Back Pain Doctor
Spondylolysis (Pars Stress Fracture)
Written by Dr Joshua Hatch, Musculoskeletal GP, RACGP Fellow, Diploma in Musculoskeletal Medicine (FSEM UK).
Spondylolysis is a stress fracture through the pars interarticularis, the narrow bridge of bone connecting the upper and lower facet joints and the weakest part of a lumbar vertebra. It develops from repetitive loading of the lower back into extension, which is why it clusters in adolescent athletes in gymnastics, cricket fast bowling, the football codes, dancing and weightlifting. Where the bone is sufficiently weakened, the vertebra can slip forward on the one below (a spondylolisthesis), which most often happens during an adolescent growth spurt. Many people have no symptoms at all and the finding turns up incidentally on an X-ray taken for another reason.
Assessment focuses on separating this from ordinary mechanical back pain, because the two are managed differently and a missed pars injury can progress. The history usually gives it away: a young athlete, an extension-loaded sport, and activity-related pain that has persisted for weeks. Examination looks at spinal movement, hamstring length, gait and neurological function. Unlike adult non-specific low back pain, where routine early imaging is discouraged, persistent activity-related back pain in a young athlete does warrant imaging, usually MRI, which detects pars injury before it appears on X-ray and avoids the radiation exposure of CT in this age group.
First-line care is usually a period away from the aggravating sport to allow a recent fracture to heal, simple analgesia, and physiotherapy to restore hamstring flexibility and build trunk and back strength. A brace is sometimes used, and helps most in athletes whose pain came on acutely rather than those with longstanding symptoms. Periodic imaging checks that the vertebra is not shifting. Surgery is reserved for high-grade or progressive slips, nerve compression, or pain that has not settled despite thorough non-surgical management. Management works best coordinated between the GP, physiotherapist and, where needed, a sports physician or spinal specialist. Leg weakness, numbness, or any change in bladder or bowel function needs prompt assessment.
This page is general educational information and does not replace individual medical advice. Anyone with concerns should speak with their GP.
Common symptoms
- Low back pain in a teenager that worsens with sport and eases with rest
- Pain provoked by arching backwards or by repetitive extension and rotation
- Pain that may radiate into the buttocks or backs of the thighs
- Tight hamstrings, back stiffness or a stiff-legged walking pattern
Commonly seen in
Evidence for twelve treatment options in spondylolysis (pars stress fracture)
This is not a fixed ladder or a package of treatments. Every option is assessed independently against this diagnosis, including treatments with limited direct research that may still be reasonable for a clearly defined tissue target. The evidence level, likely benefit, risks, cost and alternatives are weighed at consultation.
Foundation: diagnosis, education and rehabilitation
The part of care with the broadest relevance. For many people it is enough on its own; other options are judged against it, not automatically added after it.
Diagnosis, education and progressive rehabilitation Working out what is driving the pain, explaining what your imaging does and does not mean, and building a graded loading plan you can actually follow. Core care
What it involves
Assessment to identify the likely pain source, an explanation of what the diagnosis means, adjustment of the loads that aggravate it, and a progressive strength and conditioning plan, with weight management where that is clinically relevant.
What the evidence shows
Load is what builds bone; nothing else offered here does. A meta-analysis of 80 studies and 5,581 postmenopausal women found exercise improved bone mineral density at the lumbar spine, femoral neck and total hip, and that supervision was not required for the effect (Mohebbi, Osteoporos Int 2023). A network meta-analysis of 97 trials found every exercise type beat no exercise at the femoral neck, with resistance training ranking best for total hip (Zhang, J Clin Nurs 2021). Moderate-to-high impact loading also improves bone structure, not just density, and the effect is site-specific. It accrues where the load is applied (Ng, J Bone Miner Res 2023).
Pairing reviewed 2026-09-02.
Where it fits
For a bone stress injury the sequence is relative rest until it settles, then a graded return to load that is progressed slowly enough for the bone to keep up. For bone density, the loading is the treatment and it has to continue. The gains reverse when it stops. Energy availability, vitamin D and medical contributors are assessed alongside it.
Muscle and symptom-modifying options
Useful only when the examination identifies the tissue they target or when short-term pain control creates a useful rehabilitation window.
