Palmaris longus interposition in revision surgery for recurrent and persistent carpal tunnel syndrome: a case series

Carpal tunnel syndrome (CTS) is the most frequently operated neurological disorder of the hand. Incidence of patients remaining symptomatic has been reported up to 30% after primary release. Revision surgery remains challenging although multiple surgical options have been described. In this case series a simple novel technique, the palmaris longus interposition, is described for the treatment of recurrent and persistent CTS. Patients who underwent PLI between October 2013 and 2018 and without underlying neurological or hand disorders severely affecting the operated hand were eligible for inclusion. All were preoperatively diagnosed with recurrent or persistent CTS based on clinical assessment. Eighteen patients with 20 operated hands consented to the study. Patient characteristics were retrospectively reviewed, including nerve conduction studies and ultrasound scans. Patients were postoperatively asked to classify their symptoms as resolved, improved, not improved or worsened. In addition, postoperative symptom severity and functional status were assessed using the Boston Carpal Tunnel Questionnaire. Ten hands showed recurrent symptoms while the other 10 showed persistent symptoms. The average follow-up was 15 months. No improvement was reported in 5 hands, whereas improvement or complete relief of symptoms was reported in 15 hands. The mean total score of the Boston Carpal Tunnel Questionnaire postoperatively was 2.29 and ranged between 1.26 and 4.32. These results suggest that using the palmaris longus tendon as interposition graft between the leaves of the flexor retinaculum may be a suitable technique for the management of patients with mild to moderate symptoms of recurrent and persistent CTS. Further research should investigate whether this technique has better outcome compared to other procedures.