This is a prospective randomized single-blind clinical trial comparing in-plane ulnar approach carpal tunnel injection versus out-plane carpal tunnel injection and blind injection of 40 mg of triamcinolone in patients with idiopathic CTS in terms of efficacy and safety. The patients were maintained in the supine position, with the forearm supinated and the wrist placed in slight dorsiflexion position to prevent change in the appearance of the median nerve according to wrist position (Figure 1 ).
In blind injection, after skin antisepsis, the 26-gauge needle was inserted into the proximal carpal tunnel at the distal wrist crease just ulnar to the palmaris longus tendon. The out-plane approach was performed using a perpendicularly placed transducer, and the needle was inserted into the proximal carpal tunnel at the distal wrist crease just ulnar to the palmaris longus tendon.4 The needle tip was identified as a moving reflector in real time as the tip passed obliquely from the skin surface to the proximal to distal carpal tunnel. In the in-plane ulnar approach, the transducer is moved ulnarly while keeping the median nerve in view (Figure2 A). In this manner, the pisiform, ulnar nerve, and ulnar artery are brought into view (Figure 2 B).4 The pisiform appears as a prominent superiorly rounded hyperechoic structure on the ulnar side of the screen. The ulnar nerve lies just radial to the pisiform, and the ulnar artery lies radial to the ulnar nerve. Doppler images can confirm the position of the ulnar artery.7 (link) Although the optimal injectable location has not been determined, target sign which is produced by injectate as a ring form structure is used as a proper injection guideline.
A typical injectate consists of 1 mL of 40 mg/mL triamcinolone and 1 mL of 1% lidocaine, delivered in equal portions above the nerve, below the nerve, and into the subsynovial connective tissue. After completion of the injection, the distal carpal tunnel is scanned to ensure distribution of injectate throughout the proximal-to-distal extent of the carpal tunnel.7 (link) All injections were performed by the same physician. The US-guided injections were performed using an US device (GE healthcare, Hertfordshire, UK).
In blind injection, after skin antisepsis, the 26-gauge needle was inserted into the proximal carpal tunnel at the distal wrist crease just ulnar to the palmaris longus tendon. The out-plane approach was performed using a perpendicularly placed transducer, and the needle was inserted into the proximal carpal tunnel at the distal wrist crease just ulnar to the palmaris longus tendon.4 The needle tip was identified as a moving reflector in real time as the tip passed obliquely from the skin surface to the proximal to distal carpal tunnel. In the in-plane ulnar approach, the transducer is moved ulnarly while keeping the median nerve in view (Figure
A typical injectate consists of 1 mL of 40 mg/mL triamcinolone and 1 mL of 1% lidocaine, delivered in equal portions above the nerve, below the nerve, and into the subsynovial connective tissue. After completion of the injection, the distal carpal tunnel is scanned to ensure distribution of injectate throughout the proximal-to-distal extent of the carpal tunnel.7 (link) All injections were performed by the same physician. The US-guided injections were performed using an US device (GE healthcare, Hertfordshire, UK).
