Use of a stimulating catheter for total knee replacement surgery: preliminary results

Background. There is continuing debate as to whether the useof electrical stimulation that aids in localizing nerves isalso beneficial for optimizing placement of nerve cathetersand lead to improved clinical outcomes, such as reductions inpain scores and opioid consumption. Methods. We undertook a retrospective, non-randomized comparisonof stimulating and non-stimulating nerve catheters in 419 patientsundergoing total knee replacement between December 2002 andJuly 2004. Before surgery, patients received sciatic and femoralnerve blocks with a catheter for the femoral nerve. In 159 patientsa stimulating catheter system (Stimucath; Arrow International,Reading, PA, USA) and in 260 patients a non-stimulating cathetersystem (Contiplex; B. Braun, Melsungen, Germany) was used. Aftersurgery, pain scores and morphine consumption were recordedat 4-h intervals until the first postoperative morning. In asubset of 85 patients, the postoperative evaluation period waslengthened to 3 days. Results. Postoperative visual analogue scores (VAS) for painwere similar in the two groups during the first 24 h (P=0.305).In patients followed for 3 days, VAS scores did not differ onany of the days (P=0.427). Total morphine consumption did notdiffer on the first postoperative day (mean [95% CI]: stimulating,12.4 [10.1–14.7] mg; non-stimulating 10.4 [8.9–11.8]mg; P=0.140) or on subsequent days. Conclusions. The practical advantages of the stimulating catheter,as reported by previous investigators, were not obvious in thisclinical situation. In terms of outcome measures such as painscores and morphine consumption, we found no significant differencesbetween stimulating and non-stimulating catheters.