(95% CI: 1.42–37.80)을 나타냈으나, 비유익한 −LR 0.74(95% CI: 0.41–1.34)를 나타냈다.

해석

추간판, 천장관절, 그리고 후관절(단 하나의 검사만)에 대한 유익한 진단 검사가 있다. 증거는 허리 통증 환자 중 일부에서 진단이 가능할 수 있음을 시사하며, 이는 잠재적으로 표적화되고 구체적인 치료 접근을 안내할 수 있다

Funding

There was no funding for this study.

Keywords

1. Diagnosis
2. Pathoanatomical
3. Low back pain
4. Reference standard
5. Index test

Research in context

Evidence before this study

Our previous review conducted in 2007 found relatively few studies had investigated the diagnostic accuracy of tests to identify the disc, facet joint or sacroiliac joint as the source of low back pain. Pooling was limited due to heterogeneity between studies and poor study quality. The diagnostic accuracy of index tests was unclear.

Added value of this study

In this new study a greater number of studies were able to be pooled, resolving some uncertainty about diagnostic accuracy. Considering an informative diagnostic test as one with a likelihood ratio ≥2.0 or ≤0.5; there were informative tests for the disc, sacroiliac joint, and the facet joint. The review provides evidence that a diagnosis may be possible for some patients with low back pain, potentially guiding clinical management.

Implications of all the available evidence

Our study identifies tests available to primary care clinicians to identify the disc and sacroiliac joint as the source of low back pain and creates opportunities for more targeted and specific treatment approaches. Future research should investigate if this targeted approach provides better outcomes than generic, symptomatic treatment of low back pain.

Introduction

Low back pain is a very common condition, and most people will experience low back pain in their life. For example, the one year incidence of experiencing a first ever episode of low back pain is approximately 6.3%–15.4%, with estimates for the one year incidence of any episode of low back pain being as high as 36%.1 The one month preval‎ence of low back pain is estimated to be 23.2% in the general population.1 The preval‎ence of low back pain also increases with age,2 by 80 years old, the preval‎ence estimates are as high as 40% in males and 35% in females.2 Low back pain is a symptom and is typically defined as pain between the bottom ribs and the buttock creases.3

Currently, most clinical practice guidelines recommend broad treatment approaches such as exercise, medication, or manual therapy for patients with NSLBP4; however these interventions typically have small average effects5 and there is little to no information and guidance provided on how to individualise these treatments for patients with low back pain. Despite the enormous burden of low back pain, the approach to move the field forward remains unclear. One view is that a diagnosis may lead to the development of more specific and targeted treatments.

A diagnosis, however, is controversial in the low back pain field. The dominant view4 is that for 90% of patients with low back pain (LBP) the pain cannot be attributed to a specific pathology or structure; and these patients should be classified as having non-specific low back pain. An alternate position is that subclassification of non-specific low back pain is possible, by using features from the clinical presentation, clinical assessment, and diagnostic imaging to identify a nociceptive source.6 The latter approach would allow more precise approaches to the management of low back pain that target an underlying pathology.

The disc, facet joint, and sacroiliac joint (SIJ) are potential sources of low back pain.7 Most reference standards used to identify the source of low back pain, such as invasive disc provocation procedures or diagnostic blocks, are neither suitable nor available for routine use in primary care. Therefore, there is interest in identifying simpler diagnostic tests to help identify the nociceptive source of low back pain. Our previous 2007 systematic review7 identified relatively few studies that had investigated the diagnostic accuracy of tests to identify the source of low back pain, limiting the ability to pool results. The systematic review did find that some tests such as MRI evidence of a high intensity zone and disc degeneration, and centralisation phenomenon (i.e., repeated end-range movements that result in distal pain originating from the spine progressively moving towards a central location)8 increased (when present) or decreased (when absent) the likelihood of the disc being the source of low back pain.7 A combination of sacroiliac joint provocation tests also modestly increased (when positive) or decreased (when negative) the likelihood of the sacroiliac joint being the source of LBP.7 No index tests for the facet joint were found to be informative.7

The previous review has been highly cited, however it is now over 15 years old.7 Additional primary studies investigating the diagnostic tests for the disc, facet joint, and sacroiliac joint have since been published and are likely to enable more pooling of results and greater confidence in the findings. Therefore, an update of this review was performed to determine the accuracy of diagnostic tests for the disc, sacroiliac joint, or facet joint as the source of low back pain.

Methods

The systematic review protocol was pre-specified and registered on PROSPERO (CRD42020169828): https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020169828. The current review protocol was registered with PROSPERO (CRD42015029729). Its reporting followed the guidelines of the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA).9

Search strategy

MEDLINE, CINAHL, and EMBASE were searched for the period between March 2006 and 25th January 2023 with the search strategy used in the Hancock et al., 2007 review.7 The complete search strategies from all databases are presented in Supplementary Appendix S1. We also screened reference lists of included studies. Forward citation searching was also performed. We included studies in all languages.

Eligibility criteria

Studies were required to meet the following criteria (also used in the previous review7) to be eligible.

i)

Included participants with low back pain without serious pathology such as cancer, infection, or fracture

ii)

used a reference standard test advocated by the International Association for the Study of Pain.10 These were: discography for discogenic pain (with a minimum of two levels tested per patient), intra-articular local anaesthetic blocks for SIJ pain, and either intra-articular blocks or medial branch blocks for facet joint pain

iii)

Assessed at least one index test available to primary care clinicians

iv)

Presented a 2 × 2 contingency table, or data allowing development of contingency table(s).

