Ross Hauser, MD; Danielle Matias, PA-C; Demi Foster, APRN

Persistent low back pain can make sitting, walking, bending, and sleeping difficult. Some people have pain mainly in the back. Others also experience hip, buttock, or leg symptoms. A scan may show disc degeneration or arthritis, yet it may not explain why a particular movement hurts or why earlier treatment did not help.

At Caring Medical, our clinical interest includes the supporting ligaments of the lumbar spine and pelvis. These tissues can contribute to pain and abnormal movement in selected patients. However, low back pain has multiple possible causes, and ligament instability should not be assumed to explain every case.

This article examines Prolotherapy, its proposed mechanisms, and the evidence for different spinal injection approaches. Two new 2026 papers add useful information: a systematic review of chronic spinal pain and a randomized comparison of dextrose Prolotherapy with epidural steroid injections. We also retain the earlier studies, patient cases, and practical learning points that help explain what the results mean.

What can cause low back pain and associated leg pain?

The lumbar spine relies on discs, facet joints, ligaments, muscles, and nerves working together. The sacroiliac joints connect the sacrum to the pelvis. Problems affecting these structures may overlap, making it difficult to identify a single pain source.

Our published review discusses spinal ligaments as a possible contributor to lumbar instability. Ligaments provide passive restraint; muscles provide active control. Injury or degeneration could alter load distribution and increase stress on other structures. This is a clinical and biomechanical explanation, rather than proof that most back pain begins with ligament damage. (1)

Potential contributors include:

• Disc-related pain, including some annular tears or herniations.
• Painful facet joints and their surrounding capsules.
• Sacroiliac joint or ligament-related pain.
• Tendon or ligament attachment pain, called enthesopathy.
• Nerve irritation or compression, sometimes accompanied by weakness or altered sensation.
• Hip disease, muscle-related pain, or other pelvic conditions.

Leg pain also needs clarification. Referred pain is felt away from its source without necessarily reflecting a compressed nerve root. Radicular pain involves irritation of a spinal nerve root. Neither the location of pain nor the presence of a disc bulge alone establishes the diagnosis.

An MRI finding is one part of the explanation

A systematic review of 3,110 people without symptoms found that disc degeneration and bulging were common and increased with age. This does not make MRI unhelpful; it means findings need to correspond with symptoms and examination results. (2)

An MRI may reveal a clinically important nerve compression, fracture, or other abnormality. It cannot, on its own, determine whether every visible degenerative change is painful or whether a soft-tissue injection is appropriate.

What is Prolotherapy intended to do?

Dextrose Prolotherapy uses a sugar solution injected into selected musculoskeletal tissues. Hypertonic dextrose is more concentrated than ordinary body fluids. Proposed effects include a local tissue response that may stimulate collagen production and affect painful connective tissues.

Lower-concentration dextrose has also been studied for pain-modulating effects. Rapid relief after an injection cannot reasonably be explained by new ligament growth occurring within minutes. Biological repair and changes in pain signaling are different proposed mechanisms. (3)

The goal of treating a painful attachment is to address the area where a ligament or tendon meets bone, sometimes called the fibro-osseous junction. This differs from injecting into a disc or the epidural space around spinal nerves. The location and purpose of the injection matter as much as the name of the treatment.

Dextrose, PRP, and cell-based preparations are different treatments

Our original article discussed several approaches within regenerative injection medicine. These distinctions remain important:

Our lumbar review discusses dextrose and PRP approaches, but does not establish that one is best for all patients or that every preparation reverses degeneration. (1)

For additional background, see our discussion of platelet-rich plasma for lower back pain.

New 2026 randomized trial: Prolotherapy versus epidural steroid injections

A pragmatic randomized trial analyzed 104 participants with low back and associated leg pain lasting at least 12 weeks and leg pain rated at least 6 out of 10. Fifty-five received dextrose Prolotherapy and 49 received epidural steroid injections. Up to five monthly Prolotherapy treatments or three monthly steroid injections were allowed. (4)

The adjusted average results favored Prolotherapy at six and twelve months after treatment completion:

Lower scores indicate better outcomes. (4)

This supports consideration of Prolotherapy for selected patients, but the trial was unblinded and treatment schedules differed. Average pain persisted in both groups. No adverse events were reported. The trial does not establish ligament regeneration, compare Prolotherapy with surgery, or prove it is preferable for every cause of leg pain. (4)

New 2026 systematic review: What the broader spinal evidence shows

A systematic review included 12 studies: three randomized trials and nine nonrandomized studies. Conditions included chronic low back pain, sacroiliac pain, disc-related pain, coccydynia, persistent pain after back surgery, and lumbar disc herniation with associated symptoms. Most studies reported improvements in pain, function, or quality of life. (3)

However, the review summarized results descriptively without pooling them statistically. Small samples and differences in diagnosis, injection site, concentration, and follow-up limit generalization. Its search ended in June 2025, so the April 2026 randomized trial provides evidence outside that search period. (3)

The review discusses ligament, joint, intradiscal, and epidural injections. These should not be treated as interchangeable procedures. Its observations about longer relief with higher concentrations do not establish a universal dose-response relationship: concentration was intertwined with different conditions and injection targets. Neither pain relief nor absence of reported major complications proves tissue regeneration or excludes rare risks. (3)

What earlier controlled trials found—and why they still matter

New favorable results should be considered alongside studies that found limited or no added benefit.

