Ultrasound-Guided Surgery for Carpal Tunnel Syndrome: A New Interventional Procedure

Abstract

Carpal tunnel syndrome (CTS) may be treated surgically if medical treatment fails. The classical approach involves release of the flexor retinaculum by endoscopic or open surgery. Meta-analyses have shown that the risk of nerve injury may be higher with endoscopic treatment. The recent contribution of ultrasound to the diagnosis and therapeutic management of CTS opens new perspectives. Ultrasound-guided carpal tunnel release via a minimally invasive approach enables the whole operation to be performed as a percutaneous radiological procedure. The advantages are a smaller incision compared with classical techniques; great safety during the procedure by visualization of anatomic structures, particularly variations in the median nerve; and realization of the procedure under local anesthesia. These advantages lead to a reduction in postsurgical sequelae and more rapid resumption of daily activities and work. Dressings are removed by the third day postsurgery. Recent studies seem to confirm the medical, economic, and aesthetic benefits of this new approach.

Keywords: carpal tunnel release; carpal tunnel syndrome; interventional radiology; minimally invasive surgery; ultrasound-guided surgery; ultrasound-guided treatment.

Fig. 1

( a ) Instruments used for transection of the flexor retinaculum with ultrasound guidance and ( b ) patient position. The patient is lying down in the supine position, without a tourniquet, under strict aseptic conditions, with an open palm.

Fig. 2

Hydrodissection. ( a ) Subcutaneous anesthesia is introduced and the needle ( arrow ) is then advanced slowly through the middle of the safe zone between the median nerve (MN) and ulnar artery (UA), with continuous axial ultrasound monitoring. ( b ) Using injected anesthetic, hydrodissection prepares the carpal tunnel for the action of the hook knife.

Fig. 3

( a ) The hook knife is positioned horizontally. Corresponding axial ultrasound images at ( b ) the proximal and ( c ) distal carpal tunnel. Hook knife artifact ( arrow ) under the flexor retinaculum. Hook of Hamate bone (white star). Median nerve (MN) before and after division.

Fig. 4

( a ) The hook is turned vertically and the retinaculum is then transected in a retrograde manner with continuous ultrasound monitoring. Corresponding sagittal ultrasound image ( b , white arrow ) during progressive retrograde transection of the flexor retinaculum. Flexor retinaculum ( double arrow ).

Fig. 5

Percutaneous ultrasound-guided carpal tunnel release. Three-day postoperative appearance (right hand) and 6-week postoperative scar on the contralateral hand (left hand).