One review author (SwS) excluded clearly irrelevant titles. Two review authors (SwS, AT, or SaS) independently screened abstracts to exclude irrelevant studies. Two reviewers (SwS, AT, SaS, or CSH) then independently reviewed full texts for eligibility based on the inclusion criteria. Studies in languages other than English were screened by a researcher fluent in the appropriate language. Disagreements were resolved through discussion and a third reviewer (CGM or MJH).

Data and statistical analysis

Two review authors independently extracted data into the data extraction form. Any disagreements or discrepancies in the data extraction were resolved through discussion and a third reviewer (CGM or MJH) if necessary. This form was used to record study population, hypothesised nociceptive/tissue source of low back pain, index tests, sensitivity, specificity, the positive (+LR) and negative (−LR) likelihood ratios and 95% confidence intervals (95% CI). We prioritised using raw data when available to calculate the sensitivity, specificity, +LR, −LR, and 95% CIs.

Two review authors (SwS, AT, SaS, or CH) used the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) scale11 independently to rate risk of bias. This tool eval‎uates four domains such as patient selection; index test; reference standard; and flow and timing.11 Each author independently rated the risk of bias in each of the four domains (guided by signalling questions). Further details on the decision-making process of study quality are presented in Supplementary Appendix S5. Any disagreements were resolved through discussion and a third reviewer (CGM or MJH).

Following data extraction, data were pooled whenever possible using random effects models. The software used for meta-analysis and to calculate sensitivities, specificities, and likelihood ratios from raw data (2 × 2 tables) was Meta-DiSc v1.4. Due to limited data for most index tests, pooling was not always possible, and results of individual tests were also presented descriptively.

Potential publication bias was assessed post-hoc using the midas command12 in Stata version 17/BE. To eval‎uate potential publication bias, funnel plots were explored, and Deeks Funnel Plot Asymmetry Test was used to explore funnel plot asymmetry. Publication bias was deemed statistically significant if the p value was <0.05. As per the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy Version 2.0, 2022 (Chapter 11.5.5) we only assessed for publication bias if ten or more studies were included in the analysis for a single test.13

For index tests scored as either positive or negative we calculated the sensitivity, specificity, and likelihood ratios. We also presented post-test probabilities using standard methods with the “95% confidence interval for post-test probability determined with point estimate of pre-test probability and the 95% confidence interval of the likelihood ratio.”14 For index tests with different thresholds to score as positive or negative, these results are presented descriptively to show the estimates of sensitivities and specificities for each test cut-off.

We focused on likelihood ratios in our results; however, sensitivity and specificity are presented in Table 1 and Supplementary Appendix S6. We considered the index test to be informative if the positive likelihood ratios (+LR) were ≥2 and negative likelihood ratios (−LR) were ≤0.5.49,50

Index testStudies/total sampleSensitivity (95% CI)Specificity (95% CI)+LR (95% CI)−LR (95% CI)

Disc
Disc degeneration (Grade ≥3)15–18	4/381	91.0 (85.7–94.7)	61.3 (54.2–68.0)	2.53 (1.57–4.07)	0.15 (0.09–0.24)
Heterogeneity (I2)		50.1%	82.7%	83.4%	0.0%
bDisc degeneration (Grade ≥4)16,18,19	3/288	70.7 (60.7–79.4)	66.7 (59.5–73.3)	2.20 (1.61–3.01)	0.37 (0.19–0.73)
Heterogeneity (I2)		84.7%	87.7%	44.4%	59.9%
HIZ18–29	12/1817	50.1 (46.7–53.4)	86.2 (83.9–88.4)	3.10 (2.27–4.25)	0.61 (0.48–0.77)
Heterogeneity (I2)		95.4%	65.6%	63.6%	92.2%
Annular fissure22,25,30–32	5/920	61.2 (56.3–66.0)	73.8 (69.8–77.5)	2.88 (2.02–4.10)	0.24 (0.10–0.55)
Heterogeneity (I2)		96.0%	94.3%	79.5%	90.3%
Modic type18,24,25,33	4/803	12.9 (9.7–16.6)	98.7 (97.0–99.5)	10.00 (4.20–23.82)	0.84 (0.74–0.96)
Heterogeneity (I2)		91.0%	0.0%	0.0%	89.2%
Modic type18,25,34	3/706	12.0 (8.9–15.9)	98.6 (96.7–99.5)	8.03 (3.23–19.97)	0.88 (0.80–0.96)
Heterogeneity (I2)		77.3%	0.0%	0.0%	65.8%
aCentralisation phenomenon33,35–37	4/218	41.2 (33.2–49.6)	85.9 (75.6–93.0)	3.06 (1.44–6.50)	0.66 (0.52–0.84)
Heterogeneity (I2)		79.9%	66.1%	10.8%	57.9%
SIJ
Radionuclide imaging (bone scan)38,39	2/82	22.7 (11.5–37.8)	96.1 (84.4–99.7)	7.33 (1.42–37.8)	0.74 (0.41–1.34)
Heterogeneity (I2)		81.4%	0.0%	0.0%	80.2%
aGaenslen's test40–43	4/213	47.9 (38.7–57.2)	47.9 (37.5–58.4)	0.85 (0.56–1.28)	1.12 (0.77–1.62)
Heterogeneity (I2)		72.3%	73.3%	46.5%	34.3%
aSacral thrust test40,41,43	3/168	57.3 (45.9–68.2)	48.8 (37.9–59.9)	1.13 (0.73–1.75)	0.87 (0.52–1.44)
Heterogeneity (I2)		42.5%	84.1%	59.7%	47.7%
aThigh thrust test40–44	5/415	54.1 (48.1–60.1)	53.7 (44.9–62.3)	1.13 (0.83–1.55)	0.91 (0.67–1.22)
Heterogeneity (I2)		74.6%	31.0%	42.5%	42.1%
aCompression test41,43	2/83	48.6 (31.9–65.6)	71.7 (56.5–84.0)	1.79 (1.03–3.11)	0.74 (0.52–1.05)
Heterogeneity (I2)		56.0%	0.0%	0.0%	0.0%
aPatrick's test (FABER test)40,43,44	3/319	76.4 (70.2–81.8)	32.3 (23.3–42.5)	1.05 (0.69–1.60)	0.86 (0.30–2.48)
Heterogeneity (I2)		80.3%	55.0%	80.7%	84.9%
aDistraction test41,43	2/82	41.7 (25.5–59.2)	80.4 (66.1–90.6)	2.18 (1.08–4.38)	0.73 (0.54–0.99)
Heterogeneity (I2)		0.0%	0.0%	0.0%	0.0%
aGillet's test40,42	2/134	67.5 (56.4–77.3)	45.5 (31.2–60.2)	1.01 (0.80–1.28)	1.08 (0.75–1.55)
Heterogeneity (I2)		97.5%	89.2%	23.8%	0.0%
aAbsence of midline LBP37,45	2/226	24.6 (14.1–37.8)	34.3 (27.2–42.0)	2.41 (1.89–3.07)	0.35 (0.12–1.01)
Heterogeneity (I2)		80.2%	0.0%	0.0%	75.6%
a3 or more positive SIJ pain provocation tests37,41,43,46–48	6/276	80.5 (72.0–87.4)	68.1 (60.4–75.2)	2.44 (1.50–3.98)	0.31 (0.21–0.47)
Heterogeneity (I2)		0.0%	69.1%	76.6%	0.0%
Facet joint
Uptake on SPECT	3/121	72.6 (59.1–83.6)	72.3 (59.8–82.7)	2.80 (1.82–4.31)	0.44 (0.25–0.77)
Heterogeneity (I2)		31.1%	0.0%	0.0%	7.0%