Wet needling and trigger point injection (trigger point injection) A fine needle into a tender band of muscle, with a small volume of dilute glucose solution injected through it. Only if relevant
What it involves
The needle is placed into the tender muscle band and a small volume of 5% glucose with a very dilute local anaesthetic (0.02-0.08%) is injected. Often done in the same visit as your assessment, and usable where the tender area sits deeper. Dry needling (the same technique with nothing injected) is not offered here.
What the evidence shows
No trial evidence in pars stress injury. Protective paraspinal muscle guarding is common alongside the bone injury and is treated as muscular pain.
Pairing reviewed 2026-08-30.
Where it fits
Occasionally used for secondary muscular pain once the diagnosis and the loading plan are settled. It does not treat the fracture.
Ultrasound-guided injections Guidance means the needle can be seen reaching the target. What goes into the needle depends on the diagnosis. Only if relevant
What it involves
The injection is performed under ultrasound so the needle can be watched into the target structure. What is injected is decided by the diagnosis, and corticosteroid is used sparingly, for the reasons set out below.
What the evidence shows
Injection has no role in bone healing, and corticosteroid is generally avoided around a healing stress injury. An image-guided injection is occasionally used diagnostically in established, long-standing pars defects where the source of pain is genuinely unclear.
Pairing reviewed 2026-08-30.
Where it fits
Not part of treating the fracture. Used only as a diagnostic step in selected chronic cases.
V-ACTOR vibration therapy (vibration therapy) Low-frequency vibration applied over tender muscle. Not a shockwave, despite sharing the machine. Not offered for this
What it involves
A vibration handpiece is moved over the tender muscle and fascia for a few minutes. It runs from the same STORZ MASTERPULS icon console as radial shockwave but is a separate handpiece delivering a different, gentler form of energy. No needles, no anaesthetic, no downtime.
What the evidence shows
Vibration applied over a healing bone stress injury is not appropriate, and there is no study supporting it here.
Pairing reviewed 2026-08-30.
Where it fits
Not used for a pars injury.
Energy-based treatment options
Radial pressure wave, focused shockwave and EMTT have different targets and different evidence. They are assessed separately rather than treated as one category.
Radial or focused shockwave? Read the overviewRadial shockwave (radial pressure wave) Broad treatment across tender muscle and fascia, close to the surface. Not offered for this
What it involves
A handpiece is moved over the tender tissue while ballistic pressure pulses are delivered, using a transmitter head chosen for the tissue, including heads shaped for fascia and for the muscle either side of the spine. The pulse is strongest at the skin and weakens with depth, so this is mainly a myofascial treatment, though it can reach deeper in some areas. No anaesthetic, no downtime, usually a course of sessions about a week apart.
What the evidence shows
Radial pressure waves lose energy within the first few centimetres of tissue. The pars sits deep to the paraspinal muscles, beyond useful radial penetration. Focused shockwave is the device that reaches that depth and the one that carries the bone-healing literature, so where shockwave is discussed at all for this injury it is focused, not radial.
Pairing reviewed 2026-08-30.
Where it fits
Not used for a pars injury. See focused shockwave above.
Focused shockwave (ESWT) A true shock wave converging at depth: for tendon, joint, ligament and bone. Plausible: no studies
What it involves
A focused system generates an acoustic shock wave that converges at a focal point set at a defined depth, concentrating the energy where the target is. This is the form used for tendon, joint, ligament and bone. Typically four to six sessions about a week apart, no anaesthetic and no formal downtime.
What the evidence shows
No study of shockwave aimed at a pars defect was found. Search on 2026-10-22: PubMed, shockwave terms with spondylolysis, pars interarticularis, pars defect, spondylolisthesis or scoliosis (10 records, all read), with a trial and systematic-review pass. The one report that touches it is a 69-year-old with a slip and pars defects whose radial shockwave went to the buttock and thigh muscles within nine months of mixed care, so its effect cannot be separated out (Chu, Cureus 2026). The shockwave bone literature is in long bones: 73% union across 1200 long-bone non-unions on systematic review (Sansone, J Clin Med 2022), and equivalence with surgery for hypertrophic long-bone non-union in a randomised trial of 126 patients (Cacchio, JBJS Am 2009), with a small series in resistant stress fractures in athletes (Taki, Am J Sports Med 2007). A Cochrane review of acute fracture found only one shockwave trial and rated the evidence very low certainty (Searle, Cochrane 2023). None of that has been tested at the pars, which is a different bone in a different loading environment.
