TITLE:
Trapezius Muscle and Spinal Accessory Nerve Hydrodissection: A Case Report
AUTHORS:
Oisín Pennycook, Amy Ahern, Dominic C. Harmon
KEYWORDS:
Hydro Dissection, Myofascial, Neck Pain, Trapezius: Spinal Accessory Nerve, Ultrasound
JOURNAL NAME:
Pain Studies and Treatment,
Vol.14 No.4,
September
24,
2026
ABSTRACT: Background: Neck pain is common. Joint and muscle source of neck pain is common. Hydro dissection is a minimally invasive technique involving injection of fluid to separate fascial layers and release entrapped nerves and tendons. Its use in trapezius hydro dissection has been reported. The spinal accessory nerve innervates the trapezius muscle. Simultaneous hydro dissection of the trapezius muscle and spinal accessory nerve has not been reported. The simultaneous technique may offer benefit in this patient cohort. Methods: Case Presentation: A 42-year-old female presented with chronic unilateral neck and shoulder pain, which was minimally responsive to first-line treatment. She had undergone physiotherapy and was on regular oral analgesics. Intervention: In a theatre setting, under monitoring and sterile conditions, the patient underwent an ultrasound-guided procedure. 15 ml of 5% Dextrose was injected to release pressure on the nerves and surrounding tissue, by spreading apart layers of fascia of the trapezius muscle and the spinal accessory nerve. Results: The patient reported immediate relief from symptoms on palpation and lateral neck stretch. She was followed up at eight weeks and disclosed no complications; in fact, she obtained a significant improvement in pain scores (6/10 to 2/10 NRS), quality of life and was able to complete activities of daily living with increased ease. No regular analgesics were required at follow-up. Conclusions: We report this case as an example of how a simultaneous hydro-dissection of the trapezius and spinal accessory nerve may be used as a minimally invasive therapeutic intervention for long-term relief of refractory, debilitating trapezius related myofascial neck pain.