Comparison of ultrasound guided saphenous nerve block with two different anatomical approach

Surgery for below-knee is a very common procedure that performed by orthopedics and traumatology departments. As a femoral nerve terminal extension, saphenous nerve passes through adductor channel, it descends vertically along the medial side of the knee, then passes along the tibial side of the leg and provides sensorial innervation of the lower extremity. Saphenous nerve block can be applied in addition to the sciatic nerve block, for knee operations that do not require a tourniquet.Krombach et al. used subsartoriyal approach and Şahin et al. used infracondylar medial approach for saphenous nerve block.The aim of this study was to compare the clinical applicability and outcome of saphenous nerve blocks with two different anatomical approach. Saphenous nerve block in addition with sciatic nerve block planned patients whom scheduled for below knee surgery between 18-65 years of age, 60 patients with ASA physical status I-III were randomized in groups and included in the study. Patients whom have anticoagulant therapy, coagulation disorder, local infection at the injection area, peripheral neuropathy or refuse the procedure and patients undergoing lower limb amputation were excluded. Patients were randomly divided into subsartorial and infracondylar medial saphenous nerve block groups. In subsartorial group, after linear ultrasound probe was placed transverse to 1/3 distal of leg, nervus saphenous displayed under m. sartorius and between m. vastus medialis, m. magnus, m. gracilis, m. adductor. In medial infracondylar group, ultrasound probe was placed transversely at the distal of medial condyle and nervus saphenous displayed between aponeurozis of m.gracilis and m.sartorius. In both approaches, in-plane technique 5ml of mixture that include levobupivokain 0.25% and 1% lidocaine was performed with using 80 mm insulated 22 gauge needle. Pin-prick test was used for examination of sensory block. After saphenous nerve block, ultrasound guided sciatic nerve block performed from subgluteal region using 20 ml of the same mixture of local anesthetics. Saphenous nerve block processing time (BIS), block onset time (BBZ) and the duration of sensorial block (DBS) time were recorded.Between compared groups duration of sensorial block time was statictically longer in subsartorial group than infracondylar medial group, respectively, 413,5 ± 64,23 min and 367,05 ± 51.03 min. (p<0.01). Compared with subsartorial saphenous nerve block performed by Krombach et al., ultrasound-guided medial saphenous nerve block with infracondylar approach described by Sahin et al. can be applied as an alternative method although provides shorter block time.Keywords: Saphenous nerve block, Ultrasound,