Intraoperative perineural hyaluronic acid injection does not improve outcomes after carpal tunnel release in moderate-to-severe CTS: a retrospective cohort study

Abstract

Aims: This study aims to evaluate whether intraoperative perineural hyaluronic acid (HA) injection provides additional clinical or electrophysiological benefits beyond standard carpal tunnel release (CTR) in patients with moderate-to-severe carpal tunnel syndrome (CTS). Methods: In this retrospective cohort study, 130 patients with electrophysiologically confirmed moderate-to-severe CTS underwent either CTR alone (n=66) or CTR with intraoperative perineural HA injection (n=64). HA (Alsegovisc®, 40 mg/2 ml, 1500 kDa) was administered following surgical decompression. Outcomes included pain (Visual Analog Scale, VAS), symptom severity and function (Boston Carpal Tunnel Questionnaire, BCTQ), sensory and motor conduction (SNCV, DML), and achievement of patient-centered benchmarks (minimal clinically important difference, MCID; patient acceptable symptom state, PASS). Evaluations were carried out pre-surgically and at 3- and 6-month intervals following the procedures. Results: Both groups demonstrated significant improvements in pain (VAS: 7.0 to 2.0), symptom severity (BCTQ-SSS: 45.0 to 18.0), function (BCTQ-FSS: 34.5 to 13.5), and electrophysiological parameters (SNCV: 31.4 to 40.5 m/s; DML: 5.5 to 4.2 ms) over 6 months (all p<0.001). However, The comparison did not yield statistically significant results between groups at any time point (p>0.05), and effect sizes were consistently small (Cohen’s d<0.2). MCID and PASS thresholds were met by >68% of patients in both groups. Subgroup analyses revealed no predictive value for baseline disease severity or thenar atrophy. Conclusion: Intraoperative perineural HA injection did not confer additional clinical or electrophysiological benefit over CTR alone in moderate-to-severe CTS. Despite compelling preclinical data, HA's efficacy may be attenuated in chronic fibrotic nerve compression due to pharmacokinetic and tissue-level limitations. These findings do not support routine use of intraoperative HA in advanced CTS but highlight the need for future prospective trials targeting earlier-stage disease, sustained-release formulations, or repeated dosing strategies.

Keywords

• Carpal tunnel syndrome
• hyaluronic acid
• perineural injection
• carpal tunnel release
• moderate to severe neuropathy

Intraoperative perineural hyaluronic acid injection does not improve outcomes after carpal tunnel release in moderate-to-severe CTS: a retrospective cohort study

Abstract

Aims: This study aims to evaluate whether intraoperative perineural hyaluronic acid (HA) injection provides additional clinical or electrophysiological benefits beyond standard carpal tunnel release (CTR) in patients with moderate-to-severe carpal tunnel syndrome (CTS). Methods: In this retrospective cohort study, 130 patients with electrophysiologically confirmed moderate-to-severe CTS underwent either CTR alone (n=66) or CTR with intraoperative perineural HA injection (n=64). HA (Alsegovisc®, 40 mg/2 ml, 1500 kDa) was administered following surgical decompression. Outcomes included pain (Visual Analog Scale, VAS), symptom severity and function (Boston Carpal Tunnel Questionnaire, BCTQ), sensory and motor conduction (SNCV, DML), and achievement of patient-centered benchmarks (minimal clinically important difference, MCID; patient acceptable symptom state, PASS). Evaluations were carried out pre-surgically and at 3- and 6-month intervals following the procedures. Results: Both groups demonstrated significant improvements in pain (VAS: 7.0 to 2.0), symptom severity (BCTQ-SSS: 45.0 to 18.0), function (BCTQ-FSS: 34.5 to 13.5), and electrophysiological parameters (SNCV: 31.4 to 40.5 m/s; DML: 5.5 to 4.2 ms) over 6 months (all p<0.001). However, The comparison did not yield statistically significant results between groups at any time point (p>0.05), and effect sizes were consistently small (Cohen’s d<0.2). MCID and PASS thresholds were met by >68% of patients in both groups. Subgroup analyses revealed no predictive value for baseline disease severity or thenar atrophy. Conclusion: Intraoperative perineural HA injection did not confer additional clinical or electrophysiological benefit over CTR alone in moderate-to-severe CTS. Despite compelling preclinical data, HA's efficacy may be attenuated in chronic fibrotic nerve compression due to pharmacokinetic and tissue-level limitations. These findings do not support routine use of intraoperative HA in advanced CTS but highlight the need for future prospective trials targeting earlier-stage disease, sustained-release formulations, or repeated dosing strategies.

Keywords

• Carpal tunnel syndrome
• hyaluronic acid
• perineural injection
• carpal tunnel release
• moderate to severe neuropathy

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