gms | German Medical Science

Objective: The drop foot substantially hinders the mobility of patients with chronic ischemic or hemorrhagic stroke. An orthesis or external stimulator are the common therapeutic options which have the shortcomings of being cumbersome during activities of daily living and being painful (external stimulation). Recently a hybrid system with external sensor and antenna and internal stimulator for activation of the peroneal nerve (resulting in dorsiflexion) has been introduced, but up to date no larger series exist. The aim of the study is to report the safety aspects of this new implant device after having performed 45 implantations.

Method: Since 2008, the peroneal stimulator has been implanted in 45 patients with chronic stroke. In the last 43 implantations, an institutional standardized operative procedure was used. All patients underwent pre- and postoperative testing of gait velocity and walking distance. The postoperative investigations were performed on day 42 and 84. Surgery-associated complications were prospectively registered.

Results: In the first 2 patients, 1 nerve damage due to cuff movement into the branching area of the sensory branch and one case of painful sensations were seen, initiating a standardization of the surgical procedure and the postoperative care. In the following 43 patients, sustained good implant function with significantly improved gait velocity was seen. In 2 patients, infection made implant removal after initial good function necessary. Another two patients suffered from postoperative re-bleeding that had to be revised in a second operation. In total, the complication rate was 13.3%, after initiation of the standardized surgical procedure the rate dropped to 8.9%. After optimizing infection prophylaxis, no further postoperative wound infection occurred and complication rate was reduced to 5% in the last 20 patients (one case of re-bleeding).

Conclusions: The peroneal stimulator is a promising therapeutic option for the management of drop foot in chronic stroke patients. A standardized surgical protocol is useful to achieve optimal clinical results with a reduction of surgery-associated complications. Surgery should be limited to specialized clinics, as the results of our safety trial demonstrate the learning curve associated with this implant device.