Pairing reviewed 2026-10-22.
Where it fits
Not part of the standard plan. Where shockwave is considered at all for an established pars non-union (after an adequate trial of activity restriction and rehabilitation) focused is the appropriate device: it is the one with the bone-healing literature behind it, and the only one that reaches the depth of the pars. The gap in the evidence is explained before any such conversation.
EMTT (magnetotransduction therapy) High-energy magnetic pulses applied over the area. Usually painless, no contact. Plausible: no studies
What it involves
You sit with the applicator positioned over the area for a short session. It is usually painless and needs no gel or skin contact. It is usually given as a course, commonly alongside shockwave.
What the evidence shows
There are no published randomised trials of EMTT in this condition, or in any musculoskeletal condition, that could be identified. The supporting work is laboratory work: EMTT increased tenocyte proliferation, migration and collagen expression in cultured human tendon cells (Mancini, Int J Mol Sci 2025). The nearest human evidence for a related electromagnetic therapy is negative. A randomised trial of pulsed electromagnetic field therapy added to eccentric exercise for Achilles tendinopathy found no improvement in outcome scores or tendon neovascularity over eccentric exercise alone (Ko, Orthop J Sports Med 2024).
Pairing reviewed 2026-08-30.
Where it fits
Not part of managing a bone stress injury. Offered only as an adjunct alongside treatment that does have evidence, never as the plan itself, and only after that gap is explained. Much of the EMTT literature is manufacturer-affiliated, which is part of why it is described this way.
Biologic and joint injection options
Each injection is assessed independently for the named diagnosis. Cost, uncertainty, likely benefit, risks and alternatives are part of the decision.
Platelet-rich plasma (PRP) Your own blood, concentrated and injected under ultrasound guidance. Plausible: no studies
What it involves
Blood is taken from your arm, spun to concentrate the platelets, and injected into the target under ultrasound guidance in the same appointment.
What the evidence shows
No clinical study of any kind was found. A PubMed search on 11 October 2026 pairing platelet, platelet-rich, bone marrow aspirate and orthobiologic terms with spondylolysis, pars interarticularis, pars defect, pars fracture, pars stress and pars repair returned no records, and a second search using the abbreviation PRP returned four, none of them about a pars injury. There is nothing to report in either direction: no benefit shown and no harm described.
Pairing reviewed 2026-10-11.
Where it fits
Not part of managing a pars stress injury. Time away from extension and impact loading, then a graded return through rehabilitation, is the treatment, and nothing published suggests an injection would add to it.
Prolotherapy (dextrose) A course of dextrose injections into and around the structure and its attachments. No study in this condition
What it involves
Hypertonic dextrose is injected at the tender ligament and tendon attachments, and into the joint where relevant, usually as a series of treatments a few weeks apart.
What the evidence shows
No study of prolotherapy for a pars stress injury or defect. PubMed searches on 16 October 2026 (prolotherapy, dextrose or hypertonic glucose with spondylolysis, pars interarticularis or spondylolisthesis, 10 records; then prolotherapy with spondylolisthesis, pars or spinal instability, 1 record) found no trial, series or case report in this condition. Spondylolisthesis appears only as a listed cause of back pain in a review of prolotherapy for low back pain (Mociu, Medicina 2025).
Pairing reviewed 2026-10-16.
Where it fits
Not part of managing a healing bone stress injury, which an injection into ligament cannot repair. Load management and progressive rehabilitation lead.
Viscosupplementation (hyaluronic acid) A gel-like injection into an arthritic joint. Widely used, and genuinely contested. Not offered for this
What it involves
One or a short series of hyaluronic acid injections into the joint under ultrasound guidance.
What the evidence shows
A treatment for an arthritic peripheral joint, with no application to a stress fracture.
Pairing reviewed 2026-08-30.
Where it fits
Not used for this condition.
Nerve-targeted options
Relevant when examination identifies a superficial neuropathic pattern or a compressed peripheral nerve, not simply because pain is present.
