Long-term analgesic efficacy of an ultrasound guided single-shot adductor canal block in patients undergoing total knee arthroplasty

Background and Goal of Study: It is difficult to evaluate the deepness and wideness of sympathetic block, provided by regional anaesthesia, compared to motor and sensory components. Changes in skin temperature may be useful in this content.Materials and methods: The skin temperature in different regions of lower extremity was measured with infrared thermometer before and after epidural block in 16 patients. The epidural anesthesia was performed in L3-L4 with 18 ml 0.5% bupivacaine. The skin regions were taken in accordance with innervation: nervus ischiadicus - heel and big toe, nervus femoralis - anterior surface of knee, nervus obturatorius - medial surface of thigh, nervus cutaneus femoris lateralis - lateral surface of thigh. All results are given as Mean u00b1 standard deviation. Results and discussion: The skin temperature on the plantar surface of heel increased from 24.2u00b13.1u1d3cC to 28.4u00b14.6u1d3cC (P=0.0071). On the big toe temperature increased from 21.2u00b12.3u1d3cC to 27.5u00b15.8u1d3cC (P=0.0076). On the anterior surface of knee the temperature was not changed (32.8u00b11.21u1d3cC before and 32.8u00b11.42u1d3cC after epidural anaesthesia; P=0.39). On the medial surface of thigh the temperature increased insignificantly (31.7u00b10.8u1d3cC before and 32.2u00b11.43u1d3cC after epidural anaesthesia; P=0.29). On the lateral surface of thigh the temperature slightly decreased (30.3u00b12.3u1d3cC before and 30.0u00b12.7u1d3cC after epidural anaesthesia; P=0.28).Conclusion(s): Under epidural anaesthesia the skin temperature of legs significantly increases in distal regions.