Table 1

Pooled diagnostic values of index tests.

All magnetic resonance imaging (MRI) findings (index tests) are compared to the absence of the respected MRI finding unless indicated.

No index tests based on imaging were able to be pooled for Facet joint.

a

All index tests are based on MRI unless indicated.

b

MRI finding index compared to disc degeneration (Grade ≤3), SIJ = Sacroiliac joint, LR = likelihood ratio, HIZ = high intensity zone, FABER = Flexion abduction external rotation, SPECT = single photon emission computed tomography.

• Open table in a new tab

We pre-specified that we would examine the effect of employing stricter reference standards.51 The stricter reference standards were:51

i)

Discogenic pain studies: discography with a concordant pain provocation score of 6 out of 10 or greater and an adjacent pain-free control disc;

ii)

Facet joint pain studies: greater than or equal to 80% pain relief with double blocks (using a placebo control or comparator local anaesthetic) to account for concurrent pain generators;

iii)

Sacroiliac joint pain studies: greater than or equal to 50% pain relief with double blocks (using a placebo control or comparator local anaesthetic) to account for concurrent pain generators.

We also performed sensitivity analyses post-hoc to examine the effect of study quality (risk of bias) on our findings. We conducted separate sensitivity analyses for each of the four risk of bias domains of the QUADAS-2 scale, each time removing studies at high risk of bias for that domain.

Role of the funding source

There was no funding for this study. The corresponding authors had full access to all the data in the study and had final responsibility for the decision to submit for publication.

Results

After removing duplicates (n = 1093) our search identified 3562 citations. Of these, 2964 were deemed clearly irrelevant based on screening by title and a further 496 studies were excluded based on title and abstract. An additional 23 potentially relevant studies were found by contacting experts in the field and relevant citations were provided to search for the additional studies. Following full-text review by two independent authors, 21 new studies and the 41 studies from the previous review were included for analysis (total 62 studies) (Fig. 1). Excluded studies and primary reasons for exclusion are presented in Supplementary Appendix S2.

Figure viewer

Fig. 1 Study selection.

Six authors16,47,52–55 were contacted for additional data and/or discrepancies, with one author16 able to provide additional data.

The results of the quality assessment using the QUADAS-211 scale are presented in Supplementary Appendix S3 Fig. 2 (studies reporting on the disc) and Fig. 3(studies reporting on the SIJ and facet). The domain which scored worst was ‘reference standard’ where only 17 studies (27%) demonstrated low risk of bias. Low risk of bias scores in the remaining domains were as follows: patient selection (26/62 studies; 42%), index test (34/62 studies; 55%), and flow and timing (30/62 studies; 48%). Seventeen of the 62 (27%) studies demonstrated low concerns for applicability across all domains. Low concerns of applicability scores in the remaining domains were as follows: patient selection (33/62 studies; 53%), index test (54/62 studies; 87%), and reference standard (31/62 studies; 50%). Further details regarding scoring of the domains are presented in Supplementary Appendix S4 and S5.

Of the 62 included studies,15–42,44–48,52–76 35 studies15–36,52,54,55,59,61,66–68,72–76 investigated the disc, 14 studies56–58,60,62–65,70,71 investigated the facet joint and 11 studies38–42,44,46–48,53 the sacroiliac joint. Two studies37,45 investigated all three sources. Studies investigated from 1 to 40 index tests. Sample sizes of the 62 included studies ranged from 15 to 736 (median: 55) and they were conducted in 13 countries. Forty-five studies were conducted in tertiary care, 3 studies in secondary care, and 14 studies were not clear on the healthcare setting. No studies were conducted in primary care. All studies included patients with persistent LBP. The estimated preval‎ence of pain originating from discs, facet joints, and the sacroiliac joint (according to a positive reference test) across all studies demonstrated a median of 46% (IQR: 26%) for discogenic pain, 53% (IQR: 7%) for sacroiliac joint pain, and 42% (IQR: 20%) for facet joint pain. The characteristics of the 60 studies are provided in Table 2.

