Résumé
We tested the effectiveness of bilateral continuous paravascular femoral nerve blocks in a patient following bilateral femoral shaft surgery in whom other analgesic regimens were considered contraindicated or of limited effectiveness.
Bilateral continuous femoral paravascular nerve blocks were performed using a previously described technique. General anesthesia was subsequently used to facilitate surgery, which was a bilateral osteosynthesis using dynamic hip screws for osteolytic metastases of the proximal extremities of both femurs. A continuous infusion of lidocaine, morphine, and clonidine was established in both femoral catheters preoperatively and used postoperatively as the principle source of analgesia. Radiographic contrast was used to document the position of both catheters and to document the spread of injectate. Visual analog scale (VAS) pain scores were recorded in the recovery room and at 4, 16, 24, 48, and 72 hours postoperatively. Plasma lidocaine levels were determined by gas chromatography at 4, 16, and 48 hours postoperatively. Sensory assessment in the distribution of the femoral, lateral cutaneous, and obturator nerves was performed to confirm the presence of sensory blockade.
We successfully provided analgesia with bilateral continuous femoral paravascular nerve blocks. Pain scores at rest were consistently rated good to excellent (VAS < 20 mm). Evidence of sensory conduction block was present throughout the infusion. Plasma concentrations of lidocaine were consistently below toxic levels (1.35 to 1.65 μg/ml). Radiographic contrast studies failed to demonstrate movement of contrast to the level of the lumbar plexus.
Bilateral continuous femoral paravascular nerve blocks can be used to provide effective and safe analgesia in patients requiring aggressive analgesia in whom other techniques may be contraindicated.