Novel Motor-Sparing Ultrasound-Guided Neural Injection in Severe Carpal Tunnel Syndrome: A Comparison of Four Injectates

Abstract

Nerve hydrodissection uses fluid injection under pressure to selectively separate nerves from areas of suspected entrapment; this procedure is increasingly viewed as potentially useful in treating carpal tunnel syndrome (CTS). The usage of normal saline (NS), 5% dextrose water (D5W), platelet-rich plasma (PRP), and hyaluronic acid (HA) as primary injectates for hydrodissection without an anesthetic can limit anesthetic-related toxicity and preserve the motor functions of the median nerve. Here, we describe a novel motor-sparing neural injection and compare the effect of these four injectates for severe CTS. We retrospectively reviewed the outcomes of 61 severe CTS cases after a single neural injection with NS, D5W, PRP, or HA. Outcomes were evaluated on the 1^st and 6^th months postinjection, including the Boston Carpal Tunnel Questionnaire (BCTQ) scores and the nerve cross-sectional area (CSA). The results revealed that PRP, D5W, and HA were more efficient than NS at all measured time points (p < 0.05), except for CSA at the 1^st month between the NS and D5W groups. Single-injections of PRP and D5W seemed more effective than that of HA within 6 months postinjection for symptom and functional improvement (6^th-month BCTQ-symptom, D5W vs. HA, p = 0.047; 1^st-month BCTQ-symptom, PRP vs. HA, p = 0.018; 1^st- and 6^th-month BCTQ-function, D5W vs. HA, p = 0.002 and 0.016, respectively; 1^st-month BCTQ-function, PRP vs. HA, p < 0.001). For reducing CSA, PRP and HA seemed more effective than D5W (HA > PRP > D5W on the 1^st month and HA vs. D5W, p = 0.001; PRP > HA > D5W on the 6^th month and PRP vs. D5W, p = 0.012).