A foundational review included five controlled studies with 366 participants. Three trials found that Prolotherapy injections alone were not more effective than control injections. Two reported benefit when injections were combined with manipulation, exercise, or other treatments, but those additional interventions made it difficult to isolate the injections’ effects. (5)

A 2023 randomized trial assigned 38 patients to conservative treatment or a glucose-injection group. Both improved during follow-up, and the investigators concluded that no overall effects were attributable to the glucose component or the Prolotherapy protocol. It therefore does not establish that injections added benefit or that improvement demonstrated ligament repair. (6)

These findings differ from the favorable 2026 comparison with epidural steroid injections. Differences in participants, treatments, and comparators help explain why one result cannot settle every question about chronic low back pain.

A 654-patient report using 5% dextrose

A report published online in 2021 evaluated 2,382 people with low back pain or lumbar disc herniation and included 654 for treatment. The authors used diagnostic injections in patient selection and treatment sessions separated by four or six weeks. Average pain scores decreased from 7.2 before treatment to 0.9 at 52 weeks; 620 patients were classified as improved and 34 as having poor results. (7)

The size of this series is noteworthy, but it lacked a randomized control group. Its 94.8% improvement figure is an outcome in a selected population, not a success rate that can be promised to another patient. Selection, concurrent care, and symptom changes over time may influence results.

The report also described pain decreasing to 5.1 after the diagnostic injection. That response should not be equated with confirmed ligament healing or an established predictor for every Prolotherapy approach. The study’s 5% solution and technique also cannot be substituted directly for higher-concentration joint or ligament protocols. (7)

Caring Medical’s published lumbar review and three patient cases

Our published lumbar review presents a clinical perspective on instability and includes individual treatment examples. It is a review with case illustrations, rather than a randomized trial. Cases can show how symptoms and function changed, but cannot establish effectiveness for a wider population. (1)

Case 1: Longstanding back and lateral hip pain

A 78-year-old woman with six years of pain received five injection sessions addressing the spine and left gluteal tendon. Pain decreased from 8/10 to 1–2/10 at two months. At one year, she reported walking without a cane and no pain-medication use. (1)

Case 2: Sacroiliac pain after lumbar surgery

A 67-year-old woman had six months of left sacroiliac pain after lumbar laminotomy. Three sessions of combined Prolotherapy and PRP addressed the SI region. Sitting improved, although pain remained approximately 3–4/10 at three months. (1)

Case 3: Different responses in the back, hip, and legs

An 83-year-old man had five years of back and bilateral leg symptoms. A caudal epidural relieved leg symptoms but left back and hip pain. After six dextrose-and-PRP sessions, he stopped using his walker; back pain was 2/10 at eleven months. (1)

These cases involved combined treatments and selected individuals. They do not isolate dextrose’s contribution. The third case also illustrates that relief of one symptom does not necessarily resolve every coexisting pain source.

Facet joints, ligament attachments, and persistent pain after surgery

Facet joints guide movement between neighboring vertebrae. Their capsules and nearby ligaments help restrain motion. Our clinical perspective considers whether painful supporting tissues contribute to symptoms, but facet pain is not synonymous with instability and instability is not the only explanation for persistent pain.

Our separate article discusses facet joint osteoarthritis and facet arthropathy. Conventional approaches can include medication, rehabilitation, selected injections, diagnostic blocks, or radiofrequency procedures. Each addresses different aspects of pain; it is inaccurate to describe all conventional treatment as merely masking a single ligament problem.

A 35-patient randomized crossover study examined painful enthesopathies, or ligament/tendon attachment disorders. Eighty-six percent had undergone prior lumbar surgery. It compared local anesthetic with anesthetic plus a phenol-glycerol proliferant. Clinical assessments favored the proliferant injections, but relief generally lasted a few months rather than being permanent. (8)

This was not a dextrose or PRP trial, and it does not demonstrate that all postoperative pain is ligament-related. Its value is in showing that painful attachment sites may deserve attention in selected patients, including some with persistent pain after surgery. (8)

For a broader discussion, see causes and treatments of failed back surgery syndrome.

