Rare neurological complications subsequent to brachial plexus block: a case report and literature review

Brachial plexus block anesthesia is widely utilized for upper limb surgical procedures in clinical settings. The diffusion of local anesthetics within the intermuscular sulcus structure can lead to nerve paralysis. However, we report an exceptionally rare case of concurrent extensive neural blockade, with a spread far beyond expected boundaries, which carries significant clinical cautionary implications. This case report described a previously healthy patient who successfully underwent arthroscopic rotator cuff repair on the right shoulder under general anesthesia combined with a brachial plexus block. Following an ultrasound-guided intermuscular groove approach for brachial plexus block and superficial cervical plexus block, the patient developed numbness and reduced muscle strength in the right upper and lower limbs, along with unresponsiveness to painful stimuli. This paralysis lasted for at least 48 hours. Postoperative cranial computerized tomography (CT) and cervical X-ray showed no significant abnormalities. No neurological sequelae were observed after the complete resolution of the anesthetic effect. Necessary but limited tests and examinations were performed to establish a differential diagnosis, effectively excluding cerebral infarction, spinal disorders, peripheral vascular and nerve diseases, electrolyte abnormalities, and hysteria. While it is hypothesized that local anesthetics may contribute to lower limb paralysis, the specific mechanism by which these agents affect the nerves in this region remains unclear and requires further investigation.