Morphology of saphenous nerve in cadavers: a guide to saphenous block and surgical interventions / 대한해부학회지

The knowledge about detailed morphology and relation of saphenous nerve is important to obtain successful saphenous nerve regional blocks to achieve pre- and post-operative anesthesia and analgesia, nerve entrapment treatments and to avoid damage of saphenous nerve during knee and ankle surgeries. The literature describing detailed morphology of saphenous nerve is very limited. We dissected 42 formalin fixed well embalmed cadaveric lower limbs to explore detailed anatomy, relation and mode of termination of saphenous nerve and measured the distances from the nearby palpable bony landmarks. The average distance of origin of saphenous nerve from inguinal crease was 7.89±1.42 cm, the distance from upper end of medial border of patella to saphenous nerve at that level was 8.11±0.85 cm, distance from tibial tuberosity was 7.53±0.98 cm and from midpoint of anterior border of medial malleolus was 0.45±0.14 cm. Saphenous nerve provided two infrapatellar branches at the level of mid to lower limit of patellar ligament in 90% cases. It was in close contact or adhered to great saphenous vein across the lower 2/3rd of leg lying either anterior, posterior or deep to the vein. The saphenous nerve terminated by bifurcating proximal to medial malleolus in majority of cases though no obvious bifurcation was observed in 9.52% cases. The detailed morphology, relations and the distances from palpable bony landmarks may be helpful for clinicians to achieve successful saphenous nerve block and to avoid saphenous nerve damage and related complications during orthopedic procedures.

Regional Anesthesia of Lower Extremity using Tibial Nerve and Saphenous Nerve Block

Lower leg reconstruction has been performed with greater frequency under general or spinal anesthesia. But for patients with difficult problem in general or spinal anesthesia such as myocardial ischemia and end-stage renal failure, regional block techniques have been advocated. The regional block involved the tibial and saphenous nerve is performed as the following; two points of insertion of the needle are defined in lateral to popliteal pulsation and posterior to medial femoral condyle. We use 10cc of 0.25% bupivacaine for popliteal area block and 10cc of it for saphenous nerve block. In these techniques the major landmark for needle insertion is the popliteal artery. In all patients(19 cases) the techniques formed part of lower leg block for lower leg reconstruction. It was successful in 18 cases except in one case which failed initially but was successful at the following trial. There were no complications associated with these techniques. There were no incidents of postoperative neuralgia or neuropraxia. Lower leg anesthesia with saphenous nerve block and tibial nerve block offers numerous advantages that make it a suitable anesthetic technique. These facts suggest that the performances of these blocks are safe and effective anesthetic technique for lower leg reconstruction.