Lumbar Disc Herniation

«Understanding the condition (definition, symptoms, epidemiology, stages, absolute surgical indications)» slot — content in preparation.

«How surgery and SART complement each other» slot — content in preparation.

These are the evidence candidates assigned to this topic. The citations to be used are finalised by the author when the page is published.

• EV-005★★★★★L1 · Systematic review / meta-analysis

  A substantial proportion of herniated discs resorb spontaneously, so they are not automatically surgical targets

  Spontaneous resorption of lumbar disc herniation is common, with an overall resorption rate reported at roughly 66%.

  2025 · Meta-analysis of spontaneous resorption rates (Nature Scientific Reports, 2025 and others)

  Limitation — The exact PMID and figures still need to be confirmed.

• EV-071★★★★★L1 · Systematic review / meta-analysis

  Spinal manipulative therapy produces effects comparable to other standard care in chronic low back pain, and is safe

  A Cochrane systematic review found spinal manipulative therapy (SMT) to produce effects and safety comparable to other recommended treatments for chronic low back pain.

  Rubinstein SM (2019) · Benefits and harms of spinal manipulative therapy (BMJ 2019, Cochrane)

  Limitation — This is evidence for SMT in general, not a validation of any specific SART technique.

• EV-050★★★★L2 · Randomised controlled trial / prospective cohort

  In low back pain the anticipatory (feedforward) activation of the deep stabilisers is delayed or lost

  Normally transversus abdominis and multifidus activate in advance of limb movement (feedforward) to lock the spine. In low back pain that anticipatory activation is delayed and the deep muscles become inhibited and atrophic.

  Hodges PW (1996) · Inefficient muscular stabilization of the lumbar spine (1996) and related work

• EV-079★★★★L2 · Randomised controlled trial / prospective cohort

  Much discogenic pain centralises and improves with movement in a specific direction (extension)

  In discogenic low back pain, repeated extension movements draw pain radiating into the leg back towards the midline (centralisation) and improve it — the concept of directional preference, developed into a self-treatment system (MDT).

  McKenzie R · Treat Your Own Back; the MDT research literature

• EV-004★★★L3 · Retrospective cohort / case-control / cross-sectional

  In spinal pain the deep stabilising muscles are neurologically inhibited and undergo structural change

  In low back pain patients the deep stabilisers such as multifidus show reduced cross-sectional area, fatty infiltration and neurological inhibition. Under fixation the brain's protective command drives the deep muscles into hypertonicity or loss of function (segmental facilitation).

  Korr IM; Hodges P et al. · Korr IM (segmental facilitation); Hodges P et al. (core stability, multifidus); MRI studies on multifidus fatty infiltration

  Limitation — Quantitative recent imaging papers (with PMIDs) on multifidus fatty infiltration still need to be added.

• EV-006★★★L3 · Retrospective cohort / case-control / cross-sectional

  If decompression surgery leaves the structural cause in place, the problem recurs

  After single-level lumbar discectomy, recurrence at the same level is reported at roughly 5–24% and is the most common reason for revision surgery. Recurrence risk rises with high spinal loading or with premature return to heavy load (cohort of 942 patients).

  2023 · Recurrence-rate reviews (2023–2025); loading-and-recurrence cohort (PMC9288683, 2022)

  Limitation — PMIDs still need to be confirmed.

• EV-007★★★L3 · Retrospective cohort / case-control / cross-sectional

  Malalignment concentrates load on particular discs and drives degeneration

  Left–right asymmetry produces uneven loading of the vertebrae, which sets up a vicious cycle of muscle atrophy and overload leading to disc degeneration (cadaveric study). As sagittal malalignment increases, lumbar disc loading rises and deformity worsens in a self-reinforcing loop (musculoskeletal model). Alignment parameters such as pelvic incidence and sacral slope correlate with disc and facet pathology (systematic review).

  PMC12632278 (cadaveric); PMC9779485 (musculoskeletal model); PMC11959076 (systematic review) · PMC12632278 (cadaveric); PMC9779485 (musculoskeletal model); PMC11959076 (systematic review)

  Limitation — Bibliographic details still need to be confirmed.

• EV-061★★★L3 · Retrospective cohort / case-control / cross-sectional

  Discs rehydrate and recover when load is reduced, but uncontrolled decompression is harmful

  Under the microgravity exposure of spaceflight, disc height and volume increase (rehydration), yet decompression that occurs rapidly and without control raises the risk of herniation and injury.

  Belavý DL (2016) · Disc herniations in astronauts (2016) and related work

• EV-062★★★L3 · Retrospective cohort / case-control / cross-sectional

  Imaging confirms that traction actually reduces the size of a herniated disc

  CT confirmed a reduction in the size of herniated discs under lumbar traction.