Lyftogt perineural therapy (perineural injection therapy) A series of small dilute dextrose injections just under the skin, over tender superficial nerves. Plausible: no studies
What it involves
Small injections of low-concentration dextrose, usually 5%, placed just beneath the skin along tender superficial nerves. Given as a series of short sessions.
What the evidence shows
No study of perineural injection in spondylolysis (pars stress injury) was found. Searching perineural injection, neural prolotherapy, subcutaneous and perineural dextrose, glucopuncture, Lyftogt and neurofascial terms against spondylolysis, spondylolisthesis, the pars interarticularis and stress fracture, with separate passes for randomised trials and systematic reviews, returned no study in this condition.
Pairing reviewed 2026-11-04.
Where it fits
Not part of managing this condition.
Ultrasound-guided nerve hydrodissection Fluid placed around a nerve to free it from the surrounding tissue. Trapped nerve, not the pars
What it involves
Under ultrasound, fluid is placed in the plane around the nerve to separate it from the tissue that is tethering or compressing it.
What the evidence shows
No study of hydrodissection for spondylolysis was found, and it does not act on the bone. Two case reports bear on it indirectly. A 14-year-old girl with an L5 pars defect on imaging turned out to have her pain from superior cluneal nerve entrapment: a steroid injection over the iliac crest relieved it, one over the pars defect did not, and she reported at least 90% improvement after surgical release of the nerve (Ruan, J Am Acad Orthop Surg Glob Res Rev 2023). Separately, a 41-year-old man with a slow-to-heal stress fracture of a lumbar transverse process (a different part of the vertebra) had an 80% immediate and 95% sustained fall in pain after three weekly ultrasound-guided 5% dextrose hydrodissections, with the fracture healing on follow-up imaging (Yoon, Cureus 2025). Neither is a pars stress injury treated with hydrodissection, and single cases cannot show cause.
Pairing reviewed 2026-11-04.
Where it fits
Not a treatment for the pars injury. Considered only where assessment finds a trapped nerve, such as the superior cluneal nerve, contributing to the pain.
This is general information only and suitability is assessed individually. Treatments with limited or condition-dependent evidence may still be discussed, but only with clear explanation of the uncertainty, the expected benefit, risks, cost and alternatives. Red flags, progressive neurological symptoms or suspected serious pathology require a different pathway.
Every treatment above is described in full on the non-surgical treatments page, including what each one is used for and what the evidence supports. Ratings apply to the named diagnosis; an adjacent muscle, tendon, joint or nerve problem is assessed as a separate target. The method behind the ratings, and the treatments not offered, are set out on the evidence page.
Corticosteroid injection is reviewed separately for each diagnosis.
Cortisone reliably reduces pain in the short term, and that can be genuinely useful when pain is stopping you sleeping or moving enough to rehabilitate. Beyond that window the picture changes. A systematic review of 41 randomised trials and 2,672 participants found that corticosteroid injection reduced pain in the short term but that the effect reversed at intermediate and long term; in pooled analysis for lateral epicondylalgia the short-term effect was large (SMD 1.44, 95% CI 1.17 to 1.71) while no intervention was favoured at 26 weeks (-0.40, -0.67 to -0.14) and at 52 weeks (-0.31, -0.61 to -0.01) (Coombes, Lancet 2010). In a randomised trial in lateral epicondylalgia, 83 per cent of the corticosteroid group had completely recovered or much improved at one year against 96 per cent given a placebo injection, and recurrence ran at 54 per cent against 12 per cent; adding physiotherapy made no significant difference at one year (Coombes, JAMA 2013). In joints, repeated corticosteroid injections have been associated with cartilage loss. It does not repair anything.
So treatment plans are not built around it. Where an injection is the right call, the specific diagnosis and target are reviewed, what is being injected and why is discussed, the number is kept low, and it is paired with the loading work that changes the longer-term course.
When it might still be considered
- Pain severe enough to block rehabilitation
- A clear inflammatory or bursal target on imaging
- A specific short-term goal: a trip, a procedure, a return to work
- Diagnostic use, where the response shows where the pain is coming from
When a cortisone injection is worth doing, and when it is not
Other back conditions
Pain in the same area can come from more than one source, and the label matters less than what the examination and history point to. These are the other guides for this region.
Frequently asked questions
Which young athletes are most at risk?
How is it different from spondylolisthesis?
Can my child return to sport?
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