StudyCountry conductedTissue sourceSample sizeHealthcare setting/Study populationIndex tests

April et al., 1992	Australia	Disc	41	Tertiary care: patients with LBP ± leg pain for >3/12 referred for both MRI and discography.	MRI
Akgun et al., 2022	Turkey	Facet joint	51	Tertiary care: patients with LBP, who underwent single-level facet injection	SPECT
Bartynski et al., 2023	USA	Disc	44	Tertiary care: patients with chronic LBP and referred for discography	MRI
Braithwaite et al., 1998	UK	Disc	58	Tertiary care: patients with chronic LBP ± leg pain who underwent MRI and discography prior to spinal fusion	MRI
Carragee et al., 2002	USA	Disc	25	Tertiary care: patients with mild persistent LBP NOT seeking treatment	MRI
Carrera et al., 1980	USA	Facet joint	48	Not clear: patients with buttock pain ± lumbar or lower extremity symptoms referred for diagnostic injections	CT
Chelala et al., 2019∗	USA	Disc	736	Tertiary care: patients referred for a discogram were potential surgical candidates or candidates for minimally invasive procedures.	MRI
DePalma et al., 2011	USA	Disc, facet joint, SIJ	160	Tertiary care: patients with LBP that was either recalcitrant to spine-focused physical therapy, oral analgesics, or oral anti-inflammatory medications.	Clinical examination
Donelson et al., 1997	USA	Disc	63	Tertiary care: patients with chronic LBP ± lower extremity pain referred for discography. All patients had one or more positive MRI levels.	Clinical examination
Dreyfuss et al., 1996	USA	SIJ	120	Tertiary care: patients presenting to private pain management centre, with chronic LBP ± lower extremity pain.	Clinical examination
Eskander et al., 2015	USA	SIJ	22	Tertiary care: patients with unilateral LBP ± radiation to lower extremity for >2/12.	Clinical examination, Fluoroscopic exam
Freiermuth et al., 2015	Switzerland	Facet joint	29	Tertiary care: patients with LBP >3/12 referred to pain relief unit.	SPECT/CT
Gornet et al., 2019	USA	Disc	139	Tertiary care: patients with LBP who underwent both MRS and discography.	MRS
Hanna et al., 2013	Sweden	Disc	35	Tertiary care: patients with LBP >6/12 that failed conservative therapy and referred for preoperative lumbar discography	MRI
Helbig et al., 1988	USA	Facet joint	22	Tertiary care: patients who underwent lumbar facet joint injection for LBP and leg pain	Clinical examination, radiograph
Holder et al., 1995	USA	Facet joint	19	Tertiary care: patients referred with a diagnosis of possible facet syndrome	SPECT
Horton et al., 1992	USA	Disc	25	Tertiary care: patients being considered for operative intervention who underwent MRI and discography.	MRI
Ito et al., 1998	USA	Disc	39	Not clear: patients with chronic LBP studied with MRI and discography	MRI
Kang et al., 2009	South Korea/USA	Disc	62	Tertiary care: patients with severe LBP that was likely to be disc related ± radiation to lower limb extremity.	MRI
Koh et al., 2011	South Korea	Facet joint	33	Not clear: patients with chronic LBP >6/12.	SPECT
Kokkonen et al., 2002	Finland	Disc	36	Tertiary care: patients admitted to hospital because of chronic LBP of unclear but suspected discogenic origin.	MRI
Lam et al., 2000	UK	Disc	73	Tertiary care: patients considered for spinal fusion. All patients had at least one positive HIZ	MRI
Laslett et al., 2003	USA	SIJ	200	Tertiary care: patients presenting to private pain management centre, with chronic LBP ± lower extremity pain.	Clinical examination
Laslett et al., 2004	USA	Facet joint	116	Tertiary care: patients with chronic LBP ± lower extremity symptoms referred to diagnostic radiology practice.	Clinical examination
Laslett et al., 2005a	USA	Disc	83	Tertiary care: patients with chronic LBP ± leg pain and abnormal MRI referred to diagnostic injections	Clinical examination
Laslett et al., 2005b	USA	SIJ	32	Tertiary care: patients with unilateral LBP ± posterior thigh pain for more than 7 weeks. All patients had tenderness over SIJ joint line.	Clinical examination
Laslett et al., 2006a	USA	Disc	216	Tertiary care: patients with persistent LBP ± radiation to lower limb extremity referred to a private radiology practice specializing in the diagnosis of spinal pain.	Clinical examination
Laslett et al., 2006b	USA	Facet joint	151	Tertiary care: patients with persistent LBP ± radiation to lower limb extremity referred to a private radiology practice specializing in the diagnosis of spinal pain.	Clinical examination
Lei et al., 2008	UK	Disc	55	Tertiary care: patients with disabling LBP that were likely to be disc related. Candidates for spinal surgery also included.	MRI
Lewinnek et al., 1986	USA	Facet joint	21	Not clear: patients with LBP	Clinical examination
