Feasibility of a medial tenoscopic portal in the equine carpal flexor tendon sheath in cadavers.
Authors: Woods Thomas, Dixon Jonathon, Melvaine Chris, Fraser Barny
Journal: Veterinary surgery : VS
Summary
Endoscopic visualisation of the carpal flexor tendon sheath presents significant technical challenges, particularly when accessing pathology on the medial aspect of the space, and current lateral approaches limit surgeon triangulation and instrument manoeuvrability. Woods and colleagues used contrast-enhanced CT imaging combined with cadaveric dissection to map a safe medial portal entry point, positioning a needle 5 mm proximal and 32 mm caudal to the distal medial radial physis on 20adult Standardbred forelimbs. The proposed medial location avoided macroscopic damage to intrathecal structures and the cephalic vein in 95% of cases, though impingement of the flexor carpi radialis tendon occurred in 35% of specimens—a consideration requiring technique refinement or careful instrument selection. Establishing this medial portal anatomy may substantially improve surgical access and instrument triangulation for addressing flexor sheath pathology, potentially reducing operative time and tissue trauma compared with relying solely on lateral approaches. Clinicians should recognise that individual anatomical variation exists and that the 35% incidence of FCRT impingement warrants further investigation into whether dynamic imaging or alternative portal positioning might reduce this contact rate before routine clinical adoption.
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Practical Takeaways
- •A new medial portal location (5 mm proximal, 32 mm caudal to distal medial radial physis) has been anatomically validated in cadavers and may improve your ability to visualize and treat lesions in the carpal flexor sheath
- •Be aware that this portal location risks impingement of the flexor carpi radialis tendon (35%) and cephalic vein (5%), so careful needle placement and awareness of surrounding structures is essential during clinical application
- •This cadaver study provides the anatomical foundation for clinical trials; safe clinical implementation will require validation in live horses and training in proper technique before routine adoption
Key Findings
- •A medial tenoscopic portal located 5 mm proximal and 32 mm caudal to the distal medial radial physis was successfully placed without causing macroscopic intrathecal or superficial damage in cadavers
- •Impingement of the flexor carpi radialis tendon occurred in 35% of specimens and cephalic vein impingement in 5% of specimens with the proposed portal location
- •The medial portal approach provides feasibility for improved triangulation and visualization during carpal sheath endoscopy