From Misdiagnosis to Relief: An Innovative Ultrasound-Guided Hydrodissection for Sural Nerve Entrapment Mimicking Achilles Tendinopathy in a Psoriasis Patient, Aided by Sonoguide Digital Palpation-Unveiling the Role of Fascia in Nerve Entrapment

Background: Psoriasis, a chronic immune-mediated inflammatory disease, can affect musculoskeletal components, including the Achilles tendon. Achilles tendon pain in psoriasis patients may stem from tendinitis or neuropathic pain due to peripheral nerve entrapment, such as sural nerve (SN) entrapment. Fascial tissues can play a critical role in nerve entrapment syndromes, contributing to nerve compression and pain. This case report explores SDP and ultrasound (US)-guided hydrodissection (HD) for SN entrapment mimicking Achilles tendinopathy in a psoriasis patient. Materials and Methods: A 41-year-old male with psoriasis presented with right heel stiffness and paresthesia. Physical examination, radiographs, and ultrasound were per-formed. Sonoguide Digital Palpation (SDP) was used to diagnose SN entrapment. US-guided HD was performed using 50 cc of 5% dextrose in water (D5W) below the psoriatic lesion. Results: SDP reproduced the patient's Achilles tendon pain, suggesting SN entrapment. Post-HD, the patient reported significant pain relief (NPRS score reduction from 8 to 2) and improved SN mobility. At 18-month follow-up, sustained symptom relief and complete functional recovery were reported. Discussion: US-guided HD, guided by SDP, may effectively manage neuropathic Achilles pain associated with SN entrapment in psoriasis patients. The positive outcome may be attributed to the mechanical separation of the nerve from surrounding tissues, potentially relieving pressure on the nervi nervorum and vasa nervorum, along with the potential biochemical effects of HD and the accuracy of SDP diagnosis. The hydrodis-section targets the fascia surrounding the nerve, releasing it from compressive forces. Conclusion: US-guided HD of the SN shows promise for managing neuropathic Achilles pain in psoriasis patients with SN entrapment. This case highlights the potential role of fascial pathology in nerve entrapment syndromes. At 18-month follow-up, the patient maintained complete functional recovery with a sustained 75% reduction in NPRS score. Further research with larger, controlled studies, objective outcome measures, and long-term follow-up is needed to confirm efficacy and elucidate underlying mechanisms. Future studies should also investigate fascial characteristics using advanced ultrasound techniques.