Lim et al., 2005	South Korea	Disc	47	Not clear: patients with chronic LBP who underwent both discography and MRI. Disc degeneration but no neural compression on MRI.	MRI
Maigne et al., 1998	France	SIJ	42	Tertiary care: patients with LBP >3/12 referred for facet injection. 40 patients with LBP but not true sciatica 86 chronic LBP patients referred for facet joint blocks 10 patients with LBP ± leg pain	Radionuclide image
Manchikanti et al., 1999	USA	Facet joint	120	Secondary care: patients presenting to private pain management centre, with chronic LBP ± lower extremity pain.	Clinical examination
Manchikanti et al., 2000	USA	Facet joint	200	Secondary care: patients presenting to private pain management centre, with chronic LBP ± lower extremity pain.	Clinical examination
Mekhail 2021	USA	SIJ	199	Tertiary care: patients with LBP eval‎uated by diagnostic SIJ injections	Clinical examination
Milette et al., 1990	Canada	Disc	100	Not clear: patients with subjective complaints suggestive of HNP but no neurological deficits.	CT
Nejati 2020	Iran	SIJ	48	Secondary care: patients with LBP or buttock pain with or without lower extremity pain	Clinical examination
O'Neill et al., 2008	Canada	Disc	143	Tertiary care: patients with LBP >6/12. No neurologic deficits, no previous surgery, and had an MRI.	MRI
Ohnmeiss et al., 1999	USA	Disc	187	Not clear: patients with LBP ± lower extremity pain who underwent discography.	Clinical examination
Osti et al., 1992	Australia	Disc	33	Tertiary care: patients investigated for LBP	MRI
Parker et al., 1996	USA	Disc	15	Tertiary care: patients with chronic LBP ± leg pain referred for MRI and discography prior to surgery.	MRI
Revel et al., 1992	France	Facet joint	60	Not clear: patients with chronic LBP below L5, over one SIJ ± leg pain referred for diagnostic injections.	Clinical examination
Revel et al., 1998	France	Facet joint	42	Tertiary care: patients with LBP >3/12 referred for facet injection. 40 patients with LBP but not true sciatica 86 chronic LBP patients referred for facet joint blocks 10 patients with LBP ± leg pain	Clinical examination
Ricketson et al., 1996	USA	Disc	29	Not clear: patients with LBP ± radicular symptoms who underwent both MRI and discography.	MRI
Saifuddin et al., 1998	UK	Disc	58	Tertiary care: patients with chronic non-radicular LBP who underwent both MRI and discography before possible spinal fusion	MRI
Schellhas et al., 1996	USA	Disc	63	Not clear: patients who underwent MRI and Discography for LBP and had at least one positive HIZ level	MRI
Schneider et al., 2020	USA	SIJ	39	Tertiary care: patients referred for SIJ injection	Clinical examination
Simmons et al., 1991	USA	Disc	164	Not clear: patients with LBP ± radicular symptoms	MRI
Slipman et al., 1996	USA	SIJ	50	Tertiary care: patients referred to spine centre with LBP ± leg pain. Positive physical examination on at least 3 SIJ tests.	Radionuclide image
Smith et al., 1998	USA	Disc	55	Tertiary care: patients who underwent both lumbar discography and MRI.	MRI
Stanford et al., 2010	Canada	SIJ	34	Not clear: patients with LBP that was refractory to non-invasive conservative spine treatment for >6/12	Clinical examination
Stojanovic et al., 2010	USA	Facet joint	119	Not clear: patients with chronic LBP unresponsive to conservative therapy	MRI
van der Wurff et al., 2006	Netherlands	SIJ	85	Tertiary care: patients referred for SIJ blocks, with pain principally below L5	Clinical examination
Vanharanta et al., 1988	USA	Disc	107	Not clear: patients with LBP where ‘‘discography was indicated’’ and plain radiograph had been previously performed.	Plain radiograph
Vanharanta et al., 1998	USA	Disc	78	Tertiary care: patients with chronic LBP ± leg pain, who underwent MRI and discography	MRI, vibration
Waldrop et al., 2021	USA	Disc	736	Tertiary care: patients referred for lumbar spine discography	MRI
Weishaupt et al., 2001	Switzerland	Disc	50	Tertiary care: patients with severe chronic LBP who were candidates for surgery and had abnormal MRI.	MRI
Yoshida et al., 2002	Japan	Disc	23	Tertiary care: patients with chronic LBP and leg pain who underwent both MRI and discography.	MRI
Young et al., 2003	USA	Disc, SIJ, Facet joint	81	Tertiary care: patients with chronic lumbopelvic pain referred for diagnostic injections.	Clinical examination
Yrjama et al., 1994	Finland	Disc	57	Tertiary care: patients with LBP	Vibration
Yrjama et al., 1996	Finland	Disc	38	Tertiary care: patients with LBP mostly for several years	Ultrasound, vibration
Yrjama et al., 1997	Finland	Disc	33	Tertiary care: patients with chronic LBP mostly for many years	MRI, vibration

