Wrist pain is prevalent, often resulting from repetitive movements and overuse associated with sports, work-related tasks, and the frequent use of personal handheld devices such as mobile phones and desktop keyboards [1] . Classified as a type of musculoskeletal pain, wrist pain is widespread in the UK, with an annual consultation prevalence rate of 58 per 10,000 patients in primary care [2] . This makes the wrist the fourth most common site of musculoskeletal pain in the upper limb, following the shoulder, hand, and elbow respectively [2] .

Intersection Syndrome (IS), a form of inflammatory tenosynovitis, occurs at the intersection of the first and second dorsal compartments of the wrist. The first dorsal compartment is comprised of the tendons of the abductor pollicis longus and extensor pollicis brevis, while the second dorsal compartment contains the tendons of the extensor carpi radialis longus and extensor carpi radialis brevis.

Intersection syndrome is an overuse injury frequently encountered by sportspeople that necessitates a thorough clinical assessment for accurate diagnosis. In some cases, magnetic resonance imaging may be required to rule out other tissue abnormalities, alongside ultrasound and patient-reported symptoms [3] . Clinically, IS is diagnosed based on pain located in the dorsoradial forearm, approximately five cm from the wrist joint, which is exacerbated by resisted wrist and thumb extension.

Accurate diagnosis is crucial to ensure that the appropriate treatment is provided, leading to the best possible outcome for the patient. In cases of wrist pain, it is essential to rule out other similar presentations. Differential diagnoses to consider include: De Quervain’s tenosynovitis (which primarily affects the first extensor compartment and is more localized at the radial styloid), osteoarthritis of the carpometacarpal joint, entrapment of the dorsal radial sensory nerve (Wartenberg’s syndrome) and extensor pollicis longus tendinitis. Simple strains, sprains, and fractures must also be considered [4] [5] .

Conservative treatment for IS typically includes rest, the use of a splint or hand support, analgesics such as non-steroidal anti-inflammatory drugs (NSAIDs), and physiotherapy focused on strength and conditioning. If these measures fail to promote healing and alleviate symptoms, corticosteroid injections may be administered to reduce inflammation. If the condition persists despite these interventions, surgical options may be considered [3] .

Hydrodissection involves injecting a local anaesthetic, saline, or a 5% dextrose solution with the goal of separating nerves or other anatomical structures from adjacent tissues, fascia, or surrounding structures [6] . The therapeutic benefits of hydrodissection are thought to arise from the alleviation of compression on the nervi nervorum or vasa nervorum [6] . Accurate identification of these structures and precise injection into the correct anatomical sites are best achieved using ultrasound guidance.

The aim of this study was to assess the role of hydrodissection in the treatment of intersection syndrome using ultrasound guidance.

A 32-year-old male presented with severe, chronic pain in his right wrist. The patient, who was an active hurling player, experienced exacerbation of pain during certain manoeuvres in the sport. Clinical diagnosis was confirmed based on pain localized to the dorsoradial forearm, approximately five cm from the wrist joint, which worsened with resisted wrist and thumb extension. The pain significantly affected his work, athletic performance, and daily activities. Conservative management, consisting of physiotherapy and splinting support, failed to control his symptoms.

Dynamic ultrasound scanning of the affected area was conducted to examine the anatomical structures, identify any hypoechoic areas indicating localized pathology, and compare them with the left wrist. The skin was prepared with Chlorprep, and ultrasound guidance was used throughout the procedure to ensure continuous visualization. Aseptic technique was strictly maintained as the needle was carefully positioned at the targeted sites. After confirming the accurate placement of the needle tip, 5 mL of 0.25% chirocaine was injected, which had an immediate analgesic effect. Subsequently, 10 mL of 5% dextrose was administered for hydrodissection, with clear visualization of the distribution of the solution ( Figure 1 ). No adverse effects or complications were noted during or after the procedure.

The patient reported a sustained analgesic effect at three months, with continued improvement and a return to sports activities. Further follow-up is scheduled.

This is the first documented case of using ultrasound-guided hydrodissection for the therapeutic management of intersection syndrome (IS). This novel approach provides a promising non-operative option for treating this overuse injury, potentially reducing the need for surgical intervention and decreasing rehabilitation time. The case highlights that combining hydrodissection with a structured physiotherapy rehabilitation program can yield optimal patient outcomes. Additionally, this method may decrease reliance on oral analgesics and other repetitive non-operative treatments, such as steroid injections.

Ultrasound is a valuable tool for assessing tissue health in the upper limb, especially when comparing it to the unaffected limb. It offers several advantages: it is efficient, non-invasive, and does not involve radiation. Moreover, patient mobility does not affect image quality or accessibility, making it a reliable option. Ultrasound can decrease the reliance on other imaging modalities, such as MRI, which can be stressful and anxiety-inducing for patients, and may elucidate artifacts that compromise image quality [7] . Additionally, ultrasound minimizes the need for CT and X-ray imaging, thereby limiting radiation exposure.

In the context of IS, ultrasound serves a dual purpose: it provides dynamic real-time imaging and facilitates therapeutic intervention. Consequently, a patient with IS can be scanned, diagnosed, and treated in a single visit, making this approach both time-efficient and cost-effective.

The aim of this study was to evaluate the effectiveness of hydrodissection in treating intersection syndrome. In this case, we observed a significant improvement in the patient’s symptoms following hydrodissection. This minimally invasive intervention, may present a viable alternative to surgical options, particularly for patients who do not achieve optimal results with traditional conservative treatments. Further research is needed to assess its efficacy. As a novel and promising method in pain medicine, hydro dissection represents an exciting area for future therapeutic investigation.

This case report is an honest, accurate, and transparent account of the case being reported. No important aspects of the report have been omitted. Any queries should be directed to the corresponding author via email. Requests for reprints should also be addressed to the corresponding author.

This study is fully compliant with the ethical guidelines of the Research Ethics and Clinical Trials Committee of the University of Limerick Hospitals Group.

The patient consented to participation and publication of the report as described.

We would like to extend our gratitude to the patient for his consent to publish this report.