Major complications after 400 continuous popliteal sciatic nerve blocks for post-operative analgesia

A continuous popliteal sciatic nerve block (CPSNB) has been performed with increasing frequency for post-operative analgesia after foot surgery. Major complications associated with the placement of a perineural catheter remain rarely studied. The aim of this study was to prospectively determine the incidence of major complications (neurological and infectious) in post-operative adult patients with a continuous popliteal catheter inserted by the anatomical posterior approach for analgesia after foot surgery.

All popliteal catheters were placed pre-operatively under sterile conditions with the aid of a nerve stimulator technique. The primary outcome measure was the incidence of major complications including infection and neuropathy. As a secondary outcome, adverse effects as well as other complications were also evaluated. Data were expressed as median [25th-75th percentiles].

A total of 400 patients were included in the study during a 2-year period. The median time the catheter remained indwelling was 47 h [23, 54]. Major complications included three events (0.75%) with one infection (0.25%) and two neuropathies (0.50%). Three blocks were unsuccessful and the catheter insertion was difficult in 12 patients (3%). During the CPSNB procedure, one patient reported slight paraesthesia during stimulation. Patient satisfaction was scored at 4 for 89%, 3 for 6% and 2 for 5% on the analogue scale.

Major complications after the use of CPSN are not in fact rare. The incidence of severe neuropathy or infection complications is, respectively, 0.50% and 0.25%. However, the insertion of CPSN could be considered effective and is associated with only a few minor complications.