Table 2

Individual study characteristics.

SIJ = sacroiliac joint; LBP = low back pain; MRI = magnetic resonance imaging; MRS = magnetic resonance spectroscopy; CT = computed tomography; SPECT = single-photon emission computerized tomography; HIZ = high intensity zone; HNP = herniated nucleus pulposus; USA = United Stated of America; UK = United Kingdom.

∗

Most index tests in this study52 were excluded as this study only reported the presence or absence of the “worst” disc feature present. For example, if a disc presented with disc degeneration and disc herniation then that disc was categorised as disc herniation only.

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The pooled results are provided in Table 1 and Supplementary Appendix S7. Table 1 and Supplementary Appendix S7 also includes heterogeneity statistics (I2) for the pooled results. Results for individual studies are provided in Supplementary Appendix S6.

Results for index tests for discogenic pain studies that could be pooled across at least two studies are presented below. All MRI studies investigating discogenic pain calculated diagnostic accuracy at the level of the disc, while studies investigating centralisation always calculated diagnostic accuracy at the level of the patient.

Ten studies15–19,22,25,52,54,55 investigated MRI evidence of disc degeneration. Five studies15–19 used the Pfirrmann scale69 and seven studies measured disc degeneration, four using disc nuclear signal22,25,68,72 and three using disc height.19,22,25 Only studies investigating disc degeneration using the Pfirrmann scale (i.e., ≥ grade 3 or ≥ grade 4) were pooled for the main analysis.

For studies measuring disc degeneration using the Pfirrmann scale, we were able to pool four studies investigating disc degeneration with a threshold of ≥ grade 315–18 and three studies investigating disc degeneration with a threshold of ≥ grade 416,18,19 (Table 1). Pooling demonstrated informative +LRs (2.53; 95% CI: 1.57–4.07, I2 = 83.4% and 2.20; 95% CI: 1.61–3.01, I2 = 44.4% for > grade 3 and > grade 4 respectively) and −LRs (0.15; 95% CI: 0.09–0.24, I2 = 0.0%) and 0.37; 95% CI: 0.19–0.73, I2 = 59.9% respectively) (Table 1).

Fourteen studies18–29,52,54 investigated MRI evidence of a high intensity zone (HIZ) and we were able to pool 12 studies18–29 (Table 1). Pooling demonstrated informative +LRs (3.10; 95% CI: 2.27–4.25, I2 = 63.6%), but uninformative −LRs (0.61; 95% CI: 0.48–0.77, I2 = 92.2%) (Table 1).

Six studies22,25,30–32,74 investigated the MRI evidence of an annular fissure and we were able to pool five studies22,25,30–32 (Table 1). Pooling demonstrated informative +LRs (2.88; 95% CI: 2.02–4.10, I2 = 79.5%) and −LRs (0.24; 95% CI: 0.10–0.55, I2 = 90.3%) (Table 1).

Four studies15,18,24,25 investigated MRI evidence of Type 1 Modic changes and we were able to pool all 4 studies (Table 1). Pooling demonstrated informative +LRs (10.0; 95% CI: 4.20–23.82, I2 = 0.0%), but uninformative −LRs (0.84; 95% CI: 0.74–0.96, I2 = 89.2%) (Table 1).

Three studies15,18,25 investigated MRI evidence of Type 2 Modic changes and we were able to pool all 3 studies (Table 1). Pooling demonstrated informative +LRs (8.03; 95% CI: 3.23–19.97, I2 = 0.0%), but uninformative −LRs (0.88; 95% CI: 0.88–0.96, I2 = 65.8%) (Table 1).

Four studies33,35–37 investigated the centralisation phenomenon to identify discogenic pain and we were able to pool all four studies (Table 1). Pooling demonstrated informative +LRs (3.06; 95% CI: 1.44–6.50, I2 = 10.8%), but uninformative −LRs (0.66; 95% CI: 0.52–0.84, I2 = 57.9%) (Table 1).

Index tests for sacroiliac joint pain studies that could be pooled across at least 2 studies are presented below. Index tests investigated included a range of pain provocation tests (clinical examination) and bone scan.

Two studies38,39 investigated radionuclide imaging (i.e., bone scan) to identify the sacroiliac joint as a source of low back pain and we were able to pool both studies. Pooling demonstrated informative +LRs (7.33; 95% CI: 1.42–37.8, I2 = 0.0%), but uninformative −LRs (0.74; 95% CI: 0.41–1.34, I2 = 80.2%) (Table 1).

For clinical examination-based index tests to identify the sacroiliac joint our meta-analysis demonstrated informative +LR for the distraction test41,43 (2.18; 95% CI 1.08–4.38, I2 = 0.0%), but uninformative −LR (0.73; 95% CI: 0.54–0.99, I2 = 0.0%). Absence of midline low back pain37,45 demonstrated informative +LR (2.41 95% CI; 1.89–3.07, I2 = 0.0%) and −LR 0.35 (95% CI: 0.12–1.01, I2 = 75.6%). Pooling for all other index tests for the sacroiliac joint demonstrated that no test in isolation provided informative +LRs and −LRs (Table 1). Seven studies37,41–43,46–48 investigated a composite of pain provocation tests (3 or more positive sacroiliac joint provocation tests) and we were able to pool six studies.37,41,43,46–48 Pooling demonstrated informative +LRs (2.44; 95% CI: 1.50−3.98, I2 = 76.6%) and −LRs (0.31; 95% CI: 0.21−0.47, I2 = 0.0%) (Table 1).

Index tests for facet joint pain studies eval‎uated in two or more individual studies are presented below. Only one index test for the facet joint was able to be pooled. The remaining index tests are presented in Supplementary Appendix S6. Index tests presented below include imaging tests (SPECT—single-photon emission computed tomography), Revel's criteria (5 or more of 7 clinical characteristics: age ≥65, pain relieved by recumbency, pain not exacerbated by coughing, pain not exacerbated by extension/rotation, pain not exacerbated by forward flexion, pain not exacerbated by hyperextension, pain not worse with rising), paraspinal pain, midline spinal pain. Index tests investigated in single studies included a range of clinical examination findings, and clinical prediction rules (Supplementary Appendix S6).

Four studies56,58,60,77 investigated evidence of facet joint uptake on SPECT and we were able to pool three studies56,58,77 (Table 1). Pooling demonstrated informative +LRs (2.80; 95% CI: 1.82–4.31, I2 = 0.0%) and –LRs (0.44; 95% CI: 0.25–0.77, I2 = 7.0%) (Table 1).