Disc-related pain: Injections inside a disc differ from ligament injections

A 2006 prospective series studied intradiscal dextrose injections in patients with advanced disc degeneration and leg pain, with or without back pain. Participants had been selected using discography and earlier treatment response. About 43.4% achieved sustained improvement; the average pain reduction among those responders was 71% at eighteen months. (9)

The 71% figure was not the average improvement for every participant. This uncontrolled study also does not establish disc regeneration. Injecting inside a disc is anatomically and procedurally different from treating ligament attachments, with a different risk profile. (9)

A separate retrospective series of 21 patients with MRI-confirmed degeneration examined fluoroscopy-guided injections to lumbar and pelvic supporting tissues. Eighteen reported at least 70% improvement in pain and function at one year, while two reported no benefit and one worsened. The small sample, incomplete follow-up information, and lack of a control group limit conclusions. (10)

A four-case clinical report also described substantial improvement after ligament injections, including return to activities or work. Such reports can generate useful questions, but accompanying treatments and the absence of controls prevent reliable estimates of treatment success. (11)

The important distinction is between treating symptoms associated with degeneration and proving that a degenerated disc has been repaired.

What does the PRP evidence add?

A systematic review and meta-analysis included three randomized PRP trials with 131 participants. It reported improved short-term pain and satisfaction compared with controls. These findings support further study of PRP for selected low-back conditions, but the small evidence base and varying treatment targets limit generalization. (12)

PRP results do not establish the effectiveness of dextrose alone. Similarly, improvement after combined PRP and dextrose cannot reveal which component was responsible. Studies must be interpreted according to what was actually injected and where.

Why exercise and recovery remain relevant

Supporting ligaments and controlling muscles have complementary roles. Strength, endurance, and movement tolerance matter even when pain improves after an injection. A small lumbar series discussed stabilization exercises alongside injections, but did not isolate the contribution of either component. (10)

Exercise is an established part of many nonsurgical back-pain approaches, adjusted to the condition and the person’s tolerance. Extended inactivity can make return to normal activity harder. That does not mean pushing through new weakness or severe escalating pain. (13)

Published injection schedules range from single procedures to repeated sessions. These differences do not establish that everyone needs the same number of treatments. A response to an initial procedure, by itself, does not prove that continuing injections will produce further benefit.

Understanding the treatment photographs and anatomical illustrations

The original article’s anatomical illustration highlights the relationship between discs, facet joints, and supporting ligaments. It is useful for explaining how these structures share load, but should not be read as proof of the order in which degeneration occurs in every person.

The treatment photographs show ligament-attachment regions, including the sacroiliac area. Markings on the patient with scoliosis identify spinal position and the illustrated treatment area. They describe that example, not a universal injection map or a required extent of treatment.

Video: Low back pain and spinal instability

Our video, Low Back Pain Treated with Prolotherapy When Other Treatments Do Not Resolve Spinal Instability, discusses our clinical perspective on supporting tissues and persistent symptoms. It complements the research sections; clinical observations and proposed mechanisms should be distinguished from benefits established in controlled comparisons.

Limitations and safety: What the evidence does not establish

The new studies provide reasons to continue investigating dextrose, but several questions remain:

• Which diagnoses and patient characteristics predict benefit?
• Which injection targets and concentrations are most appropriate?
• How much benefit comes from the injection compared with accompanying care?
• How durable are improvements beyond the studied follow-up periods?
• Can structural repair be demonstrated independently of symptom improvement?

Pain scores, walking tolerance, sitting ability, and disability questionnaires measure meaningful outcomes. They do not directly measure ligament strength, disc regeneration, or prevention of future degeneration.

Risks vary with the procedure. Temporary soreness and bruising can occur; deeper spinal procedures have additional concerns, including infection, bleeding, and injury to nearby structures. Small trials and incomplete adverse-event reporting cannot establish the absence of uncommon complications. Comparisons of risks require attention to the specific injection rather than the label “Prolotherapy.”

What these findings mean for patients with persistent low back pain

We retain our interest in ligament support and lumbar stability while recognizing that the evidence is diagnosis-specific. The 2026 randomized trial provides a favorable comparison with epidural steroid injections for selected people with persistent back and leg pain. The systematic review offers a broader overview, but combines diverse conditions and procedures.

Earlier negative or mixed trials remain relevant. Our case examples show possible functional improvements, not outcomes that can be guaranteed. A meaningful discussion of treatment needs to account for the source of pain, neurological findings, prior surgery, the intervention studied, and its limitations.

For more focused information, see our articles on sacroiliac instability and SI joint pain and alternatives to epidural steroid injections.

Medical disclaimer: This article provides general educational information and does not diagnose the cause of back pain or recommend a particular procedure. Benefits, risks, and suitability depend on the underlying condition.

References

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