  Onel D · Computed tomographic investigation of traction effect

• EV-067★★★L3 · Retrospective cohort / case-control / cross-sectional

  Compressed it bends, distracted it straightens — the direction of load governs deformity

  Quantified the effect of immediate vertical unloading on spinal alignment and the disc, showing axial load to be a direct driver of deformity.

  Cheung JPY · The effect of immediate vertical unloading

• EV-072★★★L3 · Retrospective cohort / case-control / cross-sectional

  Prone lumbar traction produces clinical improvement in patients with discogenic pain

  Improved outcomes were reported in patients with discogenic low back pain following a prone lumbar traction programme.

  Beattie PF (2008) · Outcomes after a prone lumbar traction

• EV-070★★L4 · Cadaveric / biomechanical model / basic experiment

  Lumbar lordosis must be maintained for disc pressure to be distributed evenly

  A load-distribution model showing that when lumbar lordosis is maintained, pressure is spread evenly across the disc, and that when lordosis is lost, pressure concentrates in particular regions.

  Müller A (2021) · Load distribution in the lumbar spine

• EV-001★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  Discs fail under torsion and rotational shear, not under compression

  The fibres of the lumbar annulus fibrosus run in alternating oblique layers, so when the spine rotates only half of the fibres take tension while the rest slacken, halving the tissue's capacity to resist. The annulus is therefore strong in compression but vulnerable to torsion. When the facet joints fail to check rotation, that rotational load is transferred into the disc and tears it (the three-joint complex).

  Farfan HF (1973) · Mechanical Disorders of the Low Back

• EV-002★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  Fixation of one segment drives compensatory hypermobility in the adjacent segment, and the neutral zone expands asymmetrically into pain and deformity

  Spinal stability is maintained by three cooperating systems: passive (bone, ligament, disc), active (muscle) and neural control. After injury or degeneration it is the neutral zone — the early range that moves with little resistance — rather than total range of motion that enlarges abnormally, and that loosened zone becomes the pain generator. When a fixated segment stops moving, adjacent or vulnerable segments over-compensate and their neutral zones widen.

  Panjabi MM (1992) · The stabilizing system of the spine I·II (1992); Clinical spinal instability and low back pain (2003)

• EV-013★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  Pain generators are identified through anatomy and innervation, not guesswork

  Precise clinical anatomy of the lumbar and cervical spine, with identification of pain generators (facet joints, intervertebral discs, nerve roots), including referred-pain maps for the upper cervical spine (the C4 reference).

  Bogduk N · Clinical Anatomy of the Lumbar Spine and Sacrum

• EV-024★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  The spinal cord and nerves are placed under physical tension as the body flexes and extends

  The spinal cord and nerve roots are physical tissues that lengthen and tension with spinal posture (adverse mechanical tension). Malalignment therefore imposes mechanical tension on neural tissue.

  Breig A · Adverse Mechanical Tension in the Central Nervous System

• EV-029★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  The lumbar spine is damaged by repeated flexion and torsion, and neutral must be preserved

  An injured lumbar spine is made worse by repeated flexion and extension and by cumulative load (spine sparing). The combination of flexion and torsion is central to annular damage.

  McGill S (2002) · Low Back Disorders

• EV-049★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  Sensitisation of the nervous system amplifies pain, and pain is not proportional to tissue damage

  Introduced mechanical sensitivity of the nervous system and central sensitisation into clinical practice. Pain is a product of the nervous system's threat appraisal rather than of the quantity of tissue damage.

  Butler D (2000) · The Sensitive Nervous System

• EV-077★★L4 · Cadaveric / biomechanical model / basic experimentfoundational

  The pressure borne by the disc varies markedly with posture (sitting exceeds standing)

  Direct in vivo measurement of lumbar intradiscal pressure across postures. Sitting — and especially sitting in forward flexion — raises disc pressure substantially above standing.

  Nachemson A (1960) · Lumbar intradiscal pressure

• EV-015★L5 · Expert opinion / classical theory / mechanistic hypothesisfoundational

  The vulnerable segment beside a fixated one compensates by moving too much (relative flexibility)

  Rather than moving a stiff segment, the body moves the adjacent flexible segment excessively, and damage accumulates there (movement impairment syndromes, relative flexibility).

  Sahrmann S · Diagnosis and Treatment of Movement Impairment Syndromes

• EV-022★L5 · Expert opinion / classical theory / mechanistic hypothesisfoundational

  In every joint, geometric angle determines movement

  The geometry of the joint surfaces determines the direction of movement and the automatic rotation of that joint. This is the normal physiology that pairs with Farfan's account of failure.

  Kapandji AI (1974) · The Physiology of the Joints, Vol 3