Ultrasound-guided nerve Hydrodissection (HD) is a minimally invasive technique involving fluid injection to separate tissue planes, particularly around peripheral nerves. In pain medicine, HD is increasingly used to treat neuropathic pain syndromes by mechanically separating entrapped nerves from surrounding tissues, thereby restoring nerve mobility and improving injectate dispersion. Cadaveric work by Evers et al. demonstrated that Hydrodissection can reduce peak gliding resistance of the median nerve within the carpal tunnel by approximately 21%, lending biomechanical support to the decompression rationale for this procedure [1]. Clinical evidence has steadily expanded: multiple randomized controlled trials, including those by Wu et al., have shown that perineural injection of 5% dextrose outperforms both saline and corticosteroid for carpal tunnel syndrome in terms of pain relief and functional improvement [2][3]. Similar benefits have been observed in ulnar neuropathy at the elbow, Chen, and meralgia paresthetica, Shi, indicating the technique’s versatility across entrapment syndromes [4][5].

Beyond symptomatic improvement, HD may play a role in neural regenerative strategies. Trescot and Brown outlined its potential in combination with regenerative injectates such as platelet lysate or stem cell derivatives, aiming not only to decompress but also to enhance neural recovery [6]. Furthermore, optimization of technique—including injectate type and volume—has been explored in trials like Eyvaz, which found that 10 mL of 5% dextrose provided superior outcomes to smaller volumes [7]. The physiological basis for Hydrodissection includes decompression of the nervi nervorum and vasa nervorum, structures critical for neural feedback and vascular supply. Entrapment of these may contribute to ischemia, stasis, and ongoing nociceptive input, potentially resulting in chronic pain. Although interest is growing, the clinical literature remains fragmented, with variations in technique, injectates, and outcome reporting. This review synthesizes current evidence on the efficacy and safety of Ultrasound-guided Hydrodissection.

To evaluate the effectiveness of ultrasound-guided nerve Hydrodissection in the management of pain conditions.To assess safety outcomes and complication rates.To summarize current procedural techniques and emerging recommendations for ultrasound-guided hydrodissection.

A structured literature search was performed using PubMed, Embase, Cochrane Library, and Google Scholar. Keywords included “ultrasound-guided hydrodissection”, “nerve entrapment”, “cervical facet joint disease”, and “neck pain”. The search focused on studies published in the last 15 years and used Boolean operators to refine results. Eligible studies involved adult populations receiving US-HD for neuropathic or nociceptive pain, with outcomes including pain reduction, functional improvement, safety, and long-term follow-up. Eligible studies included adult patients undergoing ultrasound-guided nerve hydrodissection for peripheral or spinal nerve entrapments, including but not limited to carpal tunnel syndrome, ulnar neuropathy, meralgia paresthetica, and cervical radicular pain.

Database queries included full Boolean strings (PubMed: “ultrasound-guided hydrodissection” AND “nerve entrapment” etc.). Searches performed up to March 2024, English-language only.

Inclusion criteria:

Adult patients with neuropathic or nociceptive pain due to peripheral or spinal nerve entrapment (e.g., carpal tunnel syndrome, ulnar neuropathy, meralgia paresthetica, cervical radicular pain).Intervention: ultrasound-guided hydrodissection using any injectate (e.g., saline, dextrose, steroid).Reported outcomes: pain relief, function, complications, or follow-up.Study designs: RCTs, prospective cohorts, case series.

Exclusion criteria:

Non-ultrasound-guided interventions.Non-Hydrodissection techniques.Paediatric or animal studies.Editorials, narrative reviews, or duplicate publications.

After applying eligibility criteria, 17 studies were selected for in-depth analysis. A PRISMA flow diagram is provided to illustrate the selection process( see Figure 1).

This review highlights ultrasound-guided nerve hydrodissection as a clinically effective, safe, and scalable intervention for a range of nerve entrapment syndromes. For Carpal Tunnel Syndrome (CTS), US-HD provides outcomes similar to surgery but with lower associated morbidity [8][22]. Evidence for cervical radicular pain, remains limited [11]. Safety data are consistent across studies, with very low rates of serious complications [12][15][16]. The success of the technique appears to depend on operator skill, image quality, and injectate choice [14]. However, inconsistencies in methods, injectates, and outcome reporting limit the ability to generalize findings [19][21]. Clinical standardization, along with rigorous randomized trials and long-term outcome tracking, is urgently needed to establish US-HD as a first-line intervention [16]. Research has proposed that dextrose may modulate TRPV1 receptor activity, potentially reducing nociceptive signaling in neuropathic pain. In addition, the chronic constriction injury model supports the concept of mechanical decompression to relieve fascicular swelling. These physiological insights enhance our understanding of HD’s multifactorial benefits. Overall, this review cites 24 references, of which 17 are primary included studies.

This review has several limitations. The included studies demonstrate substantial variability in injectates, volumes, and procedural techniques, limiting direct comparison. Many studies had small sample sizes and heterogeneous outcome measures. A formal meta-analysis was not possible due to methodological differences. Only English-language studies were included, introducing potential language bias. Additionally, publication bias cannot be excluded, as studies with negative results may be underrepresented. These limitations should be considered when interpreting the findings.

Ultrasound-guided nerve Hydrodissection (US-HD) is a minimally invasive and safe procedure that has shown effectiveness in treating nerve entrapment-related pain. It consistently yields positive results in conditions such as carpal tunnel syndrome and cervical radiculopathy, with a low risk of complications. As imaging technology and procedural methods continue to advance, US-HD is emerging as a promising non-surgical option, particularly in outpatient settings. Ongoing research should aim to optimize injectate formulations, enhance ultrasound techniques, and conduct large-scale comparative studies to better define its role in pain management.

Future research should aim to standardize the type of fluid used, injection volume, and frequency. Direct comparisons through head-to-head randomized trials between Hydrodissection and other interventional techniques are needed. Additionally, long-term follow-up—including recurrence rates and cost-effectiveness analyses—will be essential to assess the durability and sustainability of clinical outcomes.

The authors received no financial support for this work.

Table S1 summarizes the characteristics of the included studies.

The table below provides a comparative overview of the seventeen key studies included in this review. It summarizes their design, strengths, limitations, and key contributions to the field of ultrasound-guided nerve Hydrodissection.

Table S1. Summary of Ultrasound-Guided Hydrodissection studies.

Several studies expanded the application of US-HD beyond carpal tunnel syndrome to include ulnar nerve entrapment, piriformis syndrome, and sciatic neuropathy. Malone et al. described a technique involving fluid dissection beneath the flexor retinaculum for the median nerve, with variable long-term outcomes over a 24-month follow-up. Imaging guidance has improved procedural safety and accuracy, although inadvertent nerve injection remains a concern [15]. Observed a 17% rate of unintentional intraneural injection using ultrasound during shoulder blocks; however, no lasting neurological complications were reported. Brull’s systematic review estimated neuropathy rates under 3 in 100 cases, reinforcing the favourable safety profile of peripheral nerve blocks, including HD [16].