Studies investigating Revel's criteria were not pooled due to heterogeneity in diagnostic values between studies.63,64,70,71 The diagnostic accuracy of Revel's criteria was inconsistent.63,64,70,71 Two studies70,71 found informative +LRs and −LRs and two other studies63,64 found uninformative +LRs and −LRs (Supplementary Appendix S6). None of the seven individual items comprising Revels criteria produced informative +LRs and −LRs in more than one study (Supplementary Appendix S6). Para-spinal pain and midline spinal pain both had uninformative +LRs and −LRs (Supplementary Appendix S6).

We also pre-planned sensitivity analysis to investigate the influence of the reference test quality on estimates of the diagnostic accuracy of index tests, by limiting the studies to those meeting our higher threshold for the reference test quality.

Five studies20,21,25,26,28 investigating HIZ met our criteria for a higher quality reference standard. When pooling only these studies20,21,25,26,28 the results demonstrated slightly higher informativeness for the +LRs (3.54; 95% CI: 2.03–6.20) compared to when pooling all studies regardless of the reference standard quality (+LR: 3.10; 95% CI: 2.27–4.25) (Table 1). The pooled −LR (0.48; 95% CI: 0.28–0.81) met our cut-off for informativeness unlike when all studies were pooled regardless of reference standard quality (−LR: 0.61; 95% CI: 0.48–0.77) (Supplementary Appendix S8).

Two studies46,48 investigating a combination of sacroiliac joint pain provocation tests met our criteria for a higher quality reference standard. When pooling only these studies46,48 the results demonstrated higher informativeness for the +LR (4.09; 95% CI: 2.53–6.60) compared to when pooling all studies regardless of reference standard quality (+LR 2.44; 95% CI: 1.50–3.98) (Table 1). The pooled −LR (0.17; 95% CI: 0.08–0.39) met our cut-off for informativeness unlike when all studies were pooled irrespective of reference standard quality (−LR 0.31; 95% CI: 0.21–0.47) (Supplementary Appendix S8). However, these results should be interpreted with caution due to the small number of studies.

We also performed sensitivity analyses post-hoc to examine the influence of risk of bias quality on estimates of the diagnostic accuracy of index tests by excluding studies with high risk of bias in each of the four domains of the QUADAS-2 scale. For a combination of sacroiliac pain provocation tests, removing studies of high risk of bias for the domain ‘patient selection’ reduced the +LR from 2.44 (95% CI: 1.50–3.98) to 1.69 (95% CI: 0.98–2.90) and for ‘reference standard’ increased the +LR from 2.44 (95% CI: 1.50–3.98) to 3.06 (95% CI: 1.75–5.33). For HIZ and the remaining domains for combination of sacroiliac joint pain provocation tests, the removal of studies with high risk of bias had little to no effect on the diagnostic accuracy values. Further details are presented in Supplementary Appendix S8.

Only one index test had more than ten studies in the meta-analysis to explore publication bias. No publication bias was found for the meta-analysis of the index test ‘MRI evidence of high intensity zone’ (12 studies) based on Deeks test (p = 0.53).

Discussion

We located 60 studies investigating the diagnostic accuracy of tests to identify the source of low back pain. To our knowledge this is the most comprehensive analysis of diagnostic tests for low back pain to date. Most studies focussed on the disc (35 studies) with fewer studies considering the facet joint (14 studies) or the sacroiliac joint (11 studies). We found evidence that some index tests had informative +LRs and −LRs for the disc and sacroiliac joint, and the facet joint. In studies of people with persistent pain, MRI findings of disc degeneration, HIZ, annular fissure, Modic type 1, Modic type 2, and uptake of facet joint on SPECT increased the likelihood of the disc being a nociceptive source of low back pain. The only informative physical examination-based index tests were a positive centralisation phenomenon to identify discogenic pain, and the absence of midline low back pain and a combination of sacroiliac joint pain provocation tests to identify sacroiliac joint pain.

In the previous review, MRI evidence of a high intensity zone and disc degeneration, and centralisation phenomenon were found to be informative to identify the disc as the source of low back pain and a combination of sacroiliac joint provocation tests were found to be informative to identify the SIJ as the source of low back pain.7 The results of our review reinforced the results of the previous review as a larger number of studies were able to be pooled. The previous review found there was no informative index tests to identify the facet joint as the source of low back pain, however the results of our review found that facet joint uptake on SPECT was informative.

Strengths of this study include using a sensitive search strategy and following a strict pre-specified protocol. Another strength is that we were able to pool a greater number of studies compared to the previous review resulting in more confidence in the results.7 A limitation of our review is that most studies included in our review included convenience samples of patients referred to tertiary settings for further diagnostic testing, despite testing index tests more commonly used in primary care. This sampling approach may inflate preval‎ence estimates, but it's impact on diagnostic accuracy of the index tests is unclear. Risk of bias was generally high for the domain ‘reference standard’ as most studies used a less strict criteria for a positive test, which may reflect the realities of how these tests are used in clinical practice. Approximately half of the studies in the other three domains demonstrated low risk of bias, which should provide clinicians with some confidence in our results. Our review found that 21 new studies investigating the source of low back pain have been published in the past 15 years. While this substantially increased the available evidence, some index tests still lack adequate evidence and demonstrate imprecise values to draw confident conclusions regarding diagnostic accuracy.

