Prolonged Neural Block After Lower-Limb Nerve Blocks in a Patient with Inherited Antithrombin III Deficiency: Implications for Regional Anesthesia.

Purpose: Peripheral nerve block safety and pharmacology for patients with inherited antithrombin III (ATIII) deficiency remains unclear because of the rarity of the disease. Here, we report a case of unexpectedly prolonged motor and sensory inhibition following single-shot femoral and sciatic nerve blocks in a patient with inherited ATIII deficiency. We hypothesized that venous stasis, microcirculatory impairment, elevated peripheral venous pressure, and increased local tissue pressure might have contributed to prolonged nerve dysfunction and peripheral nerve injury. Case Report: The patient was a 58-year-old man (170 cm, 69 kg) with inherited ATIII deficiency. He was scheduled for 1-hour surgical debridement of recurrent venous stasis ulcers with microcirculatory impairment on his lower left leg. Nerve blocks resulted in motor and sensory deficits in the lower leg that lasted 2 and 8 days, respectively. The prolonged duration of this nerve block might have been related to his inherited ATIII deficiency. This condition can contribute to thrombosis of vessels such as the inferior vena cava, potentially leading to venous microcirculatory impairment in the lower limbs and complex coagulopathy. Conclusion: While peripheral nerve blocks are widely used for their efficacy and safety, the risk-benefit profile of regional anesthesia may be atypical in patients with coagulation disorders. This case highlights the need for cautious nerve block administration in patients with inherited ATIII deficiency.