e super, m smith, m miller, j smith, x yuan

Objectives: Carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy. Anatomic variations of the median nerve (MN) and carpal tunnel (CT) may predispose patients to CTS or increase procedural complexity and risk during carpal tunnel release (CTR). This study aimed to systematically evaluate the prevalence of 25 MN and CT anatomic variations and measurements using ultrasound (US) in patients referred for electrodiagnostic testing (EDX).

Methods: In this cross-sectional observational study, patients underwent diagnostic US exams of the MN (mid-brachium to distal CT), focused on variant anatomy that may predispose to CTS (bifid MN, Gantzer's muscle, lumbrical intrusion) or increase procedural complexity/risk (transligamentous thenar motor branches [TMBs], MN orientation ulnar to the palmaris longus [PL] tendon).

Results: Two hundred and twenty patients (mean age: 45.3 ± 13.0 years; 63.6% male; 294 UEs) were evaluated by US. Hundred and eight UEs met EDX criteria for CTS (EDX-CTS). The most common variations identified were lumbrical intrusion (81.3%), Gantzer's muscle (39.5%), and persistent median artery (22.8%), which were not associated with EDX-CTS. US revealed transligamentous (2.4%) and ulnar origin (4.5%) TMBs, which may increase injury risk during CTR. MN location was ulnar to the PL tendon in 70.4% of wrists, which can predispose to injury during landmark-guided CT injections.

Conclusions: This study demonstrated that US complements EDX and can systematically identify anatomic variations, including variants at risk during CTS interventions. No differences in the prevalence of variations were detected between patients with and without EDX-CTS. Diagnostic US can support procedural planning, improve safety, and lower injury risk.

Super EJ, Smith MS, Miller ME, Smith J, Yuan X. Ultrasonographic Assessment of Median Nerve and Carpal Tunnel Variations: Implications for the Interventional Management of Carpal Tunnel Syndrome. J Ultrasound Med. 2025 Jun 18. doi: 10.1002/jum.16733. Epub ahead of print. PMID: 40530498.

Persinger J and Hager N

The Physical Medicine and Rehabilitation Clinic (PM&R) at Walter Reed National Military Medical Center (WRNMMC) augmented their high frequency ultra-sound systems with an ultra-high frequency ultrasound(UHFUS) system for use in the diagnosing and treatment of musculoskeletal (MSK) and nerve injury warfighters. The Visualsonics VevoMD is an UHFUS system with operating frequencies in the 24–70 MHz range as compared to the typical POC and tertiary care ultrasound systems operating in the15–22 MHz range. Access to this system afforded a unique opportunity to explore the usefulness of this cutting-edge technology in the unique settings of limb loss and multi-trauma in the military.

Persinger, J. E., & Hager, N. (2022). Unique Diagnostic Capabilities and Impact of Ultra-High Frequency Ultrasound in the Musculoskeletal Clinical Setting. Journal of Ultrasound in Medicine. https://doi.org/https://onlinelibrary.wiley.com/doi/epdf/10.1002/jum.16028