Our results challenge the dominant view in the low back pain field, that a pathoanatomical diagnosis is usually not possible and so the label non-specific low back pain should instead be used for most patients. Our review provides preliminary evidence that a diagnosis may be possible for a subgroup of patients with low back pain, potentially moving beyond the non-specific low back pain label. The ability to form a diagnosis in people with persistent low back pain is an important step towards developing new, more targeted, and specific treatment approaches. The pathology and causal mechanism driving Modic type 1 changes have, for example, been linked to bacterial infection, inflammation, and bone marrow oedema.78 For annular fissures, zones of granulation tissue have been proposed to be the causal mechanism driving discogenic low back pain.79 Treatments that aim to address these causes and mechanisms (e.g., antibiotics, Zoledronic acid or Denosumab for Modic type 1 changes) require much further research regarding their safety and effectiveness; however, these research approaches present an opportunity to develop targeted more effective treatments.

Our results align with a recent systematic review80 that investigated the diagnostic accuracy of clusters of pain provocation tests for the sacroiliac joint as the source of LBP. The review found similar LRs to our review for 3 or more sacroiliac joint provocation tests (+LR: 2.13; 95% CI: 1.20–3.90 and −LR: 0.33; 95% CI 0.11–0.72).80 The review also found a positive or negative test was associated with an increase or decrease in the probability of the sacroiliac joint being the source of pain.80 Our results challenge and support some of the clinical features that are thought to be associated with discogenic and SIJ pain. For example, a recent seminar in The Lancet6 advocated the MRI findings that our review showed were informative for discogenic LBP, but it also advocated clinical features which lack evidence of diagnostic accuracy. Our review will thus have value for informing clinical assessment of low back pain.

Studies investigating index tests with different thresholds or defined by different measures (e.g., disc degeneration) did not always make it clear which thresholds or definitions were being compared. It is possible this may have affected diagnostic accuracy values; however, these studies were reviewed independently by two reviewers (CSH, MJH, or CGM) to minimise errors. Possible sources of heterogeneity in our review could be from the population (e.g., were patients’ surgical candidates), healthcare setting (e.g., primary care verse secondary care), the index test performed, the reference standard, and methods of the study (e.g., defined thresholds for a positive test). Unfortunately, it was not possible to explore heterogeneity between studies due to a lack of data and studies that could be pooled in the analysis.

There is a need for more diagnostic research eval‎uating tests to identify the pathoanatomical source of low back pain. To date the diagnostic research has focussed on the facet joint, disc and sacroiliac joint as sources of low back pain, but other structures of the lumbosacral spine (e.g., muscles, fascia, ligaments and vertebral body)6 are potential nociceptive sources and there are treatments targeting these structures. As there are now informative tests for the disc, sacroiliac joint, and facet joint (only one test), it should be a priority to investigate whether patients judged to have these conditions based upon validated index tests have different prognoses or responses to treatment compared to patients considered not to have those conditions. Ultimately, the diagnoses based upon these index tests will only have utility if they predict prognosis or response to treatment. A related issue is how informative does a test need to be to justify shifting from generic treatment of cases of non-specific low back pain to more targeted treatments directed towards the structure putatively responsible for a patient's symptoms. This issue is of interest as the +LRs for the disc tests ranged from 2.20 to 10.00 and so yield quite different certainties in a particular diagnosis. Some of the index tests investigated in our review are continuous (e.g., disc degeneration) and the diagnostic accuracy may be influenced by the thresholds used to define a positive test. Future research should more carefully investigate the optimal thresholds for a positive test.

Not all patients with low back pain would potentially benefit from a pathoanatomical diagnosis as many acute cases settle rapidly with little or no formal treatment.81 The potential benefit is more likely to be seen in those patients with persisting low back pain where a pathoanatomical diagnosis may help select more targeted treatment. However even in this patient group it would be important to consider issues such as feasibility, access, and costs of the index tests, and of the resulting treatment approaches they would lead to.

A better understanding of the clinical value of these diagnostic tests will allow clinicians to be selective in which patients are most likely to benefit from further testing. Future research into the utility of these diagnostic tests is important as uncritical application may lead to unnecessary imaging, overdiagnosis, and ultimately, overtreatment. This is important as research has shown unnecessary testing can lead to increases in resources, costs, and negative downstream consequences.82 Some of the informative index tests included in this review require imaging (e.g., MRI or SPECT) which is accessible in some but not all countries. These imaging tests are reasonably expensive tests that may restrict access for many people, but if they inform management that aids recovery and return to work, they may be cost-effective. Other index tests include clinical examination tests such as those for SIJ pain, which are cheap but do require adequate clinical skills and training.

In conclusion, our review identified informative index tests to identify the disc, sacroiliac joint, and the facet joint as the source of LBP. This suggests it may be possible to diagnose a subgroup of patients with low back pain. A diagnosis may shift generic symptomatic treatments of non-specific low back pain to instead, more specific treatments targeted to the pathoanatomical source of low back pain. Our results challenge and support some of the diagnostic tests thought to be associated with discogenic and SIJ pain. Further high-quality primary studies are required to assess the clinical utility of these tests in guiding more targeted treatments and subsequently improving outcomes, ultimately to improve patient care.

Contributors

Conception of the study, drafting study protocol: All authors.

Acquisition of data: CSH, AT, SwS, SaS, SPC, CGM, MJH.

Analysis and/or interpretation of data: CSH, AT, JM, IAH, CGM, MJH.

Drafting the manuscript: CSH, AT, CGM, MJH.

Final approval of the manuscript: All authors.

Data sharing statement

The original data will be shared with researchers upon request.

Declaration of interests

We (author team) declare no competing interests.

Acknowledgements

CGM is funded by an NHMRC Research Fellowship (APP 1194283).

No other funding was provided to complete this study.

Appendix A Supplementary data (1)

Document (707.60 KB)

Supplementary material

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