Nerve Hydrodissection & Perineural Injection Brisbane

"Nerve therapy" covers a few different injection approaches for nerve-related pain. The main ones are perineural injection therapy (sometimes called superficial prolotherapy) and ultrasound-guided nerve hydrodissection. They share a family resemblance but work differently and have different levels of evidence, so we are specific about which one is being considered and why.

What it can help with

Carpal tunnel syndrome (mild-to-moderate) — the best-supported use
Localised nerve-related pain, burning or hypersensitive skin areas
Pain from a superficial nerve irritated by scar or overuse
Selected nerve entrapments where tethering or adhesion is suspected

Suitability depends on your individual diagnosis and is assessed at consultation.

Nerve-related pain can come from a nerve that is irritated, sensitised or physically tethered by surrounding tissue. Several injection approaches are used to address this, and they are often grouped together as “nerve therapy” even though they are not the same procedure.

Perineural injection therapy — also described as superficial prolotherapy — involves small injections of a dilute dextrose solution placed just beneath the skin over tender superficial nerves. Ultrasound-guided hydrodissection is a different, image-guided procedure in which fluid is used to separate a nerve from the tissue compressing or tethering it. The two are sometimes used together conceptually, but they differ in depth, technique and the strength of evidence behind them.

Rather than present these as a single interchangeable treatment, we assess which approach — if either — is appropriate for your specific problem, and we are transparent about how strong the evidence is for that use. The clearest evidence is for ultrasound-guided hydrodissection in mild-to-moderate carpal tunnel syndrome; other uses are more provisional. Whether a nerve problem is better managed with injection, rehabilitation, or a surgical opinion is part of that discussion.

How it works

These treatments are grouped by what they target and how they are thought to work.

Perineural injection therapy / superficial prolotherapy. A series of small injections of low-concentration (usually 5%) dextrose is placed just under the skin over tender superficial nerves. The proposed mechanism is modulation of irritated small sensory (C-fibre) nerves and neurogenic inflammation. Proposed mediators include TRPV1 signalling, substance P and acid-sensing ion channels (ASIC1a) — supported by laboratory work — but this remains a hypothesised mechanism in humans rather than an established one.

Ultrasound-guided hydrodissection. Using real-time ultrasound, fluid is injected around a nerve to mechanically separate it from surrounding fascia or constricting tissue, release adhesions and improve how the nerve glides. This decompression effect is mechanically intuitive, and there appears to be a volume-dependent component — larger fluid volumes have outperformed smaller ones in trials even with the same injectate. When dextrose is used, a second, biochemical analgesic effect (via the pathways above) may add to the mechanical one.

What the evidence shows

The two approaches sit at different evidence levels, and it is important not to borrow the stronger data from one to justify the other. Hydrodissection has the clearest evidence, specifically in carpal tunnel syndrome. Randomised controlled trials and systematic reviews support improvements in symptoms, function, nerve-conduction measures and ultrasound appearance in mild-to-moderate carpal tunnel syndrome. A placebo-controlled trial of ultrasound-guided 5% dextrose reported benefit lasting to six months, and a later trial found larger fluid volumes more effective — pointing to a real mechanical effect. Not every study is positive: adding hydrodissection to a corticosteroid injection did not beat corticosteroid alone in one trial, which is a useful check against over-claiming. Overall certainty is low-to-moderate for carpal tunnel syndrome, and lower or insufficient for other nerve entrapments. Classic superficial perineural injection therapy has weaker evidence. The original superficial technique is supported mainly by case series and training materials rather than rigorous randomised trials, so its evidence quality is low to very low. Much of the better modern data actually concerns ultrasound-guided perineural dextrose around entrapment nerves — closer to hydrodissection than to the original blind superficial method. The safety profile of low-concentration dextrose appears favourable, but that is not the same as proof of broad effectiveness. In short: hydrodissection for carpal tunnel syndrome is a reasonable, evidence-supported non-surgical option; the superficial technique is more provisional, and we will be clear about which applies to you.

Sources: Dextrose injection — prolotherapy, perineural injection therapy & hydrodissection (AAPM&R PM&R KnowledgeNow) , Ultrasound-guided perineural hydrodissection for carpal tunnel syndrome — systematic review (J Pers Med, 2024) , Six-month efficacy of perineural 5% dextrose for carpal tunnel syndrome — placebo-controlled RCT (2017) , Volume-dependent effect of perineural dextrose in carpal tunnel syndrome — RCT (2020)

What to expect

Both approaches are done in the clinic without a general anaesthetic. Hydrodissection is performed under ultrasound guidance so the needle and fluid can be directed accurately around the nerve. Perineural injection therapy is usually a series of small injections over several sessions. The number of sessions, the injectate and whether either approach suits you depend on your diagnosis and are discussed at consultation, along with the current evidence and cost. Where a nerve is significantly compressed or there is major weakness, a surgical opinion may be more appropriate, and we will say so.

Frequently asked questions

What is the difference between perineural injection therapy and hydrodissection?

Perineural injection therapy (superficial prolotherapy) uses small injections of dilute dextrose just under the skin over tender nerves, aiming to settle irritated sensory nerves. Hydrodissection is an ultrasound-guided injection that places fluid around a deeper nerve to physically free it from surrounding tissue. They overlap in idea but differ in depth, technique and evidence.

Which nerve conditions have the best evidence?

Carpal tunnel syndrome — particularly mild-to-moderate cases — has the strongest evidence, mainly for ultrasound-guided hydrodissection with dextrose. Evidence for other nerve entrapments is thinner, and the classic superficial injection technique is supported mostly by lower-quality studies.

Is it a cure, or does it replace surgery?

Neither is a guaranteed cure or a universal substitute for surgery. They are non-surgical options worth considering in selected cases, especially milder carpal tunnel syndrome or where someone wants to avoid or delay surgery. Significant nerve compression or weakness may still need a surgical opinion.

Is it safe?

In experienced hands the reported complication rate is low, and dextrose is a low-concentration, well-tolerated injectate. Usual injection precautions apply — local infection, bleeding risk and being able to see the nerve safely on ultrasound. We assess suitability individually.

How strong is the evidence, honestly?

Low-to-moderate certainty for hydrodissection in carpal tunnel syndrome, and low or insufficient elsewhere. The superficial injection technique is lower still. We think that is worth being upfront about, and we will match the treatment to what the evidence actually supports for your problem.

Ready for a clearer plan for your back or musculoskeletal pain?

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Your assessment focuses on understanding the likely source of your pain and the most appropriate non-surgical options for your diagnosis, with the aim of reducing pain and improving function.

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Nerve Therapy & Hydrodissection